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Sample records for based sanex solvent

  1. Minor actinide separation: simplification of the DIAMEX-SANEX strategy by means of novel SANEX processes

    Energy Technology Data Exchange (ETDEWEB)

    Geist, A. [Karlsruher Institut fuer Technologie - KIT, INE, P. O. Box 3640, 76021 Karlsruhe (Germany); Modolo, G.; Wilden, A.; Kaufholz, P. [Forschungszentrum Juelich GmbH, IEK-6, Juelich (Germany)

    2013-07-01

    The separation of An(III) from PUREX raffinate has previously been demonstrated by applying a DIAMEX process (i.e., co-extraction of An(III) and Ln(III) from HAR) followed by a SANEX process (i.e., selective extraction of An(III) from the DIAMEX product containing An(III) + Ln(III)). In line with process intensification issues, more compact processes have been developed: Recently, a 1c-SANEX process test was successfully performed, directly extracting An(III) from PUREX HAR. More recently, a new i-SANEX process was successfully tested. This process is based on the co-extraction of An(III) + Ln(III) into a TODGA solvent, followed by a selective back-extraction of An(III) by a water soluble complexing agent, in this case SO{sub 3}-Ph-BTP. In both cases, good recoveries were achieved, and very pure product solutions were obtained. However, both 1c-SANEX and i-SANEX used non-CHON chemicals. Nevertheless, these processes are a simplification to the DIAMEX + SANEX process as only one solvent is used. Finally, the new i-SANEX process is the most compact process. (authors)

  2. Innovative SANEX process for trivalent actinides separation from PUREX raffinate

    Energy Technology Data Exchange (ETDEWEB)

    Sypula, Michal

    2013-07-01

    Recycling of nuclear spent fuel and reduction of its radiotoxicity by separation of long-lived radionuclides would definitely help to close the nuclear fuel cycle ensuring sustainability of the nuclear energy. Partitioning of the main radiotoxicity contributors followed by their conversion into short-lived radioisotopes is known as partitioning and transmutation strategy. To ensure efficient transmutation of the separated elements (minor actinides) the content of lanthanides in the irradiation targets has to be minimised. This objective can be attained by solvent extraction using highly selective ligands that are able to separate these two groups of elements from each other. The objective of this study was to develop a novel process allowing co-separation of minor actinides and lanthanides from a high active acidic feed solution with subsequent actinide recovery using just one cycle, so-called innovative SANEX process. The conditions of each step of the process were optimised to ensure high actinide separation efficiency. Additionally, screening tests of several novel lipophilic and hydrophilic ligands provided by University of Twente were performed. These tests were aiming in better understanding the influence of the extractant structural modifications onto An(III)/Ln(III) selectivity and complexation properties. Optimal conditions for minor actinides separation were found and a flow-sheet of a new innovative SANEX process was proposed. Tests using a single centrifugal contactor confirmed high Eu(III)/Am(III) separation factor of 15 while the lowest SF{sub Ln/Am} obtained was 6,5 (for neodymium). In addition, a new masking agent for zirconium was found as a substitution for oxalic acid. This new masking agent (CDTA) was also able to mask palladium without any negative influence on An(III)/Ln(III). Additional tests showed no influence of CDTA on plutonium present in the feed solution unlike oxalic acid which causes Pu precipitation. Therefore, CDTA was proposed as

  3. Solvent

    OpenAIRE

    Hamida Y. Mostafa; Ebaa A. El-Shamy; Amal S. Farag; Nadia G. Kandile

    2013-01-01

    Neat ethylacetoacetate (EAA) and its mixtures with a co-solvent and an anti-solvent have been studied for refining of heavy wax distillate fraction to produce substantially non-carcinogenic base oil. The co-solvent and anti-solvent used are dipropylene glycol (DPG) and ethylene glycol (EG) respectively. The solubility characteristics of the main solvent and its mixed solvent systems were studied. Selection of the optimum solvent mixture and extraction variables has been studied. The effect of...

  4. Partnew - New solvent extraction processes for minor actinides - final report; Partnew - Nouveaux procedes d'extraction par solvant pour les actinides mineurs - rapport final

    Energy Technology Data Exchange (ETDEWEB)

    Madic, C.; Testard, F.; Hudson, M.J.; Liljenzin, J.O.; Christiansen, B.; Ferrando, M.; Facchini, A.; Geist, A.; Modolo, G.; Gonzalez-Espartero, A.; Mendoza, J. de

    2004-07-01

    The objectives of the European project PARTNEW were to define solvent extraction processes for the partitioning of the minor actinides, Am and Cm, from the aqueous high active raffinate or high active concentrate issuing the reprocessing of nuclear spent fuels by the PUREX process. Eleven laboratories participated to the research: 1/ CEA-DEN (Marcoule), 2/ CEA-DSM (Saclay), 3/ UREAD (U.K.), 4/ CTU (Sweden), 5/ ITU (Germany), 6/ ENEA (Italy), 7/ PoliMi (Italy), 8/ FZK-INE (Germany), 9/ FZJ-ISR (Germany), 10/ CIEMAT (Spain) and 11/ UAM (Spain). The research was organised into eight work packages (WP): Basic and applied DIAMEX studies, using diamide extractants for the co-extraction of actinides(III) (An(III)) and lanthanides(III) (Ln(III)) nitrates (WP1 and WP2), Basic and applied SANEX studies based on the use of polydentate N-ligands for the An(III)/Ln(III) separation (WP3 and WP4), Basic and applied SANEX studies based on the use of synergistic mixtures made of bis-(chloro-phenyl)-di-thio-phosphinic acid + neutral O-bearing ligand, (WP5 and WP6), Basic SANEX studies for the An(III)/Ln(III) separation, based on the use of new S-bearing ligands, Basic and applied studies for the Am(III)/Cm(III) separation. The work done in the fundamental and applied domains was very fruitful. Several processes have been successfully tested with genuine high active raffinates and concentrate. (authors)

  5. Physico chemical properties of irradiated i-SANEX diluents

    Directory of Open Access Journals (Sweden)

    Mossini Eros

    2015-12-01

    Full Text Available The development of effective processes to recover minor actinides from spent nuclear fuel cannot leave out of consideration the evaluation of the impact of ionizing radiations on safety, fluid dynamics and extraction efficiency. It is common knowledge from the literature that radiation damage mainly affects the diluents and, indirectly, the extractants [1], but a lack of knowledge remains regarding the radiolytic behavior of innovative selective actinide extraction (i-SANEX diluents [2, 3]. As natural prosecution of the work already performed on diluted nitric acid solutions [4], 0.44 M nitric acid solutions were irradiated in contact with a mixture of kerosene + 5 vol.% 1-octanol by a Co-60 source at 2.5 kGy/h dose rate and up to 100 kGy absorbed dose, conditions of interest for the future industrial facility. Density, viscosity, acidity, nitrate anion concentration and phase transfers were systematically measured before and after γ-irradiation. This was performed because radiation-induced modifications of these parameters may induce alterations of both the fluid dynamics and the separation performances of the extracting system. The results suggest that the fluid-dynamics of the system should be unaltered. In fact, only slight alterations of the organic phase viscosity and of the aqueous phase acidity were measured after irradiation, suggesting the occurrence of limited phase transfers and of diluent by-products formation.

  6. Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, D. [European Commission, Joint Research Center, Karlsruhe (Germany). Inst. for Transuranium Elements; Chalmers Univ. of Technology, Gothenburg (Sweden). Nuclear Chemistry, Dept. of Chemical and Biological Engineering; Christiansen, B.; Glatz, J.P.; Malmbeck, R.; Serrano-Purroy, D. [European Commission, Joint Research Center, Karlsruhe (Germany). Inst. for Transuranium Elements; Modolo, G. [Forschungszentrum Juelich GmbH (Germany). Inst. for Energy Research, Safety Research and Reactor Technology; Sorel, C. [Commissariat a l' Energie Atomique Valrho (CEA), DRCP/SCPS, Bagnols-sur-Ceze (France)

    2009-07-01

    The design of an efficient process flow-sheet requires accurate extraction data for the experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and to compare this with equilibrium batch experiments for a SANEX system based on CyMe{sub 4}-BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. The results show that even with low flow rates, only around 9% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). In the hot test the lanthanide scrubbing was inefficient whereas in the stripping both the actinides and the lanthanides showed good results. Based on these results improvements of the suggested flow-sheet is discussed. (orig.)

  7. The separation of extractants implemented in the DIAMEX-SANEX process

    Energy Technology Data Exchange (ETDEWEB)

    Heres, Xavier [CEA-Marcoule, DEN/MAR/DRCP/SCPS, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Baron, P.; Hill, C.; Ameil, E.; Martinez, I. [CEA-Marcoule, DEN/MAR/DRCP/SCPS, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Rivalier, P. [CEA-Marcoule, DEN/MAR/DTEC/SGCS, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France)

    2008-07-01

    DIAMEX-SANEX is a process developed at the Cea to recover selectively the actinides(III) after a COEX{sup TM} or a PUREX process, in order to significantly decrease the radiotoxicity of the ultimate waste produced by the nuclear industry. This liquid-liquid extraction process is based on the DIAMEX process, using a malonamide supplemented by an acidic extractant. Besides an actinide extraction step and a lanthanide stripping step are implemented an actinide(III) stripping step and an extractant splitting step. The latter is carried out to avoid interactions between these two extractants during the first co-extraction step of the actinides and the lanthanides. This paper gives some results obtained with di-n-hexyl phosphoric acid (HDHP), which fulfills the required criteria for process development. Batch experiments or cold counter-current tests showed that it is possible to separate this extractant from DMDOHEMA. HDHP can moreover maintain the lanthanides(III) in the organic phase when the actinides(III) are back extracted from the organic phase. (authors)

  8. Acids and bases solvent effects on acid-base strenght

    CERN Document Server

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  9. Glycerol based solvents: synthesis, properties and applications

    OpenAIRE

    García, José I.; García-Marín, Héctor; Pires, Elísabet

    2014-01-01

    The most recent advances in the use of glycerol and glycerol derivatives as solvents are reviewed. There are an increasing number of examples of the use of glycerol itself as a reaction medium, solvent-reagent or a dispersive medium for a large variety of applications. In the case of glycerol derivatives, new synthetic methods, physico-chemical properties and application examples as solvents are revised. Recent studies in the field of solvent classification, as well as solvent substitution is...

  10. Molecular and supramolecular speciations of solvent extraction systems based on malonamide and/or dialkyl-phosphoric acids for An(III)/Ln(III); Speciations moleculaire et supramoleculaire de systemes d'extraction liquide-liquide a base de malonamide et/ou d'acides dialkylphosphoriques pour la separation An(III)/Ln(III)

    Energy Technology Data Exchange (ETDEWEB)

    Gannaz, B

    2006-06-15

    The solvent extraction system used in the DIAMEX-SANEX process, developed for the actinide(III)/lanthanide(III) separation, is based on the use of mixtures of the malonamide DMDOHEMA and a dialkyl-phosphoric acid (HDEHP or HDHP), in hydrogenated tetra-propylene. The complexity of these systems urges on a novel approach to improve the conventional methods (thermodynamics, solvent extraction) which hardly explain the macroscopic behaviors observed (3. phase, over-stoichiometry). This approach combines studies on both supramolecular (VPO, SANS, SAXS) and molecular (liquid-liquid extraction, ESI-MS, IR, EXAFS) speciations of single extractant systems (DMDOHEMA or HDHP in in n-dodecane) and their mixture. In spite of safety constraints due to the handling of radio-material, they were used in the studies as much as possible, like for SAXS measurements on americium-containing samples, a worldwide first-time. In each of the investigated systems, actinides(III) and lanthanides(III) are extracted to the organic phase in polar cores of reversed micelles, the inner and outer-sphere compositions of which are proposed. Thus, the 4f and 5f cations are extracted by reversed micelles such as [(DMDOHEMA){sub 2}M(NO{sub 3}){sub 3}]{sub inn} (DMDOHEMA){sub x}(HNO{sub 3}){sub z}(H{sub 2}O){sub w}]{sub out} and M(DHP){sub 3}(HDHP){sub y-3}(H{sub 2}O){sub w} with y = 3 to 6, for the single extractant systems. In the case of the two extractants system, the less concentrated one acts like a co-surfactant regarding the mixed aggregate formation [(DMDOHEMA){sub 2}M(NO{sub 3}){sub 3-v}(DHP){sub v}]{sub inn} [(DMDOFIEMA){sub x}(HDHP){sub y}(HNO{sub 3})z(H{sub 2}O){sub w}]{sub out}. (author)

  11. Optimal (Solvent) Mixture Design through a Decomposition Based CAMD methodology

    DEFF Research Database (Denmark)

    Achenie, L.; Karunanithi, Arunprakash T.; Gani, Rafiqul

    2004-01-01

    Computer Aided Molecular/Mixture design (CAMD) is one of the most promising techniques for solvent design and selection. A decomposition based CAMD methodology has been formulated where the mixture design problem is solved as a series of molecular and mixture design sub-problems. This approach is...... is able to overcome most of the difficulties associated with the solution of mixture design problems. The new methodology has been illustrated with the help of a case study involving the design of solvent-anti solvent binary mixtures for crystallization of Ibuprofen.......Computer Aided Molecular/Mixture design (CAMD) is one of the most promising techniques for solvent design and selection. A decomposition based CAMD methodology has been formulated where the mixture design problem is solved as a series of molecular and mixture design sub-problems. This approach...

  12. A knowledge based advisory system for acid/base titrations in non-aqueous solvents

    NARCIS (Netherlands)

    Bos, M.; Linden, van der W.E.

    1996-01-01

    A computer program was developed that could advice on the choice of solvent and titrant for acid/base titrations in nonaqueous media. It is shown that the feasibility of a titration in a given solvent can be calculated from solvent properties and intrinsic acid/base properties of the sample componen

  13. Rare earth element enrichment using membrane based solvent extraction

    Science.gov (United States)

    Makertiharta, I. G. B. N.; Dharmawijaya, P. T.; Zunita, M.; Wenten, I. G.

    2017-01-01

    The chemical, catalytic, electrical, magnetic, and optical properties of rare earth elements are required in broad applications. Rare earth elements have similar physical and chemical properties thus it is difficult to separate one from each other. Rare earth element is relatively abundant in earth's crust but rarely occur in high concentrated deposits. Traditionally, ion-exchange and solvent extraction techniques have been developed to separate and purify single rare earth solutions or compounds. Recently, membrane starts to gain attention for rare earth separation by combining membrane and proven technologies such as solvent extraction. Membrane-based process offers selective, reliable, energy efficient and easy to scale up separation. During membrane-based separation process, one phase passes through membrane pores while the other phase is rejected. There is no direct mixing of two phases thus the solvent loss is very low. Membrane can also lower solvent physical properties requirement (viscosity, density) and backmixing, eliminate flooding phenomenon and provide large interfacial area for mass transfer. This paper will summarize research efforts in developing membrane technology for rare earth element separation. Special attention will be given to solvent extraction related process as the commonly used method for rare earth element separation. Furthermore, membrane configuration and its potentials will also be discussed.

  14. Solvent extraction of gold using ionic liquid based process

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Zunita, Megawati; Rizki, Z.; Dharmawijaya, P. T.

    2017-01-01

    In decades, many research and mineral processing industries are using solvent extraction technology for metal ions separation. Solvent extraction technique has been used for the purification of precious metals such as Au and Pd, and base metals such as Cu, Zn and Cd. This process uses organic compounds as solvent. Organic solvents have some undesired properties i.e. toxic, volatile, excessive used, flammable, difficult to recycle, low reusability, low Au recovery, together with the problems related to the disposal of spent extractants and diluents, even the costs associated with these processes are relatively expensive. Therefore, a lot of research have boosted into the development of safe and environmentally friendly process for Au separation. Ionic liquids (ILs) are the potential alternative for gold extraction because they possess several desirable properties, such as a the ability to expanse temperature process up to 300°C, good solvent properties for a wide range of metal ions, high selectivity, low vapor pressures, stability up to 200°C, easy preparation, environmentally friendly (commonly called as "green solvent"), and relatively low cost. This review paper is focused in investigate of some ILs that have the potentials as solvent in extraction of Au from mineral/metal alloy at various conditions (pH, temperature, and pressure). Performances of ILs extraction of Au are studied in depth, i.e. structural relationship of ILs with capability to separate Au from metal ions aggregate. Optimal extraction conditon in order to gain high percent of Au in mineral processing is also investigated.

  15. Carbon dioxide-based supercritical fluids as IC manufacturing solvents

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, J.B.; Davenhall, L.B.; Taylor, C.M.V.; Sivils, L.D.; Pierce, T.; Tiefert, K.

    1999-05-11

    The production of integrated circuits (IC's) involves a number of discrete steps which utilize hazardous or regulated solvents and generate large waste streams. ES&H considerations associated with these chemicals have prompted a search for alternative, more environmentally benign solvent systems. An emerging technology for conventional solvent replacement is the use of supercritical fluids based on carbon dioxide (CO{sub 2}). Research work, conducted at Los Alamos in conjunction with the Hewlett-Packard Company, has lead to the development of a CO{sub 2}-based supercritical fluid treatment system for the stripping of hard-baked photoresists. This treatment system, known as Supercritical CO{sub 2} Resist Remover, or CORR, uses a two-component solvent composed of a nonhazardous, non-regulated compound, dissolved in supercritical CO{sub 2}. The solvent/treatment system has been successfully tested on metallized Si wafers coated with negative and positive photoresist, the latter both before and after ion-implantation. A description of the experimental data will be presented. Based on the initial laboratory results, the project has progressed to the design and construction of prototype, single-wafer photoresist-stripping equipment. The integrated system involves a closed-loop, recirculating cycle which continuously cleans and regenerates the CO{sub 2}, recycles the dissolved solvent, and separates and concentrates the spent resist. The status of the current design and implementation strategy of a treatment system to existing IC fabrication facilities will be discussed. Additional remarks will be made on the use of a SCORR-type system for the cleaning of wafers prior to processing.

  16. Effects of temperature and solvent concentration on the solvent crystallization of palm-based dihydroxystearic acid with isopropyl alcohol

    Institute of Scientific and Technical Information of China (English)

    Gregory F.L.Koay; Teong-Guan Chuah; Sumaiya Zainal-Abidin; Salmiah Ahmad; Thomas S.Y.Choong

    2012-01-01

    Palm-based dihydroxystearic acid of 69.55% purity was produced in a 500-kg-per-batch operation pilot plant and purified through solvent crystallization in a custom fabricated simultaneous batch crystallizer unit.The effects of temperature and solvent concentration on yield,particle size distribution and purity were studied.The purity was higher,while the yield and particle size were lower and smaller,respectively,at higher temperature and solvent concentration.The solvent crystallization process efficiency was rated at 66-69% when carried out with 70-80% isopropyl alcohol at 20 ℃.

  17. Improving agar electrospinnability with choline-based deep eutectic solvents.

    Science.gov (United States)

    Sousa, Ana M M; Souza, Hiléia K S; Uknalis, Joseph; Liu, Shih-Chuan; Gonçalves, Maria P; Liu, LinShu

    2015-09-01

    Very recently our group has produced novel agar-based fibers by an electrospinning technique using water as solvent and polyvinyl alcohol (PVA) as co-blending polymer. Here, we tested the deep eutectic solvent (DES), (2-hydroxyethyl)trimethylammonium chloride/urea prepared at 1:2 molar ratio, as an alternative solvent medium for agar electrospinning. The electrospun materials were collected with an ethanol bath adapted to a previous electrospinning set-up. One weight percent agar-in-DES showed improved viscoelasticity and hence, spinnability, when compared to 1 wt% agar-in-water and pure agar nanofibers were successfully electrospun if working above the temperature of sol-gel transition (∼80 °C). By changing the solvent medium we decreased the PVA concentration (5 wt% starting solution) and successfully produced composite fibers with high agar contents (50/50 agar/PVA). Best composite fibers were formed with the 50/50 and 30/70 agar/PVA solutions. These fibers were mechanically resistant, showed tailorable surface roughness and diverse size distributions, with most of the diameters falling in the sub-micron range. Both nano and micro forms of agar fibers (used separately or combined) may have potential for the design of new and highly functional agar-based materials.

  18. How polar are choline chloride-based deep eutectic solvents?

    Science.gov (United States)

    Pandey, Ashish; Rai, Rewa; Pal, Mahi; Pandey, Siddharth

    2014-01-28

    Developing and characterizing green solvents with low toxicity and cost is one of the most important issues in chemistry. Deep Eutectic Solvents (DESs), in this regard, have shown tremendous promise. Compared to popular organic solvents, DESs possess negligible VOCs and are non-flammable. Compared to ionic liquids, which share many characteristics but are ionic compounds and not ionic mixtures, DESs are cheaper to make, much less toxic and mostly biodegradable. An estimate of the polarity associated with DESs is essential if they are to be used as green alternatives to common organic solvents in industries and academia. As no one physical parameter can satisfactorily represent solute-solvent interactions within a medium, polarity of DESs is assessed through solvatochromic optical spectroscopic responses of several UV-vis absorbance and molecular fluorescence probes. Information on the local microenvironment (i.e., the cybotactic region) that surrounds several solvatochromic probes [betaine dye, pyrene, pyrene-1-carboxaldehyde, 1-anilino-8-naphthalene sulfonate (ANS), p-toluidinyl-6-naphthalene sulfonate (TNS), 6-propionyl-2-(dimethylaminonaphthalene) (PRODAN), coumarin-153, and Nile Red] for four common and popular DESs formed from choline chloride combined with 1,2-ethanediol, glycerol, urea, and malonic acid, respectively, in 1 : 2 molar ratios termed ethaline, glyceline, reline, and maline is obtained and used to assess the effective polarity afforded by each of these DESs. The four DESs as indicated by these probe responses are found to be fairly dipolar in nature. Absorbance probe betaine dye and fluorescence probes ANS, TNS, PRODAN, coumarin-153, and Nile Red, whose solvatochromic responses are based on photoinduced charge-transfer, imply ethaline and glyceline, DESs formed using alcohol-based H-bond donors, to be relatively more dipolar in nature as compared to reline and maline. The pyrene polarity scale, which is based on polarity-induced changes in

  19. A knowledge based advisory system for acid/base titrations in non-aqueous solvents

    OpenAIRE

    1996-01-01

    A computer program was developed that could advice on the choice of solvent and titrant for acid/base titrations in nonaqueous media. It is shown that the feasibility of a titration in a given solvent can be calculated from solvent properties and intrinsic acid/base properties of the sample components. A consistent set of properties for various solvents and a large number of acidic and basic compounds was calculated from literature data with the use of a genetic algorithm. Test results show t...

  20. Opportunities for Bio-Based Solvents Created as Petrochemical and Fuel Products Transition towards Renewable Resources

    Directory of Open Access Journals (Sweden)

    James H. Clark

    2015-07-01

    Full Text Available The global bio-based chemical market is growing in size and importance. Bio-based solvents such as glycerol and 2-methyltetrahydrofuran are often discussed as important introductions to the conventional repertoire of solvents. However adoption of new innovations by industry is typically slow. Therefore it might be anticipated that neoteric solvent systems (e.g., ionic liquids will remain niche, while renewable routes to historically established solvents will continue to grow in importance. This review discusses bio-based solvents from the perspective of their production, identifying suitable feedstocks, platform molecules, and relevant product streams for the sustainable manufacturing of conventional solvents.

  1. Colorimetric solvent indicators based on Nafion membranes incorporating nickel(II)-chelate complexes.

    Science.gov (United States)

    Hosokawa, Hitoshi; Funasako, Yusuke; Mochida, Tomoyuki

    2014-11-10

    To develop solvent-recognition films, Nafion membranes incorporating cationic nickel-chelate complexes, that is, [Ni(L(1))(L(2))](+) (HL(1) = acetylacetone, 2,2,6,6-tetramethyl-3,5-heptanedione; L(2) = N,N-diethylethylenediamine, N-butyl-N,N',N'-trimethylethylenediamine), were prepared. Immersion of the films in various solvents effected the color changes varying from red to pale blue green depending on the donor number of the solvents. The color change is based on an equilibrium shift between square-planar and solvent-coordinated octahedral geometries of the cations. The degree of the color change depended on the affinity of the incorporated complex to the solvent molecules. The films were robust and exhibited a reversible solvent response. The films exhibited thermochromism when a small amount of appropriate solvents were incorporated and changed from pale blue green at low temperatures to red at high temperatures.

  2. Photonic Crystal Based Sensor for Organic Solvents and for Solvent-Water Mixtures

    Directory of Open Access Journals (Sweden)

    Otto S. Wolfbeis

    2012-12-01

    Full Text Available Monodisperse polystyrene nanoparticles with a diameter of 173 nm were incorporated into a polydimethylsiloxane matrix where they display an iridescent color that can be attributed to the photonic crystal effect. The film is of violet color if placed in plain water, but turns to red in the presence of the non-polar solvent n-hexane. Several solvents were studied in some detail. We show that such films are capable of monitoring the water content of ethanol/water mixtures, where only 1% (v/v of water leads to a shift of the peak wavelength of reflected light by 5 nm. The method also can be applied to determine, both visually and instrumentally, the fraction of methanol in ethanol/methanol mixtures. Here, a fraction of 1% of methanol (v/v results in a wavelength shift of 2 nm. The reflected wavelength is not influenced by temperature changes nor impeded by photobleaching. The signal changes are fully reversible and response times are <1 s.

  3. Biodiesel production from ethanolysis of DPO using deep eutectic solvent (DES) based choline chloride - ethylene glycol as co-solvent

    Science.gov (United States)

    Taslim, Indra, Leonardo; Manurung, Renita; Winarta, Agus; Ramadhani, Debbie Aditia

    2017-03-01

    Biodiesel is usually produced from transesterification using methanol or ethanol as alcohol. However, biodiesel produced using methanol has several disadvantages because methanol is toxic and not entirely bio-based as it is generally produced from petroleum, natural gas and coal. On the other hand, ethanol also has several disadvantages such as lower reactivity in transesterification process and formation of stable emulsion between ester and glycerol. To improve ethanolysis process, deep eutectic solvent (DES) was prepared from choline chloride and ethylene glycol to be used as co-solvent in ethanolysis. Deep eutectic solvent was prepared by mixing choline chloride and ethylene glycol at molar ratio of 1:2, temperature of 80 °C, and stirring speed of 300 rpm for 1 hour. The DES was characterized by its density and viscosity. The ethanolysis of DPO / Degummed Palm Oil was performed at 70 °C, ethanol to oil molar ratio of 9:1, catalyst (potassium hydroxide) concentration of 0.75 wt.% concentration, co-solvent (DES) concentration of 1, 2, 3, 4, 5 and 6 wt.%, stirring speed of 600 rpm, and reaction time of 1 hour. The obtained biodiesel was then characterized by its density, viscosity and ester content. The oil - ethanol phase condition was observed in reaction tube. The oil - ethanol phase with DES tends to form meniscus compared to that without DES. Which implied that oil and ethanol become more slightly miscible, which favours the reaction. Using DES as co-solvent in ethanolysis resulted in an increase in yield and easier purification. The esters properties met the international standards ASTM D6751, with highest yield achieved at 81.72 % with 99.35 % ethyl ester contents at 4% DES concentration.

  4. Green solvent-based approaches for synthesis of nanomaterials

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The use of green solvents (including supercritical fluids and ionic liquids) in the synthesis of nanomaterials is highlighted. The methods described can not only reduce or eliminate the use or generation of substances hazardous to health and the environment, but can also be used to efficiently prepare nanomaterials with high performances. The unique characteristics of green solvents are responsible for the green features and unusual advantages of these approaches.

  5. Cellulose solvent- and organic solvent-based lignocellulose fractionation enabled efficient sugar release from a variety of lignocellulosic feedstocks.

    Science.gov (United States)

    Sathitsuksanoh, Noppadon; Zhu, Zhiguang; Zhang, Y-H Percival

    2012-08-01

    Developing feedstock-independent biomass pretreatment would be vital to second generation biorefineries that would fully utilize diverse non-food lignocellulosic biomass resources, decrease transportation costs of low energy density feedstock, and conserve natural biodiversity. Cellulose solvent- and organic solvent-based lignocellulose fractionation (COSLIF) was applied to a variety of feedstocks, including Miscanthus, poplar, their mixture, bagasse, wheat straw, and rice straw. Although non-pretreated biomass samples exhibited a large variation in enzymatic digestibility, the COSLIF-pretreated biomass samples exhibited similar high enzymatic glucan digestibilities and fast hydrolysis rates. Glucan digestibilities of most pretreated feedstocks were ∼93% at five filter paper units per gram of glucan. The overall glucose and xylose yields for the Miscanthus:poplar mixture at a weight ratio of 1:2 were 93% and 85%, respectively. These results suggested that COSLIF could be regarded as a feedstock-independent pretreatment suitable for processing diverse feedstocks by adjusting pretreatment residence time only.

  6. EPR character of gadolinium complexes with noncyclic polyether Schiff bases and its solvent effects

    Institute of Scientific and Technical Information of China (English)

    姚克敏; 陈德余; 王晓南; 邓宁

    1996-01-01

    EPR characters of three new gadolinium complexes with noncydic polyether Schiff bases in powder or organic solvents, including various oxyethylene chain lengths and different substituting groups in ligands, are investigated respectively. Some regularities are summed up. The difference of EPR character in various solvents, particularly at different temperatures, has been examined. The ’single peak effect’ due to THF solvent at low temperature is observed for the first time. This phenomenon is explicated.

  7. Solvent cleanup using base-treated silica gel solid adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Tallent, O.K.; Mailen, J.C.; Pannell, K.D.

    1984-06-01

    A solvent cleanup method using silica gel columns treated with either sodium hydroxide (NaOH) or lithium hydroxide (LiOH) has been investigated. Its effectiveness compares favorably with that of traditional wash methods. After treatment with NaOH solution, the gels adsorb HNO/sub 3/, dibutyl phosphate (DBP), UO/sub 2//sup 2 +/, Pu/sup 4 +/, various metal-ion fission products, and other species from the solvent. Adsorption mechanisms include neutralization, hydrolysis, polymerization, and precipitation, depending on the species adsorbed. Sodium dibutyl phosphate, which partially distributes to the solvent from the gels, can be stripped with water; the stripping coefficient ranges from 280 to 540. Adsorption rates are diffusion controlled such that temperature effects are relatively small. Recycle of the gels is achieved either by an aqueous elution and recycle sequence or by a thermal treatment method, which may be preferable. Potential advantages of this solvent cleanup method are that (1) some operational problems are avoided and (2) the amount of NaNO/sub 3/ waste generated per metric ton of nuclear fuel reprocessed would be reduced significantly. 19 references, 6 figures, 12 tables.

  8. An Investigation of the Behavior of Solvent based Polycaprolactone ink for Material Jetting.

    Science.gov (United States)

    He, Yinfeng; Wildman, Ricky D; Tuck, Chris J; Christie, Steven D R; Edmondson, Steven

    2016-02-12

    An initial study of processing bioresorbable polycaprolactone (PCL) through material jetting was conducted using a Fujifilm Dimatix DMP-2830 material printer. The aim of this work was to investigate a potential solvent based method of jetting polycaprolactone. Several solvents were used to prepare a PCL solvent based ink and 1, 4-dioxane was chosen with the consideration of both solubility and safety. The morphology of PCL formed under different substrate temperatures, droplet spacings were investigated. Multi-layer PCL structures were printed and characterized. This work shows that biodegradable polycaprolactone can be processed through material jetting.

  9. The Rapid Synthesis of Schiff—Base withou Solvent under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    HaiJianYANG; WenHauSUN; 等

    2002-01-01

    A microwave-assisted preparation of a series of Schiff-base via efficient condensation of salicylaldehyde and aryl amines without solvent is described in high yield as well as environmental friendship reaction in organic synthesis.

  10. The Rapid Synthesis of Schiff-Base without Solvent under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A microwave-assisted preparation of a series of Schiff-base via efficient condensation of salicylaldehyde and aryl amines without solvent is described in high yield as well as environmental friendship reaction in organic synthesis.

  11. Synergetic Solvent Engineering of Film Nanomorphology to Enhance Planar Perylene Diimide-Based Organic Photovoltaics.

    Science.gov (United States)

    Wang, Jialin; Liang, Ziqi

    2016-08-31

    Solvent additive has proven as a useful protocol for improving the film nanomorphology of polymer donor (D): fullerene acceptor (A) blends in bulk heterojunction (BHJ) photovoltaic cells. By contrast, the effect of such solvent additive on nonfullerene BHJ cells based on perylene diimide acceptor, for instance, is less effective because of their highly planar structure and strong π-aggregation in solid state. Here we choose N,N'-bis(1-ethylpropyl)-perylene-3,4,9,10-tetracarboxylic diimide (PDI) and thieno[3,4-b]thiophene-alt-benzodithiophene (PTB7) as a model D:A blend system to investigate how solvent engineering strategy synergistically impacts the blend film nanomorphology. Based on the differences of solvent volatility and solubility, various host solvents-chloroform (CF) and chlorobenzene (CB) and solvent additives-chloronaphthalene (CN) and 1,8-diiodooctane (DIO) are selected for comparative studies. It is found that the π-aggregation of PDIs can be largely suppressed by using low-boiling point (Tb) CF solvent, yet enlarged by using high-Tb CB. Moreover, CN additive provides good solubility of PDI molecules and hence reduces large PDI aggregates in CB system, while DIO exhibiting poor solubility works oppositely. By contrast, DIO that presents larger Tb difference with CF prolongs the film-forming, which assists in optimizing the PDI aggregation and increases the intermixed PTB7:PDI phases more significantly than CN in CF system, yielding the finest phase-separation morphology and balanced charge mobility. Consequently, the inverted BHJ cells based on CF-processed PTB7:PDI blend film with 0.4 vol % DIO exhibit the highest PCE of 3.55% with a fill factor of 56%, both of which are among the best performance for such a paradigm PTB7:PDI blend-based BHJ cells.

  12. Steric and Solvent Effect in Dye-Sensitized Solar Cells Utilizing Phenothiazine-Based Dyes

    Directory of Open Access Journals (Sweden)

    Hany Kafafy

    2014-01-01

    Full Text Available Three phenothiazine-based dyes have been prepared and utilized as dye-sensitized solar cells (DSSCs. The effects of dye-adsorption solvent on the performances of dye-sensitized solar cells based on phenothiazine dyes were investigated in this study. The highest conversion efficiency of 3.78% was obtained using ethanol (EtOH and 2.53% for tetrahydrofuran (THF, respectively, as dye-adsorption solvents. Cell performance using EtOH as a dye-adsorption solvent showed relatively higher performance than that using THF. Electrochemical and photochemical tests of phenothiazine dyes in solution and adsorbed on the TiO2 surface showed less dye loading and coverage on the TiO2 surface during adsorption in the case of THF, which decreased the solar cell performance of the DSSC using THF as adsorption solvent compared with using EtOH as adsorption solvent. Meanwhile, the steric effect of phenothiazine-based (PT1–3 dyes was also investigated. Dye with longer and branched aliphatic chain in the order of PT1, PT2, and PT3 showed an increased resistance of the recombination reaction and electron lifetime, thereby increasing Voc and enhancing the overall cell performance because of the sterically hindered conformation of the phenothiazines.

  13. Conceptual design of a novel CO2 capture process based on precipitating amino acid solvents

    NARCIS (Netherlands)

    Sanchez Fernandez, E.; Heffernan, K.; Ham, L.V. van der; Linders, M.J.G.; Eggink, E.; Schrama, F.N.H.; Brilman, D.W.F.; Goetheer, E.L.V.; Vlugt, T.J.H.

    2013-01-01

    Amino acid salt based solvents can be used for CO2 removal from flue gas in a conventional absorption-thermal desorption process. Recently, new process concepts have been developed based on the precipitation of the amino acid zwitterion species during the absorption of CO2. In this work, a new conce

  14. Nano-structured gemini-based supramolecular solvent for the microextraction of cyhalothrin and fenvalerate.

    Science.gov (United States)

    Feizi, Neda; Yamini, Yadollah; Moradi, Morteza; Ebrahimpour, Behnam

    2016-09-01

    A novel supramolecular solvent-based microextraction followed by high-performance liquid chromatography with ultraviolet detection method has been developed for the extraction and determination of two pyrethroid analytes, cyhalothrin and fenvalerate, in water and soil samples. The liquid-liquid-phase separation of surfactants has been used in analytical extraction. The surfactant-rich phase is a nano-structured liquid, recently named as a supramolecular solvent, generated from the amphiphiles. The alkyl carboxylic acid based supramolecular solvents were introduced before. Coacervates made up of gemini surfactant, consisting of two amphiphilic moieties, were first used as solvent. The effective parameters on extraction (i.e., type of organic solvent, the amount of surfactant and volume of tetrahydrofuran, sample solution pH, salt addition, ultrasonic and centrifugation time) were investigated and optimized. Under the optimum conditions, preconcentration factors of 110 and 145 were obtained for the analytes. The linearity was 0.5-200.0 μg/L with the correlation of determination of (R(2) ) ≥ 0.9984. The limit of detection of the method was (S/N = 3) 0.2 μg/L, and precisions in the range of 6.3-10.3% (RSDs, n = 5) were obtained. This method has been successfully applied to analyze real samples, and good recoveries in the range of 101.2-108.8% were obtained.

  15. Effective Improvement of the Photovoltaic Performance of Carbon-Based Perovskite Solar Cells by Additional Solvents

    Institute of Scientific and Technical Information of China (English)

    Chenxi Zhang; Yudan Luo; Xiaohong Chen; Yiwei Chen; Zhuo Sun; Sumei Huang

    2016-01-01

    A solvent-assisted methodology has been developed to synthesize CH3NH3PbI3 perovskite absorber layers. It involved the use of a mixed solvent of CH3NH3I, PbI2,γ-butyrolactone, and dimethyl sulfoxide (DMSO) followed by the addition of chlorobenzene (CB). The method produced ultra-flat and dense perovskite capping layers atop mesoporous TiO2 films, enabling a remarkable improvement in the performance of free hole transport material (HTM) carbon elec-trode-based perovskite solar cells (PSCs). Toluene (TO) was also studied as an additional solvent for comparison. At the annealing temperature of 100 °C, the fabricated HTM-free PSCs based on drop-casting CB demonstrated power conversion efficiency (PCE) of 9.73%, which is 36 and 71% higher than those fabricated from the perovskite films using TO or without adding an extra solvent, respectively. The interaction between the PbI2–DMSO–CH3NH3I intermediate phase and the additional solvent was discussed. Furthermore, the influence of the annealing temperature on the absorber film formation, morphology, and crystalline structure was investigated and correlated with the photovoltaic performance. Highly efficient, simple, and stable HTM-free solar cells with a PCE of 11.44% were prepared utilizing the optimum perovskite absorbers annealed at 120 °C.

  16. A simple method for determining water content in organic solvents based on cobalt(II) complexes

    Institute of Scientific and Technical Information of China (English)

    Lin Zhou; Xiao Hua Liu; Hai Xin Bai; Hong Juan Wang

    2011-01-01

    A method to determine water content in organic solvents was developed based on the color change of cobalt(II) nitrate in different solvents. The color-change mechanism and optimal conditions for determining the water content were investigated. The results showed that there was a good linear relationships between the absorbance of cobalt(II) complexes in organic solvents and water contents with y in 0.9989~0.9994. This method has the advantages of low cost, good reproducibility, good sensitivity, simple in operation, fast in detection, friendly to the environment and no limitation on linear range for determining water content. It was used to determine water in samples with a satisfactory recovery in 97.81%~101.24%.

  17. SOLVENT-BASED TO WATERBASED ADHESIVE-COATED SUBSTRATE RETROFIT - VOLUME II: PROCESS OVERVIEW

    Science.gov (United States)

    This volume presents initial results of a study to identify the issues and barriers associated with retrofitting existing solvent-based equipment to accept waterbased adhesives as part of an EPA effort to improve equipment cleaning in the coated and laminated substrate manufactur...

  18. Predicting the acute neurotoxicity of diverse organic solvents using probabilistic neural networks based QSTR modeling approaches.

    Science.gov (United States)

    Basant, Nikita; Gupta, Shikha; Singh, Kunwar P

    2016-03-01

    Organic solvents are widely used chemicals and the neurotoxic properties of some are well established. In this study, we established nonlinear qualitative and quantitative structure-toxicity relationship (STR) models for predicting neurotoxic classes and neurotoxicity of structurally diverse solvents in rodent test species following OECD guideline principles for model development. Probabilistic neural network (PNN) based qualitative and generalized regression neural network (GRNN) based quantitative STR models were constructed using neurotoxicity data from rat and mouse studies. Further, interspecies correlation based quantitative activity-activity relationship (QAAR) and global QSTR models were also developed using the combined data set of both rodent species for predicting the neurotoxicity of solvents. The constructed models were validated through deriving several statistical coefficients for the test data and the prediction and generalization abilities of these models were evaluated. The qualitative STR models (rat and mouse) yielded classification accuracies of 92.86% in the test data sets, whereas, the quantitative STRs yielded correlation (R(2)) of >0.93 between the measured and model predicted toxicity values in both the test data (rat and mouse). The prediction accuracies of the QAAR (R(2) 0.859) and global STR (R(2) 0.945) models were comparable to those of the independent local STR models. The results suggest the ability of the developed QSTR models to reliably predict binary neurotoxicity classes and the endpoint neurotoxicities of the structurally diverse organic solvents.

  19. Alcohol based-deep eutectic solvent (DES) as an alternative green additive to increase rotenone yield

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Zetty Shafiqa; Hassan, Nur Hasyareeda; Zubairi, Saiful Irwan [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Deep eutectic solvents (DESs) are basically molten salts that interact by forming hydrogen bonds between two added components at a ratio where eutectic point reaches a melting point lower than that of each individual component. Their remarkable physicochemical properties (similar to ionic liquids) with remarkable green properties, low cost and easy handling make them a growing interest in many fields of research. Therefore, the objective of pursuing this study is to analyze the potential of alcohol-based DES as an extraction medium for rotenone extraction from Derris elliptica roots. DES was prepared by a combination of choline chloride, ChCl and 1, 4-butanediol at a ratio of 1/5. The structure of elucidation of DES was analyzed using FTIR, {sup 1}H-NMR and {sup 13}C-NMR. Normal soaking extraction (NSE) method was carried out for 14 hours using seven different types of solvent systems of (1) acetone; (2) methanol; (3) acetonitrile; (4) DES; (5) DES + methanol; (6) DES + acetonitrile; and (7) [BMIM] OTf + acetone. Next, the yield of rotenone, % (w/w), and its concentration (mg/ml) in dried roots were quantitatively determined by means of RP-HPLC. The results showed that a binary solvent system of [BMIM] OTf + acetone and DES + acetonitrile was the best solvent system combination as compared to other solvent systems. It contributed to the highest rotenone content of 0.84 ± 0.05% (w/w) (1.09 ± 0.06 mg/ml) and 0.84 ± 0.02% (w/w) (1.03 ± 0.01 mg/ml) after 14 hours of exhaustive extraction time. In conclusion, a combination of the DES with a selective organic solvent has been proven to have a similar potential and efficiency as of ILs in extracting bioactive constituents in the phytochemical extraction process.

  20. A green deep eutectic solvent-based aqueous two-phase system for protein extracting

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Kaijia; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Huang, Yanhua; Li, Na; Wen, Qian

    2015-03-15

    Highlights: • A strategy for the protein purification with a deep eutectic solvent(DES)-based aqueous two-phase system. • Choline chloride-glycerin DES was selected as the extraction solvent. • Bovine serum albumin and trypsin were used as the analytes. • Aggregation phenomenon was detected in the mechanism research. - Abstract: As a new type of green solvent, deep eutectic solvent (DES) has been applied for the extraction of proteins with an aqueous two-phase system (ATPS) in this work. Four kinds of choline chloride (ChCl)-based DESs were synthesized to extract bovine serum albumin (BSA), and ChCl-glycerol was selected as the suitable extraction solvent. Single factor experiments have been done to investigate the effects of the extraction process, including the amount of DES, the concentration of salt, the mass of protein, the shaking time, the temperature and PH value. Experimental results show 98.16% of the BSA could be extracted into the DES-rich phase in a single-step extraction under the optimized conditions. A high extraction efficiency of 94.36% was achieved, while the conditions were applied to the extraction of trypsin (Try). Precision, repeatability and stability experiments were studied and the relative standard deviations (RSD) of the extraction efficiency were 0.4246% (n = 3), 1.6057% (n = 3) and 1.6132% (n = 3), respectively. Conformation of BSA was not changed during the extraction process according to the investigation of UV–vis spectra, FT-IR spectra and CD spectra of BSA. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to explore the mechanism of the extraction. It turned out that the formation of DES–protein aggregates play a significant role in the separation process. All the results suggest that ChCl-based DES-ATPS are supposed to have the potential to provide new possibilities in the separation of proteins.

  1. Supramolecular solvent-based vortex-mixed microextraction: determination of glucocorticoids in water samples.

    Science.gov (United States)

    Qin, Hui; Qiu, Xiaoyan; Zhao, Jiao; Liu, Mousheng; Yang, Yaling

    2013-10-11

    Glucocorticoids contamination has become a big environmental issue in China and other developing countries, due to increasing needs in medical prescription and farming. However, no highly sensitive and precise methods have been reported to quantify glucocorticoids so far. In the past several years, supramolecular solvent-based vortex-mixed microextraction (SS-BVMME) has been shown to be effective. However, the mechanism of SS-BVMME is still unknown. In this report, a novel method has been proposed for rapid quantification of trace amount of glucocorticoids, beclomethasone dipropionate (BD), hydrocortisone butyrate (HB) and nandrolone phenylpropionate (NPP) in water samples from the Green Lake. This method is simple, safe and cost effective. It contains two steps: supramolecular solvent-based vortex-mixed microextraction (SS-BVMME) technique and high performance liquid chromatography (HPLC) analysis. First, ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) and n-butanol were mixed to form the supramolecular solvent. After mixing the supramolecular solvent with an aqueous sample to test, a homogenous mixture was formed immediately. BD, HB and NPP were then extracted based on their binding interactions, particularly hydrogen bond formed between their hydroxyl group and the supramolecular solvent. The overall process of sample preparation took only 20min and more than 5 samples could be simultaneously prepared. The minimum detectable concentrations of samples in this method were 0.09925, 0.5429 and 2.428ngmL(-1) for BD, HB and NPP, respectively. Product recoveries ranged from 88% to 103% with relative standard deviations from 0.6% to 4%. For the first time, we report that hydrogen bond plays a key role in SS-BVMME. We also improve the sensitivity significantly to quantify glucocorticoids, which may greatly benefit environmental safety management in China.

  2. Estudio de las Propiedades Anticorrosivas del Benzoato de Hierro (III en Pinturas Base Solvente Study of Anticorrosive Properties of the Iron (III Benzoate in Solvent Based Paints

    Directory of Open Access Journals (Sweden)

    Guillermo Blustein

    2006-01-01

    Full Text Available La acción inhibidora del benzoato de hierro en electrodos de acero SAE 1010 en contacto con una suspensión acuosa fue estudiada mediante ensayos electroquímicos. Paralelamente, la eficiencia anticorrosiva de este producto incorporado a cubiertas orgánicas base solvente fue evaluada mediante ensayos de envejecimiento acelerado (cámara de niebla salina y de humedad. La evolución del comportamiento protector de la cubierta aplicada sobre paneles de acero pintados e inmersos en una solución 0.5M de NaClO4 fue periódicamente monitoreada por espectroscopía de impedancia electroquímica. Los resultados obtenidos indican que las pinturas formuladas con benzoato férrico presentan una capacidad anticorrosiva comparable a las formuladas con fosfato de cinc.This study investigated the inhibitory action of iron benzoate on SAE 1010 steel electrodes in aqueous suspensions using electrochemical assays. The anticorrosive efficiency of this product added to organic solvent-based coatings was also evaluated by means of accelerated weathering tests (salt spray cabinet and humidity chamber. The evolution of the protective behavior of the coating applied on steel panels and immersed in 0.5M NaClO4 solution was periodically checked by electrochemical impedance spectroscopy. The results obtained showed that paints formulated with ferric benzoate provide anticorrosive protection similar to those formulated with zinc phosphate.

  3. Insights into the effects of solvent properties in graphene based electric double-layer capacitors with organic electrolytes

    Science.gov (United States)

    Zhang, Shuo; Bo, Zheng; Yang, Huachao; Yang, Jinyuan; Duan, Liangping; Yan, Jianhua; Cen, Kefa

    2016-12-01

    Organic electrolytes are widely used in electric double-layer capacitors (EDLCs). In this work, the microstructure of planar graphene-based EDLCs with different organic solvents are investigated with molecular dynamics simulations. Results show that an increase of solvent polarity could weaken the accumulation of counter-ions nearby the electrode surface, due to the screen of electrode charges and relatively lower ionic desolvation. It thus suggests that solvents with low polarity could be preferable to yield high EDL capacitance. Meanwhile, the significant effects of the size and structure of solvent molecules are reflected by non-electrostatic molecule-electrode interactions, further influencing the adsorption of solvent molecules on electrode surface. Compared with dimethyl carbonate, γ-butyrolactone, and propylene carbonate, acetonitrile with relatively small-size and linear structure owns weak non-electrostatic interactions, which favors the easy re-orientation of solvent molecules. Moreover, the shift of solvent orientation in surface layer, from parallel orientation to perpendicular orientation relative to the electrode surface, deciphers the solvent twin-peak behavior near negative electrode. The as-obtained insights into the roles of solvent properties on the interplays among particles and electrodes elucidate the solvent influences on the microstructure and capacitive behavior of EDLCs using organic electrolytes.

  4. Green Printing: Colorimetric and Densitometric Analysis of Solvent-Based and Vegetable Oil-Based Inks of Multicolor Offset Printing

    Science.gov (United States)

    Dharavath, H. Naik; Hahn, Kim

    2009-01-01

    The purpose of this study was to determine the differences in the measurable print attributes (Print Contrast and Dot Gain) and color gamut of solvent-based (SB) inks vs. vegetable oil-based (VO) inks of multicolor offset printing. The literature review revealed a lack of published research on this subject. VO inks tend to perform (color…

  5. Bridge- and Solvent-Mediated Intramolecular Electronic Communications in Ubiquinone-Based Biomolecular Wires

    Science.gov (United States)

    Liu, Xiao-Yuan; Ma, Wei; Zhou, Hao; Cao, Xiao-Ming; Long, Yi-Tao

    2015-05-01

    Intramolecular electronic communications of molecular wires play a crucial role for developing molecular devices. In the present work, we describe different degrees of intramolecular electronic communications in the redox processes of three ubiquinone-based biomolecular wires (Bis-CoQ0s) evaluated by electrochemistry and Density Functional Theory (DFT) methods in different solvents. We found that the bridges linkers have a significant effect on the electronic communications between the two peripheral ubiquinone moieties and solvents effects are limited and mostly depend on the nature of solvents. The DFT calculations for the first time indicate the intensity of the electronic communications during the redox processes rely on the molecular orbital elements VL for electron transfer (half of the energy splitting of the LUMO and LUMO+1), which is could be affected by the bridges linkers. The DFT calculations also demonstrates the effect of solvents on the latter two-electron transfer of Bis-CoQ0s is more significant than the former two electrons transfer as the observed electrochemical behaviors of three Bis-CoQ0s. In addition, the electrochemistry and theoretical calculations reveal the intramolecular electronic communications vary in the four-electron redox processes of three Bis-CoQ0s.

  6. CO{sub 2}-based supercritical fluids as environmentally-friendly processing solvents

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, J.B.; Davenhall, L.B.; Taylor, C.M.V.; Pierce, T. [Los Alamos National Lab., NM (United States). Physical Organic Chemistry Group; Tiefert, K. [Hewlett-Packard Co., Inc., Santa Clara, CA (United States)

    1999-03-01

    The production of integrated circuits involves a number of discrete steps that utilize hazardous or regulated solvents. Environmental, safety and health considerations associated with these chemicals have prompted a search for alternative, more environmentally benign, solvent systems. An emerging technology for conventional solvent replacement is the use of supercritical fluids based on carbon dioxide (CO{sub 2}). Supercritical CO{sub 2} (SCCO{sub 2}) is an excellent choice for IC manufacturing processes since it is non-toxic, non-flammable, inexpensive, and is compatible with all substrate and metallizations systems. Also, conditions of temperature and pressure needed to achieve the supercritical state are easily achievable with existing process equipment. The authors first describe the general properties of supercritical fluids, with particular emphasis on their application as alternative solvents. Next, they review some of the work which has been published involving the use of supercritical fluids, and particularly CO{sub 2}, as they may be applied to the various steps of IC manufacture, including wafer cleaning, thin film deposition, etching, photoresist stripping, and waste treatment. Next, they describe the research work conducted at Los Alamos, on behalf of Hewlett-Packard, on the use of SCCO{sub 2} in a specific step of the IC manufacturing process: the stripping of hard-baked photoresist.

  7. Flexibility and explicit solvent in molecular-dynamics-based docking of protein-glycosaminoglycan systems.

    Science.gov (United States)

    Samsonov, Sergey A; Gehrcke, Jan-Philip; Pisabarro, M Teresa

    2014-02-24

    We present Dynamic Molecular Docking (DMD), a novel targeted molecular dynamics-based protocol developed to address ligand and receptor flexibility as well as the inclusion of explicit solvent in local molecular docking. A class of ligands for which docking performance especially benefits from overcoming these challenges is the glycosaminoglycans (GAGs). GAGs are periodic, highly flexible, and negatively charged polysaccharides playing an important role in the extracellular matrix via interaction with proteins such as growth factors and chemokines. The goal of our work has been to develop a proof of concept for an MD-based docking approach and to analyze its applicability for protein-GAG systems. DMD exploits the electrostatics-driven attraction of a ligand to its receptor, treats both as entirely flexible, and considers solvent explicitly. We show that DMD has high predictive significance for systems dominated by electrostatic attraction and demonstrate its capability to reliably identify the receptor residues contributing most to binding.

  8. [Study on Enhancing Characteristic Vibration of the Molecular Vibration Spectrum for BDE-15 Based on Solvent Effect].

    Science.gov (United States)

    Jiang, Long; Meng, Chong; Li, Yu

    2015-12-01

    the similar change trend with Raman vibrational intensities. The spectra information of BDE-153, BDE-154, BDE-209 were used to authenticate the application on PBDEs of the analysis method above for BDE-15, obtaining the solvent effect index values on vibrational intensities on BDE-153, BDE-154, BDE-209 of alcohols, acetonitrile, dimethyl sulfoxide, nitrobenzene are all greater than 6 or 5, which indicate the enhancing vibrational intensities method can be used to identification research on PBDEs based on molecule vibrational spectra further.

  9. Solvent-based self-healing approaches for fiber-reinforced composites

    Science.gov (United States)

    Jones, Amanda R.

    Damage in composite materials spans many length scales and is often difficult to detect or costly to repair. The incorporation of self-healing functionality in composite materials has the potential to greatly extend material lifetime and reliability. Although there has been remarkable progress in self-healing polymers over the past decade, self-repair in fiber-reinforced composite materials presents significant technical challenges due to stringent manufacturing and performance requirements. For high performance, fiber-reinforced composites, the self-healing components need to survive high temperature processing, reside in matrix interstitial regions to retain a high fiber volume fraction, and have minimal impact on the mechanical properties of the host material. This dissertation explores several microencapsulated solvent-based self-healing approaches for fiber-reinforced composites at the fiber/ matrix interface size scale as well as matrix cracking. Systems are initially developed for room temperature cured epoxies/ glass fiber interfaces and successfully transitioned to carbon fibers and high temperature-cured, thermoplastic-toughened matrices. Full recovery of interfacial bond strength after complete fiber/matrix debonding is achieved with a microencapsulated solvent-based healing chemistry. The surface of a glass fiber is functionalized with microcapsules containing varying concentrations of reactive epoxy resin and ethyl phenyl acetate (EPA) solvent. Microbond specimens consisting of a single fiber and a microdroplet of epoxy are cured at 35°C, tested, and the interfacial shear strengths (IFSS) during the initial (virgin) debonding and subsequent healing events are measured. Debonding of the fiber/matrix interface ruptures the capsules, releasing resin and solvent into the crack plane. The solvent swells the matrix, initiating transport of residual amine functionality for further curing with the epoxy resin delivered to the crack plane. Using a resin-solvent

  10. Solution based zinc tin oxide TFTs: the dual role of the organic solvent

    Science.gov (United States)

    Salgueiro, Daniela; Kiazadeh, Asal; Branquinho, Rita; Santos, Lídia; Barquinha, Pedro; Martins, Rodrigo; Fortunato, Elvira

    2017-02-01

    Chemical solution deposition is a low cost, scalable and high performance technique to obtain metal oxide thin films. Recently, solution combustion synthesis has been introduced as a chemical route to reduce the processing temperature. This synthesis method takes advantage of the chemistry of the precursors as a source of energy for localized heating. According to the combustion chemistry some organic solvents can have a dual role in the reaction, acting both as solvent and fuel. In this work, we studied the role of 2-methoxyethanol in solution based synthesis of ZTO thin films and its influence on the performance of ZTO TFTs. The thermal behaviour of ZTO precursor solutions confirmed that 2-methoxyethanol acts simultaneously as a solvent and fuel, replacing the fuel function of urea. The electrical characterization of the solution based ZTO TFTs showed a slightly better performance and lower variability under positive gate bias stress when urea was not used as fuel, confirming that the excess fuel contributes negatively to the device operation and stability. Solution based ZTO TFTs demonstrated a low hysteresis (ΔV  =  -0.3 V) and a saturation mobility of 4-5 cm2 V-1 s-1.

  11. Towards safer sodium-ion batteries via organic solvent/ionic liquid based hybrid electrolytes

    Science.gov (United States)

    Monti, Damien; Ponrouch, Alexandre; Palacín, M. Rosa; Johansson, Patrik

    2016-08-01

    Hybrid electrolytes aimed at application in sodium-ion batteries (SIB) consisting of an organic solvent mixture (EC:PC) and different ionic liquids (ILs); EMImTFSI, BMImTFSI, and Pyr13TFSI, and with the NaTFSI salt providing the Na+ charge carriers have here been extensively studied. The physico-chemical and electrochemical characterisation includes ionic conductivity, viscosity, density, cation coordination and solvation, various safety measures, and electrochemical stability window (ESW). Hybrid electrolytes with 10-50% of IL content were found to have ionic conductivities on par with comparable organic solvent based electrolytes, but with highly enhanced safety properties. A systematic Raman spectroscopy study of the cation coordination and solvation before and after electrolyte safety tests by ignition suggest that IL cations and TFSI remain stable when ignited while organic solvents are consumed. Finally, the solid electrolyte interphase (SEI) formed when using hybrid electrolytes has both better mechanical and electrochemical stability than the SEI derived from pure IL based electrolytes. For a half-cell with a hard carbon (HC) electrode and a hybrid electrolyte with a composition of 0.8 m NaTFSI in EC0.45:PC0.45:Pyr13TFSI0.10 encouraging results were obtained for IL based electrolytes - ca. 182 mAhg-1 at C/10 over 40 cycles.

  12. Effects of metals on the transformation of hexabromocyclododecane (HBCD) in solvents: implications for solvent-based recycling of brominated flame retardants.

    Science.gov (United States)

    Zhong, Yin; Peng, Ping'an; Yu, Zhiqiang; Deng, Haopeng

    2010-09-01

    The management of electronic wastes (e-wastes) has become a global issue as it may release large quantities of hazardous materials such as heavy metals and brominated flame retardants (BFRs) to the environment. Solvent-based recycling is a newly developed, efficient and environmentally beneficial technology for the removal or recovery of BFRs from e-wastes. However, little is known about the behavior of BFRs in the solvents and to what extent they may be affected by co-existing heavy metals. This study quantified the rates of transformation of hexabromocyclododecane (HBCD), a widely used BFR, in the presence of different solvents (i.e. acetone, methanol or toluene) and metals (i.e. Ni, Cu, Zn, Fe or Al). Our experimental results showed that less than 20% of HBCD was transformed in all pure solvent systems within 24h at 50 degrees C. The presence of Ni greatly increased the transformation of HBCD (45-99%) in these solvent systems, whereas other metals had little or no effect on extraction process. The kinetics study showed that transformation of HBCD in Ni-containing systems followed pseudo-first-order kinetics and that the highest transformation rate constant (1.2+/-0.1h(-1)) of HBCD was recorded in the Ni+acetone system. The formation of HBr and pentabromocyclododecene in the acetone+Ni system suggested that transformation of HBCD proceeded via dehydrobromination. Collectively, these results indicated that acetone should not be applied in the recycling or extraction of HBCD from Ni-rich e-wastes, as debromination of HBCD may occur during these processes, even at mild extraction temperatures.

  13. Supercritical CO2-based solvents in next generation micro- electronics processing

    Institute of Scientific and Technical Information of China (English)

    ZHANG XiaoGang; Keith P.JOHNSTON

    2007-01-01

    Large amount of chemicals and highly purified-water are needed in microelectronic manufacture. The ability of solutions to penetrate tiny spaces will become significantly more challenging as the feature size of semiconductor devices decreases to nanoscale dimensions and the functional complexity of integrated circuitries (ICs) ever increases. Supercritical fluids (SCFs) possess a unique combination of properties (no surface tension and gas-like viscosity) that can potentially be exploited for application in microelectronics manufacturing and processing in response to needs for material-compatible cleaning systems, small-dimension developing solvents, and low chemical-use processes. Recent microelectronics processes for cleaning and rinsing of patterned porous low-k dielectrics and drying of photoresist in CO2-based solvents are the main focus of this review. Additional topics in supercritical fluid processing include spin coating of photoresists, development with nanoscale dimensions, metal deposition and silylation.

  14. Safe, high-energy supercapacitors based on solvent-free ionic liquid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Arbizzani, Catia; Biso, Maurizio; Cericola, Dario; Lazzari, Mariachiara; Soavi, Francesca; Mastragostino, Marina [University of Bologna, Dipartimento di Scienza dei Metalli, Elettrochimica e Tecniche Chimiche, via S. Donato 15, 40127 Bologna (Italy)

    2008-12-01

    Safety is the main concern for energy storage-system application in hybrid-electrical vehicles (HEVs) and ionic liquids (ILs) of low vapor pressure and high thermal stability represent a strategy to meet this key requisite. The use of solvent-free ILs in supercapacitors enables the high cell voltages required for increasing supercapacitor energy up to the values for power-assist application in HEVs. In order to exploit the wide electrochemical stability window of ILs, tailored electrode materials and cell configurations have to be used. The performance of asymmetric double-layer carbon supercapacitors (AEDLCs) and carbon/poly(3-methylthiophene) hybrid supercapacitors operating with different pyrrolidinium-based ILs are reported and compared. This study demonstrates that a design-optimized AEDLC operating with safe, solvent-free IL electrolyte meets cycling stability and the energy and power requisites for power-assisted HEVs at the investigated temperatures. (author)

  15. Dropwise additive manufacturing of pharmaceutical products for solvent-based dosage forms.

    Science.gov (United States)

    Hirshfield, Laura; Giridhar, Arun; Taylor, Lynne S; Harris, Michael T; Reklaitis, Gintaras V

    2014-02-01

    In recent years, the US Food and Drug Administration has encouraged pharmaceutical companies to develop more innovative and efficient manufacturing methods with improved online monitoring and control. Mini-manufacturing of medicine is one such method enabling the creation of individualized product forms for each patient. This work presents dropwise additive manufacturing of pharmaceutical products (DAMPP), an automated, controlled mini-manufacturing method that deposits active pharmaceutical ingredients (APIs) directly onto edible substrates using drop-on-demand (DoD) inkjet printing technology. The use of DoD technology allows for precise control over the material properties, drug solid state form, drop size, and drop dynamics and can be beneficial in the creation of high-potency drug forms, combination drugs with multiple APIs or individualized medicine products tailored to a specific patient. In this work, DAMPP was used to create dosage forms from solvent-based formulations consisting of API, polymer, and solvent carrier. The forms were then analyzed to determine the reproducibility of creating an on-target dosage form, the morphology of the API of the final form and the dissolution behavior of the drug over time. DAMPP is found to be a viable alternative to traditional mass-manufacturing methods for solvent-based oral dosage forms.

  16. Noncovalent interactions from electron density topology and solvent effects on spectral properties of Schiff bases

    Science.gov (United States)

    Gandhimathi, S.; Balakrishnan, C.; Theetharappan, M.; Neelakantan, M. A.; Venkataraman, R.

    2017-03-01

    Two Schiff bases were prepared by the condensation of o-allyl substituted 2,4-dihydroxy acetophenone with 1,2-diaminopropane (L1) and ethanediamine (L2) and characterized by elemental analysis, and ESI-MS, IR, UV-Vis, 1H and 13C NMR spectral techniques. The effect of solvents with respect to different polarities on UV-Vis and emission spectra of L1 and L2 was investigated at room temperature show that the compounds exist in keto and enol forms in solution and may be attributed to the intramolecular proton transfer in the ground state. The solute-solvent interactions, change in dipole moment and solvatochromic properties of the compounds were studied based on the solvent polarity parameters. For L1 and L2, the ground and excited state electronic structure calculations were carried out by DFT and TD-DFT at B3LYP/6-311G (d,p) level, respectively. The IR, NMR and electronic absorption spectra computed were compared with the experimental observations. The intramolecular charge transfer within the molecule is evidenced from the HOMO and LUMO energy levels and surface analysis. The noncovalent interactions like hydrogen bonding and van der Waals interactions were identified from the molecular geometry and electron localization function. These interactions in molecules have been studied by using reduced density gradient and graphed by Multiwfn.

  17. An acetylcholinesterase (AChE) biosensor with enhanced solvent resistance based on chitosan for the detection of pesticides.

    Science.gov (United States)

    Warner, John; Andreescu, Silvana

    2016-01-01

    Solvent tolerance of immobilized enzymes is important for many biosensing and biotechnological applications. In this paper we report an acetylcholinesterase (AChE) biosensor based on chitosan that exhibits high solvent resistance and enables sensitive detection of pesticides in presence of a high content of organic solvents. The solvent effect was established comparatively for the enzyme immobilized in chitosan and covalently cross-linked with glutaraldehyde. The activity of the immobilized AChE was dependent on the immobilization method and solvent type. The enzyme entrapped in chitosan fully conserved its activity in up to 25% methanol, 15% acetonitrile and 100% cyclohexane while the enzyme cross-linked with glutaraldehyde gradually lost its activity starting at 5% acetonitrile and methanol, and showed variable levels in cyclohexane. The detection limits of the biosensor for paraoxon were: 7.5 nM in 25% methanol, 100 nM in 15% acetonitrile and 2.5 μM in 100% cyclohexane. This study demonstrates that chitosan provides an excellent immobilization environment for AChE biosensors designed to operate in environments containing high amounts of organic solvents. It also highlights the effect of the immobilization material and solvent type on enzyme stability. These findings can enable future selection of the immobilization matrix and solvent type for the development of organic phase enzyme based systems.

  18. Solvent Optimization for Efficient Enzymatic Monoacylglycerol Production Based on a Glycerolysis Reaction

    DEFF Research Database (Denmark)

    Damstrup, Marianne; Jensen, Tine; Sparsø, Flemming V.;

    2005-01-01

    This study was aimed at screening solvent systems of varying polarities to identify suitable solvents for efficient and practical enzymatic glycerolysis. Several pure solvents and solvent mixtures were screened in a batch reaction system consisting of glycerol, sunflower oil, and Novozymo (R) 435...

  19. Preferential solvation and solvation shell composition of free base and protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin in aqueous organic mixed solvents.

    Science.gov (United States)

    Farajtabar, Ali; Jaberi, Fatemeh; Gharib, Farrokh

    2011-12-01

    The solvatochromic properties of the free base and the protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) were studied in pure water, methanol, ethanol (protic solvents), dimethylsulfoxide, DMSO, (non-protic solvent), and their corresponding aqueous-organic binary mixed solvents. The correlation of the empirical solvent polarity scale (E(T)) values of TPPS with composition of the solvents was analyzed by the solvent exchange model of Bosch and Roses to clarify the preferential solvation of the probe dyes in the binary mixed solvents. The solvation shell composition and the synergistic effects in preferential solvation of the solute dyes were investigated in terms of both solvent-solvent and solute-solvent interactions and also, the local mole fraction of each solvent composition was calculated in cybotactic region of the probe. The effective mole fraction variation may provide significant physico-chemical insights in the microscopic and molecular level of interactions between TPPS species and the solvent components and therefore, can be used to interpret the solvent effect on kinetics and thermodynamics of TPPS. The obtained results from the preferential solvation and solvent-solvent interactions have been successfully applied to explain the variation of equilibrium behavior of protonation of TPPS occurring in aqueous organic mixed solvents of methanol, ethanol and DMSO.

  20. Preferential solvation and solvation shell composition of free base and protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin in aqueous organic mixed solvents

    Science.gov (United States)

    Farajtabar, Ali; Jaberi, Fatemeh; Gharib, Farrokh

    2011-12-01

    The solvatochromic properties of the free base and the protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) were studied in pure water, methanol, ethanol (protic solvents), dimethylsulfoxide, DMSO, (non-protic solvent), and their corresponding aqueous-organic binary mixed solvents. The correlation of the empirical solvent polarity scale ( ET) values of TPPS with composition of the solvents was analyzed by the solvent exchange model of Bosch and Roses to clarify the preferential solvation of the probe dyes in the binary mixed solvents. The solvation shell composition and the synergistic effects in preferential solvation of the solute dyes were investigated in terms of both solvent-solvent and solute-solvent interactions and also, the local mole fraction of each solvent composition was calculated in cybotactic region of the probe. The effective mole fraction variation may provide significant physico-chemical insights in the microscopic and molecular level of interactions between TPPS species and the solvent components and therefore, can be used to interpret the solvent effect on kinetics and thermodynamics of TPPS. The obtained results from the preferential solvation and solvent-solvent interactions have been successfully applied to explain the variation of equilibrium behavior of protonation of TPPS occurring in aqueous organic mixed solvents of methanol, ethanol and DMSO.

  1. Solvent-free Synthesis of Flavanone over New Hybrid Mesoporous Base Catalysts

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; NIU Xiao-di; ZHAO Min; XIAO Xue-bin; WANG Hong-su; WANG Zhong-dong

    2011-01-01

    Benzyl and anthracenemethyl groups were respectively bonded to the N atoms of 3-aminopropyl functionalized mesoporous SBA-15(APS-SBA-15) to obtain two new base catalysts over which the condensation reaction of benzaldehyde and 2′-hydroxyacetophenone was studied.Good catalytic activities and high selectivities for flavanones were obtained in solvent-free reactions,which is attributed to the effect of benzyl and anthracenemetyl groups on the base sites of catalysts and the steric hindrance of futher reaction of flavanone with benzaldehyde.

  2. Efficient inverted organic light-emitting devices by amine-based solvent treatment (Presentation Recording)

    Science.gov (United States)

    Song, Myoung Hoon; Choi, Kyoung-Jin; Jung, Eui Dae

    2015-10-01

    The efficiency of inverted polymer light-emitting diodes (iPLEDs) were remarkably enhanced by introducing spontaneously formed ripple-shaped nanostructure of ZnO (ZnO-R) and amine-based polar solvent treatment using 2-methoxyethanol and ethanolamine (2-ME+EA) co-solvents on ZnO-R. The ripple-shape nanostructure of ZnO layer fabricated by solution process with optimal rate of annealing temperature improves the extraction of wave guide modes inside the device structure, and 2-ME+EA interlayer enhances the electron injection and hole blocking and reduces exciton quenching between polar solvent treated ZnO-R and emissive layer. As a result, our optimized iPLEDs show the luminous efficiency (LE) of 61.6 cd A-1, power efficiency (PE) of 19.4 lm W-1 and external quantum efficiency (EQE) of 17.8 %. This method provides a promising method, and opens new possibilities for not only organic light-emitting diodes (OLEDs) but also other organic optoelectronic devices such as organic photovoltaics, organic thin film transistors, and electrically driven organic diode laser.

  3. Computational prediction of octanol-water partition coefficient based on the extended solvent-contact model.

    Science.gov (United States)

    Kim, Taeho; Park, Hwangseo

    2015-07-01

    The logarithm of 1-octanol/water partition coefficient (LogP) is one of the most important molecular design parameters in drug discovery. Assuming that LogP can be calculated from the difference between the solvation free energy of a molecule in water and that in 1-octanol, we propose a method for predicting the molecular LogP values based on the extended solvent-contact model. To obtain the molecular solvation free energy data for the two solvents, a proper potential energy function was defined for each solvent with respect to atomic distributions and three kinds of atomic parameters. Total 205 atomic parameters were optimized with the standard genetic algorithm using the training set consisting of 139 organic molecules with varying shapes and functional groups. The LogP values estimated with the two optimized solvation free energy functions compared reasonably well with the experimental results with the associated squared correlation coefficient and root mean square error of 0.824 and 0.697, respectively. Besides the prediction accuracy, the present method has the merit in practical applications because molecular LogP values can be computed straightforwardly from the simple potential energy functions without the need to calculate various molecular descriptors. The methods for enhancing the accuracy of the present prediction model are also discussed.

  4. SOLVENT-BASED TO WATERBASED ADHESIVE-COATED SUBSTRATE RETROFIT - VOLUME III: LABEL MANUFACTURING CASE STUDY: NASHUA CORPORATION

    Science.gov (United States)

    This volume discusses Nashua Corporation's Omaha facility, a label and label stock manufacturing facility that no longer uses solvent-based adhesives. Information obtained includes issues related to the technical, economic, and environmental barriers and opportunities associated ...

  5. Pulmonary Toxicity of Perfluorinated Silane-Based Nanofilm Spray Products: Solvent Dependency

    DEFF Research Database (Denmark)

    Nørgaard, Asger Wisti; Hansen, Jitka S.; Sørli, Jorid Birkelund;

    2014-01-01

    A number of cases of pulmonary injury by use of aerosolized surface coating products have been reported worldwide. The aerosol from a commercial alcohol-based nanofilm product (NFP) for coating of nonabsorbing surfaces was found to induce severe lung damage in a recent mouse bioassay. The NFP...... volume was observed after 13 and 9min, respectively; thus, the tidal volume was affected by increase of the chain length. This was confirmed in vitro by investigating lung surfactant function after addition of POTS in different solvents. The addition of vaporized methanol, 2-propanol, or acetone...

  6. Comparative in vitro study of cholinium-based ionic liquids and deep eutectic solvents toward fish cell line.

    Science.gov (United States)

    Radošević, Kristina; Železnjak, Jelena; Cvjetko Bubalo, Marina; Radojčić Redovniković, Ivana; Slivac, Igor; Gaurina Srček, Višnja

    2016-09-01

    With the advent of ionic liquids, much was expected concerning their applicability as an alternative to organic solvents in the chemical technology and biotechnology fields. However, the most studied and commonly used ionic liquids based on imidazolium and pyridinium were found not to be as environmentally friendly as it was first expected. Therefore, a new generation of alternative solvents named natural ionic liquids and deep eutectic solvents, composed of natural and/or renewable compounds, have come into focus in recent years. Since the number of newly synthesized chemicals increases yearly, simple and reliable methods for their ecotoxicological assessment are necessary. Permanent fish cell lines can serve as a test system for the evaluation of a chemical's cytotoxicity. This paper presents research results on the cytotoxic effects on Channel Catfish Ovary (CCO) cell line induced by fifteen cholinium-based ionic liquids and deep eutectic solvents. Based on the decrease in cell viability, the most obvious toxic effect on CCO cells was caused by ionic liquid choline oxalate, while other solvents tested exhibited low cytotoxicity. Therefore, we can conclude that cholinium-based ionic liquids and deep eutectic solvents are comparatively less toxic to CCO cells than conventional ionic liquids.

  7. Gels and lyotropic liquid crystals: using an imidazolium-based catanionic surfactant in binary solvents.

    Science.gov (United States)

    Cheng, Ni; Hu, Qiongzheng; Bi, Yanhui; Xu, Wenwen; Gong, Yanjun; Yu, Li

    2014-08-01

    The self-assembly behavior of an imidazolium-based catanionic surfactant, 1-butyl-3-methylimidazolium dodecylsulfate ([C4mim][C12H25SO4]), was investigated in water-ethylammonium nitrate (EAN) mixed solvents with different volume ratios. It is particular interesting that this simple surfactant could not only form lyotropic liquid crystals (LLC) with multimesophases, i.e., normal hexagonal (H1), lamellar liquid crystal (Lα), and reverse bicontinuous cubic phase (V2), in the water-rich environment but also act as an efficient low-molecular-weight gelator (LMWG) which gelated EAN-abundant binary media in a broad concentration range. The peculiar nanodisk cluster morphology of gels composed of similar bilayer units was first observed. FT-IR spectra and density functional theory (DFT) calculations reveal that strong H bonding and electrostatic interactions between EAN and the headgroups of [C4mim][C12H25SO4] are primarily responsible for gelation. The self-assembled gels displayed excellent mechanical strength and a thermoreversible sol-gel transition. It is for the first time that a rich variety of controllable ordered aggregates could be observed only by simply modulating the concentration of a single imidazolium-based catanionic surfactant or the ratio of mixed solvents. This environmentally friendly system is expected to have broad applications in various fields, such as materials science, drug delivery systems, and supramolecular chemistry.

  8. Solvent stimulated actuation of polyurethane-based shape memory polymer foams using dimethyl sulfoxide and ethanol

    Science.gov (United States)

    Boyle, A. J.; Weems, A. C.; Hasan, S. M.; Nash, L. D.; Monroe, M. B. B.; Maitland, D. J.

    2016-07-01

    Solvent exposure has been investigated to trigger actuation of shape memory polymers (SMPs) as an alternative to direct heating. This study aimed to investigate the feasibility of using dimethyl sulfoxide (DMSO) and ethanol (EtOH) to stimulate polyurethane-based SMP foam actuation and the required solvent concentrations in water for rapid actuation of hydrophobic SMP foams. SMP foams exhibited decreased T g when submerged in DMSO and EtOH when compared to water submersion. Kinetic DMA experiments showed minimal or no relaxation for all SMP foams in water within 30 min, while SMP foams submerged in EtOH exhibited rapid relaxation within 1 min of submersion. SMP foams expanded rapidly in high concentrations of DMSO and EtOH solutions, where complete recovery over 30 min was observed in DMSO concentrations greater than 90% and in EtOH concentrations greater than 20%. This study demonstrates that both DMSO and EtOH are effective at triggering volume recovery of polyurethane-based SMP foams, including in aqueous environments, and provides promise for use of this actuation technique in various applications.

  9. Supramolecular solvent-based hollow fiber liquid phase microextraction of benzodiazepines.

    Science.gov (United States)

    Rezaei, Fatemeh; Yamini, Yadollah; Moradi, Morteza; Daraei, Bahram

    2013-12-04

    A new, efficient, and environmental friendly hollow fiber liquid phase microextraction (HF-LPME) method based on supramolecular solvents was developed for extraction of five benzodiazepine drugs. The supramolecular solvent was produced from coacervation of decanoic acid aqueous vesicles in the presence of tetrabutylammonium (Bu4N(+)). In this work, benzodiazepines were extracted from aqueous samples into a supramolecular solvent impregnated in the wall pores and also filled inside the porous polypropylene hollow fiber membrane. The driving forces for the extraction were hydrophobic, hydrogen bonding, and π-cation interactions between the analytes and the vesicular aggregates. High-performance liquid chromatography with photodiode array detection (HPLC-DAD) was applied for separation and determination of the drugs. Several parameters affecting the extraction efficiency including pH, hollow fiber length, ionic strength, stirring rate, and extraction time were investigated and optimized. Under the optimal conditions, the preconcentration factors were obtained in the range of 112-198. Linearity of the method was determined to be in the range of 1.0-200.0 μg L(-1) for diazepam and 2.0-200.0 μg L(-1) for other analytes with coefficient of determination (R(2)) ranging from 0.9954 to 0.9993. The limits of detection for the target benzodiazepines were in the range of 0.5-0.7 μg L(-1). The method was successfully applied for extraction and determination of the drugs in water, fruit juice, plasma and urine samples and relative recoveries of the compounds studied were in the range of 90.0-98.8%.

  10. Response Surface Optimization of Rotenone Using Natural Alcohol-Based Deep Eutectic Solvent as Additive in the Extraction Medium Cocktail

    Directory of Open Access Journals (Sweden)

    Zetty Shafiqa Othman

    2017-01-01

    Full Text Available Rotenone is a biopesticide with an amazing effect on aquatic life and insect pests. In Asia, it can be isolated from Derris species roots (Derris elliptica and Derris malaccensis. The previous study revealed the comparable efficiency of alcohol-based deep eutectic solvent (DES in extracting a high yield of rotenone (isoflavonoid to binary ionic liquid solvent system ([BMIM]OTf and organic solvent (acetone. Therefore, this study intends to analyze the optimum parameters (solvent ratio, extraction time, and agitation rate in extracting the highest yield of rotenone extract at a much lower cost and in a more environmental friendly method by using response surface methodology (RSM based on central composite rotatable design (CCRD. By using RSM, linear polynomial equations were obtained for predicting the concentration and yield of rotenone extracted. The verification experiment confirmed the validity of both of the predicted models. The results revealed that the optimum conditions for solvent ratio, extraction time, and agitation rate were 2 : 8 (DES : acetonitrile, 19.34 hours, and 199.32 rpm, respectively. At the optimum condition of the rotenone extraction process using DES binary solvent system, this resulted in a 3.5-fold increase in a rotenone concentration of 0.49 ± 0.07 mg/ml and yield of 0.35 ± 0.06 (%, w/w as compared to the control extract (acetonitrile only. In fact, the rotenone concentration and yield were significantly influenced by binary solvent ratio and extraction time (P<0.05 but not by means of agitation rate. For that reason, the optimal extraction condition using alcohol-based deep eutectic solvent (DES as a green additive in the extraction medium cocktail has increased the potential of enhancing the rotenone concentration and yield extracted.

  11. Enhanced removal of lead from contaminated soil by polyol-based deep eutectic solvents and saponin

    Science.gov (United States)

    Mukhopadhyay, Soumyadeep; Mukherjee, Sumona; Hayyan, Adeeb; Hayyan, Maan; Hashim, Mohd Ali; Sen Gupta, Bhaskar

    2016-11-01

    Deep eutectic solvents (DESs) are a class of green solvents analogous to ionic liquids, but less costly and easier to prepare. The objective of this study is to remove lead (Pb) from a contaminated soil by using polyol based DESs mixed with a natural surfactant saponin for the first time. The DESs used in this study were prepared by mixing a quaternary ammonium salt choline chloride with polyols e.g. glycerol and ethylene glycol. A natural surfactant saponin obtained from soapnut fruit pericarp, was mixed with DESs to boost their efficiency. The DESs on their own did not perform satisfactory due to higher pH; however, they improved the performance of soapnut by up to 100%. Pb removal from contaminated soil using mixture of 40% DES-Gly and 1% saponin and mixture of 10% DES-Gly and 2% saponin were above 72% XRD and SEM studies did not detect any major corrosion in the soil texture. The environmental friendliness of both DESs and saponin and their affordable costs merit thorough investigation of their potential as soil washing agents.

  12. DFT-based QSAR and QSPR models of several cis-platinum complexes: solvent effect.

    Science.gov (United States)

    Sarmah, Pubalee; Deka, Ramesh C

    2009-06-01

    Cytotoxic activities of cis-platinum complexes against parental and resistant ovarian cancer cell lines were investigated by quantitative structure-activity relationship (QSAR) analysis using density functional theory (DFT) based descriptors. The calculated parameters were found to increase the predictability of each QSAR model with incorporation of solvent effects indicating its importance in studying biological activity. Given the importance of logarithmic n-octanol/water partition coefficient (log P(o/w)) in drug metabolism and cellular uptake, we modeled the log P(o/w) of 24 platinum complexes with different leaving and carrier ligands by the quantitative structure-property relationship (QSPR) analysis against five different concentrations of MeOH using DFT and molecular mechanics derived descriptors. The log P(o/w) values of an additional set of 20 platinum complexes were also modeled with the same descriptors. We investigated the predictability of the model by calculating log P(o/w) of four compounds in the test set and found their predicted values to be in good agreement with the experimental values. The QSPR analyses performed on 24 complexes, combining the training and test sets, also provided significant values for the statistical parameters. The solvent medium played an important role in QSPR analysis by increasing the internal predictive ability of the models.

  13. Alternative Single-Solvent Electrolytes Based on Cyanoesters for Safer Lithium-Ion Batteries.

    Science.gov (United States)

    Brox, Sebastian; Röser, Stephan; Husch, Tamara; Hildebrand, Stephan; Fromm, Olga; Korth, Martin; Winter, Martin; Cekic-Laskovic, Isidora

    2016-07-07

    To identify alternative single-solvent-based electrolytes for application in lithium-ion batteries (LIBs), adequate computational methods were applied to screen specified physicochemical and electrochemical properties of new cyanoester-based compounds. Out of 2747 possible target compounds, two promising candidates and two structurally equivalent components were chosen. A constructive selection process including evaluation of basic physicochemical properties as well assessing the compatibility towards graphitic anodes was initiated to identify the most promising candidates. With addition of a film-forming additive in a low concentration, the most promising candidate showed an adequate long-term cycling stability with LiNi1/3 Mn1/3 Co1/3 O2 [NMC(111)] in a full-cell setup using graphite as anode material. The main advantages of the new electrolyte formulation are related to its good thermal behavior, especially with regard to safety in combination with satisfying electrochemical performance.

  14. Solvent selection methodology for pharmaceutical processes: Solvent swap

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; Kumar Tula, Anjan; Gani, Rafiqul

    2016-01-01

    A method for the selection of appropriate solvents for the solvent swap task in pharmaceutical processes has been developed. This solvent swap method is based on the solvent selection method of Gani et al. (2006) and considers additional selection criteria such as boiling point difference, volati...

  15. Imidazole-based deep eutectic solvents for starch dissolution and plasticization.

    Science.gov (United States)

    Zdanowicz, Magdalena; Spychaj, Tadeusz; Mąka, Honorata

    2016-04-20

    Potato starch and high-amylose starch were treated with imidazole-based deep eutectic solvents (DESs) as dissolution and plasticization media. Beside imidazole (IM) for two-component DESs preparation choline chloride (CC), glycerol (G) or carboxylic acids (citric or malic) were used. An influence of water content in starch (as well as an extra water in the starch/DES system) on polymer dissolution and plasticization processes was investigated. Dissolution and gelatinization of starch in DESs were followed via DSC and laser scanning microscopy. A rheometric characteristics revealed an influence of starch/DES system storage time on the plasticization process. The tendency to recrystallization of compression-molded-starch films was evaluated using XRD technique. High dissolution and plasticization effectiveness of CC/IM and G/IM and a low tendency to film retrogradation of thermoplasticized starch were noted.

  16. Roles of Poly(propylene Glycol) During Solvent-Based Lamination of Ceramic Green Tapes

    Science.gov (United States)

    Suppakarn, Nitinat; Ishida, Hatsuo; Cawley, James D.; Levine, Stanley R. (Technical Monitor)

    2000-01-01

    Solvent lamination for alumina green tapes is readily accomplished using a mixture of ethanol, toluene and poly(propylene glycol). After lamination, the PPG is clearly present as a discrete film at the interface between the laminated tapes. This condition, however, does not generate delamination during firing. Systematic sets of experiments are undertaken to determine the role of PPG in the lamination process and, specifically, the mechanism by which it is redistributed during subsequent processing. PPG slowly diffuses through the organic binder film at room temperature. The PPG diffusion rapidly increases as temperature is increased to 80 C. The key to the efficiency of adhesives during green-tape lamination is mutual solubility of the nonvolatile component of the glue and the base polymeric binder.

  17. In Vitro and In Vivo toxicity profiling of ammonium-based deep eutectic solvents.

    Science.gov (United States)

    Hayyan, Maan; Looi, Chung Yeng; Hayyan, Adeeb; Wong, Won Fen; Hashim, Mohd Ali

    2015-01-01

    The cytotoxic potential of ammonium-based deep eutectic solvents (DESs) with four hydrogen bond donors, namely glycerine (Gl), ethylene glycol (EG), triethylene glycol (TEG) and urea (U) were investigated. The toxicity of DESs was examined using In Vitro cell lines and In Vivo animal model. IC50 and selectivity index were determined for the DESs, their individual components and their combinations as aqueous solutions for comparison purposes. The cytotoxicity effect of DESs varied depending on cell lines. The IC50 for the GlDES, EGDES, UDES and TEGDES followed the sequence of TEGDESIn Vivo toxicity profiles of DESs were being demonstrated, raising the toxicity issue of these neoteric mixtures and their potential applicability to be used for therapeutic purposes.

  18. Solvent based hydrogen bonding: impact on poly(3-hexylthiophene) nanoscale morphology and charge transport characteristics.

    Science.gov (United States)

    Chang, Mincheol; Choi, Dalsu; Fu, Boyi; Reichmanis, Elsa

    2013-06-25

    We demonstrate that supramolecular assembly and subsequent enhancement of charge transport characteristics of conjugated polymers can be facilitated simply by adding small amounts of a more volatile poor solvent, which can hydrogen bond with the majority solvent. Addition of up to 2 vol % acetone to a precursor solution of poly(3-hexylthiophene) (P3HT) in chloroform leads to approximately a 4-fold increase in P3HT field-effect mobility. The improvement is associated with hydrogen bonding interactions between acetone and chloroform which decrease the evaporation rate of the mixed solvent. P3HT is less soluble in the binary solvent than in the more readily vaporized chloroform component, and this characteristic enables the supramolecular assembly of P3HT chains at the nanoscale. Two-dimensional molecular ordering of the polymer film was controlled by varying the quantity of poor solvent added to the precursor solution, and the correlation between field-effect mobility and molecular ordering was investigated. Hansen solubility parameters were used to systematically understand how the solvent mixture enhances the alignment and assembly of polymer chains and influences subsequent thin film properties. The value of the relative energy difference (RED) of the solvent with respect to P3HT increased from less than 1 to more than 1 during film formation, which indicates that the solvent characteristics are initially those of a good solvent but transform into those of a poor dissolution medium. A mechanistic illustration of the molecular ordering process during film formation is postulated.

  19. Multiphase enantioselective Kharasch-Sosnovsky allylic oxidation based on neoteric solvents and copper complexes of ditopic ligands.

    Science.gov (United States)

    Aldea, Luis; García, José I; Mayoral, José A

    2012-07-21

    Recoverable multiphase enantioselective catalytic systems for the Kharasch-Sosnovsky oxidation of cycloalkenes with tert-butyl peroxybenzoate are described, based on the use of [BMIM][PF(6)] and a new solvent derived from glycerol as the catalyst reservoir phases, and chiral copper complexes with different ligands from the bis(oxazoline) family. The best results are obtained with the glycerol-derived solvent and a recently described azabisoxazoline-based ditopic ligand, allowing up to four uses of the catalytic phase with good results.

  20. Quick supramolecular solvent-based microextraction for quantification of low curcuminoid content in food.

    Science.gov (United States)

    Caballero-Casero, Noelia; Ocak, Miraç; Ocak, Ümmüham; Rubio, Soledad

    2014-03-01

    There is a need to monitor the consumption of curcuminoids, an EU-permitted natural colour in food, to ensure that acceptable daily intakes are not exceeded, especially by young children. This paper describes a sensitive method able to quantify low contents of curcumin (CUR), demethoxycurcumin (DMC) and bis-demethoxycurcumin (BDMC) in foodstuffs. The method was based on a single-step extraction by use of a supramolecular solvent (SUPRAS) made up of reverse aggregates of decanoic acid, and direct analysis of the extract by use of liquid chromatography-photodiode array (PDA) detection. The extraction involved the stirring of 200 mg foodstuff with 600 μL SUPRAS for 15 min. No cleanup or concentration of the extracts was required. Curcuminoid solubilisation occurred via dispersion and hydrogen bonding. The method was used for the determination of curcuminoids in different types of foodstuff (snack, gelatine, yoghurt, mayonnaise, butter, candy and fish products) that encompassed a wide range of protein, fat, carbohydrate, sugar and water contents (0.85-11.04, 0-81.11, 0.06-75, 0.06-79.48, and 10.08-85.10 g, respectively, in each 100 g of food). Method quantification limits for the foodstuffs analysed were in the ranges 2.9-7.7, 2.8-11.2 and 3.3-9.0 μg kg(-1) for CUR, DMC and BDMC, respectively. The concentrations of curcuminoids detected in the foodstuffs and the recoveries obtained from fortified samples were in the ranges ND-284, ND-201 and ND-61.3 μg kg(-1), and 82-106, 89-106 and 90-102 %, for CUR, DMC and BDMC, respectively. The relative standard deviations were in the range 2-7 %. This method enabled quick and simple microextraction of curcuminoids with minimal solvent consumption, while delivering accurate and precise data.

  1. 1-Butyl-3-Methyl Imidazolium-based Ionic Liquids Explored as Potential Solvents for Lipid Processing

    Science.gov (United States)

    Due to global environmental concerns, there is increasing interest in replacing the volatile solvents currently used to process commodity plant lipids. Room-temperature molten salts are one type of media receiving great attention as a possible replacement of the typical organic solvent. Molten sal...

  2. Develop and test a solvent accessible surface area-based model in conformational entropy calculations.

    Science.gov (United States)

    Wang, Junmei; Hou, Tingjun

    2012-05-25

    It is of great interest in modern drug design to accurately calculate the free energies of protein-ligand or nucleic acid-ligand binding. MM-PBSA (molecular mechanics Poisson-Boltzmann surface area) and MM-GBSA (molecular mechanics generalized Born surface area) have gained popularity in this field. For both methods, the conformational entropy, which is usually calculated through normal-mode analysis (NMA), is needed to calculate the absolute binding free energies. Unfortunately, NMA is computationally demanding and becomes a bottleneck of the MM-PB/GBSA-NMA methods. In this work, we have developed a fast approach to estimate the conformational entropy based upon solvent accessible surface area calculations. In our approach, the conformational entropy of a molecule, S, can be obtained by summing up the contributions of all atoms, no matter they are buried or exposed. Each atom has two types of surface areas, solvent accessible surface area (SAS) and buried SAS (BSAS). The two types of surface areas are weighted to estimate the contribution of an atom to S. Atoms having the same atom type share the same weight and a general parameter k is applied to balance the contributions of the two types of surface areas. This entropy model was parametrized using a large set of small molecules for which their conformational entropies were calculated at the B3LYP/6-31G* level taking the solvent effect into account. The weighted solvent accessible surface area (WSAS) model was extensively evaluated in three tests. For convenience, TS values, the product of temperature T and conformational entropy S, were calculated in those tests. T was always set to 298.15 K through the text. First of all, good correlations were achieved between WSAS TS and NMA TS for 44 protein or nucleic acid systems sampled with molecular dynamics simulations (10 snapshots were collected for postentropy calculations): the mean correlation coefficient squares (R²) was 0.56. As to the 20 complexes, the TS

  3. Characterization of solvents containing CyMe4-BTPhen in selected cyclohexanone-based diluents after irradiation by accelerated electrons

    Directory of Open Access Journals (Sweden)

    Distler Petr

    2015-12-01

    Full Text Available Radiation stability of CyMe4-BTPhen was examined in systems with three selected cyclohexanone-based diluents. Accelerated electrons were used as a source of ionizing radiation. The CyMe4-BTPhen radiation degradation identification and characterization of the degradation products were performed by high performance liquid chromatography (HPLC and mass spectrometry (MS analyses. Residual concentrations of tested ligand were determined. Moreover, extraction properties of the solvents irradiated at two different doses were compared with the extraction properties of non-irradiated solvents to estimate the influence of the presence of degradation products in the organic phase.

  4. Polarizable continuum model study on the solvent effect of polymer matrix in poly(ethylene oxide)-based solid electrolyte.

    Science.gov (United States)

    Eilmes, Andrzej; Kubisiak, Piotr

    2008-09-18

    The Polarizable Continuum Model has been used to study the effect of polymer matrix on Li (+) and Mg (2+) complexation in poly(ethylene oxide)-based solid electrolyte. Structures of complexes, stabilization energies, and vibrational frequencies are compared with corresponding vacuum values. The solvent effect of the polymer decreases with increasing cation coordination number. Optimized complex geometries do not differ significantly compared to vacuum calculations. Calculated shifts in vibrational frequencies depend on the complex structure; for hexacoordinated ion most frequencies are slightly red-shifted. The most important effect is the decrease of differences between relative stabilities of different structures in the solvent.

  5. Process to prepare stable trifluorostyrene containing compounds grafted to base polymers using a solvent/water mixture

    Science.gov (United States)

    Roelofs, Mark Gerrit; Yang, Zhen-Yu; Han, Amy Qi

    2010-06-15

    A fluorinated ion exchange polymer is prepared by grafting at least one grafting monomer derived from trifluorostyrene on to at least one base polymer in a organic solvent/water mixture. These ion exchange polymers are useful in preparing catalyst coated membranes and membrane electrode assemblies used in fuel cells.

  6. Langevin-Poisson-EQT: A dipolar solvent based quasi-continuum approach for electric double layers

    Science.gov (United States)

    Mashayak, S. Y.; Aluru, N. R.

    2017-01-01

    Water is a highly polar solvent. As a result, electrostatic interactions of interfacial water molecules play a dominant role in determining the distribution of ions in electric double layers (EDLs). Near a surface, an inhomogeneous and anisotropic arrangement of water molecules gives rise to pronounced variations in the electrostatic and hydration energies of ions. Therefore, a detailed description of the structural and dielectric properties of water is important to study EDLs. However, most theoretical models ignore the molecular effects of water and treat water as a background continuum with a uniform dielectric permittivity. Explicit consideration of water polarization and hydration of ions is both theoretically and numerically challenging. In this work, we present an empirical potential-based quasi-continuum theory (EQT) for EDL, which incorporates the polarization and hydration effects of water explicitly. In EQT, water molecules are modeled as Langevin point dipoles and a point dipole based coarse-grained model for water is developed systematically. The space dependence of the dielectric permittivity of water is included in the Poisson equation to compute the electrostatic potential. In addition, to reproduce hydration of ions, ion-water coarse-grained potentials are developed. We demonstrate the EQT framework for EDL by simulating NaCl aqueous electrolyte confined inside slit-like capacitor channels at various ion concentrations and surface charge densities. We show that the ion and water density predictions from EQT agree well with the reference molecular dynamics simulations.

  7. Synthesis and thermo-physical properties of deep eutectic solvent-based graphene nanofluids.

    Science.gov (United States)

    Fang, Y K; Osama, M; Rashmi, W; Shahbaz, K; Khalid, M; Mjalli, F S; Farid, M M

    2016-02-19

    This study introduces a new class of heat transfer fluids by dispersing functionalised graphene oxide nanoparticles (GNPs) in ammonium and phosphonium-based deep eutectic solvents (DESs) without the aid of a surfactant. Different molar ratios of salts and hydrogen bond donors (HBD) were used to synthesise DESs for the preparation of different concentrations of graphene nanofluids (GNFs). The concentrations of GNPs were 0.01 wt%, 0.02 wt% and 0.05 wt %. Homogeneous and stable suspensions of nanofluids were obtained by high speed homogenisation and an ultrasonication process. The stability of the GNFs was determined through visual observation for 4 weeks followed by a centrifugal process (5000-20,000 rpm) for 30 min in addition to zeta potential studies. Dispersion of the GNPs in DES was observed using an optical microscope. The synthesised DES-based GNFs showed no particle agglomeration and formation of sediments in the nanofluids. Thermo-physical properties such as thermal conductivity and specific heat of the nanofluids were also investigated in this research. The highest thermal conductivity enhancement of 177% was observed. The findings of this research provide a new class of engineered fluid for heat transfer applications as a function of temperature, type and composition DESs as well as the GNPs concentration.

  8. Synthesis and thermo-physical properties of deep eutectic solvent-based graphene nanofluids

    Science.gov (United States)

    Fang, Y. K.; Osama, M.; Rashmi, W.; Shahbaz, K.; Khalid, M.; Mjalli, F. S.; Farid, M. M.

    2016-02-01

    This study introduces a new class of heat transfer fluids by dispersing functionalised graphene oxide nanoparticles (GNPs) in ammonium and phosphonium-based deep eutectic solvents (DESs) without the aid of a surfactant. Different molar ratios of salts and hydrogen bond donors (HBD) were used to synthesise DESs for the preparation of different concentrations of graphene nanofluids (GNFs). The concentrations of GNPs were 0.01 wt%, 0.02 wt% and 0.05 wt %. Homogeneous and stable suspensions of nanofluids were obtained by high speed homogenisation and an ultrasonication process. The stability of the GNFs was determined through visual observation for 4 weeks followed by a centrifugal process (5000-20 000 rpm) for 30 min in addition to zeta potential studies. Dispersion of the GNPs in DES was observed using an optical microscope. The synthesised DES-based GNFs showed no particle agglomeration and formation of sediments in the nanofluids. Thermo-physical properties such as thermal conductivity and specific heat of the nanofluids were also investigated in this research. The highest thermal conductivity enhancement of 177% was observed. The findings of this research provide a new class of engineered fluid for heat transfer applications as a function of temperature, type and composition DESs as well as the GNPs concentration.

  9. Synthesis and Structural Characterization of Magnesium Based Coordination Networks in Different Solvents

    Energy Technology Data Exchange (ETDEWEB)

    D Banerjee; J Finkelstein; A Smirnov; P Forster; L Borkowski; S Teat; J Parise

    2011-12-31

    Three magnesium based metal-organic frameworks, Mg{sub 3}(3,5-PDC){sub 3}(DMF){sub 3} {center_dot} DMF [1], Mg(3,5-PDC)(H{sub 2}O) {center_dot} (H{sub 2}O) [3], and Mg{sub 4}(3,5-PDC){sub 4}(DMF){sub 2}(H{sub 2}O){sub 2} {center_dot} 2DMF {center_dot} 4.5H{sub 2}O [4], and a 2-D coordination polymer, [Mg(3,5-PDC)(H{sub 2}O){sub 2}] [2] [PDC = pyridinedicarboxylate], were synthesized using a combination of DMF, methanol, ethanol, and water. Compound 1 [space group P2{sub 1}/n, a = 12.3475(5) {angstrom}, b = 11.1929(5) {angstrom}, c = 28.6734(12) {angstrom}, {beta} = 98.8160(10){sup o}, V = 3916.0(3) {angstrom}{sup 3}] consists of a combination of isolated and corner-sharing magnesium octahedra connected by the organic linkers to form a 3-D network with a 12.2 {angstrom} x 4.6 {angstrom} 1-D channel. The channel contains coordinated and free DMF molecules. In compound 2 [space group C2/c, a = 9.964(5) {angstrom}, b = 12.0694(6) {angstrom}, c = 7.2763(4) {angstrom}, {beta} = 106.4970(6){sup o}, V = 836.70(6) {angstrom}{sup 3}], PDC connects isolated seven coordinated magnesium polyhedra into a layered structure. Compound 3 [space group P6{sub 1}22, a = 11.479(1) {angstrom}, c = 14.735(3) {angstrom}, V = 1681.7(4) {angstrom}{sup 3}] (previously reported) contains isolated magnesium octahedra connected by the organic linker with each other forming a 3D network. Compound 4 [space group P2{sub 1}/c, a = 13.7442(14) {angstrom}, b = 14.2887(15) {angstrom}, c = 14.1178(14) {angstrom}, {beta} = 104.912(2){sup o}, V = 2679.2(5) {angstrom}{sup 3}] also exhibits a 3D network based on isolated magnesium octahedra with square cavities containing both disordered DMF and water molecules. The structural topologies originate due to the variable coordination ability of solvent molecules with the metal center. Water molecules coordinate with the magnesium metal centers preferably over other polar solvents (DMF, methanol, ethanol) used to synthesize the coordination networks. Despite

  10. Synthesis and Structural Characterization of Magnesium Based Coordination Networks in Different Solvents

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Debasis; Finkelstein, Jeffrey; Smirnov, A.; Forster, Paul M.; Borkowski, Lauren A.; Teat, Simon J.; Parise, John B. (LBNL); (UNLV); (Buffalo)

    2015-10-15

    Three magnesium based metal-organic frameworks, Mg{sub 3}(3,5-PDC){sub 3}(DMF){sub 3} {center_dot} DMF [1], Mg(3,5-PDC)(H{sub 2}O) {center_dot} (H{sub 2}O) [3], and Mg4(3,5-PDC)4(DMF){sub 2}(H{sub 2}O){sub 2} {center_dot} 2DMF {center_dot} 4.5H{sub 2}O [4], and a 2-D coordination polymer, [Mg(3,5-PDC)(H{sub 2}O){sub 2}] [2] [PDC = pyridinedicarboxylate], were synthesized using a combination of DMF, methanol, ethanol, and water. Compound 1 [space group P2{sub 1}/n, a = 12.3475(5) {angstrom}, b = 11.1929(5) {angstrom}, c = 28.6734(12) {angstrom}, {beta} = 98.8160(10){sup o}, V = 3916.0(3) {angstrom}{sup 3}] consists of a combination of isolated and corner-sharing magnesium octahedra connected by the organic linkers to form a 3-D network with a 12.2 {angstrom} x 4.6 {angstrom} 1-D channel. The channel contains coordinated and free DMF molecules. In compound 2 [space group C2/c, a = 9.964(5) {angstrom}, b = 12.0694(6) {angstrom}, c = 7.2763(4) {angstrom}, {beta} = 106.4970(6){sup o}, V = 836.70(6) {angstrom}{sup 3}], PDC connects isolated seven coordinated magnesium polyhedra into a layered structure. Compound 3 [space group P6{sub 1}22, a = 11.479(1) {angstrom}, c = 14.735(3) {angstrom}, V = 1681.7(4) {angstrom}{sup 3}] (previously reported) contains isolated magnesium octahedra connected by the organic linker with each other forming a 3D network. Compound 4 [space group P2{sub 1}/c, a = 13.7442(14) {angstrom}, b = 14.2887(15) {angstrom}, c = 14.1178(14) {angstrom}, {beta} = 104.912(2){sup o}, V = 2679.2(5) {angstrom}{sup 3}] also exhibits a 3D network based on isolated magnesium octahedra with square cavities containing both disordered DMF and water molecules. The structural topologies originate due to the variable coordination ability of solvent molecules with the metal center. Water molecules coordinate with the magnesium metal centers preferably over other polar solvents (DMF, methanol, ethanol) used to synthesize the coordination networks. Despite testing

  11. A novel 9 × 9 map-based solvent selection strategy for targeted counter-current chromatography isolation of natural products.

    Science.gov (United States)

    Liang, Junling; Meng, Jie; Wu, Dingfang; Guo, Mengzhe; Wu, Shihua

    2015-06-26

    Counter-current chromatography (CCC) is an efficient liquid-liquid chromatography technique for separation and purification of complex mixtures like natural products extracts and synthetic chemicals. However, CCC is still a challenging process requiring some special technical knowledge especially in the selection of appropriated solvent systems. In this work, we introduced a new 9 × 9 map-based solvent selection strategy for CCC isolation of targets, which permit more than 60 hexane-ethyl acetate-methanol-water (HEMWat) solvent systems as the start candidates for the selection of solvent systems. Among these solvent systems, there are clear linear correlations between partition coefficient (K) and the system numbers. Thus, an appropriate CCC solvent system (i.e., sweet spot for K = 1) may be hit by measurement of k values of the target only in two random solvent systems. Besides this, surprisingly, we found that through two sweet spots, we could get a line ("Sweet line") where there are infinite sweet solvent systems being suitable for CCC separation. In these sweet solvent systems, the target has the same partition coefficient (K) but different solubilities. Thus, the better sweet solvent system with higher sample solubility can be obtained for high capacity CCC preparation. Furthermore, we found that there is a zone ("Sweet zone") where all solvent systems have their own sweet partition coefficients values for the target in range of 0.4 natural products as standards and further confirmed by isolation of several targets including honokiol and magnolol from the extracts of Magnolia officinalis Rehd. Et Wils and tanshinone IIA from Salvia miltiorrhiza Bunge. In practice, it is much easier to get a suitable solvent system only by making a simple screening two to four HEMWat two-phase solvent systems to obtain the sweet line or sweet zone without special knowledge or comprehensive standards as references. This is an important advancement for solvent system selection

  12. Bio-based solvents: an emerging generation of fluids for the design of eco-efficient processes in catalysis and organic chemistry.

    Science.gov (United States)

    Gu, Yanlong; Jérôme, François

    2013-12-21

    Biomass and waste exhibit great potential for replacing fossil resources in the production of chemicals. The search for alternative reaction media to replace petroleum-based solvents commonly used in chemical processes is an important objective of significant environmental consequence. Recently, bio-based derivatives have been either used entirely as green solvents or utilized as pivotal ingredients for the production of innovative solvents potentially less toxic and more bio-compatible. This review presents the background and classification of these new media and highlights recent advances in their use in various areas including organic synthesis, catalysis, biotransformation and separation. The greenness, advantages and limitations of these solvents are also discussed.

  13. Choline chloride-based deep eutectic solvents as additives for optimizing chromatographic behavior of caffeic acid

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guizhen; Zhu, Tao; Lei, Yingjie [Tianjin University of Technology, Tianjin (China)

    2015-10-15

    A series of deep eutectic solvents (DESs) were prepared using glycerol and choline chloride (ChCl), and Fourier transform infrared spectrometer (FT-IR) was used to analyze the spectra of glycerol, choline chloride and DESs based on glycerol and choline chloride. Then DESs were used as the additives of mobile phase to optimize chromatographic behavior of caffeic acid in high performance liquid chromatography (HPLC). A 17-run Box-Behnken design (BBD) was employed to evaluate effect of DESs as additives by analyzing the maximum theoretical plate number. Three factors, reaction temperature (60 .deg. C, 80 .deg. C, 100 .deg. C), molar ratio of glycerol and choline chloride (2 : 1, 3 : 1, 4 : 1, n/n), and volume percent of additives (0.05%, 0.10%, 0.15%, v/v), were investigated in BBD. The optimum experiment condition was that of reaction temperature (80 .deg. C), molar ratio of glycerol and ChCl (3 : 1, n/n), and volume percent of additive (0.10%, v/v). The mean chromatographic theoretical plate number of the caffeic acid this condition was 1567.5, and DESs as additives shorten the retention time and modify the chromatogram shape, proving DESs as additives for effective theoretical plate number and column efficiency in HPLC.

  14. LSER-based modeling vapor pressures of (solvent+salt) systems by application of Xiang-Tan equation

    Institute of Scientific and Technical Information of China (English)

    Aynur Senol

    2015-01-01

    The study deals with modeling the vapor pressures of (solvent+salt) systems depending on the linear solvation energy relation (LSER) principles. The LSER-based vapor pressure model clarifies the simultaneous impact of the vapor pressure of a pure solvent estimated by the Xiang-Tan equation, the solubility and solvatochromic parameters of the solvent and the physical properties of the ionic salt. It has been performed independently two structural forms of the generalized solvation model, i.e. the unified solvation model with the integrated properties (USMIP) containing nine physical descriptors and the reduced property-basis solvation model. The vapor pressure data of fourteen (solvent+salt) systems have been processed to analyze statistical y the reliabil-ity of existing models in terms of a log-ratio objective function. The proposed vapor pressure approaches reproduce the observed performance relatively accurately, yielding the overall design factors of 1.0643 and 1.0702 for the integrated property-basis and reduced property-basis solvation models.

  15. Solvent-based dissolution method to sample gas-phase volatile organic compounds for compound-specific isotope analysis.

    Science.gov (United States)

    Bouchard, Daniel; Hunkeler, Daniel

    2014-01-17

    An investigation was carried out to develop a simple and efficient method to collect vapour samples for compound specific isotope analysis (CSIA) by bubbling vapours through an organic solvent (methanol or ethanol). The compounds tested were benzene and trichloroethylene (TCE). The dissolution efficiency was tested for different air volume injections, using flow rates ranging from 25ml/min to 150ml/min and injection periods varying between 10 and 40min. Based on the results, complete mass recovery for benzene and TCE in both solvents was observed for the flow rates of 25 and 50ml/min. However, small mass loss was observed at increased flow rate. At 150ml/min, recovery was on average 80±17% for benzene and 84±10% for TCE, respectively in methanol and ethanol. The δ(13)C data measured for benzene and TCE dissolved in both solvents were reproducible and were stable independently of the volume of air injected (up to 6L) or the flow rate used. The stability of δ(13)C values hence underlines no isotopic fractionation due to compound-solvent interaction or mass loss. The development of a novel and simple field sampling technique undertaken in this study will facilitate the application of CSIA to diverse gas-phase volatile organic compound studies, such as atmospheric emissions, soil gas or vapour intrusion.

  16. Deep Eutectic Solvent-Based Microwave-Assisted Method for Extraction of Hydrophilic and Hydrophobic Components from Radix Salviae miltiorrhizae

    Directory of Open Access Journals (Sweden)

    Jue Chen

    2016-10-01

    Full Text Available Deep eutectic solvents (DESs have attracted significant attention as a promising green media. In this work, twenty-five kinds of benign choline chloride-based DESs with microwave-assisted methods were applied to quickly extract active components from Radix Salviae miltiorrhizae. The extraction factors, including temperature, time, power of microwave, and solid/liquid ratio, were investigated systematically by response surface methodology. The hydrophilic and hydrophobic ingredients were extracted simultaneously under the optimized conditions: 20 vol% of water in choline chloride/1,2-propanediol (1:1, molar ratio as solvent, microwave power of 800 W, temperature at 70 °C, time at 11.11 min, and solid/liquid ratio of 0.007 g·mL−1. The extraction yield was comparable to, or even better than, conventional methods with organic solvents. The microstructure alteration of samples before and after extraction was also investigated. The method validation was tested as the linearity of analytes (r2 > 0.9997 over two orders of magnitude, precision (intra-day relative standard deviation (RSD < 2.49 and inter-day RSD < 2.96, and accuracy (recoveries ranging from 95.04% to 99.93%. The proposed DESs combined with the microwave-assisted method provided a prominent advantage for fast and efficient extraction of active components, and DESs could be extended as solvents to extract and analyze complex environmental and pharmaceutical samples.

  17. Influence of the type of solvent on the development of superhydrophobicity from silane-based solution containing nanoparticles

    Science.gov (United States)

    Pantoja, M.; Abenojar, J.; Martinez, M. A.

    2017-03-01

    Superhydrophobic surfaces are very appealing for numerous industrial applications due to their self-cleaning capacity. Although there are different methods to manufacture superhydrophobic surfaces, some of them do not keep the aesthetic appearance of the neat surface. Sol-gel processes are a valid alternative when transparent coatings are desired. The main goal of this research is to study the viability of this method by making superhydrophobic coatings from silane-based solution containing SiO2 nanoparticles. The effect of using different solvents is investigated, as well as the role played by the different components of the solution (silane, nanoparticles and solvent). Solutions of methyltrimethoxisilane (MTS) and tetraethoxysilane (TEOS) and 1% of SiO2 (%wt) were prepared with different solvents (ethanol, ethanol/water and white spirit). The hydrophobicity of the developed coatings is studied using contact angle measurements, while the aesthetic appearance is evaluated with gloss and color measurements. Also, infrared spectroscopy, dynamic light scattering (DSL), and surface tension measurements are used to study the silane solutions. The results show that the capacity of solvents to promote the dispersion of the nanoparticles is crucial to ensuring superhydrophobicity, since these agglomerates provide the micro- and nano- surface roughness required to get a hierarchical structure. However, the combined use of silanes and nanoparticles is key to make a superhydrophobic surface because physical (the surface roughness provided by nanoparticles) and chemical characteristics (hydrophobicity provided by silanes) are coupled.

  18. Solvent Debinding of MIM Parts in a Polystyrene-Palm Oil Based Binder System

    Science.gov (United States)

    Asmawi, R.; Ibrahim, M. H. I.; Amin, A. M.; Mustafa, N.

    2016-11-01

    The influence of the leaching temperatures on the solvent debinding process of SS316L stainless steel alloy compact has been investigated. Solvent debinding process of injection moulded SS316L feedstock was conducted to eliminate palm kernel oil by using n- heptane solution at various temperatures of 40, 50 and 60°C and at different time duration up to 9 hours. The samples were prepared by injection molding a mixture of stainless steel SS316L alloy with waste polystyrene polymer and palm kernel oil at powder loading 60% vol. The weight loss percentages of palm kernel were calculated and the pore structure evolution was analyzed by scanning electron micrograph to observe the pores created after solvent extraction process. Results show that a complete diffusion of the palm kernel molecules out of the compact part best at 60°C within 6 hours of extraction time

  19. In Vitro and In Vivo toxicity profiling of ammonium-based deep eutectic solvents.

    Directory of Open Access Journals (Sweden)

    Maan Hayyan

    Full Text Available The cytotoxic potential of ammonium-based deep eutectic solvents (DESs with four hydrogen bond donors, namely glycerine (Gl, ethylene glycol (EG, triethylene glycol (TEG and urea (U were investigated. The toxicity of DESs was examined using In Vitro cell lines and In Vivo animal model. IC50 and selectivity index were determined for the DESs, their individual components and their combinations as aqueous solutions for comparison purposes. The cytotoxicity effect of DESs varied depending on cell lines. The IC50 for the GlDES, EGDES, UDES and TEGDES followed the sequence of TEGDES< GlDES< EGDES< UDES for OKF6, MCF-7, A375, HT29 and H413, respectively. GlDES was selective against MCF-7 and A375, EGDES was selective against MCF-7, PC3, HepG2 and HT29, UDES was selective against MCF-7, PC3, HepG2 and HT29, and TEGDES was selective against MCF-7 and A375. However, acute toxicity studies using ICR mice showed that these DESs were relatively toxic in comparison to their individual components. DES did not cause DNA damage, but it could enhance ROS production and induce apoptosis in treated cancer cells as evidenced by marked LDH release. Furthermore, the examined DESs showed less cytotoxicity compared with ionic liquids. To the best of our knowledge, this is the first time that combined In Vitro and In Vivo toxicity profiles of DESs were being demonstrated, raising the toxicity issue of these neoteric mixtures and their potential applicability to be used for therapeutic purposes.

  20. The potential applications in heavy oil EOR with the nanoparticle and surfactant stabilized solvent-based emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, F. [Texas A and M Univ., College Station, TX (United States)

    2010-07-01

    The main challenges in developing the heavy oil reservoirs in the Alaska North Slope (ANS) include technical challenges regarding thermal recovery; sand control and disposal; high asphaltene content; and low in-situ permeability. A chemical enhanced oil recovery method may be possible for these reservoirs. Solvent based emulsion flooding provides mobility control; oil viscosity reduction; and in-situ emulsification of heavy oil. This study evaluated the potential application of nano-particle-stabilized solvent based emulsion injection to enhance heavy oil recovery in the ANS. The optimized micro-emulsion composition was determined using laboratory tests such as phase behaviour scanning, rheology studies and interfacial tension measurements. The optimized nano-emulsions were used in core flooding experiments to verify the recovery efficiency. The study revealed that the potential use of this kind of emulsion flooding is a promising enhanced oil recovery process for some heavy oil reservoirs in Alaska, Canada and Venezuela. 4 refs., 2 tabs., 10 figs.

  1. Solvent substitution

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

  2. Evaluation of solvent system for the enzymatic synthesis of ethanol-based biodiesel from sludge palm oil (SPO).

    Science.gov (United States)

    Nasaruddin, Ricca Rahman; Alam, Md Zahangir; Jami, Mohammed Saedi

    2014-02-01

    A green technology of biodiesel production focuses on the use of enzymes as the catalyst. In enzymatic biodiesel synthesis, suitable solvent system is very essential to reduce the inhibition effects of the solvent to the enzymes. This study produced ethanol-based biodiesel from a low-cost sludge palm oil (SPO) using locally-produced Candida cylindracea lipase from fermentation of palm oil mill effluent (POME) based medium. The optimum levels of ethanol-to-SPO molar ratio and enzyme loading were found to be 4:1 and 10 U/25 g of SPO respectively with 54.4% w/w SPO yield of biodiesel and 21.7% conversion of free fatty acid (FFA) into biodiesel. Addition of tert-butanol at 2:1 tert-butanol-to-SPO molar ratio into the ethanol-solvent system increased the yield of biodiesel to 71.6% w/w SPO and conversion of FFA into biodiesel to 28.8%. The SPO and ethanol have promising potential for the production of renewable biodiesel using enzymatic-catalyzed esterification and transesterification.

  3. Novel shortcut estimation method for regeneration energy of amine solvents in an absorption-based carbon capture process.

    Science.gov (United States)

    Kim, Huiyong; Hwang, Sung June; Lee, Kwang Soon

    2015-02-03

    Among various CO2 capture processes, the aqueous amine-based absorption process is considered the most promising for near-term deployment. However, the performance evaluation of newly developed solvents still requires complex and time-consuming procedures, such as pilot plant tests or the development of a rigorous simulator. Absence of accurate and simple calculation methods for the energy performance at an early stage of process development has lengthened and increased expense of the development of economically feasible CO2 capture processes. In this paper, a novel but simple method to reliably calculate the regeneration energy in a standard amine-based carbon capture process is proposed. Careful examination of stripper behaviors and exploitation of energy balance equations around the stripper allowed for calculation of the regeneration energy using only vapor-liquid equilibrium and caloric data. Reliability of the proposed method was confirmed by comparing to rigorous simulations for two well-known solvents, monoethanolamine (MEA) and piperazine (PZ). The proposed method can predict the regeneration energy at various operating conditions with greater simplicity, greater speed, and higher accuracy than those proposed in previous studies. This enables faster and more precise screening of various solvents and faster optimization of process variables and can eventually accelerate the development of economically deployable CO2 capture processes.

  4. Solvent exposure and malignant lymphoma: a population-based case-control study in Germany

    Directory of Open Access Journals (Sweden)

    Deeg Evelin

    2007-04-01

    Full Text Available Abstract Aims To analyze the relationship between exposure to chlorinated and aromatic organic solvents and malignant lymphoma in a multi-centre, population-based case-control study. Methods Male and female patients with malignant lymphoma (n = 710 between 18 and 80 years of age were prospectively recruited in six study regions in Germany (Ludwigshafen/Upper Palatinate, Heidelberg/Rhine-Neckar-County, Würzburg/Lower Frankonia, Hamburg, Bielefeld/Gütersloh, and Munich. For each newly recruited lymphoma case, a gender, region and age-matched (± 1 year of birth population control was drawn from the population registers. In a structured personal interview, we elicited a complete occupational history, including every occupational period that lasted at least one year. On the basis of job task-specific supplementary questionnaires, a trained occupational physician assessed the exposure to chlorinated hydrocarbons (trichloroethylene, tetrachloroethylene, dichloromethane, carbon tetrachloride and aromatic hydrocarbons (benzene, toluene, xylene, styrene. Odds ratios (OR and 95% confidence intervals (CI were calculated using conditional logistic regression analysis, adjusted for smoking (in pack years and alcohol consumption. To increase the statistical power, patients with specific lymphoma subentities were additionally compared with the entire control group using unconditional logistic regression analysis. Results We observed a statistically significant association between high exposure to chlorinated hydrocarbons and malignant lymphoma (Odds ratio = 2.1; 95% confidence interval 1.1–4.3. In the analysis of lymphoma subentities, a pronounced risk elevation was found for follicular lymphoma and marginal zone lymphoma. When specific substances were considered, the association between trichloroethylene and malignant lymphoma was of borderline statistical significance. Aromatic hydrocarbons were not significantly associated with the lymphoma diagnosis

  5. Solvent-free melting techniques for the preparation of lipid-based solid oral formulations.

    Science.gov (United States)

    Becker, Karin; Salar-Behzadi, Sharareh; Zimmer, Andreas

    2015-05-01

    Lipid excipients are applied for numerous purposes such as taste masking, controlled release, improvement of swallowability and moisture protection. Several melting techniques have evolved in the last decades. Common examples are melt coating, melt granulation and melt extrusion. The required equipment ranges from ordinary glass beakers for lab scale up to large machines such as fluid bed coaters, spray dryers or extruders. This allows for upscaling to pilot or production scale. Solvent free melt processing provides a cost-effective, time-saving and eco-friendly method for the food and pharmaceutical industries. This review intends to give a critical overview of the published literature on experiences, formulations and challenges and to show possibilities for future developments in this promising field. Moreover, it should serve as a guide for selecting the best excipients and manufacturing techniques for the development of a product with specific properties using solvent free melt processing.

  6. An efficient phase-selective gelator for aromatic solvents recovery based on a cyanostilbene amide derivative.

    Science.gov (United States)

    Zhang, Yuping; Ma, Yao; Deng, Mengyu; Shang, Hongxing; Liang, Chunshuang; Jiang, Shimei

    2015-07-07

    Two novel low molecular weight organogelators (LMOGs) 1 and 2 composed of a cholesteryl group, an amide group and various terminal cyanostilbene moieties were synthesized. They could form stable gels in p-xylene. In particular, 2 with more extended π-conjugation length showed remarkable gelation ability in many aromatic solvents, chloroform and chloroform-containing mixed solvents at a relatively low concentration. FT-IR and XRD spectra indicated that the difference between 1 and 2 in the gelation properties may result from the deviation of the intermolecular hydrogen bonding and π–π stacking as driving forces for the formation of the gels. Significantly, 2 can function as an efficient room-temperature phase-selective gelator (PSG) for potential application in the separation and recovery of various aromatic solvents from its mixture with water. Meanwhile, the gelator can be easily recovered and reused several times. Furthermore, the phase-selective gelation properties of 2 can provide a simple and feasible approach for the removal of the rhodamine B (RhB) dye from water.

  7. DFT-based simulations of amide I' IR spectra of a small protein in solution using empirical electrostatic map with a continuum solvent model.

    Science.gov (United States)

    Welch, William R W; Kubelka, Jan

    2012-09-01

    A continuum solvent model was tested for simulations of amide I' IR spectra for a 40-residue subdomain of P22 viral coat protein in aqueous solution. Spectra obtained using DFT (BPW91/6-31G**) parameters for a reduced all-Ala representation of the protein were corrected by an electrostatic potential map obtained from the solvent cavity surface and AMBER99 side-chain atom partial charges. Various cavity sizes derived from van der Waals atomic radii with an added effective solvent radius up to 2.0 Å were tested. The interplay of the side-chain and solvent electrostatic effects was investigated by considering the side chains and solvent separately as well as together. The sensitivity to side-chain conformational fluctuations and to the parametrization of C(β) group partial charges was also tested. Simulation results were compared to the experimental amide I' spectra of P22 subdomain, including two (13)C isotopically edited variants, as well as to the previous simulations based on the molecular dynamics trajectory in explicit solvent. For small cavity sizes, between van der Waals and that with added solvent radius of 0.5 Å, better qualitative agreement with experiment was obtained than with the explicit solvent representation, in particular for the (13)C-labeled spectra. Larger protein cavities led to progressively worse predictions due to increasingly stronger electrostatic effects of side chains, which could no longer be well compensated for by the solvent potential. Balance between side-chain and solvent electrostatic effects is important in determining the width and shape of the simulated amide I', which is also virtually unaffected by side-chain-geometry fluctuations. The continuum solvent model combined with the electrostatic map is a computationally efficient and potentially robust approach for the simulations of IR spectra of proteins in solution.

  8. Effect of organic solvents on peroxidases from rice and horseradish: prospects for enzyme based applications.

    Science.gov (United States)

    Singh, Priyanka; Prakash, Rajiv; Shah, Kavita

    2012-08-15

    A feasibility test for rice peroxidase (RP) enzyme as a substitute for horseradish peroxidase (HRP) was carried out. The activity of HRP was maximum at 30 °C with pH 6.0-7.0. The purified rice peroxidase showed optimum activity at 30 °C with pH 7-8 and was thermostable till 68 °C, which is higher than the temperature reported for HRP. RP obeyed Michaelis-Menten kinetics. With increasing substrate concentrations, RP and HRP had V(max) as 8.23 μM min(-1) and 4.21 μM min(-1) and K(m) as 5.585 and 3.662 mM, respectively. In 10% 1,4-dioxane and ethanol, RP exhibited 2 and 1.3 times higher activity, respectively than HRP. Shelf life studies show RP to be significantly stable till 60 h in 20% 1,4-dioxane and till 12 h in ethanol. The activity of RP/HRP increased gradually with 0%-40% ethanol or 0%-30% 1,4-dioxane till 20 h with a sharp decline thereafter. The stability of HRP and RP reduced with increasing storage period. Enzyme efficiencies compared as V(m)/K(m) showed water miscible organic solvents, viz.1,4-dioxane and ethanol, to exhibit a regular decrease in V(m)/K(m) with increase in organic solvent concentration whereas, a reverse trend was observed with water-immiscible solvent like chloroform. The relative activity of RP and HRP enzymes upon immobilization on poly-5-carboxy-indole shows increasing enzyme activity with time and with guaiacol/dopamine hydrochloride as substrates. Immobilized RP had a better relative activity with dopamine as substrate than immobilized HRP, whereas with guaiacol both RP and HRP had a comparable activity upon immobilization. Results suggest rice peroxidase to be a cheaper and convenient enzyme system for immobilization using organic solvents. The high thermal stability, more stability in organic solvents and longer shelf life of RP over the immobilizing matrix suggest conducting polyindole having carboxyl functional groups to be a suitable matrix for the covalent entrapment of rice peroxidase through amide linkage. Good

  9. Direct and ultrasensitive optofluidic-based immunosensing assay of aflatoxin M1 in dairy products using organic solvent extraction.

    Science.gov (United States)

    Lou, Xuening; Zhu, Anna; Wang, Hongliang; Wu, Jun; Zhou, Liping; Long, Feng

    2016-10-12

    Aflatoxin M1 (AFM1), a highly toxic secondary metabolite, is present in a wide range of dairy products. In this study, we designed a simple, low-cost, reusable, and easy-to-operate immunosensing method for ultrasensitive detection of AFM1 in dairy products by using a portable evanescent wave-based optofluidic biosensing platform (EOBP). The developed method provides the minimum detection limit of 5 ng/L, which is below the most restrictive standard imposed by the current regulations for AFM1 in dairy products. The effect of several organic solvents, such as methanol, acetone, and acetonitrile, on the binding reaction of antibody-antigen in heterogeneous and homogeneous solutions was evaluated. Although the effect of organic solvents on the homogeneous binding reaction between antibody and antigen is more significant than that of heterogeneous binding reaction between antibody in solution and antigen immobilized onto the sensor surface, the fluorescence signal detected by EOBP is linearly dependent on AFM1 concentration. Therefore, AFM1 can be directly quantified even if the samples contain a certain organic solvent concentration. The robustness and stability of AFM1-ovalbumin conjugate allow the regeneration of modified biosensor surface for more than 200 times, thereby achieving a cost-effective and reliable AFM1 determination. The proposed method provides a rapid, ultrasensitive, and reliable AFM1 determination in dairy products without complicated sample pretreatment process.

  10. Impact of solvents and supercritical CO{sub 2} drying on the morphology and structure of polymer-based biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Causa, Andrea; Acierno, Domenico; Filippone, Giovanni [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli Federico II, Piazzale V. Tecchio, 80, 80125 Napoli (Italy); Salerno, Aurelio; Domingo, Concepción [Instituto de Ciencia de Materiales de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra (Spain)

    2014-05-15

    In the present work, two-dimensional systems based on biodegradable polymers such as poly(ε-caprolactone) (PCL), poly(ethylene oxide) (PEO) and polylactic acid (PLA) are fabricated by means of a sustainable approach which consists in inducing phase separation in solutions of such polymers and “green” solvents, namely ethyl lactate (EL) and ethyl acetate (EA). The extraction of the solvent is promoted by a controlled drying process, which is performed in either air or supercritical CO{sub 2}. The latter can indeed act as both an antisolvent, which favors the deposition of the polymer by forming a mixture with EL and EA, and a plasticizing agent, whose solvation and transport properties may considerably affect the microstructure and crystallinity of the polymer films. The morphological, topographical and crystalline properties of the films are tailored through a judicial selection of the materials and the processing conditions and assessed by means of thermal analyses, polarized optical microscopy, scanning electron microscopy and confocal interferometric microscopy. The results show that the morphological and crystalline properties of the films are strongly dependent on the choice of both the polymer/solvent system and the operating conditions during the drying step. In particular, the morphological, topographical and thermal properties of films prepared starting from highly crystalline polymers, namely PCL and PEO, are greatly affected by the crystallization of the material. Conversely, the less crystalline PLA forms almost completely amorphous films.

  11. Experimental and DFT studies of solvent effects on molecular structure and physical properties of Dipyridylamine pyridine based ligand

    Science.gov (United States)

    Bilkan, Mustafa Tuğfan; Şahin, Onur; Yurdakul, Şenay

    2017-04-01

    The solvent effects on molecular structure, electronic, vibrational and thermochemical properties of 2,2‧-Dipyridylamine were investigated by using experimental and theoretical methods. 2,2‧-Dipyridylamine molecule was selected for this study intentionally because it has two pyridyl rings connected by amine bridge. This allows to change the stable equilibrium geometry, even the slightest effects. Dichloromethane was chosen as solvent. The reason for this selection is to examine whether the chlorine atoms make hydrogen bonds with the ligand atoms. For this purpose, firstly 2,2‧-Dipyridylamine solution was prepared and characterized by FT-IR and FT-Raman spectroscopy. Secondly, crystal structure of 2,2‧-Dipyridylamine was obtained to compare with the calculated geometric parameters. The crystal structure was analyzed by Single Crystal X-Ray diffraction methods. Density Functional Theory calculations were conducted with B3LYP functional and 6-31G(d) basis set. The theoretical vibrational properties of optimized geometric structure were computed in vapor and solvation phases. Two different theoretical approaches were discussed, based on the experimental results. It can be seen from the experimental and theoretical studies that the structural, vibrational, thermochemical and electronic properties are dependent on the solvent effects for selected structure. Furthermore, the chlorine atoms of Dichloromethane do not make hydrogen bonds with the ligand atoms.

  12. High-performance dye-sensitized solar cells based on solvent-free electrolytes produced from eutectic melts.

    Science.gov (United States)

    Bai, Yu; Cao, Yiming; Zhang, Jing; Wang, Mingkui; Li, Renzhi; Wang, Peng; Zakeeruddin, Shaik M; Grätzel, Michael

    2008-08-01

    Low-cost excitonic solar cells based on organic optoelectronic materials are receiving an ever-increasing amount of attention as potential alternatives to traditional inorganic photovoltaic devices. In this rapidly developing field, the dye-sensitized solar cell (DSC) has achieved so far the highest validated efficiency of 11.1% (ref. 2) and remarkable stability. However, the cells with the best performance use volatile solvents in their electrolytes, which may be prohibitive for outdoor solar panels in view of the need for robust encapsulation. Solvent-free room-temperature ionic liquids have been pursued as an attractive solution to this dilemma, and device efficiencies of over 7% were achieved by using some low-viscosity formulations containing 1-ethyl-3-methylimidazolium thiocyanate, selenocyanate, tricyanomethide or tetracyanoborate. Unfortunately, apart from tetracyanoborate, all of these low-viscosity melts proved to be unstable under prolonged thermal stress and light soaking. Here, we introduce the concept of using eutectic melts to produce solvent-free liquid redox electrolytes. Using a ternary melt in conjunction with a nanocrystalline titania film and the amphiphilic heteroleptic ruthenium complex Z907Na (ref. 10) as a sensitizer, we reach excellent stability and an unprecedented efficiency of 8.2% under air-mass 1.5 global illumination. Our results are of importance to realize large-scale outdoor applications of mesoscopic DSCs.

  13. Alternative bio-based solvents for extraction of fat and oils: solubility prediction, global yield, extraction kinetics, chemical composition and cost of manufacturing.

    Science.gov (United States)

    Sicaire, Anne-Gaëlle; Vian, Maryline; Fine, Frédéric; Joffre, Florent; Carré, Patrick; Tostain, Sylvain; Chemat, Farid

    2015-04-15

    The present study was designed to evaluate the performance of alternative bio-based solvents, more especially 2-methyltetrahydrofuran, obtained from crop's byproducts for the substitution of petroleum solvents such as hexane in the extraction of fat and oils for food (edible oil) and non-food (bio fuel) applications. First a solvent selection as well as an evaluation of the performance was made with Hansen Solubility Parameters and the COnductor-like Screening MOdel for Realistic Solvation (COSMO-RS) simulations. Experiments were performed on rapeseed oil extraction at laboratory and pilot plant scale for the determination of lipid yields, extraction kinetics, diffusion modeling, and complete lipid composition in term of fatty acids and micronutrients (sterols, tocopherols and tocotrienols). Finally, economic and energetic evaluations of the process were conducted to estimate the cost of manufacturing using 2-methyltetrahydrofuran (MeTHF) as alternative solvent compared to hexane as petroleum solvent.

  14. Alternative Bio-Based Solvents for Extraction of Fat and Oils: Solubility Prediction, Global Yield, Extraction Kinetics, Chemical Composition and Cost of Manufacturing

    Directory of Open Access Journals (Sweden)

    Anne-Gaëlle Sicaire

    2015-04-01

    Full Text Available The present study was designed to evaluate the performance of alternative bio-based solvents, more especially 2-methyltetrahydrofuran, obtained from crop’s byproducts for the substitution of petroleum solvents such as hexane in the extraction of fat and oils for food (edible oil and non-food (bio fuel applications. First a solvent selection as well as an evaluation of the performance was made with Hansen Solubility Parameters and the COnductor-like Screening MOdel for Realistic Solvation (COSMO-RS simulations. Experiments were performed on rapeseed oil extraction at laboratory and pilot plant scale for the determination of lipid yields, extraction kinetics, diffusion modeling, and complete lipid composition in term of fatty acids and micronutrients (sterols, tocopherols and tocotrienols. Finally, economic and energetic evaluations of the process were conducted to estimate the cost of manufacturing using 2-methyltetrahydrofuran (MeTHF as alternative solvent compared to hexane as petroleum solvent.

  15. A new decomposition-based computer-aided molecular/mixture design methodology for the design of optimal solvents and solvent mixtures

    DEFF Research Database (Denmark)

    Karunanithi, A.T.; Achenie, L.E.K.; Gani, Rafiqul

    2005-01-01

    This paper presents a novel computer-aided molecular/mixture design (CAMD) methodology for the design of optimal solvents and solvent mixtures. The molecular/mixture design problem is formulated as a mixed integer nonlinear programming (MINLP) model in which a performance objective...... is to be optimized subject to structural, property, and process constraints. The general molecular/mixture design problem is divided into two parts. For optimal single-compound design, the first part is solved. For mixture design, the single-compound design is first carried out to identify candidates...... the design of an optimal extractant for the separation of acetic acid from water by liquid-liquid extraction. The results suggest that the new extractant would be able to perform better than the extractant being widely used for this separation. The second case study is an industrial problem involving...

  16. Solvent-induced O-H vibration red-shifts of oxygen-acids in hydrogen-bonded O-H···base complexes.

    Science.gov (United States)

    Keinan, Sharon; Pines, Dina; Kiefer, Philip M; Hynes, James T; Pines, Ehud

    2015-01-22

    Infrared spectroscopy has been used to characterize the solvent effect on the OH stretching vibrations νOH of phenol, 1-naphthol, 2-naphthol, 1-hydroxypyrene, and ethanol. We distinguish the dielectric (nonspecific) effect of the solvent on ΔνOH, the observed red-shifts in νOH, from the much larger red-shift caused by direct hydrogen (H)-bonding interactions with the solvents. To isolate the solvent dielectric constant ε effect on νOH, the OH oscillator was also studied when it is already H-bonded with an invariant oxygen base, dimethyl sulfoxide. We find that ΔνOH depends importantly on ΔPA, the difference between the proton affinities of the conjugate base of the proton donor and the proton acceptor. For a given H-bonded complex, νOH tends to vary inversely with ε, exhibiting different slopes for polar and nonpolar solvents, i.e., solvents comprising molecules with and without a permanent dipole moment, respectively. We use a two-state valence-bond-based theory to analyze our experimental data. This demonstrates that the OH oscillator acquires a more ionic-like character in the vibrational excited state, i.e., charge transfer; this results in a stronger H-bond in a more anharmonic potential for the OH vibration. The theory distinguishes between nonpolar and polar solvents and successfully accounts for the observed 1/ε and ΔPA variations.

  17. Thermodynamically based solvent design for enzymatic saccharide acylation with hydroxycinnamic acids in non-conventional media

    DEFF Research Database (Denmark)

    Zeuner, Birgitte; Kontogeorgis, Georgios; Riisager, Anders

    2012-01-01

    Enzyme-catalyzed synthesis has been widely studied with lipases (EC 3.1.1.3), but feruloyl esterases (FAEs; EC 3.1.1.73) may provide advantages such as higher substrate affinity and regioselectivity in the synthesis of hydroxycinnamate saccharide esters. These compounds are interesting because...... of their amphiphilicity and antioxidative potential. Synthetic reactions using mono- or disaccharides as one of the substrates may moreover direct new routes for biomass upgrading in the biorefinery. The paper reviews the available data for enzymatic hydroxycinnamate saccharide ester synthesis in organic solvent systems...

  18. A Diazonium Salt-Based Ionic Liquid for Solvent-FreeModification of Carbon.

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chengdu [ORNL; Huang, Jing-Fang [ORNL; Li, Zuojiang [ORNL; Luo, Huimin [ORNL; Dai, Sheng [ORNL

    2006-01-01

    A novel ionic liquid that consists of p-butylbenzenediazonium ions and bis(trifluoromethanesulfonyl)amidates (Tf{sub 2}N{sup -}) has been synthesized as a task-specific ionic liquid for the solvent-free modification of carbon materials. The use of anions Tf{sub 2}N{sup =} is the key to rendering the hydrophobicity, low liquidus temperature, and ionicity to this novel molten salt. This diazonium salt has a melting point of 7.2 C and a moderate electric conductivity of 527 {micro} s/cm at 25 C. The thermal stability of this diazonium ionic liquid has been investigated by high-resolution thermogravimetric analysis (HRTGA). The compound is stable up to about 90 C in nitrogen, which is only 10 C less than its solid tetrafluoroborate counterpart. The modification of carbon materials has been carried out through both thermal and electrochemical activations of diazonium ions to generate free radical intermediates without the use of any solvent. The surface-coverage loadings of 3.38 {micro} mol/m{sup 2} and 6.07 {micro} mol/m{sup 2} for covalently attached organic functionalities have been achieved by the thermally induced functionalization and electrochemically assisted reaction, respectively.

  19. Thermodynamic constrains for life based on non-aqueous polar solvents on free-floating planets.

    Science.gov (United States)

    Badescu, Viorel

    2011-02-01

    Free-floating planets (FFPs) might originate either around a star or in solitary fashion. These bodies can retain molecular gases atmospheres which, upon cooling, have basal pressures of tens of bars or more. Pressure-induced opacity of these gases prevents such a body from eliminating its internal radioactive heat and its surface temperature can exceed for a long term the melting temperature of a life-supporting solvent. In this paper two non-aqueous but still polar solvents are considered: hydrogen sulfide and ammonia. Thermodynamic requirements to be fulfilled by a hypothetic gas constituent of a life-supporting FFP's atmosphere are studied. The three gases analyzed here (nitrogen, methane and ethane) are candidates. We show that bodies with ammonia oceans are possible in interstellar space. This may happen on FFPs of (significantly) smaller or larger mass than the Earth. Generally, in case of FFP smaller in size than the Earth, the atmosphere exhibits a convective layer near the surface and a radiative layer at higher altitudes while the atmosphere of FFPs larger in size than Earth does not exhibit a convective layer. The atmosphere mass of a life-hosting FFP of Earth size is two or three orders of magnitude larger than the mass of Earth atmosphere. For FFPs larger than the Earth and specific values of surface pressure and temperature, there are conditions for condensation (in the ethane atmosphere). Some arguments induce the conclusion than the associated surface pressures and temperatures should be treated with caution as appropriate life conditions.

  20. Mechanism of gold solvent extraction from aurocyanide solution by quaternary amines: models of extracting species based on hydrogen bonding

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The mechanism of gold solvent extraction from KAu(CN)2 solution was investigated by means of FTIR, EXAFS, ICP and radioactive tracer methods. Two extraction systems were studied, namely N263-tributyl phosphate(TBP)-n-dodecane and N263-iso-octanol-n-dodecane. High-reso- lution FT IR spectroscopy indicated that the CN stretching vibrations of the two extraction systems differred greatly. In order to interpret the significant difference in CN stretching vibrations, two extracting species models are proposed supramolecular structures based on the formation of hydrogen bonds between Au(CN)2- and modifiers such as TBP and iso-octanol.

  1. Mechanism of gold solvent extraction from aurocyanide solution by quaternary amines: models of extracting species based on hydrogen bonding

    Institute of Scientific and Technical Information of China (English)

    马刚; 闫文飞; 陈景; 严纯华; 高宏成; 周维金; 施鼐; 吴谨光; 徐光宪; 黄昆; 余建民; 崔宁

    2000-01-01

    The mechanism of gold solvent extraction from KAu(CN)2 solution was investigated by means of FTIR, EXAFS, ICP and radioactive tracer methods. Two extraction systems were studied, namely N263-tributyl phosphate(TBP)-n-dodecane and N263-iso-octanol-n-dodecane. High-resolution FT IR spectroscopy indicated that the CN stretching vibrations of the two extraction systems differred greatly. In order to interpret the significant difference in CN stretching vibrations, twoextracting species models are proposed——supramolecular structures based on the formation ofhydrogen bonds between Au(CN)2- and modifiers such as TBP and iso-octanol.

  2. Fast environment-friendly ball mill-assisted deep eutectic solvent-based extraction of natural products.

    Science.gov (United States)

    Wang, Man; Wang, Jiaqin; Zhang, Yue; Xia, Qian; Bi, Wentao; Yang, Xiaodi; Chen, David Da Yong

    2016-04-22

    A fast environment-friendly extraction method, ball mill-assisted deep eutectic solvent-based extraction, was used for the extraction of natural products from plants. In this study, tanshinones were selected as target compounds to evaluate the efficiency of the developed extraction method. Under the optimized experimental conditions, cryptotanshinone (0.176 mg/g), tanshinone I (0.181 mg/g), and tanshinone II A (0.421 mg/g) were extracted from Salvia miltiorrhiza Bunge, and the developed method was found to be greener, more efficient, and faster than conventional, environmentally harmful extraction methods such as methanol-based ultrasound-assisted extraction and heat reflux extraction. The analytical performances including recovery, reproducibility (RSD, n=5), correlation of determination (r(2)), and the limit of detection, with the ranges of 96.1-103.9%, 1.6-1.9%, 0.9973-0.9984, and 5-8 ng/mL, were respectively obtained. Application of ball mill-assisted deep eutectic solvent-based extraction may fundamentally shape the future development of extraction methods.

  3. Tetrabutylammonium Bromide (TBABr-Based Deep Eutectic Solvents (DESs and Their Physical Properties

    Directory of Open Access Journals (Sweden)

    Rizana Yusof

    2014-06-01

    Full Text Available Density, viscosity and ionic conductivity data sets of deep eutectic solvents (DESs formed by tetrabutylammonium bromide (TBABr paired with ethlyene glycol, 1,3-propanediol, 1,5-pentanediol and glycerol hydrogen bond donors (HBDs are reported. The properties of DES were measured at temperatures between 303 K and 333 K for HBD percentages of 66.7% to 90%. The effects of HBDs under different temperature and percentages are systematically analyzed. As expected, the measured density and viscosity of the studied DESs decreased with an increase in temperature, while ionic conductivity increases with temperature. In general, DESs made of TBABr and glycerol showed the highest density and viscosity and the lowest ionic conductivity when compared to other DESs. The presence of an extra hydroxyl group on glycerol in a DES affected the properties of the DES.

  4. The Effects of Solvent and Added Bases on the Protection of Benzylamines with Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Amy L. Ethier

    2015-06-01

    Full Text Available The introduction and removal of protecting groups is ubiquitous in multi-step synthetic schemes. From a green chemistry standpoint, however, alternative strategies that employ in situ and reversible protection and deprotection sequences would be attractive. The reversible reactions of CO2 with amines could provide a possible vehicle for realizing this strategy. Herein, we present (1 the products of reaction of benzylamines with CO2 in a variety of solvents with and without the presence of basic additives; (2 new adducts associated with CO2 protected benzylamine in acetonitrile containing 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU; and (3 the intermolecular competitive acylation of benzylamine and benzyl alcohol and the intramolecular competitive acylation of (4-aminomethylphenyl methanol with isopropenyl acetate in acetonitrile containing DBU in the absence and presence of CO2.

  5. Synthesis, Characterization and Printing Application of Solvent Dyes Based on 2-Hydroxy-4-n-octyloxybenzophenone

    Directory of Open Access Journals (Sweden)

    Bharat C. Dixit

    2011-01-01

    Full Text Available Solvent dyes have been prepared by the coupling of diazo solution of different aromatic amines with 2-hydroxy-4-n-octyloxybenzophenone. The resultant dyes were characterized by elemental analysis as well as IR and 1H NMR spectral studies. The UV-Visible spectral data have also been discussed in terms of structure property relationship. The printing of all the dyes on cotton fiber was monitored. The result shows that better hue was obtained on printing on cotton fiber and it is resulted in yellow to reddish brown colorations which showed a good fastness to light, with poor to good fastness to washing, perspiration and sublimation, however it shows poor rubbing fastness.

  6. Functionalization of CNTs surface with phosphonuim based deep eutectic solvents for arsenic removal from water

    Science.gov (United States)

    AlOmar, Mohamed Khalid; Alsaadi, Mohammed Abdulhakim; Hayyan, Maan; Akib, Shatirah; Hashim, Mohd Ali

    2016-12-01

    Herein, we present the use of deep eutectic solvent (DES) as functionalization agents for carbon nanotubes (CNTs) to form novel adsorbents for removal of arsenic ions (As3+) from water. Two DESs systems were prepared using methyltriphenylphosphonium bromide (MTPB) and benzyltriphenylphosphonium chloride (BTPC) as salts, in conjugation with glycerol (Gly) as a hydrogen bond donor. The resulting novel adsorbents were characterized using thermogravimetric analysis (TGA), Zeta potential, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, XRD, EDX, FESEM, and BET surface area. Optimization studies were carried out utilizing RSM-CCD experimental design to estimate the optimum removal conditions for each adsorbent. The adsorption experimental data of both adsorbents were found to fit well with pseudo-second-order kinetics model, as well as with Langmuir and Freundlich adsorption isotherm models. The maximum adsorption capacity of a MTPB-DES-functionalized CNTs adsorbent was 23.4 mg/g.

  7. AIE Based Coumarin Chromophore - Evaluation and Correlation Between Solvatochromism and Solvent Polarity Parameters.

    Science.gov (United States)

    Lanke, Sandip K; Sekar, Nagaiyan

    2016-03-01

    A new class of red emitting extensively conjugated donor-π-acceptor type dyes bearing coumarin units have been synthesized by condensation of 7-(diethylamino)-2-oxo-2 H-chromene-3-carbaldehyde with different active methylenes. All the dyes are characterized by (1)H NMR, (13)C NMR and HRMS spectroscopy. The photophysical behaviour and the relation between structure and properties of the coumarin "push-pull" derivatives were investigated experimentally. The dyes exhibited positive solvatochromism and solvatofluorism in solution of varying polarity. These coumarin dyes show aggregation induced emission properties with red emitting fluorescence. They show absorption in the range of 501-528 and emission in the range of 547-630 nm. We evaluated photophysical properties of coumarin dyes using solvotochromism and solvent dependent shift in the emission wavelength. All the synthesized coumarin dyes COS1-COS4 are showing very good solvatochromic properties.

  8. Mutual diffusion coefficient models for polymer-solvent systems based on the Chapman-Enskog theory

    Directory of Open Access Journals (Sweden)

    R. A. Reis

    2004-12-01

    Full Text Available There are numerous examples of the importance of small molecule migration in polymeric materials, such as in drying polymeric packing, controlled drug delivery, formation of films, and membrane separation, etc. The Chapman-Enskog kinetic theory of hard-sphere fluids with the Weeks-Chandler-Andersen effective hard-sphere diameter (Enskog-WCA has been the most fruitful in diffusion studies of simple fluids and mixtures. In this work, the ability of the Enskog-WCA model to describe the temperature and concentration dependence of the mutual diffusion coefficient, D, for a polystyrene-toluene system was evaluated. Using experimental diffusion data, two polymer model approaches and three mixing rules for the effective hard-sphere diameter were tested. Some procedures tested resulted in models that are capable of correlating the experimental data with the refereed system well for a solvent mass fraction greater than 0.3.

  9. Spectrophotometric Study of Stability Constants of Cr(III, Ni(II and Cu(II Complexes with a Schiff’s Base in Different Solvents

    Directory of Open Access Journals (Sweden)

    Israel Leka Lere

    2013-12-01

    Full Text Available Complexation of Cr(III, Ni(II and Cu(II with para-dimethylaminoanil of ortho-hydroxyphenylglyoxal Schiff’s base in methanol, ethanol and acetone solvents has been studied spectrophotometrically at room temperature (298K. The stoichiometry and stability of the complexes were determined using mole-ratio method. Stability data shows solvent-wise stability order as methanol > ethanol > acetone.

  10. How do evaporating thin films evolve? Unravelling phase-separation mechanisms during solvent-based fabrication of polymer blends

    KAUST Repository

    Wodo, Olga

    2014-10-13

    © 2014 AIP Publishing LLC. Solvent-based fabrication is a flexible and affordable approach to manufacture polymer thin films. The properties of products made from such films can be tailored by the internal organization (morphology) of the films. However, a precise knowledge of morphology evolution leading to the final film structure remains elusive, thus limiting morphology control to a trial and error approach. In particular, understanding when and where phases are formed, and how they evolve would provide rational guidelines for more rigorous control. Here, we identify four modes of phase formation and subsequent propagation within the thinning film during solvent-based fabrication. We unravel the origin and propagation characteristics of each of these modes. Finally, we construct a mode diagram that maps processing conditions with individual modes. The idea introduced here enables choosing processing conditions to tailor film morphology characteristics and paves the ground for a deeper understanding of morphology control with the ultimate goal of precise, yet affordable, morphology manipulation for a large spectrum of applications.

  11. Development of green betaine-based deep eutectic solvent aqueous two-phase system for the extraction of protein.

    Science.gov (United States)

    Li, Na; Wang, Yuzhi; Xu, Kaijia; Huang, Yanhua; Wen, Qian; Ding, Xueqin

    2016-05-15

    Six kinds of new type of green betaine-based deep eutectic solvents (DESs) have been synthesized. Deep eutectic solvent aqueous two-phase systems (DES-ATPS) were established and successfully applied in the extraction of protein. Betaine-urea (Be-U) was selected as the suitable extractant. Single factor experiments were carried out to determine the optimum conditions of the extraction process, such as the salt concentration, the mass of DES, the separation time, the amount of protein, the temperature and the pH value. The extraction efficiency could achieve to 99.82% under the optimum conditions. Mixed sample and practical sample analysis were discussed. The back extraction experiment was implemented and the back extraction efficiency could reach to 32.66%. The precision experiment, repeatability experiment and stability experiment were investigated. UV-vis, FT-IR and circular dichroism (CD) spectra confirmed that the conformation of protein was not changed during the process of extraction. The mechanisms of extraction were researched by dynamic light scattering (DLS), the measurement of the conductivity and transmission electron microscopy (TEM). DES-protein aggregates and embraces phenomenon play considerable roles in the separation process. All of these results indicated that betaine-based DES-ATPS may provide a potential substitute new method for the separation of proteins.

  12. Advanced solvent based methods for molecular characterization of soil organic matter by high-resolution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tfaily, Malak M.; Chu, Rosalie K.; Tolic, Nikola; Roscioli, Kristyn M.; Anderton, Christopher R.; Pasa-Tolic, Ljiljana; Robinson, Errol W.; Hess, Nancy J.

    2015-05-19

    Soil organic matter (SOM) a complex, heterogeneous mixture of above and belowground plant litter and animal and microbial residues at various degrees of decomposition, is a key reservoir for carbon (C) and nutrient biogeochemical cycling in soil based ecosystems. A limited understanding of the molecular composition of SOM limits the ability to routinely decipher chemical processes within soil and predict accurately how terrestrial carbon fluxes will response to changing climatic conditions and land use. To elucidate the molecular-level structure of SOM, we selectively extracted a broad range of intact SOM compounds by a combination of different organic solvents from soils with a wide range of C content. Our use of Electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and a suite of solvents with varying polarity significantly expands the inventory of the types of organic molecules present in soils. Specifically, we found that hexane is selective for lipid-like compounds with very low O:C ratios; water was selective for carbohydrates with high O:C ratios; acetonitrile preferentially extracts lignin, condensed structures, and tannin poly phenolic compounds with O:C > 0.5; methanol has higher selectivity towards compounds characterized with low O:C < 0.5; and hexane, MeOH, ACN and water solvents increase the number and types of organic molecules extracted from soil for a broader range of chemically diverse soil types. Our study of SOM molecules by ESI-FTICR MS revealed new insight into the molecular-level complexity of organics contained in soils.

  13. A solvent-controlled switch of manganese complex assemblies with a beta-diketonate-based ligand.

    Science.gov (United States)

    Aromí, Guillem; Gamez, Patrick; Roubeau, Olivier; Berzal, Paula Carrero; Kooijman, Huub; Spek, Anthony L; Driessen, Willem L; Reedijk, Jan

    2002-07-15

    The coordination properties of the new polynucleating ligand H(3)L1 (1,3-bis(3-oxo-3-phenylpropionyl)-2-hydroxy-5-methylbenzene) with Mn(II/III) are described. Depending on the solvent used, the reaction of H(3)L1 with Mn(OAc)(2) yields either of the two new multinuclear assemblies [Mn(2)(HL1)(2)(py)(4)] (1) and [Mn(3)(HL1)(3)] (2), as revealed by X-ray crystallography. The structure of 2 is remarkable in that it shows a unique asymmetric triple-stranded helicate. Complexes 1 and 2 can be interconverted by controlling the solvent of the reaction system, and therefore, this ensemble constitutes an interesting externally addressable switch. In the presence of Mn(III)/pyridine, partial degradation of H(3)L1 occurs via oxidative cleavage, and the new complex [Mn(2)(L2)(2)(py)(4)] (3) is formed. The crystal structure of this complex has shown the fully deprotonated form of the new donor H(3)L2 (3-(3-oxo-3-phenylpropionyl)-5-methylsalicylic acid). From the same reaction, the Mn(II) complex 1 is also obtained. A rational synthesis of H(3)L2 is reported, and this has been used to prepare 3 in high yields, directly from its components. Variable-temperature magnetic susceptibility (chi(m)) measurements were performed on complexes 1-3 under a magnetic field of 1 kG. The data for each complex were fit to the appropriate chi(m) vs T theoretical equation, respectively. In 1, the Mn(II) ions are uncoupled, with g = 2.01. The data from 2 were fit by assuming the presence of an exchange coupled Mn(II)...Mn(II) pair next to a magnetically isolated Mn(II) center. The fit gave J = -2.75 cm(-1), g(12) = 1.97, and g(3) = 1.92, respectively. In 3, two models fit the experimental data. In the most satisfactory, the Mn(III) ions are coupled antiferromagnetically with J = -1.48 cm(-1) and g = 1.98 and a term for weak ferromagnetic intermolecular exchange is included with zJ' = 0.39 cm(-1). The other model contemplates the presence of two uncoupled zero field split Mn(III) ions.

  14. Dipole Strength Calculation Based on Two-Level System Approximation to Study Q/B-Band Intensity Ratio of ZnTBP in Solvent

    Science.gov (United States)

    Rusydi, Febdian; Shukri, Ganes; Saputro, Adithya G.; Agusta, Mohammad K.; Dipojono, Hermawan K.; Suprijadi, Suprijadi

    2017-04-01

    We study the Q/B-band dipole strength of zinc tetrabenzoporphyrin (ZnTBP) using density functional theory (DFT) in various solvents. The solvents are modeled using the polarized continuum model (PCM). The dipole strength calculations are approached by a two-level system, where the Q-band is described by the HOMO → LUMO electronic transition and the B-band by the HOMO-1 → LUMO electronic transition. We compare the results with the experimental data of the Q/B-band intensity ratio. We also perform time-dependent DFT coupled with PCM to calculate the Q/B-band oscillator strength ratio of ZnTBP. The results of both methods show a general trend with respect to the experimental Q/B-band intensity ratio in solvents, except for the calculation in the water solvent. Even so, the approximation is a good starting point for studying the UV-vis spectrum based on DFT study alone.

  15. Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives.

    Science.gov (United States)

    Schulz, Gisela L; Urdanpilleta, Marta; Fitzner, Roland; Brier, Eduard; Mena-Osteritz, Elena; Reinold, Egon; Bäuerle, Peter

    2013-01-01

    The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu 4 as donor in conjunction with PC61BM as acceptor is described. Power conversion efficiencies up to 3.0% and external quantum efficiencies up to 40% were obtained through the use of 1-chloronaphthalene as solvent additive in the fabrication of the photovoltaic devices. Furthermore, atomic force microscopy investigations of the photoactive layer gave insight into the distribution of donor and acceptor within the blend. The unique combination of solubility and thermal stability of DCV5T-Bu 4 also allows for fabrication of organic solar cells by vacuum deposition. Thus, we were able to perform a rare comparison of the device characteristics of the solution-processed DCV5T-Bu 4 :PC61BM solar cell with its vacuum-processed DCV5T-Bu 4 :C60 counterpart. Interestingly in this case, the efficiencies of the small-molecule organic solar cells prepared by using solution techniques are approaching those fabricated by using vacuum technology. This result is significant as vacuum-processed devices typically display much better performances in photovoltaic cells.

  16. Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives

    Directory of Open Access Journals (Sweden)

    Gisela L. Schulz

    2013-10-01

    Full Text Available The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu4 as donor in conjunction with PC61BM as acceptor is described. Power conversion efficiencies up to 3.0% and external quantum efficiencies up to 40% were obtained through the use of 1-chloronaphthalene as solvent additive in the fabrication of the photovoltaic devices. Furthermore, atomic force microscopy investigations of the photoactive layer gave insight into the distribution of donor and acceptor within the blend. The unique combination of solubility and thermal stability of DCV5T-Bu4 also allows for fabrication of organic solar cells by vacuum deposition. Thus, we were able to perform a rare comparison of the device characteristics of the solution-processed DCV5T-Bu4:PC61BM solar cell with its vacuum-processed DCV5T-Bu4:C60 counterpart. Interestingly in this case, the efficiencies of the small-molecule organic solar cells prepared by using solution techniques are approaching those fabricated by using vacuum technology. This result is significant as vacuum-processed devices typically display much better performances in photovoltaic cells.

  17. Tuning Microparticle Porosity during Single Needle Electrospraying Synthesis via a Non-Solvent-Based Physicochemical Approach

    Directory of Open Access Journals (Sweden)

    Yuan Gao

    2015-12-01

    Full Text Available Porous materials, especially microparticles (MP, are utilized in almost every field of engineering and science, ranging from healthcare materials (drug delivery to tissue engineering to environmental engineering (biosensing to catalysis. Here, we utilize the single needle electrospraying technique (as opposed to complex systems currently in development to prepare a variety of poly(ε-caprolactone (PCL MPs with diverse surface morphologies (variation in pore size from 220 nm to 1.35 µm and architectural features (e.g., ellipsoidal, surface lamellar, Janus lotus seedpods and spherical. This is achieved by using an unconventional approach (exploiting physicochemical properties of a series of non-solvents as the collection media via a single step. Sub-micron pores presented on MPs were visualized by electron microscopy (demonstrating a mean MP size range of 7–20 μm. The present approach enables modulation in morphology and size requirements for specific applications (e.g., pulmonary delivery, biological scaffolds, multi-stage drug delivery and biomaterial topography enhancement. Differences in static water contact angles were observed between smooth and porous MP-coated surfaces. This reflects the hydrophilic/hydrophobic properties of these materials.

  18. Evaluating the complexation behavior and regeneration of boron selective glucaminium-based ionic liquids when used as extraction solvents

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Manishkumar D.; Steyer, Daniel J. [Department of Chemistry, School of Green Chemistry and Engineering, University of Toledo, Toledo, OH (United States); Anderson, Jared L., E-mail: Jared.Anderson@UToledo.edu [Department of Chemistry, School of Green Chemistry and Engineering, University of Toledo, Toledo, OH (United States)

    2012-08-31

    Highlights: Black-Right-Pointing-Pointer Glucaminium-based ILs exhibit high selectivity for boron species using DLLME. Black-Right-Pointing-Pointer The concentration of glucaminium-based IL affects type of boron complex formed. Black-Right-Pointing-Pointer Use of 0.1 M HCl allows for regeneration of the IL solvent following extraction. Black-Right-Pointing-Pointer Selectivity of the glucaminium-based ILs for boron species in seawater is similar to Milli-Q water. - Abstract: Glucaminium-based ionic liquids are a new class of solvents capable of extracting boron-species from water with high efficiency. The complexation behavior of these ILs with borate was thoroughly studied using {sup 11}B NMR. Two different complexes, namely, monochelate complex and bischelate complex, were observed. {sup 11}B NMR was used extensively to determine the formation constants for monochelate and bischelate complexes. The IL concentration was observed to have a significant effect on the IL-borate complexes. Using an in situ dispersive liquid-liquid microextraction (in situ DLLME) method, the extraction efficiency for boron species was increased dramatically when lithium bis[(trifluoromethyl)sulfonyl]imide (LiNTf{sub 2}) was used as the metathesis salt in an aqueous solution containing 0.1 M sodium chloride. IL regeneration after extraction was achieved using 0.1 M hydrochloric acid. The extraction efficiency of boron species was consistent when the IL was employed after three regeneration cycles. The selectivity of the IL for boron species in synthetic seawater samples was similar to performing the same extraction from Milli-Q water samples.

  19. Oxidation of Aliphatic Alcohols by Using Precious Metals Supported on Hydrotalcite under Solvent- and Base-Free Conditions.

    Science.gov (United States)

    He, Yufei; Feng, Junting; Brett, Gemma L; Liu, Yanan; Miedziak, Peter J; Edwards, Jennifer K; Knight, David W; Li, Dianqing; Hutchings, Graham J

    2015-10-12

    Precious metal nanoparticles supported on magnesium-aluminum hydrotalcite (HT), TiO2 , and MgO were prepared by sol immobilization and assessed for the catalytic oxidation of octanol, which is a relatively unreactive aliphatic alcohol, with molecular oxygen as the oxidant under solvent- and base-free conditions. Compared with the TiO2 - and MgO-supported catalysts, platinum HT gave the highest activity and selectivity towards the aldehyde. The turnover number achieved for the platinum HT catalyst was >3700 after 180 min under mild reaction conditions. Moreover, the results for the oxidation of different substrates indicate that a specific interaction of octanal with the platinum HT catalyst could lead to deactivation of the catalyst.

  20. Solvent cleaning system and method for removing contaminants from solvent used in resin recycling

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2009-01-06

    A two step solvent and carbon dioxide based system that produces essentially contaminant-free synthetic resin material and which further includes a solvent cleaning system for periodically removing the contaminants from the solvent so that the solvent can be reused and the contaminants can be collected and safely discarded in an environmentally safe manner.

  1. Two-dimensional assembly based on flow supramolecular chemistry: kinetic control of molecular interactions under solvent diffusion.

    Science.gov (United States)

    Numata, Munenori; Kozawa, Tomohiro

    2014-05-19

    Self-assembly of porphyrin molecules can be controlled kinetically to form structures with lengths extending from the nano- to the micrometer scale, through a programmed solvent-diffusion process in designed microflow spaces. Temporal solvent structures generated in the microflow were successfully transcribed into molecular architectures.

  2. Application of ultrasound-assisted emulsification microextraction based on applying low-density organic solvent for the determination of organochlorine pesticides in water samples.

    Science.gov (United States)

    Zhang, Yufeng; Lee, Hian Kee

    2012-08-24

    In this study, a polyethylene Pasteur pipette-based ultrasound-assisted emulsification microextraction (USAEME) applying low-density organic solvent was successfully developed for the extraction of trace levels of organochlorine pesticides (OCPs) in water samples and followed by gas chromatography-mass spectrometry (GC-MS) analysis. In this approach, a polyethylene Pasteur squeeze-type pipette was employed as a convenient extraction device and ultrasound radiation was applied to accelerate the emulsification of low-density organic solvent in aqueous solutions to enhance the microextraction efficiency of OCPs in water samples. Thirty microliters of extraction solvent (isooctane), of lower density than water, were injected into the aqueous sample solution held in the pipette. The latter was then immersed in an ultrasound water bath to form an emulsion. After 30s extraction, phase separation was achieved by centrifugation. The upper layer (isooctane) was collected and analyzed by GC-MS. No disperser solvent was required in this procedure. Significantly, fast analysis and high extraction efficiency were achieved. Another feature of the procedure was the use of the pipette as the extraction device, which permitted less dense than water organic solvent to be used as extraction solvent. This method broadens the applicability of USAEME to a wider range of solvent. Additionally, carry-over problems were avoided with the use of the disposable pipette. Parameters affecting the efficiency of polyethylene Pasteur pipette-based USAEME, such as the extraction solvent, extraction solvent volume, extraction and centrifugation time, ionic strength and extraction temperature were investigated. Under the optimum conditions, the proposed method provided good enrichment factors (EFs) in the range of 128 and 328, with relative standard deviations (RSDs) ranging from 2.7% to 12.4%. The limits of detection were in the range of 0.8 and 10ng/L depending on the analytes. The linearities were

  3. Colorimetric Humidity and Solvent Recognition Based on a Cation-Exchange Clay Mineral Incorporating Nickel(II)-Chelate Complexes.

    Science.gov (United States)

    Hosokawa, Hitoshi; Mochida, Tomoyuki

    2015-12-01

    Solvatochromic nickel(II) complexes with diketonato and diamine ligands were incorporated into a saponite clay by ion exchange, and their colorimetric humidity- and solvent-recognition properties were investigated. These powders exhibit color change from red to blue-green depending on humidity, and the detection range can be controlled by modifying the metal complex. The humidity response takes advantage of the humidity-dependent water content in clay and the coordination of water molecules to the metal complex in equilibrium. The addition of organic solvents to the powders causes a color change to occur, varying from red to blue-green depending on the donor number of the solvent, thereby enabling solvent recognition. In the clay, the affinity of less sterically hindered complexes to water or solvent molecules is decreased compared with that in solution because the cationic complexes interact with the anionic layers in the clay. Incorporating diethylene glycol into the materials produced thermochromic powders.

  4. Magnetic graphene oxide modified with choline chloride-based deep eutectic solvent for the solid-phase extraction of protein

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yanhua; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Pan, Qi; Wang, Ying; Ding, Xueqin; Xu, Kaijia; Li, Na; Wen, Qian

    2015-06-02

    Highlights: • A strategy for extraction of protein based on DES-coated magnetic graphene oxide. • The deep eutectic solvents were based on choline chloride. • Bovine serum albumin was used as the analyte. • The material prepared works for the acidic but not the basic or the neutral proteins. - Abstract: Four kinds of green deep eutectic solvents (DESs) based on choline chloride (ChCl) have been synthesized and coated on the surface of magnetic graphene oxide (Fe{sub 3}O{sub 4}@GO) to form Fe{sub 3}O{sub 4}@GO-DES for the magnetic solid-phase extraction of protein. X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FESEM) and thermal gravimetric analysis (TGA) were employed to characterize Fe{sub 3}O{sub 4}@GO-DES, and the results indicated the successful preparation of Fe{sub 3}O{sub 4}@GO-DES. The UV–vis spectrophotometer was used to measure the concentration of protein after extraction. Single factor experiments proved that the extraction amount was influenced by the types of DESs, solution temperature, solution ionic strength, extraction time, protein concentration and the amount of Fe{sub 3}O{sub 4}@GO-DES. Comparison of Fe{sub 3}O{sub 4}@GO and Fe{sub 3}O{sub 4}@GO-DES was carried out by extracting bovine serum albumin, ovalbumin, bovine hemoglobin and lysozyme. The experimental results showed that the proposed Fe{sub 3}O{sub 4}@GO-DES performs better than Fe{sub 3}O{sub 4}@GO in the extraction of acidic protein. Desorption of protein was carried out by eluting the solid extractant with 0.005 mol L{sup −1} Na{sub 2}HPO{sub 4} contained 1 mol L{sup −1} NaCl. The obtained elution efficiency was about 90.9%. Attributed to the convenient magnetic separation, the solid extractant could be easily recycled.

  5. Effects of solvents and dosing procedure on chemical toxicity in cell-based in vitro assays.

    NARCIS (Netherlands)

    Tanneberger, K.; Rico Rico, A.; Kramer, N.I.; Busser, F.J.M.; Hermens, J.L.M.; Schirmer, K.

    2010-01-01

    Due to the implementation of new legislation, such as REACh, a dramatic increase of animal use for toxicity testing is expected and the search for alternatives is timely. Cell-based in vitro assays are promising alternatives. However, the behavior of chemicals in these assays is still poorly underst

  6. A toxic organic solvent-free technology for the preparation of PEGylated paclitaxel nanosuspension based on human serum albumin for effective cancer therapy.

    Science.gov (United States)

    Yin, Tingjie; Dong, Lihui; Cui, Bei; Wang, Lei; Yin, Lifang; Zhou, Jianping; Huo, Meirong

    2015-01-01

    Clinically, paclitaxel (PTX) is one of most commonly prescribed therapies against a wide range of solid neoplasms. Despite its success, the clinical applicability of PTX (Taxol) is severely hampered by systemic toxicities induced by Cremophor EL. While attempts to bypass the need for Cremophor EL have been developed through platforms such as Abraxane, nab relies heavily on the use of organic solvents, namely, chloroform. The toxicity introduced by residual chloroform poses a potential risk to patient health. To mitigate the toxicities of toxic organic solvent-based manufacture methods, we have designed a method for the formulation of PTX nanosuspensions (PTX-PEG [polyethylene glycol]-HSA [human serum albumin]) that eliminates the dependence on toxic organic solvents. Coined the solid-dispersion technology, this technique permits the dispersion of PTX into PEG skeleton without the use of organic solvents or Cremophor EL as a solubilizer. Once the PTX-PEG dispersion is complete, the dispersion can be formulated with HSA into nanosuspensions suitable for intravenous administration. Additionally, the incorporation of PEG permits the prolonged circulation through the steric stabilization effect. Finally, HSA-mediated targeting permits active receptor-mediated endocytosis for enhanced tumor uptake and reduced side effects. By eliminating the need for both Cremophor EL and organic solvents while simultaneously increasing antitumor efficacy, this method provides a superior alternative to currently accepted methods for PTX delivery.

  7. DFT-based simulations of IR amide I' spectra for a small protein in solution. Comparison of explicit and empirical solvent models.

    Science.gov (United States)

    Grahnen, Johan A; Amunson, Krista E; Kubelka, Jan

    2010-10-14

    Infrared (IR) amide I' spectra are widely used for investigations of the structural properties of proteins in aqueous solution. For analysis of the experimental data, it is necessary to separate the spectral features due to the backbone conformation from those arising from other factors, in particular the interaction with solvent. We investigate the effects of solvation on amide I' spectra for a small 40-residue helix-turn-helix protein by theoretical simulations based on density functional theory (DFT). The vibrational force fields and intensity parameters for the protein amide backbone are constructed by transfer from smaller heptaamide fragments; the side chains are neglected in the DFT calculations. Solvent is modeled at two different levels: first as explicit water hydrogen bonded to the surface amide groups, treated at the same DFT level, and, second, using the electrostatic map approach combined with molecular dynamics (MD) simulation. Motional narrowing of the spectral band shapes due to averaging over the fast solvent fluctuation is introduced by use of the time-averaging approximation (TAA). The simulations are compared with the experimental amide I', including two (13)C isotopically edited spectra, corrected for the side-chain signals. Both solvent models are consistent with the asymmetric experimental band shape, which arises from the differential solvation of the amide backbone. However, the effects of (13)C isotopic labeling are best captured by the gas-phase calculations. The limitations of the solvent models and implications for the theoretical simulations of protein amide vibrational spectra are discussed.

  8. Vortex-assisted low density solvent based demulsified dispersive liquid-liquid microextraction and high-performance liquid chromatography for the determination of organophosphorus pesticides in water samples.

    Science.gov (United States)

    Seebunrueng, Ketsarin; Santaladchaiyakit, Yanawath; Srijaranai, Supalax

    2014-05-01

    A simple, rapid, effective and eco-friendly preconcentration method, vortex-assisted low density solvent based solvent demulsified dispersive liquid-liquid microextraction (VLDS-SD-DLLME), followed by high performance liquid chromatography-diode array detector (HPLC-DAD) analysis, has been developed for the first time for the determination of four organophosphorus pesticides (OPPs) (e.g., azinphos-methyl, parathion-methyl, fenitrothion and diazinon) in environmental water samples. In this preconcentration procedure, an emulsion was obtained after the mixture of extraction solvent (1-dodecanol) and dispersive solvent (acetonitrile, ACN) was injected rapidly into 10 mL of the sample solution. The vortex agitator aided the dispersion of the extraction solvent into the sample solution. After the formation of an emulsion, the demulsifier (ACN) was added, resulting in the rapid separation of the mixture into two phases without centrifugation. Under optimal conditions, the proposed method provided high extraction efficiency (90-99%), good linearity range (0.5-500 ng mL(-1)), low limits of detection (0.25-1 ng mL(-1)) and good repeatability and recoveries were obtained.

  9. Solvent-vapour treatment induced performance enhancement of amplified spontaneous emission based on poly[2-methoxy-5-(2/-ethyl-hexyloxy)-l,4-phenylene vinylene

    Institute of Scientific and Technical Information of China (English)

    Zhang Bo; Hou Yan-Bing; Teng Feng; Lou Zhi-Dong; Liu Xiao-Jun; Hu Bing; Wu Wen-Bin

    2011-01-01

    In this work, performance enhancements of amplified spontaneous emission (ASE) from poly[2-methoxy-5-(2'- ethyl-hexylaxy)-1,4-phenylene vinylene] (MEH-PPV) have been achieved via solvent vapour treatment. Correlations between the morphology of the film and the optical performance of polymer-based ASE are investigated. The active layers are characterised by atomic force microscopy and optical absorption. The results show that the solvent-vapour treatment can induce the MEH-PPV self-organisation into an ordered structure with a smooth surface, leading to enhanced optical gain. Thus the solvent-vapour treatment is a good method for improving the optical properties of the MEH-PPV.

  10. Solvent-Controlled Assembly of ionic Metal-Organic Frameworks Based on Indium and Tetracarboxylate Ligand: Topology Variety and Gas Sorption Properties

    KAUST Repository

    Zheng, Bing

    2016-07-15

    Four Metal-Organic Frameworks (MOFs) based on Indium and tetracarboxylate ligand have been synthesized through regulation of the solvent conditions, the resulted compounds not only exhibited rich structural topologies (pts, soc and unique topologies), but also interesting charge reversal framework features. By regulating the solvent, different building units (indium monomer, trimer) have been generated in situ, and they are connected with the ligand to form ionic frameworks 1-4, respectively. Among the synthesized four ionic frameworks, compounds 3 and 4 could keep their crystallinity upon heating temperature up to 300oC after fully removal of solvent guest molecules, they also exhibit the charge reversal framework features (3 adopts an overall cationic framework, while 4 has an anionic framework). Both compounds 3 and 4 exhibit significant uptake capacity for CO2 and H2, besides that, compounds 3 and 4 also present excellent selective adsorption of CO2 over N2 and CH4.

  11. Multiple testing issues in discriminating compound-related peaks and chromatograms from high frequency noise, spikes and solvent-based nois in LC-MS data sets

    NARCIS (Netherlands)

    Nyangoma, S.O.; Van Kampen, A.A.; Reijmers, T.H.; Govorukhina, N.I; van der Zee, A.G.; Billingham, I.J; Bischoff, Rainer; Jansen, R.C.

    2007-01-01

    Multiple testing issues in discriminating compound-related peaks and chromatograms from high frequency noise, spikes and solvent-based noise in LC-MS data sets.Nyangoma SO, van Kampen AA, Reijmers TH, Govorukhina NI, van der Zee AG, Billingham LJ, Bischoff R, Jansen RC. University of Birmingham. Liq

  12. Solvent effect on H-bond cooperativity factors in ternary complexes of methanol, octan-1-ol, 2,2,2-trifluoroethanol with some bases.

    Science.gov (United States)

    Solomonov, Boris N; Varfolomeev, Mikhail A; Abaidullina, Dilyara I

    2008-03-01

    Cooperative hydrogen bonds in ternary complexes (ROH)(2)...B (ROH-alcohols; B-bases) formed in pure bases (B) and solutions in n-hexane, carbon tetrachloride, benzene and 1,2-dichloroethane were studied by FTIR spectroscopy. Based on the observations, the authors were able to propose an original method of evaluating solvent effects on cooperativity factors in the complexes. Frequencies of cooperative hydrogen bonds OH...B (nu(b)) were determined for ternary complexes of pyridine with aliphatic alcohols (methanol, octan-1-ol) and for 2,2,2-trifluoroethanol with three different bases (acetonitrile, diethyl ether, tetrahydrofuran). The solvent shifts of nu(b) were found to correlate with an empirical thermochemical parameter of the solvent, S(VW). The cooperativity factors were determined for the complexes (ROH)(2)...B in all studied media. It has been found that the cooperativity factors are almost independent of the solvent. In addition, a method was proposed of estimating the frequencies and cooperativity factors for ternary complexes (ROH)(2)...B in the gas phase. It has been found that in gas phase the cooperativity factors are practically the same as in condensed media.

  13. Reaction Mechanism for Direct Proton Transfer from Carbonic Acid to a Strong Base in Aqueous Solution II: Solvent Coordinate-Dependent Reaction Path.

    Science.gov (United States)

    Daschakraborty, Snehasis; Kiefer, Philip M; Miller, Yifat; Motro, Yair; Pines, Dina; Pines, Ehud; Hynes, James T

    2016-03-10

    The protonation of methylamine base CH3NH2 by carbonic acid H2CO3 within a hydrogen (H)-bonded complex in aqueous solution was studied via Car-Parrinello dynamics in the preceding paper (Daschakraborty, S.; Kiefer, P. M.; Miller, Y.; Motro, Y.; Pines, D.; Pines, E.; Hynes, J. T. J. Phys. Chem. B 2016, DOI: 10.1021/acs.jpcb.5b12742). Here some important further details of the reaction path are presented, with specific emphasis on the water solvent's role. The overall reaction is barrierless and very rapid, on an ∼100 fs time scale, with the proton transfer (PT) event itself being very sudden (water solvent changes little until the actual PT occurrence; this results from the very strong driving force for the reaction, as indicated by the very favorable acid-protonated base ΔpKa difference. Further solvent rearrangement follows immediately the sudden PT's production of an incipient contact ion pair, stabilizing it by establishment of equilibrium solvation. The solvent water's short time scale ∼120 fs response to the incipient ion pair formation is primarily associated with librational modes and H-bond compression of water molecules around the carboxylate anion and the protonated base. This is consistent with this stabilization involving significant increase in H-bonding of hydration shell waters to the negatively charged carboxylate group oxygens' (especially the former H2CO3 donor oxygen) and the nitrogen of the positively charged protonated base's NH3(+).

  14. Evaluation of Disposal Concepts for Used Solvents at DoD Bases

    Science.gov (United States)

    1983-02-01

    Occupational Safety and Health Act (OSHA) and Department of Transportation (DOT) regulations also impact the selection of viable 2-4 Table 3. Comercial ...good handling and segregation practices for the used material; and the availability of a comercial organization that can perform the reclamation service...California El Centro Naval Air Facility CaLifornia El Toro Marine Corps Air Station California Fort Ord California George Air Force Base California Hunters

  15. Ionic Liquid Solvent Based on Cyclic Guanidinium Cation for Nucleophilic Displacement Reactions

    Institute of Scientific and Technical Information of China (English)

    LIN Ying-jie; QIU Zhi-ming; DUAN Hai-feng; LI Sheng-hai; ZHANG Suo-bo

    2004-01-01

    The nucleophilic displacement reaction of n-bromooctane and potassium iodide in ionic liquid based on cyclic guanidinium cation(2) was investigated. The kinetic reasult shows that the rate of the reaction is enhanced in ionic liquid (2). The same reaction in [bmim][PF6](1)(where bmim=1-butyl-3-methylimidazolium) was also studied. It was found that as a reaction medium ionic liquid (2) is better than (1) for nucelophilic displacement reactions.

  16. Solvent-assistant self-assembly of an AIE+TICT fluorescent Schiff base for the improved ammonia detection.

    Science.gov (United States)

    Han, Tianyu; Wei, Wei; Yuan, Jing; Duan, Yuai; Li, Yaping; Hu, Liangyu; Dong, Yuping

    2016-04-01

    Solvent-assistant self-assembly of an AIE+TICT fluorescent Schiff base into one-dimensional nanofilaments has been developed. The orientation of the assemblies can be controlled by a simple dewetting process: the filaments are interweaved when the self-assembly process is performed on a horizontal substrate, while tilting the substrate to a tiny angle results in the formation of highly oriented ones with long-range order as verified by microscopic examination. The compound shows remarkable fluorescent response to ammonia gas based on a TICT-LE transition. The self-assembled film presents higher detection sensitivity compared with the non-assembled test paper: the former enables 4.75 times faster response time and 6.86 times lower detection limit than the latter. Furthermore, the former demonstrates better selectivity toward ammonia gas in the presence of various organic amines. The sensing devices also enjoy the advantage of cyclic utilization. The fluorescence of the fumed devices can be converted back into the original state when they are heated at 100 °C for 5 min, as thermal treatment can desorb the ammonia gas that adsorbed in the sensing devices.

  17. The Effect of Temperature on Kinetics and Diffusion Coefficients of Metallocene Derivatives in Polyol-Based Deep Eutectic Solvents.

    Directory of Open Access Journals (Sweden)

    Laleh Bahadori

    Full Text Available The temperature dependence of the density, dynamic viscosity and ionic conductivity of several deep eutectic solvents (DESs containing ammonium-based salts and hydrogen bond donvnors (polyol type are investigated. The temperature-dependent electrolyte viscosity as a function of molar conductivity is correlated by means of Walden's rule. The oxidation of ferrocene (Fc/Fc+ and reduction of cobaltocenium (Cc+/Cc at different temperatures are studied by cyclic voltammetry and potential-step chronoamperometry in DESs. For most DESs, chronoamperometric transients are demonstrated to fit an Arrhenius-type relation to give activation energies for the diffusion of redox couples at different temperatures. The temperature dependence of the measured conductivities of DES1 and DES2 are better correlated with the Vogel-Tamman-Fulcher equation. The kinetics of the Fc/Fc+ and Cc+/Cc electrochemical systems have been investigated over a temperature range from 298 to 338 K. The heterogeneous electron transfer rate constant is then calculated at different temperatures by means of a logarithmic analysis. The glycerol-based DES (DES5 appears suitable for further testing in electrochemical energy storage devices.

  18. Preparation and pharmaceutical evaluation of acetaminophen nano-fiber tablets: Application of a solvent-based electrospinning method for tableting.

    Science.gov (United States)

    Hamori, Mami; Nagano, Kana; Kakimoto, Sayaka; Naruhashi, Kazumasa; Kiriyama, Akiko; Nishimura, Asako; Shibata, Nobuhito

    2016-03-01

    In this study, we developed nano-fiber-based tablets with acetaminophen (AAP; LogPow=0.51) for controlled-release delivery systems and evaluated in vitro drug dissolution and in vivo pharmacokinetics in rats. Nano-fibers made from methacrylic acid copolymer S (MAC; EUDRAGIT S100) and containing AAP were prepared using a solvent-based electrospinning (ES) method. In vitro dissolution rate profiles of AAP showed tableting pressure-dependent decreases and pH-dependent increases. The results of tablet tracking by X-ray irradiation showed tablets based on MAC nano-fibers did not disintegrate in the upper intestinal lumen and had the properties of a long-term-acting tablet. In addition, the in vitro release profiles of AAP from nano-fiber tablets prepared by dissolving MAC with AAP (NFT), nano-fiber tablets prepared by adsorbing AAP to drug-free MAC nano-fibers (NFTadso), and tablets prepared by adsorbing half the amount of AAP to MAC nano-fibers containing the remaining amount of AAP (NFThalf) showed independent controlled-release aspects of AAP compared with physical mixture tablets (PMT). In vivo pharmacokinetic studies in rats after intraduodenal administration of 14 mg/rat AAP in NFT, NFTadso, and NFThalf demonstrated that all these tablets based on MAC nano-fibers showed sustained-release profiles compared with PMT, and showed ultra-sustained release properties for AAP. These new tablets based on MAC nano-fibers did not disintegrate in the intestine in the lower pH region, and the tablets could regulate the release of AAP in a pH-dependent manner. The ES method is a useful technique to prepare nano-fibers and showed promising results as an oral delivery system for sustained-release regulation.

  19. Electroplated Fe-Co-Ni films prepared from deep-eutectic-solvent-based plating baths

    Directory of Open Access Journals (Sweden)

    Takeshi Yanai

    2016-05-01

    Full Text Available We fabricated soft magnetic films from DES-based plating baths, and investigated magnetic properties of the plated films. The plating baths were obtained by stirring the mixture of choline chloride, ethylene glycol, FeCl2 ⋅ 4H2O, NiCl2 ⋅ 6H2O and CoCl2 ⋅ 6H2O. The composition of the electroplated film depended on the amount of the reagent in the plating bath, and we consequently obtained the films with various composition. The current efficiency of the plating process shows high values (> 88 % in the wide composition range. The soft magnetic films with low coercivity were obtained at the Fe compositions of ≈ 30 at.% and > 80 at.%, and we found that low coercivity could be realized by the control of the film composition. We also found that the Fe-rich films prepared from DES-based plating bath have some advantages as a soft magnetic phase for a nanocomposite magnet due to their high saturation magnetization and very fine crystal structure.

  20. In silico study of amphiphilic nanotubes based on cyclic peptides in polar and non-polar solvent

    DEFF Research Database (Denmark)

    Vijayakumar, Vinodhkumar; Vijayaraj, Ramadoss; Peters, Günther H.J.

    2016-01-01

    The stability of cyclic peptide assemblies (CPs) forming a macromolecular nanotube structure was investigated in solvents of different polarity using computational methods. The stability and structure of the complexes were studied using traditional molecular dynamics (MD). Energy of dissociation ...

  1. A Selenium-Based Ionic Liquid as a Recyclable Solvent for the Catalyst-Free Synthesis of 3-Selenylindoles

    Directory of Open Access Journals (Sweden)

    Eder J. Lenardão

    2013-04-01

    Full Text Available The ionic liquid 1-butyl-3-methylimidazolium methylselenite, [bmim][SeO2(OCH3], was successfully used as solvent in the catalyst-free preparation of 3-arylselenylindoles by the reaction of indole with ArSeCl at room temperature. The products were obtained selectively in good yields without the need of any additive and the solvent was easily reused for several cycles with good results.

  2. Reactions and Separations in Green Solvents

    NARCIS (Netherlands)

    Van Spronsen, J.

    2010-01-01

    Most chemical processes involve solvents in the reaction and the separation step. These solvents give rise to a heavy environmental and economical burden. Moreover, these solvents are based on non-sustainable resources like petroleum. The aim of this thesis has been to develop a number of alternativ

  3. Solvent control: dinuclear versus tetranuclear complexes of a bis-tetradentate pyrimidine-based ligand.

    Science.gov (United States)

    Gobeze, Worku A; Milway, Victoria A; Moubaraki, Boujemaa; Murray, Keith S; Brooker, Sally

    2012-08-28

    A new bis-tetradentate acyclic amine ligand L(Et) has been synthesized from 4,6-bis(aminomethyl)-2-phenylpyrimidine and 2-vinylpyridine. Dinuclear complexes, Mn(II)(2)L(Et)(MeCN)(H(2)O)(3)(ClO(4))(4) (1), Fe(II)(2)L(Et)(H(2)O)(4)(BF(4))(4) (2), Co(II)(2)L(Et)(H(2)O)(3)(MeCN)(2)(BF(4))(4) (3), Ni(II)(2)L(Et)(H(2)O)(4)(BF(4))(4) (4), Ni(II)(2)L(Et)(H(2)O)(4)(ClO(4))(4)·8H(2)O (4'), Cu(II)(2)L(Et)(BF(4))(4)·MeCN (5), Zn(II)(2)L(Et)(BF(4))(2)(BF(4))(2)·½MeCN (6), were obtained from 1 : 2 reactions of L(Et) and the appropriate metal salts in MeCN, whereas in MeOH tetranuclear complexes, Mn(II)(4)(L(Et))(2)(OH)(4)(ClO(4))(4) (7), Fe(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·5/2H(2)O (8), Co(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·3H(2)O (9), Ni(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·4H(2)O (10), Cu(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·3H(2)O (11) and Zn(II)(4)(L(Et))(2)(F)(4)(BF(4))(4) (12), result. Six complexes have been structurally characterized: in all cases each L(Et) is bis-tetradentate and provides a pyrimidine bridge between two metal centres. As originally anticipated, complexes 1, 4' and 6 are dinuclear, while 9, 10 and 12 are revealed to be tetranuclear, with two M(2)(L(Et))(4+) moieties bridged by two pairs of fluoride anions. Weak to moderate antiferromagnetic coupling between the metal centres is a feature of complexes 2, 3, 4, 8, 9 and 10. The dinuclear complexes 1-6 undergo multiple, mostly irreversible, redox processes. However, the pyrimidine-based dicopper(II) complex 5 undergoes a two electron quasi-reversible reduction, Cu(II)(2)→ Cu(I)(2), and this occurs at a more positive potential [E(m) = +0.11 V (E(pc) = -0.03 and E(pa) = +0.26 V) vs. 0.01 M AgNO(3)/Ag] than for either of the dicopper(II) complexes of the analogous pyrazine-based ligands.

  4. Reversible structural transformations in a Co(II)-based 2D dynamic metal-organic framework showing selective solvent uptake

    Indian Academy of Sciences (India)

    Sanjog S Nagarkar; Sujit K Ghosh

    2015-04-01

    A Co(II)-based two-dimensional (2D) metal-organic framework (MOF) [Co(pca)(bdc)0.5(H2O)2] (1) {pca = pyrazine carboxylic acid, and bdc = 1,4-benzene dicarboxylic acid} was synthesized solvothermally. The compound loses the coordinated lattice water molecules on heating which is accompanied by solidstate structural transformation to yield dehydrated phase [Co(pca)(bdc)0.5] (1′). The hydrated structure can be regained by exposing 1′ to water vapour (1′′). These reversible solid-state structural transformations are accompanied by a visible colour change in the material. The dehydrated compound also shows highly selective water uptake over other solvents like MeOH, EtOH, THF. This selective water uptake can be ascribed to the high affinity of polar water molecule towards the open metal site created on heating. The present report provides important insights into the reversible structural transformations observed due to variable coordination number of the central metal ion and transformability of the framework. The selective water uptake over alcohols along with visible colour change demonstrates the potential of the present compound in bio-alcohol purification.

  5. Design and synthesis of two luminescent Zn(II)-based coordination polymers with different structures regulated by different solvent system

    Science.gov (United States)

    Wu, Wei-Ping; Wen, Gui-Lin; Liao, Yi; Wang, Jun; Lu, Lu; Wu, Yu; Xie, Bin

    2016-08-01

    Two new coordination polymers (CPs) [Zn(HL)(H2O)]n (1) and [Zn3(L)2(H2O)2]n·(H2O)n (2), based on a multifunctional ligand combined carboxylate groups and a nitrogen donor group 5-(6-carboxypyridin-2-yl)isophthalic acid (H3L), have been synthesized under different solvent media and fully characterized by powder X-ray diffraction (PXRD), infrared (IR) spectra, elemental analyses (EA) and thermogravimetric analyses (TGA). Single-crystal X-ray diffraction analysis reveals that 1 shows 1D dimeric chain structure, while 2 gives a 3D dense packing framework. Topology analysis illustrates that 2 can be simplified as a 3-nodal net (4, 5, 6-connected net) with the point symbol of {44·62}{46·64}2{48·66·8}. In addition, solid state luminescent properties of two complexes have also been studied in detail, which may act as the potential optical materials.

  6. Experimental study of solvent-based emulsion injection to enhance heavy oil recovery in Alaska North Slope area

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, F.; Mamora, D. [Texas A and M Univ., College Station, TX (United States)

    2010-07-01

    This study examined the feasibility of using a chemical enhanced oil recovery method to overcome some of the technical challenges associated with thermal recovery in the Alaska North Slope (ANS). This paper described the second stage research of an experimental study on nano-particle and surfactant-stabilized solvent-based emulsions for the ANS area. Four successful core flood experiments were performed using heavy ANS oil. The runs included water flooding followed by emulsion flooding; and pure emulsion injection core flooding. The injection rate and core flooding temperature remained constant and only 1 PV micro-emulsion was injected after breakthrough under water flooding or emulsion flooding. Oil recovery increased by 26.4 percent from 56.2 percent original oil in place (OOIP) with waterflooding to 82.6 percent OOIP with injection of emulsion following water flooding. Oil recovery was slightly higher with pure emulsion flooding, at 85.8 percent OOIP. The study showed that low permeability generally resulted in a higher shear rate, which is favourable for in-situ emulsification and higher displacement efficiency. 11 refs., 4 tabs., 20 figs.

  7. Development of an Analytical Method Based on Temperature Controlled Solid-Liquid Extraction Using an Ionic Liquid as Solid Solvent

    Directory of Open Access Journals (Sweden)

    Zhongwei Pan

    2015-12-01

    Full Text Available At the present paper, an analytical method based on temperature controlled solid-liquid extraction (TC-SLE utilizing a synthesized ionic liquid, (N-butylpyridinium hexafluorophosphate, [BPy]PF6, as solid solvent and phenanthroline (PT as an extractant was developed to determine micro levels of Fe2+ in tea by PT spectrophotometry. TC-SLE was carried out in two continuous steps: Fe2+ can be completely extracted by PT-[BPy]PF6 or back-extracted at 80 °C and the two phases were separated automatically by cooling to room temperature. Fe2+, after back-extraction, needs 2 mol/L HNO3 as stripping agent and the whole process was determined by PT spectrophotometry at room temperature. The extracted species was neutral Fe(PTmCl2 (m = 1 according to slope analysis in the Fe2+-[BPy]PF6-PT TC-SLE system. The calibration curve was Y = 0.20856X − 0.000775 (correlation coefficient = 0.99991. The linear calibration range was 0.10–4.50 μg/mL and the limit of detection for Fe2+ is 7.0 × 10−2 μg/mL. In this method, the contents of Fe2+ in Tieguanyin tea were determined with RSDs (n = 5 3.05% and recoveries in range of 90.6%–108.6%.

  8. Optical sensor based on hybrid FBG/titanium dioxide coated LPFG for monitoring organic solvents in edible oils.

    Science.gov (United States)

    Coelho, Luís; Viegas, Diana; Santos, José Luís; de Almeida, José Manuel Marques Martins

    2016-01-01

    A hybrid optical sensing scheme based on a fiber Bragg grating (FBG) combined with a titanium dioxide coated long period fiber grating (LPFG) for monitoring organic solvents in high refractive index edible oils is reported. In order to investigate and optimize the sensor performance, two different FBG/LPFG interrogation systems were investigated. The readout of the sensor was implemented using either the wavelength shift of the LPFG resonance dip or the variation in the optical power level of the reflected/transmitted light at the FBG wavelength peak, which in turn depends on the wavelength position of the LPFG resonance. Hexane concentrations up to 20%V/V, corresponding to the refractive index range from 1.451 to 1.467, were considered. For the transmission mode of operation, sensitivities of 1.41 nm/%V/V and 0.11 dB/%V/V, with resolutions of 0.58%V/V and 0.29%V/V, were achieved when using the LPFG wavelength shift and the FBG transmitted optical power, respectively. For the FBG reflection mode of operation, a sensitivity of 0.07 dB/%V/V and a resolution better than 0.16%V/V were estimated.

  9. Non-flammable electrolytes based on trimethyl phosphate solvent for lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    HU Chuan-yue; LI Xin-hai

    2005-01-01

    The properties of trimethyl phosphate(TMP)-based nonflammable electrolytes with LiPF6 as solute were investigated using graphite anode and LiCoO2 cathode. The effect of TMP on non-flammability of electrolytes was also evaluated. It is found that the TMP reduction decomposition on graphite electrode at the potential of 1.3V (vs Li/Li+) is suppressed with ethylene carbonate(EC), dimethyl carbonate(DMC) and ethylmethyl carbonate(EMC) cosolvents and vinylene carbonate(VC) additives. The results show that the non-flammable electrolyte of 1mol/L LiPF6 61%(EC1.5-DMC1.0-EMC1.0)-39% TMP has good electrochemical properties. The discharge capacities of half-cells after 20 cycles are 254.8mA·h/g for Li/graphite and 144.1mA·h/g for Li/LiCoO2. The graphite/LiCoO2 prismatic lithium-ion cell delivers a discharge capacity of 131mA·h/g at first cycle. With an addition of 4%VC to this non-flammable electrolyte, a discharge capacity of 134mA·h/g at first cycle and a capacity ratio of 84.3% after 50 cycles are obtained for prismatic lithium-ion batteries. Furthermore, a nail penetration test demonstrates that the safety of prismatic lithium-ion batteries is dramatically improved by using TMP-containing non-flammable electrolytes.

  10. Differentiation of Chemical Components in a Binary Solvent Vapor Mixture Using Carbon/Polymer Composite-Based Chemiresistors

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sanjay V.; Jenkins, Mark W.; Hughes, Robert C.; Yelton, W. Graham; Ricco, Antonio J.

    1999-07-19

    We demonstrate a ''universal solvent sensor'' constructed from a small array of carbon/polymer composite chemiresistors that respond to solvents spanning a wide range of Hildebrand volubility parameters. Conductive carbon particles provide electrical continuity in these composite films. When the polymer matrix absorbs solvent vapors, the composite film swells, the average separation between carbon particles increases, and an increase in film resistance results, as some of the conduction pathways are broken. The adverse effects of contact resistance at high solvent concentrations are reported. Solvent vapors including isooctane, ethanol, dlisopropyhnethylphosphonate (DIMP), and water are correctly identified (''classified'') using three chemiresistors, their composite coatings chosen to span the full range of volubility parameters. With the same three sensors, binary mixtures of solvent vapor and water vapor are correctly classified, following classification, two sensors suffice to determine the concentrations of both vapor components. Polyethylene vinylacetate and polyvinyl alcohol (PVA) are two such polymers that are used to classify binary mixtures of DIMP with water vapor; the PVA/carbon-particle-composite films are sensitive to less than 0.25{degree}A relative humidity. The Sandia-developed VERI (Visual-Empirical Region of Influence) technique is used as a method of pattern recognition to classify the solvents and mixtures and to distinguish them from water vapor. In many cases, the response of a given composite sensing film to a binary mixture deviates significantly from the sum of the responses to the isolated vapor components at the same concentrations. While these nonlinearities pose significant difficulty for (primarily) linear methods such as principal components analysis, VERI handles both linear and nonlinear data with equal ease. In the present study the maximum speciation accuracy is achieved by an array

  11. THz frequency spectrum of protein-solvent interaction energy using a recurrence plot-based Wiener-Khinchin method.

    Science.gov (United States)

    Karain, Wael

    2016-10-01

    The dynamics of a protein and the water surrounding it are coupled via nonbonded energy interactions. This coupling can exhibit a complex, nonlinear, and nonstationary nature. The THz frequency spectrum for this interaction energy characterizes both the vibration spectrum of the water hydrogen bond network, and the frequency range of large amplitude modes of proteins. We use a Recurrence Plot based Wiener-Khinchin method RPWK to calculate this spectrum, and the results are compared to those determined using the classical auto-covariance-based Wiener-Khinchin method WK. The frequency spectra for the total nonbonded interaction energy extracted from molecular dynamics simulations between the β-Lactamase Inhibitory Protein BLIP, and water molecules within a 10 Å distance from the protein surface, are calculated at 150, 200, 250, and 310 K, respectively. Similar calculations are also performed for the nonbonded interaction energy between the residues 49ASP, 53TYR, and 142PHE in BLIP, with water molecules within 10 Å from each residue respectively at 150, 200, 250, and 310 K. A comparison of the results shows that RPWK performs better than WK, and is able to detect some frequency data points that WK fails to detect. This points to the importance of using methods capable of taking the complex nature of the protein-solvent energy landscape into consideration, and not to rely on standard linear methods. In general, RPWK can be a valuable addition to the analysis tools for protein molecular dynamics simulations. Proteins 2016; 84:1549-1557. © 2016 Wiley Periodicals, Inc.

  12. Solution phase synthesis of aluminum-doped silicon nanoparticles via room-temperature, solvent based chemical reduction of silicon tetrachloride

    Science.gov (United States)

    Mowbray, Andrew James

    We present a method of wet chemical synthesis of aluminum-doped silicon nanoparticles (Al-doped Si NPs), encompassing the solution-phase co-reduction of silicon tetrachloride (SiCl4) and aluminum chloride (AlCl 3) by sodium naphthalide (Na[NAP]) in 1,2-dimethoxyethane (DME). The development of this method was inspired by the work of Baldwin et al. at the University of California, Davis, and was adapted for our research through some noteworthy procedural modifications. Centrifugation and solvent-based extraction techniques were used throughout various stages of the synthesis procedure to achieve efficient and well-controlled separation of the Si NP product from the reaction media. In addition, the development of a non-aqueous, formamide-based wash solution facilitated simultaneous removal of the NaCl byproduct and Si NP surface passivation via attachment of 1-octanol to the particle surface. As synthesized, the Si NPs were typically 3-15 nm in diameter, and were mainly amorphous, as opposed to crystalline, as concluded from SAED and XRD diffraction pattern analysis. Aluminum doping at various concentrations was accomplished via the inclusion of aluminum chloride (AlCl3); which was in small quantities dissolved into the synthesis solution to be reduced alongside the SiCl4 precursor. The introduction of Al into the chemically-reduced Si NP precipitate was not found to adversely affect the formation of the Si NPs, but was found to influence aspects such as particle stability and dispersibility throughout various stages of the procedure. Analytical techniques including transmission electron microscopy (TEM), FTIR spectroscopy, and ICP-optical emission spectroscopy were used to comprehensively characterize the product NPs. These methods confirm both the presence of Al and surface-bound 1-octanol in the newly formed Si NPs.

  13. Molecular Thermodynamic Modeling of Mixed Solvent Solubility

    DEFF Research Database (Denmark)

    Ellegaard, Martin Dela; Abildskov, Jens; O’Connell, John P.

    2010-01-01

    A method based on statistical mechanical fluctuation solution theory for composition derivatives of activity coefficients is employed for estimating dilute solubilities of 11 solid pharmaceutical solutes in nearly 70 mixed aqueous and nonaqueous solvent systems. The solvent mixtures range from...... nearly ideal to strongly nonideal. The database covers a temperature range from 293 to 323 K. Comparisons with available data and other existing solubility methods show that the method successfully describes a variety of observed mixed solvent solubility behaviors using solute−solvent parameters from...... global regression of ternary data as well as predictions based on pure solvent solubilities with an average error of about 10% on mole fractions....

  14. Solvent-resistant organic transistors and thermally stable organic photovoltaics based on cross-linkable conjugated polymers

    KAUST Repository

    Kim, Hyeongjun

    2012-01-10

    Conjugated polymers, in general, are unstable when exposed to air, solvent, or thermal treatment, and these challenges limit their practical applications. Therefore, it is of great importance to develop new materials or methodologies that can enable organic electronics with air stability, solvent resistance, and thermal stability. Herein, we have developed a simple but powerful approach to achieve solvent-resistant and thermally stable organic electronic devices with a remarkably improved air stability, by introducing an azide cross-linkable group into a conjugated polymer. To demonstrate this concept, we have synthesized polythiophene with azide groups attached to end of the alkyl chain (P3HT-azide). Photo-cross-linking of P3HT-azide copolymers dramatically improves the solvent resistance of the active layer without disrupting the molecular ordering and charge transport. This is the first demonstration of solvent-resistant organic transistors. Furthermore, the bulk-heterojunction organic photovoltaics (BHJ OPVs) containing P3HT-azide copolymers show an average efficiency higher than 3.3% after 40 h annealing at an elevated temperature of 150 °C, which represents one of the most thermally stable OPV devices reported to date. This enhanced stability is due to an in situ compatibilizer that forms at the P3HT/PCBM interface and suppresses macrophase separation. Our approach paves a way toward organic electronics with robust and stable operations. © 2011 American Chemical Society.

  15. Nanostructured alkyl carboxylic acid-based restricted access solvents: Application to the combined microextraction and cleanup of polycyclic aromatic hydrocarbons in mosses.

    Science.gov (United States)

    Caballero-Casero, N; Çabuk, H; Martínez-Sagarra, G; Devesa, J A; Rubio, S

    2015-08-26

    Alkyl carboxylic acid-based nanostructured solvents, synthesized in mixtures of tetrahydrofuran (THF) and water through self-assembly and coacervation, were proved to behave as restricted access liquids. Both physical and chemical mechanisms were found responsible for exclusion of macromolecules such as proteins and polysaccharides. The potential of these solvents for extracting small molecules from complex solid samples, without interference from large biomolecules, was here evaluated. For this purpose, they were applied to the extraction of 14 priority polycyclic aromatic hydrocarbons (PAHs) from mosses prior to their separation by liquid chromatography and fluorescence detection (LC-FLD). Sample treatment involved the vortex shaking of 200 mg of moss with 200 μL of decanoic acid-based solvent for 5 min, subsequent centrifugation for 8 min and analysis of the extract by LC-FLD using external calibration. Proteins precipitated during extraction because of both the decrease of the dielectric constant of the solution caused by THF and the formation of macromolecular complexes with decanoic acid. Polysaccharides were not solubilized in the aqueous cavities of the solvent because of their size exclusion. In-house method validation was performed according to the recommendations of the European Commission Decision 202/657/EC. Method detection and quantification limits for the different PAHs were in the ranges 0.04-0.24 and 0.14-0.80 μg kg(-1), respectively. The method was applied to the determination of different moss species collected in both polluted and unpolluted sites in the South of Spain. Recoveries were within the range 71-110%. The results obtained show that solvents with restricted access properties have the potential to expand the scope of application of restricted access materials to areas other than biological fluids because of their suitability to combine analyte isolation and sample cleanup of solid samples in a single step.

  16. Evaluation of Mercury in Environmental Samples by a Supramolecular SolventBased Dispersive LiquidLiquid Microextraction Method Before Analysis by a Cold Vapor Generation Technique.

    Science.gov (United States)

    Ali, Jamshed; Tuzen, Mustafa; Kazi, Tasneem G

    2017-02-01

    Supramolecular solvent–based dispersive liquid–liquid microextraction was used as a preconcentration method for the determination of trace levels of Hg. This simple method accurately measured oxidized HgII content in claystone and sandstone samples obtained from the Thar Coalfield in Pakistan. Cold vapor atomic absorption spectrometry was used as the detection technique because it is reliable and accurate. The HgII in acidic media forms a complex with dithizone (DTz) in the presence of supramolecular solvent (tetrahydrofuran and 1-undecanol), forming reverse micelles. Formation of the Hg-DTz complex was achieved to increase the interactions with the supramolecular solvent phase at pH 2.5 under the optimized experimental conditions. After addition of the supramolecular solvent to the aqueous solution, the micelles were uniformly mixed using a vortex mixer. The cloudy solution was centrifuged, and the Hg-DTz complex was extracted into the supramolecular solvent phase. Under optimized experimental conditions, the LOD and enrichment factor were found to be 5.61 ng/L and 77.8, respectively. Accuracy of the developed method was checked with Certified Reference Materials. The developed method was successfully applied for the determination of HgII in claystone and sandstone samples from the Block VII and Block VIII areas of the Thar Coalfield on the basis of depth.

  17. Spectroscopic, solvent influence and thermal studies of ternary copper(II) complexes of diester and dinitrogen base ligands.

    Science.gov (United States)

    Emara, Adel A A; Abu-Hussein, Azza A A; Taha, Ahmed A; Mahmoud, Nelly H

    2010-10-15

    New mixed-ligand copper(II) complexes containing the bidentate dinitrogen ligands [N,N,N',N'-tetramethylethylenediamine (tmen), 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen)] and the bidentate dioxygen ligands [diethylmalonate (DEM), ethylacetoacetate (EAA) and ethylbenzoylacetate (EBA)] were prepared. The complexes were characterized by elemental analysis, infrared, mass and ESR spectral data, magnetic and molar conductance measurements and thermal gravimetric analysis. From the investigation, the geometries of the complexes are square planar for perchlorate complexes and a square pyramid or octahedral for the nitrate complexes. Solvatochromic behavior of the Cu(II) complexes indicates strong solvatochromism of their solutions in polar and non-polar solvents. The observed solvatochromism is due to the solute-solvent interaction between the chelate cation and the solvent molecules.

  18. Magnetic graphene oxide modified with choline chloride-based deep eutectic solvent for the solid-phase extraction of protein.

    Science.gov (United States)

    Huang, Yanhua; Wang, Yuzhi; Pan, Qi; Wang, Ying; Ding, Xueqin; Xu, Kaijia; Li, Na; Wen, Qian

    2015-06-02

    Four kinds of green deep eutectic solvents (DESs) based on choline chloride (ChCl) have been synthesized and coated on the surface of magnetic graphene oxide (Fe3O4@GO) to form Fe3O4@GO-DES for the magnetic solid-phase extraction of protein. X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FESEM) and thermal gravimetric analysis (TGA) were employed to characterize Fe3O4@GO-DES, and the results indicated the successful preparation of Fe3O4@GO-DES. The UV-vis spectrophotometer was used to measure the concentration of protein after extraction. Single factor experiments proved that the extraction amount was influenced by the types of DESs, solution temperature, solution ionic strength, extraction time, protein concentration and the amount of Fe3O4@GO-DES. Comparison of Fe3O4@GO and Fe3O4@GO-DES was carried out by extracting bovine serum albumin, ovalbumin, bovine hemoglobin and lysozyme. The experimental results showed that the proposed Fe3O4@GO-DES performs better than Fe3O4@GO in the extraction of acidic protein. Desorption of protein was carried out by eluting the solid extractant with 0.005 mol L(-1) Na2HPO4 contained 1 mol L(-1) NaCl. The obtained elution efficiency was about 90.9%. Attributed to the convenient magnetic separation, the solid extractant could be easily recycled.

  19. Infrared and vibrational CD spectra of partially solvated alpha-helices: DFT-based simulations with explicit solvent.

    Science.gov (United States)

    Turner, David R; Kubelka, Jan

    2007-02-22

    Theoretical simulations are used to investigate the effects of aqueous solvent on the vibrational spectra of model alpha-helices, which are only partly exposed to solvent to mimic alpha-helices in proteins. Infrared absorption (IR) and vibrational circular dichroism (VCD) amide I' spectra for 15-amide alanine alpha-helices are simulated using density functional theory (DFT) calculations combined with the property transfer method. The solvent is modeled by explicit water molecules hydrogen bonded to the solvated amide groups. Simulated spectra for two partially solvated model alpha-helices, one corresponding to a more exposed and the other to a more buried structure, are compared to the fully solvated and unsolvated (gas phase) simulations. The dependence of the amide I spectra on the orientation of the partially solvated helix with respect to the solvent and effects of solvation on the amide I' of 13C isotopically substituted alpha-helices are also investigated. The partial exposure to solvent causes significant broadening of the amide I' bands due to differences in the vibrational frequencies of the explicitly solvated and unsolvated amide groups. The different degree of partial solvation is reflected primarily in the frequency shifts of the unsolvated (buried) amide group vibrations. Depending on which side of the alpha-helix is exposed to solvent, the simulated IR band-shapes exhibit significant changes, from broad and relatively featureless to distinctly split into two maxima. The simulated amide I' VCD band-shapes for the partially solvated alpha-helices parallel the broadening of the IR and exhibit more sign variation, but generally preserve the sign pattern characteristic of the alpha-helical structures and are much less dependent on the alpha-helix orientation with respect to the solvent. The simulated amide I' IR spectra for the model peptides with explicitly hydrogen-bonded water are consistent with the experimental data for small alpha-helical proteins

  20. 环保溶剂型氯丁胶的制备%Preparation of environment-friendly solvent-based neoprene adhesive

    Institute of Scientific and Technical Information of China (English)

    赵俊勇; 杨洪记; 刘文涛; 何素芹; 朱诚身

    2012-01-01

    At present,the solvent-based neoprene adhesive was still dominant in rubber-based adhesives. In order to make low-toxicity solvent-based neoprene adhesive, the better proportion of non-benzene mixed solvents for liquefying neoprene was preferred by "solubility parameter+hydrogen bond index" method,then a pre-reaction liquid between tert-butyl phenolic resin and light-MgO was made by pre-chelation reaction. Finally, a environment-friendly solvent-based neoprene adhesive with faster curing speed and 35.5% solid contents was prepared by mixing. The research results showed that the corresponding neoprene adhesive had reversely best combination property because its shear strength and peeling strength were 1.83 Mpa and 17.9 N/25 mm respectively when mass ratio of m(120* solvent oil):m(ethyl acetate):m(acetone) was 4:7:4 in mixed solvent.%目前,溶剂型氯丁胶仍在橡胶基胶粘剂中占主导地位.为制备低毒性溶剂型氯丁胶,可根据"溶度参数+氢键指数"法优选出溶解氯丁橡胶用非苯类混合溶剂的较佳配比;然后使叔丁基酚醛树脂与轻质MgO预先发生螯合反应制得预反应液,再采用混炼法制得固化速率快、固含量高达35.5%的环保溶剂型氯丁胶.研究结果表明:当混合溶剂中m(120#溶剂油):m(乙酸乙酯):m(丙酮):4:7:4时,相应氯丁胶的综合性能相对最好,其剪切强度为1.83 MPa、剥离强度为17.9 N/25 mm.

  1. Green oxidation of alkenes in ionic liquid solvent by hydrogen peroxide over high performance Fe(III) Schiff base complexes immobilized on MCM-41

    Indian Academy of Sciences (India)

    Mohammad Taghi Goldani; Ali Mohammadi; Reza Sandaroos

    2014-05-01

    A series of Fe(III) Schiff base complexes immobilized on MCM-41 were prepared and characterized by various physicochemical and spectroscopic methods. The complexes were used for oxidation of cyclohexene by 30% hydrogen peroxide in the presence and absence of ethylmethyl imidazolium chloride (EMIM) ionic liquid as solvent. The immobilized complexes proved to be effective catalysts and generally exhibited much higher catalytic performance than their homogeneous analogue. Catalytic performance of the complexes was also found to be closely related to the Schiff base ligands used. Additionally, ion liquid solvent efficiently improved all the catalytic performances. Finally, the reaction was extended to different alkenes using the heterogeneous complex 2-L4. Among all the alkenes, those containing -electron-withdrawing groups and trans-orientations exhibited lower tendency for oxidation.

  2. A toxic organic solvent-free technology for the preparation of PEGylated paclitaxel nanosuspension based on human serum albumin for effective cancer therapy

    Directory of Open Access Journals (Sweden)

    Yin TJ

    2015-12-01

    Full Text Available Tingjie Yin,* Lihui Dong,* Bei Cui, Lei Wang, Lifang Yin, Jianping Zhou, Meirong Huo State Key Laboratory of Natural Medicines, Department of Pharmaceutics, China Pharmaceutical University, Nanjing, People’s Republic of China *These authors contributed equally to this work Abstract: Clinically, paclitaxel (PTX is one of most commonly prescribed therapies against a wide range of solid neoplasms. Despite its success, the clinical applicability of PTX (Taxol® is severely hampered by systemic toxicities induced by Cremophor EL. While attempts to bypass the need for Cremophor EL have been developed through platforms such as Abraxane™, nab™ relies heavily on the use of organic solvents, namely, chloroform. The toxicity introduced by residual chloroform poses a potential risk to patient health. To mitigate the toxicities of toxic organic solvent-based manufacture methods, we have designed a method for the formulation of PTX nanosuspensions (PTX-PEG [polyethylene glycol]-HSA [human serum albumin] that eliminates the dependence on toxic organic solvents. Coined the solid-dispersion technology, this technique permits the dispersion of PTX into PEG skeleton without the use of organic solvents or Cremophor EL as a solubilizer. Once the PTX-PEG dispersion is complete, the dispersion can be formulated with HSA into nanosuspensions suitable for intravenous administration. Additionally, the incorporation of PEG permits the prolonged circulation through the steric stabilization effect. Finally, HSA-mediated targeting permits active receptor-mediated endocytosis for enhanced tumor uptake and reduced side effects. By eliminating the need for both Cremophor EL and organic solvents while simultaneously increasing antitumor efficacy, this method provides a superior alternative to currently accepted methods for PTX delivery. Keywords: human serum albumin, nanosuspension, paclitaxel, polyethylene glycol, solid-dispersion technology

  3. Universal solvation model based on solute electron density and on a continuum model of the solvent defined by the bulk dielectric constant and atomic surface tensions.

    Science.gov (United States)

    Marenich, Aleksandr V; Cramer, Christopher J; Truhlar, Donald G

    2009-05-07

    We present a new continuum solvation model based on the quantum mechanical charge density of a solute molecule interacting with a continuum description of the solvent. The model is called SMD, where the "D" stands for "density" to denote that the full solute electron density is used without defining partial atomic charges. "Continuum" denotes that the solvent is not represented explicitly but rather as a dielectric medium with surface tension at the solute-solvent boundary. SMD is a universal solvation model, where "universal" denotes its applicability to any charged or uncharged solute in any solvent or liquid medium for which a few key descriptors are known (in particular, dielectric constant, refractive index, bulk surface tension, and acidity and basicity parameters). The model separates the observable solvation free energy into two main components. The first component is the bulk electrostatic contribution arising from a self-consistent reaction field treatment that involves the solution of the nonhomogeneous Poisson equation for electrostatics in terms of the integral-equation-formalism polarizable continuum model (IEF-PCM). The cavities for the bulk electrostatic calculation are defined by superpositions of nuclear-centered spheres. The second component is called the cavity-dispersion-solvent-structure term and is the contribution arising from short-range interactions between the solute and solvent molecules in the first solvation shell. This contribution is a sum of terms that are proportional (with geometry-dependent proportionality constants called atomic surface tensions) to the solvent-accessible surface areas of the individual atoms of the solute. The SMD model has been parametrized with a training set of 2821 solvation data including 112 aqueous ionic solvation free energies, 220 solvation free energies for 166 ions in acetonitrile, methanol, and dimethyl sulfoxide, 2346 solvation free energies for 318 neutral solutes in 91 solvents (90 nonaqueous

  4. Effects of residual water on microtensile bond strength of one-bottle dentin adhesive systems with different solvent bases

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-xing; HUANG Cui; ZHENG Tie-li; WANG Sa; CHENG Xiang-rong

    2005-01-01

    Background The wet-bonding technique is recommended for the one-bottle dentin adhesive systems, but the moisture concept varies widely among the instructions of manufacturers as well as among investigators. The aim of this study was to evaluate the effects of different dentin surface moisture on the microtensile bond strength(s) of an ethanol/water-based adhesive system and an acetone-based system to dentin. Methods Forty intact human premolars extracted for orthodontic reasons were used. Superficial occlusal flat dentin surfaces of these premolars were exposed, finished with wet 600-grit silicon carbide paper. Under four wet and dry conditions (overwet, blot dry, one-second dry and desiccated), resin composite was bonded to dentin by using Single Bond (SB) or Prime & Bond NT (PB) according to the manufacturers' instructions. The teeth were longitudinally sectioned in the "x" and "y" directions to obtain bonded beams with a cross-sectional area of 0.81 mm2 with a slow-speed diamond saw. The bonded specimens were tested in tension at a crosshead speed of 1 mm/min until failure of the bonds. Failure modes were observed with a scanning electron microscope. The mean bond strengths were analyzed by one-way ANOVA and Turkey's test. Results The bond strength of the overwet/SB, blot dry/SB, one-second dry/SB and desiccated/SB groups was 10.87 Mpa, 22.47 Mpa, 24.91 Mpa and 12.99 Mpa, respectively. The bond strength of the overwet/PB, blot dry/PB, one-second dry/PB and desiccated/PB groups was 10.02 Mpa, 20.67 Mpa, 21.82 Mpa and 10.09 Mpa, respectively. For both SB and PB, the blot dry group and one-second dry group revealed significantly higher bond strengths than the overwet and desiccated groups (P<0.05). Conclusions In order to achieve the highest bond strength to dentin, keeping the dentin surface in an appropriately moist condition is critical for the one-bottle dentin adhesive systems with ethanol/water or acetone solvent.

  5. Standard Practice for Preparing Aircraft Cleaning Compounds, Liquid-Type, Temperature-Sensitive, or Solvent-Based, for Storage Stability Testing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This practice covers the determination of the stability in storage of liquid enzyme-based, terpene-based, and solvent-based chemical cleaning compounds used to clean the exterior surfaces of aircraft. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  6. Performance evaluation of titanium dioxide based dye-sensitized solar cells under the influence of anodization steps, nanotube length and ionic liquid-free redox electrolyte solvents

    Science.gov (United States)

    Cheong, Y. L.; Beh, K. P.; Yam, F. K.; Hassan, Z.

    2016-06-01

    In this work, highly ordered titanium dioxide (TiO2) nanotube (NT) arrays were synthesized on titanium foil using electrochemical anodization method. The morphological aspects of the nanotubes based on different anodization duration and number of anodization steps (maximum two) have been investigated. The nanotube arrays subsequently used as photoanode in a dye-sensitized solar cell (DSSC) assembly. The studies on the effects of different solvents for triiodide/iodide redox electrolyte and NT length towards the performance of DSSC were conducted. It is known that electrolyte solvent can significantly affect the photovoltaic conversion efficiency. It is noteworthy that longer NT length tends to yield higher efficiency due to better dye adsorption. However, when the NTs exceeded certain length the efficiency decreases instead. Meanwhile, a comparison of DSSC performance based on number of anodization steps on titanium was performed. Highly ordered NT arrays could be obtained using two-steps anodization, which proved to have positive effects on the DSSC performance. The highest photovoltaic conversion efficiency in this work is 2.04%, achieved by two-step anodization. The corresponding average nanotubes length was ˜18 μm, with acetonitrile (ACN) as the redox electrolyte solvent.

  7. Mdea Based Solvents Used At the Lacq Processing Plant Utilisation de solvants à base de MDEA à l'usine de Lacq

    Directory of Open Access Journals (Sweden)

    Elgue J.

    2006-11-01

    Full Text Available The use of MDEA-based solvents has allowed the processing scheme of the sour natural gases treated at the Lacq plant to be modified, leading to substantial savings in operating costs. Compared to the well known SNPA-DEA process, the new MDEA-based solvents meet the same performance requirements as regards H2S and CO2 removal, but are far more economic in terms of energy consumption. MDEA is used to selectively remove H2S from the gas, while activated MDEA is used when total acid gas removal is necessary. The adequate activator has been selected from among a series of products, according to the actual plant specificity. Optimization of the process has included the selection of the proper contacting device : for this mass transfer enhanced by chemical first order reaction, structured packings have proven to be more efficient than trays. L'utilisation de solvants à base de MDEA a permis de modifier le schéma de désulfuration du gaz de Lacq et de réaliser ainsi de substantielles économies de traitement. Les procédés à base des nouveaux solvants permettent d'atteindre les mêmes performances d'élimination de H2S et du CO2, avec une consommation d'énergie très inférieure à celle du désormais classique procédé SNPA-DEA. La MDEA est utilisée pour l'enlèvement sélectif de l'H2S, alors que la MDEA activée permet l'élimination complète des composés acides. L'activateur le mieux adapté aux conditions de fonctionnement spécifiques des unités de Lacq a été sélectionné parmi une série de produits. Dans le cadre de l'optimisation des unités, les internes du contacteur gaz/liquide ont été changés : les garnissages structurés ont confirmé leur efficacité supérieure à celle des plateaux à clapets pour ce transfert de matière avec réaction chimique.

  8. Substituent and Solvent Effects on Excited State Charge Transfer Behavior of Highly Fluorescent Dyes Containing Thiophenylimidazole-Based Aldehydes

    Science.gov (United States)

    Santos, Javier; Bu, Xiu R.; Mintz, Eric A.

    2001-01-01

    The excited state charge transfer for a series of highly fluorescent dyes containing thiophenylimidazole moiety was investigated. These systems follow the Twisted Intramolecular Charge Transfer (TICT) model. Dual fluorescence was observed for each substituted dye. X-ray structures analysis reveals a twisted ground state geometry for the donor substituted aryl on the 4 and 5 position at the imidazole ring. The excited state charge transfer was modeled by a linear solvation energy relationship using Taft's pi and Dimroth's E(sub T)(30) as solvent parameters. There is linear relation between the energy of the fluorescence transition and solvent polarity. The degree of stabilization of the excited state charge transfer was found to be consistent with the intramolecular molecular charge transfer. Excited dipole moment was studied by utilizing the solvatochromic shift method.

  9. Impact of heating rate and solvent on Ni-based catalysts prepared by solution combustion method for syngas methanation

    Directory of Open Access Journals (Sweden)

    Zeng Yan

    2014-12-01

    Full Text Available Ni-Al2O3 catalysts prepared by solution combustion method for syngas methanation were enhanced by employing various heating rate and different solvent. The catalytic properties were tested in syngas methanation. The result indicates that both of heating rate and solvent remarkably affect Ni particle size, which is a key factor to the catalytic activity of Ni-Al2O3 catalysts for syngas methanation. Moreover, the relationship between Ni particle size and the production rate of methane per unit mass was correlated. The optimal Ni-Al2O3 catalyst prepared in ethanol at 2°C/min, achieves a maximum production rate of methane at the mean size of 20.8 nm.

  10. Enzymatic Synthesis of Glucose-Based Fatty Acid Esters in Bisolvent Systems Containing Ionic Liquids or Deep Eutectic Solvents

    Directory of Open Access Journals (Sweden)

    Kai-Hua Zhao

    2016-09-01

    Full Text Available Sugar fatty acid esters (SFAEs are biocompatible nonionic surfactants with broad applications in food, cosmetic, and pharmaceutical industries. They can be synthesized enzymatically with many advantages over their chemical synthesis. In this study, SFAE synthesis was investigated by using two reactions: (1 transesterification of glucose with fatty acid vinyl esters and (2 esterification of methyl glucoside with fatty acids, catalyzed by Lipozyme TLIM and Novozym 435 respectively. Fourteen ionic liquids (ILs and 14 deep eutectic solvents (DESs were screened as solvents, and the bisolvent system composed of 1-hexyl-3-methylimidazolium trifluoromethylsulfonate ([HMIm][TfO] and 2-methyl-2-butanol (2M2B was the best for both reactions, yielding optimal productivities (769.6 and 397.5 µmol/h/g, respectively which are superior to those reported in the literature. Impacts of different reaction conditions were studied for both reactions. Response surface methodology (RSM was employed to optimize the transesterification reaction. Results also demonstrated that as co-substrate, methyl glucoside yielded higher conversions than glucose, and that conversions increased with an increase in the chain length of the fatty acid moieties. DESs were poor solvents for the above reactions presumably due to their high viscosity and high polarity.

  11. Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations

    Directory of Open Access Journals (Sweden)

    Serena Traboni

    2016-12-01

    Full Text Available tert-Butyldimethylsilyl (TBDMS and tert-butyldiphenylsilyl (TBDPS are alcohol protecting groups widely employed in organic synthesis in view of their compatibility with a wide range of conditions. Their regioselective installation on polyols generally requires lengthy reactions and the use of high boiling solvents. In the first part of this paper we demonstrate that regioselective silylation of sugar polyols can be conducted in short times with the requisite silyl chloride and a very limited excess of pyridine (2–3 equivalents. Under these conditions, that can be regarded as solvent-free conditions in view of the insolubility of the polyol substrates, the reactions are faster than in most examples reported in the literature, and can even be further accelerated with a catalytic amount of tetrabutylammonium bromide (TBAB. The strategy proved also useful for either the selective TBDMS protection of secondary alcohols or the fast per-O-trimethylsilylation of saccharide polyols. In the second part of the paper the scope of the silylation approach was significantly extended with the development of unprecedented “one-pot” and “solvent-free” sequences allowing the regioselective silylation/alkylation (or the reverse sequence of saccharide polyols in short times. The developed methodologies represent a very useful and experimentally simple tool for the straightforward access to saccharide building-blocks useful in organic synthesis.

  12. Solvent Effects on the Electrochemical Behavior of TAPD-Based Redox-Responsive Probes for Cadmium(II

    Directory of Open Access Journals (Sweden)

    Rihab Sahli

    2014-01-01

    Full Text Available Two tetralkylated phenylenediamines (TAPD 1 and 2 have been prepared by reductive alkylation of para-dimethylaminoaniline with furfural or thiophene 2-carboxaldehyde, respectively. Their chelation ability has been evaluated as electrochemical guest-responsive chemosensors for Cd(II in acetonitrile (ACN, dimethylformamide (DMF, propylene carbonate (PC, and nitromethane (NM. The voltamperometric studies showed that these compounds are able to bind the Cd(II cation with strong affinities except in DMF. The redox features of the chemosensors changed drastically when they are bounded to Cd(II to undergo important anodic potential peak shifts comprised between ca. 500 and ca. 900 mV depending on the solvent. The addition of ∼4–10% molar triflic acid (TfOH was found to be necessary to achieve rapidly the cation chelation which is slow without the acid. The electrochemical investigations suggested the formation of 1 : 2 stoichiometry complexes [Cd(L2]2+. The results are discussed in terms of solvent effects as a competitive electron donating ligand to the cation. The reaction coupling efficiency (RCE values were determined and were also found to be solvent-dependent.

  13. Improving the Performances of Random Copolymer Based Organic Solar Cells by Adjusting the Film Features of Active Layers Using Mixed Solvents

    Directory of Open Access Journals (Sweden)

    Xiangwei Zhu

    2015-12-01

    Full Text Available A novel random copolymer based on donor–acceptor type polymers containing benzodithiophene and dithienosilole as donors and benzothiazole and diketopyrrolopyrrole as acceptors was designed and synthesized by Stille copolymerization, and their optical, electrochemical, charge transport, and photovoltaic properties were investigated. This copolymer with high molecular weight exhibited broad and strong absorption covering the spectra range from 500 to 800 nm with absorption maxima at around 750 nm, which would be very conducive to obtaining large short-circuits current densities. Unlike the general approach using single solvent to prepare the active layer film, mixed solvents were introduced to change the film feature and improve the morphology of the active layer, which lead to a significant improvement of the power conversion efficiency. These results indicate that constructing random copolymer with multiple donor and acceptor monomers and choosing proper mixed solvents to change the characteristics of the film is a very promising way for manufacturing organic solar cells with large current density and high power conversion efficiency.

  14. Solvents in novolak synthesis

    Science.gov (United States)

    Sobodacha, Chet J.; Lynch, Thomas J.; Durham, Dana L.; Paradis, Valerie R.

    1993-09-01

    Novolac resins may be prepared with or without a solvent present. We have found that solvent power greatly affects the properties of the finished resin and thus gives the resist chemist another variable with which to `fine-tune' resist properties. Using designed experiments, we investigated the effect of solvent power, as measured by Hansen's Solubility Parameters, of a number of solvents and solvent mixtures on the final properties of the novolac resin. We found that the relative molecular weight (RMW) and dissolution rate of a novolac resin can be varied by selection of a solvent or solvent mixture with the appropriate polarity and hydrogen- bonding characteristics. The solvent polarity and hydrogen-bonding characteristics may affect the stability of the cresol/formaldehyde transition state, thus causing the observed changes in RMW and dissolution rate.

  15. The effect of macromolecular crowding on the electrostatic component of barnase-barstar binding: a computational, implicit solvent-based study.

    Directory of Open Access Journals (Sweden)

    Helena W Qi

    Full Text Available Macromolecular crowding within the cell can impact both protein folding and binding. Earlier models of cellular crowding focused on the excluded volume, entropic effect of crowding agents, which generally favors compact protein states. Recently, other effects of crowding have been explored, including enthalpically-related crowder-protein interactions and changes in solvation properties. In this work, we explore the effects of macromolecular crowding on the electrostatic desolvation and solvent-screened interaction components of protein-protein binding. Our simple model enables us to focus exclusively on the electrostatic effects of water depletion on protein binding due to crowding, providing us with the ability to systematically analyze and quantify these potentially intuitive effects. We use the barnase-barstar complex as a model system and randomly placed, uncharged spheres within implicit solvent to model crowding in an aqueous environment. On average, we find that the desolvation free energy penalties incurred by partners upon binding are lowered in a crowded environment and solvent-screened interactions are amplified. At a constant crowder density (fraction of total available volume occupied by crowders, this effect generally increases as the radius of model crowders decreases, but the strength and nature of this trend can depend on the water probe radius used to generate the molecular surface in the continuum model. In general, there is huge variation in desolvation penalties as a function of the random crowder positions. Results with explicit model crowders can be qualitatively similar to those using a lowered "effective" solvent dielectric to account for crowding, although the "best" effective dielectric constant will likely depend on multiple system properties. Taken together, this work systematically demonstrates, quantifies, and analyzes qualitative intuition-based insights into the effects of water depletion due to crowding on the

  16. Identifying native-like protein structures with scoring functions based on all-atom ECEPP force fields, implicit solvent models and structure relaxation.

    Science.gov (United States)

    Arnautova, Yelena A; Vorobjev, Yury N; Vila, Jorge A; Scheraga, Harold A

    2009-10-01

    Availability of energy functions which can discriminate native-like from non-native protein conformations is crucial for theoretical protein structure prediction and refinement of low-resolution protein models. This article reports the results of benchmark tests for scoring functions based on two all-atom ECEPP force fields, that is, ECEPP/3 and ECEPP05, and two implicit solvent models for a large set of protein decoys. The following three scoring functions are considered: (i) ECEPP05 plus a solvent-accessible surface area model with the parameters optimized with a set of protein decoys (ECEPP05/SA); (ii) ECEPP/3 plus the solvent-accessible surface area model of Ooi et al. (Proc Natl Acad Sci USA 1987;84:3086-3090) (ECEPP3/OONS); and (iii) ECEPP05 plus an implicit solvent model based on a solution of the Poisson equation with an optimized Fast Adaptive Multigrid Boundary Element (FAMBEpH) method (ECEPP05/FAMBEpH). Short Monte Carlo-with-Minimization (MCM) simulations, following local energy minimization, are used as a scoring method with ECEPP05/SA and ECEPP3/OONS potentials, whereas energy calculation is used with ECEPP05/FAMBEpH. The performance of each scoring function is evaluated by examining its ability to distinguish between native-like and non-native protein structures. The results of the tests show that the new ECEPP05/SA scoring function represents a significant improvement over the earlier ECEPP3/OONS version of the force field. Thus, it is able to rank native-like structures with C(alpha) root-mean-square-deviations below 3.5 A as lowest-energy conformations for 76% and within the top 10 for 87% of the proteins tested, compared with 69 and 80%, respectively, for ECEPP3/OONS. The use of the FAMBEpH solvation model, which provides a more accurate description of the protein-solvent interactions, improves the discriminative ability of the scoring function to 89%. All failed tests in which the native-like structures cannot be discriminated as those with low

  17. Accelerated solvent extraction for GC-based tobacco fingerprinting and its comparison with simultaneous distillation and extraction.

    Science.gov (United States)

    Li, Yong; Pang, Tao; Guo, Ziming; Li, Yanli; Wang, Xiaolin; Deng, Jianhua; Zhong, Kejun; Lu, Xin; Xu, Guowang

    2010-04-15

    An accelerated solvent extraction (ASE) procedure has been developed as a pretreatment method for chemical fingerprinting of volatile and semi-volatile components in cut tobacco. The ASE extraction conditions including temperature, operation pressure and extraction cycles were optimized to maximize extraction yield. The method was validated with repeatability, recovery and linearity. Compared with simultaneous distillation extraction (SDE), ASE provides higher extraction yields, less extraction time, lower solvent consumption and less labor time, and is more suitable for tobacco sample preparation. A typical ASE extract was analyzed by gas chromatography/time-of-flight mass spectrometry (GC-TOFMS). A total of 305 components with signal-to-noise ratio higher than 100 were tentatively identified by NIST05 and Wiley database. Finally, 36 cigarette samples from six cigarette brands were analyzed using the developed chemical fingerprinting method. Partial least squares-discriminant analysis shows good discrimination of different cigarette brands. The results indicate that ASE method can serve as high-throughput sample preparation technique for cigarette chemical fingerprint analysis.

  18. Designing Solvent Exchange-Induced In Situ Forming Gel from Aqueous Insoluble Polymers as Matrix Base for Periodontitis Treatment.

    Science.gov (United States)

    Srichan, Tharatree; Phaechamud, Thawatchai

    2017-01-01

    An in situ forming gel is a dosage form which is promised for site-specific therapy such as periodontal pocket of periodontitis treatment. Ethylcellulose, bleached shellac, and Eudragit RS were applied in this study as a polymeric matrix for in situ forming gel employing N-methyl pyrrolidone (NMP) as solvent. Solutions comprising ethylcellulose, bleached shellac, and Eudragit RS in NMP were evaluated for viscosity, rheology, and rate of water penetration. Ease of administration by injection was determined as the force required to expel polymeric solutions through a needle using texture analyzer. In vitro gel formation and in vitro gel degradation were conducted after injection into phosphate buffer solution pH 6.8. Ethylcellulose, bleached shellac, and Eudragit RS could form the in situ gel, in vitro. Gel viscosity and pH value depended on percentage amount of the polymer, whereas the water diffusion at early period likely relied on types of polymer. Furthermore, the solutions containing higher polymer concentration exhibited the lower degree of degradation. All the preparations were acceptable as injectable dosage forms because the applied force was lower than 50 N. All of them inhibited Staphylococcus aureus, Escherichia coli, Candida albicans, Streptococcus mutans, and Porphyrommonas gingivalis growth owing to antimicrobial activity of NMP which exhibited a potential use for periodontitis treatment. Moreover, the developed systems presented as the solvent exchange induced in situ forming gel and showed capability to be incorporated with the suitable antimicrobial active compounds for periodontitis treatment which should be further studied.

  19. Solvent abuse: a review.

    Science.gov (United States)

    Barnes, G E

    1979-01-01

    The literature on solvent abuse is reviewed. Methods of use, symptoms of use, and effects of long-term solvent abuse are discussed. Several surveys on solvent use are summarized. The highest prevalence of solvent abuse seems to occur in native peoples undergoing periods of cultural change. Environmental conditions which are postulated as leading to psychological vulnerability and solvent abuse include: low social assets, parental drug use, peer and sibling influence, and acculturative stress. Solvent abuse seems to provide a pharmacological way out of a stressful environment for people who feel helpless to improve their situation in other ways. Methods of intervention that have been proposed for dealing with solvent abuse are discussed. Methods of intervention thus far employed generally have not been evaluated in any systematic fashion. Suggestions for future research are provided.

  20. Synthesis of (E-2-Styrylchromones and Flavones by Base-Catalyzed Cyclodehydration of the Appropriate β-Diketones Using Water as Solvent

    Directory of Open Access Journals (Sweden)

    Joana Pinto

    2015-06-01

    Full Text Available A low cost, safe, clean and environmentally benign base-catalyzed cyclodehydration of appropriate β-diketones affording (E-2-styrylchromones and flavones in good yields is disclosed. Water was used as solvent and the reactions were heated using classical and microwave heating methods, under open and closed vessel conditions. β-Diketones having electron-donating and withdrawing substituents were used to evaluate the reaction scope. The reaction products were isolated in high purity by simple filtration and recrystallization from ethanol, when using 800 mg of the starting diketone under classical reflux heating conditions.

  1. EFFECTS OF SOLVENT, BASE, AND TEMPERATURE IN THE OPTIMISATION OF A NEW CATALYTIC SYSTEM FOR SONOGASHIRA CROSS-COUPLING USING NCP PINCER PALLADACYCLE

    Directory of Open Access Journals (Sweden)

    Diego S. Rosa

    2015-05-01

    Full Text Available The optimisation of a new catalyst system using NCP pincer palladacycle 1 was investigated using the experimental design technique. NCP pincer palladacycle 1 was previously investigated in Suzuki-Miyaura and Heck-Mizoroki cross-couplings and found to be a highly efficient catalyst precursor. In this study, the effects of the type of base (K3PO4 or DABCO, solvent (DMF or dioxane and reaction temperature (130 or 150 ºC in the second step on the reactional yield in Sonogashira cross-coupling were assessed using the two-factor design. The results showed that temperature is statistically significant in relation to the reaction yield.

  2. A facile, green, one-pot synthesis of amidoalkyl naphthols under solvent-free conditions catalyzed by a carbon-based solid acid

    Institute of Scientific and Technical Information of China (English)

    Abolghasem Davoodnia; Rahil Mahjoobin; Niloofar Tavakoli-Hoseini

    2014-01-01

    An efficient, environmentally friendly procedure for the synthesis of amidoalkyl naphthols through the one-pot, three-component reaction of β-naphthol, aryl aldehydes, and acetamide in the presence of a carbon-based solid acid under thermal solvent-free conditions is described. The beneficial fea-tures of this new synthetic approach include short reaction time, high yields, clean reaction profiles, and a simple work-up procedure. Furthermore, the catalyst can be readily recycled and reused four times without obvious significant loss of activity. The structure of the catalyst was confirmed by Fourier transform infrared spectroscopy, N2 adsorption/desorption analysis, and X-ray diffraction.

  3. DOE solvent handbook information sheet

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, A.A.

    1992-01-01

    Solvents and cleaners are used in the Department of Defense (DOD) and the Department of Energy-Defense Program (DOE-DP) maintenance facilities for removing wax, grease, oil, carbon, machining fluids, solder fluxes, mold releases, and other contaminants before repairing or electroplating parts. Private industry also uses cleaners and degreasers for surface preparation of various metals. Growing environmental and worker safety concerns have brought attention to these solvents and cleaners, most of which are classified as toxic. Tightening government regulations have already excluded the use of some chemicals, and restrict the use of various halogenated hydrocarbons because of their atmospheric-ozone depleting effects, as well as their cancer-related risks. As a result, a program was established to develop an efficient, easily accessible, electronic solvent utilization handbook. This is being accomplished by: (1) identifying solvents (alternatives) that are not currently restricted by government regulations for use DOE-DP facilities, and private industry, (2) evaluating their cleaning performance, (3) evaluating their corrosivity, (4) evaluating their air emissions, (5) evaluating the possibility of recycling or recovering all or portions of the alternative degreasers, (6) testing substitute solvents compatibility with non-metallic materials, (7) inputting all of the data gathered (including previous biodegradability information) into a database, and (8) developing a methodology for efficient, widespread access to the data base information system.

  4. DOE solvent handbook information sheet

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, A.A.

    1992-05-01

    Solvents and cleaners are used in the Department of Defense (DOD) and the Department of Energy-Defense Program (DOE-DP) maintenance facilities for removing wax, grease, oil, carbon, machining fluids, solder fluxes, mold releases, and other contaminants before repairing or electroplating parts. Private industry also uses cleaners and degreasers for surface preparation of various metals. Growing environmental and worker safety concerns have brought attention to these solvents and cleaners, most of which are classified as toxic. Tightening government regulations have already excluded the use of some chemicals, and restrict the use of various halogenated hydrocarbons because of their atmospheric-ozone depleting effects, as well as their cancer-related risks. As a result, a program was established to develop an efficient, easily accessible, electronic solvent utilization handbook. This is being accomplished by: (1) identifying solvents (alternatives) that are not currently restricted by government regulations for use DOE-DP facilities, and private industry, (2) evaluating their cleaning performance, (3) evaluating their corrosivity, (4) evaluating their air emissions, (5) evaluating the possibility of recycling or recovering all or portions of the alternative degreasers, (6) testing substitute solvents compatibility with non-metallic materials, (7) inputting all of the data gathered (including previous biodegradability information) into a database, and (8) developing a methodology for efficient, widespread access to the data base information system.

  5. Membrane-Based Osmotic Heat Engine with Organic Solvent for Enhanced Power Generation from Low-Grade Heat

    Energy Technology Data Exchange (ETDEWEB)

    Shaulsky, E; Boo, C; Lin, SH; Elimelech, M

    2015-05-05

    We present a hybrid osmotic heat engine (OHE) system that uses draw solutions with an organic solvent for enhanced thermal separation efficiency. The hybrid OHE system produces sustainable energy by combining pressure-retarded osmosis (PRO) as a power generation stage and membrane distillation (MD) utilizing low-grade heat as a separation stage. While previous OHE systems employed aqueous electrolyte draw solutions, using methanol as a solvent is advantageous because methanol is highly volatile and has a lower heat capacity and enthalpy of vaporization than water. Hence, the thermal separation efficiency of a draw solution with methanol would be higher than that of an aqueous draw solution. In this study, we evaluated the performance of LiCl-methanol as a potential draw solution for a PRO-MD hybrid OHE system. The membrane transport properties as well as performance with LiCl methanol draw solution were evaluated using thin-film composite (TFC) PRO membranes and compared to the results obtained with a LiCl water draw solution. Experimental PRO methanol flux and maximum projected power density of 47.1 L m(-2) h(-1) and 72.1 W m(-2), respectively, were achieved with a 3 M LiCl-methanol draw solution. The overall efficiency of the hybrid OHE system was modeled by coupling the mass and energy flows between the thermal separation (MD) and power generation (PRO) stages under conditions with and without heat recovery. The modeling results demonstrate higher ORE energy efficiency with the LiCl methanol draw solution compared to that with the LiCl water draw solution under practical operating conditions (i.e., heat recovery <90%). We discuss the implications of the results for converting low-grade heat to power.

  6. Fluorescent derivatization combined with aqueous solvent-based dispersive liquid-liquid microextraction for determination of butyrobetaine, l-carnitine and acetyl-l-carnitine in human plasma.

    Science.gov (United States)

    Chen, Yi-Ching; Tsai, Chia-Ju; Feng, Chia-Hsien

    2016-09-16

    A novel aqueous solvent-based dispersive liquid-liquid microextraction (AS-DLLME) method was combined with narrow-bore liquid chromatography and fluorescence detection for the determination of hydrophilic compounds. A remover (non-polar solvent) and extractant (aqueous solution) were introduced into the derivatization system (acetonitrile) to obtain a water-in-oil emulsion state that increased the mass transfer of analytes. As a proof of concept, three quaternary ammonium substances, including butyrobetaine, l-carnitine and acetyl-l-carnitine, were also used as analytes and determined in pharmaceuticals, personal care products, food and human plasma. The analytes were derivatized with 4-bromomethylbiphenyl for fluorescence detection and improved retention in the column. The linear response was 10-2000nM for l-carnitine and acetyl-l-carnitine with a good determination coefficient (r(2)>0.998) in the standard solution. The detection limit for l-carnitine and acetyl-l-carnitine was 4.5 fmol. The method was also successfully applied to a 1μL sample of human plasma. In the linearity calculations for determining butyrobetaine, l-carnitine and acetyl-l-carnitine in human plasma, the determination coefficients ranged from 0.996 to 0.999. Linear regression exhibited good reproducibility and a relative standard deviation better than 7.50% for the slope and 9.06% for the intercept. To characterize highly hydrophilic compounds in various samples, the proposed method provides good sensitivity for a small sample volume with a low consumption of toxic solvents.

  7. Water based on a molecular model behaves like a hard-sphere solvent for a nonpolar solute when the reference interaction site model and related theories are employed

    Science.gov (United States)

    Hayashi, Tomohiko; Oshima, Hiraku; Harano, Yuichi; Kinoshita, Masahiro

    2016-09-01

    For neutral hard-sphere solutes, we compare the reduced density profile of water around a solute g(r), solvation free energy μ, energy U, and entropy S under the isochoric condition predicted by the two theories: dielectrically consistent reference interaction site model (DRISM) and angle-dependent integral equation (ADIE) theories. A molecular model for water pertinent to each theory is adopted. The hypernetted-chain (HNC) closure is employed in the ADIE theory, and the HNC and Kovalenko-Hirata (K-H) closures are tested in the DRISM theory. We also calculate g(r), U, S, and μ of the same solute in a hard-sphere solvent whose molecular diameter and number density are set at those of water, in which case the radial-symmetric integral equation (RSIE) theory is employed. The dependences of μ, U, and S on the excluded volume and solvent-accessible surface area are analyzed using the morphometric approach (MA). The results from the ADIE theory are in by far better agreement with those from computer simulations available for g(r), U, and μ. For the DRISM theory, g(r) in the vicinity of the solute is quite high and becomes progressively higher as the solute diameter d U increases. By contrast, for the ADIE theory, it is much lower and becomes further lower as d U increases. Due to unphysically positive U and significantly larger |S|, μ from the DRISM theory becomes too high. It is interesting that μ, U, and S from the K-H closure are worse than those from the HNC closure. Overall, the results from the DRISM theory with a molecular model for water are quite similar to those from the RSIE theory with the hard-sphere solvent. Based on the results of the MA analysis, we comparatively discuss the different theoretical methods for cases where they are applied to studies on the solvation of a protein.

  8. Influence of Solvent-Solvent and Solute-Solvent Interaction Properties on Solvent-Mediated Potential

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shi-Qi

    2005-01-01

    A recently proposed universal calculational recipe for solvent-mediated potential is applied to calculate excess potential of mean force between two large Lennard-Jones (LJ) or hard core attractive Yukawa particles immersed in small LJ solvent bath at supercritical state. Comparison between the present prediction with a hypernetted chain approximation adopted for solute-solute correlation at infinitely dilute limit and existing simulation data shows high accuracy for the region with large separation, and qualitative reliability for the solute particle contact region. The calculational simplicity of the present recipe allows for a detailed investigation on the effect of the solute-solvent and solvent-solvent interaction details on the excess potential of mean force. The resultant conclusion is that gathering of solvent particles near a solute particle leads to repulsive excess PMF, while depletion of solvent particles away from the solute particle leads to attractive excess PMF, and minor change of the solvent-solvent interaction range has large influence on the excess PMF.

  9. Determination of atenolol in human plasma using ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Zeeb, Mohsen; Farahani, Hadi; Papan, Mohammad Kazem

    2016-06-01

    An efficient analytical method called ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography was developed for the determination of atenolol in human plasma. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by the addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to a sample solution containing an ion-pairing agent during microextraction. The analyte was extracted into the ionic liquid phase while the microextraction solvent was dispersed throughout the sample by utilizing ultrasound. The sample was then centrifuged, and the extracting phase retracted into the microsyringe and injected to liquid chromatography. After optimization, the calibration curve showed linearity in the range of 2-750 ng/mL with the regression coefficient corresponding to 0.998. The limits of detection (S/N = 3) and quantification (S/N = 10) were 0.5 and 2 ng/mL, respectively. A reasonable relative recovery range of 90-96.7% and satisfactory intra-assay (4.8-5.1%, n = 6) and interassay (5.0-5.6%, n = 9) precision along with a substantial sample clean-up demonstrated good performance of the procedure. It was applied for the determination of atenolol in human plasma after oral administration and some pharmacokinetic data were obtained.

  10. Alternative Green Solvents Project

    Science.gov (United States)

    Maloney, Phillip R.

    2012-01-01

    Necessary for safe and proper functioning of equipment. Mainly halogenated solvents. Tetrachloride, Trichloroethylene (TCE), CFC-113. No longer used due to regulatory/safety concerns. Precision Cleaning at KSC: Small % of total parts. Used for liquid oxygen (LOX) systems. Dual solvent process. Vertrel MCA (decafluoropentane (DFP) and trons-dichloroethylene) HFE-7100. DFP has long term environmental concerns. Project Goals: a) Identify potential replacements. b) 22 wet chemical processes. c) 3 alternative processes. d) Develop test procedures. e) Contamination and cleaning. f) Analysis. g) Use results to recommend alternative processes. Conclusions: a) No alternative matched Vertrel in this study. b) No clear second place solvent. c) Hydrocarbons- easy; Fluorinated greases- difficult. d) Fluorinated component may be needed in replacement solvent. e) Process may need to make up for shortcoming of the solvent. f) Plasma and SCC02 warrant further testing.

  11. A novel poly(deep eutectic solvent)-based magnetic silica composite for solid-phase extraction of trypsin.

    Science.gov (United States)

    Xu, Kaijia; Wang, Yuzhi; Li, Yixue; Lin, Yunxuan; Zhang, Haibao; Zhou, Yigang

    2016-11-23

    Novel poly(deep eutectic solvent) grafted silica-coated magnetic microspheres (Fe3O4@SiO2-MPS@PDES) were prepared by polymerization of choline chloride-itaconic acid (ChCl-IA) and γ-MPS-modified magnetic silica composites, and were characterized by vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectra (XPS), thermal gravimetric analysis (TGA) and transmission electron microscope (TEM). Then the synthetic Fe3O4@SiO2-MPS@PDES microspheres were applied for the magnetic solid-phase extraction (MSPE) of trypsin for the first time. After extraction, the concentration of trypsin in the supernatant was determined by a UV-vis spectrophotometer. Single factor experiments were carried out to investigate the effects of the extraction process, including the concentration of trypsin, the ionic strength, the pH value, the extraction time and the temperature. Experimental results showed the extraction capacity could reach up to 287.5 mg/g under optimized conditions. In comparison with Fe3O4@SiO2-MPS, Fe3O4@SiO2-MPS@PDES displayed higher extraction capacity and selectivity for trypsin. According to the regeneration studies, Fe3O4@SiO2-MPS@PDES microspheres can be recycled six times without significant loss of its extraction capacity, and retained a high extraction capacity of 233 mg/g after eight cycles. Besides, the activity studies also demonstrated that the activity of the extracted trypsin was well retained. Furthermore, the analysis of real sample revealed that the prepared magnetic microspheres can be used to purify trypsin in crude bovine pancreas extract. These results highlight the potential of the proposed Fe3O4@SiO2-MPS@PDES-MSPE method in separation of biomolecules.

  12. Modulation of Electron Injection Dynamics of Ru-Based Dye/TiO2 System in the Presence of Three Different Organic Solvents: Role of Solvent Dipole Moment and Donor Number.

    Science.gov (United States)

    Mahanta, Subrata; Matsuzaki, Hiroyuki; Murakami, Takurou N; Katoh, Ryuzi; Matsumoto, Hajime; Furube, Akihiro

    2015-06-08

    In the present work, femtosecond transient absorption spectroscopy (fs-TAS) has been employed to investigate the electron injection efficiency (EIE) both from the singlet and triplet excited states of a well-known ruthenium dye (N719) to the conduction band (CB) of nanostructured TiO(2) in presence of three different organic solvents [γ-butylactone (GBL), 3-methoxypropionitrile (MPN), and dimethylformamide (DMF)] with different donor numbers (DNs) and dipole moments (DMs). The DM and DN of a solvent modulates the CB edge energy of TiO(2), and this effect reflects well in the fs-TAS results, which shows an EIE trend following the order GBL≥MPN≫DMF, that is, highest in GBL and lowest in DMF solvent environments. Fs-TAS results indicate a lower contribution of electron injection from both the singlet and triplet states in DMF, for which the dominant adsorption of DMF molecules on the TiO(2) surface seems to play an important role in the mechanism.

  13. Temperature-based on-column solute focusing in capillary liquid chromatography reduces peak broadening from pre-column dispersion and volume overload when used alone or with solvent-based focusing.

    Science.gov (United States)

    Groskreutz, Stephen R; Horner, Anthony R; Weber, Stephen G

    2015-07-31

    On-column focusing is essential for satisfactory performance using capillary scale columns. On-column focusing results from generating transient conditions at the head of the column that lead to high solute retention. Solvent-based on-column focusing is a well-known approach to achieve this. Temperature-assisted on-column focusing (TASF) can also be effective. TASF improves focusing by cooling a short segment of the column inlet to a temperature that is lower than the column temperature during the injection and then rapidly heating the focusing segment to the match the column temperature. A troublesome feature of an earlier implementation of TASF was the need to leave the capillary column unpacked in that portion of the column inside the fitting connecting it to the injection valve. We have overcome that problem in this work by packing the head of the column with solid silica spheres. In addition, technical improvements to the TASF instrumentation include: selection of a more powerful thermo-electric cooler to create faster temperature changes and electronic control for easy incorporation into conventional capillary instruments. Used in conjunction with solvent-based focusing and with isocratic elution, volumes of paraben samples (esters of p-hydroxybenzoic acid) up to 4.5-times the column liquid volume can be injected without significant bandspreading due to volume overload. Interestingly, the shapes of the peaks from the lowest volume injections that we can make, 30nL, are improved when using TASF. TASF is very effective at reducing the detrimental effects of pre-column dispersion using isocratic elution. Finally, we show that TASF can be used to focus the neuropeptide galanin in a sample solvent with elution strength stronger than the mobile phase. Here, the stronger solvent is necessitated by the need to prevent peptide adsorption prior to and during analysis.

  14. Solvent-mediated secondary building units (SBUs) diversification in a series of MnII-based metal-organic frameworks (MOFs)

    Science.gov (United States)

    Niu, Yan-Fei; Cui, Li-Ting; Han, Jie; Zhao, Xiao-Li

    2016-09-01

    The role of auxiliary solvents in the formation of MOFs has been investigated for a series of MnII-based framework systems. Reactions of 4,4‧,4″-nitrilotribenzoic acid (H3L) with MnII through varying auxiliary solvents of the medium resulted in the formation of diversified multinuclear MnII subunits in four new coordination polymers: [Mn3(L)(HCOO)3(DEF)3] (1), [Mn3(L)2(EtOH)2]·DMF (2), [Mn5(L)4(H2O)2]·2(H2NMe2)+·4DMF·2H2O (3), and [Mn3(L)2(py)4(H2O)]·H2O (4) (H3L=4,4‧,4‧-nitrilotribenzoic acid, DMF=dimethylformamide, DEF=N,N-diethylformamide, py=pyridine). These four compounds were fully characterized by single-crystal X-ray diffraction, showing interesting SBUs variations. For compound 1, it displays a (3,6)-connected kgd net with wheel [Mn6] cluster serving as SBU, whereas in 2, the sequence of Mn3(COO)9(EtOH)2 is repeated by inversion centers located between Mn1 and Mn3 to form an infinite Mn-carboxylate chain, which are further interlinked by L3- ligands to form a 3D architecture. In 3, the pentanuclear Mn5(CO2)12 clusters are interlinked to form a layer, which are further pillared by L3- to generate a 3D network. Compound 4 has a (3,6)-connected network in which the SBU is a linear trimeric Mn3(COO)6(py)4(H2O) cluster. In addition, the thermal stabilities, X-ray powder diffraction of all the compounds were studied, photoluminescence behaviors of compounds 1, 3 and 4 are discussed.

  15. Comparative study of corn stover pretreated by dilute acid and cellulose solvent-based lignocellulose fractionation: Enzymatic hydrolysis, supramolecular structure, and substrate accessibility.

    Science.gov (United States)

    Zhu, Zhiguang; Sathitsuksanoh, Noppadon; Vinzant, Todd; Schell, Daniel J; McMillan, James D; Zhang, Y-H Percival

    2009-07-01

    Liberation of fermentable sugars from recalcitrant biomass is among the most costly steps for emerging cellulosic ethanol production. Here we compared two pretreatment methods (dilute acid, DA, and cellulose solvent and organic solvent lignocellulose fractionation, COSLIF) for corn stover. At a high cellulase loading [15 filter paper units (FPUs) or 12.3 mg cellulase per gram of glucan], glucan digestibilities of the corn stover pretreated by DA and COSLIF were 84% at hour 72 and 97% at hour 24, respectively. At a low cellulase loading (5 FPUs per gram of glucan), digestibility remained as high as 93% at hour 24 for the COSLIF-pretreated corn stover but reached only approximately 60% for the DA-pretreated biomass. Quantitative determinations of total substrate accessibility to cellulase (TSAC), cellulose accessibility to cellulase (CAC), and non-cellulose accessibility to cellulase (NCAC) based on adsorption of a non-hydrolytic recombinant protein TGC were measured for the first time. The COSLIF-pretreated corn stover had a CAC of 11.57 m(2)/g, nearly twice that of the DA-pretreated biomass (5.89 m(2)/g). These results, along with scanning electron microscopy images showing dramatic structural differences between the DA- and COSLIF-pretreated samples, suggest that COSLIF treatment disrupts microfibrillar structures within biomass while DA treatment mainly removes hemicellulose. Under the tested conditions COSLIF treatment breaks down lignocellulose structure more extensively than DA treatment, producing a more enzymatically reactive material with a higher CAC accompanied by faster hydrolysis rates and higher enzymatic digestibility.

  16. Development of a microfluidic-chip system for liquid-phase microextraction based on two immiscible organic solvents for the extraction and preconcentration of some hormonal drugs.

    Science.gov (United States)

    Asl, Yousef Abdossalami; Yamini, Yadollah; Seidi, Shahram

    2016-11-01

    In the present study, for the first time, an on-chip liquid phase microextraction (LPME) coupled with high performance liquid chromatography was introduced for the analysis of levonorgestrel (Levo), dydrogesterone (Dydo) and medroxyprogesterone (Medo) as the model analytes in biological samples. The chip-based LPME set-up was composed of two polymethyl methacrylate (PMMA) plates with microfabricated channels and a microporous membrane sandwiched between them to separate the sample solution and acceptor phase. These channels were used as a flow path for the sample solution and a thin compartment for the acceptor phase, respectively. In this system, two immiscible organic solvents were used as supported liquid membrane (SLM) and acceptor phase, respectively. During extraction, the model analytes in the sample solution were transported through the SLM (n-dodecane) into the acceptor organic solvent (methanol). The new set-up provided effective and reproducible extractions using low volumes of the sample solution. The effective parameters on the extraction efficiency of the model analytes were optimized using one variable at a time method. Under the optimized conditions, the new set-up provided good linearity in the range of 5.0-500µgL(-1) for the model analytes with the coefficients of determination (r(2)) higher than 0.9909. The relative standard deviations (RSDs%) and limits of detection (LODs) values were less than 6.5% (n=5) and 5.0µgL(-1), respectively. The preconcentration factors (PFs) were obtained using 1.0mL of the sample solution and 20.0µL of the acceptor solution higher than 19.9-fold. Finally, the proposed method was successfully applied for the extraction and determination of the model analytes in urine samples.

  17. PSE For Solvent Applications: A Generic Computer-aided Solvent Selection and Design Framework

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Sin, Gürkan; Gani, Rafiqul

    Solvents are widely used across a number of industries in many applications such as separation agents, reaction mediums, cleaning agents and product carriers. Selection of optimal solvents in these applications is mostly based on previous experiences and experimental trial and error. A process sy...

  18. The orientation of solvent-dipoles at the surface of the pure solvent

    NARCIS (Netherlands)

    Nedermeijer-Denessen, H.J.M.; Ligny, C.L. de

    1975-01-01

    A method is described for the assessment of the preferential orientation of solvent-dipoles at the surface of the solvent from the surface potential χ and its temperature coefficient, dχ/dT. The method is based on the model of Levine et al. of the Stern inner region at the mercury-water interface in

  19. Uniform Treatment of Solute-Solvent Dispersion in the Ground and Excited Electronic States of the Solute Based on a Solvation Model with State-Specific Polarizability.

    Science.gov (United States)

    Marenich, Aleksandr V; Cramer, Christopher J; Truhlar, Donald G

    2013-08-13

    We present a new kind of treatment of the solute-solvent dispersion contribution to the free energy of solvation using a solvation model with state-specific polarizability (SMSSP). To evaluate the solute-solvent dispersion contribution, the SMSSP model utilizes only two descriptors, namely, the spherically averaged dipole polarizability of the solute molecule (either in its ground or excited electronic state) and the refractive index of the solvent. The model was parametrized over 643 ground-state solvation free energy data for 231 solutes in 14 nonpolar, non-hydrogen-bonding solvents. We show that the SMSSP model is applicable to solutes in both the ground and the excited electronic state. For example, in comparison to available experimental data, the model yields qualitatively accurate predictions of the solvatochromic shifts for a number of systems where solute-solvent dispersion is the dominant contributor to the shift.

  20. Cleaning without chlorinated solvents

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.M.; Simandl, R.F.

    1994-12-31

    Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92%. The program has been a twofold effort. Vapor degreasers used in batch cleaning-operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting and bonding. Cleaning ability was determined using techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes and swelling of epoxies.

  1. Effect of solvents on propylene epoxidation over TS-1 catalyst

    Institute of Scientific and Technical Information of China (English)

    Yulong WU; Qingshan LIU; Xueli SU; Zhentao MI

    2008-01-01

    Solvents have an important effect on the epoxidation of propylene catalyzed by TS-1. The experimental results show that, in different solvents, the catalytic activity of epoxidation is in the following order: methanol > 2-propanol > 2-butanol > acetoni-trile > acetone > tetrahydrofuran. Based on the reaction mechanism, the effects of solvents on the epoxidation were studied from eight aspects, which included the electronic effect, the steric effect, the polarity of solvent, the effect of solvent on sorption and diffusion of reactant, the oxidation of alcohol, the etherification of PO, the deactivation of TS-1 and the solubility of propylene in the solvents. The electronic effect, steric effect and the polarity of solvent were considered to be the main aspects. This work may provide theoretical guidance for choosing solvents for these kinds of reactions and also may serve as basis for further industrialization.

  2. Chemical reactions in solvents and melts

    CERN Document Server

    Charlot, G

    1969-01-01

    Chemical Reactions in Solvents and Melts discusses the use of organic and inorganic compounds as well as of melts as solvents. This book examines the applications in organic and inorganic chemistry as well as in electrochemistry. Organized into two parts encompassing 15 chapters, this book begins with an overview of the general properties and the different types of reactions, including acid-base reactions, complex formation reactions, and oxidation-reduction reactions. This text then describes the properties of inert and active solvents. Other chapters consider the proton transfer reactions in

  3. A solvent/non-solvent system for achieving solution-processed multilayer organic light-emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yue; Wu, Zhaoxin, E-mail: zhaoxinwu@mail.xjtu.edu.cn; He, Lin; Jiao, Bo; Hou, Xun

    2015-08-31

    We developed a solvent/non-solvent system to fabricate the multilayer organic light-emitting devices (OLEDs) based on poly(N-vinylcarbazole) (PVK) by solution-process. This solvent system consists of both the solvent and non-solvent of PVK, in which fluorescent small molecules could be fully dissolved and directly spin-coated on top of the PVK layer; it could effectively avoid the redissolution of PVK during the spin-coating process of small molecules emitting layer. In the further investigation of this system, we also demonstrated the three-component solvent system, and found out that the third component, a less volatile solvent of PVK, was crucial for preparing a smoother interface between PVK and emitting layer. Compared with OLEDs through the vacuum deposition, the devices fabricated by solution-process from the solvent/non-solvent system showed comparable efficiency, which indicate that the solvent/non-solvent system can be used as an alternative process to prepare the polymer and small molecule multilayer devices through all-solution-process. - Highlights: • We fabricate the multilayer OLEDs by solution-process using a novel system. • We develop a solvent/non-solvent system of polymer (PVK) to avoid redissolution. • Small molecules could be fully dissolved and directly spin-coated on PVK layer. • The devices fabricated by the system and vacuum deposition show comparable efficiency.

  4. A molecular dynamics study of intramolecular proton transfer reaction of malonaldehyde in solution based upon a mixed quantum–classical approximation. II. Proton transfer reaction in non-polar solvent

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, H.; Yamada, A.; Okazaki, S., E-mail: okazaki@apchem.nagoya-u.ac.jp [Department of Applied Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2015-05-07

    The intramolecular proton transfer reaction of malonaldehyde in neon solvent has been investigated by mixed quantum–classical molecular dynamics (QCMD) calculations and fully classical molecular dynamics (FCMD) calculations. Comparing these calculated results with those for malonaldehyde in water reported in Part I [A. Yamada, H. Kojima, and S. Okazaki, J. Chem. Phys. 141, 084509 (2014)], the solvent dependence of the reaction rate, the reaction mechanism involved, and the quantum effect therein have been investigated. With FCMD, the reaction rate in weakly interacting neon is lower than that in strongly interacting water. However, with QCMD, the order of the reaction rates is reversed. To investigate the mechanisms in detail, the reactions were categorized into three mechanisms: tunneling, thermal activation, and barrier vanishing. Then, the quantum and solvent effects were analyzed from the viewpoint of the reaction mechanism focusing on the shape of potential energy curve and its fluctuations. The higher reaction rate that was found for neon in QCMD compared with that found for water solvent arises from the tunneling reactions because of the nearly symmetric double-well shape of the potential curve in neon. The thermal activation and barrier vanishing reactions were also accelerated by the zero-point energy. The number of reactions based on these two mechanisms in water was greater than that in neon in both QCMD and FCMD because these reactions are dominated by the strength of solute–solvent interactions.

  5. Solvent-induced red-shifts for the proton stretch vibrational frequency in a hydrogen-bonded complex. 1. A valence bond-based theoretical approach.

    Science.gov (United States)

    Kiefer, Philip M; Pines, Ehud; Pines, Dina; Hynes, James T

    2014-07-17

    A theory is presented for the proton stretch vibrational frequency νAH for hydrogen (H-) bonded complexes of the acid dissociation type, that is, AH···B ⇔ A(-)···HB(+)(but without complete proton transfer), in both polar and nonpolar solvents, with special attention given to the variation of νAH with the solvent's dielectric constant ε. The theory involves a valence bond (VB) model for the complex's electronic structure, quantization of the complex's proton and H-bond motions, and a solvent coordinate accounting for nonequilibrium solvation. A general prediction is that νAH decreases with increasing ε largely due to increased solvent stabilization of the ionic VB structure A(-)···HB(+) relative to the neutral VB structure AH···B. Theoretical νAH versus 1/ε slope expressions are derived; these differ for polar and nonpolar solvents and allow analysis of the solvent dependence of νAH. The theory predicts that both polar and nonpolar slopes are determined by (i) a structure factor reflecting the complex's size/geometry, (ii) the complex's dipole moment in the ground vibrational state, and (iii) the dipole moment change in the transition, which especially reflects charge transfer and the solution phase proton potential shapes. The experimental proton frequency solvent dependence for several OH···O H-bonded complexes is successfully accounted for and analyzed with the theory.

  6. Cost-Benefit Analysis of Nanoparticle Albumin-Bound Paclitaxel versus Solvent-Based Paclitaxel for the Treatment of Metastatic Breast Cancer in the United States

    Science.gov (United States)

    Vichansavakul, Kittaya

    Breast cancer is the second leading cause of death among women in the US. Although early detection and treatment help to increase survival rates, some unfortunate patients develop metastatic breast cancer that has no cure. Palliative treatment is the main objective in this group of patients in order to prolong life and reduce toxicities from interventions. In the advancement of treatment for metastatic breast cancer, solvent-based paclitaxel has been widely used. However, solvent-based paclitaxel often causes adverse reactions. Therefore, researchers have developed a new chemotherapy based on nanotechnology. One of these drugs is the Nanoparticle albumin-bound Paclitaxel. This nanodrug aims to increase therapeutic index by reducing adverse reactions from solvents and to improve efficacy of conventional cytotoxic chemotherapy. Breast cancer is a disease with high epidemiological and economic burden. The treatment of metastatic breast cancer has not only high direct costs but also high indirect costs. Breast cancer affects mass populations, especially women younger than 50 years of age. It relates to high indirect costs due to lost productivity and premature death because the majority of these patients are in the workforce. Because of the high cost of breast cancer therapies and short survival rates, the question is raised whether the costs and benefits are worth paying or not. Due to the rising costs in healthcare and new financing policies that have been developed to address this issue, economic evaluation is an important aspect of the development and use of any new interventions. To guide policy makers on how to allocate limited healthcare resources in the most efficient and effective manner, many economic evaluation methods can be used to measure the costs, benefits, and impacts of healthcare innovations. Currently, economic evaluation and health outcomes studies have focused greatly on cost-effectiveness and cost-utility analysis. However, the previous studies

  7. Purex process solvent: literature review

    Energy Technology Data Exchange (ETDEWEB)

    Geier, R.G.

    1979-10-01

    This document summarizes the data on Purex process solvent presently published in a variety of sources. Extracts from these various sources are presented herein and contain the work done, the salient results obtained, and the original, unaltered conclusions of the author of each paper. Three major areas are addressed: solvent stability, solvent quality testing, and solvent treatment processes. 34 references, 44 tables.

  8. Temperature-stabilized silicon-based surface-acoustic-wave gas sensors for the detection of solvent vapors

    Science.gov (United States)

    Bender, Stefan; Mokwa, W.

    1998-12-01

    In the current paper a dual-delay-line- and a resonator- device based on CMOS-silicon-technology is presented. As a piezoelectric layer ZnO is used. The layer was deposited at room temperature in a RF magnetron sputter process. Using x- ray diffraction it could be shown that the crystals are mostly oriented with the c-axis (hexagonal structure) perpendicular to the surface which is necessary to conduct surface acoustic waves. Pt electrodes were designed for frequencies between 140 and 600 MHz and were deposited on top using a lift-off-process. A poly-silicon heating resistor was integrated as a sublayer for controlling and changing of the temperature of the SAW-device for studying the influence of temperature on the mass sensitive layer. A Pt thin film resistance served for temperature measurement. The performance of the devices were compared to standard quartz based SAWs.

  9. Development and optimization of a naphthoic acid-based ionic liquid as a "non-organic solvent microextraction" for the determination of tetracycline antibiotics in milk and chicken eggs.

    Science.gov (United States)

    Gao, Jiajia; Wang, Hui; Qu, Jingang; Wang, Huili; Wang, Xuedong

    2017-01-15

    In traditional ionic liquids (ILs)-based microextraction, ILs are often used as extraction and dispersive solvents; however, their functional effects are not fully utilized. Herein, we developed a novel ionic liquid 1-butyl-3-methylimidazolium naphthoic acid salt ([C4MIM][NPA]) with strong acidity. It was used as a mixed dispersive solvent with conventional [C2MIM][BF4] in "functionalized ionic liquid-based non-organic solvent microextraction (FIL-NOSM)" for determination of tetracycline antibiotics (TCs) in milk and eggs. Utilization of [C4MIM][NPA] in FIL-NOSM method increased extraction recoveries (ERs) of TCs by more than 20% and eliminated the pH adjustment step because of its strong acidity. Under optimized conditions based on central composite design, the ERs of four TCs were 94.1-102.1%, and the limitsofdetection were 0.08-1.12μgkg(-1) in milk and egg samples. This proposed method provides high extraction efficiency, less pretreatment time and requires non-organic solvents for determination of trace TC concentrations in complex animal-based food matrices.

  10. Human and environmental impact assessment of postcombustion CO2 capture focusing on emissions from amine-based scrubbing solvents to air.

    Science.gov (United States)

    Veltman, Karin; Singh, Bhawna; Hertwich, Edgar G

    2010-02-15

    Carbon Capture and Storage (CCS) has become a key technology in climate change mitigation programs worldwide. CCS is well-studied in terms of greenhouse gas emission reduction potential and cost of implementation. Impacts on human health and the environment have, however, received considerably less attention. In this work, we present a first assessment of human health and environmental impacts of a postcombustion CO(2) capture facility, focusing on emissions from amine-based scrubbing solvents and their degradation products to air. We develop characterization factors for human toxicity for monoethanolamine (MEA) as these were not yet available. On the basis of the limited information available, our assessment indicates that amine-based scrubbing results in a 10-fold increase in toxic impact on freshwater ecosystems and a minor increase in toxic impacts on terrestrial ecosystems. These increases are attributed to emissions of monoethanolamine. For all other impact categories, i.e., human toxicity, marine ecotoxicity, particulate matter formation, photochemical oxidant formation, and terrestrial acidification, the CO(2) capture facility performs equally well to a conventional NGCC power plant, albeit substantial changes in flue gas composition. The oxidative degradation products of MEA, i.e., formaldehyde, acetaldehyde, and ammonia, do not contribute significantly to total environmental impacts.

  11. A comparison of chilled DI water/ozone and CO{sub 2}-based supercritical fluids as replacements for photoresist-stripping solvents

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, J.B.; Davenhall, L.B.; Barton, J.; Taylor, C.M.V. [Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.; Tiefert, K. [Hewlett-Packard Co., Santa Clara, CA (United States)

    1998-12-31

    Part of the Hewlett Packard Components Group`s Product Stewardship program is the ongoing effort to investigate ways to eliminate or reduce as much as possible the use of chemical substances from manufacturing processes. Currently used techniques to remove hard-baked photoresists from semiconductor wafers require the use of inorganic chemicals or organic strippers and associated organic solvents. Environmental, health and safety, as well as cost considerations prompted the search for alternative, more environmentally-benign, and cost-effective solutions. Two promising, emerging technologies were selected for evaluation: the chilled DI water/ozone technique and supercritical fluids based on carbon dioxide (CO{sub 2}). Evaluating chilled DI water/ozone shows this process to be effective for positive photoresist removal, but may not be compatible with all metallization systems. Testing of a closed-loop CO{sub 2}-based supercritical CO{sub 2} Resist Remover, or SCORR, at Los Alamos, on behalf of Hewlett-packard, shows that this treatment process is effective in removing photoresists, and is fully compatible with commonly used metallization systems. In this paper, the authors present details on the testing programs conducted with both the chilled DI H{sub 2}O/ozone and SCORR treatment processes.

  12. Single Stage Contactor Testing Of The Next Generation Solvent Blend

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

    2014-01-06

    The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

  13. Method for Predicting Solubilities of Solids in Mixed Solvents

    DEFF Research Database (Denmark)

    Ellegaard, Martin Dela; Abildskov, Jens; O'Connell, J. P.

    2009-01-01

    A method is presented for predicting solubilities of solid solutes in mixed solvents, based on excess Henry's law constants. The basis is statistical mechanical fluctuation solution theory for composition derivatives of solute/solvent infinite dilution activity coefficients. Suitable approximations...... are made for a single parameter characterizing solute/solvent interactions. Comparisons with available data show that the method is successful in describing a variety of observed mixed solvent solubility behavior, including nearly ideal systems with small excess solubilities, systems with solute......-independent excess solubilities, and systems deviating from these simple rules. Successful predictions for new solvent mixtures cat? be made using limited data from other mixtures....

  14. Halogenated solvent remediation

    Science.gov (United States)

    Sorenson, Kent S.

    2004-08-31

    Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.

  15. Single-stranded DNA detection by solvent-induced assemblies of a metallo-peptide-based complex

    Science.gov (United States)

    Das, Priyadip; Reches, Meital

    2016-05-01

    DNA detection is highly important for the sensitive sensing of different pathogenic bacteria and viruses. The major challenge is to create a sensor that can selectively detect very small concentrations of DNA without the need for amplification or complicated equipment. Different technologies such as optical, electrochemical and microgravimetric approaches can detect DNA fragments. Here we show, for the first time, the use of self-assembled nanostructures generated by a metallo-peptide as an optical sensing platform for DNA detection. The system can selectively detect single stranded DNA fragments by fluorescence measurements as it can discriminate even one base mismatch and can perform in the presence of other interfering proteins. This system may be useful in lab-on-a-chip applications.DNA detection is highly important for the sensitive sensing of different pathogenic bacteria and viruses. The major challenge is to create a sensor that can selectively detect very small concentrations of DNA without the need for amplification or complicated equipment. Different technologies such as optical, electrochemical and microgravimetric approaches can detect DNA fragments. Here we show, for the first time, the use of self-assembled nanostructures generated by a metallo-peptide as an optical sensing platform for DNA detection. The system can selectively detect single stranded DNA fragments by fluorescence measurements as it can discriminate even one base mismatch and can perform in the presence of other interfering proteins. This system may be useful in lab-on-a-chip applications. Electronic supplementary information (ESI) available: Peptide and receptor synthesis, characterization of the final and intermediate products, experimental details and additional figures including SEM, TEM, DLS, XRD, UV analysis and AFM topographic analysis. See DOI: 10.1039/c5nr07714a

  16. A micro-system based on glass-nanoporous silicon for optical sensing of organic solvent vapor.

    Science.gov (United States)

    Kim, Young-You; Kim, Han-Jung; Kim, Ho-Jong; Choi, Dae-Geun; Cheng, Horchhong

    2012-06-01

    We present a recent experimental study on the application of nanoporous silicon (np-Si) to an optical vapor sensor. We fabricated the micro-system based on a glass-nanoporous silicon layer on a p(+)-type silicon wafer. To check the selectivity and sensitivity of the np-Si layer to organic vapors, we prepared three types of np-Si layer samples--a single layer, distributed Bragg reflector (DBR) layer, and microcavity layer--and investigated its reflectance spectra upon exposure to different concentrations of various organic vapors. When the np-Si layer samples were exposed to the organic vapors, a red-shift occurred in the reflectance spectrum, and we determined that this red-shift can be attributed to the changes in the refractive index induced by the capillary condensation of the organic vapor within the pores of the np-Si layer. The np-Si layer samples showed excellent sensing ability to different types and concentrations of organic vapors. After removing the organic vapors, the reflectance spectrum immediately returned to its original state.

  17. Optical properties of a long dynamic range chemical UV dosimeter based on solvent cast polyvinyl chloride (PVC).

    Science.gov (United States)

    Amar, Abdurazaq; Parisi, Alfio V

    2013-11-01

    The dosimetric properties of the recently introduced UV dosimeter based on 16 μm PVC film have been fully characterised. Drying the thin film in air at 50 °C for at least 28 days was found to be necessary to minimise the temperature effects on the dosimeter response. This research has found that the dosimeter response, previously reported to be mainly to UVB, has no significant dependence on either exposure temperature or dose rate. The dosimeter has negligible dark reaction and responds to the UV radiation with high reproducibility. The dosimeter angular response was found to have a similar pattern as the cosine function but deviates considerably at angles larger than 70°. Dose response curves exhibit monotonically increasing shape and the dosimeter can measure more than 900 SED. This is about 3 weeks of continuous exposure during summer at subtropical sites. Exposures measured by the PVC dosimeter for some anatomical sites exposed to solar radiation for twelve consecutive days were comparable with those concurrently measured by a series of PPO dosimeters and were in line with earlier results reported in similar studies.

  18. 基于化学溶剂的焦油冷凝净化技术试验%EXPERIMENTAL STUDY OF TAR CONDENSING REMOVAL BASED ON CHEMICAL SOLVENTS

    Institute of Scientific and Technical Information of China (English)

    郭飞强; 董玉平; 景元琢; 董磊

    2012-01-01

    利用化学溶剂冷凝捕集的方法,使燃气中的焦油颗粒凝结沉积.通过试验,对3种典型的溶剂净化性能进行对比分析,从中筛选出性能优良的溶剂,并试验研究溶剂流量与净化性能的关系,结果表明燃气流速为70m3/h、溶剂流量约为250L/h时,焦油的去除效率达到90%,溶剂的损失可控制在一个较小范围内.%According to the tar problem in biomass gas,chemical solvent condensate trapping way was used to make tar particles in the gas condense and deposit.Tar problem could be solved mostly in this way.In the experiment,three typical solvents were comparatively analyzed,and the best solvent was chosen.Then,relationship between flow rate of the best solvent and purification performance was studied.The results show that tar removal efficiency can reach up to 90% when the flow rute of the solvent is 250L/h,also solvent loss will be less.

  19. Fragment-Based Approach for the Evaluation of NMR Chemical Shifts for Large Biomolecules Incorporating the Effects of the Solvent Environment.

    Science.gov (United States)

    Jose, K V Jovan; Raghavachari, Krishnan

    2017-03-14

    We present an efficient implementation of the molecules-in-molecules (MIM) fragment-based quantum chemical method for the evaluation of NMR chemical shifts of large biomolecules. Density functional techniques have been employed in conjunction with large basis sets and including the effects of the solvent environment in these calculations. The MIM-NMR method is initially benchmarked on a set of (alanine)10 conformers containing strong intramolecular interactions. The incorporation of a second low level of theory to recover the missing long-range interactions in the primary fragmentation scheme is critical to yield reliable chemical shifts, with a mean absolute deviation (MAD) from direct unfragmented calculations of 0.01 ppm for (1)H chemical shifts and 0.07 ppm for (13)C chemical shifts. In addition, the performance of MIM-NMR has been assessed on two large peptides: the helical portion of ubiquitin ( 1UBQ ) containing 12 residues where the X-ray structure is known, and E6-binding protein of papilloma virus ( 1RIJ ) containing 23 residues where the structure has been derived from solution-phase NMR analysis. The solvation environment is incorporated in these MIM-NMR calculations, either through an explicit, implicit, or a combination of both solvation models. Using an explicit treatment of the solvent molecules within the first solvation sphere (3 Å) and an implicit solvation model for the rest of the interactions, the (1)H and (13)C chemical shifts of ubiquitin show excellent agreement with experiment (mean absolute deviation of 0.31 ppm for (1)H and 1.72 ppm for (13)C), while the larger E6-binding protein yields a mean absolute deviation of 0.34 ppm for (1)H chemical shifts. The proposed MIM-NMR method is computationally cost-effective and provides a substantial speedup relative to conventional full calculations, the largest density functional NMR calculation included in this work involving more than 600 atoms and over 10,000 basis functions. The MIM

  20. Solvent Extraction Developments in Southern Africa

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The largest solvent-extraction plant in the world at the time, the Nchanga Copper Operation, was in Zambia. The first commercial process using solvent extraction for the refining of the platinum-group metals was in South Africa. More recently, the Southern African region has seen the implementation of solvent extraction for other base metals, precious metals, and specialty metals. These include the world firsts of primary production of zinc at Skorpion Zinc in Namibia and the large-scale refining of gold by Harmony Gold in South Africa. Several other flowsheets that use solvent-extraction technology are currently under commissioning, development, or feasibility study for implementation in this part of the world, including those for the recovery of copper, cobalt, nickel, tantalum, and niobium.

  1. Infrared studies of polyacrylonitrile-based polymer electrolytes incorporated with lithium bis(trifluoromethane)sulfonimide and urea as deep eutectic solvent

    Science.gov (United States)

    Sim, L. N.; Yahya, R.; Arof, A. K.

    2016-06-01

    In this work, urea is introduced into polyacrylonitrile (PAN)-based polymer electrolyte containing lithium bis(trifluoromethane)sulfonimide (LiTFSI) to form a deep eutectic solvent with urea and LiTFSI in the mole ratio of 1:3. The ambient ionic conductivity of the polymer electrolyte film is enhanced from 2.54 × 10-4 S cm-1 to 3.82 × 10-3 S cm-1 with the addition of urea. Infrared studies has revealed that urea interacts with the LiTFSI through coordination of Li+ ions onto the carbonyl (Cdbnd O) group of urea, and hydrogen bonding possibly to the O atoms in the SO2 groups of TFSI- ions. Hydrogen bonding interactions of urea with DMF and PAN are also evident. The enhancement in conductivity is believed to be due to urea being involved in the dissociation of LiTFSI and its role as an additional ion conduction pathway through its carbonyl group.

  2. Morphologies and separation characteristics of polyphenyl sulfone-based solvent resistant nanofiltration membranes: Effect of polymer concentration in casting solution and membrane pretreatment condition

    Energy Technology Data Exchange (ETDEWEB)

    Sani, Nur Aimie Abdullah; Lau, Woei Jye; Ismail, Ahmad Fauzi [Universiti Teknologi Malaysia, Skudai (Malaysia)

    2015-04-15

    The performance of polyphenylsulfone (PPSU) solvent resistant nanofiltration (SRNF)-based flat sheet membranes prepared from phase inversion method was investigated by varying the concentration of polymer in the dope solution and condition of membrane pretreatment process. The membrane properties were characterized by SEM, FTIR, AFM and contact angle goniometer, while their performance was evaluated by measuring methanol flux and rejection of different molecular weight of dyes (ranging from 269 to 1,470 g/mol) in methanol. The experimental results showed that the polymer concentration has great impact not only on the final membrane morphology but also its separation characteristics. Increasing polymer concentration from 17 to 25wt% tended to suppress finger-like structure and more pear-like pores were developed, causing methanol flux to decrease. This can be explained by the decrease in molecular weight cut off (MWCO) of the membrane prepared at high polymer concentration. With respect to the effect of membrane pretreatment conditions, the rejection of membrane was negatively affected with longer immersion period in methanol solution prior to filtration experiment. The variation in membrane rejection can be attributed to the rearrangement of the polymer chain, which results in membrane swelling and/or change of membrane surface hydrophilicity.

  3. Sulfination by using Pd-PEPPSI complexes: studies into precatalyst activation, cationic and solvent effects and the role of butoxide base.

    Science.gov (United States)

    Sayah, Mahmoud; Lough, Alan J; Organ, Michael G

    2013-02-18

    The activation of PEPPSI precatalysts has been systematically studied in Pd-catalysed sulfination. Under the reactions conditions of the sulfide and KOtBu in toluene, the first thing that happens is exchange of the two chlorides on the PEPPSI precatalyst with the corresponding sulfides, creating the first resting state; it is via this complex that all Pd enters the catalytic cycle. However, it is also from this same complex that a tri-Pd complex forms, which is a more persistent resting state. Under standard reaction conditions, this complex is catalytically inactive. However, if additional pyridine or a smaller base (i.e., KOEt) is added, this complex is broken down, presumably initially back to the first resting state and it is again capable of entering the catalytic cycle and completing the sulfination. Of note, once the tri-Pd complex forms, one equivalent of Pd is lost to the transformation. Related to this, the nature of the cation of the sulfide salt and solvent dielectric is very important to the success of this transformation. That is, the less soluble the salt the better the performance, which can be attributed to lowering sulfide concentration to avoid the movement of the Pd-NHC complex into the above described off-cycle sulfinated resting states.

  4. Enabling LiTFSI-based electrolytes for safer lithium-ion batteries by using linear fluorinated carbonates as (Co)solvent.

    Science.gov (United States)

    Kalhoff, Julian; Bresser, Dominic; Bolloli, Marco; Alloin, Fannie; Sanchez, Jean-Yves; Passerini, Stefano

    2014-10-01

    In this Full Paper we show that the use of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as conducting salt in commercial lithium-ion batteries is made possible by introducing fluorinated linear carbonates as electrolyte (co)solvents. Electrolyte compositions based on LiTFSI and fluorinated carbonates were characterized regarding their ionic conductivity and electrochemical stability towards oxidation and with respect to their ability to form a protective film of aluminum fluoride on the aluminum surface. Moreover, the investigation of the electrochemical performance of standard lithium-ion anodes (graphite) and cathodes (Li[Ni1/3 Mn1/3 Co1/3 ]O2 , NMC) in half-cell configuration showed stable cycle life and good rate capability. Finally, an NMC/graphite full-cell confirmed the suitability of such electrolyte compositions for practical lithium-ion cells, thus enabling the complete replacement of LiPF6 and allowing the realization of substantially safer lithium-ion batteries.

  5. Molecular structures of (3-aminopropyl)trialkoxysilane on hydroxylated barium titanate nanoparticle surfaces induced by different solvents and their effect on electrical properties of barium titanate based polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yanyan; Wang, Guanyao; Huang, Xingyi, E-mail: xyhuang@sjtu.edu.cn; Bu, Jing; Sun, Xiaojin; Jiang, Pingkai

    2016-02-28

    Graphical abstract: - Highlights: • The silanization on the surface of hydroxylated barium titanate nanoparticles was introduced by using two kinds of trialkoxysilanes with different solvents (toluene and ethanol), respectively. • Solvents have more remarkable impact on the dielectric properties of the subsequent BT/PVDF nanocomposites than the types of silanes. • The solvents used for BT nanoparticle surface modification exhibit a significant effect on the breakdown strength of the nanocomposites. - Abstract: Surface modification of nanoparticles by grafting silane coupling agents has proven to be a significant approach to improve the interfacial compatibility between inorganic filler and polymer matrix. However, the impact of grafted silane molecular structure after the nanoparticle surface modification, induced by the utilized solvents and the silane alkoxy groups, on the electrical properties of the corresponding nanocomposites, has been seldom investigated. Herein, the silanization on the surface of hydroxylated barium titanate (BT-OH) nanoparticles was introduced by using two kinds of trialkoxysilane, 3-aminopropyltriethoxysilane (AMEO) and 3-aminopropyltrimethoxysilane (AMMO), with different solvents (toluene and ethanol), respectively. Solid-state {sup 13}C, {sup 29}Si nuclear magnetic resonance (NMR) spectroscopy and high-resolution X-ray photoelectron spectroscopy (XPS) were employed to validate the structure differences of alkoxysilane attachment to the nanoparticles. The effect of alkoxysilane structure attached to the nanoparticle surface on the dielectric properties of the BT based poly(vinylidene fluoride) (PVDF) nanocomposites were investigated. The results reveal that the solvents used for BT nanoparticle surface modification exhibit a significant effect on the breakdown strength of the nanocomposites. Nevertheless, the alkoxy groups of silane show a marginal influence on the dielectric properties of the nanocomposites. These research results

  6. ADME evaluation in drug discovery. 2. Prediction of partition coefficient by atom-additive approach based on atom-weighted solvent accessible surface areas.

    Science.gov (United States)

    Hou, T J; Xu, X J

    2003-01-01

    A novel method for the calculations of 1-octanol/water partition coefficient (log P) of organic molecules has been presented here. The method, SLOGP v1.0, estimates the log P values by summing the contribution of atom-weighted solvent accessible surface areas (SASA) and correction factors. Altogether 100 atom/group types were used to classify atoms with different chemical environments, and two correlation factors were used to consider the intermolecular hydrophobic interactions and intramolecular hydrogen bonds. Coefficient values for 100 atom/group and two correction factors have been derived from a training set of 1850 compounds. The parametrization procedure for different kinds of atoms was performed as follows: first, the atoms in a molecule were defined to different atom/group types based on SMARTS language, and the correction factors were determined by substructure searching; then, SASA for each atom/group type was calculated and added; finally, multivariate linear regression analysis was applied to optimize the hydrophobic parameters for different atom/group types and correction factors in order to reproduce the experimental log P. The correlation based on the training set gives a model with the correlation coefficient (r) of 0.988, the standard deviation (SD) of 0.368 log units, and the absolute unsigned mean error of 0.261. Comparison of various procedures of log P calculations for the external test set of 138 organic compounds demonstrates that our method bears very good accuracy and is comparable or even better than the fragment-based approaches. Moreover, the atom-additive approach based on SASA was compared with the simple atom-additive approach based on the number of atoms. The calculated results show that the atom-additive approach based on SASA gives better predictions than the simple atom-additive one. Due to the connection between the molecular conformation and the molecular surface areas, the atom-additive model based on SASA may be a more

  7. Organic solvent topical report

    Energy Technology Data Exchange (ETDEWEB)

    Cowley, W.L.

    1998-04-30

    This report is the technical basis for the accident and consequence analyses used in the Hanford Tank Farms Basis for Interim Operation. The report also contains the scientific and engineering information and reference material needed to understand the organic solvent safety issue. This report includes comments received from the Chemical Reactions Subcommittee of the Tank Advisory Panel.

  8. Organic solvent topical report

    Energy Technology Data Exchange (ETDEWEB)

    COWLEY, W.L.

    1999-05-13

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an organic solvent fire is within risk evaluation guidelines. This report updates information contained in Analysis of Consequences of Postulated Solvent Fires in Hanford Site Waste Tanks. WHC-SD-WM-CN-032. Rev. 0A (Cowley et al. 1996). However, this document will not replace Cowley et al (1996) as the primary reference for the Basis for Interim Operation (BIO) until the recently submitted BIO amendment (Hanson 1999) is approved by the US Department of Energy. This conclusion depends on the use of controls for preventing vehicle fuel fires and for limiting the use of flame cutting in areas where hot metal can fall on the waste surface.The required controls are given in the Tank Waste Remediation System Technical Safety Requirements (Noorani 1997b). This is a significant change from the conclusions presented in Revision 0 of this report. Revision 0 of this calcnote concluded that some organic solvent fire scenarios exceeded risk evaluation guidelines, even with controls imposed.

  9. Low-density solvent-based vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction combined with gas chromatography-mass spectrometry for the fast determination of phthalate esters in bottled water.

    Science.gov (United States)

    Zhang, Yufeng; Lee, Hian Kee

    2013-01-25

    For the first time, a novel low-density solvent-based vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction (LDS-VSLLME) was developed for the fast, simple and efficient determination of six phthalate esters (PEs) in bottled water samples followed by gas chromatography-mass spectrometry (GC-MS). In the extraction procedure, the aqueous sample solution was injected into a mixture of extraction solvent (toluene) and surfactant (cetyltrimethyl ammonium bromide), which were placed in a glass tube with conical bottom, to form an emulsion by the assistance of vortex agitation. After extraction and phase separation by centrifugation, and removal of the spent sample, the toluene extract was collected and analyzed by GC-MS. The addition of surfactant enhanced the dispersion of extraction solvent in aqueous sample and was also favorable for the mass transfer of the analytes from the aqueous sample to the extraction solvent. Moreover, using a relatively less toxic surfactant as the emulsifier agent overcame the disadvantages of traditional organic dispersive solvents that are usually highly toxic and expensive and might conceivably decrease extraction efficiency to some extent since they are not as effective as surfactants themselves in generating an emulsion. With the aid of surfactant and vortex agitation to achieve good organic extraction solvent dispersion, extraction equilibrium was achieved within 1 min, indicating it was a fast sample preparation technique. Another prominent feature of the method was the simple procedure to collect a less dense than water solvent by a microsyringe. After extraction and phase separation, the aqueous sample was removed using a 5-mL syringe, thus leaving behind the extract, which was retrieved easily. This novel method simplifies the use of low-density solvents in DLLME. Under the optimized conditions, the proposed method provided good linearity in the range of 0.05-25 μg/L, low limits of detection (8-25 ng

  10. Influence of imidazolium based green solvents on volume phase transition temperature of crosslinked poly(N-isopropylacrylamide-co-acrylic acid) hydrogel.

    Science.gov (United States)

    Chang, Chi-Jung; Reddy, P Madhusudhana; Hsieh, Shih-Rong; Huang, Hsin-Chun

    2015-01-28

    The volume phase transition temperature (VPTT) of crosslinked poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-co-AA) hydrogel in water in the presence of five imidazolium based ionic liquids (ILs) was studied. The VPTT of PNIPAM-co-AA hydrogel can be modulated to different extents by the addition of different amounts of ILs. The modulations in VPTT values can be attributed to the IL-induced alterations in hydrophobic, hydrophilic and hydrogen bonding interactions of PNIPAM-co-AA hydrogel with the neighboring solvent and molecular chains. The influence of ILs having a common cation, 1-butyl-3-methylimidazolium cation ([Bmim]) and different anions, such as iodide (I-), tetrafluoroborate (BF4-), chloride (Cl-), acetate (CH3COO-) and hydrogen sulfate (HSO4-), on the phase transition of PNIPAM-co-AA hydrogel was monitored by the aid of differential scanning calorimetry (DSC), dynamic light scattering (DLS) and Fourier transform infrared (FT-IR) spectroscopy. Furthermore, the interfacial properties between aqueous IL and polymer surface were scrutinized with the help of contact angle (CA) measurements. The overall specific ranking of ILs in preserving the hydration layer around the PNIPAM-co-AA hydrogel in water was [Bmim][I]>[Bmim][BF4]>[Bmim][Cl]>[Bmim][Ac]>[Bmim][HSO4]. The trend of these ILs followed the well-known Hofmeister series. Interestingly, the PNIPAM-co-AA hydrogel in water shows abnormal salting-out property in the presence of [Bmim][BF4] at higher concentration and this abnormal behavior can be explained based on the lack of sufficient binding sites on the macromolecule for higher number of [Bmim][BF4] at a higher concentration.

  11. Operator care and eco-concerned development of a fast, facile and economical assay for basic nitrogenous drugs based on simplified ion-pair mini-scale extraction using safer solvent combined with drop-based spectrophotometry.

    Science.gov (United States)

    Plianwong, Samarwadee; Sripattanaporn, Areerut; Waewsa-nga, Kwanrutai; Buacheen, Parin; Opanasopit, Praneet; Ngawhirunpat, Tanasait; Rojanarata, Theerasak

    2012-08-30

    A fast, facile, and economical assay for basic nitrogenous drugs has been developed based on the mini-scale extraction of the drug-dye ion pair complex combined with the use of safe-for-analyst and eco-friendlier organic extractant and drop-based micro-spectrophotometry. Instead of using large volume devices, the extraction was simply carried out in typical 1.5 mL microcentrifuge tubes along with the use of micropipettes for accurate transfer of liquids, vortex mixer for efficient partitioning of solutes and benchtop centrifuge for rapid phase separation. In the last step, back-extraction was performed by using the microvolume of acidic solution in order to concentrate the colored species into a confined aqueous microdrop and to keep the analyst away from unwanted contact and inhalation of organic solvents during the quantitation step which was achieved by using cuvetteless UV-vis micro-spectrophotometry without any prior dilutions. Using chlorpheniramine maleate as a representative analyte and n-butyl acetate as a less toxic and non-ozone depleting extractant, the miniaturized method was less laborious and much faster. It was accurate, precise and insensitive to the interferences from common excipients. Notably, it gave the assay results of drug in tablets and oral solution comparable to the large-scale pharmacopeial method while the consumption of organic solvents and the release of wastes were lowered by 200-400 folds.

  12. Ab initio study of solvent-dependent one-, two- and three-photon absorption properties of PRODAN-based chemo-sensors

    Indian Academy of Sciences (India)

    Md Mehboob Alam; Mausumi Chattopadhyaya

    2014-07-01

    In this work, we study the solvent-dependent one-, two- and three-photon absorption (1PA, 2PA and 3PA) properties of 2-propionyl-6-dimethylamino naphthalene (PRODAN) and three newly synthesized20 cyclopenta[b]naphthalene derivatives, in gas phase and three different solvents, namely cyclohexane, dichloromethane and ethanol. A comparison between the calculated and the available experimental data shows that the results obtained with B3LYP/cc-pVDZ level of theory matches well with the experimental absorption data for all of these compounds. The 2P and 3P transition probabilities, for all of these systems, are found to be maximum in solvents of intermediate polarity (here, dichloromethane), which is in accordance with the experimental observation for various other systems. All the 1P, 2P and 3P transition probabilities are found to be the maximum for PRODAN as compared to other three molecules in both the gas as well as the different solvent phases (except for 3PA in gas and cyclohexane solvents). We have explained these results by meticulously inspecting the components of different transition moment vectors and the tensor elements involved.

  13. An attempt towards simultaneous biobased solvent based extraction of proteins and enzymatic saccharification of cellulosic materials from distiller's grains and solubles.

    Science.gov (United States)

    Datta, Saurav; Bals, B D; Lin, Yupo J; Negri, M C; Datta, R; Pasieta, L; Ahmad, Sabeen F; Moradia, Akash A; Dale, B E; Snyder, Seth W

    2010-07-01

    Distiller's grains and solubles (DGS) is the major co-product of corn dry mill ethanol production, and is composed of 30% protein and 30-40% polysaccharides. We report a strategy for simultaneous extraction of protein with food-grade biobased solvents (ethyl lactate, d-limonene, and distilled methyl esters) and enzymatic saccharification of glucan in DGS. This approach would produce a high-value animal feed while simultaneously producing additional sugars for ethanol production. Preliminary experiments on protein extraction resulted in recovery of 15-45% of the protein, with hydrophobic biobased solvents obtaining the best results. The integrated hydrolysis and extraction experiments showed that biobased solvent addition did not inhibit hydrolysis of the cellulose. However, only 25-33% of the total protein was extracted from DGS, and the extracted protein largely resided in the aqueous phase, not the solvent phase. We hypothesize that the hydrophobic solvent could not access the proteins surrounded by the aqueous phase inside the fibrous structure of DGS due to poor mass transfer. Further process improvements are needed to overcome this obstacle.

  14. Simultaneous dispersive liquid-liquid microextraction based on a low-density solvent and derivatization followed by gas chromatography for the simultaneous determination of chloroanisoles and the precursor 2,4,6-trichlorophenol in water samples.

    Science.gov (United States)

    Bai, Xiuzhi; Zhang, Ting; Li, Haipu; Yang, Zhaoguang

    2016-06-01

    Chloroanisoles, particularly 2,4,6-trichloroanisole, are commonly identified as major taste and odor compounds in water. In the present study, a simple and efficient method was established for the simultaneous determination of chloroanisoles and the precursor 2,4,6-trichlorophenol in water by using low-density-solvent-based simultaneous dispersive liquid-liquid microextraction and derivatization followed by gas chromatography with electron capture detection. 2,4-Dichloroanisole, 2,6-dichloroanisole, 2,4,6-trichloroanisole, 2,3,4-trichloroanisole, and 2,3,6-trichloroanisole were the chloroanisoles evaluated. Several important parameters of the extraction-derivatization procedures, including the types and volumes of extraction solvent and disperser solvent, concentrations of derivatization agent and base, salt addition, extraction-derivatization time, and temperature were optimized. Under the optimized conditions (80 μL of isooctane as extraction solvent, 500 μL of methanol as disperser solvent, 60 μL of acetic anhydride as derivatization agent, 0.75% of Na2 CO3 addition w/v, extraction-derivatization temperature of 25°C, without salt addition), a good linearity of the calibration curve was observed by the square of correlation coefficients (R(2) ) ranging from 0.9936 to 0.9992. Repeatability and reproducibility of the method were < 4.5% and <7.3%, respectively. Recovery rates ranged from 85.2 to 101.4%, and limits of detection ranged from 3.0 to 8.7 ng/L. The proposed method was applied successfully for the determination of chloroanisoles and 2,4,6-trichlorophenol in water samples.

  15. Vortex-assisted micro-solid-phase extraction followed by low-density solvent based dispersive liquid-liquid microextraction for the fast and efficient determination of phthalate esters in river water samples.

    Science.gov (United States)

    Guo, Liang; Lee, Hian Kee

    2013-07-26

    A simple and efficient two-step method, vortex-assisted micro-solid-phase extraction (VA-μ-SPE) followed by low-density solvent based dispersive liquid-liquid microextraction (LDS-DLLME) combined with analysis by gas chromatography-mass spectrometry (GC-MS), was developed for the determination of trace level phthalate esters in environmental water samples. The analytes were firstly extracted and preconcentrated by vortex-assisted μ-SPE which was faster than conventional μ-SPE (6min compared to 30min), and then desorbed by ultrasonication into acetonitrile. The latter served as the dispersive solvent in the subsequent LDS-DLLME step which further pre-concentrated the analytes. Six phthalate esters were selected as model compounds for developing and evaluating the method. Some key parameters for VA-μ-SPE and LDS-DLLME, such as sorbent selection and amount, vortex time, ultrasonication solvent and time, extraction solvent type and volume for DLLME, the speed and time of centrifugation, were investigated. Under the most favorable conditions, good limits of detection (as low as 0.006μg/L) and repeatability of extraction (RSDs below 9.2%, n=5) were obtained. The developed method was applied to determine phthalate esters in environmental water samples.

  16. "Abnormal" salt and solvent effects on anion/cation electron-transfer reactions: an interpretation based on Marcus-Hush treatment.

    Science.gov (United States)

    Garcia-Fernandez, E; Prado-Gotor, R; Sanchez, F

    2005-08-11

    Salt and solvent effects on the kinetics of the reactions [Fe(CN)6]3- + [Ru(NH3)5pz](2+) right arrow over left arrow [Fe(CN)6]4- + [Ru(NH3)5pz]3+ (pz = pyrazine) have been studied through T-jump measurements. The forward and reverse reactions show different behaviors: "abnormal" salt and solvent effects in the first case and normal effects in the second one. These facts imply an asymmetric behavior of anion/cation reactions depending on the charge of the oxidant. The results can be rationalized by using the Marcus-Hush treatment for electron-transfer reactions.

  17. Solvent Immersion Imprint Lithography

    Energy Technology Data Exchange (ETDEWEB)

    Vasdekis, Andreas E.; Wilkins, Michael J.; Grate, Jay W.; Kelly, Ryan T.; Konopka, Allan; Xantheas, Sotiris S.; Chang, M. T.

    2014-06-21

    The mechanism of polymer disolution was explored for polymer microsystem prototyping, including microfluidics and optofluidics. Polymer films are immersed in a solvent, imprinted and finally brought into contact with a non-modified surface to permanently bond. The underlying polymer-solvent interactions were experimentally and theoretically investigated, and enabled rapid polymer microsystem prototyping. During imprinting, small molecule integration in the molded surfaces was feasible, a principle applied to oxygen sensing. Polystyrene (PS) was employed for microbiological studies at extreme environmental conditions. The thermophile anaerobe Clostridium Thermocellum was grown in PS pore-scale micromodels, revealing a double mean generation lifetime than under ideal culture conditions. Microsystem prototyping through directed polymer dissolution is simple and accessible, while simultaneous patterning, bonding, and surface/volume functionalization are possible in less than one minute.

  18. Next Generation Solvent Performance in the Modular Caustic Side Solvent Extraction Process - 15495

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Tara E. [Savannah River Remediation, LLC., Aiken, SC (United States); Scherman, Carl [Savannah River Remediation, LLC., Aiken, SC (United States); Martin, David [Savannah River Remediation, LLC., Aiken, SC (United States); Suggs, Patricia [Savannah River Site (SRS), Aiken, SC (United States)

    2015-01-14

    Changes to the Modular Caustic Side Solvent Extraction Unit (MCU) flow-sheet were implemented in the facility. Implementation included changing the scrub and strip chemicals and concentrations, modifying the O/A ratios for the strip, scrub, and extraction contactor banks, and blending the current BoBCalixC6 extractant-based solvent in MCU with clean MaxCalix extractant-based solvent. During the successful demonstration period, the MCU process was subject to rigorous oversight to ensure hydraulic stability and chemical/radionuclide analysis of the key process tanks (caustic wash tank, solvent hold tank, strip effluent hold tank, and decontaminated salt solution hold tank) to evaluate solvent carryover to downstream facilities and the effectiveness of cesium removal from the liquid salt waste. Results indicated the extraction of cesium was significantly more effective with an average Decontamination Factor (DF) of 1,129 (range was 107 to 1,824) and that stripping was effective. The contactor hydraulic performance was stable and satisfactory, as indicated by contactor vibration, contactor rotational speed, and flow stability; all of which remained at or near target values. Furthermore, the Solvent Hold Tank (SHT) level and specific gravity was as expected, indicating that solvent integrity and organic hydraulic stability were maintained. The coalescer performances were in the range of processing results under the BOBCalixC6 flow sheet, indicating negligible adverse impact of NGS deployment. After the Demonstration period, MCU began processing via routine operations. Results to date reiterate the enhanced cesium extraction and stripping capability of the Next Generation Solvent (NGS) flow sheet. This paper presents process performance results of the NGS Demonstration and continued operations of MCU utilizing the blended BobCalixC6-MaxCalix solvent under the NGS flowsheet.

  19. 浅析水性聚氨酯与溶剂型聚氨酯合成革加工工艺区别%Discussion on Difference of Waterborne and Solvent based Polyurethane in Leather Industry

    Institute of Scientific and Technical Information of China (English)

    郑兆祥; 吕海宁; 范新妹; 洪军燕

    2011-01-01

    The difference of structure and condition between waterborne polyurethane and solvent - based polyurethane was discussed, which leads to the changes of processing in leather industry.The basis and mechanism of waterborne and solvent -based polyurethane in choosing wet processing and release paper were pointed out, which provide effective theoretical support for the development of waterborne polyurethane.%分析了水性聚氨酯与溶剂型聚氨酯在分子结构上的不同及其存在状态的差异,而导致其在合成革加工工艺上有所区别,指出了水性与溶剂型聚氨酯在湿法加工和离型纸方面选择的依据与作用机理,为以后水性聚氨酯的发展提供有力的理论支撑.

  20. Advanced integrated solvent extraction systems

    Energy Technology Data Exchange (ETDEWEB)

    Horwitz, E.P.; Dietz, M.L.; Leonard, R.A. [Argonne National Lab., IL (United States)

    1997-10-01

    Advanced integrated solvent extraction systems are a series of novel solvent extraction (SX) processes that will remove and recover all of the major radioisotopes from acidic-dissolved sludge or other acidic high-level wastes. The major focus of this effort during the last 2 years has been the development of a combined cesium-strontium extraction/recovery process, the Combined CSEX-SREX Process. The Combined CSEX-SREX Process relies on a mixture of a strontium-selective macrocyclic polyether and a novel cesium-selective extractant based on dibenzo 18-crown-6. The process offers several potential advantages over possible alternatives in a chemical processing scheme for high-level waste treatment. First, if the process is applied as the first step in chemical pretreatment, the radiation level for all subsequent processing steps (e.g., transuranic extraction/recovery, or TRUEX) will be significantly reduced. Thus, less costly shielding would be required. The second advantage of the Combined CSEX-SREX Process is that the recovered Cs-Sr fraction is non-transuranic, and therefore will decay to low-level waste after only a few hundred years. Finally, combining individual processes into a single process will reduce the amount of equipment required to pretreat the waste and therefore reduce the size and cost of the waste processing facility. In an ongoing collaboration with Lockheed Martin Idaho Technology Company (LMITCO), the authors have successfully tested various segments of the Advanced Integrated Solvent Extraction Systems. Eichrom Industries, Inc. (Darien, IL) synthesizes and markets the Sr extractant and can supply the Cs extractant on a limited basis. Plans are under way to perform a test of the Combined CSEX-SREX Process with real waste at LMITCO in the near future.

  1. Development and validation of an automated extraction method (accelerated solvent extraction) and a reverse-phase HPLC analysis method for assay of ivermectin in a meat-based chewable formulation.

    Science.gov (United States)

    Abend, Andreas M; Chung, Le; McCollum, David G; Wuelfing, W Peter

    2003-04-10

    A new method for monitoring ivermectin content in HEARTGARD CHEWABLES has been developed and validated. The method consists of the automated extraction of ivermectin from the meat-based formulation under conditions of elevated temperature and pressure (accelerated solvent extraction, ASE, and determination of the active by reverse-phase high performance liquid chromatography (HPLC). The method resolves both active species of ivermectin (components H(2)B(1a) and H(2)B(1b)) from the formulation matrix.

  2. Effect of Solvent and Acid-Base on Palladium(ll)-catalyzed Dicarbonylation of Terminal Acetylenes: a General, Efficient andStereoselective Synthesis of Maleic Diesters and Maleic Anhydrides

    Institute of Scientific and Technical Information of China (English)

    JIANG, Huan-Feng; LI, JiN-Heng; CHEN, Ming-Cai

    2001-01-01

    The productions of maleic diesters and maleic anhydrises depend on the effect of solvint and acid-bade of solvent and acid-base in palladium-catalyzed dicarbonylation of terminal acetylenes. For primaryand secondary alcohol in benzene.only maleic diesters wereobtained stereospecifically from the sicabonylation ofacetylenes in the presence of PdCl2,and NaHCO3.For tERTIARy alcohols,maleic anhydrides were synthesized selectively.

  3. Alcohols as hydrogen-donor solvents for treatment of coal

    Science.gov (United States)

    Ross, David S.; Blessing, James E.

    1981-01-01

    A method for the hydroconversion of coal by solvent treatment at elevated temperatures and pressure wherein an alcohol having an .alpha.-hydrogen atom, particularly a secondary alcohol such as isopropanol, is utilized as a hydrogen donor solvent. In a particular embodiment, a base capable of providing a catalytically effective amount of the corresponding alcoholate anion under the solvent treatment conditions is added to catalyze the alcohol-coal reaction.

  4. Electrospinning of Grooved Polystyrene Fibers: Effect of Solvent Systems

    Science.gov (United States)

    Liu, Wanjun; Huang, Chen; Jin, Xiangyu

    2015-05-01

    Secondary surface texture is of great significance to morphological variety and further expands the application areas of electrospun nanofibers. This paper presents the possibility of directly electrospinning grooved polystyrene (PS) fibers using both single and binary solvent systems. Solvents were classified as low boiling point solvent (LBPS): dichloromethane (DCM), acetone (ACE), and tetrahydrofuran (THF); high boiling point solvent (HBPS): N, N-dimethylformamide (DMF) and cyclohexanone (CYCo); and non-solvent (NS): 1-butanol (BuOH). By the systematic selection and combination of these solvents at given parameters, we found that single solvent systems produced non-grooved fibers. LBPS/DMF solvent systems resulted in fibers with different grooved textures, while LBPS/CYCo led to fibers with double grooved texture. Grooved fibers can also be fabricated from LBPS/LBPS, NS/LBPS, and NS/HBPS systems under specific conditions. The results indicated that the difference of evaporation rate (DER) between the two solvents played a key role in the formation of grooved texture. The formation of this unique texture should be attributed to three separate mechanisms, namely void-based elongation, wrinkle-based elongation, and collapsed jet-based elongation. Our findings can serve as guidelines for the preparation of ultrafine fibers with grooved secondary texture.

  5. Occupational solvent exposure and cognition

    Science.gov (United States)

    Sabbath, E.L.; Glymour, M.M.; Berr, C.; Singh-Manoux, A.; Zins, M.; Goldberg, M.

    2012-01-01

    Objective: Chronic occupational solvent exposure is associated with long-term cognitive deficits. Cognitive reserve may protect solvent-exposed workers from cognitive impairment. We tested whether the association between chronic solvent exposure and cognition varied by educational attainment, a proxy for cognitive reserve. Methods: Data were drawn from a prospective cohort of French national gas and electricity (GAZEL) employees (n = 4,134). Lifetime exposure to 4 solvent types (chlorinated solvents, petroleum solvents, benzene, and nonbenzene aromatic solvents) was assessed using a validated job-exposure matrix. Education was dichotomized at less than secondary school or below. Cognitive impairment was defined as scoring below the 25th percentile on the Digit Symbol Substitution Test at mean age 59 (SD 2.8; 88% of participants were retired at testing). Log-binomial regression was used to model risk ratios (RRs) for poor cognition as predicted by solvent exposure, stratified by education and adjusted for sociodemographic and behavioral factors. Results: Solvent exposure rates were higher among less-educated patients. Within this group, there was a dose-response relationship between lifetime exposure to each solvent type and RR for poor cognition (e.g., for high exposure to benzene, RR = 1.24, 95% confidence interval 1.09–1.41), with significant linear trends (p < 0.05) in 3 out of 4 solvent types. Recency of solvent exposure also predicted worse cognition among less-educated patients. Among those with secondary education or higher, there was no significant or near-significant relationship between any quantification of solvent exposure and cognition. Conclusions: Solvent exposure is associated with poor cognition only among less-educated individuals. Higher cognitive reserve in the more-educated group may explain this finding. PMID:22641403

  6. Solvent effects in chemistry

    CERN Document Server

    Buncel, Erwin

    2015-01-01

    This book introduces the concepts, theory and experimental knowledge concerning solvent effects on the rate and equilibrium of chemical reactions of all kinds.  It begins with basic thermodynamics and kinetics, building on this foundation to demonstrate how a more detailed understanding of these effects may be used to aid in determination of reaction mechanisms, and to aid in planning syntheses. Consideration is given to theoretical calculations (quantum chemistry, molecular dynamics, etc.), to statistical methods (chemometrics), and to modern day concerns such as ""green"" chemistry, where ut

  7. A novel digestion method based on a choline chloride–oxalic acid deep eutectic solvent for determining Cu, Fe, and Zn in fish samples

    Energy Technology Data Exchange (ETDEWEB)

    Habibi, Emadaldin [Department of Marine Chemistry, Faculty of Marine Science, Khorramshahr University of Marine Science and Technology, P.O. BOX 669, Khorramshahr (Iran, Islamic Republic of); Ghanemi, Kamal, E-mail: Kamal.ghanemi@kmsu.ac.ir [Department of Marine Chemistry, Faculty of Marine Science, Khorramshahr University of Marine Science and Technology, P.O. BOX 669, Khorramshahr (Iran, Islamic Republic of); Marine Science Research Institute, Khorramshahr University of Marine Science and Technology, Khorramshahr (Iran, Islamic Republic of); Fallah-Mehrjardi, Mehdi [Department of Marine Chemistry, Faculty of Marine Science, Khorramshahr University of Marine Science and Technology, P.O. BOX 669, Khorramshahr (Iran, Islamic Republic of); Marine Science Research Institute, Khorramshahr University of Marine Science and Technology, Khorramshahr (Iran, Islamic Republic of); Dadolahi-Sohrab, Ali [Department of Marine Environment, Faculty of marine natural resources, Khorramshahr University of Marine Science and Technology, Khorramshahr (Iran, Islamic Republic of)

    2013-01-31

    Highlights: ► A novel digestion method: lack of concentrated acids or oxidizing reagents. ► First report of using choline chloride–oxalic acid (ChCl–Ox) for digestion. ► Complete dissolution of biological samples in ChCl–Ox for solubilization metals. ► Extraction recoveries greater than 95%: validated by the fish protein CRM. ► Successfully applied in different fish tissues (Muscle, Liver, and Gills). -- Abstract: A novel and efficient digestion method based on choline chloride–oxalic acid (ChCl–Ox) deep eutectic solvent (DES) was developed for flame atomic absorption spectrometry (FAAS) determination of Cu, Zn, and Fe in biological fish samples. Key parameters that influence analyte recovery were investigated and optimized, using the fish protein certified reference material (CRM, DORM-3) throughout the procedure. In this method, 100 mg of the sample was dissolved in ChCl–Ox (1:2, molar ratio) at 100 °C for 45 min. Then, 5.0 mL HNO{sub 3} (1.0 M) was added. After centrifugation, the supernatant solution was filtered, diluted to a known volume, and analyzed by FAAS. Under optimized conditions, an excellent agreement between the obtained results and the certified values was observed, using Student's t-test (P = 0.05); the extraction recovery of the all elements was greater than 95.3%. The proposed method was successfully applied to the determination of analytes in different tissues (muscle, liver, and gills) having a broad concentration range in a marine fish sample. The reproducibility of the method was validated by analyzing all samples by our method in a different laboratory, using inductively coupled plasma optical emission spectrometry (ICP-OES). For comparison, a conventional acid digestion (CAD) method was also used for the determination of analytes in all studied samples. The simplicity of the proposed experimental procedure, high extraction efficiency, short analysis time, lack of concentrated acids and oxidizing agents, and the

  8. Solvent-free fluidic organic dye lasers.

    Science.gov (United States)

    Choi, Eun Young; Mager, Loic; Cham, Tran Thi; Dorkenoo, Kokou D; Fort, Alain; Wu, Jeong Weon; Barsella, Alberto; Ribierre, Jean-Charles

    2013-05-06

    We report on the demonstration of liquid organic dye lasers based on 9-(2-ethylhexyl)carbazole (EHCz), so-called liquid carbazole, doped with green- and red-emitting laser dyes. Both waveguide and Fabry-Perot type microcavity fluidic organic dye lasers were prepared by capillary action under solvent-free conditions. Cascade Förster-type energy transfer processes from liquid carbazole to laser dyes were employed to achieve color-variable amplified spontaneous emission and lasing. Overall, this study provides the first step towards the development of solvent-free fluidic organic semiconducting lasers and demonstrates a new kind of optoelectronic applications for liquid organic semiconductors.

  9. A combined interfacial and in-situ polymerization strategy to construct well-defined core-shell epoxy-containing SiO2-based microcapsules with high encapsulation loading, super thermal stability and nonpolar solvent tolerance

    Directory of Open Access Journals (Sweden)

    Yin Jia

    2016-10-01

    Full Text Available SiO2-based microcapsules containing hydrophobic molecules exhibited potential applications such as extrinsic self-healing, drug delivery, due to outstanding thermal and chemical stability of SiO2. However, to construct SiO2-based microcapsules with both high encapsulation loading and long-term structural stability is still a troublesome issue, limiting their further utilization. We herein design a single-batch route, a combined interfacial and in-situ polymerization strategy, to fabricate epoxy-containing SiO2-based microcapsules with both high encapsulation loading and long-term structural stability. The final SiO2-based microcapsules preserve high encapsulation loading of 85.7 wt% by controlling exclusively hydrolysis and condensed polymerization at oil/water interface in the initial interfacial polymerization step. In the subsequent in-situ polymerization step, the initial SiO2-based microcapsules as seeds could efficiently harvest SiO2 precursors and primary SiO2 particles to finely tune the SiO2 wall thickness, thereby enhancing long-term structural stability of the final SiO2-based microcapsules including high thermal stability with almost no any weight loss until 250°C, and strong tolerance against nonpolar solvents such as CCl4 with almost unchanged core-shell structure and unchanged core weight after immersing into strong solvents for up to 5 days. These SiO2-based microcapsules are extremely suited for processing them into anticorrosive coating in the presence of nonpolar solvents for self-healing application.

  10. Low density solvent-based dispersive liquid-liquid microextraction for the determination of synthetic antioxidants in beverages by high-performance liquid chromatography.

    Science.gov (United States)

    Çabuk, Hasan; Köktürk, Mustafa

    2013-01-01

    A simple and efficient method was established for the determination of synthetic antioxidants in beverages by using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with ultraviolet detection. Butylated hydroxy toluene, butylated hydroxy anisole, and tert-butylhydroquinone were the antioxidants evaluated. Experimental parameters including extraction solvent, dispersive solvent, pH of sample solution, salt concentration, and extraction time were optimized. Under optimal conditions, the extraction recoveries ranged from 53 to 96%. Good linearity was observed by the square of correlation coefficients ranging from 0.9975 to 0.9997. The relative standard deviations ranged from 1.0 to 5.2% for all of the analytes. Limits of detection ranged from 0.85 to 2.73 ng mL(-1). The method was successfully applied for determination of synthetic antioxidants in undiluted beverage samples with satisfactory recoveries.

  11. Solvent effects on optical excitations of poly para phenylene ethynylene studied by QM/MM simulations based on Many-Body Green's Functions Theory

    CERN Document Server

    Bagheri, Behnaz; Baumeier, Björn

    2016-01-01

    Electronic excitations in dilute solutions of poly para phenylene ethynylene (poly-PPE) are studied using a QM/MM approach combining many-body Green's functions theory within the $GW$ approximation and the Bethe-Salpeter equation with polarizable force field models. Oligomers up to a length of 7.5\\,nm (10 repeat units) functionalized with nonyl side chains are solvated in toluene and water, respectively. After equilibration using atomistic molecular dynamics (MD), the system is partitioned into a quantum region (backbone) embedded into a classical (side chains and solvent) environment. Optical absorption properties are calculated solving the coupled QM/MM system self-consistently and special attention is paid to the effects of solvents. The model allows to differentiate the influence of oligomer conformation induced by the solvation from electronic effects related to local electric fields and polarization. It is found that the electronic environment contributions are negligible compared to the conformational ...

  12. Preparation of Solvent-free & Water-basedλ-Cyhalothrin Liquid Formulations%无溶剂水基性高效氯氟氰菊酯液体剂型的研制

    Institute of Scientific and Technical Information of China (English)

    华乃震; 罗才宏; 曾鑫年

    2011-01-01

    [目的]俘油使用较多有机溶剂,而水基性剂型中微乳剂和可溶液剂使用较多极性溶剂作溶剂或助溶剂,在安全和环保性上受到人们质疑.论述水基性无溶剂液体剂型的提出、开发的依据及其优点.这种液体剂型不使用任何(极性和非极性)溶剂和植物油溶剂,研制出一种全新的水基性无溶剂2.5%高效氯氟氰菊酯透明液体剂型.[结果]经研制,其最佳配方:高效氯氟氰菊酯2.5%,乳化剂(烷基酚聚氧乙烯醚,烷基酚聚氧乙烯醚磷酸酯)12%~15%,助表面活性剂(丁醇)5%,防冻剂(丙二醇)2%,水余最.该配方样品为无色透明液体,经冷贮[(0±1)℃,7 d]和热贮[(54±2)℃,14 d]高效氯氟氰菊酯分解率小于2%.[结论]样品经测定各项指标符合有关要求,毒力测定结果与传统微乳剂相同.原料成本仅为同剂量乳油40%、传统微乳剂的72%、生物柴油作溶剂微乳剂的77%.%[Aims]EC uses much solvent, and water-based ME and SL use much solvent & flux (polar solvent), which receives question in the safety and the environmental protection.The water-based solvent-free liquid formulation proposal,development basis and merit were described in the article.This kind of liquid formulation does not use any (polar and nonpolar) solvent and vegetable oil solvent.One kind of brand-new water-based solvent-free λ-cyhalothrin 2.5% transparent liquid formulation was developed.[Results]The optimum ratio was as follow: λ-cyhalothrin 2.5%, emulsifier(alkylphenol ethoxylates, alkylphenol ethoxylates phosphate)12-15%, cosurfactant(butyl alcohol)5%, antifreeze(propylene glycol)2% and water remainder after research.This formula sample was colourless transparent liquid, after stored coldly [(0±1) ℃,7 d]and stored hotly [(54±2) ℃, 14 d], λ-cyhalothrin dissociation rate was less than 2%.[Conclusions]Each target of the sample meets the related requirement after test, and toxicity determination results showed that the

  13. Fabrication of porous ethyl cellulose microspheres based on the acetone-glycerin-water ternary system: Controlling porosity via the solvent-removal mode.

    Science.gov (United States)

    Murakami, Masahiro; Matsumoto, Akihiro; Watanabe, Chie; Kurumado, Yu; Takama, Masashi

    2015-08-01

    Porous ethyl cellulose (EC) microspheres were prepared from the acetone-glycerin-water ternary system using an oil/water (O/W)-type emulsion solvent extraction method. The O/ W type emulsion was prepared using acetone dissolved ethyl cellulose as an oil phase and aqueous glycerin as a water phase. The effects of the different solvent extraction modes on the porosity of the microspheres were investigated. The specific surface area of the porous EC microspheres was estimated by the gas adsorption method. When the solvent was extracted rapidly by mixing the emulsion with water instantaneously, porous EC microspheres with a maximum specific surface area of 40.7±2.1 m2/g were obtained. On the other hand, when water was added gradually to the emulsion, the specific surface area of the fabricated microspheres decreased rapidly with an increase in the infusion period, with the area being 25-45% of the maximum value. The results of an analysis of the ternary phase diagram of the system suggested that the penetration of water and glycerin from the continuous phase to the dispersed phase before solidification affected the porosity of the fabricated EC microspheres.

  14. Determination of polychlorinated biphenyls in fish: optimisation and validation of a method based on accelerated solvent extraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Ottonello, Giuliana; Ferrari, Angelo; Magi, Emanuele

    2014-01-01

    A simple and robust method for the determination of 18 polychlorinated biphenyls (PCBs) in fish was developed and validated. A mixture of acetone/n-hexane (1:1, v/v) was selected for accelerated solvent extraction (ASE). After the digestion of fat, the clean-up was carried out using solid phase extraction silica cartridges. Samples were analysed by GC-MS in selected ion monitoring (SIM) using three fragment ions for each congener (one quantifier and two qualifiers). PCB 155 and PCB 198 were employed as internal standards. The lowest limit of detection was observed for PCB 28 (0.4ng/g lipid weight). The accuracy of the method was verified by means of the Certified Reference Material EDF-2525 and good results in terms of linearity (R(2)>0.994) and recoveries (80-110%) were also achieved. Precision was evaluated by spiking blank samples at 4, 8 and 12ng/g. Relative standard deviation values for repeatability and reproducibility were lower than 8% and 16%, respectively. The method was applied to the determination of PCBs in 80 samples belonging to four Mediterranean fish species. The proposed procedure is particularly effective because it provides good recoveries with lowered extraction time and solvent consumption; in fact, the total time of extraction is about 12min per sample and, for the clean-up step, a total solvent volume of 13ml is required.

  15. CO2-Binding Organic Liquids Gas Capture with Polarity-Swing-Assisted Regeneration Full Technology Feasibility Study B1 - Solvent-based Systems

    Energy Technology Data Exchange (ETDEWEB)

    Heldebrant, David J

    2014-08-31

    PNNL, Fluor Corporation and Queens University (Kingston, ON) successfully completed a three year comprehensive study of the CO2BOL water-lean solvent platform with Polarity Swing Assisted Regeneration (PSAR). This study encompassed solvent synthesis, characterization, environmental toxicology, physical, thermodynamic and kinetic property measurements, Aspen Plus™ modeling and bench-scale testing of a candidate CO2BOL solvent molecule. Key Program Findings The key program findings are summarized as follows: • PSAR favorably reduced stripper duties and reboiler temperatures with little/no impact to absorption column • >90% CO2 capture was achievable at reasonable liquid-gas ratios in the absorber • High rich solvent viscosities (up to 600 cP) were successfully demonstrated in the bench-scale system. However, the projected impacts of high viscosity to capital cost and operational limits compromised the other levelized cost of electricity benefits. • Low thermal conductivity of organics significantly increased the required cross exchanger surface area, and potentially other heat exchange surfaces. • CO2BOL had low evaporative losses during bench-scale testing • There was no evidence of foaming during bench scale testing • Current CO2BOL formulation costs project to be $35/kg • Ecotoxicity (Water Daphnia) was comparable between CO2BOL and MEA (169.47 versus 103.63 mg/L) • Full dehydration of the flue gas was determined to not be economically feasible. However, modest refrigeration (13 MW for the 550 MW reference system) was determined to be potentially economically feasible, and still produce a water-lean condition for the CO2BOLs (5 wt% steady-state water loading). • CO2BOLs testing with 5 wt% water loading did not compromise anhydrous performance behavior, and showed actual enhancement of CO2 capture performance. • Mass transfer of CO2BOLs was not greatly impeded by viscosity • Facile separation of antisolvent from lean CO2BOL was

  16. Molecular structures of (3-aminopropyl)trialkoxysilane on hydroxylated barium titanate nanoparticle surfaces induced by different solvents and their effect on electrical properties of barium titanate based polymer nanocomposites

    Science.gov (United States)

    Fan, Yanyan; Wang, Guanyao; Huang, Xingyi; Bu, Jing; Sun, Xiaojin; Jiang, Pingkai

    2016-02-01

    Surface modification of nanoparticles by grafting silane coupling agents has proven to be a significant approach to improve the interfacial compatibility between inorganic filler and polymer matrix. However, the impact of grafted silane molecular structure after the nanoparticle surface modification, induced by the utilized solvents and the silane alkoxy groups, on the electrical properties of the corresponding nanocomposites, has been seldom investigated. Herein, the silanization on the surface of hydroxylated barium titanate (BT-OH) nanoparticles was introduced by using two kinds of trialkoxysilane, 3-aminopropyltriethoxysilane (AMEO) and 3-aminopropyltrimethoxysilane (AMMO), with different solvents (toluene and ethanol), respectively. Solid-state 13C, 29Si nuclear magnetic resonance (NMR) spectroscopy and high-resolution X-ray photoelectron spectroscopy (XPS) were employed to validate the structure differences of alkoxysilane attachment to the nanoparticles. The effect of alkoxysilane structure attached to the nanoparticle surface on the dielectric properties of the BT based poly(vinylidene fluoride) (PVDF) nanocomposites were investigated. The results reveal that the solvents used for BT nanoparticle surface modification exhibit a significant effect on the breakdown strength of the nanocomposites. Nevertheless, the alkoxy groups of silane show a marginal influence on the dielectric properties of the nanocomposites. These research results provide important insights into the fabrication of advanced polymer nanocomposites for dielectric applications.

  17. Organic solvent-free air-assisted liquid-liquid microextraction for optimized extraction of illegal azo-based dyes and their main metabolite from spices, cosmetics and human bio-fluid samples in one step.

    Science.gov (United States)

    Barfi, Behruz; Asghari, Alireza; Rajabi, Maryam; Sabzalian, Sedigheh

    2015-08-15

    Air-assisted liquid-liquid microextraction (AALLME) has unique capabilities to develop as an organic solvent-free and one-step microextraction method, applying ionic-liquids as extraction solvent and avoiding centrifugation step. Herein, a novel and simple eco-friendly method, termed one-step air-assisted liquid-liquid microextraction (OS-AALLME), was developed to extract some illegal azo-based dyes (including Sudan I to IV, and Orange G) from food and cosmetic products. A series of experiments were investigated to achieve the most favorable conditions (including extraction solvent: 77μL of 1-Hexyl-3-methylimidazolium hexafluorophosphate; sample pH 6.3, without salt addition; and extraction cycles: 25 during 100s of sonication) using a central composite design strategy. Under these conditions, limits of detection, linear dynamic ranges, enrichment factors and consumptive indices were in the range of 3.9-84.8ngmL(-1), 0.013-3.1μgmL(-1), 33-39, and 0.13-0.15, respectively. The results showed that -as well as its simplicity, fastness, and use of no hazardous disperser and extraction solvents- OS-AALLME is an enough sensitive and efficient method for the extraction of these dyes from complex matrices. After optimization and validation, OS-AALLME was applied to estimate the concentration of 1-amino-2-naphthol in human bio-fluids as a main reductive metabolite of selected dyes. Levels of 1-amino-2-naphthol in plasma and urinary excretion suggested that this compound may be used as a new potential biomarker of these dyes in human body.

  18. 基于轻质萃取剂的溶剂去乳化分散液-液微萃取-气相色谱法测定水样中多环芳烃%Low-density solvent-based solvent demulsification dispersive liquid-liquid microextraction combined with gas chromatography for determination of polycyclic aromatic hydrocarbons in water samples

    Institute of Scientific and Technical Information of China (English)

    祝本琼; 陈浩; 李胜清

    2012-01-01

    A novel method of low-density solvent-based solvent demulsification dispersive liquid-liquid microextraction (SD-DLLME) was developed for the determination of eight polycyclic aromatic hydrocarbons ( PAHs) in water samples by gas chromatography-flame ionization detection (GC-FID). Conventional DLLME methods usually employ organic solvents heavier than water as the extraction solvents and achieve the phase separation through centrifugation. On the contrary, in this proposed extraction procedure, a mixture of low-density extraction solvent (toluene) and dispersive solvent (acetone) was injected into the aqueous sample solution to form an emulsion. A demulsification solvent (acetonitrile) was then injected into the aqueous solution to break up the emulsion, which turned clear quickly and was separated into two layers. The upper layer (toluene) was collected and analyzed by GC. No centrifugation was required in this procedure. Factors affecting the extraction efficiency such as the type and volume of dispersive solvent, extraction solvent and de-emulsifier were investigated in detail. Under the optimized conditions, the proposed method provided a good linearity in the range of 20 - 500 μg/L (r2 = 0. 994 2 - 0. 999 9). The limits of detection (S/N = 3) were in the range of 0. 52 - 5. 11 μg/L. The relative standard deviations (RSDs) for the determination of 40 μg/LPAHs were in the range of 2. 2% - 13. 6% (n = 5). The proposed method is fast, efficient and convenient. It has been successfully applied to the determination of PAHs in natural water samples with the spiked recoveries of 80. 2% - 115. 1%.%以密度小于水的轻质溶剂为萃取剂,建立了无需离心步骤的溶剂去乳化分散液-液微萃取-气相色谱( SD-DLLME-GC)测定水样中多环芳烃的新方法.传统分散液-液微萃取技术一般采用密度大于水的有机溶剂为萃取剂,并需要通过离心步骤促进分相.而本方法以密度比水小的轻质溶剂

  19. Continuous flow analytical microsystems based on low-temperature co-fired ceramic technology. Integrated potentiometric detection based on solvent polymeric ion-selective electrodes.

    Science.gov (United States)

    Ibanez-Garcia, Nuria; Mercader, Manel Bautista; Mendes da Rocha, Zaira; Seabra, Carlos Antonio; Góngora-Rubio, Mario Ricardo; Chamarro, Julian Alonso

    2006-05-01

    In this paper, the low-temperature co-fired ceramics (LTCC) technology, which has been commonly used for electronic applications, is presented as a useful alternative to construct continuous flow analytical microsystems. This technology enables not only the fabrication of complex three-dimensional structures rapidly and at a realistic cost but also the integration of the elements needed to carry out a whole analytical process, such as pretreatment steps, mixers, and detection systems. In this work, a simple and general procedure for the integration of ion-selective electrodes based on liquid ion exchanger is proposed and illustrated by using ammonium- and nitrate-selective membranes. Additionally, a screen-printed reference electrode was easily incorporated into the microfluidic LTCC structure allowing a complete on-chip integration of the potentiometric detection. Analytical features of the proposed systems are presented.

  20. Copper-based energetic MOFs with 3-nitro-1H-1,2,4-triazole: solvent-dependent syntheses, structures and energetic performances.

    Science.gov (United States)

    Qu, Xiaoni; Zhai, Lianjie; Wang, Bozhou; Wei, Qing; Xie, Gang; Chen, Sanping; Gao, Shengli

    2016-11-01

    The persistent challenge in the field of energetic materials is how to synthesize energetic compounds with high density, high heat of detonation and outstanding detonation performance by gathering the maximum number of energetic groups in the smallest volume. The self-assembly of energetic groups with metal ions is crucially influenced by the solvent conditions. Here, the reaction of Cu(NO3)2·3H2O with 3-nitro-1H-1,2,4-triazole (Hntz) in aqueous ammonia under hydrothermal conditions via a self-assembly strategy yielded the Cu(i) energetic compound [Cu(ntz)]n (1). In order to further enhance the energetic property, an N3(-) anion was introduced into the system and two Cu(ii) energetic compounds, [Cu(ntz)(N3)(DMF)]n (2) and [Cu(ntz)(N3)(H2O)]n (3), were successfully synthesized under different solvent conditions. Structural analyses show that compound 1 features a compacted 3D structure framework and compounds 2-3 exhibit 1D butterfly-like chain structures. The experimental results reveal that 1 possesses attractive thermal stability up to 315.0 °C and 1-3 present excellent insensitivity. Importantly, the heat of detonation of compound 2 has been factually improved due to the abundant energetic bonds in the coordinated DMF molecules compared to 1 and lots of energies are taken away during the release of the coordinated solvent molecules in the low temperature range resulting in the obvious decreases in detonation pressure and detonation velocity for compounds 2-3, which further exemplifies that the subtle change of reaction conditions may have a crucial effect on the resultant detonation performance. In addition, the detonation performances of 1-3 calculated by both a simple method for metal-containing explosives developed by Pang et al. and the commercial program EXPLO5 v6.01, are discussed in detail.

  1. New Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H-ones Catalyzed by Benzotriazolium-Based Ionic Liquids under Solvent-Free Conditions

    Directory of Open Access Journals (Sweden)

    Zhiqing Liu

    2016-04-01

    Full Text Available An efficient synthesis of novel 3,4-dihydropyrimidin-2(1H-ones (DHPMs and their derivatives, using Brønsted acidic ionic liquid [C2O2BBTA][TFA] as a catalyst, from the condensation of aryl aldehyde, β-ketoester and urea was described. Reactions proceeded smoothly for 40 min under solvent-free conditions and gave the desirable products with good to excellent yields (up to 99%. The catalyst could be easily recycled and reused with similar efficacies for at least six cycles.

  2. ESES: Software for Eulerian solvent excluded surface.

    Science.gov (United States)

    Liu, Beibei; Wang, Bao; Zhao, Rundong; Tong, Yiying; Wei, Guo-Wei

    2017-03-15

    Solvent excluded surface (SES) is one of the most popular surface definitions in biophysics and molecular biology. In addition to its usage in biomolecular visualization, it has been widely used in implicit solvent models, in which SES is usually immersed in a Cartesian mesh. Therefore, it is important to construct SESs in the Eulerian representation for biophysical modeling and computation. This work describes a software package called Eulerian solvent excluded surface (ESES) for the generation of accurate SESs in Cartesian grids. ESES offers the description of the solvent and solute domains by specifying all the intersection points between the SES and the Cartesian grid lines. Additionally, the interface normal at each intersection point is evaluated. Furthermore, for a given biomolecule, the ESES software not only provides the whole surface area, but also partitions the surface area according to atomic types. Homology theory is utilized to detect topological features, such as loops and cavities, on the complex formed by the SES. The sizes of loops and cavities are measured based on persistent homology with an evolutionary partial differential equation-based filtration. ESES is extensively validated by surface visualization, electrostatic solvation free energy computation, surface area and volume calculations, and loop and cavity detection and their size estimation. We used the Amber PBSA test set in our electrostatic solvation energy, area, and volume validations. Our results are either calibrated by analytical values or compared with those from the MSMS software. © 2017 Wiley Periodicals, Inc.

  3. SOLVENT EXTRACTION OF URANIUM VALUES

    Science.gov (United States)

    Feder, H.M.; Ader, M.; Ross, L.E.

    1959-02-01

    A process is presented for extracting uranium salt from aqueous acidic solutions by organic solvent extraction. It consists in contacting the uranium bearing solution with a water immiscible dialkylacetamide having at least 8 carbon atoms in the molecule. Mentioned as a preferred extractant is dibutylacetamide. The organic solvent is usually used with a diluent such as kerosene or CCl/sub 4/.

  4. Hydrogen atom transfer from 1,n-alkanediamines to the cumyloxyl radical. Modulating C-H deactivation through acid-base interactions and solvent effects.

    Science.gov (United States)

    Milan, Michela; Salamone, Michela; Bietti, Massimo

    2014-06-20

    A time-resolved kinetic study on the effect of trifluoroacetic acid (TFA) on the hydrogen atom transfer (HAT) reactions from 1,n-alkanediamines (R2N(CH2)nNR2, R = H, CH3; n = 1-4), piperazine, and 1,4-dimethylpiperazine to the cumyloxyl radical (CumO(•)), has been carried out in MeCN and DMSO. Very strong deactivation of the α-C-H bonds has been observed following nitrogen protonation and the results obtained have been explained in terms of substrate basicity, of the distance between the two basic centers and of the solvent hydrogen bond acceptor ability. At [substrate] ≤ 1/2 [TFA] the substrates exist in the doubly protonated form HR2N(+)(CH2)nN(+)R2H, and no reaction with CumO(•) is observed. At 1/2 [TFA] [TFA], HAT occurs from the α-C-H bonds of R2N(CH2)nNR2, and the mesured kH values are very close to those obtained in the absence of TFA. Comparison between MeCN and DMSO clearly shows that in the monoprotonated diamines R2N(CH2)nN(+)R2H remote C-H deactivation can be modulated through solvent hydrogen bonding.

  5. The effects of different solvents and excitation wavelength on the photophysical properties of two novel Ir(III) complexes based on phenylcinnoline ligand.

    Science.gov (United States)

    Xu, Jing; Yang, Chaolong; Tong, Bihai; Zhang, Yunfei; Liang, Liyan; Lu, Mangeng

    2013-09-01

    Two novel cyclometalated iridium(III) complexes, Ir(pcl)2(pic) and Ir(pcl)2(fpic) (pcl: 3-phenylcinnoline, pic: picolinic acid, fpic: 5-fluoro-2-picolinic acid) were synthesized and characterized by FTIR, (1)H NMR spectroscopy, UV-vis, PL, and MALDI-TOF. These two Ir-complexes geometry were predicted using the Sparkle/PM6 model and suggested to a chemical environment of very low symmetry around the Ir ions (C 1). The PL spectrum of Ir(pcl)2(pic) and Ir(pcl)2(fpic) indicated that these complex belonged to red light emission, and maximum emission wavelength located at 647 and 641 nm, respectively. Most importantly, the effects of different solvents on their photoluminescent properties were detailed investigated. The results indicated that the polarity of solvent played an important role for their emission spectra. With introducing fluoro group to the pyridyl ring, the maximum emission wavelength of Ir(pcl)2(fpic) was blue shifted about 6 nm, and the quantum yield was slightly higher than that of Ir(pcl)2(pic). In addition, the thermal properties of these two Ir-complexes were measured by TGA, and results indicated that they had relative good thermal properties.

  6. Equation for Calculating the Concentration of Solvent in Air That Discriminates between Exposure and Non-exposure Based on Biomarker Concentrations in the Urine of Workers

    Directory of Open Access Journals (Sweden)

    Kondo,Yoshiro

    2006-12-01

    Full Text Available To develop a new method for evaluating the intensity of workers’ exposures to toluene alone or toluene in mixed solvents, regression equations were calculated between the concentrations of toluene to which workers were exposed and the concentrations of hippuric acid or toluene in workers’ urine samples taken at the end of their shifts. Thereafter, the discriminant exposure concentration of the solvents in air, which was the concentration considered to discriminate exposure from non-exposure within a fi xed level of error using fi ducial ranges of individual specimens (DEC-I or using confi dence ranges of regression equation (DEC-R, was measured by a scale. The devised equations were applied to calculate DEC-I or DEC-R accurately using the formulas expressing a regression line and its fi ducial ranges or confi dence ranges. The equations can calculate not only more precise values of DEC-I or DEC-R than can be measured by a scale, but can also calculate values corresponding to any level of error. Moreover, DEC-I and DEC-R can be defi ned by the equations. The concentration capable of discriminating TLV (threshold limit value exposure from non-TLV exposure was estimated using fi ducial ranges (DTL-I and then using confi dence ranges of the regression equation (DTL-R.

  7. Supramolecular solvent-based extraction coupled with vortex-mixing for determination of palladium and silver in water samples by flame atomic absorption spectrometry.

    Science.gov (United States)

    Meng, Lifen; Cheng, Jiaxi; Yang, Yaling

    2014-01-01

    A simple and practical extraction method of supramolecular solvents (SUPRAS) was developed for separation and enrichment of trace amounts of palladium (Pd) and silver (Ag) in water samples prior to flame atomic absorption spectrometry (FAAS) analysis. The SUPRAS selected was made up of an aqueous solution containing tetrahydrofuran and nonanoic acid. Pd and Ag reacted with diethyldithiocarbamate to form hydrophobic chelates, which were extracted into the vesicles of SUPRAS. Different parameters such as the concentration of chelating agent, sample pH, supramolecular solvent and the effect of foreign ions were studied. Under the optimal conditions, the linear ranges of Pd and Ag were from 10 to 1,000 μg/L. The relative recoveries of Pd and Ag in tap and river water samples at the spiking level of 10 ug/mL ranged from 90.8 to 116%. The relative standard deviations were 3.6-4.0% (n = 9), the limits of detection were 2.8 and 1.9 μg/L and the enrichment factors were 36 and 18 for Pd and Ag, respectively. The quantification limits were 3.2 and 2.4 μg/L. The method was successfully applied to the determination of Pd and Ag in water samples.

  8. Solvent effects on optical excitations of poly para phenylene ethynylene studied by QM/MM simulations based on many-body Green's functions theory

    Science.gov (United States)

    Bagheri, B.; Karttunen, M.; Baumeier, B.

    2016-07-01

    Electronic excitations in dilute solutions of poly para phenylene ethynylene (poly-PPE) are studied using a QM/MM approach combining many-body Green's functions theory within the GW approximation and the Bethe-Salpeter equation with polarizable force field models. Oligomers up to a length of 7.5 nm (10 repeat units) functionalized with nonyl side chains are solvated in toluene and water, respectively. After equilibration using atomistic molecular dynamics (MD), the system is partitioned into a quantum region (backbone) embedded into a classical (side chains and solvent) environment. Optical absorption properties are calculated solving the coupled QM/MM system self-consistently and special attention is paid to the effects of solvents. The model allows to differentiate the influence of oligomer conformation induced by the solvation from electronic effects related to local electric fields and polarization. It is found that the electronic environment contributions are negligible compared to the conformational dynamics of the conjugated PPE. An analysis of the electron-hole wave function reveals a sensitivity of energy and localization characteristics of the excited states to bends in the global conformation of the oligomer rather than to the relative of phenyl rings along the backbone.

  9. Selection and design of solvents

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    . With increasing interest on issues such as waste, sustainability, environmental impact and green chemistry, the selection and design of solvents have become important problems that need to be addressed during chemical product-process design and development. Systematic methods and tools suitable for selection...... and design of solvents will be presented together with application examples. The selection problem is defined as finding known chemicals that match the desired functions of a solvent for a specified set of applications. The design problem is defined as finding the molecular structure (or mixture of molecules......) that match the desired functions of a solvent for a specified set of applications. Use of organic chemicals and ionic liquids as solvents will be covered....

  10. Solvent degradation products in nuclear fuel processing solvents

    Energy Technology Data Exchange (ETDEWEB)

    Shook, H.E. Jr.

    1988-06-01

    The Savannah River Plant uses a modified Purex process to recover enriched uranium and separate fission products. This process uses 7.5% tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons for the solvent extraction of a nitric acid solution containing the materials to be separated. Periodic problems in product decontamination result from solvent degradation. A study to improve process efficiency has identified certain solvent degradation products and suggested mitigation measures. Undecanoic acid, lauric acid, and tridecanoic acid were tentatively identified as diluent degradation products in recycle solvent. These long-chain organic acids affect phase separation and lead to low decontamination factors. Solid phase extraction (SPE) was used to concentrate the organic acids in solvent prior to analysis by high performance liquid chromatography (HPLC). SPE and HPLC methods were optimized in this work for analysis of decanoic acid, undecanoic acid, and lauric acid in solvent. Accelerated solvent degradation studies with 7.5% TBP in normal paraffin hydrocarbons showed that long-chain organic acids and long-chain alkyl butyl phosphoric acids are formed by reactions with nitric acid. Degradation of both tributyl phosphate and hydrocarbon can be minimized with purified normal paraffin replacing the standard grade presently used. 12 refs., 1 fig., 3 tabs.

  11. Switchable Polarity Solvents: Are They Green?

    Science.gov (United States)

    Plaumann, Heinz

    2017-03-01

    Solvents play an incredibly important role in large scale chemical reactions. Switchable polarity solvents may prove to be a class of solvent that offers energy and material efficiencies greater than existing solvents. This paper examines such solvents and their potential in a variety of chemical reactions.

  12. Organic solvents in electromembrane extraction: recent insights

    DEFF Research Database (Denmark)

    Huang, Chuixiu; Gjelstad, Astrid; Pedersen-Bjergaard, Stig

    2016-01-01

    Electromembrane extraction (EME) was invented in 2006 as a miniaturized sample preparation technique for the separation of ionized species from aqueous samples. This concept has been investigated in different areas of analytical chemistry by different research groups worldwide since the introduct......Electromembrane extraction (EME) was invented in 2006 as a miniaturized sample preparation technique for the separation of ionized species from aqueous samples. This concept has been investigated in different areas of analytical chemistry by different research groups worldwide since...... the introduction. Under the influence of an electrical field, EME is based on electrokinetic migration of the analytes through a supported liquid membrane (SLM), which is an organic solvent immobilized in the pores of the polymeric membrane, and into the acceptor solution. Up to date, close to 150 research...... articles with focus on EME have been published. The current review summarizes the performance of EME with different organic solvents and discusses several criteria for efficient solvents in EME. In addition, the authors highlight their personal perspective about the most promising organic solvents for EME...

  13. Droplet Formation via Solvent Shifting in a Microfluidic Device

    CERN Document Server

    Hajian, Ramin

    2014-01-01

    Solvent shifting is a process in which a non-solvent is added to a solvent/solute mixture and extracts the solvent. The solvent and the non-solvent are miscible. Because of solution supersaturation a portion of the solute transforms to droplets. In this paper, based on this process, we present an investigation on droplet formation and their radial motion in a microfluidic device in which a jet is injected in a co-flowing liquid stream. Thanks to the laminar flow, the microfluidic setup enables studying diffusion mass transfer in radial direction and obtaining well-defined concentration distributions. Such profiles together with Ternary Phase Diagram (TPD) give detailed information about the conditions for droplet formation condition as well as their radial migration in the channel. The ternary system is composed of ethanol (solvent), de-ionized water (non-solvent) and divinyle benzene (solute). We employ analytical/numerical solutions of the diffusion equation to obtain concentration profiles of the component...

  14. Exploring the aryl esterase catalysis of paraoxonase-1 through solvent kinetic isotope effects and phosphonate-based isosteric analogues of the tetrahedral reaction intermediate.

    Science.gov (United States)

    Bavec, Aljoša; Knez, Damijan; Makovec, Tomaž; Stojan, Jure; Gobec, Stanislav; Goličnik, Marko

    2014-11-01

    Although a recent study of Debord et al. in Biochimie (2014; 97:72-77) described the thermodynamics of the catalysed hydrolysis of phenyl acetate by human paraoxonase-1, the mechanistic details along the reaction route of this enzyme remain unclear. Therefore, we briefly present the solvent kinetic isotope effects on the phenyl acetate esterase activity of paraoxonase-1 and its inhibition with the phenyl methylphosphonate anion, which is a stable isosteric analogue that mimics the high-energy tetrahedral intermediate on the hydroxide-promoted hydrolysis pathway. The data show normal isotope effects, while proton inventory analysis indicates that two protons contribute to the kinetic isotope effect. Coherently, moderate competitive inhibition with the phenyl methylphosphonate anion reveals that the rate-limiting transition state suboptimally resembles the tetrahedral intermediate. The implications of these findings can be attributed to two possible reaction mechanisms that might occur during the paraoxonase-1-catalysed hydrolysis of phenyl acetate.

  15. Probing solute-solvent interaction in 1-ethyl-3-methylimidazolium-based room temperature ionic liquids: A time-resolved fluorescence anisotropy study.

    Science.gov (United States)

    Das, Sudhir Kumar; Sarkar, Moloy

    2014-03-01

    Rotational diffusion of two organic solutes, coumarin153 (C153) and 4-aminophthalimide (AP) has been investigated in four ionic liquids (ILs), viz. 1-ethyl-3-methylimidazolium trifluoroacetate (EMIMTFA), 1-ethyl-3-methylimidazolium ethylsulfate (EMIMESU), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMTFB) and 1-ethyl-3-methylimidazolium tetracyanoborate (EMIMTCB), as a function of temperature. Between the two probes, AP can act as hydrogen-bond-donor to the solvents having hydrogen bond acceptor ability. The results indicate that the rotational dynamics of C153 is mainly governed by the viscosity of the medium. On the other hand, the rotational motion of AP is found to be significantly hindered in the ILs depending on the nature of anions of the ILs. Rotational coupling constant values for AP in the ILs follow the order TFA > ESU > TCB > TFB. The slower rotational motion of AP in these ILs has been attributed to the specific hydrogen bonding interaction between AP and anions of ILs.

  16. The influence of a solvent on the crystal morphology of RDX

    NARCIS (Netherlands)

    Horst, J.H. ter; Geertman, R.M.; Heijden, A.E.D.M. van der; Rosmalen, G.M. van

    1999-01-01

    A solvent can have a large influence on the crystal morphology. A molecular modeling technique based on the adsorption of solvent molecules on a crystal surface has been used to predict the influence of a solvent on the morphology of RDX. The predicted morphology has been compared with the experimen

  17. Program for Assisting the Replacement of Industrial Solvents PARIS III User’s Guide

    Science.gov (United States)

    PARIS III is a third generation Windows-based computer software to assist the design of less harmful solvent replacements by estimating values of the solvent properties that characterize the static, dynamic, performance, and environmental behavior of the original solvent mixture ...

  18. Handbook of organic solvent properties

    CERN Document Server

    Smallwood, Ian

    2012-01-01

    The properties of 72 of the most commonly used solvents are given, tabulated in the most convenient way, making this book a joy for industrial chemists to use as a desk reference. The properties covered are those which answer the basic questions of: Will it do the job? Will it harm the user? Will it pollute the air? Is it easy to handle? Will it pollute the water? Can it be recovered or incinerated? These are all factors that need to be considered at the early stages of choosing a solvent for a new product or process.A collection of the physical properties of most commonly used solvents, their

  19. The Solvent Selection framework: solvents for organic synthesis, separation processes and ionic-organic synthesis

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Sansonetti, Sascha; Abildskov, Jens;

    2012-01-01

    problems are presented: 1) solvent selection and design for organic synthesis, 2) solvent screening and design of solvent mixtures for pharmaceutical applications and 3) ionic liquids selection and design as solvents. The application of the framework is highlighted successfully through case studies...... focusing on solvent replacement problem in organic synthesis and solvent mixture design for ibuprofen respectively....

  20. A novel extraction method for β-carotene and other carotenoids in fruit juices using air-assisted, low-density solvent-based liquid-liquid microextraction and solidified floating organic droplets.

    Science.gov (United States)

    Sricharoen, Phitchan; Limchoowong, Nunticha; Techawongstien, Suchila; Chanthai, Saksit

    2016-07-15

    Green extraction using air-assisted, low-density solvent-based liquid-liquid microextraction and solidified floating organic droplets (AA-LDS-LLME-SFOD) prior to spectrophotometry was successfully applied for quantitation of carotenoids in fruit juices. Under optimal conditions, β-carotene could be quantified with a linear response up to a concentration of 60 μg mL(-1). The procedure was performed in a microcentrifuge tube with 40 μL of 1-dodecanol as the extraction solvent and a 1.0 mL juice sample containing 8% NaCl under seven extraction cycles of air pumping by syringe. This method was validated based on linearity (0.2-30 μg mL(-1), R(2) 0.998), limit of detection (0.04 μg mL(-1)) and limit of quantification (0.13 μg mL(-1)). The precision, expressed as the relative standard deviation (RSD) of the calibration curve slope (n=12), for inter-day and intra-day analysis was 4.85% and 7.92%, respectively. Recovery of β-carotene was in the range of 93.6-101.5%. The newly proposed method is simple, rapid and environmentally friendly, particularly as a useful screening test for food analysis.

  1. Hansen Cleaning Solvent Research Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Environmental regulation will force current baseline  precision cleaning solvent (AK-225) to be phased out starting 2015. We plan to develop  a new...

  2. Applied biotransformations in green solvents.

    Science.gov (United States)

    Hernáiz, María J; Alcántara, Andrés R; García, José I; Sinisterra, José V

    2010-08-16

    The definite interest in implementing sustainable industrial technologies has impelled the use of biocatalysts (enzymes or cells), leading to high chemo-, regio- and stereoselectivities under mild conditions. As usual substrates are not soluble in water, the employ of organic solvents is mandatory. We will focus on different attempts to combine the valuable properties of green solvents with the advantages of using biocatalysts for developing cleaner synthetic processes.

  3. Determination of fungicides in fruit juice by ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of floating organic solvent droplets followed by high performance liquid chromatography.

    Science.gov (United States)

    Fan, Run-Zhen; Liu, Congyun; Jiang, Wenqing; Wang, Xiaonan; Liu, Fengmao

    2014-01-01

    Ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) based on solidification of the floating organic solvent droplets (SFO) combined with HPLC was used for determination of five fungicides in fruit juice samples. 1-Dodecanol, which has a low density and low toxicity, was used as the extraction solvent in UA-DLLME. The solidification of floating organic droplets facilitates the transfer of analytes from the aqueous phase to the organic phase. This method was easy, quick, inexpensive, precise, and linear over a wide range. Under the optimized conditions, the enrichment factors for a 5 mL fruit juice sample were 25 to 56, and the LODs for the five fungicides ranged from 5 to 50 microg/L. The average recoveries ranged from 71.8 to 118.2% with RSDs of 0.9 to 13.9%. Application of the DLLME-SFO technique allows successful separation and preconcentration of the fungicides at a low concentration level in fruit juice samples.

  4. Method for Selection of Solvents for Promotion of Organic Reactions

    DEFF Research Database (Denmark)

    Gani, Rafiqul; Jiménez-González, Concepción; Constable, David J.C.

    2005-01-01

    A method to select appropriate green solvents for the promotion of a class of organic reactions has been developed. The method combines knowledge from industrial practice and physical insights with computer-aided property estimation tools for selection/design of solvents. In particular, it employs...... is to produce, for a given reaction, a short list of chemicals that could be considered as potential solvents, to evaluate their performance in the reacting system, and, based on this, to rank them according to a scoring system. Several examples of application are given to illustrate the main features and steps...

  5. Preparation of methacrylic acid copolymer S nano-fibers using a solvent-based electrospinning method and their application in pharmaceutical formulations.

    Science.gov (United States)

    Hamori, Mami; Shimizu, Yuki; Yoshida, Kaori; Fukushima, Keizo; Sugioka, Nobuyuki; Nishimura, Asako; Naruhashi, Kazumasa; Shibata, Nobuhito

    2015-01-01

    In this study, we applied an electrospinning (ES) method, which is mainly employed in the textile industry, to the field of pharmaceuticals. We developed and modified an ES instrument and then utilized it to produce methacrylic acid copolymer S (MAC) nano-fibers to prepare tablets. By attaching a conductor rod made from stainless steel to the central part of the nano-fiber-collection plate of the ES apparatus, a MAC nano-fiber sheet could be produced effectively. In addition, we studied various operating conditions for this new ES method, including needle gauge, voltage between the electrodes, distance between the needle and nano-fiber-collection plate and the flow rate of MAC polymer solution, but these had no significant effect on the diameter of MAC nano-fibers. On the other hand, the viscosity (concentration) of MAC polymer solution and permittivity of solvent used to dilute MAC were closely related to the mean diameter of the nano-fibers. Tableting of MAC nano-fibers was performed using a tableting machine without lubricants, and addition of Tween 20 to the tablets enabled regulation of the release profile of a water-soluble drug. The modified ES method reported here is a useful technique for the controlled-release of drugs and has wide-ranging potential for pharmaceutical applications.

  6. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    Science.gov (United States)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  7. Functionalization of graphene using deep eutectic solvents

    Science.gov (United States)

    Hayyan, Maan; Abo-Hamad, Ali; AlSaadi, Mohammed AbdulHakim; Hashim, Mohd Ali

    2015-08-01

    Deep eutectic solvents (DESs) have received attention in various applications because of their distinctive properties. In this work, DESs were used as functionalizing agents for graphene due to their potential to introduce new functional groups and cause other surface modifications. Eighteen different types of ammonium- and phosphonium-salt-based DESs were prepared and characterized by FTIR. The graphene was characterized by FTIR, STA, Raman spectroscopy, XRD, SEM, and TEM. Additional experiments were performed to study the dispersion behavior of the functionalized graphene in different solvents. The DESs exhibited both reduction and functionalization effects on DES-treated graphene. Dispersion stability was investigated and then characterized by UV-vis spectroscopy and zeta potential. DES-modified graphene can be used in many applications, such as drug delivery, wastewater treatment, catalysts, composite materials, nanofluids, and biosensors. To the best of our knowledge, this is the first investigation on the use of DESs for graphene functionalization.

  8. Formation of Embedded Microstructures by Thermal Activated Solvent Bonding

    CERN Document Server

    Ng, S H; Wang, Z F; Lu, A C W; Rodriguez, I; De Rooij, N

    2008-01-01

    We present a thermal activated solvent bonding technique for the formation of embedded microstrucutres in polymer. It is based on the temperature dependent solubility of polymer in a liquid that is not a solvent at room temperature. With thermal activation, the liquid is transformed into a solvent of the polymer, creating a bonding capability through segmental or chain interdiffusion at the bonding interface. The technique has advantages over the more commonly used thermal bonding due to its much lower operation temperature (30 degrees C lower than the material's Tg), lower load, as well as shorter time. Lap shear test indicated bonding shear strength of up to 2.9 MPa. Leak test based on the bubble emission technique showed that the bonded microfluidic device can withstand at least 6 bars (87 psi) of internal pressure (gauge) in the microchannel. This technique can be applied to other systems of polymer and solvent.

  9. Self-healing Microencapsulation of Biomacromolecules without Organic Solvents**

    OpenAIRE

    Reinhold, Samuel E.; Desai, Kashappa-Goud H.; Zhang, Li; Olsen, Karl F.; Schwendeman, Steven P.

    2012-01-01

    Microencapsulation of biomacromolecules in PLGA is routinely performed with organic solvent through multiple complex steps deleterious to the biomacromolecule. The new self-healing based PLGA microencapsulation obviates micronization- and organic solvent-induced protein damage, provides very high encapsulation efficiency, exhibit stabilization and slow release of labile tetanus protein antigen, and provides long-term testosterone suppression in rats following a single injection of encapsulate...

  10. Handbook of green chemistry, green solvents, supercritical solvents

    CERN Document Server

    Anastas, Paul T; Jessop, Philip G

    2014-01-01

    Green Chemistry is a vitally important subject area in a world where being as green and environmentally sound as possible is no longer a luxury but a necessity. Its applications include the design of chemical products and processes that help to reduce or eliminate the use and generation of hazardous substances. The Handbook of Green Chemistry comprises 12 volumes, split into subject-specific sets as follows: Set I: Green Catalysis Set II: Green Solvents Volume 4: Supercritical Solvents Volume 5: Reactions in Water Volume 6: Ionic Liquids

  11. Efficient extraction and preparative separation of four main isoflavonoids from Dalbergia odorifera T. Chen leaves by deep eutectic solvents-based negative pressure cavitation extraction followed by macroporous resin column chromatography.

    Science.gov (United States)

    Li, Lu; Liu, Ju-Zhao; Luo, Meng; Wang, Wei; Huang, Yu-Yan; Efferth, Thomas; Wang, Hui-Mei; Fu, Yu-Jie

    2016-10-15

    In this study, green and efficient deep eutectic solvent-based negative pressure cavitation-assisted extraction (DES-NPCE) followed by macroporous resin column chromatography was developed to extract and separate four main isoflavonoids, i.e. prunetin, tectorigenin, genistein and biochanin A from Dalbergia odorifera T. Chen leaves. The extraction procedure was optimized systematically by single-factor experiments and a Box-Behnken experimental design combined with response surface methodology. The maximum extraction yields of prunetin, tectorigenin, genistein and biochanin A reached 1.204, 1.057, 0.911 and 2.448mg/g dry weight, respectively. Moreover, the direct enrichment and separation of four isoflavonoids in DES extraction solution was successfully achieved by macroporous resin AB-8 with recovery yields of more than 80%. The present study provides a convenient and efficient method for the green extraction and preparative separation of active compounds from plants.

  12. New observation on a class of old reactions:Chemoselectivity for the solvent-free reaction of aromatic aldehydes with alkylketones catalyzed by a double-component inorganic base system

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Solvent-free reactions of aromatic aldehydes with three representative ketones,including acetophenone,acetone and cyclohexanone,have been examined under the catalysis of a low-cost inorganic base system consisting of NaOH and K2CO3.It was found that the chemoselectivity of the reactions is in close relationship with the composition of the reactants and the doublecomponent catalyst.Under the optimized experimental conditions,1,2,3,4,5-pentasubstituted cyclohexanols,α,β-unsaturated ketones and Claisen-Schmidt bicondensation products were obtained in high yields.Two Kostanecki’s triketones were separated,The composition and structure were affirmed by X-ray crystallographic analysis.

  13. Cross-aldol Condensation of Cycloalkanones and Aromatic Aldehydes in the Presence of Nanoporous Silica-based Sulfonic Acid (SiO2-Pr-SO3H) under Solvent Free Conditions

    Institute of Scientific and Technical Information of China (English)

    MOHAMMADI ZIARANI Ghodsi; BADIEI Alireza; ABBASI Alireza; FARAHANI Zahra

    2009-01-01

    The aromatic aldehydes underwent cross aldol condensation with cycloalkanones in the presence of a catalytic amount of nanoporous silica-based sulfonic acid (SiO2-Pr-SO3H) under solvent-free conditions to afford the corresponding a,a'-bis(substituted benzylidene)cycloalkanones in excellent yields with short reaction time without any side reactions.This method is very general,simple and environmentally friendly in contrast with other existing methods.SiO2-Pr-SO3H was proved to be an efficient heterogeneous solid acid catalyst,which could be easily handled and removed from the reaction mixture by simple filtration,and also recovered and reused without loss of reactivity.

  14. Multiple sclerosis and organic solvents

    DEFF Research Database (Denmark)

    Mortensen, J T; Brønnum-Hansen, Henrik; Rasmussen, K

    1998-01-01

    We investigated a possible causal relation between exposure to organic solvents in Danish workers (housepainters, typographers/printers, carpenters/cabinetmakers) and onset of multiple sclerosis. Data on men included in the Danish Multiple Sclerosis Register (3,241 men) were linked with data from......, and butchers. Over a follow-up period of 20 years, we observed no increase in the incidence of multiple sclerosis among men presumed to be exposed to organic solvents. It was not possible to obtain data on potential confounders, and the study design has some potential for selection bias. Nevertheless......, the study does not support existing hypotheses regarding an association between occupational exposure to organic solvents and multiple sclerosis....

  15. Solvent extraction of Southern US tar sands

    Energy Technology Data Exchange (ETDEWEB)

    Penney, W.R.

    1990-01-01

    The Department of Chemical Engineering at the University of Arkansas, in association with Diversified Petroleum Recovery, Inc. (DPR) of Little Rock, Arkansas, has been developing a solvent extraction process for the recovery of bitumen from tar sands for the past five years. The unique feature of the process is that the bitumen is recovered from the solvent by contacting with a co-solvent, which causes the bitumen to precipitate. The overall purpose of this project is to study both the technical and economic feasibility of applying this technology for recovery of bitumen from tar sands by (1) investigating the socioeconmic factors which affect (a) plant siting and (b) the market value of recovered bitumen; (2) operating a process demonstration unit at the rate of 1 lb/hr recovered bitumen while producing clean sand and recyclable solvents; and (3) determine the economic conditions which will make a bitumen recovery project economical. DPR has analyzed the historical trends of domestic production, consumption, discoveries and reserves of crude oil. They have started an investigation of the volatility in the price of crude oil and of gasoline prices and of the differential between gasoline and crude oil. DPR continues to analyze the geographical movement and demand for asphalt products. Utah does not appear economically attractive as a site for a bitumen from tar sands asphalt plant. Oklahoma sites are now being studied. This report also contains the quarterly progress report from a University of Nevada study to determine bitumen composition, oxygen uptake rates, and viscosities of Alabama and Utah bitumens. Both reports have been indexed separately for inclusion on the data base.

  16. Scenarios Evaluation Tool for Chlorinated Solvent MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, Karen; Michael J. Truex; Charles J. Newell; Brian Looney

    2007-02-28

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  17. Solvent sorting in (mixed solvent + electrolyte) systems: Time-resolved fluorescence measurements and theory

    Indian Academy of Sciences (India)

    Harun Al Rasidgazi; Hemant K Kashyap; Ranjit Biswas

    2015-01-01

    In this manuscriptwe explore electrolyte-induced modification of preferential solvation of a dipolar solute dissolved in a binary mixture of polar solvents. Composition dependence of solvation characteristics at a fixed electrolyte concentration has been followed. Binary mixtures of two different polarities have been employed to understand the competition between solute-ion and solute-solvent interactions. Time-resolved fluorescence Stokes shift and anisotropy have been measured for coumarin 153 (C153) in moderately polar (ethyl acetate + 1-propanol) and strongly polar (acetonitrile + propylene carbonate) binary mixtures at various mixture compositions, and in the corresponding 1.0M solutions of LiClO4. Both the mixtures show red shifts in C153 absorption and fluorescence emission upon increase of mole fraction of the less polar solvent component in presence of the electrolyte. In addition, measured average solvation times become slower and rotation times faster for the above change in the mixture composition. A semi-molecular theory based on solution density fluctuations has been developed and found to successfully capture the essential features of the measured Stokes shift dynamics of these complex multi-component mixtures. Dynamic anisotropy results have been analyzed by using both Stokes-Einstein-Debye (SED) and Dote-Kivelson-Schwartz (DKS) theories. The importance of local solvent structure around the dissolved solute has been stressed.

  18. Recent Advances in Anhydrous Solvents for CO2 Capture: Ionic Liquids, Switchable Solvents, and Nanoparticle Organic Hybrid Materials

    Directory of Open Access Journals (Sweden)

    YOUNGJUNE ePARK

    2015-10-01

    Full Text Available CO2 capture by amine scrubbing, which has a high CO2 capture capacity and a rapid reaction rate, is the most employed and investigated approach to date. There are a number of recent large-scale demonstrations including the Boundary Dam Carbon Capture Project by SaskPower in Canada that have reported successful implementations of aqueous amine solvent in CO2 capture from flue gases. The findings from these demonstrations will significantly advance the field of CO2 capture in the coming years. While the latest efforts in aqueous amine solvents are exciting and promising, there are still several drawbacks to amine-based CO2 capture solvents including high volatility and corrosiveness of the amine solutions, as well as the high parasitic energy penalty during the solvent regeneration step. Thus, in a parallel effort, alternative CO2 capture solvents, which are often anhydrous, have been developed as the third-generation CO2 capture solvents. These novel classes of liquid materials include: Ionic Liquids (ILs, CO2-triggered switchable solvents (i.e., CO2 Binding Organic Liquids (CO2BOLs, Reversible Ionic Liquids (RevILs, and Nanoparticle Organic Hybrid Materials (NOHMs. This paper provides a review of these various anhydrous solvents and their potential for CO2 capture. Particular attention is given to the mechanisms of CO2 absorption in these solvents, their regeneration and their processability – especially taking into account their viscosity. While not intended to provide a complete coverage of the existing literature, this review aims at pointing the major findings reported for these new classes of CO2 capture media.

  19. Universal iso-density polarizable continuum model for molecular solvents

    CERN Document Server

    Gunceler, Deniz

    2014-01-01

    Implicit electron-density solvation models based on joint density-functional theory offer a computationally efficient solution to the problem of calculating thermodynamic quantities of solvated systems from first-principles quantum mechanics. However, despite much recent interest in such models, to date the applicability of such models to non-aqueous solvents has been limited because the determination of the model parameters requires fitting to a large database of experimental solvation energies for each new solvent considered. This work presents an alternate approach which allows development of new solvation models for a large class of protic and aprotic solvents from only simple, single-molecule ab initio calculations and readily available bulk thermodynamic data. We find that this model is accurate to nearly 1.7 kcal/mol even for solvents outside our development set.

  20. Computer-aided tool for solvent selection in pharmaceutical processes: Solvent swap

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; K. Tula, Anjan; Gernaey, Krist V.;

    In the pharmaceutical processes, solvents have a multipurpose role since different solvents can be used in different stages (such as chemical reactions, separations and purification) in the multistage active pharmaceutical ingredients (APIs) production process. The solvent swap and selection task...

  1. Improved Purex solvent scrubbing methods

    Energy Technology Data Exchange (ETDEWEB)

    Mailen, J.C.; Tallent, O.K.

    1984-01-01

    Studies of hydrazine and hydroxylamine salts as solvent scrubbing agents that can be decomposed into gases are summarized. Results from testing of countercurrent scrubbers and solid sorber columns that produce lesser amounts of permanent salts are reported. The status of studies of the acid-degradation of paraffin diluent and the options for removal of long-chain organic acids is given.

  2. Which solvent for olfactory testing?

    Science.gov (United States)

    Philpott, C M; Goodenough, P C; Wolstenholme, C R; Murty, G E

    2004-12-01

    The physical properties of any carrier can deteriorate over time and thus alter the results in any olfactory test. The aim of this study was to evaluate clinically potential solvents as a clean odourless carrier for olfactory testing. Sweet almond oil, pure coconut oil, pure peach kernel oil, dipropylene glycol, monopropylene glycol, mineral oil and silicone oil were studied. The experimentation was conducted in two parts. First, an olfactory device was used to conduct air through the solvents on a weekly basis using a cohort of six volunteers to assess the perceived odour of each solvent at weekly intervals. Secondly a cross-reference test was performed using small bottled solutions of phenylethyl-alcohol and 1-butanol in 10-fold dilutions to compare any perceived difference in concentrations over a period of 8 weeks. We concluded that mineral oil is the most suitable carrier for the purpose of olfactory testing, possessing many desirable characteristics of an olfactory solvent, and that silicone oil may provide a suitable alternative for odorants with which it is miscible.

  3. Method for analyzing solvent extracted sponge core

    Energy Technology Data Exchange (ETDEWEB)

    Ellington, W.E.; Calkin, C.L.

    1988-11-22

    For use in solvent extracted sponge core measurements of the oil saturation of earth formations, a method is described for quantifying the volume of oil in the fluids resulting from such extraction. The method consists of: (a) separating the solvent/oil mixture from the water in the extracted fluids, (b) distilling at least a portion of the solvent from the solvent/oil mixture substantially without co-distillation or loss of the light hydrocarbons in the mixture, (c) determining the volume contribution of the solvent remaining in the mixture, and (d) determining the volume of oil removed from the sponge by substracting the determined remaining solvent volume.

  4. Anthracene/phenothiazine π-conjugated sensitizers for dye-sensitized solar cells using redox mediator in organic and water-based solvents.

    Science.gov (United States)

    Lin, Ryan Yeh-Yung; Chuang, Tzu-Man; Wu, Feng-Ling; Chen, Pei-Yu; Chu, Te-Chun; Ni, Jen-Shyang; Fan, Miao-Syuan; Lo, Yih-Hsing; Ho, Kuo-Chuan; Lin, Jiann T

    2015-01-01

    Metal-free dyes (MD1 to MD5) containing an anthracene/phenothiazine unit in the spacer have been synthesized. The conversion efficiency (7.13 %) of the dye-sensitized solar cell using MD3 as the sensitizer reached approximately 85 % of the N719-based standard cell (8.47 %). The cell efficiency (8.42 %) of MD3-based dye-sensitized solar cells (DSSCs) with addition of chenodeoxycholic acid is comparable with that of N719-based standard cell. The MD3 water-based DSSCs using a dual-TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl)/iodide electrolyte exhibited very promising cell performance of 4.96 % with an excellent Voc of 0.77 V.

  5. Unified description of solvent effects in the helix-coil transition.

    Science.gov (United States)

    Badasyan, Artem; Tonoyan, Shushanik A; Giacometti, Achille; Podgornik, Rudolf; Parsegian, V Adrian; Mamasakhlisov, Yevgeni Sh; Morozov, Vladimir F

    2014-02-01

    We analyze the problem of the helix-coil transition in explicit solvents analytically by using spin-based models incorporating two different mechanisms of solvent action: explicit solvent action through the formation of solvent-polymer hydrogen bonds that can compete with the intrinsic intra-polymer hydrogen bonded configurations (competing interactions) and implicit solvent action, where the solvent-polymer interactions tune biopolymer configurations by changing the activity of the solvent (non-competing interactions). The overall spin Hamiltonian is comprised of three terms: the background in vacuo Hamiltonian of the "Generalized Model of Polypeptide Chain" type and two additive terms that account for the two above mechanisms of solvent action. We show that on this level the solvent degrees of freedom can be explicitly and exactly traced over, the ensuing effective partition function combining all the solvent effects in a unified framework. In this way we are able to address helix-coil transitions for polypeptides, proteins, and DNA, with different buffers and different external constraints. Our spin-based effective Hamiltonian is applicable for treatment of such diverse phenomena as cold denaturation, effects of osmotic pressure on the cold and warm denaturation, complicated temperature dependence of the hydrophobic effect as well as providing a conceptual base for understanding the behavior of intrinsically disordered proteins and their analogues.

  6. Determining an Efficient Solvent Extraction Parameters for Re-Refining of Waste Lubricating Oils

    Directory of Open Access Journals (Sweden)

    Hassan Ali Durrani

    2012-04-01

    Full Text Available Re-refining of vehicle waste lubricating oil by solvent extraction is one of the efficient and cheapest methods. Three extracting solvents MEK (Methyl-Ethyl-Ketone, 1-butanol, 2-propanol were determined experimentally for their performance based on the parameters i.e. solvent type, solvent oil ratio and extraction temperature. From the experimental results it was observed the MEK performance was highest based on the lowest oil percent losses and highest sludge removal. Further, when temperature of extraction increased the oil losses percent also decreased. This is due to the solvent ability that dissolves the base oil in waste lubricating oil and determines the best SOR (Solvent Oil Ratio and extraction temperatures.

  7. Novel electrolytes for Li{sub 4}Ti{sub 5}O{sub 12}-based high power lithium ion batteries with nitrile solvents

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qing; Pechy, Peter; Zakeeruddin, Shaik M.; Graetzel, Michael [Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, CH-1015 Lausanne (Switzerland); Exnar, Ivan [HPL, PSE-B, CH-1015 Lausanne (Switzerland)

    2005-08-26

    With the aim of improving the rate capability and the safety of nanocrystalline Li{sub 4}Ti{sub 5}O{sub 12}-based high power lithium ion batteries, two high boiling point nitrile-based electrolytes namely, 3-ethoxypropionitrile (CH{sub 3}CH{sub 2}OCH{sub 2}CH{sub 2}CN, EPN)/1M LiTFSI and 3-(2,2,2-trifluoro)ethoxypropionitrile (CF{sub 3}CH{sub 2}OCH{sub 2}CH{sub 2}CN, FEPN)/1M LiTFSI, are investigated in this study. Both electrolytes demonstrated superior rate capability to that of EC+DMC-based electrolyte, owing to the fast interfacial charge transfer process of lithium insertion/extraction. (author)

  8. Supercritical Fluid Extraction versus Traditional Solvent Extraction of Caffeine from Tea Leaves: A Laboratory-Based Case Study for an Organic Chemistry Course

    Science.gov (United States)

    Schaber, Peter M.; Larkin, Judith E.; Pines, Harvey A.; Berchou, Kelly; Wierchowski, Elizabeth; Marconi, Andrew; Suriani, Allison

    2012-01-01

    In this case-based laboratory, an instrument sales person attempts to convince an analysis laboratory of the virtues of supercritical fluid extraction (SFE). The sales person deals directly with the laboratory technicians who will make the decision. Arrangements are made to have SFE instrumentation brought into the laboratory for a comparative…

  9. The first TDDFT and MCD studies of free base triarylcorroles: a closer look into solvent-dependent UV-visible absorption.

    Science.gov (United States)

    Ziegler, Christopher J; Sabin, Jared R; Geier, G Richard; Nemykin, Victor N

    2012-05-16

    Absorption spectra of several free base triarylcorroles were investigated by MCD spectroscopy. The MCD spectra exhibit unusual sign-reverse (positive-to-negative intensities in ascending energy) features in the Soret- and Q-type band regions, suggesting a rare ΔHOMO < ΔLUMO relationship between π and π* MOs in the corrole core.

  10. Behavioral evaluation of workers exposed to mixtures of organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Maizlish, N.A.; Langolf, G.D.; Whitehead, L.W.; Fine, L.J.; Albers, J.W.; Goldberg, J.; Smith, P.

    1985-09-01

    Reports from Scandinavia have suggested behavioral impairment among long term workers exposed to solvents below regulatory standards. A cross sectional study of behavioral performance was conducted among printers and spray painters exposed to mixtures of organic solvents to replicate the Scandinavian studies and to examine dose-response relationships. Eligible subjects consisted of 640 hourly workers from four midwestern United States companies. Of these, 269 responded to requests to participate and 240 were selected for study based on restrictions for age, sex, education, and other potentially confounding variables. The subjects tested had been employed on average for six years. Each subject completed an occupational history, underwent a medical examination, and completed a battery of behavioural tests. These included the Fitts law psychomotor task, the Stroop color-word test, the Sternberg short term memory scanning test, the short term memory span test, and the continuous recognition memory test. Solvent exposure for each subject was defined as an exposed or non-exposed category based on a plant industrial hygiene walk-through and the concentration of solvents based on an analysis of full shift personal air samples by gas chromatography. The first definition was used to maintain consistency with Scandinavian studies, but the second was considered to be more accurate. The average full shift solvent concentration was 302 ppm for the printing plant workers and 6-13 ppm for the workers at other plants. Isopropanol and hexane were the major components, compared with toluene in Scandinavian studies.

  11. Versatile high pressure CO2 capture test facility for solvent development: set-up for gaining accurate knowledge of solvent systems

    NARCIS (Netherlands)

    Runstraat, A. van de; Goetheer, E.L.V.; Giling, E.J.M.

    2013-01-01

    Solvent based technology is the state of the art method for the removal of CO2 from natural gas or from shifted syn gas (pre-combustion CO2-capture). In this typical upgrading technology, CO2 is removed from the gas mixture by absorption using physical or reactive solvents. There is an increasing tr

  12. Third generation capture system: precipitating amino acid solvent systems

    NARCIS (Netherlands)

    Sanchez Fernandez, E.; Misiak, K.; Ham, L. van der; Goetheer, E.L.V.

    2013-01-01

    This work summarises the results of the design of novel separation processes for CO2 removal from flue gas based on precipitating amino acid solvents. The processes here described (DECAB, DECAB Plus and pH-swing) use a combination of enhanced CO2 absorption (based on the Le Chatelier’s principle) an

  13. Novel homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff bases: Synthesis, characterization, solvent-extraction and catalase-like activity studies

    Energy Technology Data Exchange (ETDEWEB)

    Dede, Buelent [Sueleyman Demirel University, Department of Chemistry, Isparta, 32260 (Turkey)], E-mail: dbulent@fef.sdu.edu.tr; Karipcin, Fatma; Cengiz, Mustafa [Sueleyman Demirel University, Department of Chemistry, Isparta, 32260 (Turkey)

    2009-04-30

    Twelve homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff base ligands containing N{sub 4} donor sets have been prepared by employing several steps. The characterization and nature of bonding of the complexes have been deduced from elemental analysis, FT-IR, molar conductivity, magnetic moment measurements and thermal analysis. The three Schiff base ligands were further identified using {sup 1}H and {sup 13}C NMR spectra. All copper(II) complexes are 1:2 electrolytes as shown by their molar conductivities ({lambda}{sub M}) in DMF and paramagnetic. The subnormal magnetic moment values of the di- and tri-nuclear complexes explained by a very strong anti-ferromagnetic interaction. The extraction ability of the ligands has been examined by the liquid-liquid extraction of selected transition metal (Mn{sup 2+}, Co{sup 2+}, Ni{sup 2+}, Cu{sup 2+}, Zn{sup 2+}, Pb{sup 2+}, Cd{sup 2+}, Hg{sup 2+}) cations. The ligands show strong binding ability toward copper(II) ion. Furthermore the homo- and hetero-nuclear copper(II) complexes were each tested for their ability to catalyse the disproportionation of hydrogen peroxide in the presence of the added base imidazole.

  14. The hype with ionic liquids as solvents

    Science.gov (United States)

    Kunz, Werner; Häckl, Katharina

    2016-09-01

    In this mini review, we give our personal opinion about the present state of the art concerning Ionic Liquids, proposed as alternative solvents. In particular, we consider their different drawbacks and disadvantages and discuss the critical aspects of the research of Ionic Liquids as solvents. Finally, we point out some aspects on potentially promising Ionic Liquid solvents.

  15. The solvent component of macromolecular crystals

    Energy Technology Data Exchange (ETDEWEB)

    Weichenberger, Christian X. [European Academy of Bozen/Bolzano (EURAC), Viale Druso 1, Bozen/Bolzano, I-39100 Südtirol/Alto Adige (Italy); Afonine, Pavel V. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Mail Stop 64R0121, Berkeley, CA 94720 (United States); Kantardjieff, Katherine [California State University, San Marcos, CA 92078 (United States); Rupp, Bernhard, E-mail: br@hofkristallamt.org [k.-k. Hofkristallamt, 991 Audrey Place, Vista, CA 92084 (United States); Medical University of Innsbruck, Schöpfstrasse 41, A-6020 Innsbruck (Austria)

    2015-04-30

    On average, the mother liquor or solvent and its constituents occupy about 50% of a macromolecular crystal. Ordered as well as disordered solvent components need to be accurately accounted for in modelling and refinement, often with considerable complexity. The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.

  16. Weekly nanoparticle albumin bound-paclitaxel in combination with cisplatin versus weekly solvent-based paclitaxel plus cisplatin as first-line therapy in Chinese patients with advanced esophageal squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Wang HY

    2016-09-01

    Full Text Available Hai-ying Wang, Zhi-hua Yao, Hong Tang, Yan Zhao, Xiao-san Zhang, Shu-na Yao, Shu-jun Yang, Yan-yan Liu Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, Henan, People’s Republic of China Objective: More effective regimens for advanced esophageal squamous cell carcinoma (ESCC are urgently needed. Therefore, a retrospective study concerning the efficacy and safety of nanoparticle albumin-bound paclitaxel plus cisplatin (nab-TP versus solvent-based paclitaxel plus cisplatin (sb-TP as a first-line therapy was conducted in Chinese patients with advanced ESCC.Methods: From June 2009 to June 2015, 32 patients were treated with nab-paclitaxel (125 mg/m2 on the first and eighth days (30 minutes infusion and cisplatin (75 mg/m2 on the second day every 21 days (nab-TP arm. Also, 43 patients were treated with solvent-based paclitaxel (80 mg/m2 intravenously on the first and eighth days and the same dose of cisplatin (sb-TP arm. The two groups were compared in terms of objective response rate (ORR, disease control rate, progression-free survival (PFS, overall survival (OS, and safety profile. OS and PFS were estimated using Kaplan–Meier methods to determine associations between chemotherapy regimens and survival outcomes.Results: Nab-TP demonstrated a higher ORR (50% vs 30%; P=0.082 and disease control rate (81% vs 65%; P=0.124 than sb-TP. Median OS was similar for nab-TP and sb-TP (12.5 vs 10.7 months; P=0.269. However, nab-TP resulted in a longer median PFS (6.1 months [95% confidence interval: 5.3–6.9] than sb-TP (5.0 months [95% confidence interval: 4.4–5.6] (P=0.029. The most common adverse events included anemia, leukopenia, neutropenia, febrile neutropenia, and thrombocytopenia in both the groups and no statistically significant differences were observed between the groups. With statistically significant differences, significantly less grade ≥3 peripheral neuropathy

  17. Weekly nanoparticle albumin-bound paclitaxel in combination with cisplatin versus weekly solvent-based paclitaxel plus cisplatin as first-line therapy in Chinese patients with advanced esophageal squamous cell carcinoma

    Science.gov (United States)

    Wang, Hai-ying; Yao, Zhi-hua; Tang, Hong; Zhao, Yan; Zhang, Xiao-san; Yao, Shu-na; Yang, Shu-jun; Liu, Yan-yan

    2016-01-01

    Objective More effective regimens for advanced esophageal squamous cell carcinoma (ESCC) are urgently needed. Therefore, a retrospective study concerning the efficacy and safety of nanoparticle albumin-bound paclitaxel plus cisplatin (nab-TP) versus solvent-based paclitaxel plus cisplatin (sb-TP) as a first-line therapy was conducted in Chinese patients with advanced ESCC. Methods From June 2009 to June 2015, 32 patients were treated with nab-paclitaxel (125 mg/m2) on the first and eighth days (30 minutes infusion) and cisplatin (75 mg/m2) on the second day every 21 days (nab-TP arm). Also, 43 patients were treated with solvent-based paclitaxel (80 mg/m2) intravenously on the first and eighth days and the same dose of cisplatin (sb-TP arm). The two groups were compared in terms of objective response rate (ORR), disease control rate, progression-free survival (PFS), overall survival (OS), and safety profile. OS and PFS were estimated using Kaplan–Meier methods to determine associations between chemotherapy regimens and survival outcomes. Results Nab-TP demonstrated a higher ORR (50% vs 30%; P=0.082) and disease control rate (81% vs 65%; P=0.124) than sb-TP. Median OS was similar for nab-TP and sb-TP (12.5 vs 10.7 months; P=0.269). However, nab-TP resulted in a longer median PFS (6.1 months [95% confidence interval: 5.3–6.9]) than sb-TP (5.0 months [95% confidence interval: 4.4–5.6]) (P=0.029). The most common adverse events included anemia, leukopenia, neutropenia, febrile neutropenia, and thrombocytopenia in both the groups and no statistically significant differences were observed between the groups. With statistically significant differences, significantly less grade ≥3 peripheral neuropathy, arthralgia, and myalgia occurred in the nab-TP arm (all Pline therapy were similar between the two regimens. There were no treatment-related deaths in either group. Conclusion Nab-paclitaxel plus cisplatin is found to be an effective and tolerable option for advanced

  18. Calculating the binding free energies of charged species based on explicit-solvent simulations employing lattice-sum methods: An accurate correction scheme for electrostatic finite-size effects

    Energy Technology Data Exchange (ETDEWEB)

    Rocklin, Gabriel J. [Department of Pharmaceutical Chemistry, University of California San Francisco, 1700 4th St., San Francisco, California 94143-2550, USA and Biophysics Graduate Program, University of California San Francisco, 1700 4th St., San Francisco, California 94143-2550 (United States); Mobley, David L. [Departments of Pharmaceutical Sciences and Chemistry, University of California Irvine, 147 Bison Modular, Building 515, Irvine, California 92697-0001, USA and Department of Chemistry, University of New Orleans, 2000 Lakeshore Drive, New Orleans, Louisiana 70148 (United States); Dill, Ken A. [Laufer Center for Physical and Quantitative Biology, 5252 Stony Brook University, Stony Brook, New York 11794-0001 (United States); Hünenberger, Philippe H., E-mail: phil@igc.phys.chem.ethz.ch [Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093 Zürich (Switzerland)

    2013-11-14

    The calculation of a protein-ligand binding free energy based on molecular dynamics (MD) simulations generally relies on a thermodynamic cycle in which the ligand is alchemically inserted into the system, both in the solvated protein and free in solution. The corresponding ligand-insertion free energies are typically calculated in nanoscale computational boxes simulated under periodic boundary conditions and considering electrostatic interactions defined by a periodic lattice-sum. This is distinct from the ideal bulk situation of a system of macroscopic size simulated under non-periodic boundary conditions with Coulombic electrostatic interactions. This discrepancy results in finite-size effects, which affect primarily the charging component of the insertion free energy, are dependent on the box size, and can be large when the ligand bears a net charge, especially if the protein is charged as well. This article investigates finite-size effects on calculated charging free energies using as a test case the binding of the ligand 2-amino-5-methylthiazole (net charge +1 e) to a mutant form of yeast cytochrome c peroxidase in water. Considering different charge isoforms of the protein (net charges −5, 0, +3, or +9 e), either in the absence or the presence of neutralizing counter-ions, and sizes of the cubic computational box (edges ranging from 7.42 to 11.02 nm), the potentially large magnitude of finite-size effects on the raw charging free energies (up to 17.1 kJ mol{sup −1}) is demonstrated. Two correction schemes are then proposed to eliminate these effects, a numerical and an analytical one. Both schemes are based on a continuum-electrostatics analysis and require performing Poisson-Boltzmann (PB) calculations on the protein-ligand system. While the numerical scheme requires PB calculations under both non-periodic and periodic boundary conditions, the latter at the box size considered in the MD simulations, the analytical scheme only requires three non

  19. Solvent-dependent assembly of discrete and continuous CoCl₂ adamantane-based ligand complexes: observations by CSI-mass spectrometry and X-ray crystallography.

    Science.gov (United States)

    Ohara, Kazuaki; Tominaga, Masahide; Azumaya, Isao; Yamaguchi, Kentaro

    2013-01-01

    Discrete and continuous coordination structures were obtained in single crystals of CoCl₂ and an adamantane-based bidentate ligand bearing imidazolyl groups, depending on the methanol concentration in a methanol-chloroform mixture. Single-crystal X-ray structure analysis revealed that the metal centers exhibited a tetrahedral geometry in the discrete complex and an octahedral geometry in the continuous metal complex. Conventional analytical methods, including UV-vis and NMR spectroscopy, could not identify those two complexes in solution. In contrast, cold-spray ionization mass spectrometry could detect differences between the discrete complex and the continuous metal complex, and ion peaks due to continuous ligand adducts were found only in the spectrum of the continuous metal complex.

  20. Solvent Extraction of Calcium into Nitrobenzene by Using an Anionic Ligand Based on Cobalt Bis(Dicarbollide) Anion with Covalently Bonded CMPO Function.

    Science.gov (United States)

    Makrlík, Emanuel; Selucký, Pavel; Vaňura, Petr

    2012-06-01

    From extraction experiments and γ-activity measurements, the exchange extraction constantcorresponding to the general equilibrium Ca2+(aq) + 2HL(nb) CaL2(nb) + 2H+(aq) taking place in the two-phase water-nitrobenzene (L- = anionic ligand based on cobalt bis(dicarbollide) anion with covalently bonded CMPO function; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (Ca2+, 2HL) = 0.0 ± 0.1. Further, the stability constant of the electroneutral complex species CaL2 in water-saturated nitrobenzene was calculated for a temperature of 25 °C : log βnb (CaL2) = 11.0 ± 0.2.

  1. Kinetics study of oil extraction from Citrus auranticum L. by solvent-free microwave extraction

    OpenAIRE

    Heri Septya Kusuma; Prilia Dwi Amelia; Cininta Admiralia; Mahfud Mahfud

    2016-01-01

    Citrus and its oil are of high economic and medicinal value because of their multiple uses, such as in the food industry, cosmetics and folk medicine. The aim of this study is to investigate the potential of solvent-free microwave extraction for the extraction of essential oils from Citrus auranticum L. peels. Specifically, this study verifies the kinetics based on second-order model and mechanism of solvent-free microwave extraction of Citrus auranticum L. peels. Solvent-free microwave extra...

  2. Alternatives to Organic Solvents in Industrial Cleaning Processes

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    1998-01-01

    cleaning agents in offset printing companies instead of volatile, toxic organic solvents. The present study is based on a project with the aim of defining other industrial processes, where organic solvents used for cleaning or degreasing can be replaced by non-volatile, low-toxic products, which are based...... on esters from fatty acids of vegetable origin (vegetable esters - VE).The study indicates that industrial cleaning/degreasing with organic solvents may be substituted with VEs on metal surfaces and on some coated surfaces, in manufacture of paints and inks, use of paints, use of inks (printing), metal...... industry, and vehicle repair and maintenance. There are, however, other elements that influence the possibility to substitute. The requirements to the resulting surface, depending on the following treatment of the surface. The character of the soilings to be removed. The possible presence of other...

  3. Solvent desorption dynamic headspace sampling of fermented dairy product volatiles.

    Science.gov (United States)

    Rankin, S A

    2001-01-01

    A method was developed based on solvent desorption dynamic headspace analysis for the identification and relative quantification of volatiles significant to the study of fermented dairy product aroma. Descriptions of applications of this method are presented including the measurement of diacetyl and acetoin in fermented milk, the evaluation of volatile-hydrocolloid interactions in dairy-based matrices, and the identification of volatiles in cheeses for canonical discriminative analysis. Advantages of this method include rapid analysis, minimal equipment investment, and the ability to analyze samples with traditional GC split/splitless inlet systems. Limitations of this method are that the sample must be in the liquid state and the inherent analytical limitation to those compounds that do not coelute with the solvent or solvent impurity peaks.

  4. Difference between Chitosan Hydrogels via Alkaline and Acidic Solvent Systems

    Science.gov (United States)

    Nie, Jingyi; Wang, Zhengke; Hu, Qiaoling

    2016-10-01

    Chitosan (CS) has generated considerable interest for its desirable properties and wide applications. Hydrogel has been proven to be a major and vital form in the applications of CS materials. Among various types of CS hydrogels, physical cross-linked CS hydrogels are popular, because they avoided the potential toxicity and sacrifice of intrinsic properties caused by cross-linking or reinforcements. Alkaline solvent system and acidic solvent system are two important solvent systems for the preparation of physical cross-linked CS hydrogels, and also lay the foundations of CS hydrogel-based materials in many aspects. As members of physical cross-linked CS hydrogels, gel material via alkaline solvent system showed significant differences from that via acidic solvent system, but the reasons behind are still unexplored. In the present work, we studied the difference between CS hydrogel via alkaline system and acidic system, in terms of gelation process, hydrogel structure and mechanical property. In-situ/pseudo in-situ studies were carried out, including fluorescent imaging of gelation process, which provided dynamic visualization. Finally, the reasons behind the differences were explained, accompanied by the discussion about design strategy based on gelation behavior of the two systems.

  5. Elucidation of adsorption mechanisms of solvent molecules with distinct functional groups on amylose tris(3,5-dimethylphenylcarbamate)-based sorbent.

    Science.gov (United States)

    Wu, Shyuan-Guey; Lin, Ang-Yen; Hsieh, Han-Yu; Tsui, Hung-Wei

    2016-08-19

    Although polysaccharide derivative-based sorbents have been widely used for chiral separation, for a long time it remained unclear how these CSPs interact with the molecules associated with different functional groups. In this study, six molecules were chosen for retention behavior studies: acetone (AC), tetrahydrofuran (THF), methanol (MET), isopropanol (IPA), tert-butanol (TBA), and benzene (BZN). An immobilized amylose carbamate stationary phase, amylose tris(3,5-dimethylphenylcarbamate)-based sorbent, or Chiralpak IA, was used. Van't Hoff plots of ln k versus 1/T showed that alcohol molecules may simultaneously form two H-bonds with the IA sorbent. The results of density functional theory simulations and IR spectra support this inference showing that alcohol may bind with amide groups in three possible configurations. Frontal tests of AC and IPA were performed to estimate adsorbed solute concentration. Langmuir isotherm for IPA adsorption and mass action model for IPA self-aggregation were used for analyzing the IPA frontal results. Average IPA aggregation numbers range from 1.4 to 2.3. More than fifty percent of IPA molecules were found to be in aggregate form. From the frontal test results, thermodynamic properties of the adsorptions were determined. Retention behaviors of the five solutes as a function of IPA concentration were investigated. The absolute values B of the slopes from plots of the logarithms of the retention factor versus the logarithms of the IPA concentration increase in the order THF

  6. Effect of solvents on the characteristics of rosin walled microcapsules prepared by a solvent evaporation technique.

    Science.gov (United States)

    Sheorey, D S; Dorle, A K

    1991-01-01

    Rosin microcapsules were prepared by a solvent evaporation technique using solvents with different rates of evaporation. Sulphadiazine was used as a model drug. The microcapsules were studied for their size, drug content, wall thickness, surface characteristics and in vitro release. The mean diameter increased and the drug content decreased as the rate of evaporation of the solvent increased. Fast evaporating solvents produced thick walled microcapsules with innumerable surface pores/cracks compared with slow evaporating solvents.

  7. Water as a solvent for life

    Science.gov (United States)

    Pohorille, Andrew

    2015-08-01

    “Follow the water” is our basic strategy in searching for life in the universe. The universality of water as the solvent for living systems is usually justified by arguing that water supports the rich organic chemistry that seeds life, but alternative chemistries are possible in other organic solvents. Here, other, essential criteria for life that have not been sufficiently considered so far, will be discussed.Life is based on non-covalent interactions. They might be either specific (enzyme-substrate interactions, selective ion transport) or nonspecific (lipid-lipid or lipid-protein interactions). Their strength needs to be properly tuned, and this is mediated by the solvent. If interactions are too weak, there might be undesired response to natural fluctuations of physical and chemical parameters. If they are too strong it could impede kinetics and energetics of cellular processes. Thus, the solvent must allow for balancing these interactions, which provides strong constraints for life.Water exhibits a remarkable trait that it promotes both solvophobic and solvophilic interactions. Solvophobic (hydrophobic in the case of water) interactions are necessary for self-organization of matter. They are responsible, among others, for the formation of membranes and protein folding. The diversity of structures supported by hydrophobic interactions is the hallmark of terrestrial life responsible for its diversity, evolution and the ability to survive environmental changes. Solvophilic interactions, in turn, are needed to ensure solubility of polar species. Water offers a large temperature domain of stable liquid and the characteristic hydrophobic effects are a consequence of the temperature insensitivity of essential properties of its liquid state. Water, however, might not be the only liquid with these properties. Properties of water and other pure liquids or their mixtures that have a high dielectric constant and simultaneously support self-organization will be

  8. Synthesis, crystal structure and effect of deuterated solvents and temperature on visible and near infrared luminescence of N4-donor Schiff base lanthanide complexes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shuo; Fan, Rui-Qing; Gao, Song; Wang, Xinming; Yang, Yu-Lin, E-mail: ylyang@hit.edu.cn

    2014-05-01

    A series of lanthanide complexes [LnL(NO{sub 3}){sub 3}]·CH{sub 3}CN [Ln=Ce, (1• Ce); Nd, (2• Nd); Tb, (3• Tb); Dy, (4• Dy); Ho, (5• Ho); Er, (6• Er); Tm, (7• Tm); Yb (8• Yb)] have been synthesized by the reaction of N4 chelate ligand N,N'-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine (L) with lanthanide salts. Photoluminescence spectra of complexes 2• Nd, 3• Tb, 4• Dy, and 8• Yb show the strong characteristic luminescence from visible to near infrared (NIR) region. Further, the singlet state (32,467 cm{sup −1}) and the lowest triplet (23,202 cm{sup −1}) energy level of L are calculated, indicating that the energy transfer from L to Tb{sup 3+} ion is more effective than that to Dy{sup 3+} ion. An extended work is developed to discuss on the effect of deuterated reagent and temperature on luminescent properties of 3• Tb and 8• Yb. - Highlights: • A series of N4-donor Schiff base lanthanide complex are designed and synthesized. • The characteristic luminescence from visible to near infrared region could be revealed. • The influence of deuterated reagent and temperature on luminescent properties is described.

  9. Modelling the surface free energy parameters of polyurethane coats-part 1. Solvent-based coats obtained from linear polyurethane elastomers.

    Science.gov (United States)

    Król, Piotr; Lechowicz, Jaromir B; Król, Bożena

    2013-04-01

    Polyurethane elastomers coating were synthesised by using typical diisocyanates, polyether and polyester polyols and HO-tertiary amines or diols as a chain extenders. Mole fractions of structural fragments (κexp) responsible for the polar interactions within polyurethane chains were calculated by (1)H NMR method. Obtained results were confronted with the analogous parameter values (κtheor) calculated on the basis of process stoichiometry, considering the stage of the production of isocyanate prepolymers and reaction of their extension for polyurethanes. Trials of linear correlation between the κexp parameters and surface free energy (SFE) values of investigated coatings were presented. SFE values were determined by Owens-Wendt method, using contact angles measured with the goniometric method. Based on achieved results, another empirical models, allowing for prediction the influence of the kind of polyurethane raw materials on SFE values of received coatings were determined. It was found that it is possible to regulate the SFE in the range millijoules per cubic metre by the selection of appropriate substrates. It has been found that use of 2,2,3,3-tetrafluoro-1,4-butanediol as a fluorinated extender of prepolymer chains is essential to obtain coatings with increased hydrophobicity, applied among others as biomaterials-next to diphenylmethane diisocyanate and polyoxyethylene glycol.

  10. Coal extraction by aprotic dipolar solvents. Final report. [Tetramethylurea, hexa-methylphosphoramide

    Energy Technology Data Exchange (ETDEWEB)

    Sears, J T

    1985-12-01

    The overall goals of this project were to examine the rate and amount of extraction of coals at low temperature by a class of solvents with a generic structure to include tetramethylurea (TMU) and hexa-methylphosphoramide (HMPA) and to examine the nature of the extracted coal chemicals. The class of solvents with similar action, however, can be classified as aprotic, base solvents or, somewhat more broadly, specific solvents. The action of solvents by this last classification was then examined to postulate a mechanism of attack. Experimental work was conducted to explain the specific solvent attack including (1) pure solvent extraction, (2) extraction in mixtures with otherwise inert solvents and inhibitors, and (3) extraction with simultaneous catalytic enhancement attempts including water-gas shift conversion. Thus nuclear magnetic resonance (NMR) and gas-chromatograph mass spectrometer (GC-MS) analysis of extract molecules and extraction with high-pressure CO in TMU (plus 2% H2O) was performed. Effects of solvent additives such as cumene and quinone of large amounts of inert solvents such as tetralin, liminone, or carbon disulfide on extraction were also determined. Results are discussed. 82 refs., 36 figs., 37 tabs.

  11. Comparison of dispersive liquid-liquid microextraction based on organic solvent and ionic liquid combined with high-performance liquid chromatography for the analysis of emodin and its metabolites in urine samples.

    Science.gov (United States)

    Tian, Jie; Chen, Xuan; Bai, Xiaohong

    2012-01-01

    In this paper, two methods based on organic solvent dispersive liquid-liquid microextraction (OS-DLLME) and ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) coupled with high-performance liquid chromatography have been critically compared for analyzing emodin and its metabolites (aloe-emodin, anthraquinone-2-carboxylic acid, rhein, danthron, chrysophanol and physcion) in urine samples. Several important parameters influencing the extraction recoveries of DLLME were carefully optimized. Under optimal conditions, the enrichment factors (EFs) for emodin and its metabolites by OS-DLLME and IL-DLLME were within the range of 90-295 and 63-192 respectively; the relative standard deviations (RSDs, n=3) for intra-day and inter-day precision were lower than 7.2 and 8.7% by OS-DLLME, and lower than 5.7 and 6.4% by IL-DLLME; the recoveries of emodin and its metabolites were from 87.1 to 105% for OS-DLLME and from 94.8 to 103% for IL-DLLME, respectively. There were no significant deviations between the two methods for the determination of emodin and its metabolites. From the results of HPLC/UV of urine sample after DLLME, the metabolites aloe-emodin, rhein, chrysophanol and physcion were identified by comparing the retention times with the standards. From the results of HPLC/MS, anthraquinone-2-carboxylic acid and danthron as unreported metabolites of emodin were found.

  12. Optimisation of the extraction of olive (Olea europaea) leaf phenolics using water/ethanol-based solvent systems and response surface methodology.

    Science.gov (United States)

    Mylonaki, Stefania; Kiassos, Elias; Makris, Dimitris P; Kefalas, Panagiotis

    2008-11-01

    An experimental setup based on a 2(3) full-factorial, central-composite design was implemented with the aim of optimising the recovery of polyphenols from olive leaves by employing reusable and nontoxic solutions composed of water/ethanol/citric acid as extracting media. The factors considered were (i) the pH of the medium, (ii) the extraction time and (iii) the ethanol concentration. The model obtained produced a satisfactory fit to the data with regard to total polyphenol extraction (R(2) = 0.91, p = 0.0139), but not for the antiradical activity of the extracts (R(2) = 0.67, p = 0.3734). The second-order polynomial equation obtained after analysing the experimental data indicated that ethanol concentration and time mostly affected the extraction yield, but that increased pH values were unfavourable in this regard. The maximum theoretical yield was calculated to be 250.2 +/- 76.8 mg gallic acid equivalent per g of dry, chlorophyll-free tissue under optimal conditions (60% EtOH, pH 2 and 5 h). Liquid chromatography-electrospray ionisation mass spectrometry of the optimally obtained extract revealed that the principal phytochemicals recovered were luteolin 7-O-glucoside, apigenin 7-O-rutinoside and oleuropein, accompanied by smaller amounts of luteolin 3',7-O-diglucoside, quercetin 3-O-rutinoside (rutin), luteolin 7-O-rutinoside and luteolin 3'-O-glucoside. Simple linear regression analysis between the total polyphenol and antiradical activity values gave a low and statistically insignificant correlation (R(2) = 0.273, p > 0.05), suggesting that it is not the sheer amount of polyphenols that provides high antioxidant potency; instead, this potency is probably achieved through interactions among the various phenolic constituents.

  13. Renewable feedstocks in green solvents: thermodynamic study on phase diagrams of D-sorbitol and xylitol with dicyanamide based ionic liquids.

    Science.gov (United States)

    Paduszyński, Kamil; Okuniewski, Marcin; Domańska, Urszula

    2013-06-13

    Experimental and theoretical studies on thermodynamic properties of three ionic liquids based on dicyanamide anion (namely, 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-1-methylpyrrolidinium dicyanamide, and 1-butyl-1-methylpiperidinium dicyanamide) and their binary mixtures with sugar alcohols (D-sorbitol and xylitol) were conducted in order to assess the applicability of the salts ionic liquids for dissolution of those biomass-related materials. Density and dynamic viscosity (at ambient pressure) of pure ionic liquids are reported in the temperature range from T = 293.15 to 363.15 K. Solid-liquid equilibrium phase diagrams in binary systems {sugar alcohol + ionic liquid} were measured with dynamic method up to the fusion temperature of sugar alcohol. The impact of the chemical structure of both the ionic liquid and sugar alcohol were established and discussed. For the very first time, the experimental solubility data were reproduced and analyzed in terms of equation of state rooted in statistical mechanics. For this purpose, perturbed-chain statistical associating fluid theory (PC-SAFT) was employed. In particular, new molecular schemes for the ionic liquids, D-sorbitol, and xylitol were proposed, and then the pure chemicals were parametrized by using available density and vapor pressure data. The model allowed accurate correlation of pure fluid properties for both ionic liquids and sugar alcohols, when the association term is taken into account. The results of solid-liquid equilibria modeling were also satisfactory. However, one or two adjustable binary corrections to the adopted combining rules were required to be adjusted in order to accurately capture the phase behavior. It was shown that a consistent thermodynamic description of extremely complex systems can be achieved by using relatively simple (but physically grounded) theoretical tools and molecular schemes.

  14. How membrane permeation is affected by donor delivery solvent.

    Science.gov (United States)

    Binks, Bernard P; Fletcher, Paul D I; Johnson, Andrew J; Elliott, Russell P

    2012-11-28

    We investigate theoretically and experimentally how the rate and extent of membrane permeation is affected by switching the donor delivery solvent from water to squalane for different permeants and membranes. In a model based on rate-limiting membrane diffusion, we derive explicit equations showing how the permeation extent and rate depend mainly on the membrane-donor and membrane-receiver partition coefficients of the permeant. Permeation results for systems containing all combinations of hydrophilic or hydrophobic donor solvents (aqueous solution or squalane), permeants (caffeine or testosterone) and polymer membranes (cellulose or polydimethylsiloxane) have been measured using a cell with stirred donor and re-circulating receiver compartments and continuous monitoring of the permeant concentration in the receiver phase. Relevant partition coefficients are also determined. Quantitative comparison of model and experimental results for the widely-differing permeation systems successfully enables the systematic elucidation of all possible donor solvent effects in membrane permeation. For the experimental conditions used here, most of the permeation systems are in agreement with the model, demonstrating that the model assumptions are valid. In these cases, the dominant donor solvent effects arise from changes in the relative affinities of the permeant for the donor and receiver solvents and the membrane and are quantitatively predicted using the separately measured partition coefficients. We also show how additional donor solvent effects can arise when switching the donor solvent causes one or more of the model assumptions to be invalid. These effects include a change in rate-limiting step, permeant solution non-ideality and others.

  15. Solvent viscosity dependence for enzymatic reactions

    CERN Document Server

    Sitnitsky, A E

    2008-01-01

    A mechanism for relationship of solvent viscosity with reaction rate constant at enzyme action is suggested. It is based on fluctuations of electric field in enzyme active site produced by thermally equilibrium rocking (cranckshaft motion) of the rigid plane (in which the dipole moment $\\approx 3.6 D$ lies) of a favourably located and oriented peptide group (or may be a few of them). Thus the rocking of the plane leads to fluctuations of the electric field of the dipole moment. These fluctuations can interact with the reaction coordinate because the latter in its turn has transition dipole moment due to separation of charges at movement of the reacting system along it. The rocking of the plane of the peptide group is sensitive to the microviscosity of its environment in protein interior and the latter is a function of the solvent viscosity. Thus we obtain an additional factor of interrelationship for these characteristics with the reaction rate constant. We argue that due to the properties of the cranckshaft ...

  16. [Generic method for determination of volatile organic solvents in cosmetics].

    Science.gov (United States)

    Da, Jing; Huang, Xianglu; Wang, Gangli; Cao, Jin; Zhang, Qingsheng

    2014-11-01

    A generic screening, confirmation and determination method was established based on 36 commonly used volatile organic solvents in cosmetics by headspace gas chromatography- mass spectrometry (GC-MS). This method included a database for pilot screening and identifi- cation of those solvents and their quantitative method. Pilot screening database was composed by two sections, one was household section built by two columns with opposite polarities (col- umn VF-1301 ms and DB-5 ms) using retention index in different column systems as qualitative parameter, and the other was NIST MS search version 2.0. Meanwhile, the determination method of the 36 volatile solvents was developed with GC-MS. Cosmetic samples were dissolved in water and transferred to a headspace vial. After 30 min equilibration at 60 °C, the samples were analyzed by GC-MS equipped with a capillary chromatographic column VF-1301 ms. The external calibration was used for quantification. The limits of detection were from 0.01 to 3.3 μg/g, and the recoveries were from 60.77% to 126.6%. This study provided a generic method for pilot screening, identification, and quantitation of volatile organic solvents in cosmetics, and may solve the problem that different analytical methods need to be developed for different targeted compounds and pilot screening for potential candidate solvent residues.

  17. Dynamics around solutes and solute-solvent complexes in mixed solvents.

    Science.gov (United States)

    Kwak, Kyungwon; Park, Sungnam; Fayer, M D

    2007-09-04

    Ultrafast 2D-IR vibrational echo experiments, IR pump-probe experiments, and FT-IR spectroscopy of the hydroxyl stretch of phenol-OD in three solvents, CCl4, mesitylene (1, 3, 5 trimethylbenzene), and the mixed solvent of mesitylene and CCl4 (0.83 mole fraction CCl4), are used to study solute-solvent dynamics via observation of spectral diffusion. Phenol forms a complex with Mesitylene. In the mesitylene solution, there is only complexed phenol; in the CCl4 solution, there is only uncomplexed phenol; and in the mixed solvent, both phenol species are present. Dynamics of the free phenol in CCl4 or the mixed solvent are very similar, and dynamics of the complex in mesitylene and in the mixed solvent are very similar. However, there are differences in the slowest time scale dynamics between the pure solvents and the mixed solvents. The mixed solvent produces slower dynamics that are attributed to first solvent shell solvent composition variations. The composition variations require a longer time to randomize than is required in the pure solvents, where only density variations occur. The experimental results and recent MD simulations indicate that the solvent structure around the solute may be different from the mixed solvent's mole fraction.

  18. Analytical methods for residual solvents determination in pharmaceutical products.

    Science.gov (United States)

    Grodowska, Katarzyna; Parczewski, Andrzej

    2010-01-01

    Residual solvents (RS) are not desirable substances in the final pharmaceutical product and their acceptable limits have been published in pharmacopoeias and ICH guidelines. The intension of this paper was to review and discuss some of the current analytical procedures including gas chromatographic (GC) and other alternative techniques which are used for residual solvents determination. GC methods have been developed to monitor this kind of impurities routinely. The most popular techniques of sample introduction into the gas chromatograph include direct injection, static or dynamic headspace, solid-phase microextraction and single drop microextraction. Different separation techniques like two dimensional chromatography or multicapillary chromatography were compared with classical separation mode with use of single capillary column. Also alternative methodologies for residual solvents testing were discussed in this review. In conclusions, gas chromatography-based procedures were described as the most appropriate because of the lowest detection limits, ease of sample preparation and specificity.

  19. Effective lipid extraction from algae cultures using switchable solvents

    NARCIS (Netherlands)

    Samori, Chiara; Lopez Barreiro, Diego; Vet, Robin; Pezzolesi, Laura; Brilman, Derk W.F. (Wim); Galletti, Paola; Tagliavini, Emilio

    2013-01-01

    A new procedure based on switchable polarity solvents (SPS) was proposed for lipid extraction of wet algal samples or cultures, thereby circumventing the need for an energy intensive drying step and facilitating easy recovery of the lipids from the extraction liquid. Lipids were extracted by using N

  20. Synthesis of Porous Inorganic Hollow Fibers without Harmful Solvents

    NARCIS (Netherlands)

    Shukla, S.; Wit, de Patrick; Luiten-Olieman, Mieke W.J.; Kappert, Emiel J.; Nijmeijer, Arian; Benes, Nieck E.

    2015-01-01

    A route for the fabrication of porous inorganic hollow fibers with high surface-area-to-volume ratio that avoids harmful solvents is presented. The approach is based on bio-ionic gelation of an aqueous mixture of inorganic particles and sodium alginate during wet spinning. In a subsequent thermal tr

  1. Biological Treatment of Solvent-Based Paint

    Science.gov (United States)

    2011-01-01

    GAC granular activated carbon H2O water HP horsepower IWG inches of water gauge IWTC Industrial Wastewater Treatment Complex JGDM Joint...biofiltration system) were procured, installed, and tested over a 1-yr period in cooperation with the Industrial Wastewater Treatment Complex (IWTC) in...were steam reforming, incineration, ultrafiltration , activated carbon, and photochemical oxidation. Because the paint is not suspended in water, its

  2. Biological Treatment of Solvent-Based Paint

    Science.gov (United States)

    2011-01-01

    that form the chemical backbone of numerous natural products (e.g., triglycerides , cellulose, lignin, proteins, and chitin) for which bacteria have...evolved a diverse array of enzymes that enable them to use these compounds as sources of food and energy. Thus, it would be expected that bacteria...degradation of polyurethane resins, specifically with isocyanate groups. If complete hydrolysis does not occur, the alcohol that forms when the isocyanate

  3. Tuning the Morphology of Pharmaceutical Compounds via Model Based Solvent Selection%通过模型为基础的溶液选择来调控药品化合物的形貌

    Institute of Scientific and Technical Information of China (English)

    A.T.Karunanithi; C.Acquah; L.E.K.Achenie

    2008-01-01

    In this paper we present a strategy for tuning the crystal morphology of pharmaceutical compounds by the appropriate choice of solvent via an optimization model. A three-stage approach involving a pre-design stage, a product design stage and a post-design experimental verification stage is presented. The pre-design stage addresses the formulation of the property constraint for crystal morphology. This involves crystallization experiments and development of property models and constraints for morphology. In the design stage various property requirements for the solvent along with crystal morphology are considered and the product design problem is formulated as a mixed integer nonlinear programming model. The design stage provides an optimal solvent/list of candidate solvents. Similar to the pre-design stage, in the post design experimental verification stage, the morphology of the crystals (precipitated from the designed solvent) is verified through crystallization experiments followed by productcharacterization via scanning electron microscopy, powder X-ray diffraction imaging and Fourier transform spectra analysis.

  4. (Co-)solvent selection for single-wall carbon nanotubes: best solvents, acids, superacids and guest-host inclusion complexes.

    Science.gov (United States)

    Torrens, Francisco; Castellano, Gloria

    2011-06-01

    Analysis of 1-octanol-water, cyclohexane-water and chloroform (CHCl(3))-water partition coefficients P(o-ch-cf) allows calculation of molecular lipophilicity patterns, which show that for a given atom log P(o-ch-cf) is sensitive to the presence of functional groups. Program CDHI does not properly differentiate between non-equivalent atoms. The most abundant single-wall carbon nanotube (SWNT), (10,10), presents a relatively small aqueous solubility and large elementary polarizability, P(o-ch-cf) and kinetic stability. The SWNT solubility is studied in various solvents, finding a class of non-hydrogen-bonding Lewis bases with good solubility. Solvents group into three classes. The SWNTs in some organic solvents are cationic while in water/Triton X mixture are anionic. Categorized solubility is semiquantitatively correlated with solvent parameters. The coefficient of term β is positive while the ones of ε and V negative. The electron affinity of d-glucopyranoses (d-Glcp(n)) suggests the formation of colloids of anionic SWNTs in water. Dipole moment for d-Glcp(n)-linear increases with n until four in agreement with 18-fold helix. The I(n)(z-) and SWNT(-) are proposed to form inclusion complexes with cyclodextrin (CD) and amylose (Amy). Starch, d-Glcp, CD and Amy are proposed as SWNT co-solvents. Guests-hosts are unperturbed. A central channel expansion is suggested.

  5. An atom efficiency, solvent-free synthesis of some new heterocyclic imines and antibacterial activity

    Directory of Open Access Journals (Sweden)

    Subhash B. Junne

    2012-04-01

    Full Text Available A solvent-free condensation of substituted aryl amines with indole-3-aldehyde in presence of catalytic amount of acetic acid at room temperature in combination with grinding to yield new series of heterocyclic imines (Schiff bases. The simple reaction procedure, short reaction time, no need of organic solvent and high yields make this protocol practical and economically attractive.

  6. Solvent-dependent on/off valving using selectively permeable barriers in paper microfluidics

    NARCIS (Netherlands)

    Salentijn, G.I.J.; Hamidon, N.N.; Verpoorte, E.

    2016-01-01

    We report on a new way to control solvent flows in paper microfluidic devices, based on the local patterning of paper with alkyl ketene dimer (AKD) to form barriers with selective permeability for different solvents. Production of the devices is a two-step process. In the first step, AKD-treated pap

  7. Phase behaviour of colloids suspended in a near-critical solvent : A mean-field approach

    NARCIS (Netherlands)

    Edison, John R.; Belli, Simone; Evans, Robert; Van Roij, René; Dijkstra, Marjolein

    2015-01-01

    Colloids suspended in a binary solvent may, under suitable thermodynamic conditions, experience a wide variety of solvent-mediated interactions that can lead to colloidal phase transitions and aggregation phenomena. We present a simple mean-field theory, based on free-volume arguments, that describe

  8. Mathematical modelling of simultaneous solvent evaporation and chemical curing in thermoset coatings: A parameter study

    DEFF Research Database (Denmark)

    Kiil, Søren

    2011-01-01

    A mathematical model, describing the curing behaviour of a two-component, solvent-based, thermoset coating, is used to conduct a parameter study. The model includes curing reactions, solvent intra-film diffusion and evaporation, film gelation, vitrification, and crosslinking. A case study with a ...

  9. Solvent effects on the formation of nanoparticles and multilayered coatings based on hydrogen-bonded interpolymer complexes of poly(acrylic acid) with homo- and copolymers of N-vinyl pyrrolidone.

    Science.gov (United States)

    Zhunuspayev, Daulet E; Mun, Grigoriy A; Hole, Patrick; Khutoryanskiy, Vitaliy V

    2008-12-02

    The formation of hydrogen-bonded interpolymer complexes between poly(acrylic acid) and poly(N-vinyl pyrrolidone) as well as amphiphilic copolymers of N-vinyl pyrrolidone with vinyl propyl ether has been studied in aqueous and organic solutions. It was demonstrated that introduction of vinyl propyl ether units into the macromolecules of the nonionic polymer enhances their ability to form complexes in aqueous solutions due to more significant contribution of hydrophobic effects. The complexation was found to be a multistage process that involves the formation of primary polycomplex particles, which further aggregate to form spherical nanoparticles. Depending on the environmental factors (pH, solvent nature), these nanoparticles may either form stable colloidal solutions or undergo further aggregation, resulting in precipitation of interpolymer complexes. In organic solvents, the intensity of complex formation increases in the following order: methanol complexes on glass surfaces. It was demonstrated that the solvent nature affects the efficiency of coating deposition.

  10. Dissociation of a strong acid in neat solvents: diffusion is observed after reversible proton ejection inside the solvent shell.

    Science.gov (United States)

    Veiga-Gutiérrez, Manoel; Brenlla, Alfonso; Carreira Blanco, Carlos; Fernández, Berta; Kovalenko, Sergey A; Rodríguez-Prieto, Flor; Mosquera, Manuel; Lustres, J Luis Pérez

    2013-11-14

    Strong-acid dissociation was studied in alcohols. Optical excitation of the cationic photoacid N-methyl-6-hydroxyquinolinium triggers proton transfer to the solvent, which was probed by spectral reconstruction of picosecond fluorescence traces. The process fulfills the classical Eigen-Weller mechanism in two stages: (a) solvent-controlled reversible dissociation inside the solvent shell and (b) barrierless splitting of the encounter complex. This can be appreciated only when fluorescence band integrals are used to monitor the time evolution of the reactant and product concentrations. Band integrals are insensitive to solvent dynamics and report relative concentrations directly. This was demonstrated by first measuring the fluorescence decay of the conjugate base across the full emission band, independently of the proton-transfer reaction. Multiexponential decay curves at single wavelengths result from a dynamic red shift of fluorescence in the course of solvent relaxation, whereas clean single exponential decays are obtained if the band integral is monitored instead. The extent of the shift is consistent with previously reported femtosecond transient absorption measurements, continuum theory of solvatochromism, and molecular properties derived from quantum chemical calculations. In turn, band integrals show clean biexponential decay of the photoacid and triexponential evolution of the conjugate base in the course of the proton transfer to solvent reaction. The dissociation step follows the slowest stage of solvation, which was measured here independently by picosecond fluorescence spectroscopy in five aliphatic alcohols. Also, the rate constant of the encounter-complex splitting stage is compatible with proton diffusion. Thus, for this photoacid, both stages reach the highest possible rates: solvation and diffusion control. Under these conditions, the concentration of the encounter complex is substantial during the earliest nanosecond.

  11. OCCUPATIONAL SOLVENT EXPOSURE ASSOCIATED WITH DEVELOPMENTAL TOXICITY

    Directory of Open Access Journals (Sweden)

    Alina-Costina LUCA

    2016-05-01

    Full Text Available Organic solvent is a broad term that applies to many classes of chemicals. The solvent (benzene, toluene etc. aspects of occupational exposure are reviewed via the examination of the use, occurrence, and disposition as well as population’s potential of risk. The general public can be exposed to solvent in ambient air as a result of its occurrence in paint process. Solvents are primarily irritants to the skin and mucous membranes and have narcotic properties at high concentrations. Published epidemiological data identified various types of birth defects in certain occupations.

  12. A solvent tolerant isolate of Enterobacter aerogenes.

    Science.gov (United States)

    Gupta, Anshu; Singh, Rajni; Khare, S K; Gupta, M N

    2006-01-01

    A solvent tolerant strain of Enterobacter aerogenes was isolated from soil by cyclohexane enrichment. Presence of cyclohexane (20%) in culture media prolonged the lag phase and caused reduction in biomass. Transmission electron micrographs showed convoluted cell membrane and accumulation of solvent in case of the cells grown in cyclohexane. The Enterobacter isolate was able to grow in the range of organic solvents having log P above 3.2 and also in presence of mercury, thus showing potential for treatment of solvent rich wastes.

  13. Extractive Distillation with Salt in Solvent

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Extractive distillation with salt in solvent is a new process for producing anhydrous ethanol by combining the principle of "salt effect" and some traditional extractive distillation methods. Compared with the common extractive distillation the performance of solvent is improved, the recycling amount of solvent is reduced to 1/4-1/5, and the number of theoretical plates is reduced to 1/3. Energy consumption and cost of equipment are also reduced and continuous production is realized. High efficiency and low solvent wastage make this technique feasible.

  14. Organic solvent use in enterprises in Japan.

    Science.gov (United States)

    Nagasawa, Yasuhiro; Ukai, Hirohiko; Okamoto, Satoru; Samoto, Hajime; Itoh, Kenji; Moriguchi, Jiro; Sakuragi, Sonoko; Ohashi, Fumiko; Takada, Shiro; Kawakami, Tetsuya; Ikeda, Masayuki

    2011-01-01

    This study was initiated to elucidate possible changes in types of organic solvents (to be called solvents in short) used in enterprises in Japan through comparison of current solvent types with historical data since 1983. To investigate current situation in solvent use in enterprises, surveys were conducted during one year of 2009 to 2010. In total, workroom air samples in 1,497 unit workplaces with solvent use were analyzed in accordance with regulatory requirements. Typical use pattern of solvents was as mixtures, accounting for >70% of cases. Adhesives spreading (followed by adhesion) was relatively common in small-scale enterprises, whereas printing and painting work was more common in middle-scale ones, and solvent use for testing and research purpose was basically in large-scaled enterprises. Through-out printing, painting, surface coating and adhesive application, toluene was most common (being detected in 49 to 82% of workplaces depending on work types), whereas isopropyl alcohol was most common (49%) in degreasing, cleaning and wiping workplaces. Other commonly used solvents were methyl alcohol, ethyl acetate and acetone (33 to 37%). Comparison with historical data in Japan and literature-retrieved data outside of Japan all agreed with the observation that toluene is the most commonly used solvent. Application of trichloroethylene and 1,1,1-trichloroethane, once common in 1980s, has ceased to exist in recent years.

  15. Solvent-induced structural diversity in tetranuclear Ni(ii) Schiff-base complexes: the first Ni4 single-molecule magnet with a defective dicubane-like topology.

    Science.gov (United States)

    Herchel, Radovan; Nemec, Ivan; Machata, Marek; Trávníček, Zdeněk

    2016-11-22

    Two tetranuclear Ni(II) complexes, namely [Ni4(L)4(CH3OH)3(H2O)]·CH3OH (1) and (Pr3NH)2[Ni4(L)4(CH3COO)2] (2, Pr3N = tripropylamine), were synthesized from a tridentate Schiff base ligand H2L (2-[(E)-(2-hydroxybenzylidene)amino]phenol) and Ni(CH3COO)2·4H2O, using different solvents and their ratios (CH3OH and/or CH2Cl2). The prepared Ni4 complexes are of different structural types, involving an Ni4O4 cubane-like core (1) and Ni4O6 defective dicubane-like core (2), with all the Ni atoms hexacoordinated. The complexes were characterized by elemental analysis, FT-IR spectroscopy, variable temperature and field magnetic measurements, and single crystal X-ray analysis. The DFT and CASSCF/NEVPT2 theoretical calculations were utilized to reveal information about the isotropic exchange parameters (Jij) and single-ion zero-field splitting parameters (Di, Ei). The variable temperature magnetic data suggested the competition of the antiferromagnetic and ferromagnetic intracluster interactions in compound 1, which is in contrast to compound 2, where all intracluster interactions are ferromagnetic resulting in the ground spin state S = 4 with an easy-axis type of anisotropy quantified by the axial zero-field splitting parameter D = -0.81 cm(-1). This resulted in the observation of a field-induced slow-relaxation of magnetization (U = 3.3-6.7 K), which means that the complex 2 represents the first Ni4 single-molecule magnet with the defective dicubane-like topology.

  16. Understanding Solvent Manipulation of Morphology in Bulk-Heterojunction Organic Solar Cells.

    Science.gov (United States)

    Chen, Yuxia; Zhan, Chuanlang; Yao, Jiannian

    2016-10-06

    Film morphology greatly influences the performance of bulk-heterojunction (BHJ)-structure-based solar cells. It is known that an interpenetrating bicontinuous network with nanoscale-separated donor and acceptor phases for charge transfer, an ordered molecular packing for exciton diffusion and charge transport, and a vertical compositionally graded structure for charge collection are prerequisites for achieving highly efficient BHJ organic solar cells (OSCs). Therefore, control of the morphology to obtain an ideal structure is a key problem. For this solution-processing BHJ system, the solvent participates fully in film processing. Its involvement is critical in modifying the nanostructure of BHJ films. In this review, we discuss the effects of solvent-related methods on the morphology of BHJ films, including selection of the casting solvent, solvent mixture, solvent vapor annealing, and solvent soaking. On the basis of a discussion on interaction strength and time between solvent and active materials, we believe that the solvent-morphology-performance relationship will be clearer and that solvent selection as a means to manipulate the morphology of BHJ films will be more rational.

  17. Quantification of residual solvents in antibody drug conjugates using gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Medley, Colin D., E-mail: medley.colin@gene.com [Genentech Inc., Small Molecule Pharmaceutical Sciences, 1 DNA Way, South San Francisco, CA 94080 (United States); Kay, Jacob [Research Pharmaceutical Services, 520 Virginia Dr. Fort, Washington, PA (United States); Li, Yi; Gruenhagen, Jason; Yehl, Peter; Chetwyn, Nik P. [Genentech Inc., Small Molecule Pharmaceutical Sciences, 1 DNA Way, South San Francisco, CA 94080 (United States)

    2014-11-19

    Highlights: • Sensitive residual solvents detection in ADCs. • 125 ppm QL for common conjugation solvents. • Generic and validatable method. - Abstract: The detection and quantification of residual solvents present in clinical and commercial pharmaceutical products is necessary from both patient safety and regulatory perspectives. Head-space gas chromatography is routinely used for quantitation of residual solvents for small molecule APIs produced through synthetic processes; however residual solvent analysis is generally not needed for protein based pharmaceuticals produced through cultured cell lines where solvents are not introduced. In contrast, antibody drug conjugates and other protein conjugates where a drug or other molecule is covalently bound to a protein typically use solvents such as N,N-dimethylacetamide (DMA), N,N‑dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or propylene glycol (PG) to dissolve the hydrophobic small molecule drug for conjugation to the protein. The levels of the solvent remaining following the conjugation step are therefore important to patient safety as these parental drug products are introduced directly into the patients bloodstream. We have developed a rapid sample preparation followed by a gas chromatography separation for the detection and quantification of several solvents typically used in these conjugation reactions. This generic method has been validated and can be easily implemented for use in quality control testing for clinical or commercial bioconjugated products.

  18. Additive diffusion from LDPE slabs into contacting solvents as a function of solvent absorption

    NARCIS (Netherlands)

    Helmroth, I.E.; Dekker, M.; Hankemeier, Th.

    2003-01-01

    This article describes the simultaneous diffusion of a migrant and a solvent in low density polyethylene (LDPE). The migrant (Irganox 1076) moves out of the slab, while the solvent (isooctane, n-heptane or cyclohexane) moves inwards. Solvent absorption was measured separately by following the increa

  19. Additive Diffusion from LDPE Slabs into Contacting Solvents as a Function of Solvent Absorption

    NARCIS (Netherlands)

    Helmroth, I.E.; Dekker, M.; Hankemeier, T.

    2003-01-01

    This article describes the simultaneous diffusion of a migrant and a solvent in low density polyethylene (LDPE). The migrant (Irganox 1076) moves out of the slab, while the solvent (isooctane, n-heptane or cyclohexane) moves inwards. Solvent absorption was measured separately by following the increa

  20. Modeling Solvent Broadening on the Vibronic Spectra of a Series of Coumarin Dyes. From Implicit to Explicit Solvent Models.

    Science.gov (United States)

    Cerezo, Javier; Avila Ferrer, Francisco J; Prampolini, Giacomo; Santoro, Fabrizio

    2015-12-08

    We present a protocol to estimate the solvent-induced broadening of electronic spectra based on a model that explicitly takes into account the environment embedding the solute. Starting from a classical approximation of the solvent contribution to the spectrum, the broadening arises from the spread of the excitation energies due to the fluctuation of the solvent coordinates, and it is represented as a Gaussian line shape that convolutes the vibronic spectrum of the solute. The latter is computed in harmonic approximation at room temperature with a time-dependent approach. The proposed protocol for the computation of spectral broadening exploits molecular dynamics (MD) simulations performed on the solute-solvent system, keeping the solute degrees of freedom frozen, followed by the computation of the excitation properties with a quantum mechanics/molecular mechanics (QM/MM) approach. The factors that might influence each step of the protocol are analyzed in detail, including the selection of the empirical force field (FF) adopted in the MD simulations and the QM/MM partition of the system to compute the excitation energies. The procedure is applied to a family of coumarin dyes, and the results are compared with experiments and with the predictions of a very recent work (Cerezo et al., Phys. Chem. Chem. Phys. 2015, 17, 11401-11411), where an implicit model was adopted for the solvent. The final spectra of the considered coumarins were obtained without including ad hoc phenomenological parameters and indicate that the broadenings computed with explicit and implicit models both follow the experimental trend, increasing as the polarity change from the initial to the final state increases. More in detail, the implicit model provides larger estimations of the broadening that are closer to the experimental evidence, while explicit models appear to better capture relative differences arising from different solvents or different solutes. Possible inaccuracies of the adopted

  1. Relationship between Fermi Resonance and Solvent Effects

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiu-Lan; LI Dong-Fei; SUN Cheng-Lin; LI Zhan-Long; YANG Guang; ZHOU Mi; LI Zuo-Wei; GAO Shu-Qin

    2011-01-01

    We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations. Also, we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures. It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio, etc., on the other hand, the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.%@@ We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations.Also,we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures.It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio,etc.,on the other hand,the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.

  2. Solvation of rhodamine575 in some solvents

    Science.gov (United States)

    Sharma, Amit

    2016-05-01

    FTIR spectra of Rhodamine575 dye in powder form and in different solvents are reported. Positions of some of the observed FTIR bands show noticeable change in solvents. The bands, which shift, have contributions from the vibrational motion of nitrogen atoms of the ethylamine groups, oxygen atom of the carboxylic group attached to the phenyl ring and oxygen atom of the Xanthene ring.

  3. Solvent effect in the Walden inversion reactions

    Science.gov (United States)

    Jaume, J.; Lluch, J. M.; Oliva, A.; Bertrán, J.

    1984-04-01

    The solvent effect on the fluoride exchange reaction has been studied by means of ab initio calculations using the 3-21G basis set. It is shown that the motion of the solvent molecules is an important part of the reaction coordinate.

  4. SCENARIOS EVALUATION TOOL FOR CHLORINATED SOLVENT MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; Brian02 Looney, B; Michael J. Truex; Charles J. Newell

    2006-08-16

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  5. On the Road to Biopolymer Aerogels—Dealing with the Solvent

    Directory of Open Access Journals (Sweden)

    Raman Subrahmanyam

    2015-12-01

    Full Text Available Aerogels are three-dimensional ultra-light porous structures whose characteristics make them exciting candidates for research, development and commercialization leading to a broad scope of applications ranging from insulation and catalysis to regenerative medicine and pharmaceuticals. Biopolymers have recently entered the aerogel foray. In order to fully realize their potential, progressive strategies dealing with production times and costs reduction must be put in place to facilitate the scale up of aerogel production from lab to commercial scale. The necessity of studying solvent/matrix interactions during solvent exchange and supercritical CO2 drying is presented in this study using calcium alginate as a model system. Four frameworks, namely (a solvent selection methodology based on solvent/polymer interaction; (b concentration gradient influence during solvent exchange; (c solvent exchange kinetics based on pseudo second order model; and (d minimum solvent concentration requirements for supercritical CO2 drying, are suggested that could help assess the role of the solvent in biopolymer aerogel production.

  6. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry.

  7. Assessment of solvents for cellulose dissolution.

    Science.gov (United States)

    Ghasemi, Mohammad; Tsianou, Marina; Alexandridis, Paschalis

    2017-03-01

    A necessary step in the processing of biomass is the pretreatment and dissolution of cellulose. A good solvent for cellulose involves high diffusivity, aggressiveness in decrystallization, and capability of disassociating the cellulose chains. However, it is not clear which of these factors and under what conditions should be improved in order to obtain a more effective solvent. To this end, a newly-developed phenomenological model has been applied to assess the controlling mechanism of cellulose dissolution. Among the findings, the cellulose fibers remain crystalline almost to the end of the dissolution process for decrystallization-controlled kinetics. In such solvents, decreasing the fiber crystallinity, e.g., via pretreatment, would result in a considerable increase in the dissolution rate. Such insights improve the understanding of cellulose dissolution and facilitate the selection of more efficient solvents and processing conditions for biomass. Specific examples of solvents are provided where dissolution is limited due to decrystallization or disentanglement.

  8. Toxic hepatitis in occupational exposure to solvents

    Institute of Scientific and Technical Information of China (English)

    Giulia Malaguarnera; Emanuela Cataudella; Maria Giordano; Giuseppe Nunnari; Giuseppe Chisari; Mariano Malaguarnera

    2012-01-01

    The liver is the main organ responsible for the metabolism of drugs and toxic chemicals,and so is the primary target organ for many organic solvents.Work activities with hepatotoxins exposures are numerous and,moreover,organic solvents are used in various industrial processes.Organic solvents used in different industrial processes may be associated with hepatotoxicity.Several factors contribute to liver toxicity; among these are:species differences,nutritional condition,genetic factors,interaction with medications in use,alcohol abuse and interaction,and age.This review addresses the mechanisms of hepatotoxicity.The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are:inflammation,dysfunction of cytochrome P450,mitochondrial dysfunction and oxidative stress.The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work.

  9. Green-solvent-processable organic solar cells

    Directory of Open Access Journals (Sweden)

    Shaoqing Zhang

    2016-11-01

    Full Text Available Solution-processable organic photovoltaics (OPV has emerged as a promising clean energy-generating technology due to its potential for low-cost manufacturing with a high power/weight ratio. The state-of-the-art OPV devices are processed by hazardous halogenated solvents. Fabricating high-efficiency OPV devices using greener solvents is a necessary step toward their eventual commercialization. In this review, recent research efforts and advances in green-solvent-processable OPVs are summarized, and two basic strategies including material design and solvent selection of light-harvesting layers are discussed. In particular, the most recent green-solvent-processable OPVs with high efficiencies in excess of 9% are highlighted.

  10. Computer Aided Solvent Selection and Design Framework

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Conte, Elisa; Abildskov, Jens

    for indentifying the best candidates depending on different multi-objective criteria namely environment, health, safety, process feasibility and economics. One of the criteria of solvent selection is the environmental impact because of the excessive consumption and utilization in a wide range of industries......Solvents are widely used as a reaction medium, as a reactant or as carrier at some stages of the manufacturing chain in products from the chemical, fine chemical, pharmaceutical, food, and agrochemical industries. Solvent are either required for processing after which they are removed...... or they are part of the final product formulation. Therefore, solvents are playing an important role in product synthesis and formulation, product delivery, separation processes etc [1]. On the other hand, solvent selection and design is a complex problem, which requires decision making in several levels...

  11. [Neurotoxicity of organic solvents--recent findings].

    Science.gov (United States)

    Matsuoka, Masato

    2007-06-01

    In this review, the recent findings of central nervous system (CNS) or peripheral nervous system (PNS) dysfunction induced by occupational exposure to organic solvents are described. While acute, high-level exposure to almost all organic solvents causes the general, nonspecific depression of CNS, it is still not clear whether chronic, low-level occupational exposure causes the chronic neurological dysfunction which has been called "organic solvent syndrome", "painters syndrome", "psycho-organic syndrome" or "chronic solvent encephalopathy". At least at lower than occupational exposure limits, chronic and low-level organic solvent exposure does not appear to cause the "sy mptomatic" neurological dysfunction. The chronic, moderate- to high-level exposure to a few organic solvents (such as carbon disulfide, n-hexane and methyl n-butyl ketone) affects CNS or PNS specifically. The substitutes for chlorofluorocarbons, 2-bromopropane and 1-bromopropane were shown to have the peripheral nerve toxicity in the experimental animals. Shortly after these observations, human cases of 1-bromopropane intoxication with the dysfunction of CNS and PNS were reported in the United States. Neurological abnormalities in workers of a 1-bromopropane factory in China were also reported. Thus, the possible neurotoxicity of newly introduced substitutes for ozone-depleting solvents into the workplace must be considered. Enough evidences indicate that some common solvents (such as toluene and styrene) induce sensorineural hearing loss and acquired color vision disturbances in workers. In some studies using magnetic resonance imaging (MRI), cerebral atrophy, patchy periventricular hyperintensities and hypointensities in the basal ganglia were found in solvent-exposed workers as have been shown in toluene abusers (toluene leukoencephalopathy). Further studies using the neurobehavioral test batteries, neurophysiological measurements and advanced neuroimaging techniques are required to detect the

  12. The chemistry of nonaqueous solvents v.4 solution phenomena and aprotic solvents

    CERN Document Server

    Lagowski, J J

    1976-01-01

    The Chemistry of Nonaqueous Solvents, Volume IV: Solution Phenomena and Aprotic Solvents focuses on the chemistry of nonaqueous solvents, with emphasis on solution phenomena and aprotic solvents such as tetramethylurea, inorganic acid chlorides, cyclic carbonates, and sulfolane. This book is organized into seven chapters and begins with an overview of the theory of electrical conductivity and elementary experimental considerations, along with some of the interesting research on nonaqueous solvents. It then turns to a discussion on hydrogen bonding phenomena in nonaqueous systems as probed

  13. Self-assembled nanostructures of amphiphilic zinc(II) salophen complexes: role of the solvent on their structure and morphology.

    Science.gov (United States)

    Oliveri, Ivan Pietro; Malandrino, Graziella; Di Bella, Santo

    2014-07-14

    This contribution explores the effect of several solvent properties, such as volatility, polarity, and Lewis basicity on the formation of molecular self-assembled nanostructures in the solid state, obtained either by casting of related solutions or by complete solvent evaporation, using seven solvents representative of common classes of coordinating organic solvents, of an amphiphilic Zn(II) Schiff-base complex. In all cases, the existence of well-defined X-ray diffraction patterns, for both the cast and powder samples, indicates a strong tendency towards the molecular self-assembly of such complexes. While nanostructures formed in acetone, THF, pyridine, and DMF have a lamellar organization, those formed in ACN, ethanol, and DMSO exhibit a 2D columnar square structure. Field emission scanning electron microscopy analysis indicates that nanostructures formed in volatile acetone, THF, ACN, and ethanol solvents show a fibrous morphology, while those formed in less volatile pyridine, DMF, and DMSO have a ribbon appearance. Overall, the results indicate that while the formation of such nanostructures is independent of the Lewis basicity of the solvent, the solvent polarity affects their structure - more polar solvents favour higher symmetry structures - and the solvent volatility influences their morphology and ordering in the cast films - lower volatility of the solvent parallels the formation of much more ordered structures. Therefore, the appropriate choice of solvent allows control of the structure, morphology, and ordering of these molecular assemblies.

  14. PARIS II: Computer Aided Solvent Design for Pollution Prevention

    Science.gov (United States)

    This product is a summary of U.S. EPA researchers' work developing the solvent substitution software tool PARIS II (Program for Assisting the Replacement of Industrial Solvents, version 2.0). PARIS II finds less toxic solvents or solvent mixtures to replace more toxic solvents co...

  15. Solvents and Parkinson disease: A systematic review of toxicological and epidemiological evidence

    Energy Technology Data Exchange (ETDEWEB)

    Lock, Edward A., E-mail: e.lock@ljmu.ac.uk [Liverpool John Moores University, School of Pharmacy and Biomolecular Sciences, Byrom Street, Liverpool (United Kingdom); Zhang, Jing [University of Washington, Department of Pathology, School of Medicine, Seattle, WA (United States); Checkoway, Harvey [University of Washington, Department of Environmental and Occupational Health Sciences, Seattle, WA (United States)

    2013-02-01

    Parkinson disease (PD) is a debilitating neurodegenerative motor disorder, with its motor symptoms largely attributable to loss of dopaminergic neurons in the substantia nigra. The causes of PD remain poorly understood, although environmental toxicants may play etiologic roles. Solvents are widespread neurotoxicants present in the workplace and ambient environment. Case reports of parkinsonism, including PD, have been associated with exposures to various solvents, most notably trichloroethylene (TCE). Animal toxicology studies have been conducted on various organic solvents, with some, including TCE, demonstrating potential for inducing nigral system damage. However, a confirmed animal model of solvent-induced PD has not been developed. Numerous epidemiologic studies have investigated potential links between solvents and PD, yielding mostly null or weak associations. An exception is a recent study of twins indicating possible etiologic relations with TCE and other chlorinated solvents, although findings were based on small numbers, and dose–response gradients were not observed. At present, there is no consistent evidence from either the toxicological or epidemiologic perspective that any specific solvent or class of solvents is a cause of PD. Future toxicological research that addresses mechanisms of nigral damage from TCE and its metabolites, with exposure routes and doses relevant to human exposures, is recommended. Improvements in epidemiologic research, especially with regard to quantitative characterization of long-term exposures to specific solvents, are needed to advance scientific knowledge on this topic. -- Highlights: ► The potential for organic solvents to cause Parkinson's disease has been reviewed. ► Twins study suggests etiologic relations with chlorinated solvents and Parkinson's. ► Animal studies with TCE showed potential to cause damage to dopaminergic neurons. ► Need to determine if effects in animals are relevant to human

  16. Predicting the Solubility of Pharmaceutical Cocrystals in Solvent/Anti-Solvent Mixtures

    Directory of Open Access Journals (Sweden)

    Linda Lange

    2016-05-01

    Full Text Available In this work, the solubilities of pharmaceutical cocrystals in solvent/anti-solvent systems were predicted using PC-SAFT in order to increase the efficiency of cocrystal formation processes. Modeling results and experimental data were compared for the cocrystal system nicotinamide/succinic acid (2:1 in the solvent/anti-solvent mixtures ethanol/water, ethanol/acetonitrile and ethanol/ethyl acetate at 298.15 K and in the ethanol/ethyl acetate mixture also at 310.15 K. The solubility of the investigated cocrystal slightly increased when adding small amounts of anti-solvent to the solvent, but drastically decreased for high anti-solvent amounts. Furthermore, the solubilities of nicotinamide, succinic acid and the cocrystal in the considered solvent/anti-solvent mixtures showed strong deviations from ideal-solution behavior. However, by accounting for the thermodynamic non-ideality of the components, PC-SAFT is able to predict the solubilities in all above-mentioned solvent/anti-solvent systems in good agreement with the experimental data.

  17. Preparation of Candesartan and Atorvastatin Nanoparticles by Solvent Evaporation

    Directory of Open Access Journals (Sweden)

    Josef Jampilek

    2012-11-01

    Full Text Available The solubility, absorption and distribution of a drug are involved in the basic aspects of oral bioavailability Solubility is an essential characteristic and influences the efficiency of the drug. Over the last ten years, the number of poorly soluble drugs has steadily increased. One of the progressive ways for increasing oral bioavaibility is the technique of nanoparticle preparation, which allows many drugs to thus reach the intended site of action. Candesartan cilexetil and atorvastatin, belonging to class II of the biopharmaceutical classification system, were chosen as model active pharmaceutical ingredients in this study. Forty samples were prepared either by antisolvent precipitation/solvent evaporation method or by the emulsion/solvent evaporation technique with various commonly used surface-active excipients as nanoparticle stabilizers. All samples were analyzed by means of dynamic light scattering. The particle size of the determined 36 nanoparticle samples was to 574 nm, whereas 32 samples contained nanoparticles of less than 200 nm. Relationships between solvents and excipients used and their amount are discussed. Based on the results the investigated solvent evaporation methods can be used as an effective and an affordable technique for the preparation of nanoparticles.

  18. Solvent effects on photophysical properties of copper and zinc porphyrins

    Institute of Scientific and Technical Information of China (English)

    LI Ye

    2008-01-01

    The photophysics of Zn(tetraphenylporphyrin,TPP), Zn(tetra-2,4,6-trimethylphenyl porphyrin, TMP), Zn (tetra-(o-dichlorophenyl) porphyrin, TPPCI8), Cu(tetraphenylporphyrin,TPP), Cu(tetra-2,4,6-trimethyl-phenyl porphyrin,TMP), and Cu(tetra-(o-dichlorophenyl) porphyrin, TPPCI8,TPPCI8) in several solvents have been investigated on steady state and time-resolved spectroscopy. The Cu(TPPCI8) is normal and shows no evidence of CT transition in the visible or near UV regions in nonpolar solvent. However,Cu(TPPCI8)shows a blue shift in the absorption spectrum and intramolecular CT bands at absorption spectra in polar solvent, which shows a fluorescence maximum emission at 650 nm and 8.4 ns lifetime.The reason can be attributed to two points. Firstly, the increase of solvent polarity can enlarge outer reorganisational energy, which is favorable to reduce the activation free energy of charger-transfer transition based on Marcus theory of electron transfer. Moreover, the internal heavy-atom effect on Cu(TPPCI8) is encouraging to stabilize the 2T1 state also, which increases the possibility of population to CT band from 2T1 state. This result is in accord with an earlier estimate of a 10 ns lifetime and CT absorption at 640 nm bands for the CT state of Cu (Ⅱ) octethylporphyrins. Other possible reasons arousing unusual fluorescence like H-bonding, axial ligands, molecular aggregation are excluded.

  19. Sequentially solution-processed, nanostructured polymer photovoltaics using selective solvents

    KAUST Repository

    Kim, Do Hwan

    2014-01-01

    We demonstrate high-performance sequentially solution-processed organic photovoltaics (OPVs) with a power conversion efficiency (PCE) of 5% for blend films using a donor polymer based on the isoindigo-bithiophene repeat unit (PII2T-C10C8) and a fullerene derivative [6,6]-phenyl-C[71]-butyric acid methyl ester (PC71BM). This has been accomplished by systematically controlling the swelling and intermixing processes of the layer with various processing solvents during deposition of the fullerene. We find that among the solvents used for fullerene deposition that primarily swell but do not re-dissolve the polymer underlayer, there were significant microstructural differences between chloro and o-dichlorobenzene solvents (CB and ODCB, respectively). Specifically, we show that the polymer crystallite orientation distribution in films where ODCB was used to cast the fullerene is broad. This indicates that out-of-plane charge transport through a tortuous transport network is relatively efficient due to a large density of inter-grain connections. In contrast, using CB results in primarily edge-on oriented polymer crystallites, which leads to diminished out-of-plane charge transport. We correlate these microstructural differences with photocurrent measurements, which clearly show that casting the fullerene out of ODCB leads to significantly enhanced power conversion efficiencies. Thus, we believe that tuning the processing solvents used to cast the electron acceptor in sequentially-processed devices is a viable way to controllably tune the blend film microstructure. © 2014 The Royal Society of Chemistry.

  20. Kinetic solvent effects on the reactions of the cumyloxyl radical with tertiary amides. Control over the hydrogen atom transfer reactivity and selectivity through solvent polarity and hydrogen bonding.

    Science.gov (United States)

    Salamone, Michela; Mangiacapra, Livia; Bietti, Massimo

    2015-01-16

    A laser flash photolysis study on the role of solvent effects on hydrogen atom transfer (HAT) from the C-H bonds of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-formylpyrrolidine (FPRD), and N-acetylpyrrolidine (APRD) to the cumyloxyl radical (CumO(•)) was carried out. From large to very large increases in the HAT rate constant (kH) were measured on going from MeOH and TFE to isooctane (kH(isooctane)/kH(MeOH) = 5-12; kH(isooctane)/kH(TFE) > 80). This behavior was explained in terms of the increase in the extent of charge separation in the amides determined by polar solvents through solvent-amide dipole-dipole interactions and hydrogen bonding, where the latter interactions appear to play a major role with strong HBD solvents such as TFE. These interactions increase the electron deficiency of the amide C-H bonds, deactivating these bonds toward HAT to an electrophilic radical such as CumO(•), indicating that changes in solvent polarity and hydrogen bonding can provide a convenient method for deactivation of the C-H bond of amides toward HAT. With DMF, a solvent-induced change in HAT selectivity was observed, suggesting that solvent effects can be successfully employed to control the reaction selectivity in HAT-based procedures for the functionalization of C-H bonds.

  1. 溶剂型涂料中16种有害物质的气相色谱-质谱同时检测方法%Determination of 16 Harmful Substances in Solvent Based Coatings by GC -MS Method

    Institute of Scientific and Technical Information of China (English)

    薛希妹; 薛秋红; 刘心同; 单宝田; 牛增元

    2011-01-01

    A GC - MS method was developed for the determination of 16 kinds of harmful substances (e. g. methanol, volatile halohydrocarbons, benzene homologues, the free toluene diisocyanate and hexane diisocyanate)in solvent based coatings. The extraction and separation efficiencies of targeted compounds by using organic solutions of ethyl acetate, n-hexane, tetrahydrofuran and acetonitrile were investigated. The procedure of sample pre-treatment and the conditions of instruments were optimized. The quantitative analysis of compounds were carried out by using 2-bromopropane and 1, 2,4-trichlorobenzene as the internal standard, and acetonitrile as extraction reagent. The result indicated that the calibration curves of the 16 harmful substances were linear in the range of 5 -200 mg/L with correlation coefficients no less than 0. 999. The spiked recoveries ranged from 80% to 105%with relative standard deviations less than 5.0%. The detection limits ranged from 0. 08 mg/L to 1.41 mg/L. The method was rapid, sensitive and accurate.%建立了溶剂型涂料中16种有害物质(甲醇、卤代烃、苯系物和游离二异氰酸酯)的GC-MS同时检测方法,研究了乙酸乙酯、正己烷、四氢呋喃和乙腈对各有害物质的提取和分离效果,并对样品前处理和色谱条件进行了优化.样品中加入2-溴丙烷和1,2,4-三氯苯作内标,用乙腈超声萃取并经有机膜过滤后,用.GC-MS进行测定,内标法定量.结果表明:16种有害物质在5~200mg/L范围内线性关系良好,相关系数均不低于0.999;样品的加标回收率为80%~105%,相对标准偏差小于5.0%,检出限为0.08~1.41 mg/L.

  2. Determination of poly(epsilon-caprolactone) solubility parameters: application to solvent substitution in a microencapsulation process.

    Science.gov (United States)

    Bordes, C; Fréville, V; Ruffin, E; Marote, P; Gauvrit, J Y; Briançon, S; Lantéri, P

    2010-01-04

    The evolution of regulation on chemical substances (i.e. REACH regulation) calls for the progressive substitution of toxic chemicals in formulations when suitable alternatives have been identified. In this context, the method of Hansen solubility parameters was applied to identify an alternative solvent less toxic than methylene chloride used in a microencapsulation process. During the process based on a multiple emulsion (W/O/W) with solvent evaporation/extraction method, the solvent has to dissolve a polymer, poly(epsilon-caprolactone) (PCL), which forms a polymeric matrix encapsulating or entrapping a therapeutic protein as the solvent is extracted. Therefore the three partial solubility parameters of PCL have been determined by a group contribution method, swelling experiments and turbidimetric titration. The results obtained allowed us to find a solvent, anisole, able to solubilize PCL and to form a multiple emulsion with aqueous solutions. A feasibility test was conducted under standard operating conditions and allowed the production of PCL microspheres.

  3. Water-enhanced solubility of carboxylic acids in organic solvents and its applications to extraction processes

    Energy Technology Data Exchange (ETDEWEB)

    Starr, J.N.; King, C.J.

    1991-11-01

    The solubilities of carboxylic acids in certain organic solvents increase remarkably with an increasing amount of water in the organic phase. This phenomenon leads to a novel extract regeneration process in which the co-extracted water is selectively removed from an extract, and the carboxylic acid precipitates. This approach is potentially advantageous compared to other regeneration processes because it removes a minor component of the extract in order to achieve a large recovery of acid from the extract. Carboxylic acids of interest include adipic acid, fumaric acid, and succinic acid because of their low to moderate solubilities in organic solvents. Solvents were screened for an increase in acid solubility with increased water concentration in the organic phase. Most Lewis-base solvents were found to exhibit this increased solubility phenomena. Solvents that have a carbonyl functional group showed a very large increase in acid solubility. 71 refs., 52 figs., 38 tabs.

  4. Thin-film composite crosslinked polythiosemicarbazide membranes for organic solvent nanofiltration (OSN)

    KAUST Repository

    Aburabie, Jamaliah

    2015-01-01

    In this work we report a new class of solvent stable thin-film composite (TFC) membrane fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate that exhibits superior stability compared with other solvent stable polymeric membranes reported up to now. Integrally skinned asymmetric PTSC membranes were prepared by the phase inversion process and crosslinked with an aromatic bifunctional crosslinker to improve the solvent stability. TFC membranes were obtained via interfacial polymerization using trimesoyl chloride (TMC) and diaminopiperazine (DAP) monomers. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and contact angle measurement.The membranes exhibited high fluxes toward solvents like tetrahydrofuran (THF), dimethylformamide (DMF) and dimethylsulfoxide (DMSO) ranging around 20L/m2 h at 5bar with a molecular weight cut off (MWCO) of around 1000g/mol. The PTSC-based thin-film composite membranes are very stable toward polar aprotic solvents and they have potential applications in the petrochemical and pharmaceutical industry.

  5. Solvent Effect on the Photolysis of Riboflavin.

    Science.gov (United States)

    Ahmad, Iqbal; Anwar, Zubair; Ahmed, Sofia; Sheraz, Muhammad Ali; Bano, Raheela; Hafeez, Ambreen

    2015-10-01

    The kinetics of photolysis of riboflavin (RF) in water (pH 7.0) and in organic solvents (acetonitrile, methanol, ethanol, 1-propanol, 1-butanol, ethyl acetate) has been studied using a multicomponent spectrometric method for the assay of RF and its major photoproducts, formylmethylflavin and lumichrome. The apparent first-order rate constants (k obs) for the reaction range from 3.19 (ethyl acetate) to 4.61 × 10(-3) min(-1) (water). The values of k obs have been found to be a linear function of solvent dielectric constant implying the participation of a dipolar intermediate along the reaction pathway. The degradation of this intermediate is promoted by the polarity of the medium. This indicates a greater stabilization of the excited-triplet states of RF with an increase in solvent polarity to facilitate its reduction. The rate constants for the reaction show a linear relation with the solvent acceptor number indicating the degree of solute-solvent interaction in different solvents. It would depend on the electron-donating capacity of RF molecule in organic solvents. The values of k obs are inversely proportional to the viscosity of the medium as a result of diffusion-controlled processes.

  6. Organic Solvent Tolerant Lipases and Applications

    Directory of Open Access Journals (Sweden)

    Shivika Sharma

    2014-01-01

    Full Text Available Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s could be performed in water-restricted organic media as organic solvent(s not only improve(s the solubility of substrate and reactant in reaction mixture but also permit(s the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented.

  7. Polar Solvents Trigger Formation of Reverse Micelles.

    Science.gov (United States)

    Khoshnood, Atefeh; Firoozabadi, Abbas

    2015-06-09

    We use molecular dynamics simulations and molecular thermodynamics to investigate the formation of reverse micelles in a system of surfactants and nonpolar solvents. Since the early observation of reverse micelles, the question has been whether the existence of polar solvent molecules such as water is the driving force for the formation of reverse micelles in nonpolar solvents. In this work, we use a simple coarse-grained model of surfactants and solvents to show that a small number of polar solvent molecules triggers the formation of large permanent aggregates. In the absence of polar molecules, both the thermodynamic model and molecular simulations show that small aggregates are more populated in the solution and larger ones are less frequent as the system evolves over time. The size and shape of reverse micelles depend on the size of the polar core: the shape is spherical for a large core and ellipsoidal for a smaller one. Using the coarse-grained model, we also investigate the effect of temperature and surfactant tail length. Our results reveal that the number of surfactant molecules in the micelle decreases as the temperature increases, but the average diameter does not change because the size of the polar core remains invariant. A reverse micelle with small polar core attracts fewer surfactants when the tail is long. The uptake of solvent particles by a micelle of longer surfactant tail is less than shorter ones when the polar solvent particles are initially distributed randomly.

  8. Auditory dysfunction associated with solvent exposure

    Directory of Open Access Journals (Sweden)

    Fuente Adrian

    2013-01-01

    Full Text Available Abstract Background A number of studies have demonstrated that solvents may induce auditory dysfunction. However, there is still little knowledge regarding the main signs and symptoms of solvent-induced hearing loss (SIHL. The aim of this research was to investigate the association between solvent exposure and adverse effects on peripheral and central auditory functioning with a comprehensive audiological test battery. Methods Seventy-two solvent-exposed workers and 72 non-exposed workers were selected to participate in the study. The test battery comprised pure-tone audiometry (PTA, transient evoked otoacoustic emissions (TEOAE, Random Gap Detection (RGD and Hearing-in-Noise test (HINT. Results Solvent-exposed subjects presented with poorer mean test results than non-exposed subjects. A bivariate and multivariate linear regression model analysis was performed. One model for each auditory outcome (PTA, TEOAE, RGD and HINT was independently constructed. For all of the models solvent exposure was significantly associated with the auditory outcome. Age also appeared significantly associated with some auditory outcomes. Conclusions This study provides further evidence of the possible adverse effect of solvents on the peripheral and central auditory functioning. A discussion of these effects and the utility of selected hearing tests to assess SIHL is addressed.

  9. Fast molecular beacon hybridization in organic solvents with improved target specificity.

    Science.gov (United States)

    Dave, Neeshma; Liu, Juewen

    2010-12-01

    DNA hybridization is of tremendous importance in biology, bionanotechnology, and biophysics. Molecular beacons are engineered DNA hairpins with a fluorophore and a quencher labeled on each of the two ends. A target DNA can open the hairpin to give an increased fluorescence signal. To date, the majority of molecular beacon detections have been performed only in aqueous buffers. We describe herein DNA detection in nine different organic solvents, methanol, ethanol, isopropanol, acetonitrile, formamide, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethylene glycol, and glycerol, varying each up to 75% (v/v). In comparison with detection in water, the detection in organic solvents showed several important features. First, the molecular beacon hybridizes to its target DNA in the presence of all nine solvents up to a certain percentage. Second, the rate of this hybridization was significantly faster in most organic solvents compared with water. For example, in 56% ethanol, the beacon showed a 70-fold rate enhancement. Third, the ability of the molecular beacon to discriminate single-base mismatch is still maintained. Lastly, the DNA melting temperature in the organic solvents showed a solvent concentration-dependent decrease. This study suggests that molecular beacons can be used for applications where organic solvents must be involved or organic solvents can be intentionally added to improve the molecular beacon performance.

  10. A PFG NMR experiment for translational diffusion measurements in low-viscosity solvents containing multiple resonances

    Science.gov (United States)

    Simorellis, Alana K.; Flynn, Peter F.

    2004-10-01

    Pulsed gradient simulated-echo (PGSE) NMR diffusion measurements provide a facile and accurate means for determining the self-diffusion coefficients for molecules over a wide range of sizes and conditions. The measurement of diffusion in solvents of low intrinsic viscosity is particularly challenging, due to the persistent presence of convection. Although convection can occur in most solvent systems at elevated temperatures, in lower viscosity solvents (e.g., short chain alkanes), convection may manifest itself even at ambient laboratory temperatures. In most circumstances, solvent suppression will also be required, and for solvents that have multiple resonances, effective suppression can likewise represent a substantial challenge. In this article, we report an NMR experiment that combines a double-stimulated echo PFG approach with a WET-based solvent suppression scheme that effectively and simultaneously address the issues of dynamic range and the deleterious effects of convection. The experiment described will be of general benefit to studies aimed at the characterization of diffusion of single molecules directly dissolved in low-viscosity solvents, and should also be of substantial utility in studies of supramolecular assemblies such as reverse-micelles dissolved in apolar solvents.

  11. SOLVENT EXTRACTION OF GINGER OLEORESIN USING ULTRASOUND

    Directory of Open Access Journals (Sweden)

    Normalina Arpi

    2011-11-01

    Full Text Available The use of ultrasound in extraction process creates novel and interesting methodologies, which are oftencomplementary to conventional extraction methods. In the present study, the use of ultrasound to extract oleoresin fromginger (Zingiber officinale R. was investigated. The extraction was performed by using ethanol as solvent in thepresence of ultrasonic irradiations operating at frequency of 42 kHz at extraction temperature of 60 oC. The oleoresinextracted was in the form of dark thick liquid with specific ginger flavor. Based on GC-MS analysis, the use ofultrasound was not give an effect on alteration of main component in ginger oleoresin. The main component inextracted ginger oleoresin was zingerone. Gingerol as one of the pungent principle of the ginger oleoresin was notdetected due to decomposition of gingerol at a temperature above 45 oC. Extraction rate of ultrasound-assistedextraction was about 1.75 times more rapid than a conventional system based on soxhlet. The scanning electronmicroscopy images provided more evidence for the mechanical effects of ultrasound, mainly appearing on cells’ wallsand shown by the destruction of cells, facilitating the release of their contents.

  12. TRUEX process solvent cleanup with solid sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Tse, Pui-Kwan; Reichley-Yinger, L.; Vandegrift, G.F.

    1989-01-01

    Solid sorbents, alumina, silica gel, and Amberlyst A-26 have been tested for the cleanup of degraded TRUEX-NPH solvent. A sodium carbonate scrub alone does not completely remove acidic degradation products from highly degraded solvent and cannot restore the stripping performance of the solvent. By following the carbonate scrub with either neutral alumina or Amberlyst A-26 anion exchange resin, the performance of the TRUEX-NPH is substantially restored. The degraded TRUEX-NPH was characterized before and after treatment by supercritical fluid chromatography. Its performance was evaluated by americium distribution ratios, phase-separation times, and lauric acid distribution coefficients. 17 refs., 2 figs., 5 tabs.

  13. Modeling of Salt Solubilities in Mixed Solvents

    DEFF Research Database (Denmark)

    Chiavone-Filho, O.; Rasmussen, Peter

    2000-01-01

    A method to correlate and predict salt solubilities in mixed solvents using a UNIQUAC+Debye-Huckel model is developed. The UNIQUAC equation is applied in a form with temperature-dependent parameters. The Debye-Huckel model is extended to mixed solvents by properly evaluating the dielectric...... constants and the liquid densities of the solvent media. To normalize the activity coefficients, the symmetric convention is adopted. Thermochemical properties of the salt are used to estimate the solubility product. It is shown that the proposed procedure can describe with good accuracy a series of salt...

  14. Review of recent ORNL studies in solvent cleanup and diluent degradation. Consolidated Fuel-Reprocessing Program

    Energy Technology Data Exchange (ETDEWEB)

    Mailen, J.C.; Tallent, O.K.

    1982-01-01

    Testing of solvent cleanup methods to replace the use of sodium carbonate in the Purex process has been ongoing for several years in order to reduce the quantity of waste sodium nitrate generated and to improve phase separation. Alternate solvent cleanup methods include the use of packed columns of base-treated silica gel or solvent scrubbing with hydrazine oxalate. Degradation of the diluent was shown to generate long-chain organic acids which appear to be the major culprits in the phase separation problems encountered in sodium carbonate scrubbers. Solvent scrubbing with hydrazine oxalate gives improved phase separations. Solvent cleanup in columns packed with base-treated silica gel avoids the phase separation problem since a dispersable aqueous phase is not present. Removals of TBP degradation products and metal-ion complexes by sodium carbonate, hydrazine salts, or by packed beds of base-treated silica gel are all satisfactory. Solvent scrubbing by hydrazine oxalate solutions is the prime candidate for solvent cleanup in fuel reprocessing plants.

  15. Interdependence of conformational and chemical reaction dynamics during ion assembly in polar solvents.

    Science.gov (United States)

    Ji, Minbiao; Hartsock, Robert W; Sun, Zheng; Gaffney, Kelly J

    2011-10-01

    We have utilized time-resolved vibrational spectroscopy to study the interdependence of the conformational and chemical reaction dynamics of ion assembly in solution. We investigated the chemical interconversion dynamics of the LiNCS ion pair and the (LiNCS)(2) ion-pair dimer, as well as the spectral diffusion dynamics of these ionic assemblies. For the strongly coordinating Lewis base solvents benzonitrile, dimethyl carbonate, and ethyl acetate, we observe Li(+) coordination by both solvent molecules and NCS(-) anions, while the weak Lewis base solvent nitromethane shows no evidence for solvent coordination of Li(+) ions. The strong interaction between the ion-pair dimer structure and the Lewis base solvents leads to ion-pair dimer solvation dynamics that proceed more slowly than the ion-pair dimer dissociation. We have attributed the slow spectral diffusion dynamics to electrostatic reorganization of the solvent molecules coordinated to the Li(+) cations present in the ion-pair dimer structure and concluded that the dissociation of ion-pair dimers depends more critically on longer length scale electrostatic reorganization. This unusual inversion of the conformational and chemical reaction rates does not occur for ion-pair dimer dissociation in nitromethane or for ion pair association in any of the solvents.

  16. First title: Ionic liquids-useful reaction green solvents for the future Second title: ionic liquids are the replacements for environmentally damaging solvents in a wide range of chemical processes.

    OpenAIRE

    K.Vijaya Bhaskar

    2012-01-01

    Ionic liquids (IL) represent fascinating new class of solvents with unusual physical and chemical properties; low melting salts (up to 1000C). The main driving force for research in this area is the need to find replacement for environmentally damaging solvents in a wide range of chemical processes. To date, most chemical reactions have been carried out in molecular solvents. For the past twenty years, most of our understanding of our chemistry has been based upon the behavior of molecules in...

  17. A Peptide Amphiphile Organogelator of Polar Organic Solvents

    Science.gov (United States)

    Rouse, Charlotte K.; Martin, Adam D.; Easton, Christopher J.; Thordarson, Pall

    2017-01-01

    A peptide amphiphile is reported, that gelates a range of polar organic solvents including acetonitrile/water, N,N-dimethylformamide and acetone, in a process dictated by β-sheet interactions and facilitated by the presence of an alkyl chain. Similarities with previously reported peptide amphiphile hydrogelators indicate analogous underlying mechanisms of gelation and structure-property relationships, suggesting that peptide amphiphile organogel design may be predictably based on hydrogel precedents. PMID:28255169

  18. Organic fragments from graphene oxide: Isolation, characterization and solvent effects

    Indian Academy of Sciences (India)

    Ravula Thirupathi; Y Jayasubba Reddy; Erode N Prabhakaran; Hanudatta S Atreya

    2014-05-01

    As-prepared graphene oxide (GO) contains oxidative debris which can be washed using basic solutions. We present the isolation and characterization of these debris. Dynamic light scattering (DLS) is used to monitor the separation of the debris in various solvents in the presence of different protic and aprotic alkylamino bases. The study reveals that the debris are rich in carbonyl functional groups and water is an essential component for separation and removal of the debris from GO under oxidative reaction conditions.

  19. Predicting the Activity Coefficients of Free-Solvent for Concentrated Globular Protein Solutions Using Independently Determined Physical Parameters

    OpenAIRE

    McBride, Devin W; Rodgers, Victor G. J.

    2013-01-01

    The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent...

  20. "Solvent Effects" in 1H NMR Spectroscopy.

    Science.gov (United States)

    Cavaleiro, Jose A. S.

    1987-01-01

    Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

  1. Solvent-Free Synthesis of New Coumarins

    Directory of Open Access Journals (Sweden)

    Redah I. Al-Bayati

    2012-01-01

    Full Text Available A solvent-free synthesis of five series of coumarin derivatives using microwave assistant is presented herein. The synthesized compounds are fully characterized by UV-VIS, FT-IR, and NMR spectroscopy.

  2. Water as a Solvent for Life

    Science.gov (United States)

    Pohorille, Andrew; Pratt, Lawrence R.

    2015-01-01

    "Follow the water" is our basic strategy in searching for life in the universe. The universality of water as the solvent for living systems is usually justified by arguing that water supports the rich organic chemistry that seeds life, but alternative chemistries are possible in other organic solvents. Here, other, essential criteria for life that have not been sufficiently considered so far, will be discussed.

  3. Competitive solvent-molecule interactions govern primary processes of diphenylcarbene in solvent mixtures

    Science.gov (United States)

    Knorr, Johannes; Sokkar, Pandian; Schott, Sebastian; Costa, Paolo; Thiel, Walter; Sander, Wolfram; Sanchez-Garcia, Elsa; Nuernberger, Patrick

    2016-10-01

    Photochemical reactions in solution often proceed via competing reaction pathways comprising intermediates that capture a solvent molecule. A disclosure of the underlying reaction mechanisms is challenging due to the rapid nature of these processes and the intricate identification of how many solvent molecules are involved. Here combining broadband femtosecond transient absorption and quantum mechanics/molecular mechanics simulations, we show for one of the most reactive species, diphenylcarbene, that the decision-maker is not the nearest solvent molecule but its neighbour. The hydrogen bonding dynamics determine which reaction channels are accessible in binary solvent mixtures at room temperature. In-depth analysis of the amount of nascent intermediates corroborates the importance of a hydrogen-bonded complex with a protic solvent molecule, in striking analogy to complexes found at cryogenic temperatures. Our results show that adjacent solvent molecules take the role of key abettors rather than bystanders for the fate of the reactive intermediate.

  4. Solvent Hold Tank Sample Results For MCU-15-710-711-712: June 2015 Monthly Sample

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-07

    Savannah River National Laboratory (SRNL) received one set of Solvent Hold Tank (SHT) samples (MCU-15-710, MCU-15-711, and MCU-15-712), pulled on 06/15/2015 for analysis. The samples were combined and analyzed for composition. Analysis of the composite sample MCU-15-710-711-712 indicated a low concentration (~ 55 % of nominal) of the suppressor (TiDG) and concentrations of the extractant (MaxCalix), and of the modifier (Cs-7SB) in the solvent that were slightly lower than nominal. This analysis confirms the addition of TiDG, MaxCalix, and modifier (92 % of nominal) to the solvent in February 2015. Based on the current monthly sample, the levels of TiDG, MaxCalix, and modifier were sufficient when this solvent sample was collected from MCU. A higher cesium concentration (9.3 E6 dpm/mL) was observed in this sample relative to recent samples. In the past, this level of cesium appeared to correlate with upsets in the MCU operation. It is not known at this time the reason for the higher cesium level in this solvent. No impurities above the 1000 ppm level were found in this solvent by the Semi-Volatile Organic Analysis (SVOA). In addition, the sample contains up to 10.4 micrograms of mercury per gram of solvent (or 8.7 µg/mL). A relatively large cesium concentration (9.3 E 6 dpm/mL) was measured in this solvent and it may indicate poor cesium stripping. The laboratory will continue to monitor the quality of the solvent in particular for any new impurities or degradation of the solvent components.

  5. Multicomponent solubility parameters for single-walled carbon nanotube-solvent mixtures.

    Science.gov (United States)

    Bergin, Shane D; Sun, Zhenyu; Rickard, David; Streich, Philip V; Hamilton, James P; Coleman, Jonathan N

    2009-08-25

    We have measured the dispersibility of single-walled carbon nanotubes in a range of solvents, observing values as high as 3.5 mg/mL. By plotting the nanotube dispersibility as a function of the Hansen solubility parameters of the solvents, we have confirmed that successful solvents occupy a well-defined range of Hansen parameter space. The level of dispersibility is more sensitive to the dispersive Hansen parameter than the polar or H-bonding Hansen parameter. We estimate the dispersion, polar, and hydrogen bonding Hansen parameter for the nanotubes to be = 17.8 MPa(1/2), = 7.5 MPa(1/2), and = 7.6 MPa(1/2). We find that the nanotube dispersibility in good solvents decays smoothly with the distance in Hansen space from solvent to nanotube solubility parameters. Finally, we propose that neither Hildebrand nor Hansen solubility parameters are fundamental quantities when it comes to nanotube-solvent interactions. We show that the previously calculated dependence of nanotube Hildebrand parameter on nanotube diameter can be reproduced by deriving a simple expression based on the nanotube surface energy. We show that solubility parameters based on surface energy give equivalent results to Hansen solubility parameters. However, we note that, contrary to solubility theory, a number of nonsolvents for nanotubes have both Hansen and surface energy solubility parameters similar to those calculated for nanotubes. The nature of the distinction between solvents and nonsolvents remains to be fully understood.

  6. Solvent dependent photophysical properties of dimethoxy curcumin

    Science.gov (United States)

    Barik, Atanu; Indira Priyadarsini, K.

    2013-03-01

    Dimethoxy curcumin (DMC) is a methylated derivative of curcumin. In order to know the effect of ring substitution on photophysical properties of curcumin, steady state absorption and fluorescence spectra of DMC were recorded in organic solvents with different polarity and compared with those of curcumin. The absorption and fluorescence spectra of DMC, like curcumin, are strongly dependent on solvent polarity and the maxima of DMC showed red shift with increase in solvent polarity function (Δf), but the above effect is prominently observed in case of fluorescence maxima. From the dependence of Stokes' shift on solvent polarity function the difference between the excited state and ground state dipole moment was estimated as 4.9 D. Fluorescence quantum yield (ϕf) and fluorescence lifetime (τf) of DMC were also measured in different solvents at room temperature. The results indicated that with increasing solvent polarity, ϕf increased linearly, which has been accounted for the decrease in non-radiative rate by intersystem crossing (ISC) processes.

  7. Influence of solvent polarity on preferential solvation of molecular recognition probes in solvent mixtures.

    Science.gov (United States)

    Amenta, Valeria; Cook, Joanne L; Hunter, Christopher A; Low, Caroline M R; Vinter, Jeremy G

    2012-12-13

    The association constants for formation of 1:1 complexes between a H-bond acceptor, tri-n-butylphosphine oxide, and a H-bond donor, 4-phenylazophenol, have been measured in a range of different solvent mixtures. Binary mixtures of n-octane and a more polar solvent (ether, ester, ketone, nitrile, sulfoxide, tertiary amide, and halogenated and aromatic solvents) have been investigated. Similar behavior was observed in all cases. When the concentration of the more polar solvent is low, the association constant is identical to that observed in pure n-octane. Once a threshold concentration of the more polar solvent in reached, the logarithm of the association constant decreases in direct proportion to the logarithm of the concentration of the more polar solvent. This indicates that one of the two solutes is preferentially solvated by the more polar solvent, and it is competition with this solvation equilibrium that determines the observed association constant. The concentration of the more polar solvent at which the onset of preferential solvation takes place depends on solvent polarity: 700 mM for toluene, 60 mM for 1,1,2,2-tetrachloroethane, 20 mM for the ether, ester, ketone, and nitrile, 0.2 mM for the tertiary amide, and 0.1 mM for the sulfoxide solvents. The results can be explained by a simple model that considers only pairwise interactions between specific sites on the surfaces of the solutes and solvents, which implies that the bulk properties of the solvent have little impact on solvation thermodynamics.

  8. Caustic-Side Solvent Extraction: Chemical and Physical Properties of the Optimized Solvent

    Energy Technology Data Exchange (ETDEWEB)

    Delmau, L.H.

    2002-10-08

    This work was undertaken to optimize the solvent used in the Caustic Side Solvent Extraction (CSSX) process and to measure key chemical and physical properties related to its performance in the removal of cesium from the alkaline high-level salt waste stored in tanks at the Savannah River Site. The need to adjust the solvent composition arose from the prior discovery that the previous baseline solvent was supersaturated with respect to the calixarene extractant. The following solvent-component concentrations in Isopar{reg_sign} L diluent are recommended: 0.007 M calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) extractant, 0.75 M 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) phase modifier, and 0.003 M tri-n-octylamine (TOA) stripping aid. Criteria for this selection included BOBCalixC6 solubility, batch cesium distribution ratios (D{sub Cs}), calculated flowsheet robustness, third-phase formation, coalescence rate (dispersion numbers), and solvent density. Although minor compromises within acceptable limits were made in flowsheet robustness and solvent density, significant benefits were gained in lower risk of third-phase formation and lower solvent cost. Data are also reported for the optimized solvent regarding the temperature dependence of D{sub Cs} in extraction, scrubbing, and stripping (ESS); ESS performance on recycle; partitioning of BOBCalixC6, Cs-7SB, and TOA to aqueous process solutions; partitioning of organic anions; distribution of metals; solvent phase separation at low temperatures; solvent stability to elevated temperatures; and solvent density and viscosity. Overall, the technical risk of the CSSX process has been reduced by resolving previously identified issues and raising no new issues.

  9. Nitromethane as solvent in capillary electrophoresis.

    Science.gov (United States)

    Subirats, Xavier; Porras, Simo P; Rosés, Martí; Kenndler, Ernst

    2005-06-24

    Nitromethane has several properties that make it an interesting solvent for capillary electrophoresis especially for lipophilic analytes that are not sufficiently soluble in water: freezing and boiling points are suitable for laboratory conditions, low viscosity leads to favourable electrophoretic mobilities, or an intermediate dielectric constant enables dissolution of electrolytes. In the present work we investigate the change of electrophoretically relevant analyte properties - mobilities and pKa values - in nitromethane in dependence on the most important experimental conditions determined by the background electrolyte: the ionic strength, I, and the pH. It was found that the mobility decreases with increasing ionic strength (by, e.g. up to 30% from I = 0 to 50 mmol/L) according to theory. An appropriate pH scale is established by the aid of applying different concentration ratios of a buffer acid with known pKa and its conjugate base. The mobility of the anionic analytes (from weak neutral acids) depends on the pH with the typical sigmoidal curve in accordance with theory. The pKa of neutral acids derived from these curves is shifted by as much as 14 pK units in nitromethane compared to water. Both findings confirm the agreement of the electrophoretic behaviour of the analytes with theories of electrolyte solutions. Separation of several neutral analytes was demonstrated upon formation of charged complexes due to heteroconjugation with chloride as ionic constituent of the background electrolyte.

  10. Enantioselective solvent-free Robinson annulation reactions

    Indian Academy of Sciences (India)

    D Rajagopal; R Narayanan; S Swaminathan

    2001-06-01

    The enantioselective cyclization of the prochiral cyclic substrates 1 to 7 and 26, can be carried out in the neat using -proline as catalyst. The substrates 18 to 22 and 27 could not be cyclized with S-proline but could be cyclized with a mixture of -phenylalanine and -camphorsulphonic acid. The enantioselective cyclization of prochiral acyclic triones 45 and 47 and also the racemic tricarbonyl compounds 54 to 57 could also be carried out in the \\text{neat} using -proline as catalyst. The optically active enediones obtained in the above cyclizations could also be obtained directly from 1,3-diones or 2-hydroxymethylene cycloalkanones in a one-pot reaction with methyl vinyl ketone (MVK) and S-proline in the absence of solvents. 13C NMR studies of the one-pot synthesis of S-11 and S-14 reveal that the annulations involve initial formation of an acid-base complex followed by a Michael reaction and then an enantioselective cyclization. Such enantioselective cyclizations probably occur on the surface of -proline crystals.

  11. 1/6TH SCALE STRIP EFFLUENT FEED TANK-MIXING RESULTS USING MCU SOLVENT

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E

    2006-02-01

    The purpose of this task was to determine if mixing was an issue for the entrainment and dispersion of the Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) solvent in the Defense Waste Processing Facility (DWPF) Strip Effluent Feed Tank (SEFT). The MCU strip effluent stream containing the Cs removed during salt processing will be transferred to the DWPF for immobilization in HLW glass. In lab-scale DWPF chemical process cell testing, mixing of the solvent in the dilute nitric acid solution proved problematic, and the Savannah River National Laboratory (SRNL) was requested to perform scaled SEFT mixing tests to evaluate whether the problem was symptomatic of the lab-scale set-up or of the solvent. The solvent levels tested were 228 and 235 ppm, which represented levels near the estimated DWPF solvent limit of 239 ppm in 0.001M HNO{sub 3} solution. The 239 ppm limit was calculated by Norato in X-CLC-S-00141. The general approach for the mixing investigation was to: (1) Investigate the use of fluorescent dyes to aid in observing the mixing behavior. Evaluate and compare the physical properties of the fluorescent dyed MCU solvents to the baseline Oak Ridge CSSX solvent. Based on the data, use the dyed MCU solvent that best approximates the physical properties. (2) Use approximately a 1/6th linear scale of the SEFT to replicate the internal configuration for DWPF mixing. (3) Determine agitator speed(s) for scaled testing based on the DWPF SEFT mixing speed. (4) Perform mixing tests using the 1/6th SEFT and determine any mixing issues (entrainment/dispersion, accumulation, adhesion) through visual observations and by pulling samples to assess uniformity. The mixing tests used MCU solvent fabricated at SRNL blended with Risk Reactor DFSB-K43 fluorescent dye. This dyed SRNL MCU solvent had equivalent physical properties important to mixing as compared to the Oak Ridge baseline solvent, blended easily with the MCU solvent, and provided an excellent visual aid.

  12. The use of environmentally sustainable bio-derived solvents in solvent extraction applications-A review

    Institute of Scientific and Technical Information of China (English)

    Zheng Li; Kathryn H. Smith; Geoffrey W. Stevens

    2016-01-01

    Replacement of volatile organic compounds (VOCs) by greener or more environmental y sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as wel as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over con-ventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction pilot plant studies.

  13. CHEMICAL STABILITY OF POLYPHENYLENE SULFIDE IN THE NEXT GENERATION SOLVENT FOR CAUSTIC-SIDE SOLVENT EXTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.; Fink, S.

    2011-12-08

    The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. For simplicity, this solvent is referred to as the Next Generation Solvent (NGS). The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The initial deployment target envisioned for the technology was within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with polyphenylene sulfide (PPS), the polymer used in the coalescers within MCU. This report provides the data from exposing PPS polymer to NGS. The test was conducted over a three month period. PPS is remarkably stable in the presence of the next generation solvent. Testing showed no indication of swelling or significant leaching. Preferential sorption of the Modifier on PPS was observed but the same behavior occurs with the baseline solvent. Therefore, PPS coalescers exposed to the NGS are expected to perform comparably to those in contact with the baseline solvent.

  14. Influence of Energy on Solvent Diffusion in Polymer/Solvent Systems

    Institute of Scientific and Technical Information of China (English)

    HUHuijun; JIANGWenhua; 等

    2002-01-01

    The Vrentas-Duda free-volume theory has been extensively used to correlate or predict the solvent diffusion coefficient of a polymer/solvent system.The energy term in the free volume diffusion equation is difficult to estimate,so the energy term was usually neglected in previous predictive versions of the free volume diffusion coefficient equation.Recent studies show that the energy effect is very important even above the glass transition temperature of the system. In this paper, a new evaluation method of the energy term is proposed,that is the diffusion energy at different solvent concentrations is assumed to be a linear function of the solvent diffusion energy in pure solvents and that in polymers under the condition that the solvent in infinite dilution.By taking consideration of the influence of energy on the solvent diffustion,the prediction of solvent diffusion coefficient was preformed for three polymer/solvent systems over a wide range of concentrations and temperatures.The results show an improvement on the predictive capability of the free volume diffusion theory.

  15. Selective recognition of sulfate anions in a 95% ethanol solvent with a simple neutral salicylaldehyde dansyl hydrazine Schiff base tuned by Brønsted-Lowry acid-base reaction

    Science.gov (United States)

    Wei, Gao-Ning; Zhang, Jing-Li; Jia, Cang; Fan, Wei-Zhen; Lin, Li-Rong

    2014-07-01

    A new Schiff base compound, 5-(dimethylamino)-N‧-(2-hydroxybenzylidene)naphthalene-1-sulfonohydrazide (R), has been synthesized, characterized, and employed as a selective fluorescence receptor for the recognition of sulfate anions. UV-vis absorption, fluorescence emission, 1H NMR spectra and DFT calculation studies on the system have been carried out to determine the nature of the interactions between R and anions. The results reveal that the deprotonation of the phenol without the need of a strong base leads to the formation of a hydrogen-bonding complex with a sbnd SO2sbnd NHsbnd group, which is responsible for the spectra changes. The deprotonation process for the selectivity recognition of sulfate can be tuned by the Brønsted-Lowry acid-base reaction in nonaqueous solutions, revealing that suitable phenolic hydroxyl acidity is the key factor for anion recognition selectivity.

  16. Computational simulations on the fish-type-Ⅱ antifreeze protein-ice-solvent system

    Institute of Scientific and Technical Information of China (English)

    LIU Kai; WANG Yan; TAN Hongwei; CHEN Guangju; TONG Zhenhe

    2007-01-01

    Based on the computational simulation with the vacuum environment for the fish-type-Ⅱ antifreeze proteinice-solvent (water)system,the multi-complex system of the antifreeze protein-ice-water has been constructed and calculated.We have studied the interaction of such proteinice system with water solvent through the dynamics simulation with 350 ps.By employing the Molecular Dynamics simulation and semi-empirical method calculation,we have further investigated the interface properties of the antifreeze protein and ice crystal combined system.Consequently,a water solvent affects significantly the properties of this combined system.

  17. Recovery of dilute acetone-butanol-ethanol (ABE) solvents from aqueous solutions via membrane distillation

    Energy Technology Data Exchange (ETDEWEB)

    Banat, F.A.; Al-Shannag, M. [Jordan Univ. of Science and Technology, Irbid (Jordan). Dept. of Chemical Engineering

    2000-12-01

    The simultaneous recovery of dilute acetone-butanol-ethanol (ABE) solvents from aqueous solutions by air gap membrane distillation was theoretically assessed. A previously developed and validated Stefan-Maxwell based mathematical model was used for this purpose. It was found that membrane distillation could successfully be used for the recovery of these solvents. Interestingly it was found that butanol could be separated with the highest selectivity and flux though it has the highest boiling point. The effect of operating conditions such as feed and cooling surface temperatures, air gap width, and individual component concentration on the flux and selectivity of these solvents was examined and discussed in this paper. (orig.)

  18. NMR Chemical Shift Ranges of Urine Metabolites in Various Organic Solvents

    Directory of Open Access Journals (Sweden)

    Benjamin Görling

    2016-09-01

    Full Text Available Signal stability is essential for reliable multivariate data analysis. Urine samples show strong variance in signal positions due to inter patient differences. Here we study the exchange of the solvent of a defined urine matrix and how it affects signal and integral stability of the urinary metabolites by NMR spectroscopy. The exchange solvents were methanol, acetonitrile, dimethyl sulfoxide, chloroform, acetone, dichloromethane, and dimethyl formamide. Some of these solvents showed promising results with a single batch of urine. To evaluate further differences between urine samples, various acid, base, and salt solutions were added in a defined way mimicking to some extent inter human differences. Corresponding chemical shift changes were monitored.

  19. Implementations of advisory system for the solvent selection of carbon dioxide removal processes

    Energy Technology Data Exchange (ETDEWEB)

    Chan, C.; Lau, P. [Regina Univ., SK (Canada)

    1997-12-31

    The Solvent Selection Advisory System (SSAS) is a decision support system for aiding users in the preliminary selection of optimal solvents for carbon dioxide removal processes given different user specification and plant conditions. This paper describes an inference-network representation of the Solvent Selection Advisory System which has been previously implemented as a rule-based system. Two expert system shells, G2 and GDA from Gensym Corp. are used, and the implementations on a two shell are compared. Some advantages and disadvantages in the two representation approaches are discussed. (Author)

  20. NMR Chemical Shift Ranges of Urine Metabolites in Various Organic Solvents

    Science.gov (United States)

    Görling, Benjamin; Bräse, Stefan; Luy, Burkhard

    2016-01-01

    Signal stability is essential for reliable multivariate data analysis. Urine samples show strong variance in signal positions due to inter patient differences. Here we study the exchange of the solvent of a defined urine matrix and how it affects signal and integral stability of the urinary metabolites by NMR spectroscopy. The exchange solvents were methanol, acetonitrile, dimethyl sulfoxide, chloroform, acetone, dichloromethane, and dimethyl formamide. Some of these solvents showed promising results with a single batch of urine. To evaluate further differences between urine samples, various acid, base, and salt solutions were added in a defined way mimicking to some extent inter human differences. Corresponding chemical shift changes were monitored. PMID:27598217

  1. Bio-refinery of orange peels waste: a new concept based on integrated green and solvent free extraction processes using ultrasound and microwave techniques to obtain essential oil, polyphenols and pectin.

    Science.gov (United States)

    Boukroufa, Meryem; Boutekedjiret, Chahrazed; Petigny, Loïc; Rakotomanomana, Njara; Chemat, Farid

    2015-05-01

    In this study, extraction of essential oil, polyphenols and pectin from orange peel has been optimized using microwave and ultrasound technology without adding any solvent but only "in situ" water which was recycled and used as solvent. The essential oil extraction performed by Microwave Hydrodiffusion and Gravity (MHG) was optimized and compared to steam distillation extraction (SD). No significant changes in yield were noticed: 4.22 ± 0.03% and 4.16 ± 0.05% for MHG and SD, respectively. After extraction of essential oil, residual water of plant obtained after MHG extraction was used as solvent for polyphenols and pectin extraction from MHG residues. Polyphenols extraction was performed by ultrasound-assisted extraction (UAE) and conventional extraction (CE). Response surface methodology (RSM) using central composite designs (CCD) approach was launched to investigate the influence of process variables on the ultrasound-assisted extraction (UAE). The statistical analysis revealed that the optimized conditions of ultrasound power and temperature were 0.956 W/cm(2) and 59.83°C giving a polyphenol yield of 50.02 mgGA/100 g dm. Compared with the conventional extraction (CE), the UAE gave an increase of 30% in TPC yield. Pectin was extracted by conventional and microwave assisted extraction. This technique gives a maximal yield of 24.2% for microwave power of 500 W in only 3 min whereas conventional extraction gives 18.32% in 120 min. Combination of microwave, ultrasound and the recycled "in situ" water of citrus peels allow us to obtain high added values compounds in shorter time and managed to make a closed loop using only natural resources provided by the plant which makes the whole process intensified in term of time and energy saving, cleanliness and reduced waste water.

  2. Low density solvent based dispersive liquid-liquid microextraction with gas chromatography-electron capture detection for the determination of cypermethrin in tissues and blood of cypermethrin treated rats.

    Science.gov (United States)

    Mudiam, Mohana Krishna Reddy; Jain, Rajeev; Maurya, Shailendra Kumar; Khan, Haider A; Bandyopadhyay, Sanghamitra; Murthy, R C

    2012-05-01

    A simple and rapid method to determine the cypermethrin (CYP) insecticide in rat tissues (kidney, liver and brain) and blood has been developed for the first time using low density solvent-dispersive liquid-liquid microextraction (LDS-DLLME) followed by gas chromatography-electron capture detector (GC-ECD) analysis. Initially, tissue samples containing CYP were homoginized in acetone. Subsequently, homogenate was mixed with n-hexane (extraction solvent) and the mixture was rapidly injected into water. The upper n-hexane layer was collected in a separate microtube and injected into GC-ECD for analysis. Blood samples were diluted with ultrapure water and subjected to DLLME through similar procedure. Parameters such as type and volume of disperser and extraction solvent, salting out effect and extraction time, which can affect the extraction efficiency of DLLME, were optimized. Method was validated by investigating linearity, precision, recovery, limit of detection (LOD) and quantification (LOQ). LODs in tissue were in the range of 0.043-0.314 ng mg(-1) and for blood it was 8.6 ng mL(-1) with a signal to noise ratio of 3:1. LOQs in tissue were in the range of 0.143-1.03 ng mg(-1) and for blood it was 28.3 ng mL(-1) with a signal to noise ratio of 10:1. Mean recoveries of CYP at three different concentation levels in all the matrices were found to be in the range of 81.6-103.67%. The results show that, LDS-DLLME coupled with GC-ECD offers a simple, rapid and efficient technique for extraction and determination of CYP in rat tissues and blood samples, which in turn would be useful for toxicological studies of CYP.

  3. Stability of the Caustic-Side Solvent Extraction (CSSX) Process Solvent: Effect of High Nitrite on Solvent Nitration

    Energy Technology Data Exchange (ETDEWEB)

    Bonnesen, P.V.

    2002-06-26

    The purpose of this investigation was to determine whether nitrated organic compounds could be formed during operation of the Caustic-Side Solvent Extraction (CSSX) process, and whether such compounds would present a safety concern. The CSSX process was developed to remove cesium from alkaline high-level salt waste stored at the US Department of Energy Savannah River Site (SRS). The solvent is composed of the cesium extractant calix[4]arene-bis-(4-tert-octylbenzo-crown-6) (BOBCalixC6), a fluorinated alcohol phase modifier, tri-n-octylamine (TOA), and an isoparaffinic diluent (Iospar{reg_sign}). During the CSSX process, the solvent is expected to be exposed to high concentrations of nitrate and nitrite dissolved in the alkaline waste feed. The solvent will also be exposed to dilute (50 mM) nitric acid solutions containing low concentrations of nitrite during scrubbing, followed by stripping with 1 mM nitric acid. The solvent is expected to last for one year of plant operation, and the temperatures the solvent may experience during the process could range from as low as 15 C to as high as 35 C. Excursions from standard process conditions could result in the solvent experiencing higher temperatures, as well as concentrations of nitrate, nitrite, and most importantly nitric acid, that exceed normal operating conditions. Accordingly, conditions may exist where nitration reactions involving the solvent components, possibly leading to other chemical reactions stemming from nitration reactions, could occur. To model such nitration reactions, the solvent was exposed to the types of nitrate- and nitrite-containing solutions that might be expected to be encountered during the process (even under off-normal conditions), as a function of time, temperature, and concentration of nitrate, nitrite, and nitric acid. The experiments conducted as part of this report were designed to examine the more specific effect that high nitrite concentrations could have on forming nitrated

  4. Anomalous excited-state dynamics of lucifer yellow CH in solvents of high polarity: evidence for an intramolecular proton transfer.

    Science.gov (United States)

    Panda, Debashis; Mishra, Padmaja P; Khatua, Saumyakanti; Koner, Apurba L; Sunoj, Raghavan B; Datta, Anindya

    2006-05-04

    The photophysics of the fluorescent probe Lucifer yellow CH has been investigated using fluorescence spectroscopic and computational techniques. The nonradiative rate is found to pass through a minimum in solvents of intermediate empirical polarity. This apparently anomalous behavior is rationalized by considering the possibility of predominance of different kinds of nonradiative processes, viz. intersystem crossing (ISC) and excited-state proton transfer (ESPT), in solvents of low and high empirical polarity, respectively. The feasibility of the proton transfer is examined by the structure determined by the density functional theory (DFT) calculations. The predicted energy levels based on the time-dependent density functional theory (TD-DFT) method in the gas phase identifies the energy gap between the S(1) and nearest triplet state to be close enough to facilitate ISC. Photophysical investigation in solvent mixtures and in deuterated solvents clearly indicates the predominance of the solvent-mediated intramolecular proton transfer in the excited state of the fluorophore in protic solvents.

  5. Molecular Modeling of Enzyme Dynamics Towards Understanding Solvent Effects

    DEFF Research Database (Denmark)

    Wedberg, Nils Hejle Rasmus Ingemar

    the concentration of water in a region of the simulation box far from the protein surface. In order to evaluate the corresponding activity, a previously developed methodology based on fluctuation solution theory is employed to compute the excess Gibbs energy of the water/organic solvent mixture. This requires...... that separate simulations of this mixture are carried out at different compositions, and that the total correlation function integrals, i.e. spatial integrals of the pair radial distribution functions (RDFs), are evaluated. A main challenge is that the total correlation function integrals do not converge within...... integration, while for small systems, it seems to be even better. The method is applied to compute the excess Gibbs energy of the mixtures of water and organic solvents used in the simulations of CALB. This allows to determine the water activity of the simulated systems and thus to compare protein properties...

  6. Solvents' Critical Role in Nonaqueous Lithium-Oxygen Battery Electrochemistry.

    Science.gov (United States)

    McCloskey, B D; Bethune, D S; Shelby, R M; Girishkumar, G; Luntz, A C

    2011-05-19

    Among the many important challenges facing the development of Li-air batteries, understanding the electrolyte's role in producing the appropriate reversible electrochemistry (i.e., 2Li(+) + O2 + 2e(-) ↔ Li2O2) is critical. Quantitative differential electrochemical mass spectrometry (DEMS), coupled with isotopic labeling of oxygen gas, was used to study Li-O2 electrochemistry in various solvents, including carbonates (typical Li ion battery solvents) and dimethoxyethane (DME). In conjunction with the gas-phase DEMS analysis, electrodeposits formed during discharge on Li-O2 cell cathodes were characterized using ex situ analytical techniques, such as X-ray diffraction and Raman spectroscopy. Carbonate-based solvents were found to irreversibly decompose upon cell discharge. DME-based cells, however, produced mainly lithium peroxide on discharge. Upon cell charge, the lithium peroxide both decomposed to evolve oxygen and oxidized DME at high potentials. Our results lead to two conclusions; (1) coulometry has to be coupled with quantitative gas consumption and evolution data to properly characterize the rechargeability of Li-air batteries, and (2) chemical and electrochemical electrolyte stability in the presence of lithium peroxide and its intermediates is essential to produce a truly reversible Li-O2 electrochemistry.

  7. Molecular dynamics study of self-agglomeration of charged fullerenes in solvents.

    Science.gov (United States)

    Banerjee, Soumik

    2013-01-28

    The agglomeration of fullerenes in solvents is an important phenomenon that is relevant to controlled synthesis of fullerene-based nanowires as well as fullerene-based composites. The molecular aggregation in solvents depends on the atomistic interactions of fullerene with the solvent and is made complicated by the fact that fullerenes accrue negative surface charges when present in solvents such as water. In the present work, we simulated fullerenes of varying size and shape (C60, C180, C240, and C540) with and without surface charges in polar protic (water), polar aprotic (acetone), and nonpolar (toluene) solvents using molecular dynamics method. Our results demonstrate that uncharged fullerenes form agglomerates in polar solvents such as water and acetone and remain relatively dispersed in nonpolar toluene. The presence of surface charge significantly reduces agglomerate size in water and acetone. Additionally, the relative influence of surface charge on fullerene agglomeration depends on the size and geometry of the fullerene with larger fullerenes forming relatively smaller agglomerates. We evaluated the diffusion coefficients of solvent molecules within the solvation shell of fullerenes and observed that they are much lower than the bulk solvent and are strongly associated with the fullerenes as seen in the corresponding radial distribution functions. To correlate agglomerate size with the binding energy between fullerenes, we evaluated the potential of mean force between fullerenes in each solvent. Consistent with the solubility of fullerenes, binding energy between fullerenes is the greatest in water followed by acetone and toluene. The presence of charge decreases the binding energy of fullerenes in water and thus results in dispersed fullerenes.

  8. Lipase catalyzed esterification of glycidol in nonaqueous solvents: solvent effects on enzymatic activity.

    Science.gov (United States)

    Martins, J F; de Sampaio, T C; de Carvalho, I B; Barreiros, S

    1994-06-05

    We studied the effect of organic solvents on the kinetics of porcine pancreatic lipase (pp) for the resolution of racemic glycidol through esterification with butyric acid. We quantified ppl hydration by measuring water sorption isotherms for the enzyme in the solvents/mixtures tested. The determination of initial rates as a function of enzyme hydration revealed that the enzyme exhibits maximum apparent activity in the solvents/mixtures at the same water content (9% to 11% w/w) within the associated experimental error. The maximum initial rates are different in all the media and correlate well with the logarithm of the molar solubility of water in the media, higher initial rates being observed in the solvents/mixtures with lower water solubilities. The data for the mixtures indicate that ppl apparent activity responds to bulk property of the solvent. Measurements of enzyme particle sizes in five of the solvents, as function of enzyme hydration, revealed that mean particle sizes increased with enzyme hydration in all the solvents, differences between solvents being more pronounced at enzyme hydration levels close to 10%. At this hydration level, solvents having a higher water content lead to lower reaction rates; these are the solvents where the mean enzyme particle sizes are greater. Calculation of the observable modulus indicates there are no internal diffusion limitations. The observed correlation between changes in initial rates and changes in external surface area of the enzyme particles suggests that interfacial activation of ppl is only effective at the external surface of the particles. Data obtained for the mixtures indicate that ppl enantioselectivity depends on specific solvent-enzyme interactions. We make reference to ppl hydration and activity in supercritical carbon dioxide.

  9. Ultrasensitive 4-methylumbelliferone fluorimetric determination of water contents in aprotic solvents.

    Science.gov (United States)

    Kłucińska, Katarzyna; Jurczakowski, Rafał; Maksymiuk, Krzysztof; Michalska, Agata

    2015-01-01

    A novel approach to the quantification of relatively small amounts of water present in low polarity, aprotic solvents is proposed. This method takes advantage of protolitic reaction of 4-methylumbelliferone dissolved in the solvent with water, acting as a base. The low emission intensity neutral 4-methylumbelliferone is transformed in reaction with water to a highly fluorescent anionic form. Thus the increase in emission intensity is observed for increasing water contents in aprotic solvents. For low water contents and highly lipophilic solvents, this method yields (in practical conditions) higher sensitivity compared to biamperometric Karl Fischer titration method in volumetric mode. It is also shown that organic compounds of protolitic character (amines, acids) not only interfere with water contents determination but increase the sensitivity of emission vs. water contents dependence. Introduction of aqueous solution of strong acid or base (HCl or NaOH) has similar effect on the system as introduction of pure water.

  10. Solvent Hold Tank Sample Results for MCU-15-556-557-558. March 2015 Monthly Sample

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-05-04

    Savannah River National Laboratory (SRNL) received one set of Solvent Hold Tank (SHT) samples (MCU-15-556, MCU-15-557, and MCU-15-558), pulled on 03/16/2015 for analysis. The samples were combined and analyzed for composition. Analysis of the composite sample MCU-15-556-557-558 indicated a low concentration (~ 78 % of nominal) of the suppressor (TiDG) and concentrations of the extractant (MaxCalix), and of the modifier (CS-7SB) in the solvent that were slightly lower than nominal. This analysis confirms the addition of TiDG, MaxCalix, and modifier to the solvent in February 2015. Based on the current monthly sample, the levels of TiDG, MaxCalix, and modifier are sufficient for continuing operation without adding a trim at this time. No impurities above the 1000 ppm level were found in this solvent by the Semi-Volatile Organic Analysis (SVOA). However, the p-nut vials that delivered the samples contained small (1 mm) droplets of oxidized modifier and amides (as detected by the FTIR analysis). In addition, up to 21 microgram of mercury per gram of solvent (or 17.4 µg/mL) was detected in this sample. The laboratory will continue to monitor the quality of the solvent in particular for any new impurities or degradation of the solvent components.

  11. Anion-π aromatic neutral tweezers complexes: are they stable in polar solvents?

    Science.gov (United States)

    Sánchez-Lozano, Marta; Otero, Nicolás; Hermida-Ramón, Jose M; Estévez, Carlos M; Mandado, Marcos

    2011-03-17

    The impact of the solvent environment on the stabilization of the complexes formed by fluorine (T-F) and cyanide (T-CN) substituted tweezers with halide anions has been investigated theoretically. The study was carried out using computational methodologies based on density functional theory (DFT) and symmetry adapted perturbation theory (SAPT). Interaction energies were obtained at the M05-2X/6-31+G* level. The obtained results show a large stability of the complexes in solvents with large dielectric constant and prove the suitability of these molecular tweezers as potential hosts for anion recognition in solution. A detailed analysis of the effects of the solvent on the electron withdrawing ability of the substituents and its influence on the complex stability has been performed. In particular, the interaction energy in solution was split up into intermonomer and solvent-complex terms. In turn, the intermonomer interaction energy was partitioned into electrostatic, exchange, and polarization terms. Polar resonance structures in T-CN complexes are favored by polar solvents, giving rise to a stabilization of the intermonomer interaction, the opposite is found for T-F complexes. The solvent-complex energy increases with the polarity of the solvent in T-CN complexes, nonetheless the energy reaches a maximum and then decreases slowly in T-F complexes. An electron density analysis was also performed before and after complexation, providing an explanation to the trends followed by the interaction energies and their different components in solution.

  12. Properties of polylactide inks for solvent-cast printing of three-dimensional freeform microstructures.

    Science.gov (United States)

    Guo, Shuang-Zhuang; Heuzey, Marie-Claude; Therriault, Daniel

    2014-02-01

    Solvent-cast printing is a highly versatile microfabrication technique that can be used to construct various geometries such as filaments, towers, scaffolds, and freeform circular spirals by the robotic deposition of a polymer solution ink onto a moving stage. In this work, we have performed a comprehensive characterization of the solvent-cast printing process using polylactide (PLA) solutions by analyzing the flow behavior of the solutions, the solvent evaporation kinetics, and the effect of process-related parameters on the crystallization of the extruded filaments. Rotational rheometry at low to moderate shear rates showed a nearly Newtonian behavior of the PLA solutions, while capillary flow analysis based on process-related data indicated shear thinning at high shear rates. Solvent vaporization tests suggested that the internal diffusion of the solvent through the filaments controlled the solvent removal of the extrudates. Different kinds of three-dimensional (3D) structures including a layer-by-layer tower, nine-layer scaffold, and freeform spiral were fabricated, and a processing map was given to show the proper ranges of process-related parameters (i.e., polymer content, applied pressure, nozzle diameter, and robot velocity) for the different geometries. The results of differential scanning calorimetry revealed that slow solvent evaporation could increase the ability of PLA to complete its crystallization process during the filament drying stage. The method developed here offers a new perspective for manufacturing complex structures from polymer solutions and provides guidelines to optimize the various parameters for 3D geometry fabrication.

  13. Solvent Hold Tank Sample Results For MCU-15-750-751-752-: June Monthly Sample

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-07

    Savannah River National Laboratory (SRNL) received one set of Solvent Hold Tank (SHT) samples (MCU-15-750, MCU-15-751, and MCU-15-752), pulled on 06/22/2015 for analysis. The samples were combined and analyzed for composition. Analysis of the composite sample MCU-15-750-751-752 indicated a low concentration (~ 49 % of nominal) of the suppressor (TiDG) and slightly lower than nominal concentrations of the extractant (MaxCalix), and of the modifier (Cs-7SB) in the solvent. This analysis confirms the addition of TiDG, MaxCalix, and modifier to the solvent in February 2015. Based on the current monthly sample, the levels of TiDG, MaxCalix, and modifier are sufficient for continuing operation without adding a trim at this time but it is recommended that an addition of TiDG, modifier and Isopar™L should be made in the near future. No impurities above the 1000 ppm level were found in this solvent by the Semi-Volatile Organic Analysis (SVOA). No impurities were observed in the Hydrogen Nuclear Magnetic Resonance (HNMR). In addition, up to 13.9 micrograms of mercury per gram of solvent (or 11.5 µg/mL) was detected in this sample. The laboratory will continue to monitor the quality of the solvent in particular for any new impurities or degradation of the solvent components.

  14. European solvent industry group generic exposure scenario risk and exposure tool

    OpenAIRE

    Zaleski, Rosemary T.; Qian, Hua; Zelenka, Michael P; George-Ares, Anita; Money, Chris

    2013-01-01

    The European Solvents Industry Group (ESIG) Generic Exposure Scenario (GES) Risk and Exposure Tool (EGRET) was developed to facilitate the safety evaluation of consumer uses of solvents, as required by the European Union Registration, Evaluation and Authorization of Chemicals (REACH) Regulation. This exposure-based risk assessment tool provides estimates of both exposure and risk characterization ratios for consumer uses. It builds upon the consumer portion of the European Center for Ecotoxic...

  15. Solvent System Selection Strategies in Countercurrent Separation

    Science.gov (United States)

    Liu, Yang; Friesen, J. Brent; McAlpine, James B.; Pauli, Guido F.

    2015-01-01

    The majority of applications in countercurrent and centrifugal partition chromatography, collectively known as countercurrent separation, are dedicated to medicinal plant and natural product research. In countercurrent separation, the selection of the appropriate solvent system is of utmost importance as it is the equivalent to the simultaneous choice of column and eluent in liquid chromatography. However, solvent system selection is often laborious, involving extensive partition and/or analytical trials. Therefore, simplified solvent system selection strategies that predict the partition coefficients and, thus, analyte behavior are in high demand and may advance both the science of countercurrent separation and its applications. The last decade of solvent system selection theory and applications are critically reviewed, and strategies are classified according to their data input requirements. This offers the practitioner an up-to-date overview of rationales and methods for choosing an efficient solvent system, provides a perspective regarding their accuracy, reliability, and practicality, and discusses the possibility of combining multiple methods for enhanced prediction power. PMID:26393937

  16. Chlorinated solvent replacements recycle/recovery review report

    Energy Technology Data Exchange (ETDEWEB)

    Beal, M.; Hsu, D.; McAtee, R.E.; Weidner, J.R. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Berg, L.; McCandless, F.P.; Waltari, S.; Peterson, C. (Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering)

    1992-08-01

    This report is a literature review of waste solvents recycle/recovery methods and shows the results of solvent separations using membrane and distillation technologies. The experimental solvent recovery methods were conducted on solvent replacements for chlorinated solvents at Montana State University. The literature review covers waste solvents separation using distillation, membranes decantation, filtration, carbon adsorption, solvent extraction, and other vapor-phase separation techniques. The results of this study identify solvent distillation methods as the most common separation technique. The alternative separation methods typically supplement distillation. The study shows the need for industries to identify waste solvent disposal methods and investigate the economics of waste solvent recycling as a possible waste reduction method.

  17. Modeling of Entangled Network Chains and Linear Solvent Chains in a Single-Chain-Mean-Field Slip-Link Model

    Science.gov (United States)

    2013-09-01

    J. L. Influence of Solvent Size on the Mechanical Properties and Rheology of Polydimethylsiloxane-based Polymeric Gels . Polymer 2011, 52, 3422–3430...linked polymer networks swollen with polymeric solvent have shown adaptive mechanical response. This frequency dependent response makes these gels ...10 Figure 6. G′ for a PDMS gel containing 50

  18. Recommended methods for purification of solvents and tests for impurities

    CERN Document Server

    Coetzee, J F

    1982-01-01

    Recommended Methods for Purification of Solvents and Tests for Impurities is a compilation of recommended procedures for purification of solvents and tests for solvent impurities. Ten solvents are covered: acetonitrile, sulfolane, propylene carbonate, dimethyl sulfoxide, dimethylformamide, hexamethylphosphoramide, pyridine, ethylenediamine, N-methylacetamide, and N-methylpropionamide. This book is comprised of 12 chapters and opens with an introduction to general aspects of impurity effects. The rationale for the selection of solvent is explained, and the relative reactivities of solutes in di

  19. Rational coformer or solvent selection for pharmaceutical cocrystallization or desolvation.

    Science.gov (United States)

    Abramov, Yuriy A; Loschen, Christoph; Klamt, Andreas

    2012-10-01

    It is demonstrated that the fluid-phase thermodynamics theory conductor-like screening model for real solvents (COSMO-RS) as implemented in the COSMOtherm software can be used for accurate and efficient screening of coformers for active pharmaceutical ingredient (API) cocrystallization. The excess enthalpy, H(ex) , between an API-coformer mixture relative to the pure components reflects the tendency of those two compounds to cocrystallize. Thus, predictive calculations may be performed with decent effort on a large set of molecular data in order to identify potentially new cocrystal systems. In addition, it is demonstrated that COSMO-RS theory allows reasonable ranking of coformers for API solubility improvement. As a result, experiments may be focused on those coformers, which have an increased probability of cocrystallization, leading to the largest improvement of the API solubility. In a similar way as potential coformers are identified for cocrystallization, solvents that do not tend to form solvates may be determined based on the highest H(ex) s with the API. The approach was successfully tested on tyrosine kinase inhibitor axitinib, which has a propensity to form relatively stable solvated structures with the majority of common solvents, as well as on thiophanate-methyl and thiophanate-ethyl benzimidazole fungicides, which form channel solvates.

  20. Effect of solvent extraction on Tunisian esparto wax composition

    Directory of Open Access Journals (Sweden)

    Saâd Inès

    2016-08-01

    Full Text Available The increase of needs for renewable and vegetable based materials will help to drive the market growth of vegetable waxes. Because of their highly variable composition and physicochemical properties, plant waxes have found numerous applications in the: food, cosmetic, candle, coating, polish etc... The aim of this project is to determine the effect of solvent extraction (petroleum ether and ethanol on Tunisian esparto wax composition. The GC-MS was applied in order to determine the waxes compositions. Then, physicochemical parameters of these two samples of waxes: acid value, saponification value, iodine value and melting point were measured in order to deduct their properties and possible fields of uses. Results showed that esparto wax composition depended on the solvent extraction and that major components of the two samples of waxes were: alkanes, esters of fatty acids and phenols. Furthermore, esparto waxes were characterized by an antioxidant and antibacterial activities but the potential of these activities depended on the solvent of wax extraction.

  1. Solvent cleaning of pole transformers containing PCB contaminated insulating oil.

    Science.gov (United States)

    Kanbe, H; Shibuya, M

    2001-01-01

    In 1989, it was discovered that the recycled insulation oil in pole transformers for electric power supply was contaminated with trace amounts of polychlorinated biphenyls (PCBs; maximum 50 mg-PCB/kg-insulation oil). In order to remove the PCBs from transformer components using n-hexane as a solvent, we investigated the relationship between progressive stages of dismantling and cleaning results. The results are summarized as follows: (1) Based on the cleaning test results, we made an estimate of the residual PCB amount on iron and copper components. By dismantling the test pole transformers into the "iron core and coil portion" and cleaning the components, we achieved a residual PCB amount that was below the limit of detection (0.05 mg-PCB/kg-material). To achieve a residual PCB amount below the limit of detection for the transformer paper component, it was necessary to cut the paper into pieces smaller than 5 mm. We were unable to achieve a residual PCB amount below the limit of detection for the wood component. (2) Compared to Japan's stipulated limited concentration standard values for PCBs, the results of the cleaning test show that cleaning iron or copper components with PCBs only on their surface with the solvent n-hexane will satisfy the limited concentration standard values when care is taken to ensure the component surfaces have adequate contact with the cleaning solvent.

  2. Alternative Solvents through Green Chemistry Project

    Science.gov (United States)

    Hintze, Paul E.; Quinn, Jacqueline

    2014-01-01

    Components in the aerospace industry must perform with accuracy and precision under extreme conditions, and surface contamination can be detrimental to the desired performance, especially in cases when the components come into contact with strong oxidizers such as liquid oxygen. Therefore, precision cleaning is an important part of a components preparation prior to utilization in aerospace applications. Current cleaning technologies employ a variety of cleaning agents, many of which are halogenated solvents that are either toxic or cause environmental damage. Thus, this project seeks to identify alternative precision cleaning solvents and technologies, including use of less harmful cleaning solvents, ultrasonic and megasonic agitation, low-pressure plasma cleaning techniques, and supercritical carbon dioxide extraction. Please review all data content found in the Public Data tab located at: https:techport.nasa.govview11697public

  3. Comparison between a Water-Based and a Solvent-Based Impregnation Method towards Dispersed CuO/SBA-15 Catalysts: Texture, Structure and Catalytic Performance in Automotive Exhaust Gas Abatement

    Directory of Open Access Journals (Sweden)

    Qi Xin

    2016-10-01

    Full Text Available Supported copper oxide nanoparticles are a potential candidate for replacing the rare and expensive precious metals within the automotive three-way catalyst. However, a well-designed dispersion method is necessary to allow a stable high loading of active material, compensating its lower intrinsic activity and stability. In this work, a CuO-loaded SBA-15 catalyst has been manufactured by two methods. The ammonia-driven deposition precipitation (ADP and the molecular designed dispersion (MDD methods are both considered as efficient deposition methods to provide well-dispersed copper oxide-based catalysts. Their morphology, copper dispersion and the chemical state of copper were characterized and compared. Due to the differences in the synthesis approach, a difference in the obtained copper oxide phases has been observed, leading to a distinct behavior in the catalytic performance. The structure-activity correlation of both catalysts has also been revealed for automotive exhaust gas abatement. Results demonstrate that various copper species can be formed depending on the precursor–support interaction, affecting selectivity and conversion during the catalytic reaction.

  4. Solvent-resistant microporous polymide membranes

    Science.gov (United States)

    Miller, Warren K.; McCray, Scott B.; Friesen, Dwayne T.

    1998-01-01

    An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

  5. NMR spectroscopy using liquid crystal solvents

    CERN Document Server

    Emsley, JW

    2013-01-01

    NMR Spectroscopy using Liquid Crystal Solvents covers the importance of using a liquid crystal solvent in NMR to derive nuclear dipolar spin-spin coupling constants. This book is composed of ten chapters, and begins with a brief description of the features and benefits of liquid crystal in NMR spectroscopic analysis. The succeeding chapters deal with the mode of operation of nuclear spin Hamiltonian for partially oriented molecules and the analysis of NMR spectra of partially oriented molecules, as well as the determination of rigid molecule structure. These topics are followed by discussions

  6. Occupational exposure to solvents and bladder cancer

    DEFF Research Database (Denmark)

    Hadkhale, Kishor; Martinsen, Jan Ivar; Weiderpass, Elisabete;

    2017-01-01

    logistic regression model was used to estimate hazard ratios (HR) and their 95% confidence intervals (95% CI). Increased risks were observed for trichloroethylene (HR 1.23, 95% 95% CI 1.12-1.40), toluene (HR 1.20, 95% CI 1.00-1.38), benzene (HR 1.16, 95% CI 1.04-1.31), aromatic hydrocarbon solvents (HR 1...... of occupational exposure to trichloroethylene, perchloroethylene, aromatic hydrocarbon solvents, benzene and toluene and the risk of bladder cancer. This article is protected by copyright. All rights reserved....

  7. Summary report for the FY-2015 SACSESS Collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Peterman, Dean Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mincher, Bruce Jay [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    During FY-2015, a collaborative research program was established by the Department of Energy-Nuclear Energy (DOE-NE) Material Recovery and Waste Form Development program and the European Union (EU) Safety of Actinide Separation Processes (SACSESS) program. One component of this collaboration was the evaluation of the radiolytic stability of a Selective ActiNide Extraction (SANEX) separation which utilized a TODGA-based organic solvent and an aqueous phase containing the hydrophilic complexing reagent, SO3-Ph-BTP. To best simulate process conditions, this experiment was irradiated in the radiolysis/hydrolysis test loop located at the Idaho National Laboratory. The effect of irradiation on a SACSESS program iSANEX formulation containing a TODGA-based organic phase and a BTP-based aqueous phase was investigated using irradiations at INL in static and test loop modes. When irradiated in contact with only the acidic aqueous phase, the TODGA organic solution maintained excellent extraction performance of americium, cerium and europium to a maximum absorbed dose of nearly 0.9 MGy. When the aqueous phase was changed to that containing the aqueous soluble BTP, the irradiated aqueous phase showed a dramatic color change, but this does not appear to have adverse effects on solvent extraction performance. Only minor increases in distribution ratios for both the lanthanides and actinide were measured, and the separation factors were essentially unchanged to a maximum absorbed dose of 174 kGy. The determination of the americium, cerium, and europium distribution ratios for the remaining SACSESS test loop samples will be completed in the near future. The analysis of stable metals concentration in the the irradiated aqueous and organic phases will be completed shortly.

  8. Vapor Transport of a Volatile Solvent for a Multicomponent Aerosol Droplet

    CERN Document Server

    Feng, James Q

    2015-01-01

    This work presents analytical formulas derived for evaluating vapor transport of a volatile solvent for an isolated multicomponent droplet in a quiescent environment, based on quasi-steady-state approximation. Among multiple solvent components, only one component is considered to be much more volatile than the rest such that other components are assumed to be nonvolatile remaining unchanged in the droplet during the process of (single-component) volatile solvent evaporation or condensation. For evaporating droplet, the droplet size often initially decreases following the familiar "d^2 law" at an accelerated rate. But toward the end, the rate of droplet size change diminishes due to the presence of nonvolatile cosolvent. Such an acceleration-deceleration reversal behavior is unique for evaporating multicomponent droplet, while the droplet of pure solvent has an accelerated rate of size change all the way through the end. This reversal behavior is also reflected in the droplet surface temperature evolution as "...

  9. Poly-(3-hexylthiophene) Aggregate Formation in Binary Solvent Mixtures: An Excitonic Coupling Analysis

    Science.gov (United States)

    Boucher, David; Johnson, Calynn

    2014-03-01

    We have studied the aggregation behavior of P3HT [Mn ~ 28.2 kDa, regioregularity >96 %, PDI ~ 1.3] in 96 solvent mixtures is studied using UV-Vis absorption spectroscopy. We used Hansen solubility parameters (HSPs) and Spano excitonic coupling analyses to identify correlations between the properties of the solvent mixtures and the extent of structural order of the aggregates. It is clear that the identity of the poor solvent used to drive aggregation has a significant impact on the excitonic coupling behavior and, hence, the structural order of the P3HT aggregates. However, solubility parameter theory does not account nor provide a predictive theory for the observed trends. Instead, qualitative arguments based on the nature of the interactions between the solvents and the polythiophene and hexyl side chain motifs are used to rationalize the kinetics of formation and the observed excitonic coupling characteristics of the P3HT aggregates.

  10. Natural deep eutectic solvents providing enhanced stability of natural colorants from safflower (Carthamus tinctorius).

    Science.gov (United States)

    Dai, Yuntao; Verpoorte, Robert; Choi, Young Hae

    2014-09-15

    A certain combination of natural products in the solid state becomes liquid, so called natural deep eutectic solvents (NADES). Recently, they have been considered promising new green solvents for foods, cosmetics and pharmaceuticals due to their unique solvent power which can dissolve many non-water-soluble compounds and their low toxicity. However, in addition to the features as solvents, the stabilisation ability of NADES for compounds is important for their further applications. In the study, the stability analysis demonstrates that natural pigments from safflower are more stable in sugar-based NADES than in water or 40% ethanol solution. Notably, the stabilisation capacity of NADES can be adjusted by reducing water content with increasing viscosity. The strong stabilisation ability is due to the formation of strong hydrogen bonding interactions between solutes and NADES molecules. The stabilising ability of NADES for phenolic compounds shows great promise for their applications in food, cosmetic and pharmaceutical industries.

  11. How to design a good photoresist solvent package using solubility parameters and high-throughput research

    Science.gov (United States)

    Tate, Michael P.; Cutler, Charlotte; Sakillaris, Mike; Kaufman, Michael; Estelle, Thomas; Mohler, Carol; Tucker, Chris; Thackeray, Jim

    2014-03-01

    Understanding fundamental properties of photoresists and how interactions between photoresist components affect performance targets are crucial to the continued success of photoresists. More specifically, polymer solubility is critical to the overall performance capability of the photoresist formulation. While several theories describe polymer solvent solubility, the most common industrially applied method is Hansen's solubility parameters. Hansen's method, based on regular solution theory, describes a solute's ability to dissolve in a solvent or solvent blend using four physical properties determined experimentally through regression of solubility data in many known solvents. The four physical parameters are dispersion, polarity, hydrogen bonding, and radius of interaction. Using these parameters a relative cohesive energy difference (RED), which describes a polymer's likelihood to dissolve in a given solvent blend, may be calculated. Leveraging a high throughput workflow to prepare and analyze the thousands of samples necessary to calculate the Hansen's solubility parameters from many different methacrylate-based polymers, we compare the physical descriptors to reveal a large range of polarities and hydrogen bonding. Further, we find that Hansen's model correctly predicts the soluble/insoluble state of 3-component solvent blends where the dispersion, polar, hydrogen-bonding, and radius of interaction values were determined through regression of experimental values. These modeling capabilities have allowed for optimization of the photoresist solubility from initial blending through application providing valuable insights into the nature of photoresist.

  12. Experimental approach versus COSMO-RS assisted solvent screening for predicting the solubility of rapeseed oil

    Directory of Open Access Journals (Sweden)

    Sicaire Anne-Gaëlle

    2015-07-01

    Full Text Available Vegetable oils take a large part in industry for food and non-food applications. However the extraction process of oil from oilseeds includes a solvent extraction step using hexane. Despite its various advantages it presents numerous drawbacks; it is sourced from petroleum, it has a high flammability and it appears to be dangerous for health and environment (CMR2. This study presents a theoretical screening using COSMO-RS simulations of the relative solubility of vegetable oil constituents regarding several bio-based solvents as well as an experimental screening of the efficiency of these solvents. The aim is to correlate simulations and experiments and give a preliminary evaluation for the substitution of hexane by bio-based solvents for the extraction of vegetable oils. Differences between theory and practice have been noticed for several solvents such as terpenes that appeared to be good candidates in theory and that were in fact the solvents that gave the lowest extraction yield.

  13. Solvent tuned single molecule dual emission in protic solvents: effect of polarity and H-bonding.

    Science.gov (United States)

    Chevreux, S; Allain, C; Wilbraham, L; Nakatani, K; Jacques, P; Ciofini, I; Lemercier, G

    2015-01-01

    Phen-PENMe2 has recently been proposed as a promising new molecule displaying solvent-tuned dual emission, highlighting an original and newly-described charge transfer model. The study of the photophysical behaviour of this molecule was extended to include protic solvents. The effects of polarity and hydrogen bonding lead to an even more evident dual emission associated with a large multi-emission band in some solvents like methanol, highlighting Phen-PENMe2 as a promising candidate for white light emission.

  14. Controlling Actinide Hydration in Mixed Solvent Systems: Towards Tunable Solvent Systems to Close the Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Sue B. [Washington State Univ., Pullman, WA (United States). Dept. of Chemistry

    2016-10-31

    The goal of this project has been to define the extent of hydration the f-elements and other cations in mixed solvent electrolyte systems. Methanol-water and other mixed solvent systems have been studied, where the solvent dielectric constant was varied systematically. Thermodynamic and spectroscopic studies provide details concerning the energetics of complexation and other reactions of these cations. This information has also been used to advance new understanding of the behavior of these cations in a variety of systems, ranging from environmental studies, chromatographic approaches, and ionization processes for mass spectrometry.

  15. Used Solvent Testing and Reclamation. Volume 2. Vapor Degreasing and Precision Cleaning Solvents

    Science.gov (United States)

    1988-12-01

    Dependence of the 1,3-Dioxolane/AlCI 3 Reaction Using Arrhenius’ Law 88 36 Effect of 1,4-Dioxane on Reactor Pressure 91 67 Effect of 1,4-Dioxane on HCI...and spent solvent. This process was performed for all of the three solvents. Inhibitor Kinetic Studies Batch Reactions. Batch reactor kinetic studies...acceptor in chlorinated solvents. It is an 4 80. Levenspiel , Chemical Reaction Engineering, 2nd ed. (John Wiley and Sons, 1972), pp 41-86. 490

  16. Mixed Solvent Reactive Recrystallization of Sodium Carbonate

    NARCIS (Netherlands)

    Gaertner, R.S.

    2005-01-01

    Investigation of the reactive recrystallization of trona (sodium sesquicarbonate) and sodium bicarbonate to sodium carbonate (soda) in a mixed solvent led to the design of several alternative, less energy consumptive, economically very attractive process routes for the production of soda from all pr

  17. Solvent-Free Synthesis of Chalcones

    Science.gov (United States)

    Palleros, Daniel R.

    2004-01-01

    The synthesis of twenty different chalcones in the absence of solvent is presented. The results indicated that out of the twenty different chalcones investigated seventeen can be obtained in a matter of minutes by mixing the corresponding benzaldehyde and acetophenone in the presence of solid NaOH in a mortar with pestle.

  18. Computer-Aided Solvent Screening for Biocatalysis

    DEFF Research Database (Denmark)

    Abildskov, Jens; Leeuwen, M.B. van; Boeriu, C.G.;

    2013-01-01

    . Esterification of acrylic acid with octanol is also addressed. Solvents are screened and candidates identified, confirming existing experimental results. Although the examples involve lipases, the method is quite general, so there seems to be no preclusion against application to other biocatalysts....

  19. Organic solvent nanofiltration: prospects and application

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, A V; Korneeva, G A; Tereshchenko, Gennadii F [A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow (Russian Federation)

    2008-11-30

    The key lines of research in a new field of the membrane science and technology, viz., organic solvent nanofiltration, are considered. The prospects for its use in chemical, petrochemical and food industries are discussed. Attention is focused on membranes developed for this method.

  20. Selective solvent absorption in coal conversion

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, J.W.; Lapucha, A.; Lazarov, L.; Amui, J.

    1992-04-01

    The objectives of this project are: (1) to determine the importance of the presence of added hydrogen donor compounds within the coal in the first stage of direct liquefaction processes; and (2) to determine the composition of the solvent absorbed by and present within the coal in the first stage of direct coal liquefaction.

  1. Association between maternal occupational exposure to organic solvents and congenital heart defects, National Birth Defects Prevention Study, 1997–2002

    Science.gov (United States)

    Gilboa, SM; Desrosiers, TA; Lawson, CC; Lupo, PJ; Riehle-Colarusso, T; Stewart, PA; van Wijngaarden, E; Waters, MA; Correa, A

    2015-01-01

    Objective To examine the relation between congenital heart defects (CHDs) in offspring and estimated maternal occupational exposure to chlorinated solvents, aromatic solvents, and Stoddard solvent during the period from one month before conception through the first trimester. Methods The study population included mothers of infants with simple, isolated CHDs and mothers of control infants who delivered from 1997 through 2002 and participated in the National Birth Defects Prevention Study. Two methods to assess occupational solvent exposure were employed: an expert consensus-based approach and a literature-based approach. Multiple logistic regression was used to calculate adjusted odds ratios (OR) and 95% confidence intervals (CI) for the association between solvent classes and CHDs. Results 2,951 control mothers and 2,047 CHD case mothers were included. Using the consensus-based approach, associations were observed for exposure to any solvent and any chlorinated solvent with perimembranous ventricular septal defects (OR 1.6; 95% CI 1.0 to 2.6 and OR 1.7; 95% CI 1.0 to 2.8 respectively). Using the literature-based approach, associations were observed for: any solvent exposure with aortic stenosis (OR 2.1; 95% CI 1.1 to 4.1); and Stoddard solvent exposure with d-transposition of the great arteries (OR 2.0; 95% CI 1.0 to 4.2), right ventricular outflow tract obstruction defects (OR 1.9; 95% CI 1.1 to 3.3), and pulmonary valve stenosis (OR 2.1; 95% CI 1.1 to 3.8). Conclusions We found evidence of associations between occupational exposure to solvents and several types of CHDs. These results should be interpreted in light of the potential for misclassification of exposure. PMID:22811060

  2. Predicting the activity coefficients of free-solvent for concentrated globular protein solutions using independently determined physical parameters.

    Directory of Open Access Journals (Sweden)

    Devin W McBride

    Full Text Available The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent model, which has previously been shown to provide excellent prediction of the osmotic pressure of concentrated and crowded globular proteins in aqueous solutions up to near-saturation concentrations. Thus, this model uses only the independently determined, physically realizable quantities: mole fraction, solvent accessible surface area, and ion binding, in its prediction. Predictions are presented for the activity coefficients of free-solvent for near-saturated protein solutions containing either bovine serum albumin or hemoglobin. As a verification step, the predictability of the model for the activity coefficient of sucrose solutions was evaluated. The predicted activity coefficients of free-solvent are compared to the calculated activity coefficients of free-solvent based on osmotic pressure data. It is observed that the predicted activity coefficients are increasingly dependent on the solute-solvent parameters as the protein concentration increases to near-saturation concentrations.

  3. Predicting the activity coefficients of free-solvent for concentrated globular protein solutions using independently determined physical parameters.

    Science.gov (United States)

    McBride, Devin W; Rodgers, Victor G J

    2013-01-01

    The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent model, which has previously been shown to provide excellent prediction of the osmotic pressure of concentrated and crowded globular proteins in aqueous solutions up to near-saturation concentrations. Thus, this model uses only the independently determined, physically realizable quantities: mole fraction, solvent accessible surface area, and ion binding, in its prediction. Predictions are presented for the activity coefficients of free-solvent for near-saturated protein solutions containing either bovine serum albumin or hemoglobin. As a verification step, the predictability of the model for the activity coefficient of sucrose solutions was evaluated. The predicted activity coefficients of free-solvent are compared to the calculated activity coefficients of free-solvent based on osmotic pressure data. It is observed that the predicted activity coefficients are increasingly dependent on the solute-solvent parameters as the protein concentration increases to near-saturation concentrations.

  4. Fabrication of Janus particles composed of poly (lactic-co-glycolic) acid and hard fat using a solvent evaporation method.

    Science.gov (United States)

    Matsumoto, Akihiro; Murao, Satoshi; Matsumoto, Michiko; Watanabe, Chie; Murakami, Masahiro

    2016-01-01

    The feasibility of fabricating Janus particles based on phase separation between a hard fat and a biocompatible polymer was investigated. The solvent evaporation method used involved preparing an oil-in-water (o/w) emulsion with a mixture of poly (lactic-co-glycolic) acid (PLGA), hard fat, and an organic solvent as the oil phase and a polyvinyl alcohol aqueous solution as the water phase. The Janus particles were formed when the solvent was evaporated to obtain certain concentrations of PLGA and hard fat in the oil phase, at which phase separation was estimated to occur based on the phase diagram analysis. The hard fat hemisphere was proven to be the oil phase using a lipophilic dye Oil Red O. When the solvent evaporation process was performed maintaining a specific volume during the emulsification process; Janus particles were formed within 1.5 h. However, the formed Janus particles were destroyed by stirring for over 6 h. In contrast, a few Janus particles were formed when enough water to dissolve the oil phase solvent was added to the emulsion immediately after the emulsification process. The optimized volume of the solvent evaporation medium dominantly formed Janus particles and maintained the conformation for over 6 h with stirring. These results indicate that the formation and stability of Janus particles depend on the rate of solvent evaporation. Therefore, optimization of the solvent evaporation rate is critical to obtaining stable PLGA and hard fat Janus particles.

  5. A calorimetric study of energy conversion efficiency of a sonochemical reactor at 500 kHz for organic solvents.

    Science.gov (United States)

    Toma, Maricela; Fukutomi, Satoshi; Asakura, Yoshiyuki; Koda, Shinobu

    2011-01-01

    It would seem that the economic viability is yet to be established for a great number of sonochemical processes, owning to their perfectible ultrasonic equipments. Industrial scale sonoreactors may become more important as a result of mastering the parameters with influence on their energy balance. This work related the solvent type to the energy efficiency as the first step of a complex study aiming to assess the energy balance of sonochemical reactors at 500 kHz. Quantitative measurements of ultrasonic power for water and 10 pure organic solvents were performed by calorimetry for a cylindrically shaped sonochemical reactor with a bottom mounted vibrating plate. It was found that the ultrasonic power is strongly related to the solvent, the energy conversion for organic liquids is half from that of water and there is a drop in energy efficiency for filling levels up to 250 mm organic solvents. Surface tension, viscosity and vapor pressure influence the energy conversion for organic solvents, but it is difficult explain these findings based on physical properties of solvents alone. The apparent intensity of the atomization process shows a good agreement with the experimentally determined values for energy conversion for water and the solvent group studied here. This study revealed that to attain the same ultrasonic power level, more electrical energy is need for organic solvents as compared to water. The energy balance equation has been defined based on these findings by considering an energy term for atomization.

  6. Solvent density mode instability in non-polar solutions

    Indian Academy of Sciences (India)

    Susmita Kar; Ranjit Biswas; J Chakrabarti

    2008-08-01

    We analyse the origin of the multiple long time scales associated with the long time decay observed in non-polar solvation dynamics by linear stability analysis of solvent density modes where the effects of compressibility and solvent structure are systematically incorporated. The coupling of the solute–solvent interactions at both ground and excited states of the solute with the compressibility and solvent structure is found to have important effects on the time scales. The present theory suggests that the relatively longer time constant is controlled by the solvent compressibility, while the solvent structure at the nearest-neighbour length scale dominates the shorter time constant.

  7. 3D-printed paper spray ionization cartridge with fast wetting and continuous solvent supply features.

    Science.gov (United States)

    Salentijn, Gert I J; Permentier, Hjalmar P; Verpoorte, Elisabeth

    2014-12-02

    We report the development of a 3D-printed cartridge for paper spray ionization (PSI) that can be used almost immediately after solvent introduction in a dedicated reservoir and allows prolonged spray generation from a paper tip. The fast wetting feature described in this work is based on capillary action through paper and movement of fluid between paper and the cartridge material (polylactic acid, PLA). The influence of solvent composition, PLA conditioning of the cartridge with isopropanol, and solvent volume introduced into the reservoir have been investigated with relation to wetting time and the amount of solvent consumed for wetting. Spray has been demonstrated with this cartridge for tens of minutes, without any external pumping. It is shown that fast wetting and spray generation can easily be achieved using a number of solvent mixtures commonly used for PSI. The PSI cartridge was applied to the analysis of lidocaine from a paper tip using different solvent mixtures, and to the analysis of lidocaine from a serum sample. Finally, a demonstration of online paper chromatography-mass spectrometry is given.

  8. Crosslinked copolyazoles with a zwitterionic structure for organic solvent resistant membranes

    KAUST Repository

    Chisca, Stefan

    2015-01-01

    The preparation of crosslinked membranes with a zwitterionic structure based on a facile reaction between a newly synthesized copolyazole with free OH groups and (3-glycidyloxypropyl)trimethoxysilane (GPTMS) is reported. The new OH-functionalized copolyazole is soluble in common organic solvents, such as tetrahydrofuran (THF), dimethylsulfoxide (DMSO), N,N′-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP) and can be easily processed by phase inversion. After crosslinking with GPTMS, the membranes acquire high solvent resistance. We show the membrane performance and the influence of the crosslinking reaction conditions on the thermal stability, surface polarity, pore morphology, and solvent resistance. By using UV-spectroscopy we monitored the solvent resistance of the membranes in four aggressive solvents (THF, DMSO, DMF and NMP) for 30 days. After this time, only minor changes (less than 2%) were detected for membranes subjected to a crosslinking reaction for 6 hours or longer. Our data suggest that the novel crosslinked membranes can be used for industrial applications in wide harsh environments in the presence of organic solvents.

  9. Molecular dynamics simulations of organohalide perovskite precursors: solvent effects in the formation of perovskite solar cells.

    Science.gov (United States)

    Gutierrez-Sevillano, Juan José; Ahmad, Shahzada; Calero, Sofía; Anta, Juan A

    2015-09-21

    The stability and desirable crystal formation of organohalide perovskite semiconductors is of utmost relevance to ensure the success of perovskites in photovoltaic technology. Herein we have simulated the dynamics of ionic precursors toward the formation of embryonic organohalide perovskite CH3NH3PbI3 units in the presence of solvent molecules using Molecular Dynamics. The calculations involved, a variable amount of Pb(2+), I(-), and CH3NH3(+) ionic precursors in water, pentane and a mixture of these two solvents. Suitable force fields for solvents and precursors have been tested and used to carry out the simulations. Radial distribution functions and mean square displacements confirm the formation of basic perovskite crystalline units in pure pentane - taken as a simple and archetypal organic solvent. In contrast, simulations in water confirm the stability of the solvated ionic precursors, which prevents their aggregation to form the perovskite compound. We have found that in the case of a water/pentane binary solvent, a relatively small amount of water did not hinder the perovskite formation. Thus, our findings suggest that the cause of the poor stability of perovskite films in the presence of moisture is a chemical reaction, rather than the polar nature of the solvents. Based on the results, a set of force-field parameters to study from first principles perovskite formation and stability, also in the solid phase, is proposed.

  10. Absorption and Emission Sensitivity of 2-(2'-Hydroxyphenyl)benzoxazole to Solvents and Impurities.

    Science.gov (United States)

    Yuan, Zhao; Tang, Qing; Sreenath, Kesavapillai; Simmons, J Tyler; Younes, Ali H; Jiang, De-En; Zhu, Lei

    2015-01-01

    2-(2'-Hydroxyphenyl)benzoxazole (HBO) is known for undergoing intramolecular proton transfer in the excited state to result in the emission of its tautomer. A minor long-wavelength absorption band in the range 370-420 nm has been reported in highly polar solvents such as dimethylsulfoxide (DMSO). However, the nature of this species has not been entirely clarified. In this work, we provide evidence that this long-wavelength absorption band might have been caused by base or metal salt impurities that are introduced into the spectral sample during solvent transport using glass Pasteur pipettes. The contamination by base or metal salt could be avoided by using borosilicate glass syringes or nonglass pipettes in sample handling. Quantum chemical calculations conclude that solvent-mediated deprotonation is too energetically costly to occur without the aid of a base of an adequate strength. In the presence of such a base, the deprotonation of HBO and its effect on emission are investigated in dichloromethane and DMSO, the latter of which facilitates deprotonation much more readily than the former. Finally, the absorption and emission spectra of HBO in 13 solvents are reported, from which it is concluded that ESIPT is hindered in polar solvents that are also strong hydrogen bond acceptors.

  11. Solvent hold tank sample results for MCU-16-53-55. January 2016 Monthly sample

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F. F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jones, D. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-28

    Savannah River National Laboratory (SRNL) received one set of Solvent Hold Tank (SHT) samples (MCU-16-53-54-55), pulled on 01/25/2016 for analysis. The samples were combined and analyzed for composition. Analysis of the composite sample MCU-16-53-54-55 indicated the Isopar™L, and MaxCalix are at nominal levels. The modifier and TiDG concentrations are 3% and 23 % below their nominal concentrations. This analysis confirms the addition of TiDG, MaxCalix, and modifier to the solvent on November 28, 2015. Based on the current monthly sample, the levels of TiDG, Isopar™L, MaxCalix, and modifier are sufficient for continuing operation but are expected to decrease with time. Periodic characterization and trimming additions to the solvent are recommended. No impurities above the 1000 ppm level were found in this solvent by the Semi-Volatile Organic Analysis (SVOA). No impurities were observed in the Hydrogen Nuclear Magnetic Resonance (HNMR). However, the Fourier transform infra-red spectroscopy (FTIR) method detected trace levels (a few ppm) of amides (a possible degradation product of TiDG). In addition, up to 21 ± 4 micrograms of mercury per gram of solvent (or 17.5 μg/mL) was detected in this sample. There appears to be a possible correlation between the mercury level and the TiDG concentration in the solvent. The current gamma level (9.16 E4 dpm/mL) confirmed that the gamma concentration has returned to previous level where the process operated normally and as expected. The laboratory will continue to monitor the quality of the solvent in particular for any new impurities or degradation of the solvent components.

  12. Enhanced catalysis by solvent improvement. Quarterly technical progress report, 1 April-30 June 1983

    Energy Technology Data Exchange (ETDEWEB)

    Garg, D.; Miller, R.N.; Givens, E.N.; Tarrer, A.R.; Guin, J.A.; Curtis, C.W.

    1983-11-01

    This report describes the results from liquefaction solvent modification, coal liquefaction with original and modified solvents, catalyst selection, coal pretreatment, and pretreatment followed by liquefaction experiments. The effect of liquefaction reaction conditions on product distribution is also covered in this report. Significant removal of nitrogen compounds from coal-derived liquefaction solvent was obtained by treating it with anhydrous hydrochloric acid or silica gel. The removal of nitrogen compounds with HCl or silica gel was also accompanied by 25 to 40% removal of oxygen compounds. Treating liquefaction solvent with aqueous NaOH or zeolite removed significant amounts of phenolic compounds. Oxygen removal was also accompanied by a partial removal of nitrogen compounds. Sequential treatment of coal-derived liquefaction solvent with HCl followed by silica gel or NaOH followed by HCl resulted in complete removal of nitrogen compounds. Liquefying coals in the presence of coal-derived liquefaction solvents modified by the removal of nitrogen or oxygen compounds or both significantly increased the oil yield in the absence of catalyst. The overall coal conversion, however, decreased only slightly with these treated solvents. A significant increase in the oil yield was also noted during catalytic liquefaction with the pretreated solvents. The overall coal conversion also increased during catalytic liquefaction of coal. At a concentration level of 250 ppM metal based on coal molybdenum catalyst was more active than nickel. At this level the activity of molybdenum was also higher than that noted with 1 wt% iron or zinc. Combination of metals such as iron and molybdenum or zinc and molybdenum yielded significantly higher oil yield compared to individual metals alone. 1 ref., 2 figs., 28 tabs.

  13. Solvent Annealing in Selective Solvents: A Novel Method to Tune the Morphology of Low Band Gap Polymer:Bis-Fullerene Heterojunctions

    Science.gov (United States)

    Dadmun, Mark; Chen, Huipeng; Hsiao, Yu-Che; Hu, Bin

    2014-03-01

    One of the most important challenges facing our society is the development of technologies for renewable energy conversion. Polymeric bulk-heterojunction (BHJ) photovoltaics, based on conjugated polymers and fullerenes, are an economically viable option for low cost renewable power generation. The most promising conjugated polymer:fullerene active layers in organic photovoltaics now utilize low band-gap (LBG) copolymers. Unfortunately, for most of these LBG devices, the as-cast film is not usually optimal, and there are few further treatment available after film deposition to optimize the morphology. To address this problem, we have exploited the selective solubility of the LBG:fullerene nanocomposite components to direct the assembly of these mixtures by annealing in the vapor of a selective solvent. Our recent work demonstrates that annealing in a solvent that is selective to the fullerene forms a sample with fullerene aggregation, while annealing in a solvent vapor that is selective to the polymer forms a thin film with polymer precipitation. There is also a direct correlation between the resultant morphology and OPV performance, increasing PCE by 190%. These results indicate that solvent annealing and solvent choice provides a unique tool to precisely tune the morphology of CP:Fullerene BHJ systems, optimizing the morphology and performance of the active layer.

  14. Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngme [Ewha Womans University, College of Pharmacy (Korea, Republic of); Sah, Eric [University of Notre Dame, College of Science (United States); Sah, Hongkee, E-mail: hsah@ewha.ac.kr [Ewha Womans University, College of Pharmacy (Korea, Republic of)

    2015-11-15

    The objective of this study was to develop a new oil-in-water emulsion-based nanoencapsulation method for the preparation of PLGA nanoparticles using a non-halogenated solvent. PLGA (60–150 mg) was dissolved in 3 ml of methyl propionate, which was vortexed with 4 ml of a 0.5–4 % polyvinyl alcohol solution. This premix was sonicated for 2 min, added into 30 ml of the aqueous polyvinyl alcohol solution, and reacted with 3 ml of 10 N NaOH. Solvent removal was achieved by the alkaline hydrolysis of methyl propionate dissolved in an aqueous phase into water-soluble methanol and sodium propionate. It was a simple but effective technique to quickly harden nanoemulsion droplets into nanoparticles. The appearing PLGA nanoparticles were recovered by ultracentrifugation and/or dialysis, lyophilized with trehalose, and redispersed by water. This nanoencapsulation technique permitted a control of their mean diameters over 151.7 ± 3.8 to 440.2 ± 22.2 nm at mild processing conditions. When the aqueous polyvinyl alcohol concentration was set at ≥1 %, nanoparticles showed uniform distributions with polydispersity indices below 0.1. There were no significant changes in their mean diameters and size distribution patterns before and after lyophilization. When mestranol was encapsulated into nanoparticles, the drug was completely nanoencapsulated: depending on experimental conditions, their encapsulation efficiencies were determined to be 99.4 ± 7.2 to 105.8 ± 6.3 %. This simple, facile nanoencapsulation technique might have versatile applications for the preparation of polymeric nanoparticulate dosage forms.Graphical AbstractSchematic illustration of an innovative chemical approach to solvent removal during nanoencapsulation. Methyl propionate present in the aqueous continuous phase reacts with sodium hydroxide, thereby producing methanol and sodium propionate. Its alkaline hydrolysis allows the continuous extraction of the solvent out of nanoemulsion

  15. Alternative solvent-based methyl benzoate vortex-assisted dispersive liquid-liquid microextraction for the high-performance liquid chromatographic determination of benzimidazole fungicides in environmental water samples.

    Science.gov (United States)

    Santaladchaiyakit, Yanawath; Srijaranai, Supalax

    2014-11-01

    Vortex-assisted dispersive liquid-liquid microextraction using methyl benzoate as an alternative extraction solvent for extracting and preconcentrating three benzimidazole fungicides (i.e., carbendazim, thiabendazole, and fluberidazole) in environmental water samples before high-performance liquid chromatographic analysis has been developed. The selected microextraction conditions were 250 μL of methyl benzoate containing 300 μL of ethanol, 1.0% w/v sodium acetate, and vortex agitation speed of 2100 rpm for 30 s. Under optimum conditions, preconcentration factors were 14.5-39.0 for the target fungicides. Limits of detection were obtained in the range of 0.01-0.05 μg/L. The proposed method was then applied to surface water samples and the recovery evaluations at three spiked concentration levels of 5, 30, and 50 μg/L were obtained in the range of 77.4-110.9% with the relative standard deviation water samples.

  16. Natural deep eutectic solvents as new potential media for green technology

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Yuntao [Natural Products Laboratory, Institute of Biology, Leiden University, 2300 RA Leiden (Netherlands); Spronsen, Jaap van; Witkamp, Geert-Jan [Laboratory for Process Equipment, Delft University of Technology, Delft (Netherlands); Verpoorte, Robert [Natural Products Laboratory, Institute of Biology, Leiden University, 2300 RA Leiden (Netherlands); Choi, Young Hae, E-mail: y.choi@chem.leidenuniv.nl [Natural Products Laboratory, Institute of Biology, Leiden University, 2300 RA Leiden (Netherlands)

    2013-03-05

    Highlights: ► Natural products were used as a source for deep eutectic solvents and ionic liquids. ► We define own chemical and physical properties of natural deep eutectic solvents. ► Interaction between natural deep eutectic solvents and solutes was confirmed by NMR. ► The developed natural deep eutectic solvents were applied as green media. - Abstract: Developing new green solvents is one of the key subjects in Green Chemistry. Ionic liquids (ILs) and deep eutectic solvents, thus, have been paid great attention to replace current harsh organic solvents and have been applied to many chemical processing such as extraction and synthesis. However, current ionic liquids and deep eutectic solvents have still limitations to be applied to a real chemical industry due to toxicity against human and environment and high cost of ILs and solid state of most deep eutectic solvents at room temperature. Recently we discovered that many plant abundant primary metabolites changed their state from solid to liquid when they were mixed in proper ratio. This finding made us hypothesize that natural deep eutectic solvents (NADES) play a role as alternative media to water in living organisms and tested a wide range of natural products, which resulted in discovery of over 100 NADES from nature. In order to prove deep eutectic feature the interaction between the molecules was investigated by nuclear magnetic resonance spectroscopy. All the tested NADES show clear hydrogen bonding between components. As next step physical properties of NADES such as water activity, density, viscosity, polarity and thermal properties were measured as well as the effect of water on the physical properties. In the last stage the novel NADES were applied to the solubilization of wide range of biomolecules such as non-water soluble bioactive natural products, gluten, starch, and DNA. In most cases the solubility of the biomolecules evaluated in this study was greatly higher than water. Based on the

  17. A facile one-step solution deposition via non-solvent/solvent mixture for efficient organometal halide perovskite light-emitting diodes.

    Science.gov (United States)

    Jiao, Bo; Zhu, Xiaobo; Wu, Wen; Dong, Hua; Xia, Bin; Xi, Jun; Lei, Ting; Hou, Xun; Wu, Zhaoxin

    2016-06-01

    Although organometal halide perovskite materials have shown great potential in light-emitting diodes, their performance is greatly restricted by the poor morphology of the perovskite layer. In this work, we demonstrate a facile one-step solution method to improve the perovskite film morphology via a non-solvent/solvent mixture. An efficient CH3NH3PbBr3-based light-emitting diode was prepared with a chlorobenzene/N,N-dimethylformamide mixed solvent. A high efficiency of 0.54 cd A(-1) is demonstrated, which is 22 times higher than that of a device fabricated by a traditional one-step solution process. Furthermore, the uniformity of the emission region and the device stability are strongly improved by this facile one-step solution process. Our work paves a new way for the morphological control of perovskite films for application in light-emitting diodes.

  18. On the Integration Role of Solvents in Process Synthesis-Design-Intensification: Application to DMC/MeOH separation

    DEFF Research Database (Denmark)

    Gani, Rafiqul; Babi, Deenesh Kavi

    2015-01-01

    and the heavier boiling compound is obtained as the top product of the second distillation column where the solvent is recovered (for re-use and recycle). Therefore, the solvent design problem can be defined as follows, given an azeotropic mixture to be separated into two pure streams that utilizes a mass...... separating agent, find the best (optimal or near-optimal) solvent candidate (or mixture) that can perform the separation subject to economic, environmental and thermo-physical property constraints. This design problem inherently is a mixed integer non-linear programming problem because the property...... design problem into manageable sub-problems. In the first stage, a number of solvent candidates are generated based on pre-defined structural constraints, for example, acyclic, cyclic and/or aromatic compounds, etc. In the second stage, the solvent candidates are screened using property constraints...

  19. Preferential Solvation of a Highly Medium Responsive Pentacyanoferrate(II) Complex in Binary Solvent Mixtures: Understanding the Role of Dielectric Enrichment and the Specificity of Solute-Solvent Interactions.

    Science.gov (United States)

    Papadakis, Raffaello

    2016-09-08

    In this work, the preferential solvation of an intensely solvatochromic ferrocyanide(II) dye involving a 4,4'-bipyridine-based ligand was examined in various binary solvent mixtures. Its solvatochromic behavior was rationalized in terms of specific and nonspecific solute-solvent interactions. An exceptional case of solvatochromic inversion was observed when going from alcohol/water to amide/water mixtures. These effects were quantified using Onsager's solvent polarity function. Furthermore, the sensitivity of the solvatochromism of the dye was determined using various solvatochromic parameters such as π* expressing the dipolarity/polarizability of solvents and α expressing the hydrogen-bond-donor acidity of solvents. This analysis was useful for the rationalization of the selective solvation phenomena occurring in the three types of alcohol/water and amide/water mixtures studied. Furthermore, two preferential solvation models were employed for the interpretation of the experimental spectral results in binary solvent mixtures, namely, the model of Suppan on dielectric enrichment [J. Chem. Soc. Faraday Trans. 1 1987, 83, 495-509] and the model of Bosch, Rosés, and co-workers [J. Chem. Soc., Perkin Trans. 2, 1995, 8, 1607-1615]. The first model successfully predicted the charge transfer energies of the dye in formamide/water and N-methylformamide/water mixtures, but in the case of MeOH/water mixtures, the prediction was less accurate because of the significant contribution of specific solute-solvent interactions in that case. The second model gave more insights for both specific solute-solvent as well as solvent-solvent interactions in the cybotactic region. The role of dielectric enrichment and specific interactions was discussed based on the findings.

  20. Selection and evaluation of alternative solvents for caprolactam extraction

    NARCIS (Netherlands)

    Delden, van Mathijs L.; Kuipers, Norbert J.M.; Haan, de André B.

    2006-01-01

    Because of the strict legislation for currently applied solvents in the industrial extraction of caprolactam, being benzene, toluene and chlorinated hydrocarbons, a need exists for alternative, environmentally benign solvents. An experimental screening procedure consisting of several steps was used