The Role of Solvent Polarity on Low-Temperature Methanol Synthesis Catalyzed by Cu Nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Ahoba-Sam, Christian [Department of Process, Energy and Environmental Technology, University College of Southeast Norway, Porsgrunn (Norway); Olsbye, Unni [Department of Chemistry, University of Oslo, Oslo (Norway); Jens, Klaus-Joachim, E-mail: Klaus.J.Jens@usn.no [Department of Process, Energy and Environmental Technology, University College of Southeast Norway, Porsgrunn (Norway)

2017-07-14

Methanol syntheses at low temperature in a liquid medium present an opportunity for full syngas conversion per pass. The aim of this work was to study the role of solvents polarity on low-temperature methanol synthesis reaction using eight different aprotic polar solvents. A “once through” catalytic system, which is composed of Cu nanoparticles and sodium methoxide, was used for methanol synthesis at 100°C and 20 bar syngas pressure. Solvent polarity rather than the 7–10 nm Cu (and 30 nm Cu on SiO{sub 2}) catalyst used dictated trend of syngas conversion. Diglyme with a dielectric constant (ε) = 7.2 gave the highest syngas conversion among the eight different solvents used. Methanol formation decreased with either increasing or decreasing solvent ε value of diglyme (ε = 7.2). To probe the observed trend, possible side reactions of methyl formate (MF), the main intermediate in the process, were studied. MF was observed to undergo two main reactions; (i) decarbonylation to form CO and MeOH and (ii) a nucleophilic substitution to form dimethyl ether and sodium formate. Decreasing polarity favored the decarbonylation side reaction while increasing polarity favored the nucleophilic substitution reaction. In conclusion, our results show that moderate polarity solvents, e.g., diglyme, favor MF hydrogenolysis and, hence, methanol formation, by retarding the other two possible side reactions.

Effective visualization assay for alcohol content sensing and methanol differentiation with solvent stimuli-responsive supramolecular ionic materials.

Science.gov (United States)

Zhang, Li; Qi, Hetong; Wang, Yuexiang; Yang, Lifen; Yu, Ping; Mao, Lanqun

2014-08-05

This study demonstrates a rapid visualization assay for on-spot sensing of alcohol content as well as for discriminating methanol-containing beverages with solvent stimuli-responsive supramolecular ionic material (SIM). The SIM is synthesized by ionic self-assembling of imidazolium-based dication C10(mim)2 and dianionic 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) in water and shows water stability, a solvent stimuli-responsive property, and adaptive encapsulation capability. The rationale for the visualization assay demonstrated here is based on the combined utilization of the unique properties of SIM, including its water stability, ethanol stimuli-responsive feature, and adaptive encapsulation capability toward optically active rhodamine 6G (Rh6G); the addition of ethanol into a stable aqueous dispersion of Rh6G-encapsulated SIM (Rh6G-SIM) destructs the Rh6G-SIM structure, resulting in the release of Rh6G from SIM into the solvent. Alcohol content can thus be visualized with the naked eyes through the color change of the dispersion caused by the addition of ethanol. Alcohol content can also be quantified by measuring the fluorescence line of Rh6G released from Rh6G-SIM on a thin-layer chromatography (TLC) plate in response to alcoholic beverages. By fixing the diffusion distance of the mobile phase, the fluorescence line of Rh6G shows a linear relationship with alcohol content (vol %) within a concentration range from 15% to 40%. We utilized this visualization assay for on-spot visualizing of the alcohol contents of three Chinese commercial spirits and discriminating methanol-containing counterfeit beverages. We found that addition of a trace amount of methanol leads to a large increase of the length of Rh6G on TLC plates, which provides a method to identify methanol adulterated beverages with labeled ethanol content. This study provides a simple yet effective assay for alcohol content sensing and methanol differentiation.

Ejection of solvated ions from electrosprayed methanol/water nanodroplets studied by molecular dynamics simulations.

Science.gov (United States)

Ahadi, Elias; Konermann, Lars

2011-06-22

The ejection of solvated small ions from nanometer-sized droplets plays a central role during electrospray ionization (ESI). Molecular dynamics (MD) simulations can provide insights into the nanodroplet behavior. Earlier MD studies have largely focused on aqueous systems, whereas most practical ESI applications involve the use of organic cosolvents. We conduct simulations on mixed water/methanol droplets that carry excess NH(4)(+) ions. Methanol is found to compromise the H-bonding network, resulting in greatly increased rates of ion ejection and solvent evaporation. Considerable differences in the water and methanol escape rates cause time-dependent changes in droplet composition. Segregation occurs at low methanol concentration, such that layered droplets with a methanol-enriched periphery are formed. This phenomenon will enhance the partitioning of analyte molecules, with possible implications for their ESI efficiencies. Solvated ions are ejected from the tip of surface protrusions. Solvent bridging prior to ion secession is more extensive for methanol/water droplets than for purely aqueous systems. The ejection of solvated NH(4)(+) is visualized as diffusion-mediated escape from a metastable basin. The process involves thermally activated crossing of a ~30 kJ mol(-1) free energy barrier, in close agreement with the predictions of the classical ion evaporation model.

Effect of Dielectric Properties of a Solvent-Water Mixture Used in Microwave-Assisted Extraction of Antioxidants from Potato Peels

Directory of Open Access Journals (Sweden)

Ashutosh Singh

2014-02-01

Full Text Available The dielectric properties of a methanol-water mixture were measured at different temperatures from 20 to 80 °C at two frequencies 915 MHz and 2450 MHz. These frequencies are most commonly used on industrial and domestic scales respectively. In this study, the dielectric properties of a methanol-water mixture were found to be dependent on temperature, solvent concentration, and presence of plant matrix. Linear and quadratic equations were developed to establish the dependency between factors. At 2450 MHz, the dielectric constant of methanol-water mixtures was significantly affected by concentration of methanol rather than by temperature, whereas the dielectric loss factor was significantly affected by temperature rather than by methanol concentration. Introduction of potato peel led to an increase in the effect of temperature on the dielectric properties of the methanol fractions. At 915 MHz, both the dielectric properties were significantly affected by the increase in temperature and solvent concentration, while the presence of potato peel had no significant effect on the dielectric properties. Statistical analysis of the dissipation factor at 915 and 2450 MHz revealed that both temperature and solvent concentration had a significant effect on it, whereas introduction of potato peels at 915 MHz reduced the effect of temperature as compared to 2450 MHz. The total phenolic yield of the microwave-assisted extraction process was significantly affected by the solvent concentration, the dissipation factor of the methanol-water mixture and the extraction time.

Enthalpies of solvation of ethylene oxide oligomers CH{sub 3}O(CH{sub 2}CH{sub 2}O){sub n}CH{sub 3} (n = 1 to 4) in different H-bonding solvents: Methanol, chloroform, and water. Group contribution method as applied to the polar oligomers

Energy Technology Data Exchange (ETDEWEB)

Barannikov, Vladimir P., E-mail: vpb@isc-ras.ru [Institute of Solution Chemistry, Russian Academy of Sciences, Academicheskaya Str. 1, Ivanovo 153045 (Russian Federation); Guseynov, Sabir S.; Vyugin, Anatoliy I. [Institute of Solution Chemistry, Russian Academy of Sciences, Academicheskaya Str. 1, Ivanovo 153045 (Russian Federation)

2011-12-15

Highlights: > Solvation enthalpy is found for ethylene oxide oligomers in chloroform and methanol. > Coefficients of solute-solute interaction are determined for oligomers in methanol. > Enthalpies of hydrogen bonding of oligomers with chloroform and water are estimated. > Additivity scheme is developed for describing enthalpies of solvation of oligomers. - Abstract: The enthalpies of solution and solvation of ethylene oxide oligomers CH{sub 3}O(CH{sub 2}CH{sub 2}O){sub n}CH{sub 3} (n = 1 to 4) in methanol and chloroform have been determined from calorimetric measurements at T = 298.15 K. The enthalpic coefficients of pairwise solute-solute interaction for methanol solutions have been calculated. The enthalpic characteristics of the oligomers in methanol, chloroform, water and tetrachloromethane have been compared. The hydrogen bonding of the oligomers with chloroform and water molecules is exhibited in the values of solvation enthalpy and coefficient of solute-solute interaction. This effect is not observed for methanol solvent. The thermochemical data evidence an existence of multi-centred hydrogen bonds in associates of polyethers with the solvent molecules. Enthalpies of hydrogen bonding of the oligomers with chloroform and water have been estimated. The additivity scheme has been developed to describe the enthalpies of solvation of ethylene oxide oligomers, unbranched monoethers and n-alkanes in chloroform, methanol, water, and tetrachloromethane. The correction parameters for contribution of repeated polar groups and correction term for methoxy-compounds have been introduced. The obtained group contributions permit to describe the enthalpies of solvation of unbranched monoethers and ethylene oxide oligomers in the solvents with standard deviation up to 0.6 kJ . mol{sup -1}. The values of group contributions and corrections are strongly influenced by solvent properties.

Electrokinetic transport of water and methanol in Nafion membranes as observed by NMR spectroscopy

International Nuclear Information System (INIS)

Hallberg, Fredrik; Vernersson, Thomas; Pettersson, Erik Thyboll; Dvinskikh, Sergey V.; Lindbergh, Goeran; Furo, Istvan

2010-01-01

Electrophoretic NMR (eNMR) and pulsed-field-gradient NMR (PFG-NMR) methods were used to study transport processes in situ and in a chemically resolved manner in the electrolyte of an experimental direct methanol fuel cell (DMFC) setup, constituted of several layers of Nafion 117. The measurements were conducted at room temperature for membranes fully swollen by methanol-water mixtures over a wide concentration interval. The experimental setup and the experimental protocol for the eNMR experiments are discussed in detail. The magnitude of the water and methanol self-diffusion coefficients show a good agreement with previously published data while the ratio of the two self-diffusion coefficients may indicate an imperfect mixing of the two solvent molecules. On the molecular level, the drag of water and methanol molecules by protons is roughly of the same magnitude, with the drag of methanol molecules increasing with increasing methanol content. The electro-osmotic drag defined on mass-flow basis increased for methanol from a low level with increasing methanol concentration while that of water remained roughly constant.

Crystal structure of di-μ-chlorido-bis[dichloridobis(methanol-κOiridium(III] dihydrate: a surprisingly simple chloridoiridium(III dinuclear complex with methanol ligands

Directory of Open Access Journals (Sweden)

Joseph S. Merola

2015-05-01

Full Text Available The reaction between IrCl3·xH2O in methanol led to the formation of small amounts of the title compound, [Ir2Cl6(CH3OH4]·2H2O, which consists of two IrCl4O2 octahedra sharing an edge via chloride bridges. The molecule lies across an inversion center. Each octahedron can be envisioned as being comprised of four chloride ligands in the equatorial plane with methanol ligands in the axial positions. A lattice water molecule is strongly hydrogen-bonded to the coordinating methanol ligands and weak interactions with coordinating chloride ligands lead to the formation of a three-dimensional network. This is a surprising structure given that, while many reactions of iridium chloride hydrate are carried out in alcoholic solvents, especially methanol and ethanol, this is the first structure of a chloridoiridium compound with only methanol ligands.

Transfers of Colloidal Silica from Water into Organic Solvents of Intermediate Polarities

Science.gov (United States)

Kasseh; Keh

1998-01-15

Dispersions of discrete metal-oxide submicroparticles in organic solvents of medium polarities are uneasy to generate and weakly documented. We address this topic along two general methods focusing on silica. Successive transfers of colloidal particles from water into n-propanol and then into 1,2-dichloroethane by azeotropic distillation yield a stable organosol. The particles are found to be propanol-coated by surface esterification to the extent of 0.40 nm2 per molecule. Alternatively, centrifugation-redispersion cycles make it possible to obtain stable suspensions of unaltered silica in methanol and acetonitrile starting from an aqueous silicasol. Particles are characterized by various methods including nitrogen adsorption, transmission electron microscopy, dynamic light scattering, and electrophoresis. The stabilities of these suspensions in various organic solvents are investigated with special concern for the role of residual water. Stabilization of silica in methanol is inconspicuously related to solvent permittivity and prominently dependent on the presence of adsorbed water. In contrast, the acetonitrile silicasol, which is unaffected by residual water, displays electrophoretic behavior compatible with electrostatic stabilization. Copyright 1998 Academic Press. Copyright 1998Academic Press

Antioxidant Activities of Methanol Extract and Solvent Fractions of ...

African Journals Online (AJOL)

Purpose: To determine the antioxidant activity of methanol extract (ME) and solvent fractions of Avrainvillea erecta as well as their total phenolic and flavonoid contents. Methods: The antioxidant activities of ME as well as its chloroform, butanol, and aqueous fractions (CF, BF and WF, respectively) of A. erecta were ...

Solution thermodynamics and preferential solvation of sulfamethazine in (methanol + water) mixtures

International Nuclear Information System (INIS)

Delgado, Daniel R.; Almanza, Ovidio A.; Martínez, Fleming; Peña, María A.; Jouyban, Abolghasem; Acree, William E.

2016-01-01

Highlights: • Solubility of sulfamethazine (SMT) was measured in (methanol + water) mixtures. • SMT solubility was correlated with Jouyban–Acree model. • Gibbs energy, enthalpy, and entropy of dissolution of SMT were calculated. • Non-linear enthalpy–entropy relationship was observed for SMT. • Preferential solvation of SMT by methanol was analyzed by using the IKBI method. - Abstract: The solubility of sulfamethazine (SMT) in {methanol (1) + water (2)} co-solvent mixtures was determined at five different temperatures from (293.15 to 313.15) K. The sulfonamide exhibited its highest mole fraction solubility in pure methanol (δ 1 = 29.6 MPa 1/2 ) and its lowest mole fraction solubility in water (δ 2 = 47.8 MPa 1/2 ) at each of the five temperatures studied. The Jouyban–Acree model was used to correlate/predict the solubility values. The respective apparent thermodynamic functions Gibbs energy, enthalpy, and entropy of solution were obtained from the solubility data through the van’t Hoff and Gibbs equations. Apparent thermodynamic quantities of mixing were also calculated for this drug using values of the ideal solubility reported in the literature. A non-linear enthalpy–entropy relationship was noted for SMT in plots of both the enthalpy vs. Gibbs energy of mixing and the enthalpy vs. entropy of mixing. These plots suggest two different trends according to the slopes obtained when the composition of the mixtures changes. Accordingly, the mechanism for SMT transfer processes in water-rich mixtures from water to the mixture with 0.70 in mass fraction of methanol is entropy driven. Conversely, the mechanism is enthalpy driven in mixtures whenever the methanol composition exceeds 0.70 mol fraction. An inverse Kirkwood–Buff integral analysis of the preferential solvation of SMT indicated that the drug is preferentially solvated by water in water-rich mixtures but is preferentially solvated by methanol in methanol-rich mixtures.

Enhanced Crystallization by Methanol Additive in Anti-solvent for Achieving High-quality MAPbI3 Perovskite Films in Humid Atmosphere.

Science.gov (United States)

Yang, Fu; Kamarudin, Muhammad Akmal; Zhang, PuTao; Kapil, Gaurav; Ma, Tingli; Hayase, Shuzi

2018-05-04

Perovskite solar cells have attracted considerable attention owing to easy and low-cost solution manufacturing process with high power conversion efficiency. However, the fabrication process is usually performed inside glovebox to avoid the moisture, as organometallic halide perovskite is easily dissolved in water. In this study, we propose one-step fabrication of high-quality MAPbI3 perovskite films in 50 % RH humid ambient air by using diethyl ether as an anti-solvent and methanol as an additive into this anti-solvent. Because of the existence of methanol, the water molecules can be efficiently removed from the gaps of perovskite precursors and the perovskite film formation can be slightly controlled leading to pinhole-free and low roughness film. Concurrently, methanol can modify a proper DMSO ratio in the intermediate perovskite phase to regulate perovskite formation. Planar solar cells fabricated by using this method exhibited the best efficiency of 16.4 % with a reduced current density-voltage hysteresis. This efficiency value is approximately 160 % higher than the devices fabrication by using only diethyl ether treatment. From the impedance measurement, it is also found that the recombination reaction has been suppressed when the device prepared with additive anti-solvent way. This method presents a new path for controlling the growth and morphology of perovskite films in the humid climates and uncontrolled laboratories. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Activity coefficients, interfacial tensions and retention in reversed-phase liquid chormatography on LiChrosorb RP-18 with methanol-water mixtures

NARCIS (Netherlands)

Hammers, W.E.; Meurs, G.J.; Ligny, C.L. de

1982-01-01

Literature data on activity coefficients of various solutes in water, of some tetraalkyl compounds in methanol-water mixture and of water in organic solvents have been correlated with the product of the molecular surface area of the solute and the solute-solvent interfacial tension at ambient

Structural transition of a homopolymer in solvents mixture

International Nuclear Information System (INIS)

Guettari, Moez; Aschi, Adel; Gomati, Riadh; Gharbi, Abdelhafidh

2008-01-01

The present work is aimed at studying the thermodynamic behaviour of a polymer in solvents mixture. Dynamic light scattering is used to measure the hydrodynamic radius of polyvinylpyrrolidone (M w = 360,000 g/mol), in water/methanol solvents mixture, versus the mixed solvents composition at 25 deg. C. Then, we show that the polymer conformation adopts the Coil-Globule-Coil structure when the methanol molar fraction X A is varied. This transition is attributed to solvent quality change which result from water and methanol complex formation. The polymer contraction rate calculated for each composition takes its maximum value at X A = 0.17. Hildebrand theory assuming the solvents mixture as an equivalent solvent was used to analyze the change in mixed solvents quality. These changes can be attributed to dispersive forces in solvents mixture

Thermal properties of phosphoric acid-doped polybenzimidazole membranes in water and methanol-water mixtures

Energy Technology Data Exchange (ETDEWEB)

Nores-Pondal, Federico J.; Corti, Horacio R. [Grupo de Pilas de Combustible, Departamento de Fisica de la Materia Condensada, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica (CNEA), Av. General Paz 1499, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Buera, M. Pilar [Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Av. Cantilo s/n, Ciudad Universitaria (1428) Buenos Aires (Argentina)

2010-10-01

The thermal properties of phosphoric acid-doped poly[2-2'-(m-phenylene)-5-5' bi-benzimidazole] (PBI) and poly[2,5-benzimidazole] (ABPBI) membranes, ionomeric materials with promising properties to be used as electrolytes in direct methanol and in high temperature polymer electrolyte membrane (PEM) fuel cells, were studied by means of differential scanning calorimetry (DSC) technique in the temperature range from -145 C to 200 C. The DSC scans of samples equilibrated in water at different relative humidities (RH) and in liquid water-methanol mixtures were analyzed in relation to glass transition, water crystallization/melting and solvent desorption in different temperature regions. The thermal relaxation observed in the very low temperature region could be ascribed to the glass transition of the H{sub 3}PO{sub 4}-H{sub 2}O mixture confined in the polymeric matrix. After cooling the samples up to -145 C, frozen water was detected in PBI and ABPBI at different RH, although at 100% RH less amount of water had crystallized than that observed in Nafion membranes under the same conditions. Even more important is the fact that the freezing degree of water is much lower in ABPBI membranes equilibrated in liquid water-methanol mixtures than that observed for PBI and, in a previous study, for Nafion. Thus, apart from other well known properties, acid-doped ABPBI emerges as an excellent ionomer for applications in direct methanol fuel cells working in cold environments. (author)

N-terminal diproline and charge group effects on the stabilization of helical conformation in alanine-based short peptides: CD studies with water and methanol as solvent.

Science.gov (United States)

Goyal, Bhupesh; Srivastava, Kinshuk Raj; Durani, Susheel

2017-06-01

Protein folding problem remains a formidable challenge as main chain, side chain and solvent interactions remain entangled and have been difficult to resolve. Alanine-based short peptides are promising models to dissect protein folding initiation and propagation structurally as well as energetically. The effect of N-terminal diproline and charged side chains is assessed on the stabilization of helical conformation in alanine-based short peptides using circular dichroism (CD) with water and methanol as solvent. A1 (Ac-Pro-Pro-Ala-Lys-Ala-Lys-Ala-Lys-Ala-NH 2 ) is designed to assess the effect of N-terminal homochiral diproline and lysine side chains to induce helical conformation. A2 (Ac-Pro-Pro-Glu-Glu-Ala-Ala-Lys-Lys-Ala-NH 2 ) and A3 (Ac-dPro-Pro-Glu-Glu-Ala-Ala-Lys-Lys-Ala-NH 2 ) with N-terminal homochiral and heterochiral diproline, respectively, are designed to assess the effect of Glu...Lys (i, i + 4) salt bridge interactions on the stabilization of helical conformation. The CD spectra of A1, A2 and A3 in water manifest different amplitudes of the observed polyproline II (PPII) signals, which indicate different conformational distributions of the polypeptide structure. The strong effect of solvent substitution from water to methanol is observed for the peptides, and CD spectra in methanol evidence A2 and A3 as helical folds. Temperature-dependent CD spectra of A1 and A2 in water depict an isodichroic point reflecting coexistence of two conformations, PPII and β-strand conformation, which is consistent with the previous studies. The results illuminate the effect of N-terminal diproline and charged side chains in dictating the preferences for extended-β, semi-extended PPII and helical conformation in alanine-based short peptides. The results of the present study will enhance our understanding on stabilization of helical conformation in short peptides and hence aid in the design of novel peptides with helical structures. Copyright © 2017 European Peptide

Collection methodology evaluation and solvents analysis/mixtures solvents in the air in work ambient: methanol in MEG mixture (methanol 33%, ethanol 60% and gasoline 7%); Avaliacao de metodologia de coleta e analise de solventes/misturas de solventes no ar em ambiente de trabalho: metanol em mistura MEG (metanol 33%, etanol 60% e gasolina 7%)

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Luiza Maria Nunes

1995-07-01

This thesis presents a proposal for evaluation of collection and solvent/solvent mixtures analysis methodology for the air in the work environment by studying the following issues of present solvents: historical aspects; methanol - properties and toxicity; collection methodology evaluation, and gases and vapors analysis in the air; experimental data. The denominated mixture MEG - methanol, ethanol and gasoline is analyzed in terms of its chemical characteristics. The author concludes the work detaching that the methodology presented can only be used for short duration measurements in concentrations peaks studies.

Study on application of ethanolamine in NPP secondary water treatment

International Nuclear Information System (INIS)

Wang Lin; Xie Yang; Cui Huaiming

2013-01-01

Ethanolamine (ETA) is an organic amine which has stronger alkalinity and lower volatility than ammonia. The paper analyzes the influence of ETA used in the secondary system and calculates its distributing status at the different nodes of the secondary system. The study shows that ETA can enhance the pH value in liquid phase of vapor-liquid two phase regions, effectively inhibit the flow-accelerated corrosion, reduce the corrosion rate of the secondary system materials and improve the economy of the in-service nuclear power plants. It is concluded that ETA as a pH additive to the secondary side of pressurized water reactor is completely viable. (authors)

Structural transition of a homopolymer in solvents mixture

Energy Technology Data Exchange (ETDEWEB)

Guettari, Moez [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunisia (Tunisia)], E-mail: gtarimoez@yahoo.fr; Aschi, Adel; Gomati, Riadh; Gharbi, Abdelhafidh [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunisia (Tunisia)

2008-07-01

The present work is aimed at studying the thermodynamic behaviour of a polymer in solvents mixture. Dynamic light scattering is used to measure the hydrodynamic radius of polyvinylpyrrolidone (M{sub w} = 360,000 g/mol), in water/methanol solvents mixture, versus the mixed solvents composition at 25 deg. C. Then, we show that the polymer conformation adopts the Coil-Globule-Coil structure when the methanol molar fraction X{sub A} is varied. This transition is attributed to solvent quality change which result from water and methanol complex formation. The polymer contraction rate calculated for each composition takes its maximum value at X{sub A} = 0.17. Hildebrand theory assuming the solvents mixture as an equivalent solvent was used to analyze the change in mixed solvents quality. These changes can be attributed to dispersive forces in solvents mixture.

Thermodynamics of the amalgam cells {l_brace}Cs-amalgam|CsX (m)|AgX|Ag{r_brace} (X=Cl, Br, I) and primary medium effects in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures

Energy Technology Data Exchange (ETDEWEB)

Falciola, Luigi [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: luigi.falciola@unimi.it; Longoni, Giorgio [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy); Mussini, Patrizia R. [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: patrizia.mussini@unimi.it; Mussini, Torquato [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: torquato.mussini@unimi.it

2006-06-15

The potential difference E of the amalgam cell {l_brace}Cs{sub x}Hg{sub 1-x}|CsX (m)|AgX|Ag{r_brace} (X=Cl, Br, I) has been measured as a function of the mole fraction x{sub Cs} of Cs metal in amalgams and of the molality m of CsX in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures containing up to 0.75 mass fraction of the organic component, at the temperature 298.15K. The respective standard molal potential differences E{sub m}{sup o} have been determined together with the relevant activity coefficients {gamma}{sub +}/- as functions of the CsX molality. The found E{sub m}{sup o} values show a parabolic decrease with increasing proportion of the organic component in the solvent mixture. Analysis of the relevant primary medium effects upon CsX shows that the CsX transfer from the standard state in water to the standard state in the (aqueous+organic) mixture is always unfavoured, and the acetonitrile is the least unfavoured co-solvent studied. Analysis of the primary medium effect upon CsI in terms of Feakins and French's theory leads to a primary hydration number close to zero, which is consistent with the results of supplementary EXAFS experiments on Cs{sup +} and I{sup -} in (acetonitrile+water) solvent mixtures.

Equilibrium data on ethanol-water-solvent ternaries

Directory of Open Access Journals (Sweden)

I. Kirbaslar

2000-06-01

Full Text Available Experimental liquid-liquid equilibria of water-ethanol-1-nonanol and water-ethanol-1-decanol systems were investigated at 303.16± 0.20 K. The reliability of the experimental tie-line data was ascertained by using Othmer-Tobias and Hand plots. Distribution coefficients (Di and separation factors (S were evaluated for the immiscibility region. It is concluded that the solvents with high boiling point, 1-nonanol and 1-decanol, are suitable separating agents for dilute aqueous ethyl alcohol solutions.

ESR study of the effects of water, methanol, and ethanol on gamma-irradiation of starch

International Nuclear Information System (INIS)

Henderson, A.M.; Rudin, A.

1981-01-01

This investigation deals with the nature and relative abundance of stable radicals formed by gamma-irradiation of wheat starch at room temperature. Additions of equal weights of water, methanol, and ethanol were equally effective in reducing the content of stable radicals in starch which contained about 12% water before the additions. When, however, the starting material was dried starch with 2.9% initial water content additional water and methanol were better radical scavengers than ethanol. This difference is attributed to the superior ability of water and methanol to permeate the starch structure. Superficially different ESR spectra were obtained in products made by irradiating starch and starch that contained added water or methanol. Computer simulation of these spectra showed that they could be matched by superposition of the spectra of the same four component radicals, with some adjustments of relative intensities and peak widths. The structure of these radicals have been deduced from the spectral assignments and relative effects of the three solvents used on the intensities of the respective ESR spectra

Switchover of reactions of solvated electrons with nitrate ions and ammonium ions in propanol-water solvents

International Nuclear Information System (INIS)

Kang, T.B.; Freeman, G.R.

1993-01-01

The reaction rate constants of e s - with ammonium nitrate (∼0.1 mol m -3 ) in 1-propanol-water and 2-propanol-water binary solvents correspond to [e s - + (NO 3 - ) s ] reaction in the water-rich solvents, and to [e s - + (NH 4 + ) s ] reaction in alcohol-rich solvents. The overall rate constant is smaller in solvents with 40-99 mol% water, with a minimum at 70 mol% water. The Arrhenius temperature coefficient is 26 kJ mol -1 in each pure propanol solvent, increases to 29 kJ mol -1 at 40 mol% water, then decreases to 17 kJ mol -1 in pure water solvent. The high reaction rates in the single component solvents, alcohol or water, are limited mainly by solvent processes related to shear viscosity (diffusion) and dielectric relaxation (dipole reorientation). Rate constants reported for concentrated solutions (50-1000 mol m -3 ) of ammonium and nitrate salts in methanol have been quantitatively reinterpreted in terms of the ion atmosphere model. 28 refs., 5 figs., 2 tabs

The Effect of Acetone Amount Ratio as Co-Solvent to Methanol in Transesterification Reaction of Waste Cooking Oil

Science.gov (United States)

Julianto, T. S.; Nurlestari, R.

2018-04-01

The production of biodiesel from waste cooking oil by transesterification reaction using acetone as co-solvent has been carried out. This research studied the optimal amount ratio of acetone as co-solvent to methanol in the transesterification process using homogeneous alkaline catalyst KOH 1% (w/w) of waste cooking oil at room temperature for 15 minutes of reaction time. Mole ratio of waste cooking oil to methanol is 1:12. Acetone was added as co-solvent in varied amount ratio to methanol are 1:4, 1:2, and 1:1, respectively. The results of fatty acid methyl esters (FAME) were analysed using GC-MS instrument. The results showed that the optimal ratio is 1:4 with 99.93% of FAME yield.

Vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters

International Nuclear Information System (INIS)

Ahmed, Musahid; Ahmed, Musahid; Wilson, Kevin R.; Belau, Leonid; Kostko, Oleg

2008-01-01

In this work we report on the vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters. Clusters of methanol with water are generated via co-expansion of the gas phase constituents in a continuous supersonic jet expansion of methanol and water seeded in Ar. The resulting clusters are investigated by single photon ionization with tunable vacuum ultraviolet synchrotron radiation and mass analyzed using reflectron mass spectrometry. Protonated methanol clusters of the form (CH3OH)nH + (n=1-12) dominate the mass spectrum below the ionization energy of the methanol monomer. With an increase in water concentration, small amounts of mixed clusters of the form (CH3OH)n(H2O)H + (n=2-11) are detected. The only unprotonated species observed in this work are the methanol monomer and dimer. Appearance energies are obtained from the photoionization efficiency (PIE) curves for CH3OH +, (CH 3OH)2 +, (CH3OH)nH + (n=1-9), and (CH 3OH)n(H2O)H + (n=2-9 ) as a function of photon energy. With an increase in the water content in the molecular beam, there is an enhancement of photoionization intensity for methanol dimer and protonated methanol monomer at threshold. These results are compared and contrasted to previous experimental observations

Identification of the substrate radical intermediate derived from ethanolamine during catalysis by ethanolamine ammonia-lyase.

Science.gov (United States)

Bender, Güneş; Poyner, Russell R; Reed, George H

2008-10-28

Rapid-mix freeze-quench (RMFQ) methods and electron paramagnetic resonance (EPR) spectroscopy have been used to characterize the steady-state radical in the deamination of ethanolamine catalyzed by adenosylcobalamin (AdoCbl)-dependent ethanolamine ammonia-lyase (EAL). EPR spectra of the radical intermediates formed with the substrates, [1-13C]ethanolamine, [2-13C]ethanolamine, and unlabeled ethanolamine were acquired using RMFQ trapping methods from 10 ms to completion of the reaction. Resolved 13C hyperfine splitting in EPR spectra of samples prepared with [1-13C]ethanolamine and the absence of such splitting in spectra of samples prepared with [2-13C]ethanolamine show that the unpaired electron is localized on C1 (the carbinol carbon) of the substrate. The 13C splitting from C1 persists from 10 ms throughout the time course of substrate turnover, and there was no evidence of a detectable amount of a product like radical having unpaired spin on C2. These results correct an earlier assignment for this radical intermediate [Warncke, K., et al. (1999) J. Am. Chem. Soc. 121, 10522-10528]. The EPR signals of the substrate radical intermediate are altered by electron spin coupling to the other paramagnetic species, cob(II)alamin, in the active site. The dipole-dipole and exchange interactions as well as the 1-13C hyperfine splitting tensor were analyzed via spectral simulations. The sign of the isotropic exchange interaction indicates a weak ferromagnetic coupling of the two unpaired electrons. A Co2+-radical distance of 8.7 A was obtained from the magnitude of the dipole-dipole interaction. The orientation of the principal axes of the 13C hyperfine splitting tensor shows that the long axis of the spin-bearing p orbital on C1 of the substrate radical makes an angle of approximately 98 degrees with the unique axis of the d(z2) orbital of Co2+.

Conductivity Measurements of Alkali Metal Thiocyanates in Water-Methanol Mixtures; Mizu-metanoru kongoyoubai ni okeru arukari kinzoku chioshiansan`en no denki dendodo sokutei

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Kubota, Eiji.; Horimoto, Sanaki. [Shinshu University, Nagano (Japan). Faculty of Science

1999-03-10

The counductivity of several alkali nmetal thiocyanates in water-methanol mixtures was measured at 25degreeC. the data were analyzed using Lee-Wheaton theory for symmetrical electroyers to cbtain ion association constant, K{sub A}, limiting molar sonductivity, {Lambda}{sub 0}, and limiting ionic molar conductivity, lamnda{sub 0}{+-}. In all the solvent systems, calculated{lambda}{sub 0}{sup +} values of the alkali metal ions increase in the order L{sub i}{sup +}methanol was ca.0.4. The changes in {lambda}{sub 0}{+-} of these alkali metal ions and thiocyanate ion with the molar fraction of methanol agree with change in the viscosity of the solvent or the heat of mixing of wateer-methanol mixtures. These alkali metal thiocyanates from little or no ion aggregated in water and water-methanol mixtures. These alkali metal thiocyanates K{sub A}=15-24 dm{sup 3} mol{sub -1} in methanol. (author)

A Novel Mechanism for Chemical Sensing Based on Solvent-Fluorophore-Substrate Interaction: Highly Selective Alcohol and Water Sensor with Large Fluorescence Signal Contrast.

Science.gov (United States)

Chung, Kyeongwoon; Yang, Da Seul; Jung, Jaehun; Seo, Deokwon; Kwon, Min Sang; Kim, Jinsang

2016-10-06

Differentiation of solvents having similar physicochemical properties, such as ethanol and methanol, is an important issue of interest. However, without performing chemical analyses, discrimination between methanol and ethanol is highly challenging due to their similarity in chemical structure as well as properties. Here, we present a novel type of alcohol and water sensor based on the subtle differences in interaction among solvent analytes, fluorescent organic molecules, and a mesoporous silica gel substrate. A gradual change in the chemical structure of the fluorescent diketopyrrolopyrrole (DPP) derivatives alters their interaction with the substrate and solvent analyte, which creates a distinct intermolecular aggregation of the DPP derivatives on the silica gel substrate depending on the solvent environment and produces a change in the fluorescence color and intensity as a sensory signal. The devised sensor device, which is fabricated with simple drop-casting of the DPP derivative solutions onto a silica gel substrate, exhibited a completely reversible fluorescence signal change with large fluorescence signal contrast, which allows selective solvent detection by simple optical observation with the naked eye under UV light. Superior selectivity of the alcohol and water sensor system, which can clearly distinguish among ethanol, methanol, ethylene glycol, and water, is demonstrated.

Cm3+-F- interaction in a mixed system of methanol and water

International Nuclear Information System (INIS)

Satoh, I.; Watanabe, T.; Ishii, Y.; Kawasaki, M.; Suganuma, H.

2003-01-01

The stability constants (β 1 ) of the monofluoro complex of Cm(III) have been determined in mixed solvents of methanol and water using the solvent extraction technique. The values of Inβ 1 increase as the molar fraction of methanol (X s ) in the mixed solvent increases. The variation in the stability constants mainly depends on the solvation of F - and slightly depends on both (1) the solvation of cations in connection with the complexation of CmF 2+ and (2) the electrostatic attraction of Cm 3+ -F - . The variation in Inβ 1 for Cm(III) due to the effect of both (1) and (2) is similar to that for Sm(III). By variation of Inβ 1 the coordination number in the primary hydration sphere (CN) of Cm(III) decreased from a value between CN = 9 and CN = 8 to CN = 8, at about X s = 0.02. The X s value of the inflection point of the CN for Cm is slightly lower than X s = 0.06 for Sm(III) and X s = 0.03 for Eu(III), previously obtained. (author)

Phase behaviour of heavy petroleum fractions in pure propane and n-butane and with methanol as co-solvent

International Nuclear Information System (INIS)

Canziani, D.; Ndiaye, P.M.; Franceschi, Elton; Corazza, Marcos L.; Vladimir Oliveira, J.

2009-01-01

This work reports phase equilibrium experimental results for heavy petroleum fractions in pure propane and n-butane as primary solvents and using methanol as co-solvent. Three kinds of oils were investigated from Marlim petroleum: a relatively light fraction coming from the first distillation of crude petroleum at atmospheric pressure (GOP - heavy gas oil of petroleum), the residue of such distillation (RAT) and the crude petroleum sample. Phase equilibrium measurements were performed in a high-pressure, variable-volume view cell, following the static synthetic method, over the temperature range of 323 K to 393 K, pressures up to 10 MPa and overall compositions of heavy component varying from 1 wt% to 40 wt%. Transition pressures for low methanol and oil concentrations were very close for GOP, RAT, and crude Marlim when using propane as the primary solvent. Close to propane critical temperature, two and three-phase transitions were observed for GOP and Marlim when methanol was increased. When n-butane was used as primary solvent, all transitions observed were of (vapour + liquid) type with transition pressure values smaller than those obtained for propane.

Effect of methanol ratio in mixed solvents on optical properties and wettability of ZnO films by cathodic electrodeposition

International Nuclear Information System (INIS)

Zhang, Miao; Xu, Kai; Jiang, Xishun; Yang, Lei; He, Gang; Song, Xueping; Sun, Zhaoqi; Lv, Jianguo

2014-01-01

Highlights: • Different surface morphologies of ZnO films were prepared by cathodic electrodeposition. • The surface morphologies are controlled through add different ratio methanol to electrolyte. • The morphology changes from nanorods with hexagonal structure to net-like nanostructure. • The wettability of films shows obvious change with increasing methanol ratio. • The maximum light-induced CA change has been observed with the methanol ratio of 0.8. - Abstract: ZnO thin films were prepared in the electrolyte with different methanol ratio by cathodic electrodeposition method. Microstructure, surface morphology, optical properties and wettability of the thin films were investigated by X-ray diffractometer, field-emission scanning electron microscope, ultraviolet–visible spectroscope, fluorescence spectrometer and water contact angle apparatus. Increase of methanol ratio in the solvents may restrain the (0 0 2) plane preferential orientation in some extent. Change of current density curves with the ratio of methanol in the solution play a vital role on electrochemical reaction kinetics, microstructure and/or surface morphology of ZnO thin films. With the methanol ratio increase from 0 to 0.8, the surface morphology changes from nanorods to net-like nanostructure. The adsorbed NO 3 − ions on the polar planes hinder the crystal growth along the c-axis and redirect the growth direction along the nonpolar planes. The maximum and minimum band gaps have been obtained in the ZnO thin films with the methanol ratio of 0.4 and 0.6, respectively. Change of contact angle before UV irradiation may be related to surface morphology and oxygen vacancies. The maximum light-induced water contact angle change has been observed in the sample with the methanol ratio of 0.8. The results may be attributed to the higher surface roughness and net-like morphology

Effect of methanol ratio in mixed solvents on optical properties and wettability of ZnO films by cathodic electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Zhang, Miao; Xu, Kai; Jiang, Xishun; Yang, Lei; He, Gang; Song, Xueping [School of Physics and Material Science, Anhui University, Hefei 230601 (China); Sun, Zhaoqi, E-mail: szq@ahu.edu.cn [School of Physics and Material Science, Anhui University, Hefei 230601 (China); Lv, Jianguo, E-mail: lvjg1@163.com [School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 (China)

2014-12-05

Highlights: • Different surface morphologies of ZnO films were prepared by cathodic electrodeposition. • The surface morphologies are controlled through add different ratio methanol to electrolyte. • The morphology changes from nanorods with hexagonal structure to net-like nanostructure. • The wettability of films shows obvious change with increasing methanol ratio. • The maximum light-induced CA change has been observed with the methanol ratio of 0.8. - Abstract: ZnO thin films were prepared in the electrolyte with different methanol ratio by cathodic electrodeposition method. Microstructure, surface morphology, optical properties and wettability of the thin films were investigated by X-ray diffractometer, field-emission scanning electron microscope, ultraviolet–visible spectroscope, fluorescence spectrometer and water contact angle apparatus. Increase of methanol ratio in the solvents may restrain the (0 0 2) plane preferential orientation in some extent. Change of current density curves with the ratio of methanol in the solution play a vital role on electrochemical reaction kinetics, microstructure and/or surface morphology of ZnO thin films. With the methanol ratio increase from 0 to 0.8, the surface morphology changes from nanorods to net-like nanostructure. The adsorbed NO{sub 3}{sup −} ions on the polar planes hinder the crystal growth along the c-axis and redirect the growth direction along the nonpolar planes. The maximum and minimum band gaps have been obtained in the ZnO thin films with the methanol ratio of 0.4 and 0.6, respectively. Change of contact angle before UV irradiation may be related to surface morphology and oxygen vacancies. The maximum light-induced water contact angle change has been observed in the sample with the methanol ratio of 0.8. The results may be attributed to the higher surface roughness and net-like morphology.

Soil and groundwater remediation guidelines for methanol

International Nuclear Information System (INIS)

2010-12-01

Methanol is used by oil and gas operators to inhibit hydrate formation in the recovery of heavy oils, in natural gas production and transport, as well as in various other production applications. Emissions from methanol primary occur from miscellaneous solvent usage, methanol production, end-product manufacturing, and storage and handling losses. This document provided soil and groundwater remediation guidelines for methanol releases into the environment. The guidelines were consistent with the Alberta Environment tier 1 soil and groundwater framework. The chemical and physical properties of methanol were reviewed. The environmental fate and behavior of methanol releases was discussed, and the behaviour and effects of methanol in terrestrial and aquatic biota were evaluated. The toxicity of methanol and its effects in humans and mammalian species were reviewed. Soil quality and ground water quality guidelines were presented. Surface water and soil guideline calculation methods were provided, and ecological exposure and ground water pathways were discussed. Management limits for methanol concentrations were also provided. 162 refs., 18 tabs., 4 figs.

Comparison of methanol and isopropanol as wash solvents for determination of hair cortisol concentration in grizzly bears and polar bears.

Science.gov (United States)

Kroshko, Thomas; Kapronczai, Luciene; Cattet, Marc R L; Macbeth, Bryan J; Stenhouse, Gordon B; Obbard, Martyn E; Janz, David M

2017-01-01

Methodological differences among laboratories are recognized as significant sources of variation in quantification of hair cortisol concentration (HCC). An important step in processing hair, particularly when collected from wildlife, is the choice of solvent used to remove or "wash" external hair shaft cortisol prior to quantification of HCC. The present study systematically compared methanol and isopropanol as wash solvents for their efficiency at removing external cortisol without extracting internal hair shaft cortisol in samples collected from free-ranging grizzly bears and polar bears. Cortisol concentrations in solvents and hair were determined in each of one to eight washes of hair with each solvent independently. •There were no significant decreases in internal hair shaft cortisol among all eight washes for either solvent, although methanol removed detectable hair surface cortisol after one wash in grizzly bear hair whereas hair surface cortisol was detected in all eight isopropanol washes.•There were no significant differences in polar bear HCC washed one to eight times with either solvent, but grizzly bear HCC was significantly greater in hair washed with isopropanol compared to methanol.•There were significant differences in HCC quantified using different commercial ELISA kits commonly used for HCC determinations.

Effect of solvent on crystallization behavior of xylitol

Science.gov (United States)

Hao, Hongxun; Hou, Baohong; Wang, Jing-Kang; Lin, Guangyu

2006-04-01

Effect of organic solvents content on crystallization behavior of xylitol was studied. Solubility and crystallization kinetics of xylitol in methanol-water system were experimentally determined. It was found that the solubility of xylitol at various methanol content all increases with increase of temperature. But it decreases when increasing methanol content at constant temperature. Based on the theory of population balance, the nucleation and growth rates of xylitol in methanol-water mixed solvents were calculated by moments method. From a series of experimental population density data of xylitol gotten from a batch-operated crystallizer, parameters of crystal nucleation and growth rate equations at different methanol content were got by the method of nonlinear least-squares. By analyzing, it was found that the content of methanol had an apparent effect on nucleation and growth rate of xylitol. At constant temperature, the nucleation and growth rate of xylitol all decrease with increase of methanol content.

Crystal structure of trans-N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyloxamide methanol monosolvate

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Miguel-Ángel Velázquez-Carmona

2016-07-01

Full Text Available The here crystallized oxamide was previously characterized as an unsolvated species [Jímenez-Pérez et al. (2000. J. Organomet. Chem. 614–615, 283–293], and is now reported with methanol as a solvent of crystallization, C30H44N2O4·CH3OH, in a different space group. The introduction of the solvent influences neither the molecular symmetry of the oxamide, which remains centrosymmetric, nor the molecular conformation. However, the unsolvated molecule crystallized as an ordered system, while many parts of the solvated crystal are disordered. The hydroxy group in the oxamide is disordered over two chemically equivalent positions, with occupancies 0.696 (4:0.304 (4; one tert-butyl group is disordered by rotation about the C—C bond, and was modelled with three sites for each methyl group, each one with occupancy 1/3. Finally, the methanol solvent, which lies on a twofold axis, is disordered by symmetry. The disorder affecting hydroxy groups and the solvent of crystallization allows the formation of numerous supramolecular motifs using four hydrogen bonds, with N—H and O—H groups as donors and the oxamide and methanol molecule as acceptors.

Solubility and preferential solvation of some n-alkyl-parabens in methanol + water mixtures at 298.15 K

International Nuclear Information System (INIS)

Cárdenas, Zaira J.; Jiménez, Daniel M.; Delgado, Daniel R.; Almanza, Ovidio A.; Jouyban, Abolghasem; Martínez, Fleming; Acree, William E.

2017-01-01

Highlights: • Parabens equilibrium solubility was determined in methanol + water binary mixtures at 298.15 K. • Solubility values were correlated with the Jouyban-Acree model. • Preferential solvation parameters were derived by using the IKBI method. • δx 1,3 values are negative in water-rich mixtures but positive in the other mixtures. - Abstract: Methyl, ethyl and propyl parabens equilibrium solubility was determined in (methanol + water) binary mixtures at 298.15 K. The mole fraction solubility of these compounds increased in 503 (from 2.40 × 10 −4 to 0.121), 1377 (from 9.86 × 10 −5 to 0.136) and 4597 (from 3.73 × 10 −5 to 0.171) times when passing from neat water to neat methanol, for methyl, ethyl and propyl parabens, respectively. All these solubility values were correlated with the Jouyban-Acree model. Preferential solvation parameters by methanol (δx 1,3 ) of these parabens were derived from their thermodynamic solution properties using the inverse Kirkwood-Buff integrals (IKBI) method. For all compounds δx 1,3 values are negative in water-rich mixtures but positive in mixtures with methanol mole fraction greater than 0.32. It is conjecturable that in the former case the hydrophobic hydration around non-polar groups of parabens plays a relevant role in the solvation. Besides, the preferential solvation of these solutes by methanol in mixtures of similar co-solvent compositions and in methanol-rich mixtures could be explained in terms of the higher basic behaviour of methanol.

Calorimetric determination of enthalpies for the proton ionization of N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid (BES) and N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid (TES) in water-methanol mixtures

International Nuclear Information System (INIS)

Bulos, B.N.; Jumean, F.H.

2004-01-01

The enthalpies of proton ionization of the biochemical buffers N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid (BES) and N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid (TES) were obtained in water-methanol mixtures in which the methanol mole fraction (X m ) varied in the range 0-0.36. For both buffers, ionization enthalpy for the first proton (ΔH 1 ) was small in all solvent media. However, upon addition of methanol, ΔH 2 increased steadily from 22.2 to a maximum of 27.2 kJ mol -1 for BES, whereas for TES it varied from 30.0 to 32.4, with a minimum of 28.6 kJ mol -1 at X m =0.123. It is noteworthy that this solvent composition lies within the region of maximum structure enhancement of water by methanol. The results were interpreted in terms of methanol-water interactions

The effect of thermodynamic properties of solvent mixtures explains the difference between methanol and ethanol in C.antarctica lipase B catalyzed alcoholysis.

Science.gov (United States)

Sasso, Francesco; Kulschewski, Tobias; Secundo, Francesco; Lotti, Marina; Pleiss, Jürgen

2015-11-20

Kinetic modelling, molecular modelling, and experimental determination of the initial reaction velocity of lipase-catalyzed alcoholysis were combined to study the effect of the alcohol substrate to catalytic activity. The model system consisted of methanol or ethanol at varying concentrations, vinyl acetate as ester substrate 15.2% (v/v), toluene as organic solvent, water at a controlled thermodynamic activity of 0.09, and C. antarctica lipase B as enzyme. For both alcohol substrates, the initial reaction velocity increased sharply at low concentrations and reached a maximum at 0.7% (v/v) for methanol and 2% (v/v) for ethanol. For higher concentrations, the reaction rate decreased to a level of 74% and 60% of the peak value, respectively, due to substrate inhibition. The concentration dependency was described by a kinetic model, including a ping-pong bi-bi mechanism and competitive inhibition by the alcohol, and confirmed previous observations that methanol is more efficiently inhibiting the enzyme than ethanol. However, if the initial reaction velocity was expressed in terms of thermodynamic activity of the two alcohol substrates, the maximum of initial reaction velocity was similar for methanol (a MeOH(max)=0.19) and ethanol (a EtOH(max)=0.21). This was confirmed by molecular modelling which resulted in similar KM (0.22 and 0.19) and Ki values (0.44 and 0.49) for methanol and ethanol, respectively, if expressed in thermodynamic activities. Thus, the experimentally observed difference between methanol and ethanol is not due to differences in interaction with the enzyme but is a consequence of the thermodynamics of the substrate-solvent mixture. For low concentrations in toluene, the activity coefficient of methanol is 40% higher than the activity coefficient of ethanol (γ MeOH=8.5, γ EtOH=6.1). Copyright © 2015 Elsevier B.V. All rights reserved.

Molecular dynamics simulations to examine structure, energetics, and evaporation/condensation dynamics in small charged clusters of water or methanol containing a single monatomic ion.

Science.gov (United States)

Daub, Christopher D; Cann, Natalie M

2012-11-01

We study small clusters of water or methanol containing a single Ca(2+), Na(+), or Cl(-) ion with classical molecular dynamics simulations, using models that incorporate polarizability via the Drude oscillator framework. Evaporation and condensation of solvent from these clusters is examined in two systems, (1) for isolated clusters initially prepared at different temperatures and (2) those with a surrounding inert (Ar) gas of varying temperature. We examine these clusters over a range of sizes, from almost bare ions up to 40 solvent molecules. We report data on the evaporation and condensation of solvent from the clusters and argue that the observed temperature dependence of evaporation in the smallest clusters demonstrates that the presence of heated gas alone cannot, in most cases, solely account for bare ion production in electrospray ionization (ESI), neglecting the key contribution of the electric field. We also present our findings on the structure and energetics of the clusters as a function of size. Our data agree well with the abundant literature on hydrated ion clusters and offer some novel insight into the structure of methanol and ion clusters, especially those with a Cl(-) anion, where we observe the presence of chain-like structures of methanol molecules. Finally, we provide some data on the reparameterizations necessary to simulate ions in methanol using the separately developed Drude oscillator models for methanol and for ions in water.

Calorimetric determination of enthalpies for the proton ionization of N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid (BES) and N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid (TES) in water-methanol mixtures

Energy Technology Data Exchange (ETDEWEB)

Bulos, B.N.; Jumean, F.H

2004-02-19

The enthalpies of proton ionization of the biochemical buffers N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid (BES) and N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid (TES) were obtained in water-methanol mixtures in which the methanol mole fraction (X{sub m}) varied in the range 0-0.36. For both buffers, ionization enthalpy for the first proton ({delta}H{sub 1}) was small in all solvent media. However, upon addition of methanol, {delta}H{sub 2} increased steadily from 22.2 to a maximum of 27.2 kJ mol{sup -1} for BES, whereas for TES it varied from 30.0 to 32.4, with a minimum of 28.6 kJ mol{sup -1} at X{sub m}=0.123. It is noteworthy that this solvent composition lies within the region of maximum structure enhancement of water by methanol. The results were interpreted in terms of methanol-water interactions.

Solubility of 3-Caffeoylquinic Acid in Different Solvents at 291-340 K

Science.gov (United States)

Wang, Y. T.; Zhang, C. L.; Cheng, X. L.; Zhao, J. H.; Wang, L. C.

2017-12-01

Using a laser monitoring observation technique the solubilities of 3-caffeoylquinic acid in pure solvents, water, methanol, ethanol, 1-propanol, 1-butanol, and two mixed solvents, methanol + water, ethanol + water have been determined at temperature range from 291-340 K. The experimental data were correlated by the modified Apelblat equation, λ h equation, and ideal model. The calculated solubilities were turned out very consistent with the experimental results, and the modified Apelblat equation shows the best agreement.

The coordination number of Lu(III) in a mixed system of methanol and water

International Nuclear Information System (INIS)

Arisaka, M.; Takuwa, N.; Suganuma, H.

2000-01-01

The stability constants (β 1(F) ) of the monofluoro complex of Lu(III) and those (β 1(Cl) ) of the monochloride solvent-shared ion-pair of Lu(III) have been determined in mixed solvents of methanol and water at 0.10 and 1.00 mol x dm -3 ionic strengths, respectively. The variation in lnβ 1(F) with an increase in the mole fraction of methanol (X s ) in the mixed solvent system showed an acute-angled convex inflection point at X s ∼ 0.12, an acute-angled concave inflection point at X s ∼ 0.22, and another acute-angled convex inflection point at X s ∼ 0.27. It was concluded that the first and the second convex inflection points denoted the CN of Lu 3+ from CN = 8 to a mixture of CN = 8 and 7 and from CN = 8 and 7 to a mixture containing CN = 6, respectively. The concave point is the starting point of a change in the CN of Lu(III) in LuF 2+ from CN = 8 to a mixture of CN = 8 and 7. The values at two inflection points of the CN around Lu 3+ are consistent with the inflection points of the variation in the values of lnβ 1(Cl ) versus the dielectric constant of the mixed solvent. (author)

Effect of di-butyl phosphate on flash point of PUREX solvent

International Nuclear Information System (INIS)

Srivastav, Ravi Kant; Kumar, Shekhar; Balasubramonian, S.; Kamachi Mudali, U.; Natarajan, R.

2015-01-01

30% Tri-n-butyl phosphate (TBP) in a aliphatic diluent is used as a solvent for PUREX process. This diluent is essentially equivalent to commercial dodecane. The radiolytic and acidic degradation of TBP forms di-butyl phosphate (DBP) which is detrimental to the performance of the solvent during nuclear fuel reprocessing operations. To study the possible effect of DBP on the flashpoint of PUREX solvent, synthetic solutions were made by adding DBP and flashpoints of resultant mixtures were determined with an automatic flashpoint tester as per ASTM procedures. Experimental results indicated virtually no effect of DBP on flash point of PUREX solvent in the concentration ranges of 0-16 g/L DBP. (author)

Solubility of cefoxitin acid in different solvent systems

International Nuclear Information System (INIS)

Yuan, Fuhong; Wang, Yongli; Xiao, Liping; Huang, Qiaoyin; Xu, Jinchao; Jiang, Chen; Hao, Hongxun

2016-01-01

Highlights: • The solubility of cefoxitin acid in different solvent systems was measured. • Three models were used to correlate the solubility data. • The dissolution enthalpy of the dissolution process was calculated. - Abstract: Cefoxitin acid is one kind of important pharmaceutical intermediate. Its solubility is crucial for designing and optimizing the crystallization processes. In this work, the solubility of cefoxitin acid in organic solvents (methanol, acetonitrile, ethanol, isopropanol, n-propanol and ethyl acetate), water and water-methanol mixtures was measured spectrophotometrically using a shake-flask method within the temperature range 278.15–303.15 K. PXRD data and the Karl Fischer method were used to verify the crystal form stability of cefoxitin acid in the solubility measuring process. The melting points, the enthalpy and entropy of fusion were estimated. Results showed that the solubility of cefoxitin acid increases with the increasing temperature in all tested solvents in this work, and the solubility of cefoxitin acid increases with the increasing methanol concentration in water-methanol mixtures. The experimental solubility values were well correlated using the modified Apelblat equation, NRTL model and CNIBS/R-K model. An equation proposed by Williamson was adopted to calculate the molar enthalpy during the dissolution process.

Effect of extraction solvents on polyphenols and antioxidant activity of medicinal halophytes

International Nuclear Information System (INIS)

Qasim, M.; Aziz, I.; Gul, B.

2016-01-01

This study was conducted to determine the most effective solvent for extraction of polyphenols and antioxidant activity of medicinally important coastal halophytes (Thespesia populneoides, Salvadora persica, Ipomoea pes-caprae, Suaeda fruticosa and Pluchea lanceolata) known for high antioxidant potential. Five different solvents (water, 80% methanol, 80% ethanol, acetone and chloroform) were used to quantify polyphenols including total phenolic (TPC), total flavonoid (TFC) and proanthocyanidin contents (PC) and antioxidant capacity using DPPH radical scavenging and Ferric reducing antioxidant power (FRAP) activities. Among solvents of different polarities 80% methanol appeared most effective for polyphenol extraction. Thespesia populneoides had the highest polyphenols (TPC, TFC and PC) followed by Salvadora persica. Highest antioxidant activity was also found in T. populneoides and S. persica using the same solvent (80% methanol) which appeared better than synthetic antioxidants (BHA and BHT). The correlation analyses of each solvent showed strong to weak relationships among all studied parameters with maximum values (r and R2) in methanol followed by ethanol and water. Weaker correlation of acetone and chloroform indicates low capacity of these solvents both for polyphenol extraction and antioxidant activity. Our results reveal that aqueous methanol extracts of coastal halophytes had comparatively higher antioxidant activity than commercial antioxidants which indicate both their prospective efficacy and potential to replace synthetic derivatives from edible and medicinal products. (abstract)

METHANOL REMOVAL FROM METHANOL-WATER MIXTURE USING ACTIVATED SLUDGE, AIR STRIPPING AND ADSORPTION PROCESS: COMPARATIVE STUDY

Directory of Open Access Journals (Sweden)

SALAM K. AL-DAWERY

2015-12-01

Full Text Available An experimental research has been carried out in order to examine the removal of methanol from methanol-water mixtures using three different methods; activated sludge; activated carbon and air stripping. The results showed that the methanol was totally consumed by the bacteria as quickly as the feed entered the activated sludge vessel. Air stripping process has a limited ability for removing of methanol due to strong intermolecular forces between methanol and water; however, the results showed that the percentage of methanol removed using air pressure at 0.5 bar was higher than that of using air pressure of 0.25 bar. Removal of methanol from the mixture with a methanol content of 5% using activated carbon was not successful due to the limited capacity of the of the activated carbon. Thus, the activated sludge process can be considered as the most suitable process for the treatment of methanol-water mixtures.

Dissolution behavior of silk fibroin in a low concentration CaCl2-methanol solvent: From morphology to nanostructure.

Science.gov (United States)

Shen, Tingting; Wang, Tao; Cheng, Guotao; Huang, Lan; Chen, Lei; Wu, Dayang

2018-02-05

Regenerated Silk biomaterials are usually pre-formed from silk fibroin solutions. However, the dissolution of silk fibroin in proper solvents by a simple and low cost way is still a challenge. Here, we employed a CaCl 2 -methanol solvent system with a very low CaCl 2 concentration of 6wt% to dissolve silk fibroin. During the dissolution process, the evaporation of methanol cause the changing of solvation sheath of ions in the solvent. The remaining solvent with the incomplete solvation sheath is absorbed by the silk fiber and interacts with fibroin chains to complete the solvation sheath, which accounts for the dissolution of silk fibroin. Silk fibroin dissolution stops as all the solvation sheaths are complete. The final CaCl 2 concentration is ca. 26% and silk fibroin is completely dissolved with a yield of about 90%. Silk fibroin is dissolved into multi-scale nanofibrils solution which is potential for producing regenerated silk fibroin materials for functional applications. Copyright © 2018. Published by Elsevier B.V.

Effect of Ethanolamines on Corrosion Inhibition of Ductile Cast Iron in Nitrite Containing Solutions

International Nuclear Information System (INIS)

Kim, K. T.; Kim, Y. S.; Chang, H. Y.; Lim, B. T.; Park, H. B.

2016-01-01

In this work, synergistic corrosion inhibition effect of nitrite and 3 kinds of ethanolamines on ductile cast iron using chemical and electrochemical methods was evaluated. This work attempts to clarify the synergistic effect of nitrite and ethanolamines. The effects of single addition of TEA, DEA, and MEA, and mixed addition of nitrite plus TEA, DEA or MEA on the corrosion inhibition of ductile cast iron in a tap water were evaluated. A huge amount of single addition of ethanolamine was needed. However, the synergistic effect by mixed addition was observed regardless of the combination of nitrite and triethanolamines, but their effects increased in a series of MEA + nitrite > DEA + nitrite > TEA + nitrite. This tendency of synergistic effect was attributed to the film properties and polar effect; TEA addition couldn't form the film showing high film resistance and semiconductive properties, but DEA or MEA could build the film having relatively high film resistance and n-type semiconductive properties. Moreover, it can be explained that this behaviour was closely related to electron attractive group within the ethanolamines, and thus corrosion inhibition power depends upon the number of the electron attractive group of MEA, DEA, and TEA.

Effect of Ethanolamines on Corrosion Inhibition of Ductile Cast Iron in Nitrite Containing Solutions

Energy Technology Data Exchange (ETDEWEB)

Kim, K. T.; Kim, Y. S. [Andong National University, Andong (Korea, Republic of); Chang, H. Y.; Lim, B. T.; Park, H. B. [KEPCO Engineering and Construction Company, Gimcheon (Korea, Republic of)

2016-08-15

In this work, synergistic corrosion inhibition effect of nitrite and 3 kinds of ethanolamines on ductile cast iron using chemical and electrochemical methods was evaluated. This work attempts to clarify the synergistic effect of nitrite and ethanolamines. The effects of single addition of TEA, DEA, and MEA, and mixed addition of nitrite plus TEA, DEA or MEA on the corrosion inhibition of ductile cast iron in a tap water were evaluated. A huge amount of single addition of ethanolamine was needed. However, the synergistic effect by mixed addition was observed regardless of the combination of nitrite and triethanolamines, but their effects increased in a series of MEA + nitrite > DEA + nitrite > TEA + nitrite. This tendency of synergistic effect was attributed to the film properties and polar effect; TEA addition couldn't form the film showing high film resistance and semiconductive properties, but DEA or MEA could build the film having relatively high film resistance and n-type semiconductive properties. Moreover, it can be explained that this behaviour was closely related to electron attractive group within the ethanolamines, and thus corrosion inhibition power depends upon the number of the electron attractive group of MEA, DEA, and TEA.

Thermodynamic models for determination of 3-chloro-N-phenylphthalimide solubility in binary solvent mixtures of (acetone, ethyl acetate or 1,4-dioxane + methanol)

International Nuclear Information System (INIS)

Xie, Yong; Shi, Hongwei; Du, Cunbin; Cong, Yang; Wang, Jian; Zhao, Hongkun

2016-01-01

Highlights: • Solubility of 3-chloro-N-phenylphthalimide in binary mixed solvents were determined. • Solubility data were correlated and calculated by five models. • The standard molar enthalpy for the dissolution processes were calculated. - Abstract: The solubility of 3-chloro-N-phenylphthalimide in binary mixed solvents of (acetone + methanol, ethyl acetate + methanol and 1,4-dioxane + methanol) were determined experimentally by using the isothermal dissolution equilibrium method within the temperature range from (288.15 to 323.15) K under atmosphere pressure. For the binary systems of (acetone + methanol) and (1,4-dioxane + methanol), the solubility of 3-chloro-N-phenylphthalimide increased with increasing temperature and mass fraction of acetone or 1,4-dioxane; and for the (ethyl acetate + methanol) system, at a given composition of ethyl acetate, the solubility of 3-chloro-N-phenylphthalimide increased with an increase in temperature; nevertheless at the same temperature, they increased at first and then decreased with increasing mass fraction of 1,4-dioxane. At the same temperature and mass fraction of acetone, ethyl acetate or 1,4-dioxane, the solubility of 3-chloro-N-phenylphthalimide was greater in (1,4-dioxane + methanol) than in the other two mixed solvents. The solubility values were correlated by employing the Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, Apelblat–Jouyban–Acree model, Ma model, and Sun model. On the whole, the Ma model and Sun model were proven to provide good representation of the experimental solubility results. Furthermore, the dissolution enthalpies of the dissolution process were calculated. The dissolution process of 3-chloro-N-phenylphthalimide in these mixed solvents is endothermic. The experimental solubility and the models in this study could be helpful in purifying 3-chloro-N-phenylphthalimide.

Solvent extraction of lanthanide ions with 1-Phenyl-3-Methyl-4-Benzoyl-Pyrazolone-5 (HPMBP), 2. Extraction of Erbium(III), Ytterbium(III) and Lutetium(III) by HPMBP from aqueous-methanol solutions

International Nuclear Information System (INIS)

Czakis-Sulikowska, D.M.; Kuznik, B.; Malinowska, A.

1990-01-01

The solvent extraction of lanthanides(III)(Ln = Er, Yb, Lu) by 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HL) in carbon tetrachloride from aqueous-methanol phase was investigated. The equilibrium constants for the extraction from aqueous-50 % (ν/ν) methanol phase (K ex ), two-phase stability constants of the complexes LnL 3 (β 3 * ) and stability constants of complexes LnL 2+ , LnL 2 + , LnL 3 (β n )(Ln = Yb, Lu) were calculated. It was confirmed that the addition of methanol to the aqueous phase causes a synergistic effect. The influence of methanol on the dissociation constant of HPMBP (K a ) and the distribution constant of HPMBP (p HL ) between carbon tetrachloride and water-methanol solutions was investigated. (Authors)

NMR and Electrochemical Investigation of the Transport Properties of Methanol and Water in Nafion and Clay-Nanocomposites Membranes for DMFCs

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Vincenzo Baglio

2012-06-01

Full Text Available Water and methanol transport behavior, solvents adsorption and electrochemical properties of filler-free Nafion and nanocomposites based on two smectite clays, were investigated using impedance spectroscopy, DMFC tests and NMR methods, including spin-lattice relaxation and pulsed-gradient spin-echo (PGSE diffusion under variable temperature conditions. Synthetic (Laponite and natural (Swy-2 smectite clays, with different structural and physical parameters, were incorporated into the Nafion for the creation of exfoliated nanocomposites. Transport mechanism of water and methanol appears to be influenced from the dimensions of the dispersed platelike silicate layers as well as from their cation exchange capacity (CEC. The details of the NMR results and the effect of the methanol solution concentration are discussed. Clays particles, and in particular Swy-2, demonstrate to be a potential physical barrier for methanol cross-over, reducing the methanol diffusion with an evident blocking effect yet nevertheless ensuring a high water mobility up to 130 °C and for several hours, proving the exceptional water retention property of these materials and their possible use in the DMFCs applications. Electrochemical behavior is investigated by cell resistance and polarization measurements. From these analyses it is derived that the addition of clay materials to recast Nafion decreases the ohmic losses at high temperatures extending in this way the operating range of a direct methanol fuel cell.

Determination and correlation of solubility and solution thermodynamics of oxiracetam in three (alcohol + water) binary solvents

International Nuclear Information System (INIS)

Li, Kangli; Du, Shichao; Wu, Songgu; Cai, Dongchen; Wang, Jinxu; Zhang, Dejiang; Zhao, Kaifei; Yang, Peng; Yu, Bo; Guo, Baisong; Li, Daixi; Gong, Junbo

2016-01-01

Highlights: • The solubility of racemic oxiracetam in three binary solvents were determined. • The experimental solubility of racemic oxiracetam were correlated by four models. • The dissolution thermodynamic properties of racemic oxiracetam were calculated. - Abstract: In this paper, we proposed a static analysis method to experimentally determine the (solid + liquid) equilibrium of racemic oxiracetam in (methanol + water), (ethanol + water) and (isopropanol + water) binary solvents with alcohol mole fraction ranging from 0.30 to 0.90 at atmosphere pressure (p = 0.1 MPa). For the experiments, the temperatures range from (283.15 to 308.15) K. The results showed that the solubility of oxiracetam increased with the increasing temperature, while decreased with the increasing organic solvent fraction in all three tested binary solvent systems. The modified Apelblat model, the CNIBS/Redlich–Kister model, the combined version of Jouyban–Acree model and the NRTL model were employed to correlate the measured solubility values, respectively. Additionally, some of the thermodynamic properties which can help to evaluate its dissolution behavior were obtained based on the NRTL model.

Effect of alkanolammonium formates ionic liquids on vapour liquid equilibria of binary systems containing water, methanol, and ethanol

International Nuclear Information System (INIS)

Li Xuemei; Shen Chong; Li Chunxi

2012-01-01

Highlights ► Vapour pressures for six ternary systems containing an IL were measured. ► Components studied were water, ethanol, methanol, and alkanolammonium formates. ► The isobaric VLE were predicted using the fitted binary NRTL parameters. ► The ILs studied can generate a promising salt effect on VLE of azeotrope. ► [HMEA][HCOO] might be used as a potential entrainer in extractive distillation. - Abstract: Vapour pressures were measured using a quasi-static ebulliometer for the pseudo-binary mixtures of (water + ethanol), (water + methanol), and (methanol + ethanol) containing an alkanolammonium-based ionic liquid (IL), namely, mono-ethanolammonium formate ([HMEA][HCOO]) and di-ethanolammonium formate ([HDEA][HCOO]), respectively, with fixed IL mass fraction of 0.30 and over the temperature ranges of (292.12 to 371.13) K. The vapour pressures of the IL-containing ternary systems were favourably correlated using the NRTL model with an overall average absolute relative deviation (AARD) of 0.0082. Further, the salt effects of [HMEA][HCOO] and [HDEA][HCOO] on isobaric vapour liquid equilibria (VLE) of azeotrope and close boiling mixture, especially for the mixtures of (water + ethanol) and (methanol + ethanol), were investigated and compared with other ILs in terms of the x′–y phase diagrams predicted with the binary NRTL parameters. It is demonstrated that the relative volatilities of ethanol to water and ethanol to methanol are enhanced, and [HMEA][HCOO] might be used as a promising entrainer for the efficient separation of ethanol aqueous solution by special rectification.

Anti-solvent co-crystallization of carbamazepine and saccharin.

Science.gov (United States)

Wang, In-Chun; Lee, Min-Jeong; Sim, Sang-Jun; Kim, Woo-Sik; Chun, Nan-Hee; Choi, Guang J

2013-06-25

The co-crystal approach has been investigated extensively over the past decade as one of the most promising methods to enhance the dissolution properties of insoluble drug substances. Co-crystal powders are typically produced by mechanical grinding (neat or wet) or a solution method (evaporation or cooling). In this study, high-purity carbamazepine-saccharin (CBZ-SAC) co-crystals were manufactured by a novel method, anti-solvent addition. Among various solvents, methanol was found to perform well with water as the anti-solvent for the co-crystallization of CBZ and SAC. When water was added to the methanol solution of CBZ and SAC at room temperature under agitation, nucleation of CBZ-SAC co-crystals occurred within 2-3 min. Co-crystallization was complete after 30 min, giving a solid yield as high as 84.5% on a CBZ basis. The effects of initial concentrations, focusing on the SAC/CBZ ratio, were examined to establish optimal conditions. The whole anti-solvent co-crystallization process was monitored at-line via ATR-FTIR analysis of regularly sampled solutions. The nucleation and crystal growth of CBZ-SAC co-crystals were detected by a significant increase in absorption in the range of 2400-2260 cm(-1), associated with the formation of hydrogen bonds between the carbonyl group in CBZ and the N-H of SAC. When CBZ hydrates were formed as impurities during anti-solvent co-crystallization, the hydrogen bonding between methanol and water was reduced greatly, primarily due to the incorporation of water molecules into the CBZ crystal lattice. In conclusion, an anti-solvent approach can be used to produce highly pure CBZ-SAC co-crystal powders with a high solid yield. Copyright © 2013 Elsevier B.V. All rights reserved.

A luminescent metal-organic framework for sensing methanol in ethanol solution.

Science.gov (United States)

Jin, Zhao; He, Hongming; Zhao, Huanyu; Borjigin, Tsolmon; Sun, Fuxing; Zhang, Daming; Zhu, Guangshan

2013-10-07

A new luminescent Zn-MOF has been synthesized under hydrothermal condition using a semi-rigid ligand H3pcoip (4-(2-carboxyphenoxy)isophthalic acid) is reported. The luminescence properties of 1 in methanol, ethanol, and water have been investigated. Interestingly, compound 1 has a unique response to methanol compared to ethanol and water. Moreover, 1 displays a turn-on switching property triggered by methanol solvent molecules and a high sensitivity towards methanol concentration as low as 2 × 10(-7) (V(MeOH)/V(total)) in ethanol solution. The results indicate that the Zn-MOF has potential application as a sensor for detecting methanol in ethanol solution with excellent selectivity and high sensitivity.

Determination of mangiferin solubility in solvents used in the biopharmaceutical industry

Directory of Open Access Journals (Sweden)

Jhoany Acosta

2016-04-01

Full Text Available Context: Pharmacological properties and studies of methods of extraction of mangiferin have been reported, but there are not studies related to the solubility of mangiferin in the solvents used in the pharmaceutical industry. Aims: Study the solubility of mangiferin in different solvents used in the pharmaceutical industry. Methods: The mangiferin used had a purity of 97.3% determined by High-Performance Liquid Chromatographic (HPLC, and solubility measurements were made in ethanol, methanol, water, acetone, diethyl ether, and hexane at 5, 15, 30, 40, 50 and 600C of temperature. The mangiferin concentrations were determined by ultraviolet spectrometry at 254 nm. The experimental solubility data were correlated with the Van´t Hoff equation and the dissolution heat determined. Results: The solubility of mangiferin in pure solvents decreases with increasing of temperature and in the following order: ethanol>methanol>water>diethyl ether>acetone>n hexane. Conclusions: This results indicated that mangiferin is slightly soluble in ethanol, sparingly soluble in methanol and water and practically insoluble in diethyl ether, acetone, and n-hexane.

Update of the water chemistry effect on the flow-accelerated corrosion rate of carbon steel: influence of hydrazine, boric acid, ammonia, morpholine and ethanolamine

International Nuclear Information System (INIS)

Pavageau, E.-M.; De Bouvier, O.; Trevin, S.; Bretelle, J.-L.; Dejoux, L.

2007-01-01

The influence of the water chemistry on Flow-Accelerated Corrosion (FAC) affecting carbon steel components has been studied for many years and is relatively well known and taken into account by the models. Nonetheless, experimental studies were conducted in the last few years at EDF on the CIROCO loop in order to check the influence of the water chemistry parameters (hydrazine, boric acid, ammonia, morpholine and ethanolamine) on the FAC rate of carbon steel in one phase flow conditions. The hydrazine impact on the FAC rate was shown to be minor in EDF's chemistry recommendation range, compared to other parameters' effects such as the pH effect. The presence of boric acid in the nominal secondary circuit conditions was negligible. Finally, as expected, the nature of the chemical conditioning (ammonia, morpholine or ethanolamine) did not modify the FAC rate, the influencing chemical variable being the at-temperature pH in one-phase flow conditions. (author)

Spin-crossover in [Fe(3-bpp)2][BF4]2 in different solvents--a dramatic stabilisation of the low-spin state in water.

Science.gov (United States)

Barrett, Simon A; Kilner, Colin A; Halcrow, Malcolm A

2011-12-07

The temperature of spin-crossover in [Fe(3-bpp)(2)][BF(4)](2) (3-bpp = 2,6-di{pyrazol-3-yl}pyridine) tends to increase in associating solvents. In particular, T(½) shifts to 60-70 K higher temperature in water compared to organic solvents.

Hydration of ammonia, methylamine, and methanol in amorphous solid water

Science.gov (United States)

Souda, Ryutaro

2016-02-01

Interactions of polar protic molecules with amorphous solid water (ASW) have been investigated using temperature-programmed desorption and time-of-flight secondary ion mass spectrometry. The ammonia and methylamine are incorporated into the interior of porous ASW films. They are caged by water molecules and are released during water crystallization. In contrast, the methanol-water interaction is not influenced by pores of ASW. The methanol additives tend to survive water crystallization and are released during ASW film evaporation. The hydration of n-hexane in ASW is influenced significantly by methanol additives because n-hexane is accommodated in a methanol-induced hydration shell.

Experimental measurement and modelling of solubility of inosine-5′-monophosphate disodium in pure and mixed solvents

International Nuclear Information System (INIS)

Zou, Fengxia; Zhuang, Wei; Wu, Jinglan; Zhou, Jingwei; Liu, Qiyan; Chen, Yong; Xie, Jingjing; Zhu, Chenjie; Guo, Ting; Ying, Hanjie

2014-01-01

Graphical abstract: - Highlights: • Solubility of 5′-IMPNa 2 in various solvents was studied for the first time. • The solubility could be ranked as follows: water > methanol > ethanol > acetone. • Modified Apelblat equation gave the best correlating results. • Mixing Gibbs free energies, enthalpies, and entropies were predicted. • Solubility data and equations can optimise the crystallization conditions. - Abstract: The solubility of biological chemicals in solvents provide important fundamental data and is generally considered as an essential factor in the design of crystallization processes. The equilibrium solubility data of inosine-5′-monophosphate disodium (5′-IMPNa 2 ) in water, methanol, ethanol, acetone, as well as in the solvent mixtures (methanol + water, ethanol + water, acetone + water), were measured by an isothermal method at temperatures ranging from (293.15 to 313.15) K. The measured data in pure and mixed solvents were then modelled using the modified Apelblat equation, van’t Hoff equation, λh equation, ideal model and the Wilson model. The modified Apelblat equation showed the best modelling results, and it was therefore used to predict the mixing Gibbs free energies, enthalpies, and entropies of 5′-IMPNa 2 in pure and binary solvents. The positive values of the calculated partial molar Gibbs free energies indicated the variations in the solubility trends of 5′-IMPNa 2 . Water and ethanol (in the binary mixture with water) were found to be the most effective solvent and anti-solvent, respectively

Separation of xylose oligomers using centrifugal partition chromatography with a butanol-methanol-water system.

Science.gov (United States)

Lau, Ching-Shuan; Clausen, Edgar C; Lay, Jackson O; Gidden, Jennifer; Carrier, Danielle Julie

2013-01-01

Xylose oligomers are the intermediate products of xylan depolymerization into xylose monomers. An understanding of xylan depolymerization kinetics is important to improve the conversion of xylan into monomeric xylose and to minimize the formation of inhibitory products, thereby reducing ethanol production costs. The study of xylan depolymerization requires copious amount of xylose oligomers, which are expensive if acquired commercially. Our approach consisted of producing in-house oligomer material. To this end, birchwood xylan was used as the starting material and hydrolyzed in hot water at 200 °C for 60 min with a 4 % solids loading. The mixture of xylose oligomers was subsequently fractionated by a centrifugal partition chromatography (CPC) with a solvent system of butanol:methanol:water in a 5:1:4 volumetric ratio. Operating in an ascending mode, the butanol-rich upper phase (the mobile phase) eluted xylose oligomers from the water-rich stationary phase at a 4.89 mL/min flow rate for a total fractionation time of 300 min. The elution of xylose oligomers occurred between 110 and 280 min. The yields and purities of xylobiose (DP 2), xylotriose (DP 3), xylotetraose (DP 4), and xylopentaose (DP 5) were 21, 10, 14, and 15 mg/g xylan and 95, 90, 89, and 68 %, respectively. The purities of xylose oligomers from this solvent system were higher than those reported previously using tetrahydrofuran:dimethyl sulfoxide:water in a 6:1:3 volumetric ratio. Moreover, the butanol-based solvent system improved overall procedures by facilitating the evaporation of the solvents from the CPC fractions, rendering the purification process more efficient.

Evaporation phase change processes of water/methanol mixtures on superhydrophobic nanostructured surfaces

Science.gov (United States)

Chiang, Cheng-Kun; Lu, Yen-Wen

2011-07-01

Evaporation phenomena are a critical and frequently seen phase change process in many heat transfer applications. In this paper, we study the evaporation process of a sessile droplet on two topologically different surfaces, including smooth and nanostructured surfaces. The nanostructured surface has an array of high-aspect-ratio nanowires (height/diameter ~ 125) and is implemented by using a simple template-based nanofabrication method. It possesses superhydrophobicity (>140°) and low contact angle hysteresis (1.2-2.1°), allowing the liquid droplets to remain in the 'fakir' state throughout the evaporation processes. Sessile droplets of deionized (DI) water and water/methanol binary mixture test liquids with their contact angles and base diameters are monitored. The results show that the nanostructures play a critical role in the droplet dynamics during evaporation.

Evaporation phase change processes of water/methanol mixtures on superhydrophobic nanostructured surfaces

International Nuclear Information System (INIS)

Chiang, Cheng-Kun; Lu, Yen-Wen

2011-01-01

Evaporation phenomena are a critical and frequently seen phase change process in many heat transfer applications. In this paper, we study the evaporation process of a sessile droplet on two topologically different surfaces, including smooth and nanostructured surfaces. The nanostructured surface has an array of high-aspect-ratio nanowires (height/diameter ∼ 125) and is implemented by using a simple template-based nanofabrication method. It possesses superhydrophobicity (>140°) and low contact angle hysteresis (1.2–2.1°), allowing the liquid droplets to remain in the 'fakir' state throughout the evaporation processes. Sessile droplets of deionized (DI) water and water/methanol binary mixture test liquids with their contact angles and base diameters are monitored. The results show that the nanostructures play a critical role in the droplet dynamics during evaporation

Glass transition and intermixing of amorphous water and methanol

International Nuclear Information System (INIS)

Souda, Ryutaro

2004-01-01

The diffusion of molecules in amorphous water and methanol films has been investigated on the basis of time-of-flight secondary ion mass spectrometry as a function of temperature. The glass-liquid transition of the amorphous water film occurs at 130-145 K as confirmed from the surface segregation of embedded methanol molecules. The morphology of the pure amorphous water film changes drastically at 160 K as a consequence of dewetting induced by the surface tension and the strongly decreased viscosity of the film. The morphology of the amorphous methanol film changes at 115 K following the self-diffusion onset at 80 K. The binary films of water and heavy methanol are intermixed completely at 136 K as evidenced by the occurrence of the H/D exchange

Thermodynamic functions of hydrogen bonding of amines in methanol derived from solution calorimetry data and headspace analysis

Energy Technology Data Exchange (ETDEWEB)

Zaitseva, Ksenia V., E-mail: zaitseva.ksenia@gmail.com [Chemical Institute, Kazan (Volga Region) Federal University, Kremlevskaya 18, Kazan 420008 (Russian Federation); Varfolomeev, Mikhail A., E-mail: vma.ksu@gmail.com [Chemical Institute, Kazan (Volga Region) Federal University, Kremlevskaya 18, Kazan 420008 (Russian Federation); Solomonov, Boris N., E-mail: boris.solomonov@ksu.ru [Chemical Institute, Kazan (Volga Region) Federal University, Kremlevskaya 18, Kazan 420008 (Russian Federation)

2012-05-10

Highlights: Black-Right-Pointing-Pointer Solution enthalpies and activity coefficients of amines in methanol were measured. Black-Right-Pointing-Pointer Thermodynamic functions of H-bonding of amines with methanol were determined. Black-Right-Pointing-Pointer Specific interaction entropy of amines in methanol can be about zero or positive. Black-Right-Pointing-Pointer Cooperativity of H-bonds in methanol media is smaller than in water solutions. Black-Right-Pointing-Pointer A new view on analysis of specific interaction of solute with methanol is presented. - Abstract: Reactivity and equilibrium properties of organic molecules in self-associated liquids greatly depend on the hydrogen bonding with solvent. This work contains comprehensive thermodynamic analysis of hydrogen bonding of aliphatic and aromatic amines in self-associated solvent methanol. Enthalpies of solution at infinite dilution and limiting activity coefficients for the studied systems were measured experimentally. Enthalpies and Gibbs energies of hydrogen bonding of amines with neat methanol were determined. These values were found to be decreased compared with hydrogen bond energy in equimolar complexes 'methanol-amine' determined in inert solvent or base media. A linear dependence between enthalpies and Gibbs energies of hydrogen bonding of amines with neat methanol was observed. It was firstly revealed that the entropy of specific interactions of amines with neat methanol can be about zero or positive. Disruption of solvent-solvent hydrogen bonds can be regarded as the most important step during dissolution of amine in methanol. It was found that the cooperative effect influences on the Gibbs energies of hydrogen bonding of amines in methanol, but in a lesser extent than in aqueous solutions. The new results show that the hydrogen bonding process in the self-associated solvents differs significantly from equimolar complexation in aprotic media.

Modification of molybdenum disulfide in methanol solvent for hydrogen evolution reaction

Science.gov (United States)

Niyitanga, Theophile; Jeong, Hae Kyung

2018-05-01

Molybdenum disulfide is a promising catalyst to replace the expensive platinum as an electrocatalyst but needs to be modified to present excellent electrocatalytic properties. Herein, we successfully modify molybdenum disulfide in methanol solvent for hydrogen evolution reaction by using a simple hydrothermal method. Overpotential reduced to -0.6 V from -1.5 V, and energy band gap decreased from 1.73 eV to 1.58 eV after the modification. The modified molybdenum disulfide also demonstrated lower resistance (42 Ω) at high frequency (1000 kHz) compared with that (240 Ω) of the precursor, showing that conductivity of the modified molybdenum disulfide has improved.

Thermodynamics of ionic migration of simple and complex rare earth salts in mixed alcohol solvents

International Nuclear Information System (INIS)

Gorodyskij, A.V.; Fialkov, Yu.Ya.; Chernyj, D.B.

1982-01-01

The influence of the composition of double mixed solvents (water-methanol and methanol-propanol) on thermodynamic characteristics of electrolytic dissociation process-enthalpy and entropy, dissociation constants of chlorides and diphenanthroline chlorides of lanthanum, neodymium, europium and dysprosium, is analyzed. It is shown that when passing from water to methanol, that is, with decrease of dielectric permeability, the endothermicity of electrolytic dissociation process increases

Thermodynamics of ionic migration of simple and complex rare earth salts in mixed alcohol solvents

Energy Technology Data Exchange (ETDEWEB)

Gorodyskij, A.V.; Fialkov, Yu.Ya.; Chernyj, D.B. (AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii; Kievskij Politekhnicheskij Inst. (Ukrainian SSR))

1982-04-01

The influence of the composition of double mixed solvents (water-methanol and methanol-propanol) on thermodynamic characteristics of electrolytic dissociation process-enthalpy and entropy, dissociation constants of chlorides and diphenanthroline chlorides of lanthanum, neodymium, europium and dysprosium, is analyzed. It is shown that when passing from water to methanol, that is, with decrease of dielectric permeability, the endothermicity of electrolytic dissociation process increases.

Acidities of Water and Methanol in Aqueous Solution and DMSO

Science.gov (United States)

Gao, Daqing

2009-01-01

The relative acidities of water and methanol have been a nagging issue. In gas phase, methanol is more acidic than water by 36.0 kJ/mol; however, in aqueous solution, the acidities of methanol and water are almost identical. The acidity of an acid in solution is determined by both the intrinsic gas-phase ionization Gibbs energy and the solvent…

Ethanolamine properties and use for feedwater pH control: A pressurized water reactor case study

International Nuclear Information System (INIS)

Keeling, D.L.; Polidoroff, C.T.; Cortese, S.; Cushner, M.C.

1995-01-01

Ethanolamine (ETA) as a feedwater pH control additive has been recently used to minimize corrosion of secondary water components in the nuclear power industry pressurized water reactors (PWRs). The use of ETA is compared with ammonia. Relative volatility effects on various parts of the system are analyzed and chemistry changes are presented. Materials of construction and the use of existing plant equipment for ETA service are discussed. Properties of ETA as well as safety, storage and handling issues are compared with ammonia. Health d aquatic toxicity are reviewed. warnings, safety, handling guidelines, biodegradability an Diablo Canyon Power Plant used ammonia for pH control from 1985 until a change over to ETA in 1993/1994. Full flow condensate polishers that are required to protect the plant from saltwater cooling incursions limit the amount of pH additive. Iron levels in the secondary water systems are compared before and after changing to ETA and replacement of corrosion-susceptible piping. Iron reduction benefits are assessed along with other effects on the feedwater nozzles, low pressure turbine, polisher resin capacity and polisher regeneration system

Controlling Actinide Hydration in Mixed Solvent Systems: Towards Tunable Solvent Systems to Close the Fuel Cycle

International Nuclear Information System (INIS)

Clark, Sue B.

2016-01-01

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.

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.

Lithium recovery from shale gas produced water using solvent extraction

International Nuclear Information System (INIS)

Jang, Eunyoung; Jang, Yunjai; Chung, Eunhyea

2017-01-01

Shale gas produced water is hypersaline wastewater generated after hydraulic fracturing. Since the produced water is a mixture of shale formation water and fracturing fluid, it contains various organic and inorganic components, including lithium, a useful resource for such industries as automobile and electronics. The produced water in the Marcellus shale area contains about 95 mg/L lithium on average. This study suggests a two-stage solvent extraction technique for lithium recovery from shale gas produced water, and determines the extraction mechanism of ions in each stage. All experiments were conducted using synthetic shale gas produced water. In the first-stage, which was designed for the removal of divalent cations, more than 94.4% of Ca"2"+, Mg"2"+, Sr"2"+, and Ba"2"+ ions were removed by using 1.0 M di-(2-ethylhexyl) phosphoric acid (D2EHPA) as an extractant. In the second-stage, for lithium recovery, we could obtain a lithium extraction efficiency of 41.2% by using 1.5 M D2EHPA and 0.3 M tributyl phosphate (TBP). Lithium loss in the first-stage was 25.1%, and therefore, the total amount of lithium recovered at the end of the two-step extraction procedure was 30.8%. Through this study, lithium, one of the useful mineral resources, could be selectively recovered from the shale gas produced water and it would also reduce the wastewater treatment cost during the development of shale gas. - Highlights: • Lithium was extracted from shale gas produced water using an organic solvent. • Two-stage solvent extraction technique was applied. • Divalent cations were removed in the first stage by D2EHPA. • Lithium was selectively recovered in the second stage by using TBP with D2EHPA.

Calorimetric determination of enthalpy changes for the proton ionization of 3-[N-morpholino]propanesulfonic acid (MOPS), 4-[N-morpholino]butanesulfonic acid (MOBS) and 3-[N-morpholino]-2-hydroxypropanesulfonic acid (MOPSO) in water-methanol mixtures

International Nuclear Information System (INIS)

Jumean, F.H.; Abdo, N.M.; Khamis, M.I.

2011-01-01

Highlights: → Two-stage proton ionizations for three N-substituted sulfonic acid derivatives of morpholine. → ΔH 1 and ΔH 2 in x methanol = 0-0.360 measured for MOPS, MOBS and MOPSO. → In water, ΔH 1 = ±1.2 kJ mol -1 , ΔH 2 range 20.7-26.3 kJ mol -1 . → Methanol addition had little effect on ΔH 1 but ΔH 2 rose steadily to 32.2 kJ mol -1 . → Results related to molecular and solvent parameters. - Abstract: Proton ionization enthalpies for three structurally related biological buffers, each with two ionizable protons, were determined using solution calorimetry. These buffers are 3-[N-morpholino]propanesulfonic acid (MOPS), 4-[N-morpholino]butanesulfonic acid (MOBS) and 3-[N-morpholino]-2-hydroxypropanesulfonic acid (MOPSO). Enthalpies were obtained in water-methanol mixtures with methanol mole fraction (X m ) from 0 to 0.360. The first ionization enthalpy (ΔH 1 ) of all buffers was small (±1.2 kJ mol -1 ) at all solvent compositions. The second ionization enthalpy (ΔH 2 ) increased steadily with X m , rising from 20.7 to 25.6 kJ mol -1 for MOPS, 26.3-31.0 kJ mol -1 for MOBS and 23.5-32.2 kJ mol -1 for MOPSO. The results were compared to those for related biological buffers. The observed variations were interpreted in terms of solvent-solvent and solvent-solute interactions.

Ethanolamine experience at Koeberg nuclear power station, South Africa

International Nuclear Information System (INIS)

Galt, K.J.; Caris, N.B.

2002-01-01

Following testing of ethanolamine as an alternative to ammonia on Unit 2 in 1997, Unit 1 of the Koeberg Nuclear Power Station was converted to ethanolamine in 1998. The Unit has now operated for just over one and a half cycle on ETA. The decision to change to ETA was made to achieve further reductions in feedwater iron transport. Koeberg has always operated ammonia/hydrazine AVT control and ran the feedwater pH at 9.6-9.7 before the changeover. The original pH levels were increased in response to concerns over flow-accelerated corrosion. A by product of reducing the FAC rates is a reduction in iron transport. Although nominally all-ferrous, there are a number of small copper-containing components and the Koeberg Engineering Department would not countenance a further increase in ammonia concentrations in case of copper transport to the SGs. This led to ethanolamine being selected as an alternative to ammonia. The Koeberg condensate polishing plant has been modified, largely to accommodate ETA operation, but is not currently operable in the modified configuration. It is therefore on standby while ETA is implemented. The SG blowdown demineralizers have begun to be operated past ammonia/ETA break, but optimisation is largely dependent on CPP availability in the modified configuration. This paper documents the Koeberg experience to date of operation under an ethanolamine-AVT regime. As one of the few plants outside of the USA to have changed to ethanolamine, it is hoped we can make a valuable contribution for other non-US plants considering such a move. (authors)

Linear correlation of interfacial tension at water-solvent interface, solubility of water in organic solvents, and SE* scale parameters

International Nuclear Information System (INIS)

Mezhov, E.A.; Khananashvili, N.L.; Shmidt, V.S.

1988-01-01

A linear correlation has been established between the solubility of water in water-immiscible organic solvents and the interfacial tension at the water-solvent interface on the one hand and the parameters of the SE* and π* scales for these solvents on the other hand. This allows us, using the known tabulated SE* or π* parameters for each solvent, to predict the values of the interfacial tension and the solubility of water for the corresponding systems. We have shown that the SE* scale allows us to predict these values more accurately than other known solvent scales, since in contrast to other scales it characterizes solvents found in equilibrium with water

Thermodynamic functions of hydrogen bonding of amines in methanol derived from solution calorimetry data and headspace analysis

International Nuclear Information System (INIS)

Zaitseva, Ksenia V.; Varfolomeev, Mikhail A.; Solomonov, Boris N.

2012-01-01

Highlights: ► Solution enthalpies and activity coefficients of amines in methanol were measured. ► Thermodynamic functions of H-bonding of amines with methanol were determined. ► Specific interaction entropy of amines in methanol can be about zero or positive. ► Cooperativity of H-bonds in methanol media is smaller than in water solutions. ► A new view on analysis of specific interaction of solute with methanol is presented. - Abstract: Reactivity and equilibrium properties of organic molecules in self-associated liquids greatly depend on the hydrogen bonding with solvent. This work contains comprehensive thermodynamic analysis of hydrogen bonding of aliphatic and aromatic amines in self-associated solvent methanol. Enthalpies of solution at infinite dilution and limiting activity coefficients for the studied systems were measured experimentally. Enthalpies and Gibbs energies of hydrogen bonding of amines with neat methanol were determined. These values were found to be decreased compared with hydrogen bond energy in equimolar complexes “methanol–amine” determined in inert solvent or base media. A linear dependence between enthalpies and Gibbs energies of hydrogen bonding of amines with neat methanol was observed. It was firstly revealed that the entropy of specific interactions of amines with neat methanol can be about zero or positive. Disruption of solvent–solvent hydrogen bonds can be regarded as the most important step during dissolution of amine in methanol. It was found that the cooperative effect influences on the Gibbs energies of hydrogen bonding of amines in methanol, but in a lesser extent than in aqueous solutions. The new results show that the hydrogen bonding process in the self-associated solvents differs significantly from equimolar complexation in aprotic media.

Rapid determination of benzene derivatives in water samples by trace volume solvent DLLME prior to GC-FID

Energy Technology Data Exchange (ETDEWEB)

Diao, Chun Peng; Wei, Chao Hai; Feng, Chun Hua [South China Univ. of Technology, Guangzhou Higher Education Mega Center (China). College of Environmental Science and Engineering; Guangdong Regular Higher Education Institutions, Guangzhou (China). Key Lab. of Environmental Protection and Eco-Remediation

2012-05-15

An inexpensive, simple and environmentally friendly method based on dispersive liquid liquid microextraction (DLLME) for rapid determination of benzene derivatives in water samples was proposed. A significant improvement of DLLME procedure was achieved. Trace volume ethyl acetate (60 {mu}L) was exploited as dispersion solvent instead of common ones such as methanol and acetone, the volume of which was more than 0.5 mL, and the organic solvent required in DLLME was reduced to a great extent. Only 83-{mu}L organic solvent was consumed in the whole analytic process and the preconcentration procedure was less than 10 min. The advantageous approach coupled with gas chromatograph-flame ionization detector was proposed for the rapid determination of benzene, toluene, ethylbenzene and xylene isomers in water samples. Results showed that the proposed approach was an efficient method for rapid determination of benzene derivatives in aqueous samples. (orig.)

Stable Isotope-Assisted Evaluation of Different Extraction Solvents for Untargeted Metabolomics of Plants

Directory of Open Access Journals (Sweden)

Maria Doppler

2016-06-01

Full Text Available The evaluation of extraction protocols for untargeted metabolomics approaches is still difficult. We have applied a novel stable isotope-assisted workflow for untargeted LC-HRMS-based plant metabolomics , which allows for the first time every detected feature to be considered for method evaluation. The efficiency and complementarity of commonly used extraction solvents, namely 1 + 3 (v/v mixtures of water and selected organic solvents (methanol, acetonitrile or methanol/acetonitrile 1 + 1 (v/v, with and without the addition of 0.1% (v/v formic acid were compared. Four different wheat organs were sampled, extracted and analysed by LC-HRMS. Data evaluation was performed with the in-house-developed MetExtract II software and R. With all tested solvents a total of 871 metabolites were extracted in ear, 785 in stem, 733 in leaf and 517 in root samples, respectively. Between 48% (stem and 57% (ear of the metabolites detected in a particular organ were found with all extraction mixtures, and 127 of 996 metabolites were consistently shared between all extraction agent/organ combinations. In aqueous methanol, acidification with formic acid led to pronounced pH dependency regarding the precision of metabolite abundance and the number of detectable metabolites, whereas extracts of acetonitrile-containing mixtures were less affected. Moreover, methanol and acetonitrile have been found to be complementary with respect to extraction efficiency. Interestingly, the beneficial properties of both solvents can be combined by the use of a water-methanol-acetonitrile mixture for global metabolite extraction instead of aqueous methanol or aqueous acetonitrile alone.

Effect of solvent and temperature on solution-crystallized terfenadine

International Nuclear Information System (INIS)

Leitao, M. Luisa P.; Canotilho, Joao; Ferreira, Simone C.R.; Sousa, Adriano T.; Simoes Redinha, J.

2004-01-01

The aim of this work was to understand the crystallization process of terfenadine in solution. Cooling of saturated solutions prepared at 50 deg. C at different temperatures, evaporating the solvent from nearly saturated solutions at a certain temperature, and exposing ethanol solutions of terfenadine to water vapour atmosphere were the techniques used for obtaining terfenadine specimens. The characterization of these specimens was carried out by thermal microscopy, differential thermal analysis, thermogravimetry and powder X-ray diffraction. Crystalline phases, amorphous solids, and solvates were identified. For the solvents used in the present study, the crystallinity degree of terfenadine decreases from ethanol-water to ethanol and from this to methanol. Decreasing the temperature promotes the formation of amorphous solid material; at low temperatures, methanol and ethanol solvates are also formed. Desolvation, following the terfenadine aggregation process in solution accounts for the different behaviour found for the solvents and for the effect of temperature on the structure. The role of the solvent as structure-mediator is explained on the grounds of the values previously published for the enthalpy of solution of terfenadine in the solvents under study

Solvent Extraction of Rare Earths by Di-2 Ethylhexyl Phosphoric Acid

International Nuclear Information System (INIS)

Srinuttrakul, Wannee; Kranlert, Kannika; Kraikaew, Jarunee; Pongpansook, Surasak; Chayavadhanangkur, Chavalek; Kranlert, Kannika

2004-10-01

Solvent extraction has been widely applied for individual rare earth separation because the separation time is rapid and a large quantity of products is obtained. In this work, this technique was utilized to extract mixed rare earths, obtained from monazite digestion process. Di-2-ethylhexyl phosphoric acid (D2EHPA) was used as an extractant. The factors affected the extraction including HNO 3 concentration in mixed rare earth nitrate solution and the amount of D2EHPA were studied. The appropriate concentrations of HNO 3 and D2EHPA were found to be 0.01 and 1.5 M, respectively. From the result of equilibrium curve study, it was observed that heavy rare earths were extracted more efficient than light rare earths. A 6-stage continuous countercurrent solvent extraction was simulated for rare earth extraction. The optimum ratio of solvent to feed solution (S/F) was 2. Because of the high cost of D2EHPA, 1.0 M of D2EHPA was suitable for the rare earth extraction by the continuous countercurrent solvent extraction

A cuboctahedral platinum (Pt79) nanocluster enclosed by well defined facets favours di-sigma adsorption and improves the reaction kinetics for methanol fuel cells.

Science.gov (United States)

Mahata, Arup; Choudhuri, Indrani; Pathak, Biswarup

2015-08-28

The methanol dehydrogenation steps are studied very systematically on the (111) facet of a cuboctahedral platinum (Pt79) nanocluster enclosed by well-defined facets. The various intermediates formed during the methanol decompositions are adsorbed at the edge and bridge site of the facet either vertically (through C- and O-centres) or in parallel. The di-sigma adsorption (in parallel) on the (111) facet of the nanocluster is the most stable structure for most of the intermediates and such binding improves the interaction between the substrate and the nanocluster and thus the catalytic activity. The reaction thermodynamics, activation barrier, and temperature dependent reaction rates are calculated for all the successive methanol dehydrogenation steps to understand the methanol decomposition mechanism, and these values are compared with previous studies to understand the catalytic activity of the nanocluster. We find the catalytic activity of the nanocluster is excellent while comparing with any previous reports and the methanol dehydrogenation thermodynamics and kinetics are best when the intermediates are adsorbed in a di-sigma manner.

Solvent-dependent transformation of aflatoxin B1 in soil.

Science.gov (United States)

Starr, James M; Rushing, Blake R; Selim, Mustafa I

2017-08-01

To date, all studies of aflatoxin B 1 (AFB 1 ) transformation in soil or in purified mineral systems have identified aflatoxins B 2 (AFB 2 ) and G 2 (AFG 2 ) as the primary transformation products. However, identification in these studies was made using thin layer chromatography which has relatively low resolution, and these studies did not identify a viable mechanism by which such transformations would occur. Further, the use of methanol as the solvent delivery vehicle in these studies may have contributed to formation of artifactual transformation products. In this study, we investigated the role of the solvent vehicle in the transformation of AFB 1 in soil. To do this, we spiked soils with AFB 1 dissolved in water (93:7, water/methanol) or methanol and used HPLC-UV and HPLC-MS to identify the transformation products. Contrasting previous published reports, we did not detect AFB 2 or AFG 2 . In an aqueous-soil environment, we identified aflatoxin B 2a (AFB 2a ) as the single major transformation product. We propose that AFB 2a is formed from hydrolysis of AFB 1 with the soil acting as an acid catalyst. Alternatively, when methanol was used, we identified methoxy aflatoxin species likely formed via acid-catalyzed addition of methanol to AFB 1 . These results suggest that where soil moisture is adequate, AFB 1 is hydrolyzed to AFB 2a and that reactive organic solvents should be avoided when replicating natural conditions to study the fate of AFB 1 in soil.

Phase equilibria at low temperature for light hydrocarbons-methanol-water-acid gases mixtures: measurements and modelling; Equilibres de phases a basse temperature de systemes complexes CO{sub 2} - hydrocarbures legers - methanol - eau: mesures et modelisation

Energy Technology Data Exchange (ETDEWEB)

Ruffine, L.

2005-10-15

The need to develop and improve natural gas treatment processes is real. The petroleum industry usually uses separation processes which require phase equilibrium phenomena. Yet, the complexity of the phase equilibria involved results in a lack of data, which in turn limits the development of thermodynamic models. The first part of this work is devoted to experimental investigations for systems containing light hydrocarbons, methanol, water and acid gases. We present a new apparatus that was developed to measure vapor-liquid and vapor-liquid-liquid equilibria. It allowed us to obtain new phase composition data for the methanol-ethane binary system and different mixtures, and also to determine a part of the three phases equilibrium envelope of the same systems. In the second part of this work, we have developed a thermodynamic model based on the CPA equation of state. This choice may be justified by the presence of associating components like methanol, hydrogen sulfide and water in the systems. Such model is necessary for the design of gas treatment plants. Our model provides good results for phase equilibrium calculations for binaries systems without binary interaction parameter in many cases, and describes correctly the vapour-liquid and vapor-liquid-liquid equilibria for complex mixtures. (author)

Fractionation of deuterium and protium between water and methanol

International Nuclear Information System (INIS)

Rolston, J.H.; Gale, K.L.

1984-01-01

The overall deuterium-protium separation factor, α, between hydrogen gas and aqueous methanol mixtures has been measured over the full composition range at temperatures between 25 and 55 0 C. At each temperature α increases smoothly with increasing mole fraction of methanol but the values fall significantly below the straight line joining the separation factors for the methanol-hydrogen and water-hydrogen systems. The equilibrium constant, K 1 (1), for exchange of a deuterium atom tracer between the hydroxyl groups of methanol and liquid water, calculated from the values of α for each solution, is independent of composition within experimental error. The value of K 1 (1) at 25 0 C is 0.54 +/- 0.02, so that deuterium favors the methanol environment rather than water. The dependence of k 1 (1) on absolute temperature, T, is given by the expression 1n K 1 (1) = -0.776 + 52.6/T, which corresponds to a reaction enthalpy of -0.43 kJ mol -1 . 24 references, 2 figures, 2 tables

Basicity comparison for di-substituted 4-nitropyridine derivatives in polar non-aqueous media

International Nuclear Information System (INIS)

Gurzynski, Lukasz; Puszko, Aniela; Chmurzynski, Lech

2007-01-01

Acid dissociation, as well as cationic homoconjugation equilibria have been studied potentiometrically in systems involving four di-substituted 4-nitropyridines and conjugate cationic acids in the polar non-aqueous solvents - aprotic protophobic acetonitrile (AN) and propylene carbonate (PC), the amphiprotic methanol (MeOH), and in the aprotic protophilic dimethyl sulfoxide (DMSO). The influence of solvent effect on the obtained acidity constants has been discussed. The acidity constants (expressed as pK a values) were compared with those previously determined in another polar protophobic aprotic solvent - acetone (AC), and obtained for the unsubstituted pyridine (Py). A comparison of the acid dissociation constants determined in all media studied has proved that the strength of the cationic acids increases on going from acetonitrile through propylene carbonate, acetone, and methanol to dimethyl sulfoxide. Furthermore, the values of acidity constants in the non-aqueous media have shown that in all the solvents studied they change according to the substituent effects. It has been also found that substituted 4-nitropyridine derivatives studied exhibit no tendency towards cationic homoconjugation in acetonitrile, propylene carbonate, and methanol and dimethyl sulfoxide. Moreover, it has been demonstrated that the acid dissociation constants determined by potentiometric titration method in all the solutions investigated correlate well with the calculated energy parameters of the protonation reactions in the gaseous phase

Basicity comparison for di-substituted 4-nitropyridine derivatives in polar non-aqueous media

Energy Technology Data Exchange (ETDEWEB)

Gurzynski, Lukasz [Department of General and Inorganic Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Puszko, Aniela [Department of Organic Chemistry, School of Economics, Wroclaw (Poland); Chmurzynski, Lech [Department of General and Inorganic Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)], E-mail: lech@chemik.chem.univ.gda.pl

2007-12-15

Acid dissociation, as well as cationic homoconjugation equilibria have been studied potentiometrically in systems involving four di-substituted 4-nitropyridines and conjugate cationic acids in the polar non-aqueous solvents - aprotic protophobic acetonitrile (AN) and propylene carbonate (PC), the amphiprotic methanol (MeOH), and in the aprotic protophilic dimethyl sulfoxide (DMSO). The influence of solvent effect on the obtained acidity constants has been discussed. The acidity constants (expressed as pK{sub a} values) were compared with those previously determined in another polar protophobic aprotic solvent - acetone (AC), and obtained for the unsubstituted pyridine (Py). A comparison of the acid dissociation constants determined in all media studied has proved that the strength of the cationic acids increases on going from acetonitrile through propylene carbonate, acetone, and methanol to dimethyl sulfoxide. Furthermore, the values of acidity constants in the non-aqueous media have shown that in all the solvents studied they change according to the substituent effects. It has been also found that substituted 4-nitropyridine derivatives studied exhibit no tendency towards cationic homoconjugation in acetonitrile, propylene carbonate, and methanol and dimethyl sulfoxide. Moreover, it has been demonstrated that the acid dissociation constants determined by potentiometric titration method in all the solutions investigated correlate well with the calculated energy parameters of the protonation reactions in the gaseous phase.

Water quality and MTBE water pollution; Evidenze di presenza di MTBE sulle acque sotterranee di aree a rischio

Energy Technology Data Exchange (ETDEWEB)

Buiatti, M.; Mascini, M.; Monanni, R. [Florence Univ., Florence (Italy). Centro Interdipartimentale Biotecnologie Agrarie Chimiche Industriali; Agati, L.; Bartoli, C.; Bolletti, P.; Cortonesi, B.; Martinelli, L. [Agenzia Regionale per la Protezione dell' Ambiente della Toscana, Florence (Italy); Filipponi, M.; Piangoloni, A. [Nuove Acque SpA,, Arezzo (Italy); Mancini, G. [Autorita' di ambito territoriale ottimale n.4, Arezzo (Italy)

2001-11-01

The research project, here presented, was defined with the aim of evaluating the eventual presence of MTBE and the possible relative impact in water destined to human use; the territorial valence of the project was extended to the competence region n. 4 of the Tuscany water authority (AATO n. 4). University of Florence, ARPAT, AATO n. 4 and Nuove Acque SpA, in this role of manager for the integrated water cycle in the country, have productively contributed to the project. [Italian] La Nuove Acque SpA, soggetto gestore del ciclo idrico integrato, l'Universita' degli Studi di Firenze, l'Agenzia Regionale per la Protezione Ambientale e l'Autorita' di Ambito Territoriale hanno realizzato un progetto di verifica e messa a punto delle metodologie analitiche per il monitoraggio delle eventuali presenze di MTBE nelle acque, con particolare riferimento agli acquiferi sotterranei.

On linear correlation between interfacial tension of water-solvent interface solubility of water in organic solvents and parameters of diluent effect scale

International Nuclear Information System (INIS)

Mezhov, Eh.A.; Khananashvili, N.L.; Shmidt, V.S.

1988-01-01

Presence of linear correlation between water solubility in nonmiscible with it organic solvents, interfacial tension of water-solvent interface, on the one hand, and solvent effect scale parameters and these solvents π* - on the other hand, is established. It allows, using certain tabular parameters of solvent effect or each solvent π*, to predict values of interfacial tension and water solubility for corresponding systems. It is shown, that solvent effect scale allows to predict values more accurately, than other known solvent scales, as it in contrast to other scales characterizes solvents, which are in equilibrium with water

Solvent extraction of thorium(IV) with dibutyldithiophosphoric acid in various organic solvents

International Nuclear Information System (INIS)

Curtui, M.; Haiduc, I.

1994-01-01

The extraction of thorium(IV) from perchlorate solutions with di-n-butyldithiophosphoric acid (HBudtp) in various organic solvents occurs through an ion exchange mechanism. The extracted species in the organic phase is an eight-coordinate complex Th(Budtp) 4 . The higher values of the distribution ratio obtained in HBudtp-benzene-water system than in HBudtp-n-butanol-water system are explained by higher solubility of the complex species in nonpolar solvents. The position of the extraction curves in the pH-range lower than 0.7 reduces the complexation of thorium(IV) with Budtp - in the aqueous phase and also the hydrolysis process. (author) 8 refs.; 4 figs.; 1 tab

The stability of high-Tc BSCCO/Ag superconducting microcomposites in water, some inorganic solutions and organic solvents

International Nuclear Information System (INIS)

Gao, W.; Chen, J.; Yang, C.O.; McNabb, D.; Sande, J. vander

1992-01-01

Bi(Pb)-Sr-Ca-Cu-O/Ag (BSCCO/Ag) superconducting microcomposites with zero-resistance temperatures from 102 to 108 K and critical current densities of ∝600 A/cm 2 at 77 K were produced by oxidation and annealling of metallic precursor alloys. The stabilities and degradation behavior of BSCCO/Ag specimens in various environments were studied by a combination of mass loss measurement, electrical transport measurement and microstructural observation. The environmental conditions used in the present work were moist air, distilled water, aqueous solutions of NaCl, NaOH and acetic acid, and organic solvents methanol and acetone. Although there is a general tendency toward a decrease in critical current density after a long exposure to most of the testing conditions, the specimens containing a high percent of Ag (≥70 wt.%) showed very little decrease in Tc and J c up to 200 days of exposure in moist air and distilled water, and up to 20 days in NaCl solution, methanol and acetone. It was found that the superconducting ''2223'' phase is stable in water, neutral solutions and the organic solvents, reacts very slowly with basic solutions, and dissolves rapidly in acidic solutions. Some non-superconducting Ca-rich oxides dissolve in water and neutral and basic solutions and therefore damage the connection of the superconducting grains in low-Ag containing specimens. The excellent stability of the BSCCO/Ag superconducting microcomposites containing high Ag provides an important advantage for their potential industrial application. (orig.)

Solubility measurement and correlation of 4-nitrophthalimide in (methanol, ethanol, or acetone) + N,N-dimethylformamide mixed solvents at temperatures from 273.15 K to 323.15 K

International Nuclear Information System (INIS)

Li, Rongrong; Han, Shuo; Du, Cunbin; Cong, Yang; Wang, Jian; Zhao, Hongkun

2016-01-01

Highlights: • Solubility of 4-nitrophthalimide in binary mixed solvents were determined. • Solubility data were correlated and calculated by four models. • The standard dissolution enthalpy for the dissolution processes were calculated. - Abstract: The solubility of 4-nitrophthalimide in binary (methanol + N,N-dimethylformamide (DMF), ethanol + DMF) and (acetone + DMF) solvent mixtures were investigated by the isothermal dissolution equilibrium method under atmosphere pressure. These studies were carried out at different mass fractions of methanol, ethanol or acetone ranging from 0.1 to 0.9 at temperature T = (273.15–323.15) K. For the nine groups of each solvent mixture studied, the solubility of 4-nitrophthalimide in mixed solutions increased with increasing temperature and mass fraction of methanol, ethanol or acetone for the three systems including (methanol + DMF), (ethanol + DMF) and (acetone + DMF). At the same temperature and mass fraction of methanol, ethanol or acetone, the mole fraction solubility of 4-nitrophthalimide in (acetone + DMF) was greater than that in the other two binary solvents. In addition, the experimental mole fraction solubility was correlated by four models (Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, modified Apelblat–Jouyban–Acree model and Sun model). The Jouyban–Acree model gave best representation for the experimental solubility values. Furthermore, the standard molar enthalpies of 4-nitrophthalimide during the dissolving process (Δ sol H o ) were also obtained in this work, and the results show that the dissolution process is endothermic. The experimental solubility and the models used in this work will be helpful in separating 4-nitrophthalimide from its isomeric mixtures.

Effect of solvent-induced structural modifications on optical ...

Indian Academy of Sciences (India)

Administrator

use of methanol as solvent leads to a strong enhancement of PL intensity of CdS quantum dots for use in opto- electronic ... obtain a clearer understanding of the relative importance ... deionized water and ethanol several times and dried in.

A Simple Method for Automated Solid Phase Extraction of Water Samples for Immunological Analysis of Small Pollutants.

Science.gov (United States)

Heub, Sarah; Tscharner, Noe; Kehl, Florian; Dittrich, Petra S; Follonier, Stéphane; Barbe, Laurent

2016-01-01

A new method for solid phase extraction (SPE) of environmental water samples is proposed. The developed prototype is cost-efficient and user friendly, and enables to perform rapid, automated and simple SPE. The pre-concentrated solution is compatible with analysis by immunoassay, with a low organic solvent content. A method is described for the extraction and pre-concentration of natural hormone 17β-estradiol in 100 ml water samples. Reverse phase SPE is performed with octadecyl-silica sorbent and elution is done with 200 µl of methanol 50% v/v. Eluent is diluted by adding di-water to lower the amount of methanol. After preparing manually the SPE column, the overall procedure is performed automatically within 1 hr. At the end of the process, estradiol concentration is measured by using a commercial enzyme-linked immune-sorbent assay (ELISA). 100-fold pre-concentration is achieved and the methanol content in only 10% v/v. Full recoveries of the molecule are achieved with 1 ng/L spiked de-ionized and synthetic sea water samples.

Study to find the best extraction solvent for use with guava leaves (Psidium guajava L.) for high antioxidant efficacy.

Science.gov (United States)

Seo, Jongkwon; Lee, Soojung; Elam, Marcus L; Johnson, Sarah A; Kang, Jonghoon; Arjmandi, Bahram H

2014-03-01

The effects of guava leaves extracted using solvents of water, ethanol, methanol, and different concentrations of hydroethanolic solvents on phenolic compounds and flavonoids, and antioxidant properties have been investigated. The antioxidant capability was assessed based on 2,2-diphenyl-1-picrylhydrazyl radical and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging abilities, reducing power, and nitric oxide-and nitrate-scavenging activities. The results demonstrated that the antioxidant ability of guava leaf extracts has a strong relationship with phenolic compound content rather than flavonoid content. Phenolic compound content of water extracted guava leaves was higher compared to pure ethanol and methanol extracts. However, phenolic compound content extracted using hydroethanolic solvent was higher than water, whereas 50% hydroethanolic was observed to be the most effective solvent showing high antioxidant ability.

High throughput research and evaporation rate modeling for solvent screening for ethylcellulose barrier membranes in pharmaceutical applications.

Science.gov (United States)

Schoener, Cody A; Curtis-Fisk, Jaime L; Rogers, True L; Tate, Michael P

2016-10-01

Ethylcellulose is commonly dissolved in a solvent or formed into an aqueous dispersion and sprayed onto various dosage forms to form a barrier membrane to provide controlled release in pharmaceutical formulations. Due to the variety of solvents utilized in the pharmaceutical industry and the importance solvent can play on film formation and film strength it is critical to understand how solvent can influence these parameters. To systematically study a variety of solvent blends and how these solvent blends influence ethylcellulose film formation, physical and mechanical film properties and solution properties such as clarity and viscosity. Using high throughput capabilities and evaporation rate modeling, thirty-one different solvent blends composed of ethanol, isopropanol, acetone, methanol, and/or water were formulated, analyzed for viscosity and clarity, and narrowed down to four solvent blends. Brookfield viscosity, film casting, mechanical film testing and water permeation were also completed. High throughput analysis identified isopropanol/water, ethanol, ethanol/water and methanol/acetone/water as solvent blends with unique clarity and viscosity values. Evaporation rate modeling further rank ordered these candidates from excellent to poor interaction with ethylcellulose. Isopropanol/water was identified as the most suitable solvent blend for ethylcellulose due to azeotrope formation during evaporation, which resulted in a solvent-rich phase allowing the ethylcellulose polymer chains to remain maximally extended during film formation. Consequently, the highest clarity and most ductile films were formed. Employing high throughput capabilities paired with evaporation rate modeling allowed strong predictions between solvent interaction with ethylcellulose and mechanical film properties.

Dynamics of electron solvation in methanol: Excited state relaxation and generation by charge-transfer-to-solvent

International Nuclear Information System (INIS)

Elkins, Madeline H.; Williams, Holly L.; Neumark, Daniel M.

2015-01-01

The charge-transfer-to-solvent dynamics (CTTS) and excited state relaxation mechanism of the solvated electron in methanol are studied by time-resolved photoelectron spectroscopy on a liquid methanol microjet by means of two-pulse and three-pulse experiments. In the two-pulse experiment, CTTS excitation is followed by a probe photoejection pulse. The resulting time-evolving photoelectron spectrum reveals multiple time scales characteristic of relaxation and geminate recombination of the initially generated electron which are consistent with prior results from transient absorption. In the three-pulse experiment, the relaxation dynamics of the solvated electron following electronic excitation are measured. The internal conversion lifetime of the excited electron is found to be 130 ± 40 fs, in agreement with extrapolated results from clusters and the non-adiabatic relaxation mechanism

Dynamics of electron solvation in methanol: Excited state relaxation and generation by charge-transfer-to-solvent

Science.gov (United States)

Elkins, Madeline H.; Williams, Holly L.; Neumark, Daniel M.

2015-06-01

The charge-transfer-to-solvent dynamics (CTTS) and excited state relaxation mechanism of the solvated electron in methanol are studied by time-resolved photoelectron spectroscopy on a liquid methanol microjet by means of two-pulse and three-pulse experiments. In the two-pulse experiment, CTTS excitation is followed by a probe photoejection pulse. The resulting time-evolving photoelectron spectrum reveals multiple time scales characteristic of relaxation and geminate recombination of the initially generated electron which are consistent with prior results from transient absorption. In the three-pulse experiment, the relaxation dynamics of the solvated electron following electronic excitation are measured. The internal conversion lifetime of the excited electron is found to be 130 ± 40 fs, in agreement with extrapolated results from clusters and the non-adiabatic relaxation mechanism.

Dynamics of electron solvation in methanol: Excited state relaxation and generation by charge-transfer-to-solvent

Energy Technology Data Exchange (ETDEWEB)

Elkins, Madeline H.; Williams, Holly L. [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Neumark, Daniel M. [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2015-06-21

The charge-transfer-to-solvent dynamics (CTTS) and excited state relaxation mechanism of the solvated electron in methanol are studied by time-resolved photoelectron spectroscopy on a liquid methanol microjet by means of two-pulse and three-pulse experiments. In the two-pulse experiment, CTTS excitation is followed by a probe photoejection pulse. The resulting time-evolving photoelectron spectrum reveals multiple time scales characteristic of relaxation and geminate recombination of the initially generated electron which are consistent with prior results from transient absorption. In the three-pulse experiment, the relaxation dynamics of the solvated electron following electronic excitation are measured. The internal conversion lifetime of the excited electron is found to be 130 ± 40 fs, in agreement with extrapolated results from clusters and the non-adiabatic relaxation mechanism.

Antioxidative Polyphenols from Defatted Oilseed Cakes: Effect of Solvents

Directory of Open Access Journals (Sweden)

Sue-Siang Teh

2014-02-01

Full Text Available Defatted hemp, flax and canola seed cakes were extracted with different solvent systems namely methanol, ethanol, acetone, methanol 80%, acetone 80% and mixed solvent of methanol:acetone:water (MAW, 7:7:6, v/v/v. Each extract was analyzed for antioxidant capacity using ferric reducing/antioxidant power (FRAP and 2,2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging assays. MAW exhibited the highest extraction of phenolic and flavonoid contents in the seed cakes, followed by acetone 80% and methanol 80%. The antioxidant capacity was proportional to the polyphenols recovery in the extracts. Canola seed cakes possessed the highest recovery of polyphenols and antioxidant capacity, followed by hemp and flax seed cakes. MAW extract of canola contained total phenolic content, 2104.67 ± 2.52 mg GAE/100 g fresh weight; total flavonoids, 37.79 ± 0.04 mg LUE/100 g fresh weight; percentage inhibition of DPPH•, 33.03 ± 0.38%; FRAP assay, 8.78 ± 0.07 μmol Fe (II/g fresh weight. Identification of individual polyphenol compounds were performed HPLC. MAW extract of canola had the highest (P < 0.05 concentration of all individual polyphenols except gallic acid and catechin. Highest concentration of quercetin and luteolin in MAW extract of hemp was obtained among all solvent systems.

Gas chromatography/isotope ratio mass spectrometry: analysis of methanol, ethanol and acetic acid by direct injection of aqueous alcoholic and acetic acid samples.

Science.gov (United States)

Ai, Guomin; Sun, Tong; Dong, Xiuzhu

2014-08-15

Methanol, ethanol, and acetic acid are not easily extracted from aqueous samples and are susceptible to isotope fractionation in gas chromatography/isotope ratio mass spectrometry (GC/IRMS) analysis. Developing a direct dilution GC/IRMS method for aqueous samples, by adjusting the sample concentrations in common solvents to be similar to each other and using a fixed GC split ratio, is very convenient and important because any linearity effects caused by amount-dependent isotope fractionation can be avoided. The suitability of acetonitrile and acetone solvents for the GC/IRMS analysis of pure methanol, ethanol and acetic acid, and commercial liquor and vinegar samples was evaluated using n-hexane and water as control solvents. All the solvents including water were separated from the analyte on a HP-INNOWAX column and were diverted away from the combustion interface. The influence of liquor matrix on the ethanol GC/IRMS analyses was evaluated by adding pure ethanol to liquor samples. Acetonitrile and acetone gave similar δ(13) C values for pure ethanol and pure acetic acid to those obtained in water and n-hexane, and also gave similar δ(13) C values of ethanol in liquor and acetic acid in white vinegar to that obtained in water. For methanol analysis, acetonitrile and refined acetone gave similar δ(13) C values to that obtained in water, but n-hexane was not a suitable solvent. In addition, isotopic fractionation caused by solvent and solute interactions was observed. We recommend using acetonitrile for the GC/IRMS analysis of aqueous alcoholic samples, and acetone for the analysis of aqueous acetic acid samples. This direct dilution method can provide high accurate and precise GC/IRMS analysis of the relative changes in δ(13) C values of methanol, ethanol, and acetic acid. Copyright © 2014 John Wiley & Sons, Ltd.

Sorption and permeation of solutions of chloride salts, water and methanol in a Nafion membrane

International Nuclear Information System (INIS)

Villaluenga, J.P.G.; Barragan, V.M.; Seoane, B.; Ruiz-Bauza, C.

2006-01-01

The sorption of water-methanol mixtures containing a dissolved chloride salt in a Nafion 117 membrane, and their transport through the membrane under the driving force of a pressure gradient, have been studied. Both type of experiments was performed by using five different salts: lithium chloride, sodium chloride, cesium chloride, magnesium chloride and calcium chloride. It was observed that both the permeation flow through the membrane and the membrane swelling increase significantly with the methanol content of the solutions. These facts are attributed to the increase in wet membrane porosity, which brings about the increase of the mobility of solvents in the membrane, besides the increase of the mobility of the polymer pendant chains. In contrast, the influence of the type of electrolyte on the membrane porosity and permeability is not very important, with the exception of the CsCl solutions, which is probably due to the small hydration ability of the Cs + ion

Murine elongation factor 1 alpha (EF-1 alpha) is posttranslationally modified by novel amide-linked ethanolamine-phosphoglycerol moieties. Addition of ethanolamine-phosphoglycerol to specific glutamic acid residues on EF-1 alpha

International Nuclear Information System (INIS)

Whiteheart, S.W.; Shenbagamurthi, P.; Chen, L.; Cotter, R.J.; Hart, G.W.

1989-01-01

Elongation Factor 1 alpha (EF-1 alpha), an important eukaryotic translation factor, transports charged aminoacyl-tRNA from the cytosol to the ribosomes during poly-peptide synthesis. Metabolic radiolabeling with [ 3 H] ethanolamine shows that, in all cells examined, EF-1 alpha is the major radiolabeled protein. Radiolabeled EF-1 alpha has an apparent Mr = 53,000 and a basic isoelectric point. It is cytosolic and does not contain N-linked oligosaccharides. Trypsin digestion of murine EF-1 alpha generated two major [ 3 H]ethanolamine-labeled peptides. Three peptides were sequenced and were identical to two distinct regions of the human EF-1 alpha protein. Blank sequencing cycles coinciding with glutamic acid in the human cDNA-derived sequence were also found to release [ 3 H]ethanolamine, and compositional analysis of these peptides confirmed the presence of glutamic acid. Dansylation analysis demonstrates that the amine group of the ethanolamine is blocked. These results indicate that EF-1 alpha is posttranslationally modified by the covalent attachment of ethanolamine via an amide bond to at least two specific glutamic acid residues (Glu-301 and Glu-374). The hydroxyl group of the attached ethanolamine was shown by mass spectrometry and compositional analysis, to be further modified by the addition of a phosphoglycerol unit. This novel posttranslational modification may represent an important alteration of EF-1 alpha, comparable to the regulatory effects of posttranslational methylation of EF-1 alpha lysine residues

Water Quality of NPP Secondary Side with Combined Water Chemistry of Ammonia and Ethanolamine

International Nuclear Information System (INIS)

Rhee, In-H.; Jung, Hyun-jun; Cho, Daechul; Park, Byunggi

2012-09-01

Ammonia (AM) and Ethanolamine (ETA), as pH control additive agents, were injected to the secondary side in a Korean NPP for the even pH in the entire secondary system including the wet region and the condensate. Ammonia and ETA are dominant in the vapor and liquid phases, respectively, since the former and latter are more and less volatile than water in the temperature range of 30 to 300 . pH of 9.5 to 9.7 was maintained in the water-steam cycle at the concentrations of ammonia with ∼1.0 ppm and ETA of ∼1.8 ppm. From the standpoint of corrosion, i.g, concentration of Fe, the water quality of secondary side was improved by the combined water treatment of ammonia and ETA, compared to all volatile treatment of ammonia. The electrical conductivity was increased from 6 to 10 μS/cm due to the presence of organic carboxylates produced by the decomposition of ETA. ETA was broken down by <5% in steam generator and converted into formate, acetate, and glycolate, among which acetate was largely formed. But inorganic ions such as Na + , Cl - , and SO 4 2- are not changed because their ingress was not made and the selectivity of resin over those ions was not fairly altered. The runtime of demineralizer in steam generator blowdown was shortened by a third for a mixture of ammonia and ETA. Most of Fe was originated from the shell side of heat exchangers including the condenser as a result of corrosion. Fe was only eliminated by ion exchange demineralizers, i.e., 46% at CPP and 3% at SG BD and 70% of Fe oxides were accumulated at the steam generator, on the basis of Fe concentration at the final feedwater. In conclusion, ETA is preferable to ammonia for the enhancement of pH in the liquid phase of water-steam mixture such as the shell side of heat exchanger and also the full-flow operation of CPP is more desirable than partial-flow operation for the improved removal of corrosion products, regardless of hydrogen- or amine-type operation. (authors)

Thermodynamics of complexes formation by ITC in methanol/water = 9/1 (v/v) solution: A case study

Energy Technology Data Exchange (ETDEWEB)

Fisicaro, Emilia, E-mail: emilia.fisicaro@unipr.it [University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma (Italy); Compari, Carlotta; Bacciottini, Franco; Contardi, Laura [University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma (Italy); Carcelli, Mauro; Rispoli, Gabriele; Rogolino, Dominga [University of Parma, Department of Chemistry, Parco Area delle Scienze, 17/A, 43124 Parma (Italy)

2014-06-01

Graphical abstract: Integrase strand transfert inhibitors chelate the metal ions in the active site of HIV integrase. - Highlights: • Development of inhibitors acting against those viral enzymes operating via a cooperative two-metal ion mechanism, such as HIV integrase (IN), requires optimizing the binding affinity to the target. • We have defined an experimental procedure for obtaining reliable thermodynamic data by ITC in methanol/water = 9/1 (v/v) as solvent. • Formation heats in mixed solvent of the complexes formed by a ligand, model of Raltegravir, with Mg(II), Mn(II), Co(II) and Zn(II) are here reported. - Abstract: Most enzymes that participate in the biochemistry of nucleic acids require divalent metal ion cofactors to promote activity. Development of potent inhibitors, acting against those viral enzymes operating via a cooperative two-metal ion mechanism, such as HIV integrase (IN) and RNase H, hepatitis C virus polymerase and influenza endonuclease, requires optimizing the binding affinity to the target, which is dictated by the binding free energy composed of both enthalpic and entropic contributions. They can be obtained by using isothermal titration microcalorimetry. We have defined an experimental procedure for obtaining reliable thermodynamic data in methanol/water = 9/1 0.1 M KCl as solvent, used to overcome solubility problems. In this way we have measured the heats of formation of the complexes formed by N-(4-fluorobenzyl)-5-hydroxy-2-isopropyl-1-methyl-6-oxo-1, 6-dihydroxypyrimidine-4-carboxylate (HL, a model of Raltegravir, the antiretroviral drug produced by Merck and Co.), and a series of divalent metal ions of biological interest (Mg(II), Mn(II), Co(II) and Zn(II)), whose speciation was previously determined by potentiometry.

Mass Proportion, Bioactive Compounds and Antioxidant Capacity of Carrot Peel as Affected by Various Solvents

Directory of Open Access Journals (Sweden)

Van Tang Nguyen

2016-11-01

Full Text Available The aim of this study was to determine the mass proportion of carrot root and the effects of four various solvents (methanol, water, ethanol and hexane on the contents of total phenolics and saponins as well as antioxidant capacity of carrot peel to identify an optimal solvent for effective extraction of bioactive compounds from carrot peel for further investigation. The results showed that carrot root consisted of body, heads and peel with their mass proportion of 83.19%, 5.01% and 14.19% by fresh weight, respectively. Among four solvents tested, methanol obtained the highest levels of extraction yield (54.02% by dry weight, total phenolic content (9.02 mg GAE/g dry weight and antioxidant capacity (DPPH radical scavenging capacity, cupric ion reducing antioxidant capacity, and ferric reducing antioxidant power from carrot peel, while water extracted the highest content of saponins (272.9 mg EE/g dry weight and possessed the maximum ABTS radical scavenging capacity. Therefore, methanol and water are considered for effective extraction of phenolics and saponins from carrot peel, respectively. The phenolic/saponin-enriched extracts are potential sources for further applications in the healthy food and/or pharmaceutical industries.

The use of organic solvents in mutagenicity testing.

Science.gov (United States)

Abbondandolo, A; Bonatti, S; Corsi, C; Corti, G; Fiorio, R; Leporini, C; Mazzaccaro, A; Nieri, R; Barale, R; Loprieno, N

1980-10-01

13 organic substances (dimethylsulfoxide, methanol, ethanol, n-propyl alcohol, sec-butyl alcohol, tert-butyl alcohol, dl-sec-amyl alcohol, ethylene glycol, ethylene glycol monomethyl ether, 1,4-diethylene dioxide, acetone, methyl acetate and formamide) were considered from the standpoint of their use as solvents for water-insoluble chemicals to be tested for mutagenicity. First, the effect of these solvents on cell survival was studied in the yeast Schizosaccharomyces pombe and in V79 Chinese hamster cells. 8 solvents showing relatively low toxicity on either cell system (dimethylsulfoxide, ethanol, ethylene glycol, ethylene glycol monomethyl ether, 1,4-diethylene dioxide, acetone, methyl acetate and formamide) were tested for their effect on aminopyrine demethylase. 4 solvents (ethanol, 1,4-diethylene dioxide, methyl acetate and formamide) showed a more or less pronounced adverse effect on the microsomal enzymic activity. The remaining 4 and methanol (whose effect on aminopyrine demethylase was not testable) were assayed for mutagenicity in S. pombe. They all gave negative results both with and without the post-mitochondrial fraction from mouse liver.

Accumulation of N-acyl-ethanolamine phospholipids in rat brains during post-decapitative ischemia

DEFF Research Database (Denmark)

Moesgaard, B.; Hansen, Harald S.; Jaroszewski, J.W.

1999-01-01

-phospho(N-acyl)-ethanolamine (NAPE(PLAS)), respectively, by spiking with authentic materials. Additionally, the identification was verified by thin-layer chromatography, which also showed the accumulation of N-acyl-ethanolamine phospholipids. The use of K-EDTA instead of the commonly used Cs...

Use of high-boiling point organic solvents for pulping oil palm empty fruit bunches.

Science.gov (United States)

Rodríguez, Alejandro; Serrano, Luis; Moral, Ana; Pérez, Antonio; Jiménez, Luis

2008-04-01

Oil palm empty fruit bunches were used as an alternative raw material to obtain cellulosic pulp. Pulping was done by using high-boiling point organic solvents of decreased polluting power relative to classical (Kraft, sulphite) solvents but affording operation at similar pressure levels. The holocellulose, alpha-cellulose and lignin contents of oil palm empty fruit bunches (viz. 66.97%, 47.91% and 24.45%, respectively) are similar to those of some woody raw materials such as pine and eucalyptus, and various non-wood materials including olive tree prunings, wheat straw and sunflower stalks. Pulping tests were conducted by using ethyleneglycol, diethyleneglycol, ethanolamine and diethanolamine under two different sets of operating conditions, namely: (a) a 70% solvent concentration, 170 degrees C and 90 min; and (b) 80% solvent, 180 degrees C and 150 min. The solid/liquid ratio was six in both cases. The amine solvents were found to provide pulp with better properties than did the glycol solvents. Ethanolamine pulp exhibited the best viscosity and drainage index (viz. 636 mL/g and 17 degrees SR, respectively), and paper made from it the best breaking length (1709 m), stretch (1.95%), burst index (0.98 kN/g) and tear index (0.33 mNm(2)/g). Operating costs can be reduced by using milder conditions, which provide similar results. In any case, the amines are to be preferred to the glycols as solvents for this purpose.

Solubility determination and thermodynamic modelling of allisartan isoproxil in different binary solvent mixtures from T = (278.15 to 313.15) K and mixing properties of solutions

International Nuclear Information System (INIS)

Yang, Yaoyao; Yang, Peng; Du, Shichao; Li, Kangli; Zhao, Kaifei; Xu, Shijie; Hou, Baohong; Gong, Junbo

2016-01-01

Highlights: • The solubility of allisartan isoproxil in binary solvent mixtures were determined. • Apelblat, CNIBS/R-K and Jouyban-Acree models were used to correlate the solubility. • Solubility parameter theory was used to explain the co-solvency phenomenon. • Regular mixing rules were used to calculate solubility parameter of binary solvents. • The mixing thermodynamics were calculated and discussed based on NRTL model. - Abstract: In this work, the solubility of allisartan isoproxil in binary solvent mixtures, including (acetone + water), (acetonitrile + water) and (methanol + water), was determined by a gravimetric method with the temperature ranging from (278.15 to 313.15) K at atmospheric pressure (p = 0.1 MPa). The solubility of allisartan isoproxil in three binary solvent mixtures all increased with the rising of temperature at a constant solvent composition. For the binary solvent mixtures of (methanol + water), the solubility increased with the increasing of methanol fraction, while it appeared maximum value at a certain solvent composition in the other two binary solvent mixtures (acetone + water and acetonitrile + water). Based on the theory of solubility parameter, Fedors method and two mixing rules were employed to calculate the solubility parameters, by which the proximity of solubility parameters between allisartan isoproxil and binary solvent mixtures explained the co-solvent phenomenon. Additionally, the modified Apelblat equation, CNIBS/R-K model and Jouyban-Acree model were used to correlate the solubility data in binary solvent mixtures, and it turned out that all the three correlation models could give a satisfactory result. Furthermore, the mixing thermodynamic properties were calculated based on NRTL model, which indicated that the mixing process was spontaneous and exothermic.

Segment-segment interactions of poly(N-isopropylacrylamide) in aqueous methanol solutions by using small-angle scattering

International Nuclear Information System (INIS)

Shimizu, S.; Kurita, K.; Furusaka, M.

2002-01-01

Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)

Antifungal activity of methanolic root extract of Withania somnifera

African Journals Online (AJOL)

Proff.Adewunmi

remedy for many diseases in various regions of the world, especially in ... For control, 2 mL of DMSO was added to 16 mL of water, and 4 mL of this .... 3E). Since the four organic solvents used for fractionation of methanolic root .... Purification of a Lectin-Like Antifungal Protein from the Medicinal Herb, Withania Somnifera.

Phenolic Content and Antioxidant Activity of Hibiscus cannabinus L. Seed Extracts after Sequential Solvent Extraction

Directory of Open Access Journals (Sweden)

Shahid Iqbal

2012-10-01

Full Text Available A sequential solvent extraction scheme was employed for the extraction of antioxidant compounds from kenaf (Hibiscus cannabinus L. seeds. Yield of extracts varied widely among the solvents and was the highest for hexane extract (16.6% based on dry weight basis, while water extract exhibited the highest total phenolic content (18.78 mg GAE/g extract, total flavonoid content (2.49 mg RE/g extract, and antioxidant activities (p < 0.05. DPPH and hydroxyl radical scavenging, β-carotene bleaching, metal chelating activity, ferric thiocyanate and thiobarbituric acid reactive substances assays were employed to comprehensively assess the antioxidant potential of different solvent extracts prepared sequentially. Besides water, methanolic extract also exhibited high retardation towards the formation of hydroperoxides and thiobarbituric acid reactive substances in the total antioxidant activity tests (p < 0.05. As conclusion, water and methanol extracts of kenaf seed may potentially serve as new sources of antioxidants for food and nutraceutical applications.

A thermodynamic study of complexation process between N, N'-dipyridoxylidene(1,4-butanediamine) and Cd2+ in some binary mixed solvents using conductometry

Science.gov (United States)

Ebrahimpoor, Sonia; Khoshnood, Razieh Sanavi; Beyramabadi, S. Ali

2016-12-01

Complexation of the Cd2+ ion with N, N'-dipyridoxylidene(1,4-butanediamine) Schiff base was studied in pure solvents including acetonitrile (AN), ethanol (EtOH), methanol (MeOH), tetrahydrofuran (THF), dimethylformamide (DMF), water (H2O), and various binary solvent mixtures of acetonitrile-ethanol (AN-EtOH), acetonitrile-methanol (AN-MeOH), acetonitrile-tetrahydrofuran (AN-THF), acetonitrile-dimethylformamide (AN-DMF), and acetonitrile-water (AN-H2O) systems at different temperatures using the conductometric method. The conductance data show that the stoichiometry of complex is 1: 1 [ML] in all solvent systems. A non-linear behavior was observed for changes of log K f of [Cd( N, N'-dipyridoxylidene(1,4-butanediamine)] complex versus the composition of the binary mixed solvents, which was explained in terms of solvent-solvent interactions. The results show that the thermodynamics of complexation reaction is affected by the nature and composition of the mixed solvents.

Substituent effects on an inverse electron demand hetero Diels-Alder reaction in aqueous solution and organic solvents : Cycloaddition of substituted styrenes to di(2-pyridyl)-1,2,4,5-tetrazine

NARCIS (Netherlands)

Wijnen, Jan W.; Zavarise, Silvia; Engberts, Jan B.F.N.; Charton, Marvin

1996-01-01

The kinetics of the Diels-Alder reactions of di(2-pyridyl)-1,2,4,5-tetrazine (1) with substituted styrenes 2 was investigated in aqueous media and in organic solvents. The second-order rate constants ofthis reaction increase dramatically in water-rich media. A decrease in pH accelerates the aqueous

Effect of electrostatic interaction on thermochemical behavior of 12-crown-4 ether in various polar solvents

International Nuclear Information System (INIS)

Barannikov, Vladimir P.; Guseynov, Sabir S.; Vyugin, Anatoliy I.

2010-01-01

The enthalpies of solution of 12-crown-4 ether have been measured in chloroform, ethyl acetate, acetone, pyridine, acetonitrile and methanol at 298.15 K. The values of enthalpy of solvation and solute-solvent interaction were determined from the obtained results and similar literature data for 12-crown-4 in solvents of various polarities. It was shown that the certain correlation is observed between the enthalpy of solute-solvent interaction and the squared dipole moment of the solvent molecules for solutions in tetrachlormethane, ethyl acetate, pyridine, acetonitrile, DMF, DMSO and propylene carbonate. This means that the electrostatic interaction of 12-crown-4 with polar solvent molecules contributes significantly to the exothermic effect of solvation. The understated negative value was found for the enthalpy of interaction of 12-crown-4 with acetone that can be connected with domination of low polar conformer of the crown ether in acetone medium. The most negative values of enthalpy of solvation are observed for solutions in chloroform and water because of hydrogen bonding between O-atoms of crown ether and molecules of the indicated solvents. This effect is not observed for methanol. The negative coefficient of pairwise solute-solute interaction in methanol indicates that the effects of solvophobic solute-solute interaction and H-bonding of the ether molecule with chain associates of methanol are not evinced in the thermochemical behavior of 12-crown-4.

A ROBUST EIGHT–MEMBERED RING MOTIF IN THE HYDROGEN-BONDED STRUCTURE OF -(PHENYLAMINOPYRIDINIUM- DI(METHANESULFONYLAMIDATE

Directory of Open Access Journals (Sweden)

Karna Wijaya

2002-03-01

Full Text Available The compound was prepared by dissolving 2-(phenylaminopyridine (0.52 g ; 3.0 mmol and di(methanesulfonylamine (0.51 g; 3.0 mmol in 5 mL methanol. Slow partial evaporation of the solvent at low tempertaure (-30 oC gave a yield of 0.66 g (64% and crystals suitable for X-ray study (m.p. 150-152 oC. The single crystal X-ray result showed that the crystal system was trikline with space group P. The crystal structure of the title compound 2-(phenylaminopyridinium-di(methane-sulfonylamidate forms a robust antidromic ring motif type. The structure testifies to the persistence of the  in question, which was previously detected as a robust supramolecular synthon in 2-aminopyridinium di(benzenesulfonylamidate and in a series of onium di(methane-sulfonylamidates.   Keywords: supramolecule, hydrogen-bond

Comparison of ethanolamine and potassium hydroxide as quantitative trapping agents for radiolabeled CO2 in metabolism studies

International Nuclear Information System (INIS)

Medinsky, M.A.

1986-01-01

The efficiency of ethanolamine and potassium hydroxide (KOH) as trapping agents for CO 2 was determined using a flow of 500 mL/min through CO 2 absorption towers containing trapping solution. Radiolabeled 14 CO 2 was produced by acidification of suspensions containing Ba 14 CO 3 . Both 100% ethanolamine and 5M ethanolamine in 2-methoxyethanol were evaluated. With 200 mL of either solution, trapping efficiency of 14 CO 2 decreased when only 5% or less of the amount of ethanolamine available had reacted (22 mmoles of CO 2 ) trapped). In contrast, use of 200 mL of 1M or 5M KOH was effective in retaining 88 mmoles of CO 2 . This is equivalent to the amount of CO 2 produced by a rat over an 8-hr period. In summary, with flow rates commonly used in in vivo metabolism studies, the trapping efficiency of ethanolamine was far less than the theoretical efficiency. In these types of studies KOH would be a more suitable trapping agent or, if used, ethanolamine solutions must be changed frequently

Measurement of methanol diffusion coefficient in polymer electrode membrane by small NMR sensor. 1st report. Development of method of measure methanol diffusion coefficient and evaluation of measured results

International Nuclear Information System (INIS)

Ogawa, Kuniyasu; Haishi, Tomoyuki; Ito, Kohei

2010-01-01

A method for measuring the diffusion coefficient of methanol in a polymer electrolyte membrane (PEM) was developed using the NMR method. A circular coil of 0.6mm inside diameter was used as a small NMR sensor. The PEM was inserted in a penetration cell, where methanol solvent is supplied to one side of the PEM and nitrogen gas is supplied to the other side of the PEM. The small NMR sensor was placed on the nitrogen gas side of the PEM. The small NMR sensor detects the NMR signal from the methanol solvent which permeates the PEM. The CH and OH components of the methanol solvent were obtained from the NMR signal by spectral analysis. The methanol concentration in the PEM was determined by the ratio of CH to OH components. The methanol concentration was acquired at intervals of 30s and was measured for 2000s. After 1500 seconds, the methanol concentration in the PEM reaches a steady state. The final methanol concentration was about 20% of the methanol concentration of the solvent. It assumed that the diffusion phenomenon of methanol in a PEM was a one-dimensional transport phenomenon, and the time-dependent change of methanol concentration was analyzed by parameterizing the diffusion coefficient. The diffusion coefficient of methanol in a PEM was determined by comparison with the measurement result of the time change of methanol concentration and the analysis results. The concentration difference diffusion coefficient of methanol in PEM obtained using this method was 3.5 * 10 -10 m 2 /s. (author)

Segment-segment interactions of poly(N-isopropylacrylamide) in aqueous methanol solutions by using small-angle scattering

CERN Document Server

Shimizu, S; Furusaka, M

2002-01-01

Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D sub 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D sub 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)

Ion chromatographic determination of Di-n-butyl phosphate in degraded organic solvent

International Nuclear Information System (INIS)

Velavendan, P.; Pandey, N.K.; Kamachi Mudali, U.; Natarajan, R.

2011-01-01

In the present work a method for the determination of Di-n-butyl phosphate in organic streams using Ion Chromatography technique is developed and described here. The method involves the separation of Di-n-butyl phosphate (DBP) from 30% TBP-NPH (Tri-n-butylphosphate diluted in Normal Paraffin Hydrocarbon) and uranium/nitric acid matrix by an extraction of DBP in alkaline medium and subsequent ion-exchange separation in ion chromatography column followed by suppressed conductivity detection. Direct determination of DBP in lean/loaded organic solvent will lead to in accurate determination of DBP due to organic interference. DBP is quantified to lower limit of 1 ppm with 3% RSD. The results obtained with ion chromatographic technique are compared with those obtained by standard gas chromatographic technique. The developed method is much faster and total analysis can be completed within two hours. (author)

Chemometric study of the effects of PtRu:BH4-molar ratio and solvent used in the preparation of PtRu/C electrocatalysts for for direct methanol fuel cell anodes

Energy Technology Data Exchange (ETDEWEB)

Polanco, N.S.O.; Neto, A.O.; Spinace, E.V. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Tusi, M.M. [Universidade Regional Integrada do Alto Uruguai e das Missoes (URI), Santiago, RS (Brazil); Brandalise, M. [Instituto Federal Fluminense (IFF), Campos dos Goyracazes, RJ (Brazil)

2014-07-01

PtRu/C electrocatalysts were prepared by borohydride reduction method and a chemometric study was performed to evaluate the influence of the solvent (water and isopropyl alcohol) and amount of reducing agent (PtRu:BH4- molar ratios of 5 and 15) in maximum power density. In borohydride reduction method, a solution containing sodium hydroxide and sodium borohydride (NaBH4) is added to a mixture containing water, isopropyl alcohol, metallic precursors and the carbon support Vulcan XC72. The obtained materials were characterized by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Membrane Electrode Assemblies (MEA's) were produced and tests in single direct methanol fuel cells were performed. The amount of sodium borohydride used in the reduction showed more influence on the maximum power density than the change of solvent of the reaction. (author)

Optimization of HPLC method for the isolation of Hypericum perforatum L. methanol extract

Directory of Open Access Journals (Sweden)

Stamenković, J.

2013-12-01

Full Text Available St. John's Wort (Hypericum perforatum L. is one of the most studied plant species in the family Hypericaceae. The aim of this study was the identification of the constituents of methanol extract of H. perforatum and optimization of conditions for their isolation. The main components of the methanol extract were isolated on preparative ZORBAX Eclipse XDB C18 column with solvent system consisting of methanol and 1x10-2 M ammonium acetate in water. Constituents of the extract were identified by comparing their retention times with the retention times of the standards, with the literature data and the UV spectra. By varying the conditions of chromatography, the optimal conditions for isolation of the methanol extract constituents were determined: mobile phase consisting of methanol and 1x10-2 M ammonium acetate in water in ratio 1 : 1, sample concentration 100 mg/mL, sample volume 30 µL, flow 2 mL/min. Under these conditions 7 components of the methanol extract were isolated.

Changes in total phenol, flavonoid contents and anti-Lactobacillus activity of Callisia fragrans due to extraction solvent

Science.gov (United States)

Le, Thom; Cao, Diem Kieu; Pham, Thanh Vy; Huynh, Tan Dat; Ta, Nhat Thuy Anh; Nguyen, Ngoc Thao Linh; Nguyen, Huu Thanh; Le, Hue Huong; Bui, Anh Vo; Truong, Dieu-Hien

2018-04-01

Callisia fragrans is a wonder herb with many medicinal properties such as burn, dental diseases, cancer diseases and arthritis in folk medicine. It is noted that the phytochemical constituents and antimicrobial activity of traditional plants depend on not only the extracting method but also the solvent used for extraction. In this study, the effect of five extraction solvents (i.e., distilled water, 80% methanol, 80% ethanol, 80% ethyl acetate, and 80% chloroform) on yield, total phenolic content (TPC) and total flavonoid content (TFC) of Callisia leaves was determined. Besides, changes in anti-Lactobacillus fermentum activity of C. fragrans freeze-dried extract was also evaluated using disk-diffusion method. The recovery percentage of extractable yield of fresh leaves are ranged from 11.93% w/w for distilled water extract to 16.60% w/w for aqueous ethanol extracts. The yield of 80% aqueous methanol extract (16.27% w/w) is only slightly less than that of the ethanol extract. Significant differences were observed among TPC and TFC obtaining by 80% methanol (0.0522% and 0.0335% w/w, respectively) compared to other solvents (p < 0.05). TPC and TFC of C. fragrans extracts increase in the following order: distilled water < 80% chloroform < 80% ethyl acetate < 80% ethanol < 80% methanol. The results revealed that 80% aqueous methanol Calissia extracts has moderate inhibition (9.0 mm of inhibition zone for 1.5 mg/mL of extracts) of L. fermentum compared to standard antibacterial agent. Based on the study results, it can be concluded that the yield, TPC and TFC of C. frgrans extract varied with the extracting solvent. It also showed that Callisia extracts can prevent dental caries by inhibiting the growth of L. fermentum, towards new insights for treatment of dental caries.

The effect of various solvents on the back channel of solution-processed In-Ga-Zn-O thin-film transistors intended for biosensor applications

International Nuclear Information System (INIS)

Kim, Si Joon; Jung, Joohye; Yoon, Doo Hyun; Kim, Hyun Jae

2013-01-01

This study investigated the effects of exposing solution-processed In-Ga-Zn-O (IGZO) thin-film transistors (TFTs), intended for biosensor applications, to various solvents. Various solvents, such as the nonpolar solvent chlorobenzene and the polar solvents ethanol and deionized (DI) water, were dropped and adsorbed on exposed IGZO channel surfaces. All IGZO TFT devices exhibited a negative threshold voltage shift and a sub-threshold swing degradation, without an accompanying degradation in field-effect mobility. These variations depended on the dielectric constant of the solvents; with the exception of the IGZO TFT device exposed to DI water, they all gradually returned to their initial states.

The effect of organic water-miscible solvents on the extraction of uranium by TOA

International Nuclear Information System (INIS)

Shi Xiukun; Shen Xinghai; Pen Qixiu; Gao Hongchen

1989-01-01

The effect of organic water-miscible solvents, such as methanol, ethanol, acetone, dioxane, glycol, dimethylsulfoxide (DMSO), dimethylformamide (DMF), tetrahydrofurance (THF) in aqueous phase on the extraction of uranyl sulphate by tri-n-octylamine (TOA) has been investigated. All data obtained showed that the addition of alcohols, ketones etc. into aqueous phase brings about an increase of distribution ratio of uranium, whereas the addition of DMSO, DMF etc. brings about a decrease of distribution ratio of uranium. In the present study, the regularity and mechanism of extraction with TOA are further studied and discussed from the measurements of some physical properties, such as dielectric constant, interface tension etc

Experimental study and thermodynamic modeling for determining the effect of non-polar solvent (hexane)/polar solvent (methanol) ratio and moisture content on the lipid extraction efficiency from Chlorella vulgaris.

Science.gov (United States)

Malekzadeh, Mohammad; Abedini Najafabadi, Hamed; Hakim, Maziar; Feilizadeh, Mehrzad; Vossoughi, Manouchehr; Rashtchian, Davood

2016-02-01

In this research, organic solvent composed of hexane and methanol was used for lipid extraction from dry and wet biomass of Chlorella vulgaris. The results indicated that lipid and fatty acid extraction yield was decreased by increasing the moisture content of biomass. However, the maximum extraction efficiency was attained by applying equivolume mixture of hexane and methanol for both dry and wet biomass. Thermodynamic modeling was employed to estimate the effect of hexane/methanol ratio and moisture content on fatty acid extraction yield. Hansen solubility parameter was used in adjusting the interaction parameters of the model, which led to decrease the number of tuning parameters from 6 to 2. The results indicated that the model can accurately estimate the fatty acid recovery with average absolute deviation percentage (AAD%) of 13.90% and 15.00% for the two cases of using 6 and 2 adjustable parameters, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of quinoxaline 1,4-di-n-oxide derivatives on solid support using room temperature and microwave-assisted solvent-free procedures

International Nuclear Information System (INIS)

Gomez-Caro, Lilia C.; Sanchez-Sanchez, Mario; Bocanegra-Garcia, Virgilio; Rivera, Gildardo; Monge, Antonio

2011-01-01

We describe the synthesis of 12 new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives on solid supports with room temperature and microwave-assisted solvent-free procedures. Results show that solid supports have good catalytic activity in the formation of quinoxaline 1,4-di-N-oxide derivatives. We found that florisil and montmorillonite KSF and K10 could be used as new, easily available, inexpensive alternatives of catalysts. Additionally, room temperature and microwave-irradiation solvent-free synthesis was more efficient than a conventional procedure (Beirut reaction), reducing reaction time and increasing yield. (author)

Synthesis of quinoxaline 1,4-di-n-oxide derivatives on solid support using room temperature and microwave-assisted solvent-free procedures

Energy Technology Data Exchange (ETDEWEB)

Gomez-Caro, Lilia C.; Sanchez-Sanchez, Mario; Bocanegra-Garcia, Virgilio; Rivera, Gildardo [Universidad Autonoma de Tamaulipas, Reynosa (Mexico). Dept. de Farmacia y Quimica Medicinal; Monge, Antonio [Universidad de Navarra, Pamplona (Spain). Centro de Investigacion en Farmacobiologia Aplicada. Unidad de Investigacion y Desarrollo de Medicamentos

2011-07-01

We describe the synthesis of 12 new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives on solid supports with room temperature and microwave-assisted solvent-free procedures. Results show that solid supports have good catalytic activity in the formation of quinoxaline 1,4-di-N-oxide derivatives. We found that florisil and montmorillonite KSF and K10 could be used as new, easily available, inexpensive alternatives of catalysts. Additionally, room temperature and microwave-irradiation solvent-free synthesis was more efficient than a conventional procedure (Beirut reaction), reducing reaction time and increasing yield. (author)

Vapor-Liquid Equilibrium of Methane with Water and Methanol. Measurements and Modeling

DEFF Research Database (Denmark)

Frost, Michael Grynnerup; Karakatsani, Eirini; von Solms, Nicolas

2014-01-01

that rely on phase equilibrium data for optimization. The objective of this work is to provide experimental data for hydrocarbon systems with polar chemicals such as alcohols, glycols, and water. New vapor-liquid equilibrium data are reported for methane + water, methane + methanol, and methane + methanol...

Measurement and prediction of dabigatran etexilate mesylate Form II solubility in mono-solvents and mixed solvents

International Nuclear Information System (INIS)

Xiao, Yan; Wang, Jingkang; Wang, Ting; Ouyang, Jinbo; Huang, Xin; Hao, Hongxun; Bao, Ying; Fang, Wen; Yin, Qiuxiang

2016-01-01

Highlights: • Solubility of DEM Form II in mono-solvents and binary solvent mixtures was measured. • Regressed UNIFAC model was used to predict the solubility in solvent mixtures. • The experimental solubility data were correlated by different models. - Abstract: UV spectrometer method was used to measure the solubility data of dabigatran etexilate mesylate (DEM) Form II in five mono-solvents (methanol, ethanol, ethane-1,2-diol, DMF, DMAC) and binary solvent mixtures of methanol and ethanol in the temperature range from 287.37 K to 323.39 K. The experimental solubility data in mono-solvents were correlated with modified Apelblat equation, van’t Hoff equation and λh equation. GSM model and Modified Jouyban-Acree model were employed to correlate the solubility data in mixed solvent systems. And Regressed UNIFAC model was used to predict the solubility of DEM Form II in the binary solvent mixtures. Results showed that the predicted data were consistent with the experimental data.

Developmental and Reproductive Toxicology of Methanol

Science.gov (United States)

Methanol is a high production volume chemical used as a feedstock for chemical syntheses and as a solvent and fuel additive. Methanol is acutely toxic to humans, causing acidosis, blindness in death at high dosages, but its developmental and reproductive toxicity in humans is poo...

Reference value standards and primary standards for pH measurements in D2O and aqueous-organic solvent mixtures: new accessions and assessments

International Nuclear Information System (INIS)

Mussini, P.R.; Mussini, T.; Rondinini, S.

1997-01-01

Recommended Reference Value Standards based on the potassium hydro-genphthalate buffer at various temperatures are reported for pH measurements in various binary solvent mixtures of water with eight organic solvents: methanol, ethanol, 2-propanol, 1,2-ethanediol, 2-methoxyethanol (''methylcellosolve''), acetonitrile, 1,4-dioxane, and dimethyl sulfoxide, together with Reference Value Standard based on the potassium deuterium phthalate buffer for pD measurements in D 2 O. In addition are reported Primary Standards for pH based on numerous buffers in various binary solvent mixtures of water with methanol, ethanol, and dimethyl sulfoxide, together with Primary Standards for pD in D 2 O based on the citrate, phosphate and carbonate buffers. (author)

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

Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

International Nuclear Information System (INIS)

Lee, Youngme; Sah, Eric; Sah, Hongkee

2015-01-01

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

An ethanolamine kinase Eki1 affects radial growth and cell wall integrity in Trichoderma reesei.

Science.gov (United States)

He, Ronglin; Guo, Wei; Zhang, Dongyuan

2015-09-01

Ethanolamine kinase (ATP:ethanolamine O-phosphotransferase, EC 2.7.1.82) catalyzes the committed step of phosphatidylethanolamine synthesis via the CDP-ethanolamine pathway. The functions of eki genes that encode ethanolamine kinase have been intensively studied in mammalian cells, fruit flies and yeast. However, the role of the eki gene has not yet been characterized in filamentous fungi. In this study, Treki1, an ortholog of Saccharomyces cerevisiae EKI1, was identified and functionally characterized using a target gene deletion strategy in Trichoderma reesei. A Treki deletion mutant was less sensitive to cell wall stressors calcofluor white and Congo red and released fewer protoplasts during cell wall digestion than the parent strain QM9414. Further transcription analysis showed that the expression levels of five genes that encode chitin synthases were drastically increased in the ΔTreki1 mutant. The chitin content was also increased in the null mutant of Treki1 comparing to the parent strain. In addition, the ΔTreki1 mutant exhibited defects in radial growth, conidiation and the accumulation of ethanolamine. The results indicate that Treki1 plays a key role in growth and development and in the maintenance of cell wall integrity in T. reesei. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Prospettive della reazione di idroformilazione nella sintesi di composti biologicamente attivi

OpenAIRE

Marchetti, Mauro

2000-01-01

Il nostro gruppo sta conducendo uno studio su complessi di rodio con una nuova classe di leganti idrosolubili di origine proteica, tali complessi impiegati nell’idroformilazione bifasica in solvente acquoso di diversi substrati hanno fornito buoni risultati.

Influencing parameters of water and methanol transport in a big direct methanol fuel cell; Einflussgroessen auf den Wasser- und Methanoltransport einer groesseren Direkt-Methanol Brennstoffzelle

Energy Technology Data Exchange (ETDEWEB)

Schonert, Morten

2008-07-01

The author investigated the influencing parameters of water and methanol transport in a big direct methanol fuel cell (Pel > 1 kW) with the intention of making the direct methanol fuel cell system water-autonomous. As water is consumed during the electrochemical reaction on the anode while more water is produced on the cathode, the difference must be removed via the air. Any further water produced on the cathode must be condensed and recirculated to the anode. With increasing ambient temperature, the air volume flow must be reduced because otherwise more water would be removed than is acceptable. Low air volume flow on the cathode causes unstable cell voltage, which is also assumed to be caused by excess water production. For this reason, an attempt was made to prevent excess water production on the cathode by a system engineering approach. It was found that at the low air volume flow required for water autonomy, water permeation through the membrane-electrode aggregate (MEA) depends on the uptake capacity and on the time of residue of air over the cathode and less on the cathode material. Water permeation stops when the concentration gradient is balanced. Apart from the water permeation, there is also water transport through the Nafion {sup registered} membrane, i.e. so-called electroosmotic drag (ESD). This is an active transport mechanism that can also work against a concentration gradient. It could be shown that the EOD can be reduced by using water-impermeable materials for the gas diffusion layer on the anode. This will reduce the water volume that reaches the membrane, i.e. the water on the cathode. On the other hand, there was no measurable effect of the cathode design on water or methanol transport. The electrochemical performance of the membrane-electrode units under investigation was robust in case of many influencing parameters, e.g. dispersion, the conditions of MEA fabrication by hot pressing, themembrane thickness and the rate of methanol permeation

Unbiased water and methanol maser surveys of NGC 1333

Energy Technology Data Exchange (ETDEWEB)

Lyo, A-Ran; Kim, Jongsoo; Byun, Do-Young; Lee, Ho-Gyu, E-mail: arl@kasi.re.kr [Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro Yuseong-gu, Daejeon 305-348 (Korea, Republic of)

2014-11-01

We present the results of unbiased 22 GHz H{sub 2}O water and 44 GHz class I CH{sub 3}OH methanol maser surveys in the central 7' × 10' area of NGC 1333 and two additional mapping observations of a 22 GHz water maser in a ∼3' × 3' area of the IRAS4A region. In the 22 GHz water maser survey of NGC 1333 with a sensitivity of σ ∼ 0.3 Jy, we confirmed the detection of masers toward H{sub 2}O(B) in the region of HH 7-11 and IRAS4B. We also detected new water masers located ∼20'' away in the western direction of IRAS4B or ∼25'' away in the southern direction of IRAS4A. We could not, however, find young stellar objects or molecular outflows associated with them. They showed two different velocity components of ∼0 and ∼16 km s{sup –1}, which are blue- and redshifted relative to the adopted systemic velocity of ∼7 km s{sup –1} for NGC 1333. They also showed time variabilities in both intensity and velocity from multi-epoch observations and an anti-correlation between the intensities of the blue- and redshifted velocity components. We suggest that the unidentified power source of these masers might be found in the earliest evolutionary stage of star formation, before the onset of molecular outflows. Finding this kind of water maser is only possible through an unbiased blind survey. In the 44 GHz methanol maser survey with a sensitivity of σ ∼ 0.5 Jy, we confirmed masers toward IRAS4A2 and the eastern shock region of IRAS2A. Both sources are also detected in 95 and 132 GHz methanol maser lines. In addition, we had new detections of methanol masers at 95 and 132 GHz toward IRAS4B. In terms of the isotropic luminosity, we detected methanol maser sources brighter than ∼5 × 10{sup 25} erg s{sup –1} from our unbiased survey.

Extraction of glutathione from EFB fermentation waste using methanol with sonication process

Science.gov (United States)

Muryanto, Muryanto; Alvin, Nurdin, Muhammad; Hanifah, Ummu; Sudiyani, Yanni

2017-11-01

Glutathione is important compound on the human body. Glutathione have a widely use at pharmacy and cosmetics as detoxification, skin whitening agent, antioxidant and many other. This study aims to obtain glutathione from Saccharomyces cerevisiae in fermentation waste of second generation bioethanol. The remaining yeast in the empty fruit bunch (EFB) fermentation was separated from the fermentation solution use centrifugation process and then extracted using a methanol-water solution. The extraction process was done by maceration which was assisted by sonication process. Solvent concentration and time of sonication were varied to see its effect on glutathione concentration. The concentration of glutathione from the extraction process was analyzed using alloxan method with UV-Vis spectrophotometer. The results show that the highest glutathione concentration was approximately 1.32 g/L obtained with methanol solvent at 90 minutes of maceration following with 15 minutes sonication.

Evaluation of the antioxidant and antibacterial properties of various solvents extracts of Annona squamosa L. leaves

Directory of Open Access Journals (Sweden)

Ghadir A. El-Chaghaby

2014-04-01

Full Text Available The present work was conducted aiming to evaluate the effect of different solvent extracts on the antioxidant and antibacterial activities of Annona squamosa L. leaves. Four solvents were chosen for the study namely; methanol 80%, acetone 50%, ethanol 50% and boiling water. Acetone and boiling water gave the highest extraction yields as compared to methanol and ethanol. Total phenolic contents of the four extracts were significantly different with acetone being the most efficient solvent and water being the least efficient one. Correlation coefficient between the total antioxidant and total phenolic content was found to be R2 = 0.89 suggesting the contribution of phenolic compounds of the extract by 89% to its total antioxidant activity. The extracts were capable of scavenging H2O2 in a range of 43–54%. Reducing power of the extracts increased by increasing their concentration. The extracts were found to exert low to moderate antibacterial activity compared to a standard antibacterial agent. The bacterial inhibition of the extracts was found to positively correlate with their phenolic contents.

Studies of the role of water in the electrocatalysis of methanol oxidation

Science.gov (United States)

Lin, Andrew S.; Kowalak, Albert D.; O'Grady, William E.

The oxidation of methanol has been carried out on electrodes prepared by evaporating Pt directly onto a Nafion membrane and then introducing the methanol either in the gas-fed mode or directly from the electrolyte in the electrolyte-fed mode. It was found that the oxidation carried out using a gas-fed electrode was shifted 100-150 mV more cathodic than the electrolyte-fed electrode. A similar set of experiments was carried out using hydrophobic gas-diffusion electrodes and similar results were obtained. These results suggest that the mechanism of the methanol oxidation reaction depends on the nature of the surroundings and the orientation of the methanol with respect to the electrode surface. In the electrolyte-fed configuration the methanol will be in a hydrogen-bonded water cluster allowing the carbon end of the molecule to more readily approach the catalyst surface. While in the gas-fed configuration the methanol will interact with the water or oxidic surface through the hydroxyl end of the molecule. Clearly, these two possible mechanisms will lead to different products and one may enhance the rate of the direct oxidation of methanol as observed in this work.

Gradients in microbial methanol uptake: productive coastal upwelling waters to oligotrophic gyres in the Atlantic Ocean

Science.gov (United States)

Dixon, Joanna L; Sargeant, Stephanie; Nightingale, Philip D; Colin Murrell, J

2013-01-01

Methanol biogeochemistry and its importance as a carbon source in seawater is relatively unexplored. We report the first microbial methanol carbon assimilation rates (k) in productive coastal upwelling waters of up to 0.117±0.002 d−1 (∼10 nmol l−1 d−1). On average, coastal upwelling waters were 11 times greater than open ocean northern temperate (NT) waters, eight times greater than gyre waters and four times greater than equatorial upwelling (EU) waters; suggesting that all upwelling waters upon reaching the surface (⩽20 m), contain a microbial population that uses a relatively high amount of carbon (0.3–10 nmol l−1 d−1), derived from methanol, to support their growth. In open ocean Atlantic regions, microbial uptake of methanol into biomass was significantly lower, ranging between 0.04–0.68 nmol l−1 d−1. Microbes in the Mauritanian coastal upwelling used up to 57% of the total methanol for assimilation of the carbon into cells, compared with an average of 12% in the EU, and 1% in NT and gyre waters. Several methylotrophic bacterial species were identified from open ocean Atlantic waters using PCR amplification of mxaF encoding methanol dehydrogenase, the key enzyme in bacterial methanol oxidation. These included Methylophaga sp., Burkholderiales sp., Methylococcaceae sp., Ancylobacter aquaticus, Paracoccus denitrificans, Methylophilus methylotrophus, Methylobacterium oryzae, Hyphomicrobium sp. and Methylosulfonomonas methylovora. Statistically significant correlations for upwelling waters between methanol uptake into cells and both chlorophyll a concentrations and methanol oxidation rates suggest that remotely sensed chlorophyll a images, in these productive areas, could be used to derive total methanol biological loss rates, a useful tool for atmospheric and marine climatically active gas modellers, and air–sea exchange scientists. PMID:23178665

Optimal strategies for VOC emission abatement produced by solvent evaporation. The Italian case study; Strategie ottimali per la riduzione delle emissioni di composti organici volatili da uso di solventi: il caso italiano

Energy Technology Data Exchange (ETDEWEB)

Vetrella, G.; Cirillo, M.C. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

1998-07-01

This work analyses technologies and costs of VOC (volatile organic compounds) abatement in the activities which belong to the solvent evaporation sector, and then it singles out the most successful strategies from the costs point of view to reduce the sector emissions on the base of fixed abatement objectives. The Italian case is discussed. [Italian] Il lavoro analizza tecnologie e costi di abbattimento dei COV (composti organici volatili) nel settore evaporazione solventi, e individua la strategia piu' efficace dal punto di vista dei costi per ridurre le emissioni del settore sulla base di prefissati obiettivi di abbattimento. Analizza la situazione italiana.

Model-based analysis of water management in alkaline direct methanol fuel cells

Science.gov (United States)

Weinzierl, C.; Krewer, U.

2014-12-01

Mathematical modelling is used to analyse water management in Alkaline Direct Methanol Fuel Cells (ADMFCs) with an anion exchange membrane as electrolyte. Cathodic water supply is identified as one of the main challenges and investigated at different operation conditions. Two extreme case scenarios are modelled to study the feasible conditions for sufficient water supply. Scenario 1 reveals that water supply by cathodic inlet is insufficient and, thus, water transport through membrane is essential for ADMFC operation. The second scenario is used to analyse requirements on water transport through the membrane for different operation conditions. These requirements are influenced by current density, evaporation rate, methanol cross-over and electro-osmotic drag of water. Simulations indicate that water supply is mainly challenging for high current densities and demands on high water diffusion are intensified by water drag. Thus, current density might be limited by water transport through membrane. The presented results help to identify important effects and processes in ADMFCs with a polymer electrolyte membrane and to understand these processes. Furthermore, the requirements identified by modelling show the importance of considering water transport through membrane besides conductivity and methanol cross-over especially for designing new membrane materials.

Production of synthetic methanol from air and water using controlled thermonuclear reactor power

International Nuclear Information System (INIS)

Dang, V.D.; Steinberg, M.

1977-01-01

Energy requirement and process development of methanol production from air and water using controlled thermonuclear fusion power was discussed in Part 1 (Steinberg et al., Energy conversion;17:97(1977)). This second part presents an economic analysis of the nine processes presented for obtaining carbon dioxide recovery from the atmosphere or the sea for methanol production. It is found that the most economical process of obtaining carbon dioxide is by stripping from sea water. The process of absorption/stripping by dilute potassium carbonate solution is found to be the most economical for the extraction of carbon dioxide from air at atmospheric pressure. The total energy required for methanol synthesis from these sources of carbon dioxide is 3.90 kWh(e)/lb methanol of which 90% is used for generation of hydrogen. The process which consumes the greatest amount of energy is the absorption/stripping of air by water at high pressure and amounts to 13.2 kWh(e)/lb methanol. With nuclear fusion power plants of 1000to 9000 MW(e), it is found that the cost of methanol using the extraction of carbon dioxide from air with dilute potassium carbonate solution is estimated to be in the range between Pound1.73 and Pound2.90/MMB.t.u. (energy equivalent - 1974 cost) for plant capacities of 21 400 to 193 000 bbl/day methanol. This methanol cost is competitive with gasoline in the range of 19 approximately equal to 33c/gallon. For the process of stripping of carbon dioxide from sea water, the cost is found to lie in the range of Pound1.65 to Pound2.71/MMB.t.u. (energy equivalent) for plant capacities of 21 700 to 195 000 bbl/day methanol which is competitive with gasoline in the range of 18 approximately equal to 30 c/gallon. Projection of methanol demand in the year 2020 is presented based on both its conventional use as chemicals and as a liquid fuel substituting for oil and gas. (author)

Interference from ordinarily used solvents in the outcomes of Artemia salina lethality test

Directory of Open Access Journals (Sweden)

Sahgal Geethaa

2013-01-01

Full Text Available Methanol, ethanol, Tween 20 and dimethyl sulfoxide (DMSO are widely used as dissolving agents in Artemia salina lethality test (aka brine shrimp lethality test [BSLT] to screen the pharmaceutical properties of natural products. Nevertheless, there is lack of toxicity level of these solvents against brine shrimp. High concentration of these organic solvent might be toxic for this zoology invertebrate and interfere in the experimental outcomes. To avoid this, permissible concentration of the solvents used in BSLT was identified. BSLT was performed to evaluate the toxicity effect of Tween 20, methanol, ethanol and DMSO at 24 h post-treatment time point against A. salina. The suggested maximum working concentration (v/v for DMSO, methanol, ethanol was found to be 1.25% and that for Tween 20 was 0.16%. LC 50 for the solvents were 8.5% (DMSO, 6.4% (methanol, 3.4% (ethanol and 2.5% (Tween 20. The findings have shown a toxicity level among the solvents in descending order as Tween 20 > ethanol > methanol > DMSO. DMSO is a safer solvent to be used in BSLT compared with other tested solvents, whereas Tween 20 has been shown to be the most stringent solvent among the tested solvents. The findings are resourcefully useful to avoid interference of solvents in the assessment of natural products using BSLT.

Effect of Different Solvents on the Measurement of Phenolics and the Antioxidant Activity of Mulberry (Morus atropurpurea Roxb.) with Accelerated Solvent Extraction.

Science.gov (United States)

Yang, Jiufang; Ou, XiaoQun; Zhang, Xiaoxu; Zhou, ZiYing; Ma, LiYan

2017-03-01

The effects of 9 different solvents on the measurement of the total phenolics and antioxidant activities of mulberry fruits were studied using accelerated solvent extraction (ASE). Sixteen to 22 types of phenolics (flavonols, flavan-3-ols, flavanol, hydroxycinnamic acids, hydroxybenzoic acids, and stilbenes) from different mulberry extracts were characterized and quantified using HPLC-MS/MS. The principal component analysis (PCA) was used to determine the suitable solvents to distinguish between different classes of phenolics. Additionally, the phenolic extraction abilities of ASE and ultrasound-assisted extraction (UAE) were compared. The highest extraction efficiency could be achieved by using 50% acidified methanol (50MA) as ASE solvents with 15.14 mg/gallic acid equivalents g dry weight of mulberry fruit. The PCA results revealed that the 50MA followed by 50% acidified acetone (50AA) was the most efficient solvent for the extraction of phenolics, particularly flavonols (627.12 and 510.31 μg/g dry weight, respectively), while water (W) was not beneficial to the extraction of all categories of phenolics. Besides, the results of 3 antioxidant capability assays (DPPH, ABTS free radical-scavenging assay, and ferric-reducing antioxidant power assay) showed that water-based organic solvents increased the antioxidant capabilities of the extracts compared with water or pure organic solvents. ASE was more suitable for the extraction of phenolics than UAE. © 2017 Institute of Food Technologists®.

Membrane-based osmotic heat engine with organic solvent for enhanced power generation from low-grade heat.

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Shaulsky, Evyatar; Boo, Chanhee; Lin, Shihong; Elimelech, Menachem

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 OHE 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.

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.

Effects of solvents on the early stage stiffening rate of demineralized dentin matrix.

Science.gov (United States)

Garcia, Fernanda C P; Otsuki, Masayuki; Pashley, David H; Tay, Franklin R; Carvalho, Ricardo M

2005-05-01

To monitor the stiffening rate of demineralized dentin matrix at the early stages after exposure to different neat solvents. Dentin beams approximately 0.8x0.7x8.0 mm were obtained from human third molars. After covering their ends with resin composite, the middle exposed length of 4.0mm (gauge-length) was demineralized in 0.5 M EDTA (pH 7.0) for 7 days. The specimens were gripped by a testing machine, pre-loaded to 10 g and cyclically stressed in tension to 5% strain, for 30 repeated cycles (total 20 min) at 0.6 mm/min while immersed in water (control). Then, water was replaced by either 100% acetone, methanol, ethanol, propanol, HEMA or air and the specimens subjected to the same cyclic protocol. The maximum apparent modulus of elasticity (E(Max)) was calculated for every cycle, plotted as a function of time and subjected to regression analysis. Stiffening rate was calculated as changes in E (min). Regression analysis examined the relationship between E and time for each solvent. Data were analyzed by one-way ANOVA and Student-Newman-Keuls test at alpha=0.05. Regression analysis showed that E increased significantly with time in all water-free solvents (R2=0.8-0.99). Stiffening rate was higher for acetone (0.9 MPa/min) and ethanol (0.8 MPa/min), intermediate for air (0.7 MPa/min), methanol (0.6 MPa/min) and propanol (0.5 MPa/min), lower for HEMA (0.2 MPa/min) and practically none for water (0.07 MPa/min) with prate of demineralized dentin matrix is both time and solvent-dependent. The ability of solvents to promptly stiffen the demineralized dentin matrix may be important in maintaining the resin-infiltrated matrix expanded during the solvent evaporation stage of resin bonding.

Effect of the composition of a solution on the enthalpies of solvation of piperidine in methanol-acetonitrile and dimethylsulfoxide-acetonitrile mixed solvents

Science.gov (United States)

Kuz'mina, I. A.; Volkova, M. A.; Sitnikova, K. A.; Sharnin, V. A.

2014-01-01

Heat effects of dissolution of piperidine (ppd) are measured by calorimetry at 298.15 K over the range of composition of acetonitrile-methanol (AN-MeOH) mixed solvents. Based on the Δsol H ○(ppd)AN-MeOH values obtained using the literature data on Δsol H ○ (ppd) in acetonitrile-dimethylsulfoxide (AN-DMSO) mixed solvents and the vaporization enthalpy of ppd, the enthalpies of solvation of amine in AN-MeOH and AN-DMSO binary mixtures are calculated. A rise in the exothermicity of solvation of piperidine is observed upon the transition from AN to DMSO and MeOH, due mainly to the enhanced solvation of the amino group of ppd as a result of changes in the acid-base properties of the mixed solvent.

Solubility of daidzin in different organic solvents and (ethyl alcohol + water) mixed solvents

International Nuclear Information System (INIS)

Fan, Jie-Ping; Yang, Dan; Xu, Xiao-Kang; Guo, Xiao-Jie; Zhang, Xue-Hong

2015-01-01

Highlights: • The solubilities of daidzin were measured in various solvents. • The solubility data were correlated by three models. • The thermodynamic properties of the dissolution process were also determined. - Abstract: The solubility of daidzin in different organic solvents and (ethyl alcohol + water) mixed solvents was measured by high performance liquid chromatography (HPLC) analysis method from T = (283.2 to 323.2) K at atmosphere pressure. The results show that at higher temperature more daidzin dissolves, and moreover, the solubility increases with the ethyl alcohol mole fraction increase in the (ethyl alcohol + water) mixed solvents. The experimental solubility values were correlated by a simplified thermodynamic equation, λh equation and modified Apelblat equation. Based on the solubility of daidzin, the enthalpy and entropy of solution were also evaluated by van’t Hoff equation. The results illustrated that the dissolution process of daidzin is endothermic and entropy driven

Theoretical prediction of pKa in methanol: testing SM8 and SMD models for carboxylic acids, phenols, and amines.

Science.gov (United States)

Miguel, Elizabeth L M; Silva, Poliana L; Pliego, Josefredo R

2014-05-29

Methanol is a widely used solvent for chemical reactions and has solvation properties similar to those of water. However, the performance of continuum solvation models in this solvent has not been tested yet. In this report, we have investigated the performance of the SM8 and SMD models for pKa prediction of 26 carboxylic acids, 24 phenols, and 23 amines in methanol. The gas phase contribution was included at the X3LYP/TZVPP+diff//X3LYP/DZV+P(d) level. Using the proton exchange reaction with acetic acid, phenol, and ammonia as reference species leads to RMS error in the range of 1.4 to 3.6 pKa units. This finding suggests that the performance of the continuum models for methanol is similar to that found for aqueous solvent. Application of simple empirical correction through a linear equation leads to accurate pKa prediction, with uncertainty less than 0.8 units with the SM8 method. Testing with the less expensive PBE1PBE/6-311+G** method results in a slight improvement in the results.

The Effect of Time dealumination and Solvent Concentration in Synthesis of Zeolite Catalyst and Catalytic Test for DiEthyl Ether Production Process

International Nuclear Information System (INIS)

Widayat; Roesyadi, A.; Rachimoellah, M.

2009-01-01

Ethanol is an alternative energy, but its has three distinct disadvantages as a transportation fuel. Its availability is currently limited, and it has a lower volumetric heating value and a lower Reid vapour pressure (RVP) than gasoline. This paper focuses for this disadvantages and to solve this problem can do with converts ethanol to DiEthyl Ether product. This research produced DiEthyl Ether by ethanol dehydration process with zeolite as catalyst. The catalyst synthesis from natural material from District Gunung Kidul, Indonesia. The catalyst produced with dealumination, neutralization, drying and calcination processes. The zeolite catalyst was analysed of Si/Al, X-ray Diffraction and specific surface area. The catalyst product then used for ethanol dehydration to produce DiEthyl Ether. The results shown the biggest surface area is 184,52 m 2 /gram at catalyst production at 10 hours for time dealumination. The crystallite of catalyst product is similar like shown at diffractogram of XRD analysis. The ratio Si/Al biggest is 313.7 that obtaining at catalyst production with 7 hours for time dealumination. The catalytic test use fixed bed reactor with 1 inci diameter and ethanol fermentation both as feed. The operation condition is 150 deg. C at temperature and atmosphere pressure. The compounds product in liquid phase are diethyl ether, methanol and water.

Comparative responses of river biofilms at the community level to common organic solvent and herbicide exposure.

Science.gov (United States)

Paule, A; Roubeix, V; Swerhone, G D W; Roy, J; Lauga, B; Duran, R; Delmas, F; Paul, E; Rols, J L; Lawrence, J R

2016-03-01

Residual pesticides applied to crops migrate from agricultural lands to surface and ground waters. River biofilms are the first aquatic non-target organisms which interact with pesticides. Therefore, ecotoxicological experiments were performed at laboratory scale under controlled conditions to investigate the community-level responses of river biofilms to a chloroacetanilide herbicide (alachlor) and organic solvent (methanol) exposure through the development referenced to control. Triplicate rotating annular bioreactors, inoculated with river water, were used to cultivate river biofilms under the influence of 1 and 10 μg L(-1) of alachlor and 25 mg L(-1) of methanol. For this purpose, functional (thymidine incorporation and carbon utilization spectra) and structural responses of microbial communities were assessed after 5 weeks of development. Structural aspects included biomass (chlorophyll a, confocal laser scanning microscopy) and composition (fluor-conjugated lectin binding, molecular fingerprinting, and diatom species composition). The addition of alachlor resulted in a significant reduction of bacterial biomass at 1 μg L(-1), whereas at 10 μg L(-1), it induced a significant reduction of exopolymer lectin binding, algal, bacterial, and cyanobacterial biomass. However, there were no changes in biofilm thickness or thymidine incorporation. No significant difference between the bacterial community structures of control and alachlor-treated biofilms was revealed by terminal restriction fragment length polymorphism (T-RFLP) analyses. However, the methanol-treated bacterial communities appeared different from control and alachlor-treated communities. Moreover, methanol treatment resulted in an increase of bacterial biomass and thymidine incorporation as well. Changes in dominant lectin binding suggested changes in the exopolymeric substances and community composition. Chlorophyll a and cyanobacterial biomass were also altered by methanol. This study suggested

Method for obtaining water-free or largely water-free formic acid. Verfahren zur Gewinnung von wasserfreier oder weitgehend wasserfreier Ameisensaeure

Energy Technology Data Exchange (ETDEWEB)

Wolf, D; Schmidt, R; Block, U; Schoenmakers, H; Bott, K; Kaibel, G

1980-10-23

The formic acid was prepared by hydrolysis of methyl formate, distillation of methanol and methyl formate from the hydrolyzate, extraction of the residue with a solvent, e.g., a carboxamide, distillation of the extract containing solvent, formic acid, and water to remove all or most of the water and part of the formic acid at the head of the column, and separation of the extraction solvent from the product.

The use of 14C ethanolamine as a precursor

International Nuclear Information System (INIS)

Madelmont, J.C.; Parry, D.; Godeneche, D.; Duprat, J.

1985-01-01

Two new 2 chloroethyl nitrosoureas were labelled on two positions by 14 C starting from Na 14 CN and using 14 C ethanolamine as intermediate, i.e. on the carbon 2 of the 2 chloro ethyl group and on the carbon 2 of the cysteamine part. (author)

Comparison of the SRK and CPA equations of state for physical properties of water and methanol

DEFF Research Database (Denmark)

Lundstrøm, Carsten; Michelsen, Michael Locht; Kontogeorgis, Georgios

2006-01-01

produced together with water, properties of water and additives like methanol and glycol is another target area. Being more polar than hydrocarbons, water, alcohols and glycols may require more advanced models for example an association model like CPA (CubicPlus-Association). This type of model has...... previously been found to be well suited for phase equilibrium calculations on mixtures of hydrocarbons and polar compounds. In this work, SRK (with and without Peneloux volume correction) and CPA are compared for pure water, pure methanol and water-methanol binary mixtures with the purpose of evaluating...

A CNT (carbon nanotube) paper as cathode gas diffusion electrode for water management of passive μ-DMFC (micro-direct methanol fuel cell) with highly concentrated methanol

International Nuclear Information System (INIS)

Deng, Huichao; Zhang, Yufeng; Zheng, Xue; Li, Yang; Zhang, Xuelin; Liu, Xiaowei

2015-01-01

A novel MEA (membrane electrode assembly) structure of passive μ-DMFC (micro-direct methanol fuel cell) controls water management and decreases methanol crossover. The CNT (carbon nanotube) paper replacing CP (carbon paper) as GDL (gas diffusion paper) enhances water back diffusion which passively prevents flooding in the cathode and promotes low methanol crossover. Moreover, the unique structure of CNT paper can also enhance efficiency of oxygen mass transport and catalyst utilization. The passive μ-DMFC with CNT-MEA exhibits significantly higher performance than passive μ-DMFC with CP-MEA and can operate in high methanol concentration, showing the peak power density of 23.2 mW cm −2 . The energy efficiency and fuel utilization efficiency are obviously improved from 11.54% to 22.7% and 36.61%–49.34%, respectively, and the water transport coefficient is 0.47 which is lower than previously reported passive μ-DMFC with CP. - Highlights: • This novel GDL (gas diffusion layer) solves water management and methanol crossover. • This GDL creates a hydraulic pressure in the cathode increasing water back diffusion. • This GDL improves the electrical conductivity and activity of catalyst

On-line micro-volume introduction system developed for lower density than water extraction solvent and dispersive liquid–liquid microextraction coupled with flame atomic absorption spectrometry

International Nuclear Information System (INIS)

Anthemidis, Aristidis N.; Mitani, Constantina; Balkatzopoulou, Paschalia; Tzanavaras, Paraskevas D.

2012-01-01

Highlights: ► A dispersive liquid–liquid micro extraction method for lead and copper determination. ► A micro-volume transportation system for extractant solvent lighter than water. ► Analysis of natural water samples. - Abstract: A simple and fast preconcentration/separation dispersive liquid–liquid micro extraction (DLLME) method for metal determination based on the use of extraction solvent with lower density than water has been developed. For this purpose a novel micro-volume introduction system was developed enabling the on-line injection of the organic solvent into flame atomic absorption spectrometry (FAAS). The effectiveness and efficiency of the proposed system were demonstrated for lead and copper preconcentration in environmental water samples using di-isobutyl ketone (DBIK) as extraction solvent. Under the optimum conditions the enhancement factor for lead and copper was 187 and 310 respectively. For a sample volume of 10 mL, the detection limit (3 s) and the relative standard deviation were 1.2 μg L −1 and 3.3% for lead and 0.12 μg L −1 and 2.9% for copper respectively. The developed method was evaluated by analyzing certified reference material and it was applied successfully to the analysis of environmental water samples.

B-DNA model systems in non-terran bio-solvents : Implications for structure, stability and replication

NARCIS (Netherlands)

Hamlin, Trevor A.; Poater, Jordi; Fonseca Guerra, Célia; Bickelhaupt, F. Matthias

2017-01-01

We have computationally analyzed a comprehensive series of Watson-Crick and mismatched B-DNA base pairs, in the gas phase and in several solvents, including toluene, chloroform, ammonia, methanol and water, using dispersion-corrected density functional theory and implicit solvation. Our analyses

Terahertz sensing of highly absorptive water-methanol mixtures with multiple resonances in metamaterials.

Science.gov (United States)

Chen, Min; Singh, Leena; Xu, Ningning; Singh, Ranjan; Zhang, Weili; Xie, Lijuan

2017-06-26

Terahertz sensing of highly absorptive aqueous solutions remains challenging due to strong absorption of water in the terahertz regime. Here, we experimentally demonstrate a cost-effective metamaterial-based sensor integrated with terahertz time-domain spectroscopy for highly absorptive water-methanol mixture sensing. This metamaterial has simple asymmetric wire structures that support multiple resonances including a fundamental Fano resonance and higher order dipolar resonance in the terahertz regime. Both the resonance modes have strong intensity in the transmission spectra which we exploit for detection of the highly absorptive water-methanol mixtures. The experimentally characterized sensitivities of the Fano and dipole resonances for the water-methanol mixtures are found to be 160 and 305 GHz/RIU, respectively. This method provides a robust route for metamaterial-assisted terahertz sensing of highly absorptive chemical and biochemical materials with multiple resonances and high accuracy.

Evaluation of the lemongrass plant (Cymbopogon citratus extracted in different solvents for antioxidant and antibacterial activity against human pathogens

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Balachandar Balakrishnan

2014-02-01

Full Text Available Objective: To test antibacterial and antioxidant activity of the lemongrass plant Cymbopogon citratus (C. citratus leaves extracted serially by the solvents (chloroform, methanol and water. Methods: The plant leaves extracts were used for antibacterial activity on Bacillus subtilis, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Nocardia sp., Serratia sp., and Enterobacter aeruginosa microorganisms by the Kirby Bauer agar disc diffusion method. This study was carried out on lemongrass plant leaf extracts in different concentration of all solvents. The leaf extracts from different solvents were tested for their scavenging activity against the stable free radical DPPH in quantization using a spectrophotometric assay. Oxidative damage was induced in vitro by treating blood DNA and analyzing the effects of the leaf extracts. Results: The results showed that C. citratus extracts exhibited maximum zones of inhibition in chloroform, methanol and water extracts. It was Observed that the C. citratus extracts exhibited maximum zone of inhibition against Bacillus subtilis, Pseudomonas aeruginosa and Proteus vulgaris. Analyzed data in the present work suggested that antibacterial activity of C. citratus plant leaf extracts showed good results for Gram-positive and Gram-negative organisms. DPPH scavenging activity was highly elicited by the extract of C. citratus. Chloroform, methanol and water extracts of C. citratus leaves effectively decreased the extent of DNA damage. Conclusions: The present study suggested that the lemongrass plant extracts could offer various health benefits.

Study of the effect of anions and mixed solvents on the kinetics of reduction of Eu(III)

International Nuclear Information System (INIS)

Chandrasekaran, V.R.; Sundaram, A.K.

1983-01-01

The kinetics of reduction of Eu(III) to Eu(II) in aqueous solutions of perchlorate, chloride, sulphate, acetate and lactate anions and water-methanol and water-acetone mixtures containing potassium chloride as the inert electrolyte is reported and the effect of anions and solvent on the kinetics is studied. (author)

Etude de pratiques d'enseignement relatives a la modelisation en sciences et technologies avec des enseignants du secondaire

Science.gov (United States)

Aurousseau, Emmanuelle

Les modeles sont des outils amplement utilises en sciences et technologies (S&T) afin de representer et d’expliquer un phenomene difficilement accessible, voire abstrait. La demarche de modelisation est presentee de maniere explicite dans le programme de formation de l’ecole quebecoise (PFEQ), notamment au 2eme cycle du secondaire (Quebec. Ministere de l'Education du Loisir et du Sport, 2007a). Elle fait ainsi partie des sept demarches auxquelles eleves et enseignants sont censes recourir. Cependant, de nombreuses recherches mettent en avant la difficulte des enseignants a structurer leurs pratiques d’enseignement autour des modeles et de la demarche de modelisation qui sont pourtant reconnus comme indispensables. En effet, les modeles favorisent la conciliation des champs concrets et abstraits entre lesquels le scientifique, meme en herbe, effectue des allers-retours afin de concilier le champ experimental de reference qu’il manipule et observe au champ theorique relie qu’il construit. L’objectif de cette recherche est donc de comprendre comment les modeles et la demarche de modelisation contribuent a faciliter l’articulation du concret et de l’abstrait dans l’enseignement des sciences et des technologies (S&T) au 2eme cycle du secondaire. Pour repondre a cette question, nous avons travaille avec les enseignants dans une perspective collaborative lors de groupes focalises et d’observation en classe. Ces dispositifs ont permis d’examiner les pratiques d’enseignement que quatre enseignants mettent en oeuvre en utilisant des modeles et des demarches de modelisation. L’analyse des pratiques d’enseignement et des ajustements que les enseignants envisagent dans leur pratique nous permet de degager des connaissances a la fois pour la recherche et pour la pratique des enseignants, au regard de l’utilisation des modeles et de la demarche de modelisation en S&T au secondaire.

Regeneration of furfural on activated carbon with methanol; Furufuraru kyuchakutan no metanoru ni yoru saisei

Energy Technology Data Exchange (ETDEWEB)

Sudo, Y. [Tokyo National College of Technology, Tokyo (Japan); Suzuki, M. [Tokyo Univ. (Japan). Inst. of Industrial Science

1998-03-01

Experiments of regenerating solvent from activated carbon are performed using furfural (1-phenyl-2-propane) as the absorbent and methanol as the solvent for regeneration. In 5 repeated adsorption-desorption cycles, the solvent becomes in dynamic stationary state after the second cycle with about 10% not desorption yet, and it is found that considerable number of repetition of furfural adsorbed carbon regeneration is possible by the use of methanol. The overall mass transfer coefficient of furfural and methanol in desorption is calculated. In addition, an experiment is carried out changing the adsorption ratio of furfural and the flow velocity of methanol to investigate desorption mechanism of furfural adsorbed carbon. Larger difference of adsorption equilibrium of furfural in aqueous solution and in methanol is efficient in desorption of furfural adsorbed carbon by methanol, but it is found that desorption rate is affected by mixed diffusion in the column and the surface diffusion is dominant in particles. 17 refs., 10 figs.

Conformation Analysis of T1 Lipase on Alcohols Solvent using Molecular Dynamics Simulation

Science.gov (United States)

Putri, A. M.; Sumaryada, T.; Wahyudi, S. T.

2017-07-01

Biodiesel usually is produced commercially via a transesterification reaction of vegetable oil with alcohol and alkali catalyst. The alkali catalyst has some drawbacks, such as the soap formation during the reaction. T1 Lipase enzyme had been known as a thermostable biocatalyst which is able to produce biodiesel through a cleaner process. In this paper the performance of T1 lipase enzyme as catalyst for transesterification reaction in pure ethanol, methanol, and water solvents were studied using a Molecular Dynamics (MD) Simulation at temperature of 300 K for 10 nanoseconds. The results have shown that in general the conformation of T1 lipase enzyme in methanol is more dynamics as shown by the value of root mean square deviation (RMSD), root mean squared fluctuation (RMSF), and radius of gyration. The highest solvent accessible surface area (SASA) total was also found in methanol due to the contribution of non-polar amino acid in the interior of the protein. Analysis of MD simulation has also revealed that the enzyme structure tend to be more rigid in ethanol environment. The analysis of electrostatic interactions have shown that Glu359-Arg270 salt-bridge pair might hold the key of thermostability of T1 lipase enzyme as shown by its strong and stable binding in all three solvents.

Essential roles of protein-solvent many-body correlation in solvent-entropy effect on protein folding and denaturation: Comparison between hard-sphere solvent and water

International Nuclear Information System (INIS)

Oshima, Hiraku; Kinoshita, Masahiro

2015-01-01

In earlier works, we showed that the entropic effect originating from the translational displacement of water molecules plays the pivotal role in protein folding and denaturation. The two different solvent models, hard-sphere solvent and model water, were employed in theoretical methods wherein the entropic effect was treated as an essential factor. However, there were similarities and differences in the results obtained from the two solvent models. In the present work, to unveil the physical origins of the similarities and differences, we simultaneously consider structural transition, cold denaturation, and pressure denaturation for the same protein by employing the two solvent models and considering three different thermodynamic states for each solvent model. The solvent-entropy change upon protein folding/unfolding is decomposed into the protein-solvent pair (PA) and many-body (MB) correlation components using the integral equation theories. Each component is further decomposed into the excluded-volume (EV) and solvent-accessible surface (SAS) terms by applying the morphometric approach. The four physically insightful constituents, (PA, EV), (PA, SAS), (MB, EV), and (MB, SAS), are thus obtained. Moreover, (MB, SAS) is discussed by dividing it into two factors. This all-inclusive investigation leads to the following results: (1) the protein-water many-body correlation always plays critical roles in a variety of folding/unfolding processes; (2) the hard-sphere solvent model fails when it does not correctly reproduce the protein-water many-body correlation; (3) the hard-sphere solvent model becomes problematic when the dependence of the many-body correlation on the solvent number density and temperature is essential: it is not quite suited to studies on cold and pressure denaturating of a protein; (4) when the temperature and solvent number density are limited to the ambient values, the hard-sphere solvent model is usually successful; and (5) even at the ambient

Characterization and Storage Stability Study of Bixin Extracted from Bixa orellana Using Organic Solvent

Science.gov (United States)

Husa, N. N.; Hamzah, F.; Said, H. M.

2018-05-01

Colorant is one of the additives to give a better appearance or improve the colour of the product. Synthetic colorant has been widely used in industrial due to its readiness in the market and its colour stability. However the arising issues related to the safety, nutrition and also the therapeutic effect has encouraged users to become more concern about the colouring component. Thus, the present research was conducted in order to produce natural colorant called bixin from Bixa orellana or also known as annatto seeds. The study was focusing on the effect of the solvent on the characteristic and concentration of the extracted bixin. While stability of the bixin during different storage condition was determined to further validate the effectiveness of the solvent. The result indicated that methanol and acetone gave darker of the bixin colour as compared to the water. However, the deterioration rate of the bixin in acetone and methanol were faster as compared to the water. The extracted bixin was analysed using Fourier-transform infrared spectroscopy (FTIR) and spectrophotometer analysis. The strong band for the bixin was observed at absorbance range of 1704 – 1740cm-1. The study indicates that the concentration of the extracted bixin was the highest in methanol which gave 817.7 ppm of bixin. Meanwhile, bixin concentration in acetone and water was 602.9 ppm and 477.19 ppm respectively.

Effect of the solvent in the catalyst ink preparation on the properties and performance of unsupported PtRu catalyst layers in direct methanol fuel cells

International Nuclear Information System (INIS)

Alcaide, Francisco; Álvarez, Garbiñe; Cabot, Pere L.; Genova-Koleva, Radostina; Grande, Hans-Jürgen; Miguel, Oscar

2017-01-01

The effect of the organic solvent polarity on the properties of unsupported PtRu catalyst inks and on the performance of the catalyst layers prepared with them for the methanol electrooxidation, has been studied. The light scattering results indicate that the PtRu-Nafion ® aggregates in the inks prepared with n-butyl acetate (NBA) are larger than those prepared with 2-propanol (IPA). The lower polarity of the former favours the aggregation of Nafion ® and nanoparticles. The electron microscopy images and porosimetry measurements of the catalyst layers show that the secondary pore volume between the agglomerates is larger for NBA. The linear sweep voltammetry and eis results for the methanol electrooxidation in the three-electrode cell denote the higher active surface area for NBA and comparable specific oxidation rates of the intermediates in both catalysts layers. The current densities for PtRu anode catalyst layers in single DMFC are higher when the solvent is NBA, the mass transport limitations being much more apparent with IPA. The adapted transmission line equivalent circuit to interpret the impedance results in single DMFC indicates that the proton resistance for NBA is significantly lower than for IPA, thus suggesting that the greater number of accessible active sites for methanol oxidation in the former are well connected to the Nafion ® ionomers and easier transported to the membrane.

Effects of Extraction Solvents on the Quantification of Free Amino Acids in Lyophilised Brewer’s Yeast

Directory of Open Access Journals (Sweden)

Andreea STĂNILĂ

2018-05-01

Full Text Available The aim of this work was to test some solvents in order to improve the free amino acids extraction from lyophilised brewer’s yeast. The brewer’ yeast was treated with four types of extraction solvents: Solvent I – acetonitrile 25%/HCl 0.01M (ACN; Solvent II – ethanol 80%; solvent III – HCl 0.05M/deionized water (1/1 volume; Solvent IV – HCl 0.05M/ethanol 80% (1/1 volume. The supernatants were analysed by HPLC-DAD-ESI-MS method. Acetonitrile provided the less quantities and number of amino acids extracted due to its weaker polarity. Solvent II and IV (ethanol, respectively acidified ethanol, which have an increased polarity, extracted 15 amino acids due to the addition of HCl in solvent IV. Solvent III (acidified water proved to be the best extraction solvent for the amino acids from brewer’s yeast providing the separation of 17 compounds: GLN, ASN, SER, GLY, ALA, ORN, PRO, HIS, LYS, GLU, TRP, LEU, PHE, ILE, AAA, HPHE, TYR.

Design of optimal solvent for extraction of bio–active ingredients from six varieties of Medicago sativa

Directory of Open Access Journals (Sweden)

Caunii Angela

2012-10-01

Full Text Available Abstract Background Extensive research has been performed worldwide and important evidences were collected to show the immense potential of plants used in various traditional therapeutic systems. The aim of this work is to investigate the different extracting solvents in terms of the influence of their polarity on the extracting ability of bioactive molecules (phenolic compounds from the M. sativa flowers. Results The total phenolic content of samples was determined using the Folin Ciocalteu (FC procedure and their antioxidant activity was assayed through in vitro radical decomposing activity using the radical DPPH° assay (IUPAC name for DPPH is (phenyl–(2,4,6–trinitrophenyl iminoazanium. The results showed that water was better than methanol and acetic acid for extracting bioactive compounds, in particular for total phenolic compounds from the flowers of alfalfa. The average content of bioactive molecules in methanol extract was 263.5±1.02 mg GAE/100g of dry weight lyophilized extract. The total phenolic content of the tested plant extracts was highly correlated with the radical decomposing activity. However, all extracts were free–radical inhibitors, but the water extract was more potent than the acetic and the methanol ones. The order of inhibitor effectiveness (expressed by IC50 proved to be: water extract (0.924mg/mL > acetic acid extract (0.154mg/mL > methanol (0.079mg/mL. The profiles of each extract (fingerprint were characterized by FT–MIR spectroscopy. Conclusions The present study compares the fingerprint of different extracts of the M. sativa flowers, collected from the wild flora of Romania. The total phenolic content of the tested plant extracts was highly correlated with the radical decomposing activity. The dependence of the extract composition on the solvent polarity (acetic acid vs. methanol vs. water was revealed by UV–VIS spectrometry and Infrared fingerprint.

Comparison of ethanolamine and potassium hydroxide as quantitative trapping agents for radiolabeled CO2 in metabolism studies

International Nuclear Information System (INIS)

Medinsky, M.A.

1984-01-01

The efficiency of ethanolamine and potassium hydroxide as trapping agents for CO 2 was tested using a flow of 500 ml/min through CO 2 absorption towers containing trapping solutions. Radiolabeled CO 2 was produced by acidification of suspensions containing Ba 14 CO 3 . With 200 ml of ethanolamine, trapping efficiency of 14 CO 2 decreased when only 5% or less of the amount of ethanolamine available had reacted (22 mmoles of CO 2 trapped). In contrast, use of 200 ml of 1 M or 5 M KOH was effective in retaining 88 mmoles of CO 2 . This is equivalent to the amount of CO 2 produced by a rat over an 8-hour period

Organic solvents impair life-traits and biomarkers in the New Zealand mudsnail Potamopyrgus antipodarum (Gray) at concentrations below OECD recommendations

International Nuclear Information System (INIS)

Lecomte, V.; Noury, P.; Tutundjian, R.; Buronfosse, T.; Garric, J.; Gust, M.

2013-01-01

Highlights: •Acetone (20 μl l −1 ) accelerates embryonic development in Potamopyrgus antipodarum. •Ethanol (20 μl l −1 ) decreases growth in juvenile mudsnails. •Acetone, ethanol, methanol and DMSO increase E2 levels in snails. •Carrier solvents impair gene expression. •DMSO is to be preferred. -- Abstract: Potamopyrgus antipodarum is a gastropod mollusk proposed for use in the development of reproduction tests within the Organization for Economic Cooperation and Development (OECD). Numerous chemicals, including endocrine disrupters, are relatively water-insoluble, and water-miscible solvents are currently used for testing them. OECD recommends a maximum concentration of 100 μl l −1 . As several studies highlighted effects of lower concentrations of solvents, this study assessed the effects of 20 μl l −1 acetone, ethanol, methanol and dimethylsulfoxide (DMSO) on juvenile and adult snails during 42 days. Ethanol decreased juvenile growth, while acetone increased the rate of embryonic development. All solvents increased estradiol-like levels in adult snails. DMSO only increased mRNA expression of vitellogenin-like gene, while acetone, ethanol and methanol decreased mRNA expression of three nuclear receptor (estrogen receptor-like, ecdysone-induced protein and chicken ovalbumin upstream promoter transcription factor) genes as well as of genes encoding proteins involved in genomic (prohibitin-2) and non-genomic (striatin) pathways of estrogens activity in vertebrates. This study highlights the confounding effects of low concentrations of solvents and recommends avoiding their use. Where solvent use is inevitable, their concentrations and type should be investigated for suitability for the measured endpoints prior to use in chemical testing strategies

Organic solvents impair life-traits and biomarkers in the New Zealand mudsnail Potamopyrgus antipodarum (Gray) at concentrations below OECD recommendations

Energy Technology Data Exchange (ETDEWEB)

Lecomte, V.; Noury, P.; Tutundjian, R. [Irstea, UR MAEP, Laboratoire d’écotoxicologie, 5 rue de la Doua, CS70077, 69626 Villeurbanne Cedex (France); Buronfosse, T. [VetAgro-Sup, Campus vétérinaire, Endocrinology Laboratory, 69280 Marcy l’Etoile (France); Garric, J. [Irstea, UR MAEP, Laboratoire d’écotoxicologie, 5 rue de la Doua, CS70077, 69626 Villeurbanne Cedex (France); Gust, M., E-mail: marion.gust@irstea.fr [Irstea, UR MAEP, Laboratoire d’écotoxicologie, 5 rue de la Doua, CS70077, 69626 Villeurbanne Cedex (France)

2013-09-15

Highlights: •Acetone (20 μl l{sup −1}) accelerates embryonic development in Potamopyrgus antipodarum. •Ethanol (20 μl l{sup −1}) decreases growth in juvenile mudsnails. •Acetone, ethanol, methanol and DMSO increase E2 levels in snails. •Carrier solvents impair gene expression. •DMSO is to be preferred. -- Abstract: Potamopyrgus antipodarum is a gastropod mollusk proposed for use in the development of reproduction tests within the Organization for Economic Cooperation and Development (OECD). Numerous chemicals, including endocrine disrupters, are relatively water-insoluble, and water-miscible solvents are currently used for testing them. OECD recommends a maximum concentration of 100 μl l{sup −1}. As several studies highlighted effects of lower concentrations of solvents, this study assessed the effects of 20 μl l{sup −1} acetone, ethanol, methanol and dimethylsulfoxide (DMSO) on juvenile and adult snails during 42 days. Ethanol decreased juvenile growth, while acetone increased the rate of embryonic development. All solvents increased estradiol-like levels in adult snails. DMSO only increased mRNA expression of vitellogenin-like gene, while acetone, ethanol and methanol decreased mRNA expression of three nuclear receptor (estrogen receptor-like, ecdysone-induced protein and chicken ovalbumin upstream promoter transcription factor) genes as well as of genes encoding proteins involved in genomic (prohibitin-2) and non-genomic (striatin) pathways of estrogens activity in vertebrates. This study highlights the confounding effects of low concentrations of solvents and recommends avoiding their use. Where solvent use is inevitable, their concentrations and type should be investigated for suitability for the measured endpoints prior to use in chemical testing strategies.

Development of dispersive liquid-liquid microextraction technique using ternary solvents mixture followed by heating for the rapid and sensitive analysis of phthalate esters and di(2-ethylhexyl) adipate.

Science.gov (United States)

Farajzadeh, Mir Ali; Khoshmaram, Leila

2015-01-30

In this study, for the first time, a dispersive liquid-liquid microextraction technique using a ternary solvent mixture is reported. In order to extract five phthalate esters and di(2-ethylhexyl) adipate with different polarities from aqueous samples, a simplex centroid experimental design method was used to select an optimal mixture of ternary solvents prior to gas chromatographyflame ionization detection. In this work, dimethyl formamide as a disperser solvent containing dichloromethane, chloroform, and carbon tetrachloride as a ternary extraction solvent mixture is injected into sample solution and a cloudy solution is formed. After centrifuging, 250μL of the obtained sedimented phase was transferred into another tube and 5μL DMF was added to it. Then, the tube was heated in a water bath at 75°C for 5min in order to evaporate the main portion of the extraction solvents. Finally, 2μL of the remained phase is injected into the separation system. Under the optimum extraction conditions, the method shows wide linear ranges and low limits of detection and quantification between 0.03-0.15 and 0.09-0.55μgL(-1), respectively. Enrichment factors and extraction recoveries are in the ranges of 980-4500 and 20-90%, respectively. The method is successfully applied in the determination of the target analytes in mineral water, soda, lemon juice, vinegar, dough, and yogurt packed in plastic packages. Copyright © 2014 Elsevier B.V. All rights reserved.

Ionic association and solvation of the ionic liquid 1-hexyl-3-methylimidazolium chloride in molecular solvents revealed by vapor pressure osmometry, conductometry, volumetry, and acoustic measurements.

Science.gov (United States)

Sadeghi, Rahmat; Ebrahimi, Nosaibah

2011-11-17

A systematic study of osmotic coefficient, conductivity, volumetric and acoustic properties of solutions of ionic liquid 1-hexyl-3-methylimidazolium chloride ([C(6)mim][Cl]) in various molecular solvents has been made at different temperatures in order to study of ionic association and solvation behavior of [C(6)mim][Cl] in different solutions. Precise measurements on electrical conductances of solutions of [C(6)mim][Cl] in water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and acetonitrile at 293.15, 298.15, and 303.15 K are reported and analyzed with Barthel's low-concentration chemical model (lcCM) to obtain the limiting molar conductivities and association constants of this ionic liquid in the investigated solvents. Strong ion pairing was found for the ionic liquid in 2-propanol, 1-butanol, and 1-propanol, whereas ion association in acetonitrile, methanol and ethanol is rather weak and in water the ionic liquid is fully dissociated. In the second part of this work, the apparent molar volumes and isentropic compressibilities of [C(6)mim][Cl] in water, methanol, ethanol, acetonitrile, 1-propanol, 2-propanol, and 1-butanol are obtained at the 288.15-313.15 K temperature range at 5 K intervals at atmospheric pressure from the precise measurements of density and sound velocity. The infinite dilution apparent molar volume and isentropic compressibility values of the free ions and ion pairs of [C(6)mim][Cl] in the investigated solvents as well as the excess molar volume of the investigated solutions are determined and their variations with temperature and type of solvents are also studied. Finally, the experimental measurements of osmotic coefficient at 318.15 K for binary solutions of [C(6)mim][Cl] in water, methanol, ethanol, 2-propanol, and acetonitrile are taken using the vapor pressure osmometry (VPO) method and from which the values of the solvent activity, vapor pressure, activity coefficients, and Gibbs free energies are calculated. The results are

Ultrathin graphene-based membrane with precise molecular sieving and ultrafast solvent permeation

Science.gov (United States)

Yang, Q.; Su, Y.; Chi, C.; Cherian, C. T.; Huang, K.; Kravets, V. G.; Wang, F. C.; Zhang, J. C.; Pratt, A.; Grigorenko, A. N.; Guinea, F.; Geim, A. K.; Nair, R. R.

2017-12-01

Graphene oxide (GO) membranes continue to attract intense interest due to their unique molecular sieving properties combined with fast permeation. However, their use is limited to aqueous solutions because GO membranes appear impermeable to organic solvents, a phenomenon not yet fully understood. Here, we report efficient and fast filtration of organic solutions through GO laminates containing smooth two-dimensional (2D) capillaries made from large (10-20 μm) flakes. Without modification of sieving characteristics, these membranes can be made exceptionally thin, down to ~10 nm, which translates into fast water and organic solvent permeation. We attribute organic solvent permeation and sieving properties to randomly distributed pinholes interconnected by short graphene channels with a width of 1 nm. With increasing membrane thickness, organic solvent permeation rates decay exponentially but water continues to permeate quickly, in agreement with previous reports. The potential of ultrathin GO laminates for organic solvent nanofiltration is demonstrated by showing >99.9% rejection of small molecular weight organic dyes dissolved in methanol. Our work significantly expands possibilities for the use of GO membranes in purification and filtration technologies.

Study on the use of solid electrodes for potentiometric titrations in non-aqueous solvents-I

International Nuclear Information System (INIS)

Fatibello Filho, O.; Carvalho, W.M. de; Capelato, M.D.; Bulhoes, L.O.S.; Almeida Neves, E.F. de

1984-01-01

Fatty acids and ethanolamines were titrated potentiometrically with tetrabutylammnonium hydroxide in methyl isobutyl ketone-isopropyl alcohol and with perchloric acid in ethanol, respectively. A study of utilization of Sb, Sn, W, PbO 2 , Ti and 316L stainless steel oxides - Ag/AgBr/Bu 4 NBr (x M)/solvent electrode systems have been investigated in comparison with the glass - Ag/AgBr/Bu 4 NBr (x M)/solvent system. The best performance was obtained using W, Sb, PbO 2 and Ti electrodes have yielded a larger potential shift than glass electrode for acid-base titration. (C.L.B.) [pt

Critical cleaning agents for Di-2-ethylhexyl sebacate.

Energy Technology Data Exchange (ETDEWEB)

Hartley, Mya; Archuleta, Kim M.

2013-08-01

It is required that Di-2-ethylhexyl Sebacate oil, also commonly known as Dioctyl Sebacate oil, be thoroughly removed from certain metals, in this case stainless steel parts with narrow, enclosed spaces. Dioctyl Sebacate oil is a synthetic oil with a low compressibility. As such, it is ideally used for high pressure calibrations. The current method to remove the Dioctyl Sebacate from stainless steel parts with narrow, enclosed spaces is a labor-intensive, multi-step process, including a detergent clean, a deionized (DI) water rinse, and several solvent rinses, to achieve a nonvolatile residue of 0.04 mg per 50 mL rinse effluent. This study was undertaken to determine a superior detergent/solvent cleaning method for the oil to reduce cleaning time and/or the amount of detergent/solvent used. It was determined that while some detergent clean the oil off the metal better than the current procedure, using only solvents obtained the best result. In addition, it can be inferred, based on elevated temperature test results, that raising the temperature of the oil-contaminated stainless steel parts to approximately 50ÀC will provide for improved cleaning efficacy.

Studies on non dispersive solvent extraction for removal of dissolved di-butyl phosphate (DBP) from aqueous medium using hollow fiber membrane contactor

International Nuclear Information System (INIS)

Singh, Suman Kumar; Bindu, M.; Tripathi, S.C.; Gandhi, P.M.

2013-01-01

PUREX process is based on the principle of mass transfer by liquid liquid dispersion. Tri-n-butyl phosphate (TBP) is universal extractant for PUREX process which is employed for reprocessing the irradiated nuclear fuels for separation and recovery of fissile and fertile materials. The multi cycle solvent extraction processes encompass continuous extraction and stripping operations that are invariably carried out in pulsed columns. The continuous exposure of organic solvent (TBP) to high acidic and radioactive medium leads to decrease the solvent extraction efficiency as it degraded to different level producing di-butyl phosphate and mono-butyl phosphate in significant quantities. Efficiency of purex process decreases as di-butyl phosphate forms aqueous soluble complexes with uranium. Removal of such dissolved DBP from aqueous medium is of direct interest in reprocessing processes as this would enable to sustain the better efficiency of the process and also control the loss of fissile and fertile materials. The non-dispersive solvent extraction is a configuration of the conventional solvent-extraction process where a microporous membrane separates both the immiscible phases, one of which impregnates the membrane, thus bringing the liquid-liquid interface to one side of the membrane. This study is a preliminary evaluation of microporous hollow fiber membrane modules for the removal of dissolved DBP from acidic medium. The performance of the proposed system can be improved by optimizing controlling parameters of the process for quantitative transport of dissolved DBP from acidic medium in the purex process context

Towards a methanol economy based on homogeneous catalysis: methanol to H2 and CO2 to methanol

DEFF Research Database (Denmark)

Alberico, E.; Nielsen, Martin

2015-01-01

The possibility to implement both the exhaustive dehydrogenation of aqueous methanol to hydrogen and CO2 and the reverse reaction, the hydrogenation of CO2 to methanol and water, may pave the way to a methanol based economy as part of a promising renewable energy system. Recently, homogeneous...

Characterization of particulate sol-gel synthesis of LiNi0.8Co0.2O2 via maleic acid assistance with different solvents

International Nuclear Information System (INIS)

Zhong, Y.D.; Zhao, X.B.; Cao, G.S.; Tu, J.P.; Zhu, T.J.

2006-01-01

Particulate sol-gel LiNi 0.8 Co 0.2 O 2 has been synthesized by a maleic-acid-assisted process using de-ionized water or ethanol as the solvent. A comparison of the effect on these two different solvents was made on the basis of thermal studies, Fourier transform infrared spectroscopy, X-ray diffraction analysis, chemical diffusion coefficients measurement, and electrochemical cyclability tests. An esterification reaction occurred on the xerogel prepared with ethanol as solvent, reducing Ni and Co from their nitrate salts. LiNi 0.8 Co 0.2 O 2 grew at the expense of Li 2 CO 3 , NiO, and CoO during calcination. Better results of capacity and cyclability were obtained in a DI-water-solvent sample associated with a larger interslab thickness between O-Li-O and lower Ni occupancy on the Li site. The activation energy for the calcinations of DI-water-solvent sample is one-half of that of the ethanol-solvent one, which could be the reason for its better properties. Chemical diffusion coefficients of Li + ion are of the same order 10 -10 cm 2 /s, is not affected by the solvents used and/or the temperature raise to 55 deg. C

Studies on the absorption of uranium and plutonium on macroporous anion-exchange resins from mixed solvent media

International Nuclear Information System (INIS)

Chetty, K.V.; Mapara, P.M.; Godbole, A.G.; Swarup, Rajendra

1995-01-01

The ion-exchange studies on uranium and plutonium using macroporous anion-exchange resins from an aqueous-organic solvent mixed media were carried out to develop a method for their separation. Out of the several water miscible organic solvents tried, methanol and acetone were found to be best suited. Distribution data for U(VI) and Pu(IV) for three macroporous resins Tulsion A-27(MP) (strong base), Amberlyst A-26(MP) (strong base) and Amberlite XE-270(MP) (weak base) as a function of (i) nitric acid concentration (ii) organic solvent concentration were obtained. Based on the data separation factors for Pu/U were calculated. Column experiments using Tulsion A-27(MP) from a synthetic feed (HNO 3 - methanol and HNO 3 - acetone) containing Pu and U in different ratios were carried out. Plutonium was recovered from the bulk of the actual solution generated during the dissolution of plutonium bearing fuels. The method has the advantage of loading plutonium from as low as 1M nitric acid in presence of methanol or acetone and could be used satisfactorily for its recovery from solutions containing plutonium and uranium. (author). 11 refs., 4 figs., 16 tabs

Kinetics of hydrogen peroxide decomposition by catalase: hydroxylic solvent effects.

Science.gov (United States)

Raducan, Adina; Cantemir, Anca Ruxandra; Puiu, Mihaela; Oancea, Dumitru

2012-11-01

The effect of water-alcohol (methanol, ethanol, propan-1-ol, propan-2-ol, ethane-1,2-diol and propane-1,2,3-triol) binary mixtures on the kinetics of hydrogen peroxide decomposition in the presence of bovine liver catalase is investigated. In all solvents, the activity of catalase is smaller than in water. The results are discussed on the basis of a simple kinetic model. The kinetic constants for product formation through enzyme-substrate complex decomposition and for inactivation of catalase are estimated. The organic solvents are characterized by several physical properties: dielectric constant (D), hydrophobicity (log P), concentration of hydroxyl groups ([OH]), polarizability (α), Kamlet-Taft parameter (β) and Kosower parameter (Z). The relationships between the initial rate, kinetic constants and medium properties are analyzed by linear and multiple linear regression.

Effect of methanol, urea, and other solutes on the action of papain

NARCIS (Netherlands)

Sluyterman, L.A.A.E.

1967-01-01

The activity of papain (EC 3.4.4.10) decreases with increasing methanol concentration. At relatively low concentrations (2–4%), methanol, a few other solvents and urea (2 M) exhibit apparently competitive inhibition. However, the extent of inhibition by methanol and urea is not the same for the two

Effect of solvent-controlled aggregation on the intrinsic emission properties of PAMAM dendrimers

International Nuclear Information System (INIS)

Jasmine, Maria J.; Kavitha, Manniledam; Prasad, Edamana

2009-01-01

Solvent-induced aggregation and its effect on the intrinsic emission properties of amine, hydroxy and carboxylate terminated, poly(amidoamine) (PAMAM) dendrimers have been investigated in glycerol, ethylene glycol, methanol, ethylene diamine and water. Altering the solvent medium induces remarkable changes in the intrinsic emission properties of the PAMAM dendrimers at identical concentration. Upon excitation at 370 nm, amine terminated PAMAM dendrimer exhibits an intense emission at 470 nm in glycerol, ethylene glycol as well as glycerol-water mixtures. Conversely, weak luminescence is observed for hydroxy and carboxylate terminated PAMAM dendrimers in the same solvent systems. When the solvent is changed to ethylene diamine, hydroxy terminated PAMAM exhibits intense blue emission at 425 nm. While the emission intensity is varied when the solvent milieu is changed, excited state lifetime values of PAMAM dendrimers remain independent of the solvent used. UV-visible absorption and dynamic light scattering (DLS) experiments confirm the formation of solvent-controlled dendrimer aggregates in the systems. Comparison of the fluorescence and DLS data reveals that the size distribution of the dendrimer aggregates in each solvent system is distinct, which control the intrinsic emission intensity from PAMAM dendrimers. The experimental results suggest that intrinsic emission intensity from PAMAM dendrimers can be regulated by proper selection of solvents at neutral conditions and room temperature

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.

Microfluidic Extraction of Biomarkers using Water as Solvent

Science.gov (United States)

Amashukeli, Xenia; Manohara, Harish; Chattopadhyay, Goutam; Mehdi, Imran

2009-01-01

A proposed device, denoted a miniature microfluidic biomarker extractor (mu-EX), would extract trace amounts of chemicals of interest from samples, such as soils and rocks. Traditionally, such extractions are performed on a large scale with hazardous organic solvents; each solvent capable of dissolving only those molecules lying within narrow ranges of specific chemical and physical characteristics that notably include volatility, electric charge, and polarity. In contrast, in the mu-EX, extractions could be performed by use of small amounts (typically between 0.1 and 100 L) of water as a universal solvent. As a rule of thumb, in order to enable solvation and extraction of molecules, it is necessary to use solvents that have polarity sufficiently close to the polarity of the target molecules. The mu-EX would make selection of specific organic solvents unnecessary, because mu-EX would exploit a unique property of liquid water: the possibility of tuning its polarity to match the polarity of organic solvents appropriate for extraction of molecules of interest. The change of the permittivity of water would be achieved by exploiting interactions between the translational states of water molecules and an imposed electromagnetic field in the frequency range of 300 to 600 GHz. On a molecular level, these interactions would result in disruption of the three-dimensional hydrogen-bonding network among liquid-water molecules and subsequent solvation and hydrolysis of target molecules. The mu-EX is expected to be an efficient means of hydrolyzing chemical bonds in complex macromolecules as well and, thus, enabling analysis of the building blocks of these complex chemical systems. The mu-EX device would include a microfluidic channel, part of which would lie within a waveguide coupled to an electronically tuned source of broad-band electromagnetic radiation in the frequency range from 300 to 600 GHz (see figure). The part of the microfluidic channel lying in the waveguide would

Thermodynamics of the Sorption of Benzimidazoles on Octadecyl Silica Gel from Water-Methanol Eluents

Science.gov (United States)

Shafigulin, R. V.; Bulanova, A. V.

2018-02-01

The standard enthalpy and entropy component of transferring benzimidazoles from water-methanol solutions to surfaces of octadecyl silica gel are determined using reversed-phase high-performance liquid chromatography (RP HPLC). The dependences between the enthalpy and polarizability of the molecules of the studied benzimidazoles, the enthalpy and the entropy factor are studied, and the influence of the quantitative composition of the water-methanol solution on the enthalpy are studied.

Solvent effects on the antioxidant capacity of lipophilic and hydrophilic antioxidants measured by CUPRAC, ABTS/persulphate and FRAP methods.

Science.gov (United States)

Celik, Saliha Esin; Ozyürek, Mustafa; Güçlü, Kubilay; Apak, Reşat

2010-06-15

Antioxidants are health beneficial compounds that can protect cells and macromolecules (e.g., fats, lipids, proteins, and DNA) from the damage of reactive oxygen species (ROS). Solvent effect is a crucial parameter on the chemical behaviour of antioxidant compounds but there has been limited information regarding its role on antioxidant capacity and its assays. Therefore, the present study was undertaken to investigate the total antioxidant capacity (TAC) of some certain lipophilic and hydrophilic antioxidants, measured in different solvent media such as ethanol (EtOH) (100%), methanol (MeOH) (100%), methanol/water (4:1, v/v), methanol/water (1:1, v/v), dichloromethane (DCM)/EtOH (9:1, v/v). The cupric reducing antioxidant capacity (CUPRAC) values of selected antioxidants were experimentally reported in this work as trolox equivalent antioxidant capacity (TEAC), and compared to those found by reference TAC assays, i.e., 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)/persulphate (ABTS/persulphate) and ferric reducing antioxidant power (FRAP) methods. The TAC values of synthetic mixtures of antioxidants were experimentally measured as trolox equivalents and compared to those theoretically found by making use of the principle of additivity of absorbances assuming no chemical interaction between the mixture constituents. Possible synergistic (e.g., BHT and BHA in DCM/EtOH) or antagonistic behaviours of these synthetic mixtures were investigated in relation to solvent selection.

Impact of swelling characteristics on the permselective properties of multi-layer composite membranes for water removal from alcohols.

Science.gov (United States)

The removal of water from organic solvents and biofuels, including lower alcohols (i.e., methanol, ethanol, propanol, and butanol), is necessary for the production, blending, and reuse of those organic compounds. Water forms an azeotrope with many hydrophilic solvents, complicati...

Copper Leaching from Copper-ethanolamine Treated Wood: Comparison of Field Test Studies and Laboratory Standard Procedures

OpenAIRE

Nejc Thaler; Miha Humar

2014-01-01

Copper-based compounds are some of the most important biocides for the protection of wood in heavy duty applications. In the past, copper was combined with chromium compounds to reduce copper leaching, but a recent generation of copper-based preservatives uses ethanolamine as a fixative. To elucidate the leaching of copper biocides from wood, Norway spruce (Picea abies) wood was treated with a commercial copper-ethanolamine solution with two different copper concentrations (cCu = 0.125% and 0...

Measurement and correlation of the solubility of (1-benzyl-1H-1,2,3-triazole-4-yl)methanol in water and alcohols at temperatures from 292.15 K to 310.15 K

Energy Technology Data Exchange (ETDEWEB)

Liang, Shuqin [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, Henan 450001 (China); Li, Huiying [China Certification & Inspection (Group) Henan Co., Ltd., Zhengzhou, Henan 450000 (China); Shen, Le; Li, Huanxin; Mao, Zhendong [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, Henan 450001 (China); Li, Huiping, E-mail: huipingli@zzu.edu.cn [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, Henan 450001 (China)

2016-04-20

Highlights: • The (1-benzyl-1H-1,2,3-triazole-4-yl) methanol was successfully synthesized and characterized by IR and NMR. • The solubilities of (1-benzyl-1H-1,2,3-triazole-4-yl) methanol in water and alcohols were measured. • The experimental solubility data were correlated with the Van’t Hoff equation, modified Apelblat equation and λh equation model. • The dissolution enthalpy of (1-benzyl-1H-1,2,3-triazole-4-yl) methanol was calculated by using the modified Apelblat equation. • The solubility data, correlation models, and the thermodynamic parameters were discussed in detail. - Abstract: The solubilities of (1-benzyl-1H-1,2,3-triazole-4-yl)methanol (BTZM) in water, methanol, ethanol, n-propanol, isopropanol, and n-butanol were measured at temperatures ranging from 292.15 K to 310.15 K by a dynamic method under normal atmospheric pressure. The results showed that it increased with the increasing temperature and the order of solvents was: order: methanol > ethanol > n-propanol > n-butanol > isopropanol > water except three points. The solubility data were correlated with the Van’t Hoff equation, modified Apelblat equation, and λh equation. The average relative deviations (ARD) were 1.87%, 1.53%, and 1.71%, and the root-mean-square-deviations (RMSD) were 2.37 × 10{sup −2}, 1.51 × 10{sup −2}, and 2.12 × 10{sup −2}, respectively. It was found that the modified Apelblat equation gave the best correlation results. Furthermore, the dissolution enthalpy of BTZM was calculated by the modified Apelblat equation.

Substantial rate enhancements of the esterification reaction of phthalic anhydride with methanol at high pressure and using supercritical CO2 as a co-solvent in a glass microreactor

NARCIS (Netherlands)

Benito-Lopez, F.; Tiggelaar, Roald M.; Salblut, K.; Huskens, Jurriaan; Egberink, Richard J.M.; Reinhoudt, David; Gardeniers, Johannes G.E.; Verboom, Willem

2007-01-01

The esterification reaction of phthalic anhydride with methanol was performed at different temperatures in a continuous flow glass microreactor at pressures up to 110 bar and using supercritical CO2 as a co-solvent. The design is such that supercritical CO2 can be generated inside the microreactor.

A Four-Site Molecular Model for Simulations of Liquid Methanol and Water-Methanol Mixtures: MeOH-4P.

Science.gov (United States)

Martínez-Jiménez, Manuel; Saint-Martin, Humberto

2018-04-17

In this work, we present a new four-site potential for methanol, MeOH-4P, fitted to reproduce the dielectric constant ε, the surface tension γ s , and the liquid density ρ of the pure liquid at T = 298.15 K and p = 1 bar. The partial charges on each site were taken from the OPLS/2016 model with the only difference of putting the negative charge on the fourth site ( M) instead of on the O atom, as done in four-site water models. The original Lennard-Jones (LJ) parameters of OPLS/2016 for the methyl moiety (Me) were modified for the fitting of ρ and γ s , whereas the parameters of the TIP4P-FB water model were used for the O atom without change. Taking into account the energetic cost of the enhanced dipole relative to the isolated molecule, the results from simulations with this model showed good agreement with experiments for ρ, α p , κ T , C p , and Δ H v- l . Also, the temperature dependence of γ s and ε is satisfactory in the interval between 260 and 360 K, and the critical point description is similar to that of OPLS/2016. It is shown that orientational correlations, described by the Kirkwood factor G k , play a prominent role in the appropriate description of dielectric constants in existing models; unfortunately, the enhancement of the dipole moment produced a low diffusion coefficient D MeOH ; thus, a compromise was required between a good reproduction of ε and an acceptable D MeOH . The use of a fourth site resulted in a significant improvement for water-methanol mixtures described with TIP4P-FB and MeOH-4P, respectively, but required the modification of the LJ geometric combination rule to allow a good description of the methanol molar-fraction dependence of ρ, ε, and methanol (water) diffusion coefficients D MeOH ( D H 2 O ) and excess volume of mixing Δ V mix in the entire range of composition. The resulting free energy of hydration Δ G hyd shows excellent agreement with experiments in the interval between 280 and 360 K.

Necrosis and haemorrhage of the putamen in methanol poisoning shown on MRI

International Nuclear Information System (INIS)

Kuteifan, K.; Gutbub, A.M.; Laplatte, G.; Oesterle, H.; Tajahmady, T.

1998-01-01

Methanol, a highly toxic substance, is used as an industrial solvent and in automobile antifreeze. Acute methanol poisoning produces severe metabolic acidosis and serious neurologic sequelae. We describe a 50-year-old woman with accidental methanol intoxication who was in a vegetative state. MRI showed haemorrhagic necrosis of the putamina and oedema in the deep white matter. (orig.)

Influences of surface and solvent on retention of HEMA/mixture components after evaporation.

Science.gov (United States)

Garcia, Fernanda C P; Wang, Linda; Pereira, Lúcia C G; de Andrade e Silva, Safira M; Júnior, Luiz M; Carrilho, Marcela Rocha de Oliveira

2010-01-01

This study examined the retention of solvents within experimental HEMA/solvent primers after two conditions for solvent evaporation: from a free surface or from dentine surface. Experimental primers were prepared by mixing 35% HEMA with 65% water, methanol, ethanol or acetone (v/v). Aliquots of each primer (50 microl) were placed on glass wells or they were applied to the surface of acid-etched dentine cubes (2mm x 2mm x 2mm) (n=5). For both conditions (i.e. from free surface or dentine cubes), change in primers mass due to solvent evaporation was gravimetrically measured for 10min at 51% RH and 21 degrees C. The rate of solvent evaporation was calculated as a function of loss of primers mass (%) over time. Data were analysed by two-way ANOVA and Student-Newman-Keuls (pevaporation rate (%/min) depending on the solvent present in the primer and the condition for evaporation (from free surface or dentine cubes) (pevaporation for HEMA/acetone primer was almost 2- to 10-times higher than for HEMA/water primer depending whether evaporation occurred, respectively, from a free surface or dentine cubes. The rate of solvent evaporation varied with time, being in general highest at the earliest periods. The rate of solvent evaporation and its retention into HEMA/solvent primers was influenced by the type of the solvent and condition allowed for their evaporation.

Thermodynamics of the second-stage dissociation of 2-[N-(2-hydroxyethyl)-N-methylaminomethyl]-propenoic acid (HEMPA) in water at different ionic strength and different solvent mixtures

International Nuclear Information System (INIS)

Taha, Mohamed; Fazary, Ahmed E.

2005-01-01

The second stage dissociation constant pK 2 of 2-[N-(2-hydroxyethyl)-N-methylaminomethyl]-propenoic acid (HEMPA) has been determined in aqueous solution at different ionic strengths and different temperatures, using pH-metric technique. The thermodynamic quantities (ΔG 0 , ΔH 0 , and ΔS 0 ) have been studied and discussed. Evaluation of the effect of organic solvent of the medium on the dissociation processes have also been reported and discussed. The organic solvents used were methanol, dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetone and dioxane. The pK 2 for the ionization in water +10, +20, +30, +40 and +50 wt% dioxane has been determined at five different temperatures from T = (288.15 to 308.15) K at intervals of 5 K. The thermodynamic quantities were calculated. The implications of the results with regard to specific (solute + solvent) interactions (particularly stabilization of zwitterionic species) are also discussed

Why does high pressure destroy co-non-solvency of PNIPAm in aqueous methanol?

OpenAIRE

de Oliveira, Tiago E.; Netz, Paulo A.; Mukherji, Debashish; Kremer, Kurt

2016-01-01

It is well known that poly(N-isopropylacrylamide) (PNIPAm) exhibits an interesting, yet puzzling, phenomenon of co-non-solvency. Co-non-solvency occurs when two competing good solvents for PNIPAm, such as water and alcohol, are mixed together. As a result, the same PNIPAm collapses within intermediate mixing ratios. This complex conformational transition is driven by preferential binding of methanol with PNIPAm. Interestingly, co-non-solvency can be destroyed when applying high hydrostatic pr...

Oxidation of Glycerol and Propanediols in Methanol over Heterogeneous Gold Catalysts

DEFF Research Database (Denmark)

Taarning, Esben; Madsen, Anders Theilgaard; Marchetti, Jorge

2008-01-01

Aerobic oxidation of glycerol over metal oxide supported gold nanoparticles in methanol results in the formation of dimethyl mesoxalate in selectivities up to 89% at full conversion. The oxidative esterification takes place in methanol, acting both as solvent and reactant, and in the presence of ...

PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol Steam Reforming, and Reverse-Water-Gas-Shift

Energy Technology Data Exchange (ETDEWEB)

Dagle, Robert A.; Platon, Alexandru; Datye, Abhaya K.; Vohs, John M.; Wang, Yong; Palo, Daniel R.

2008-03-07

Pd/ZnO/Al2O3 catalysts were studied for water-gas-shift (WGS), methanol steam reforming, and reverse-water-gas-shift (RWGS) reactions. WGS activity was found to be dependent on the Pd:Zn ratio with a maximum activity obtained at approximately 0.50, which was comparable to that of a commercial Pt-based catalyst. The catalyst stability was demonstrated for 100 hours time-on-stream at a temperature of 3600C without evidence of metal sintering. WGS reaction rates were approximately 1st order with respect to CO concentration, and kinetic parameters were determined to be Ea = 58.3 kJ mol-1 and k0 = 6.1x107 min-1. During methanol steam reforming, the CO selectivities were observed to be lower than the calculated equilibrium values over a range of temperatures and steam/carbon ratios studied while the reaction rate constants were approximately of the same magnitude for both WGS and methanol steam reforming. These results indicate that although Pd/ZnO/Al2O3 are active WGS catalysts, WGS is not involved in methanol steam reforming. RWGS rate constants are on the order of about 20 times lower than that of methanol steam reforming, suggesting that RWGS reaction could be one of the sources for small amount of CO formation in methanol steam reforming.

Preliminary structural investigations of the Eut-L shell protein of the ethanolamine ammonia-lyase metabolosome of Escherichia coli

International Nuclear Information System (INIS)

Nikolakakis, Kiel; Ohtaki, Akashi; Newton, Keith; Chworos, Arkadiusz; Sagermann, Martin

2009-01-01

Preliminary X-ray analysis of crystals of the bacterial microcompartment shell protein Eut-L from Escherichia coli is reported. The ethanolamine ammonia-lyase microcompartment is composed of five different shell proteins that have been proposed to assemble into symmetrically shaped polyhedral particles of varying sizes. Here, preliminary X-ray analysis of crystals of the bacterial microcompartment shell protein Eut-L from Escherichia coli is reported. Cloning, overexpression and purification resulted in highly pure protein that crystallized readily under many different conditions. In all cases the protein forms thin hexagonal plate-shaped crystals belonging to space group P3 that are of unusually high stability against different solvent conditions. The crystals diffracted to a resolution of 2.0 Å using synchrotron radiation but proved to be radiation-sensitive. Preparations of heavy-atom-derivatized crystals for use in determining the three-dimensional structure are under way

Study on separation of methanol-butyl methylether-1-chlorobutane system

International Nuclear Information System (INIS)

Zhang Weijiang; Cao Tianhong

2006-01-01

The separation of mixture plays an important role in chemical, petrochemical, medical biochemical industries and environmental protection engineering. Liquid mixture with azeotropic phenomenon cannot be separated by conventional distillation as well as extractive distillation. But the combination of extraction and distillation can be effective for them. This paper includes many experiments with the ternary mixture of methanol butyl methyl ether and 1-chlorobytane, which shows that the system is not ternary azeotrope and can be separated by the combination of extraction and rectification using water as extractive solvent. (authors)

Cogeneration of biodiesel and nontoxic cottonseed meal from cottonseed processed by two-phase solvent extraction

Energy Technology Data Exchange (ETDEWEB)

Qian Junfeng, E-mail: qianjunfeng80@126.co [Jiangsu Provincial Key Laboratory of Fine Petrochemical Engineering, Jiangsu Polytechnic University, Changzhou 213016 (China) and College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China); Yun Zhi; Shi Haixian [College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China)

2010-12-15

In the present work, the preparation of biodiesel from cottonseed oil produced by two-phase solvent extraction (TSE) was studied. The experimental results of TSE process of cottonseed showed that the optimal extraction conditions were 30 g samples, 240 mL extraction solvent mixture and methanol/petroleum ether volume ratio 60:40, extraction temperature 30 deg. C, extraction time 30 min. Under the extraction conditions, the extraction rate of cottonseed oil could achieve 98.3%, the free fatty acid (FFA) and water contents of cottonseed oil were reduced to 0.20% and 0.037%, respectively, which met the requirement of alkali-catalyzed transesterification. The free gossypol (FG) content in cottonseed meal produced from two-phase solvent extraction could reduce to 0.014% which was far below the FAO standard. And the nontoxic cottonseed meal could be used as animal protein feed resources. After the TSE process of cottonseed, the investigations were carried out on transesterification of methanol with oil-petroleum ether solution coming from TSE process in the presence of sodium hydroxide (CaO) as the solid base catalyst. The influences of weight ratio of petroleum ether to cottonseed oil, reaction temperature, molar ratio of methanol to oil, alkali catalyst amount and reaction time on cottonseed oil conversion were respectively investigated by mono-factor experiments. The conversion of cottonseed oil into fatty acid methyl ester (FAME) could achieve 98.6% with 3:1 petroleum ether/oil weight ratio, 65 deg. C reaction temperature, 9:1 methanol/oil mole ratio, 4% (catalyst/oil weight ratio, w/w) solid base catalyst amount and 3 h reaction time. The properties of FAME product prepared from cottonseed oil produced by two-phase solvent extraction met the ASTM specifications for biodiesel.

Cogeneration of biodiesel and nontoxic cottonseed meal from cottonseed processed by two-phase solvent extraction

Energy Technology Data Exchange (ETDEWEB)

Qian, Junfeng [Jiangsu Provincial Key Laboratory of Fine Petrochemical Engineering, Jiangsu Polytechnic University, Changzhou 213016 (China); College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China); Yun, Zhi; Shi, Haixian [College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China)

2010-12-15

In the present work, the preparation of biodiesel from cottonseed oil produced by two-phase solvent extraction (TSE) was studied. The experimental results of TSE process of cottonseed showed that the optimal extraction conditions were 30 g samples, 240 mL extraction solvent mixture and methanol/petroleum ether volume ratio 60:40, extraction temperature 30 C, extraction time 30 min. Under the extraction conditions, the extraction rate of cottonseed oil could achieve 98.3%, the free fatty acid (FFA) and water contents of cottonseed oil were reduced to 0.20% and 0.037%, respectively, which met the requirement of alkali-catalyzed transesterification. The free gossypol (FG) content in cottonseed meal produced from two-phase solvent extraction could reduce to 0.014% which was far below the FAO standard. And the nontoxic cottonseed meal could be used as animal protein feed resources. After the TSE process of cottonseed, the investigations were carried out on transesterification of methanol with oil-petroleum ether solution coming from TSE process in the presence of sodium hydroxide (CaO) as the solid base catalyst. The influences of weight ratio of petroleum ether to cottonseed oil, reaction temperature, molar ratio of methanol to oil, alkali catalyst amount and reaction time on cottonseed oil conversion were respectively investigated by mono-factor experiments. The conversion of cottonseed oil into fatty acid methyl ester (FAME) could achieve 98.6% with 3:1 petroleum ether/oil weight ratio, 65 C reaction temperature, 9:1 methanol/oil mole ratio, 4% (catalyst/oil weight ratio, w/w) solid base catalyst amount and 3 h reaction time. The properties of FAME product prepared from cottonseed oil produced by two-phase solvent extraction met the ASTM specifications for biodiesel. (author)

Technoeconomic analysis of a methanol plant based on gasification of biomass and electrolysis of water

DEFF Research Database (Denmark)

Clausen, Lasse Røngaard; Houbak, N.; Elmegaard, Brian

2010-01-01

, and the low-temperature waste heat is used for district heat production. This results in high total energy efficiencies (similar to 90%) for the plants. The specific methanol costs for the six plants are in the range 11.8-25.3 (sic)/GJ(exergy). The lowest cost is obtained by a plant using electrolysis......Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO2...... with a different syngas production method, were compared. The plants achieve methanol exergy efficiencies of 59-72%, the best from a configuration incorporating autothermal reforming of biogas and electrolysis of water for syngas production. The different processes in the plants are highly heat integrated...

Evaluation of the antidiarrhoeal activity of 80% methanol extract and ...

African Journals Online (AJOL)

Lantana camara L. is one of the medicinal plants traditionally used for the treatment of diarrhoea in Ethiopia. The aim of this study was to evaluate antidiarrhoeal activity of the 80% methanol extract and solvent fractions using mice model of diarrhoea. The 80% methanol extract was prepared by maceration and the fractions ...

Chetoui olive leaf extracts: influence of the solvent type on the phenolics and antioxidant activities

Energy Technology Data Exchange (ETDEWEB)

Abaza, L.; Ben Youssef, N.; Manai, H.; Haddada, F.M.; Methenni, K.; Zarrouk, M.

2011-07-01

The aim of this study was to investigate the influence of the solvent type on the extraction of phenolics and the antioxidant properties of the extracts obtained from Chetoui olive leaves. Extraction was conducted at room temperature using four solvents: deionized water (ddH2O), 80% methanol (80% MeOH), 70% ethanol (70% EtOH), and 80% acetone. Total phenols and total flavonoids were measured using the Folin-Ciocalteau and aluminum chloride colorimetric methods, respectively. The antioxidant properties have been determined by two scavenging activity methods, DPPH and ABTS. (Author).

Prednisolone multicomponent nanoparticle preparation by aerosol solvent extraction system.

Science.gov (United States)

Moribe, Kunikazu; Fukino, Mika; Tozuka, Yuichi; Higashi, Kenjirou; Yamamoto, Keiji

2009-10-01

Prednisolone nanoparticles were prepared in the presence of a hydrophilic polymer and a surfactant by the aerosol solvent extraction system (ASES). A ternary mixture of prednisolone, polyethylene glycol (PEG), and sodium dodecyl sulfate (SDS) dissolved in methanol was sprayed through a nozzle into the reaction vessel filled with supercritical carbon dioxide. After the ASES process was repeated, precipitates of the ternary components were obtained by depressurizing the reaction vessel. When a methanolic solution of prednisolone/PEG 4000/SDS at a weight ratio of 1:6:2 was sprayed under the optimized ASES conditions, the mean particle size of prednisolone obtained after dispersing the precipitates in water was observed to be ca. 230 nm. Prednisolone nanoparticles were not obtained by the binary ASES process for prednisolone, in the presence of either PEG or SDS. Furthermore, ternary cryogenic cogrinding, as well as solvent evaporation, was not effective for the preparation of prednisolone nanoparticles. As the ASES process can be conducted under moderate temperature conditions, the ASES process that was applied to the ternary system appeared to be one of the most promising methods for the preparation of drug nanoparticles using the multicomponent system.

Molar extinction coefficients of some commonly used solvents

International Nuclear Information System (INIS)

Kumar, Ashok; Singh, Sukhpal; Singh Mudahar, Gurmel; Singh Thind, Kulwant

2006-01-01

Molar extinction coefficients of some commonly used solvents (ethanol (C 2 H 5 OH), methanol (CH 3 OH), propanol (C 3 H 7 OH), butanol (C 4 H 9 OH), water (H 2 O), toluene (C 7 H 8 ), benzene (C 6 H 6 ), carbontetrachloride (CCl 4 ), acetonitrile (C 4 H 3 N), chlorobenzene (C 6 H 5 Cl), diethylether (C 4 H 1 O) and dioxane (C 4 H 8 O 2 )) have been determined by a well-collimated narrow beam transmission geometry at 279, 356, 662, 1173, 1252 and 1332 keV γ rays. The total γ ray interaction cross sections of these solvents have also been determined. A good agreement has been obtained between the experimental results with the theoretical values evaluated through XCOM calculations

Thermodynamic properties of solutions of sodium di-hydrogen phosphate in (1-propanol + water) mixed-solvent media over the temperature range of (283.15 to 303.15) K

International Nuclear Information System (INIS)

Sadeghi, Rahmat; Parhizkar, Hana

2008-01-01

The apparent molar volume and apparent molar isentropic compressibility of solutions of sodium di-hydrogen phosphate (NaH 2 PO 4 ) in (1-propanol + water) mixed-solvent media with alcohol mass fractions of 0.00, 0.05, 0.10, and 0.15 are reported over the range of temperature (283.15 to 303.15) K at 5 K intervals. The results were fitted to a Redlich-Mayer type equation from which the apparent molar volume and apparent molar isentropic compressibility of the solutions at the infinite dilution were also calculated at the working temperature. The results show a positive transfer volume of NaH 2 PO 4 from an aqueous solution to an aqueous 1-propanol solution. The apparent molar isentropic compressibility of NaH 2 PO 4 in aqueous 1-propanol solutions is negative and it increases with increasing the concentration of NaH 2 PO 4 , 1-propanol, and temperature. Electrical conductivity and refractive index of the solutions are also studied at T = 298.15 K. The effects of the electrolyte concentration and relative permittivity of the medium on the molar conductivity were also investigated

Flow and heat transfer thermohydraulic modelisation during the reflooding phase of a P.W.R.'s core

International Nuclear Information System (INIS)

Raymond, Patrick

1978-04-01

Some generalities about L.O.C.A. are first recalled. The French experimental studies about Emergency Core Cooling System are briefly described. The different heat transfer mechanisms to take into account, according to the flow pattern in the dry zone, and the correlations or methods to calculate them, are defined. Then the Thermohydraulic code computer: FLIRA, which describe the reflooding phase, and a modelisation taking into account the different flow patterns are setted. A first interpretation of ERSEC experiments with a tubular test section shows that it is possible, with this modelisation and some classical heat transfer correlations, to describe the reflooding phase. [fr

NMR investigation and theoretical calculations of the effect of solvent on the conformational analysis of 4',7-di-hydroxy-8-prenylflavan

Directory of Open Access Journals (Sweden)

Alcântara Antônio Flávio de Carvalho

2004-01-01

Full Text Available The NMR conformational study of 4',7-di-hydroxy-8-prenylflavan 1 was carried out in acetone-d6, DMSO-d6 and CDCl3 which enabled the proposition of three conformations, namely 1a, 1b and 1c, differing in the position of the prenyl group. Geometry optimizations performed using AM1 method showed that 1a (deltaHf = -86.2 kcal/mol is as stable as 1b (deltaHf = -85.1 kcal/mol and 1c (deltaHf = -85.4 kcal/mol. When the solvent was included, the calculations showed that the solute-solvent interactions could be explained either in the light of the electronic intermolecular delocalization or the electrostatic character between solute and solvent. Theoretical calculations (HF/6-31G*, deltaFT/BLYP/6-31G*, and deltaFT/B3LYP/6-31G* showed that the combination of these types of interactions present in each solute-solvent system, dependent on the chemical properties of the solvent, lead to different spatial arrangements of the prenyl group, which in turn determined the conformation of 1.

Investigating the effects of methanol-water vapor mixture on a PBI-based high temperature PEM fuel cell

DEFF Research Database (Denmark)

Araya, Samuel Simon; Andreasen, Søren Juhl; Nielsen, Heidi Venstrup

2012-01-01

This paper investigates the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC). A H3PO4-doped polybenzimidazole (PBI) membrane electrode assembly (MEA), Celtec P2100 of 45 cm2 of active surface area from BASF was employed....... A long-term durability test of around 1250 h was performed, in which the concentrations of methanol-water vapor mixture in the anode feed gas were varied. The fuel cell showed a continuous performance decay in the presence of vapor mixtures of methanol and water of 5% and 8% by volume in anode feed...

Transesterification of triacetin, tributyrin, and soybean oil with methanol over hydrotalcites with different water contents

Energy Technology Data Exchange (ETDEWEB)

Kim, Mi Jin; Park, Se Min; Seo, Gon [School of Applied Chemical Engineering and the Research Institute for Catalysis, Chonnam National University, Yungbong-Dong, Buk-Gu, Gwangju 500-757 (Korea); Chang, Duck Rae [Korea Institute of Industrial Technology, 1110-9 Oryoung-Dong, Buk-Gu, Gwangju 500-480 (Korea)

2010-06-15

Transesterification of triacetin, tributyrin and soybean oil with methanol was examined over rehydrated hydrotalcites (HT-reh), which were previously calcined at 550 C and exposed to an ambient atmosphere, in order to investigate the effect of the water content on their catalytic activity. Rehydration of a calcined hydrotalcite at 25 C produced uniform mesopores of around 4 nm diameter, while the removal of water from the HT-reh by pretreatment at 500 C, formed large heterogeneous mesopores. Methanol was adsorbed and desorbed rapidly in the mesopores of the HT-reh filled with water. The pretreatment of the HT-reh at 500 C removed both water and carbon dioxide, producing strong basic sites. The high activity of fully rehydrated hydrotalcite in the transesterification of three triglycerides was explained by the generation of Broensted basic sites and the rapid migration of methanol in the mesopores, while the improved activity of the rehydrated hydrotalcite pretreated at 500 C by the generation of strong basic sites and empty mesopores due to the removal of water and carbon dioxide. (author)

Ground observations and remote sensing data for integrated modelisation of water budget in the Merguellil catchment, Tunisia

Science.gov (United States)

Mougenot, Bernard

2016-04-01

The Mediterranean region is affected by water scarcity. Some countries as Tunisia reached the limit of 550 m3/year/capita due overexploitation of low water resources for irrigation, domestic uses and industry. A lot of programs aim to evaluate strategies to improve water consumption at regional level. In central Tunisia, on the Merguellil catchment, we develop integrated water resources modelisations based on social investigations, ground observations and remote sensing data. The main objective is to close the water budget at regional level and to estimate irrigation and water pumping to test scenarios with endusers. Our works benefit from French, bilateral and European projects (ANR, MISTRALS/SICMed, FP6, FP7…), GMES/GEOLAND-ESA) and also network projects as JECAM and AERONET, where the Merguellil site is a reference. This site has specific characteristics associating irrigated and rainfed crops mixing cereals, market gardening and orchards and will be proposed as a new environmental observing system connected to the OMERE, TENSIFT and OSR systems respectively in Tunisia, Morocco and France. We show here an original and large set of ground and remote sensing data mainly acquired from 2008 to present to be used for calibration/validation of water budget processes and integrated models for present and scenarios: - Ground data: meteorological stations, water budget at local scale: fluxes tower, soil fluxes, soil and surface temperature, soil moisture, drainage, flow, water level in lakes, aquifer, vegetation parameters on selected fieds/month (LAI, height, biomass, yield), land cover: 3 times/year, bare soil roughness, irrigation and pumping estimations, soil texture. - Remote sensing data: remote sensing products from multi-platform (MODIS, SPOT, LANDSAT, ASTER, PLEIADES, ASAR, COSMO-SkyMed, TerraSAR X…), multi-wavelength (solar, micro-wave and thermal) and multi-resolution (0.5 meters to 1 km). Ground observations are used (1) to calibrate soil

Thermodynamics of the second-stage dissociation of 2-[N-(2-hydroxyethyl)-N-methylaminomethyl]-propenoic acid (HEMPA) in water at different ionic strength and different solvent mixtures

Energy Technology Data Exchange (ETDEWEB)

Taha, Mohamed [Department of Chemistry, Faculty of Science, Cairo University, Beni-Suef Branch, Beni-Suef (Egypt)]. E-mail: mtaha978@yahoo.com; Fazary, Ahmed E. [Department of Chemistry, Faculty of Science, Cairo University, Beni-Suef Branch, Beni-Suef (Egypt)

2005-01-01

The second stage dissociation constant pK{sub 2} of 2-[N-(2-hydroxyethyl)-N-methylaminomethyl]-propenoic acid (HEMPA) has been determined in aqueous solution at different ionic strengths and different temperatures, using pH-metric technique. The thermodynamic quantities ({delta}G{sup 0}, {delta}H{sup 0}, and {delta}S{sup 0}) have been studied and discussed. Evaluation of the effect of organic solvent of the medium on the dissociation processes have also been reported and discussed. The organic solvents used were methanol, dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetone and dioxane. The pK{sub 2} for the ionization in water +10, +20, +30, +40 and +50 wt% dioxane has been determined at five different temperatures from T = (288.15 to 308.15) K at intervals of 5 K. The thermodynamic quantities were calculated. The implications of the results with regard to specific (solute + solvent) interactions (particularly stabilization of zwitterionic species) are also discussed.

Influence of polyvinylpyrrolidone on the interaction between water and methanol

Directory of Open Access Journals (Sweden)

M. Guettari

2013-09-01

Full Text Available The present work aims to determine the influence of a dissolved polymer, polyvinylpyrrolidone, on the interaction between water and methanol. First, the dynamic viscosities were measured for polymer solutions by a rotational concentric cylinder at 25 ºC and for the polymer concentration range from 0.1 to 0.6 g/dl. The results show a polynomial dependence of the viscosity on polymer concentration. On the hypothesis of a quasi-binary system, a pseudo Grumberg-Nissan constant, d'p, was introduced to quantify the interaction between unlike molecules in the presence of polymer. The interaction between unlike molecules due to the presence of the polymer was quantified by the deviation of the Grumberg-Nissan constant, δd'p= d p. Generally, this constant is negative which means that the interactions between water and methanol decrease in the presence of polyvinylpyrrolidone at 25 ºC. The presence of the polymer induces a perturbation of the dynamic equilibrium between free and complexed molecules

Age dependent accumulation of N-acyl-ethanolamine phospholipids in ischemic rat brain

DEFF Research Database (Denmark)

Moesgaard, B.; Petersen, G.; Hansen, Harald S.

2000-01-01

N-acyl-ethanolamine phospholipids (NAPE) can be formed as a stress response during neuronal injury, and they are precursors for N-acyl- ethanolamines (NAE), some of which are endocannabinoids. The levels of NAPE accumulated during post-decapitative ischemia (6 h at 37°C) were studied in rat brains...... of various age (1, 6, 12, 19, 30, and ~70 days) by the use of P NMR spectroscopy of lipid extracts. This ability to accumulate NAPE was compared with the activity of N-acyltransferase and of NAPE-hydrolyzing phospholipase D (NAPE-PLD) in brain microsomes. These two enzymes are involved in the formation...... brains NAPE accumulation could not be detected (detection limit 0.09 %)]; and 2) this age pattern of accumulation can be explained by a combination of the decreased activity of N- acyltransferase and the increased activity of NAPE-PLD during development. These results point out that it would...

Measurement and correlation of solubility of trans-resveratrol in 11 solvents at T = (278.2, 288.2, 298.2, 308.2, and 318.2) K

Energy Technology Data Exchange (ETDEWEB)

Sun Xilan; Peng Bin [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Yan Weidong [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China)], E-mail: yanweidong@zju.edu.cn

2008-04-15

The solubilities of trans-resveratrol in methanol, ethanol, 1-propanol, 2- propanol, 1-butanol, 1-pentanol, 1-hexanol, ethyl acetate, tetrahydrofuran, acetone, and water (pH 6.0) solvents were measured at T = (278.2, 288.2, 298.2, 308.2, and 318.2) K. The solubilities of trans-resveratrol in selected solvents increase with temperature, but decrease with increasing the number of carbon in alcohol solvents. The experimental data were correlated using a thermodynamic equation.

Measurement and correlation of solubility of trans-resveratrol in 11 solvents at T = (278.2, 288.2, 298.2, 308.2, and 318.2) K

International Nuclear Information System (INIS)

Sun Xilan; Peng Bin; Yan Weidong

2008-01-01

The solubilities of trans-resveratrol in methanol, ethanol, 1-propanol, 2- propanol, 1-butanol, 1-pentanol, 1-hexanol, ethyl acetate, tetrahydrofuran, acetone, and water (pH 6.0) solvents were measured at T = (278.2, 288.2, 298.2, 308.2, and 318.2) K. The solubilities of trans-resveratrol in selected solvents increase with temperature, but decrease with increasing the number of carbon in alcohol solvents. The experimental data were correlated using a thermodynamic equation

Computing pKa Values in Different Solvents by Electrostatic Transformation.

Science.gov (United States)

Rossini, Emanuele; Netz, Roland R; Knapp, Ernst-Walter

2016-07-12

We introduce a method that requires only moderate computational effort to compute pKa values of small molecules in different solvents with an average accuracy of better than 0.7 pH units. With a known pKa value in one solvent, the electrostatic transform method computes the pKa value in any other solvent if the proton solvation energy is known in both considered solvents. To apply the electrostatic transform method to a molecule, the electrostatic solvation energies of the protonated and deprotonated molecular species are computed in the two considered solvents using a dielectric continuum to describe the solvent. This is demonstrated for 30 molecules belonging to 10 different molecular families by considering 77 measured pKa values in 4 different solvents: water, acetonitrile, dimethyl sulfoxide, and methanol. The electrostatic transform method can be applied to any other solvent if the proton solvation energy is known. It is exclusively based on physicochemical principles, not using any empirical fetch factors or explicit solvent molecules, to obtain agreement with measured pKa values and is therefore ready to be generalized to other solute molecules and solvents. From the computed pKa values, we obtained relative proton solvation energies, which agree very well with the proton solvation energies computed recently by ab initio methods, and used these energies in the present study.

Biodiesel production via injection of superheated methanol technology at atmospheric pressure

International Nuclear Information System (INIS)

Ang, Gaik Tin; Tan, Kok Tat; Lee, Keat Teong; Mohamed, Abdul Rahman

2014-01-01

Highlights: • Non-catalytic superheated methanol for biodiesel production is developed. • Crude Jatropha curcas oil with high FFA can be directly used as oil feedstock. • High content of biodiesel can be produced. • Separation of FAME and glycerol from the sample product is easy. - Abstract: In this high demand of renewable energy market, biodiesel was extensively produced via various catalytic and non-catalytic technologies. Conventional catalytic transesterification for biodiesel production has been shown to have limitation in terms of sensitivity to high water and free fatty acid, complicated separation and purification of biodiesel. In this study, an alternative and innovative approach was carried out via non-catalytic superheated methanol technology to produce biodiesel. Similar to supercritical reaction, the solvent need to be heated beyond the critical temperature but the reactor pressure remained at 0.1 MPa (atmospheric pressure). Transesterification reaction with superheated methanol was carried out at different reaction temperature within the limit of 270–300 °C and at different methanol flow rate ranging from 1 ml/min to 3 ml/min for 4 h. Results obtained showed that the highest biodiesel yield at 71.54% w/w was achieved at reaction temperature 290 °C and methanol flow rate at 2 ml/min with 88.81% w/w FAME content, implying the huge potential of superheated technology in producing FAME

Solvent Flux Method (SFM): A Case Study of Water Access to Candida antarctica Lipase B.

Science.gov (United States)

Benson, Sven P; Pleiss, Jürgen

2014-11-11

The solvent flux method (SFM) was developed to comprehensively characterize the influx of solvent molecules from the solvent environment into the active site of a protein in the framework of molecular dynamics simulations. This was achieved by introducing a solvent concentration gradient as well as partially reorienting and rescaling the velocity vector of all solvent molecules contained within a spherical volume enclosing the protein, thus inducing an accelerated solvent influx toward the active site. In addition to the detection of solvent access pathway within the protein structure, it is hereby possible to identify potential amino acid positions relevant to solvent-related enzyme engineering with high statistical significance. The method is particularly aimed at improving the reverse hydrolysis reaction rates in nonaqueous media. Candida antarctica lipase B (CALB) binds to a triglyceride-water interface with its substrate entrance channel oriented toward the hydrophobic substrate interface. The lipase-triglyceride-water system served as a model system for SFM to evaluate the influx of water molecules to the active site. As a proof of principle for SFM, a previously known water access pathway in CALB was identified as the primary water channel. In addition, a secondary water channel and two pathways for water access which contribute to water leakage between the protein and the triglyceride-water interface were identified.

Solvation in supercritical water

International Nuclear Information System (INIS)

Cochran, H.D.; Cummings, P.T.; Karaborni, S.

1991-01-01

The aim of this work is to determine the solvation structure in supercritical water composed with that in ambient water and in simple supercritical solvents. Molecular dynamics studies have been undertaken of systems that model ionic sodium and chloride, atomic argon, and molecular methanol in supercritical aqueous solutions using the simple point charge model of Berendsen for water. Because of the strong interactions between water and ions, ionic solutes are strongly attractive in supercritical water, forming large clusters of water molecules around each ion. Methanol is found to be a weakly-attractive solute in supercritical water. The cluster of excess water molecules surrounding a dissolved ion or polar molecule in supercritical aqueous solutions is comparable to the solvent clusters surrounding attractive solutes in simple supercritical fluids. Likewise, the deficit of water molecules surrounding a dissolved argon atom in supercritical aqueous solutions is comparable to that surrounding repulsive solutes in simple supercritical fluids. The number of hydrogen bonds per water molecule in supercritical water was found to be about one third the number in ambient water. The number of hydrogen bonds per water molecule surrounding a central particle in supercritical water was only mildly affected by the identify of the central particle--atom, molecule, or ion. These results should be helpful in developing a qualitative understanding of important processes that occur in supercritical water. 29 refs., 6 figs

Obtaining low temperature catalysts for methanol synthesis by no-waste process

Energy Technology Data Exchange (ETDEWEB)

Il' ko, E G; Sushchaya, L E; Bondar' , P G

1982-11-01

Low temperature production of catalysts for methanol synthesis involves considerable pollution of the environment as well as formation of side products. The authors propose producing such catalysts from joint precipitates of copper and zinc carbonates includiing stabilizers produced by decomposing solvents, then drying, aging and shaping. This method avoids waste water usually formed in scrubbing to remove ions of alkaline metals. Aluminum hydroxide is suggested as a stabilizer. The catalyst tablets prepared in this way were found to have activity like those produced by other methods, and were suitable for industrial use.

The reactivity of allyl and propargyl alcohols with solvated electrons: temperature and solvent effects

International Nuclear Information System (INIS)

Afanassiev, A.M.; Okazaki, K.; Freeman, G.R.

1979-01-01

The rate constants K 1 for the reaction of solvated electrons with allyl alcohol in a number of hydroxylic solvents differ by up to two orders of magnitude and decrease in the order tert-butyl alcohol > 2-propanol > l-propanol approximately ethanol > methanol approximately ethylene glycol > water. In methanol and ethylene glycol the rate constants (7 x 10 7 M -1 s -1 at 298 K) and activation energies (16 kJ/mol) are equal, in spite of a 32-fold difference in solvent viscosity (0.54 and 17.3 cP, respectively) and 3-fold difference in its activation energy (11 and 32 kJ/mol, respectively). The reaction in tert-butyl alcohol is nearly diffusion controlled and has a high activation energy that is characteristic of transport in that liquid (E 1 = 31 kJ/mol, E sub(eta) = 39 kJ/mol). The activation energies in the other alcohols are all 16 kJ/mol, and it is 14 kJ/mol in water. They do not correlate with transport properties. The solvent effect is connected primarily with the entropy of activation. The rate constants correlate with the solvated electron trap depth. When the electron affinity of the scavenger is small, a favorable configuration of solvent molecules about the electron/scavenger encounter pair is required for the electron jump to take place. The behavior of the rate parameters for propargyl alcohol is similar to that for allyl alcohol, but k 1 , A 1 , and E 1 are larger for the former. The ratio k(propargyl)/k(allyl) at 298 K equals 10.5 in water and decreases through the series, reaching 1.3 in tert-butyl alcohol. Rate parameters for several other scavengers are also reported. (author)

Utilization of Ethanolamine as Carbon Dioxide Absorber For

OpenAIRE

Yusuf, Asdiana Irma; Zakir, Muhammad; Maming, Maming

2015-01-01

Utilization of ethanolamine as carbon dioxide absober for estimating of coral age from langkai island via LSC (Liquid Scintillation Counting) method has been done. Focus is to analyze coral reefs taken from Langkai island surface which is relatively far from the influence of human activities. Chemical preparation was carried out by using a mixture of NaOH with H2O2 30% followed by a mixture of HClO4 with H2O2 30%, and finally with HCl solution to produce a clean sample with 8.6% weight reduct...

Oxo-exchange of gas-phase uranyl, neptunyl, and plutonyl with water and methanol.

Science.gov (United States)

Lucena, Ana F; Odoh, Samuel O; Zhao, Jing; Marçalo, Joaquim; Schreckenbach, Georg; Gibson, John K

2014-02-17

A challenge in actinide chemistry is activation of the strong bonds in the actinyl ions, AnO2(+) and AnO2(2+), where An = U, Np, or Pu. Actinyl activation in oxo-exchange with water in solution is well established, but the exchange mechanisms are unknown. Gas-phase actinyl oxo-exchange is a means to probe these processes in detail for simple systems, which are amenable to computational modeling. Gas-phase exchange reactions of UO2(+), NpO2(+), PuO2(+), and UO2(2+) with water and methanol were studied by experiment and density functional theory (DFT); reported for the first time are experimental results for UO2(2+) and for methanol exchange, as well as exchange rate constants. Key findings are faster exchange of UO2(2+) versus UO2(+) and faster exchange with methanol versus water; faster exchange of UO2(+) versus PuO2(+) was quantified. Computed potential energy profiles (PEPs) are in accord with the observed kinetics, validating the utility of DFT to model these exchange processes. The seemingly enigmatic result of faster exchange for uranyl, which has the strongest oxo-bonds, may reflect reduced covalency in uranyl as compared with plutonyl.

Esterase Active in Polar Organic Solvents from the Yeast Pseudozyma sp. NII 08165

Directory of Open Access Journals (Sweden)

Deepthy Alex

2014-01-01

Full Text Available Esterases/lipases active in water miscible solvents are highly desired in biocatalysis where substrate solubility is limited and also when the solvent is desired as an acyl acceptor in transesterification reactions, as with the case of biodiesel production. We have isolated an esterase from the glycolipid producing yeast-Pseudozyma sp. NII 08165 which in its crude form was alkali active, thermo stable, halo tolerant and also capable of acting in presence of high methanol concentration. The crude enzyme which maintained 90% of its original activity after being treated at 70°C was purified and the properties were characterized. The partially purified esterase preparation had temperature and pH optima of 60°C and 8.0 respectively. The enzyme retained almost complete activity in presence of 25% methanol and 80% activity in the same strength of ethanol. Conditions of enzyme production were optimized, which lead to 9 fold increase in the esterase yield. One of the isoforms of the enzyme LIP1 was purified to homogeneity and characterized. Purified LIP1 had a Km and Vmax of 0.01 and 1.12, respectively. The purified esterase lost its thermo and halo tolerance but interestingly, retained 97% activity in methanol.

Solvent consumption in non-catalytic alcohol solvolysis of biorefinery lignin

DEFF Research Database (Denmark)

Nielsen, J. B.; Jensen, A.; Schandel, Christian Bækhøj

2017-01-01

Lignin solvolysis in supercritical alcohols provides a method for producing a deoxygenated liquid bio-oil. Solvent consumption is however inevitable and due to the high cost of alcohols, relative to a bio-oil product, it can hinder commercial viability. In order to investigate the reactions...... of solvent consumption we studied solvolysis of biorefinery lignin in several primary alcohols. Lignin solvolysis in methanol, ethanol, 1-propanol and 1-butanol performed similarly with respect to bio-oil composition; however, methanol gave much lower bio-oil yield. Solvent consumption increases...... with reaction temperature for all alcohols and from 10 wt% at 300 °C to 35 wt% at 400 °C when using ethanol. The mechanism for solvent consumption was found mainly to take place through three different reactions: direct decomposition to gas through decarbonylation, formation of light condensation products...

Cooling crystallization of Indomethacin from different organic solvents

DEFF Research Database (Denmark)

Malwade, Chandrakant Ramkrishna; Qu, Haiyan

, 25, 35, and 45 °C. The solvents with varying polarities (ethanol, methanol, ethyl acetate, acetone, acetonitrile, and dichloromethane) were used for solubility measurement. Maximum solubility of IMC was observed in acetone, while acetonitrile showed the lowest solubility. Solid phase analysis...... of excess solute with XRPD and Raman spectroscopy confirmed formation of IMC solvate in acetone, methanol and dichloromethane at 15 °C. Based on solubility of IMC, the solvents ethanol, ethyl acetate, acetone, and dichloromethane were selected for crystallization experiments. Nucleation kinetics of IMC...... in selected solvents was investigated through the measurement of induction time at 5 °C and 15 °C. Longer induction times were observed for IMC in ethanol at both temperatures compared to the one in acetone. Metastable α form of IMC was obtained from ethanol, while solvate of IMC was produced from acetone....

Dynamics of Water Absorption and Evaporation During Methanol Droplet Combustion in Microgravity

Science.gov (United States)

Hicks, Michael C.; Dietrich, Daniel L.; Nayagam, Vedha; Williams, Forman A.

2012-01-01

The combustion of methanol droplets is profoundly influenced by the absorption and evaporation of water, generated in the gas phase as a part of the combustion products. Initially there is a water-absorption period of combustion during which the latent heat of condensation of water vapor, released into the droplet, enhances its burning rate, whereas later there is a water-evaporation period, during which the water vapor reduces the flame temperature suffciently to extinguish the flame. Recent methanol droplet-combustion experiments in ambient environments diluted with carbon dioxide, conducted in the Combustion Integrated Rack on the International Space Station (ISS), as a part of the FLEX project, provided a method to delineate the water-absorption period from the water-evaporation period using video images of flame intensity. These were obtained using an ultra-violet camera that captures the OH* radical emission at 310 nm wavelength and a color camera that captures visible flame emission. These results are compared with results of ground-based tests in the Zero Gravity Facility at the NASA Glenn Research Center which employed smaller droplets in argon-diluted environments. A simplified theoretical model developed earlier correlates the transition time at which water absorption ends and evaporation starts. The model results are shown to agree reasonably well with experiment.

Effect of Extraction Solvents and Drying Methods on the Physicochemical and Antioxidant Properties of Helicteres hirsuta Lour. Leaves

Directory of Open Access Journals (Sweden)

Hong Ngoc Thuy Pham

2015-12-01

Full Text Available Helicteres hirsuta Lour. (H. hirsuta L. is widely distributed in southeast Asian countries and has been used traditionally as a medicinal plant. However, optimal conditions for preparation of dried materials for further processing and suitable solvents for the extraction of bioactive compounds have not been investigated. The objective of this study was to evaluate the effects of different extraction solvents and different drying conditions on the physicochemical properties and antioxidant capacity of the H. hirsuta L. leaves. The results showed that both extraction solvents and drying conditions had a significant impact on physicochemical and antioxidant properties of H. hirsuta L. leaves. Among the five solvents investigated, water could extract the highest level of solid content and phenolic compounds, whereas methanol was more effective for obtaining flavonoids and saponins than other solvents. The leaves dried under either hot-air drying at 80 °C (HAD80, or vacuum drying at 50 °C (VD50 yielded the highest amount of total phenolic compounds (7.77 and 8.33 mg GAE/g, respectively and total flavonoid content (5.79 and 4.62 mg CE/g, respectively, and possessed the strongest antioxidant power, while leaves dried using infrared drying at 30 °C had the lowest levels of bioactive compounds. Phenolic compounds including flavonoids had a strong correlation with antioxidant capacity. Therefore, HAD80 and VD50 are recommended for the preparation of dried H. hirsuta L. leaves. Water and methanol are suggested solvents to be used for extraction of phenolic compounds and saponins from H. hirsuta L. leaves for the potential application in the nutraceutical and pharmaceutical industries.

Ethanol and water adsorption in methanol-derived ZIF-71

KAUST Repository

Lively, Ryan P.; Dose, Michelle E.; Thompson, Joshua A.; McCool, Benjamin A.; Chance, Ronald R.; Koros, William J.

2011-01-01

A room temperature method for synthesizing zeolitic imidizolate framework 71 (ZIF-71) is described. The methanol-based synthesis results in >95% yields (based on Zn) and produces crystals with 70% greater surface area than reported earlier. Ethanol uptake into the ZIF compares favorably with a recent modeling-based study. Water uptake was significantly higher than model predictions. © The Royal Society of Chemistry 2011.

Effect of solvent on the charging mechanisms of poly(ethylene glycol) in droplets

Science.gov (United States)

Soltani, Sepideh; Oh, Myong In; Consta, Styliani

2015-03-01

We examine the effect of solvent on the charging mechanisms of a macromolecule in a droplet by using molecular dynamics simulations. The droplet contains excess charge that is carried by sodium ions. To investigate the principles of the charging mechanisms of a macromolecule in a droplet, we simulate aqueous and methanol droplets that contain a poly(ethylene glycol) (PEG) molecule. We find that the solvent plays a critical role in the charging mechanism and in the manner that the sodiated PEG emerges from a droplet. In the aqueous droplets, the sodiated PEG is released from the droplet while it is being charged at a droplet charge state below the Rayleigh limit. The charging of PEG occurs on the surface of the droplet. In contrast to the aqueous droplets, in the methanol droplet, the sodiated PEG resides in the interior of the droplet and it may become charged at any location in the droplet, interior or surface. The sodiated PEG emerges from the droplet by drying-out of the solvent. Even though these two mechanisms appear to be phenomenologically similar to the widely accepted ion-evaporation and charge-residue mechanisms, they have fundamental differences from those. An integral part of the mechanism that the macromolecular ions emerge from droplets is the droplet morphology. Droplet morphologies give rise to different solvation interactions between the solvent and the macromolecule. In the water-sodiated PEG system, we find the extrusion of the PEG morphology, while in methanol-sodiated droplet, we find the "pearl-on-the-necklace" morphology and the extrusion of the sodiated PEG in the last stage of the desolvation process. These findings provide insight into the mechanisms that macromolecules acquire their charge in droplets produced in electrospray ionization experiments.

Vapor-liquid equilibria of a minute amount of furfural in water-methanol-ethanol system; Mizu-methanol-ethanol keichu no biryo no furfural no kieki heiko

Energy Technology Data Exchange (ETDEWEB)

Ikari, A.; Hatate, Y.; Uemura, Y. [Kagoshima University, Kagoshima (Japan). Faculty of Engineering

1997-01-10

Vapor-liquid equilibria of a water-methanol-ethanol system containing a minute amount of furfural were measured at atmospheric pressure by use of an Othmer-type still. The experimental results are represented by four triangular diagrams against the liquid compositions of the major components (water, methanol and ethanol), in which three diagrams show the vapor composition of the major components, respectively, and one diagram shows the equilibrium ratio of the trace component (furfural). The curved surface of the equilibrium ratio of the trace component exhibits a gentle downward slope in most areas, but shows a half-saddle face in the neighborhood of the water-ethanol side. 4 refs., 10 figs., 3 tabs.

Anti-inflammatory and cytotoxic effects of methanol, ethanol, and water extracts of Angelicae Dahuricae Radix.

Science.gov (United States)

Wang, Myeong-Hyeon; Jeong, Su-Hyeon; Guo, Huifang; Park, Jun-Beom

2016-01-01

Angelicae Dahuricae Radix has been used for the treatment of headaches, rhinitis, and colds in traditional medicine. Methanol, ethanol, and water extracts of Angelicae Dahuricae Radix were collected. A statistically significant reduction in the cellular viability of the mouse leukemic monocyte macrophage cell line was noted after treatment with water extracts of Angelicae Dahuricae Radix. Stimulation with lipopolysaccharides (LPS) for 24 h led to a robust increase in nitric oxide production, but Angelicae Dahuricae Radix at 400 μg/mL concentration significantly suppressed nitric oxide produced by the LPS-stimulated RAW 264.7 cells in 70% ethanol, absolute ethanol, 70% methanol, absolute methanol, and boiling water groups (P ethanol extract of Angelicae Dahuricae Radix suppressed the LPS-stimulated inducible nitric oxide synthase, interleukin-1β, and cycloxygenase-2 expression. Angelicae Dahuricae Radix showed significant cytotoxic effects on the human adenocarcinoma cell line and keratin-forming cell line. (J Oral Sci 58, 125-131, 2016).

On the solubility of nicotinic acid and isonicotinic acid in water and organic solvents

International Nuclear Information System (INIS)

Abraham, Michael H.; Acree, William E.

2013-01-01

Highlights: ► Solubilities of nicotinic acid and isonicotinic acids in organicsolvents have been determined. ► Solubilities are used to calculate Abraham descriptors for the two acids. ► These descriptors then yield water-solvent and gas-solvent partitions into numerous solvents. ► The solubility of the neutral acids in water is obtained. ► The method is straightforward and can be applied to any set of compound solubilities. -- Abstract: We have determined the solubility of nicotinic acid in four solvents and the solubility of isonicotinic acid in another four solvents. These results, together with literature data on the solubility of nicotinic acid in five other organic solvents and isonicotinic acid in four other organic solvents, have been analyzed through two linear Gibbs energy relationships in order to extract compound properties, or descriptors, that encode various solute–solvent interactions. The descriptors for nicotinic acid and isonicotinic acid can then be used in known equations for partition of solutes between water and organic solvents to predict partition coefficients and then further solubility in a host of organic solvents, as well as to predict a number of other physicochemical properties

Removal of technetium from alkaline nuclear-waste media by a solvent-extraction process using crown ethers

International Nuclear Information System (INIS)

Bonnesen, P.V.; Presley, D.J.; Haverlock, T.J.; Moyer, B.A.

1995-01-01

Crown ethers dissolved in suitably modified aliphatic kerosene diluents can be employed to extract technetium as pertechnetate anion (TcO 4 - ) with good extraction ratios from realistic simulants of radioactive alkaline nitrate waste. The modifiers utilized are non-halogenated and non-volatile, and the technetium can be removed from the solvent by stripping using water. The crown ethers bis-4,4'(5')[(tert-butyl)cyclohexano]-18-crown-6 (di-t-BuCH18C6) and dicyclohexano-18-crown-6 (DCH18C6) provide stronger TcO 4 - extraction than dicyclohexano-21-crown-7 and 4-tert-butylcyclohexano 15-crown-5. Whereas DCH18C6 provides somewhat higher TcO 4 - extraction ratios than the more lipophilic di-t-BuCH18C6 derivative, the latter was selected for further study owing to its lower distribution to the aqueous phase. Particularly good extraction and stripping results were obtained with di-t-BuCH 18C6 at 0.02 M in a 2:1 vol/vol blend of tributyl phosphate and Isopar reg-sign M. Using this solvent, 98.9% of the technetium contained (at 6 x 10 -5 M) in a Double-Shell Slurry Feed (DSSF) Hanford tank waste simulant was removed following two cross-current extraction contacts. Two cross-current stripping contacts with deionized water afforded removal of 99.1% of the technetium from the organic solvent

Reversible Activation of Halophilic β-lactamase from Methanol-Induced Inactive Form: Contrast to Irreversible Inactivation of Non-Halophilic Counterpart.

Science.gov (United States)

Tokunaga, Hiroko; Maeda, Junpei; Arakawa, Tsutomu; Tokunaga, Masao

2017-06-01

Effects of a water-miscible organic solvent, methanol, on the structure and activity of halophilic β-lactamase derived from Chromohalobacter sp.560 (HaBla), were investigated by means of circular dichroism (CD) measurement and enzymatic activity determination. Beta-lactamase activity was enhanced about 1.2-fold in the presence of 10-20% methanol. CD measurement of HaBla revealed different structures depending on the methanol concentration: native-like active form (Form I) in 10-20% methanol and methanol-induced inactive form at higher concentration (Form II in 40-60% and Form III in 75-80% methanol). Incubation of HaBla with 40% methanol led to the complete loss of activity within ~80 min accompanied by the formation of Form II, whose activity was recovered promptly up to ~80% of full activity upon dilution of the methanol concentration to 10%. In addition, when the protein concentration was sufficiently high (e.g., 0.7 mg/ml), HaBla activity of Form III in 75% methanol could be recovered in the same way (with slightly slower recovery rate), upon dilution of the methanol concentration. In contrast, non-halophilic β-lactamase from Escherichia coli K12 strain MG1655 (EcBla) was irreversibly denatured in the presence of 40% methanol. HaBla showed remarkable ability to renature from the methanol-induced inactive states.

Characteristics of indomethacin-saccharin (IMC-SAC) co-crystals prepared by an anti-solvent crystallization process.

Science.gov (United States)

Chun, Nan-Hee; Wang, In-Chun; Lee, Min-Jeong; Jung, Yun-Taek; Lee, Sangkil; Kim, Woo-Sik; Choi, Guang J

2013-11-01

The creation of co-crystals of various insoluble drug substances has been extensively investigated as a promising approach to improve their pharmaceutical performance. In this study, co-crystal powders of indomethacin and saccharin (IMC-SAC) were prepared by an anti-solvent (water) addition and compared with co-crystals by evaporation method. No successful synthesis of a pharmaceutical co-crystal powder via an anti-solvent approach has been reported. Among solvents examined, methanol was practically the only one that resulted in the formation of highly pure IMC-SAC co-crystal powders by anti-solvent approach. The mechanism of a preferential formation of IMC-SAC co-crystal to IMC was explained with two aspects: phase solubility diagram and solution complexation concept. Accordingly, the anti-solvent approach can be considered as a competitive route for producing pharmaceutical co-crystal powders with acceptable properties. Copyright © 2013 Elsevier B.V. All rights reserved.

Solvent optimization extraction of antioxidants from foxtail millet species' insoluble fibers and their free radical scavenging properties.

Science.gov (United States)

Bangoura, Mohamed Lamine; Nsor-Atindana, John; Ming, Zhou Hui

2013-11-15

In this study, water and 80% of four organic solvents were employed to optimize the extraction of antioxidants from two species of foxtail millet's insoluble fibers under the same temperature, time, and solid/solvent ratio. The results showed that the acetone was able to extract the maximum amount of antioxidants (2.32 mg/g fiber for white specie and 3.86 mg/g fiber for yellow specie) followed by methanol and propanol from both samples. The neutral and the ethanol on the other hand extracted small amount of the antioxidants from the two fiber materials. While considerable level of Total Polyphenols Content (TPC) was recorded in both the water and the organic solvents' extracts, only traces of Total Flavonoid content (TFC) were observed in water, methanol and ethanol extracts. Propanol and acetone extracts was negative to the TFC test. The potency of both white and yellow foxtail millets' insoluble fibers antioxidant extracts was investigated using five different in vitro tests. It was realized that there was a variation in their capacities to quench DPPH and ABTS(+) radicals for the time running of 0-60 min. The samples from the yellow cereal exhibited high inhibition capacity against ABTS(+). No correlation was observed between TPC and radical scavenging capacities for DPPH and ABTS(+). In general, the yellow species contained more antioxidants in comparison with the white one and this accounted for its high antioxidant activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Experimental study and modelisation of a pulse tube refrigerator

International Nuclear Information System (INIS)

Ravex, A.; Rolland, P.; Liang, J.

1992-01-01

A test bench for pulse tube refrigerator characterization has been built. In various configurations (basic pulse tube, orifice pulse tube and double inlet pulse tube), the ultimate temperature and the cooling power have been measured as a function of pressure wave amplitude and frequency for various geometries. A lowest temperature of 28 K has been achieved in a single staged double inlet configuration. A modelisation taking into account wall heat pumping, enthalpy flow and regenerator inefficiency is under development. Preliminary calculation results are compared with experimental data

Effect of spray-drying with organic solvents on the encapsulation, release and stability of fish oil.

Science.gov (United States)

Encina, Cristian; Márquez-Ruiz, Gloria; Holgado, Francisca; Giménez, Begoña; Vergara, Cristina; Robert, Paz

2018-10-15

Fish-oil (FO) was encapsulated with hydroxypropylcelullose (HPC) by conventional spray-drying with water (FO-water) and solvent spray-drying with ethanol (FO-EtOH), methanol (FO-MeOH) and acetone (FO-Acet) in order to study the effect of the solvent on the encapsulation efficiency (EE), microparticle properties and stability of FO during storage at 40 °C. Results showed that FO-Acet presented the highest EE of FO (92.0%), followed by FO-EtOH (80.4%), FO-MeOH (75.0%) and FO-water (71.1%). A decrease of the dielectric constant increased the EE of FO, promoting triglyceride-polymer interactions instead of oil-in-water emulsion retention. FO release profile in aqueous model was similar for all FO-microparticles, releasing only the surface FO, according to Higuchi model. Oxidative stability of FO significantly improved by spray-drying with MeOH, both in surface and encapsulated oil fractions. In conclusion, encapsulation of FO by solvent spray-drying can be proposed as an alternative technology for encapsulation of hydrophobic molecules. Copyright © 2018 Elsevier Ltd. All rights reserved.

Measurements of the phase behavior of ternary systems of interest to the gas process: II : the system CO2 + methanol + prednisolone

NARCIS (Netherlands)

Shariati - Sarabi, A.; Tesauro, C.; Reverchon, E.; Peters, C.J.

2012-01-01

In this work, the phase behavior of the ternary system carbon dioxide + methanol + prednisolone has been studied experimentally. For this purpose, carbon dioxide has been chosen as the anti-solvent gas, methanol as the organic solvent, and prednisolone as the model drug that should be micronized

Extraction of pesticides in soil using supercritical carbon dioxide co-solvents

International Nuclear Information System (INIS)

Forero, Jose R; Castro, Henry I; Guerrero, Jairo A.

2009-01-01

In this study, three organic solvents (ethyl acetate, methanol and acetone) were used as co solvent in supercritical fluid extraction (SFE) of a mixture of pesticides with different physical and chemical properties present in soil. These pesticides were determined by gas chromatography with electronic micro capture detector μECD and nitrogen-phosphorus detector (NPD), coupled in parallel. The extractions were performed on spiked soil samples using supercritical carbon dioxide (CO 2 SC) as the extracting phase to 35 celsius degrade and 14 MPa, using 10 mL of each co solvent and it was found that methanol offers the greatest efficiency in the extraction process obtaining recovery values between 51.24 and 123.50%.

Growth of (CH$_3$)$_2$NH$_2$CuCl$_3$ single crystals using evaporation method with different temperatures and solvents

OpenAIRE

Chen, L. M.; Tao, W.; Zhao, Z. Y.; Li, Q. J.; Ke, W. P.; Wang, X. M.; Liu, X. G.; Fan, C.; Sun, X. F.

2013-01-01

The bulk single crystals of of low-dimensional magnet (CH$_3$)$_2$NH$_2$CuCl$_3$ (DMACuCl$_3$ or MCCL) are grown by a slow evaporation method with different kinds of solvents, different degrees of super-saturation of solution and different temperatures of solution, respectively. Among three kinds of solvent, methanol, alcohol and water, alcohol is found to be the best one for growing MCCL crystals because of its structural similarity to the raw materials and suitable evaporation rate. The bes...

The effect of electrical conductivity on nanosecond discharges in distilled water and in methanol with argon bubbles

KAUST Repository

Hamdan, Ahmad

2017-03-27

We investigated the effect of a liquid\\'s electrical conductivity (EC) on the physical characteristics of electrical discharges in liquids with gaseous bubbles. Argon gas was supplied into the liquid to form an array of gaseous bubbles in between two electrodes (a pin-to-hollow electrode setup). Methanol and water were considered as base liquids, representing a low and a high dielectric permittivity (ϵ) liquid respectively, while potassium chloride (KCl) was added to control the EC of the liquids. When increasing the EC of the liquids, we found that the discharge probability was reduced by 46% for in-water and 38% for in-methanol discharges. We also found that the injected charge decreased by ∼4 μC as the EC increased. Moreover, as the gap distance increased from 1 to 2.5 mm, the injected charge decreased by 2 μC for in-water discharge and by 4 μC for in-methanol discharge. The plasma emission is another important parameter in characterizing discharges. With increasing the EC, the plasma emission volume decreased linearly by a factor of ∼5. The plasma lifetime was shortened by around 33% for in-water and 20% for in-methanol discharges in the case of d = 1 mm, while the decrease was 40% for in-water and 30% for in-methanol discharges in the case of d = 2.5 mm. Using the broadening characteristics of the Hα line, the electron density was estimated during the first 100 ns by ∼3 × 10 cm for in-water discharges and by ∼2 × 10 cm for in-methanol discharges, and it decreased by about one order of magnitude after 800 ns; note that n dependence on the EC was not significant. The reported findings provide further understanding of electrical discharges in bubbled liquids and highlight the influence of a liquid\\'s EC, which are useful in the development and optimization of the applications based on such process.

Production of synthetic methanol from air and water using controlled thermonuclear reactor power. 2. Capital investment and production costs

Energy Technology Data Exchange (ETDEWEB)

Dang, V D; Steinberg, M [Brookhaven National Lab., Upton, N.Y. (USA)

1977-01-01

Energy requirement and process development of methanol production from air and water using controlled thermonuclear fusion power was discussed in Part 1 (Steinberg et al., Energy conversion;17:97(1977)). This second part presents an economic analysis of the nine processes presented for obtaining carbon dioxide recovery from the atmosphere or the sea for methanol production. It is found that the most economical process of obtaining carbon dioxide is by stripping from sea water. The process of absorption/stripping by dilute potassium carbonate solution is found to be the most economical for the extraction of carbon dioxide from air at atmospheric pressure. The total energy required for methanol synthesis from these sources of carbon dioxide is 3.90 kWh(e)/lb methanol of which 90% is used for generation of hydrogen. The process which consumes the greatest amount of energy is the absorption/stripping of air by water at high pressure and amounts to 13.2 kWh(e)/lb methanol. With nuclear fusion power plants of 1000to 9000 MW(e), it is found that the cost of methanol using the extraction of carbon dioxide from air with dilute potassium carbonate solution is estimated to be in the range between Pound1.73 and Pound2.90/MMB.t.u. (energy equivalent - 1974 cost) for plant capacities of 21 400 to 193 000 bbl/day methanol. This methanol cost is competitive with gasoline in the range of 19 approximately equal to 33c/gallon. For the process of stripping of carbon dioxide from sea water, the cost is found to lie in the range of Pound1.65 to Pound2.71/MMB.t.u. (energy equivalent) for plant capacities of 21 700 to 195 000 bbl/day methanol which is competitive with gasoline in the range of 18 approximately equal to 30 c/gallon. Projection of methanol demand in the year 2020 is presented based on both its conventional use as chemicals and as a liquid fuel substituting for oil and gas.

Effect of some organic solvents on oxidative phosphorylation in rat liver mitochondria

DEFF Research Database (Denmark)

Syed, Muzeeb; Skonberg, Christian; Hansen, Steen Honoré

2013-01-01

The effect of acetone, acetonitrile, dimethyl sulfoxide (DMSO), ethanol and methanol on oxidative phosphorylation (ATP synthesis) in rat liver mitochondria has been studied. All the organic solvents inhibited the oxidative phosphorylation in a concentration dependent manner, but with differences...... in potencies. Among the tested organic solvents, acetonitrile and acetone were more potent than ethanol, methanol, and DMSO. There was no significant difference in oxidative phosphorylation, compared to controls, when the concentrations of acetone was below 1% (v/v), of acetonitrile below 2% (v/v), of DMSO...... below 10% (v/v), of ethanol below 5% or of methanol below 2%, respectively. There was complete inhibition of oxidative phosphorylation at 50% (v/v) of acetone, acetonitrile and ethanol. But in the case of DMSO and methanol there were some residual activities observed at the 50% concentration level. DMSO...

Mechanistic study on lowering the sensitivity of positive atmospheric pressure photoionization mass spectrometric analyses: size-dependent reactivity of solvent clusters.

Science.gov (United States)

Ahmed, Arif; Choi, Cheol Ho; Kim, Sunghwan

2015-11-15

Understanding the mechanism of atmospheric pressure photoionization (APPI) is important for studies employing APPI liquid chromatography/mass spectrometry (LC/MS). In this study, the APPI mechanism for polyaromatic hydrocarbon (PAH) compounds dissolved in toluene and methanol or water mixture was investigated by use of MS analysis and quantum mechanical simulation. In particular, four different mechanisms that could contribute to the signal reduction were considered based on a combination of MS data and quantum mechanical calculations. The APPI mechanism is clarified by combining MS data and density functional theory (DFT) calculations. To obtain MS data, a positive-mode (+) APPI Q Exactive Orbitrap mass spectrometer was used to analyze each solution. DFT calculations were performed using the general atomic and molecular electronic structure system (GAMESS). The experimental results indicated that methanol significantly reduced the signal in (+) APPI, but no significative signal reduction was observed when water was used as a co-solvent with toluene. The signal reduction is more significant especially for molecular ions than for protonated ions. Therefore, important information about the mechanism of methanol-induced signal reduction in (+) APPI-MS can be gained due its negative impact on APPI efficiency. The size-dependent reactivity of methanol clusters ((CH3 OH)n , n = 1-8) is an important factor in determining the sensitivity of (+) APPI-MS analyses. Clusters can compete with toluene radical ions for electrons. The reactivity increases as the sizes of the methanol clusters increase and this effect can be caused by the size-dependent ionization energy of the solvent clusters. The resulting increase in cluster reactivity explains the flow rate and temperature-dependent signal reduction observed in the analytes. Based on the results presented here, minimizing the sizes of methanol clusters can improve the sensitivity of LC/(+)-APPI-MS. Copyright © 2015 John

Direct and solvent-assisted thione–thiol tautomerism in 5-(thiophen-2-yl)-1,3,4-oxadiazole-2(3H)-thione: Experimental and molecular modeling study

Energy Technology Data Exchange (ETDEWEB)

Burcu Arslan, N. [Department of Computer Education and Instructional Technology, Faculty of Education, Giresun University, 28100 Giresun (Turkey); Özdemir, Namık, E-mail: namiko@omu.edu.tr [Department of Physics, Faculty of Arts and Sciences, Ondokuz Mayıs University, 55139 Samsun (Turkey); Dayan, Osman, E-mail: osmandayan@comu.edu.tr [Laboratory of Inorganic Synthesis and Molecular Catalysis, Çanakkale Onsekiz Mart University, 17020 Çanakkale (Turkey); Dege, Necmi [Department of Physics, Faculty of Arts and Sciences, Ondokuz Mayıs University, 55139 Samsun (Turkey); Koparır, Metin [Department of Chemistry, Faculty of Science, Fırat University, 23169 Elazığ (Turkey); Koparır, Pelin [Department of Chemistry, Forensic Medicine Institute, 44000 Malatya (Turkey); Muğlu, Halit [Department of Chemistry, Faculty of Arts and Sciences, Kastamonu University, 37200 Kastamonu (Turkey)

2014-08-17

Graphical abstract: - Highlights: • The molecule exists in the thione form in the solid state. • FT-IR and NMR data support the thione form. • The anti-thione conformer has the lowest energy. • The barrier height increases with increasing polarity of the solvent. • Multiple methanol or water-assisted thione–thiol tautomerism may happen. - Abstract: The compound has been synthesized and characterized by IR, NMR and X-ray diffraction. Quantum chemical calculations at B3LYP/6−311++G(d,p) level were performed to study the molecular and spectroscopic properties, conformational equilibrium, thione ↔ thiol tautomerism and intermolecular double proton transfer reaction of the compound. The obtained structural and spectroscopic results are well in agreement with the experimental data. The solvent effect on the proton transfer reaction was investigated in three solvents using the polarizable continuum model approximation and solvent-assisted mechanism. The anti-thione tautomer is the most stable isomer among the four possible structural forms both in the gas phase and in solution phase. A high tautomeric energy barrier is found for the tautomerism between the anti and syn forms of the compound, indicating a quite disfavored process. Although the presence of one methanol or water solvent molecule significantly lowers the energy barrier, it is not adequate for the reaction to occur.

Utilisation of chlorine-dioxide and peracetic acid as disinfectants of effluents from Bologna waste water treatment plant; Sperimentazione di tecniche di disinfezione mediante biossido di cloro e acido peracetico applicate alle acque reflue dell'impianto di trattamento della citta' di Bologna

Energy Technology Data Exchange (ETDEWEB)

Mancini, M.L. [Bologna Univ., Bologna (Italy). Dipt. di Ingegneria delle Strutture, dei Trasporti, delle Acque, del Rilevamento e del Territorio; Sorrentino, M.

2000-01-01

The necessity to optimize the disinfection phase in the treatment plant of waste water of Bologna made possible an experimental survey about the efficacy of two disinfectant agents utilized: chlorine-dioxide and peracetic acid. Object of the survey is to verify the possibility of utilize, full scale, also peracetic acid as disinfection agent. The experimentation regarded the reals flows adduced and discharged from the plant and it may be an useful reference to verify performance of post-treatment constructed wetlands. Particularly it has been possible to assay the efficacy of the different treatment in waste water with residual concentrations of suspended solids. [Italian] La necessita' di ottimizzare la fase di disinfezione nell'impianto di trattamento acque reflue della citta' di Bologna, sia per il miglioramento delle rese di inattivazione, sia per la riduzione dei costi di esercizio, ha reso necessaria un'indagine sperimentale sull'efficacia di due agenti disinfettanti utilizzati: il biossido di cloro e l'acido peracetico. Scopo dell'indagine e' quello di verificare la possibilita' di impiegare, a scala reale, per il refluo tipico dell'impianto di Bologna, anche l'acido peracetico quale agente di disinfezione. La sperimentazione, condotta ha interessato le portate reali addotte e scaricate dall'impianto e puo' costituire un riferimento utile verificare la fattibilita' igienico-sanitaria di post-trattamenti di lagunaggio o fertirrigazione. In particolare si e' potuta saggiare l'efficacia dei diversi sistemi di trattamento sui reflui aventi concentrazioni residue non trascurabili di solidi sospesi.

The removal of dimethyl phthalate (DMP) from contaminated water by advanced oxidation processes in the presence of methanol

Energy Technology Data Exchange (ETDEWEB)

Al-Tawabini, B.S. [Research Inst., King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)

2003-07-01

A bench-scale laboratory study was conducted to investigate the effect of alcohol (i.e. methanol) presence on the removal efficiency of phthalates from water using Fenton's reagent and UV/H{sub 2}O{sub 2} process. Dimethyl phthalate (DMP) was selected as a target compound. In one batch of experiments, only DMP was spiked into pure water, while in the other batch, DMP was initially dissolved in methanol prior to spiking into water samples. A UV lamp of 100 m Watt emitting at a wavelength of approximately 254 nm was used to provide the radiation. Temperature and pH conditions were kept constant at 25 C and 3, respectively. The results showed that Fenton's reagent was effective in reducing the concentration of DMP in water in the absence of the methanol. More than 90% of DMP was removed within 45 minutes at hydrogen peroxide (H{sub 2}O{sub 2}) and ferrous ion (Fe{sup 2+}) concentrations of 1.0 and 0.4 mM respectively. However, Fenton's reagent failed to do so in the presence of methanol. On the other hand, results showed that UV/H{sub 2}O{sub 2} system was effective in removing DMP from both pure, as well as methanol-spiked water. The results clearly indicated that UV radiation plays a fundamental role in the degradation of the target compound. (orig.)

Effect of sorbitol and glycerol on the stability of trypsin and difference between their stabilization effects in the various solvents.

Science.gov (United States)

Pazhang, Mohammad; Mehrnejad, Faramarz; Pazhang, Yaghub; Falahati, Hanieh; Chaparzadeh, Nader

2016-01-01

The effect of glycerol and sorbitol on the stability of porcine pancreas trypsin was investigated in this work. Molecular dynamics simulation and thermostability results showed that trypsin has two flexible regions, and polyols (sorbitol and glycerol) stabilize the enzyme by decreasing the flexibility of these regions. Radial distribution function results exhibited that sorbitol and glycerol were excluded from the first water layer of the enzyme, therefore decrease the flexibility of the regions by preferential exclusion. Also, results showed that the stabilization effect of sorbitol is more than glycerol. This observation could be because of the larger decrease in the fluctuations of trypsin in the presence of sorbitol. We also examined the role of solvent's hydrophobicity in enzyme stabilization by sorbitol and glycerol. To do so, the thermostability of trypsin was evaluated in the presence of solvents with different hydrophobicity (methanol, ethanol, isopropanol and n-propanol) in addition to the polyols. Our results depicted that glycerol is a better stabilizer than sorbitol in the presence of hydrophobic solvents (n-propanol), whereas sorbitol is a better stabilizer than glycerol in the presence of hydrophilic solvents (methanol). © 2015 International Union of Biochemistry and Molecular Biology, Inc.

Microbial process for the preparation of acetic acid as well as solvent for its extraction from the fermentation broth

Science.gov (United States)

Gaddy, James L.; Clausen, Edgar C.; Ko, Ching-Whan; Wade, Leslie E.; Wikstrom, Carl V.

2002-01-01

A modified water-immiscible solvent useful in the extraction of acetic acid from aqueous streams is a substantially pure mixture of isomers of highly branched di-alkyl amines. This solvent is substantially devoid of mono-alkyl amines and alcohols. Solvent mixtures formed of such a modified solvent with a desired cosolvent, preferably a low boiling hydrocarbon which forms an azeotrope with water are useful in the extraction of acetic acid from aqueous gaseous streams. An anaerobic microbial fermentation process for the production of acetic acid employs such solvents, under conditions which limit amide formation by the solvent and thus increase the efficiency of acetic acid recovery. Methods for the direct extraction of acetic acid and the extractive fermentation of acetic acid also employ the modified solvents and increase efficiency of acetic acid production. Such increases in efficiency are also obtained where the energy source for the microbial fermentation contains carbon dioxide and the method includes a carbon dioxide stripping step prior to extraction of acetic acid in solvent.

Structure and spectroscopic properties of N,S-coordinating 2-methylsulfanyl-N-[(1H-pyrrol-2-ylmethylidene]aniline methanol monosolvate

Directory of Open Access Journals (Sweden)

D. Douglas Richards

2015-10-01

Full Text Available The reaction of pyrrole-2-carboxaldehyde and 2-(methylsulfanylaniline in refluxing methanol gave an olive-green residue in which yellow crystals of the title compound, C12H12N2S·CH3OH, were grown from slow evaporation of methanol at 263 K. In the crystal, hydrogen-bonding interactions link the aniline molecule and a nearby methanol solvent molecule. These units are linked by a pair of weak C—H...Omethanol interactions, forming inversion dimers consisting of two main molecules and two solvent molecules.

Compact Fuel-Cell System Would Consume Neat Methanol

Science.gov (United States)

Narayanan, Sekharipuram; Kindler, Andrew; Valdez, Thomas

2007-01-01

In a proposed direct methanol fuel-cell electric-power-generating system, the fuel cells would consume neat methanol, in contradistinction to the dilute aqueous methanol solutions consumed in prior direct methanol fuel-cell systems. The design concept of the proposed fuel-cell system takes advantage of (1) electro-osmotic drag and diffusion processes to manage the flows of hydrogen and water between the anode and the cathode and (2) evaporative cooling for regulating temperature. The design concept provides for supplying enough water to the anodes to enable the use of neat methanol while ensuring conservation of water for the whole fuel-cell system.

Electrical double layer structure at the gallium metals in a methanol solution of a surface-inactive electrolyte

International Nuclear Information System (INIS)

Emets, V.V.

1997-01-01

The structure of double electric layer on Ga-, In-Ga- and Tl-Ga-electrodes in methanol solutions of surface-inactive electrolyte has been studied. It is shown that in the absence of chemisorption interaction between metal and solvent, the distance of the nearest approach of methanol dipoles to the surface of Ga-, In-Ga- and Tl-Ga-electrodes is practically the same. Accordingly, the specificity of the metals contact with solvent is reduced solely to their chemisorption interaction. In the zero charge area and for negative charges the chemisorption interaction with methanol molecules increases in the sequence Tl-Ga< In-Ga< Ga. The growth correlates both with the metals acceptor ability towards electron, which is characterized by the work of metal electron escape to vacuum, and donor ability of the solvent characterized by its donor number

Thermodynamics of H+/Cs+ exchange on amorphous zirconium phosphate in mixed solvents

International Nuclear Information System (INIS)

Misak, N.Z.; Mikhail, E.M.

1983-01-01

In aqueous, 30% isopropanol and acetone, and up to 90% methanol, the H + /Cs + exchange on zirconium phosphate is entropy directed, while in 60% isopropanol and acetone it is enthalpy directed and a selectivity reversal occurs. ΔF 0 decreases in all cases with increasing addition of the organic solvent. ΔH 0 becomes appreciably negative (ΔH 0 = 0 in aqueous medium) and ΔS 0 decreases appreciably on addition of 30% organic solvent, but they increase with further addition. In presence of methanol, ion-solvent interaction effects are counteracted by effects of solid phase interactions but the former effects predominate and lead to decrease of ΔF 0 . On going from 30 to 90 % methanol, positive enthalpy and entropy changes occur due to solid phase interactions involving probably the dehydration of the ingoing Cs + . In presence of up to 60% acetone, ΔF 0 (or selectively constant) changes mainly due to ion-solvent interactions and can be theoretically calculated from the value in the aqueous medium by use of transfer thermodynamics data. This is probably due to a limited imbibition of acetone. (author)

Acidic resin-catalysed conversion of fructose into furan derivatives in low boiling point solvents.

Science.gov (United States)

Zhu, Hong; Cao, Quan; Li, Chunhu; Mu, Xindong

2011-09-27

Conversion of fructose into furan derivatives 5-hydroxymethylfurfural (HMF) and 5-methoxymethylfurfural (MMF) is performed in tetrahydrofuran (THF) and methanol-organic solvent systems, catalysed by an acidic resin Amberlyst-15. The melted fructose can be converted into HMF on the surface of the solid resin catalyst in the presence of THF as an extracting phase, which is a good solvent for HMF and other by-products. The solid resin catalyst can be reused eleven times without losing its catalytic ability, with an average HMF yield of approximately 50%. Upon the addition of methanol, the generated HMF can further react with methanol to form MMF, and the total yield of HMF and MMF could be promoted to 65%. GC-MS analysis confirms the formation of a small amount of methyl levulinate in methanolorganic solvent system. Copyright © 2011 Elsevier Ltd. All rights reserved.

Study of acid-base properties in various water-salt and water-organic solvent mixtures

International Nuclear Information System (INIS)

Lucas, M.

1969-01-01

Acid-base reactions have been studied in water-salt mixtures and water organic solvent-mixtures. It has been possible to find some relations between the displacement of the equilibria and the numerical value of water activity in the mixture. First have been studied some equilibria H + + B ↔ HB + in salt-water mixtures and found a relation between the pK A value, the solubility of the base and water activity. The reaction HO - + H + ↔ H 2 O has been investigated and a relation been found between pK i values, water activity and the molar concentration of the salt in the mixture. This relation is the same for every mixture. Then the same reactions have been studied in organic solvent-water mixtures and a relation found in the first part of the work have been used with success. So it has been possible to explain easily some properties of organic water-mixture as the shape of the curves of the Hammett acidity function Ho. (authors) [fr

Influence of the solvents on the γ-ray polymerization of acrylic acid. II

International Nuclear Information System (INIS)

Laborie, F.

1977-01-01

The presence of plurimolecular H-bonded aggregates in the acrylic acid allows the polymer to involve some stereoregular sequences. This effect is made easier when some polymer is already formed in the reacting medium: the aggregates are stabilized by hydrogen bonds with the polymer which gives rise to a matrix effect. Two groups of solvents have been characterized by examination of the monomer's association forms in solution. In a first group of solvents (methanol--dioxan--water), the aggregates are maintained and reinforced; in the second one, acrylic acid exists only as cyclic dimers (hydrocarbons--chlorinated solvents). The difference between the association forms of the monomer involves some important modifications on the kinetics of polymerization and the structure of the obtained polymers. In the solvents of the first group, the obtained polymers are crystallizable and may involve syndiotactic sequences, while in the presence of the solvents of the second group no crystallization or stereoregularity of the polymer can occur. A very close correlation is thus found between the aggregated structure of the monomer, the polymerization kinetics, and the structure of the polymers

Effects of solvent evaporation on water sorption/solubility and nanoleakage of adhesive systems

Directory of Open Access Journals (Sweden)

Talita Baumgratz Cachapuz CHIMELI

2014-07-01

Full Text Available Objective: To evaluate the influence of solvent evaporation in the kinetics of water diffusion (water sorption-WS, solubility-SL, and net water uptake and nanoleakage of adhesive systems. Material and Methods: Disk-shaped specimens (5.0 mm in diameter x 0.8 mm in thickness were produced (N=48 using the adhesives: Clearfil S3 Bond (CS3/Kuraray, Clearfil SE Bond - control group (CSE/Kuraray, Optibond Solo Plus (OS/Kerr and Scotchbond Universal Adhesive (SBU/3M ESPE. The solvents were either evaporated for 30 s or not evaporated (N=24/per group, and then photoactivated for 80 s (550 mW/cm2. After desiccation, the specimens were weighed and stored in distilled water (N=12 or mineral oil (N=12 to evaluate the water diffusion over a 7-day period. Net water uptake (% was also calculated as the sum of WS and SL. Data were submitted to 3-way ANOVA/Tukey's test (α=5%. The nanoleakage expression in three additional specimens per group was also evaluated after ammoniacal silver impregnation after 7 days of water storage under SEM. Results: Statistical analysis revealed that only the factor "adhesive" was significant (p<0.05. Solvent evaporation had no influence in the WS and SL of the adhesives. CSE (control presented significantly lower net uptake (5.4%. The nanoleakage was enhanced by the presence of solvent in the adhesives. Conclusions: Although the evaporation has no effect in the kinetics of water diffusion, the nanoleakage expression of the adhesives tested increases when the solvents are not evaporated.

A Masing Event in NGC 6334I: Contemporaneous Flaring of Hydroxyl, Methanol and Water Masers

Science.gov (United States)

MacLeod, G. C.; Smits, D. P.; Goedhart, S.; Hunter, T. R.; Brogan, C. L.; Chibueze, J. O.; van den Heever, S. P.; Thesner, C. J.; Banda, P. J.; Paulsen, J. D.

2018-04-01

As a product of the maser monitoring program with the 26 m telescope of the Hartebeesthoek Radio Astronomy Observatory (HartRAO), we present an unprecedented, contemporaneous flaring event of 10 maser transitions in hydroxyl, methanol, and water that began in 2015 January in the massive star-forming region NGC 6334I in the velocity range -10 to -2 km s-1. The 6.7 GHz methanol and 22.2 GHz water masers began flaring within 22 days of each other, while the 12.2 GHz methanol and 1665 MHz hydroxyl masers flared 80 and 113 days later respectively. The 1665 MHz, 6.7 GHz, and 22.2 GHz masers have all remained in their flared state for nearly 3 years. The brightest flaring components increased by factors of 66, 21, 26, and 20 in the 12.2 and 6.7 GHz methanol, 1665 MHz hydroxyl and 22.2 GHz water maser transitions respectively; some weaker components increased by up to a factor of 145. We also report new maser emission in the 1720, 6031, and 6035 MHz OH lines and the 23.1 GHz methanol line, along with the detection of only the fifth 4660 MHz OH maser. We note the correlation of this event with the extraordinary (sub)millimeter continuum outburst from the massive protostellar system NGC 6334I-MM1 and discuss the implications of the observed time lags between different maser velocity components on the nature of the outburst. Finally, we identify two earlier epoch maser flaring events likely associated with this object, which suggest a recurring accretive phenomenon that generates powerful radiative outbursts.

Effect of methanol on the liquefaction reaction of biomass in hot compressed water under microwave energy

Science.gov (United States)

Junming Xu; Jianchun Jiang; Chun-Yun Hse; Todd F. Shupe

2013-01-01

Liquefaction of sawdust was studied in methanol-water solutions using an acid catalyst under microwave energy. The effect of the methanol concentration on the changes of components in the liquefied products was analyzed by gas chromatography−mass spectrometry (GC−MS). It was found that 5-hydroxymethylfurfural (HMF) and levulinic acid are the...

Comparison of the thermal decomposition processes of several aminoalcohol-based ZnO inks with one containing ethanolamine

Energy Technology Data Exchange (ETDEWEB)

Gómez-Núñez, Alberto [University of Barcelona, Department of Electronics, Martí i Franquès 1, E08028-Barcelona (Spain); Roura, Pere [University of Girona, Department of Physics, Campus Montilivi, Edif. PII, E17071-Girona, Catalonia (Spain); López, Concepción [University of Barcelona, Department of Inorganic Chemistry, Martí i Franquès 1, E08028-Barcelona (Spain); Vilà, Anna, E-mail: avila@el.ub.edu [University of Barcelona, Department of Electronics, Martí i Franquès 1, E08028-Barcelona (Spain)

2016-09-15

Highlights: • Four alternatives to ethanolamine as stabilizer for the chemical synthesis of ZnO with zinc acetate dihydrate are proposed: aminopropanol, aminomethyl butanol, aminophenol and aminobenzyl alcohol. • Thermal decomposition processes described. Nitrogen cyclic compounds result. • Molecule flexibility helps decomposition, and in particular aliphatic aminoalcohols (quite flexible) decompose the precursor at lower temperatures than aromatic ones (more rigid). • Aminopropanol, aminomethyl butanol and aminobenzyl crystallize ZnO at a lower temperature than ethanolamine. • Nitrogen cyclic specimens have been identified and evolve in all cases (included ethanolamine) at temperatures up to 600 °C. - Abstract: Four inks for the production of ZnO semiconducting films have been prepared with zinc acetate dihydrate as precursor salt and one among the following aminoalcohols: aminopropanol (APr), aminomethyl butanol (AMB), aminophenol (APh) and aminobenzyl alcohol (AB) as stabilizing agent. Their thermal decomposition process has been analyzed in situ by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and evolved gas analysis (EGA), whereas the solid product has been analysed ex-situ by X-ray diffraction (XRD) and infrared spectroscopy (IR). Although, except for the APh ink, crystalline ZnO is already obtained at 300 °C, the films contain an organic residue that evolves at higher temperature in the form of a large variety of nitrogen-containing cyclic compounds. The results indicate that APr can be a better stabilizing agent than ethanolamine (EA). It gives larger ZnO crystal sizes with similar carbon content. However, a common drawback of all the amino stabilizers (EA included) is that nitrogen atoms have not been completely removed from the ZnO film at the highest temperature of our experiments (600 °C).

Thermal tests on UF6 containers and valves modelisation and extrapolation on real fire situations

International Nuclear Information System (INIS)

Duret, B.; Warniez, P.

1988-12-01

From realistic tests on containers or on valves, we propose a modelisation which we apply to 3 particular problems: resistance of a 48 Y containers, during a fire situation. Influence of the presence of a valve. Evaluation of a leakage through a breach, mechanically created before a fire

Use of controlled thermonuclear reactor fusion power for the production of synthetic methanol fuel from air and water

International Nuclear Information System (INIS)

Steinberg, M.; Vi Duong Dang.

1975-04-01

Methanol synthesis from carbon dioxide, water and nuclear fusion energy is extensively investigated. The entire system is analyzed from the point of view of process design and economic evaluation of various processes. The main potential advantage of a fusion reactor (CTR) for this purpose is that it provides a large source of low cost environmentally acceptable electric power based on an abundant fuel source. Carbon dioxide is obtained by extraction from the atomsphere or from sea water. Hydrogen is obtained by electrolysis of water. Methanol is synthesized by the catalytic reaction of carbon dioxide and hydrogen. The water electrolysis and methanol synthesis units are considered to be technically and commercially available. The benefit of using air or sea water as a source of carbon dioxide is to provide an essentially unlimited renewable and environmentally acceptabe source of hydrocarbon fuel. Extraction of carbon dioxide from the atmosphere also allows a high degree of freedom in plant siting. (U.S.)

Ultrasonication-Assisted Solvent Extraction of Quercetin Glycosides from ‘Idared’ Apple Peels

Directory of Open Access Journals (Sweden)

Gwendolyn M. Huber

2011-11-01

Full Text Available Quercetin and quercetin glycosides are physiologically active flavonol molecules that have been attributed numerous health benefits. Recovery of such molecules from plant matrices depends on a variety of factors including polarity of the extraction solvent. Among the solvents of a wide range of dielectric constants, methanol recovered the most quercetin and its glycosides from dehydrated ‘Idared’ apple peels. When ultra-sonication was employed to facilitate the extraction, exposure of 15 min of ultrasound wavelengths of dehydrated apple peel powder in 80% to 100% (v/v methanol in 1:50 (w:v solid to solvent ratio provided the optimum extraction conditions for quercetin and its glycosides. Acidification of extraction solvent with 0.1% (v/v or higher concentrations of HCl led to hydrolysis of naturally occurring quercetin glycosides into the aglycone as an extraction artifact.

Chemistry in production of heavy water and industrial solvents

International Nuclear Information System (INIS)

Thomas, P.G.

2015-01-01

Industries are the temples of modern science built on the robust foundation of science and technology. The genesis of giant chemical industries is from small laboratories where the scientific thoughts are fused and transformed into innovative technologies Heavy water production is an energy intensive giant chemical industry where various hazardous and flammable chemicals are handled, extreme operating conditions are maintained and various complex chemical reactions are involved. Chemistry is the back bone to all chemical industrial activities and plays a lead role in heavy water production also. Heavy Water Board has now mastered the technology of design, construction, operation and maintenance of Heavy Water plants as well as fine tuning of the process make it more cost effective and environment friendly. Heavy Water Board has ventured into diversified activities intimately connected with our three stages of Nuclear Power Programme. Process development for the production of nuclear grade solvents for the front end and back end of our nuclear fuel cycle is one area where we have made significant contributions. Heavy Water Board has validated, modified and fine-tuned the synthesis routes for TBP, D2EHPA, TOPO, TAPO TIAP, DNPPA, D2EHPA-II, DHOA etc and these solvents were accepted by end users. Exclusive campaigns were carried out in laboratory scale, bench scale and pilot plant scale before scaling up to industrial scale. The process chemistry is understood very well and chemical parameters were monitored in every step of the synthesis. It is a continual improvement cycle where fine tuning is carried out for best quality and yield of product at lowest cost. In this presentation, an attempt is made to highlight the role of chemistry in the production of Heavy Water and industrial solvents

Activity and conformation of lysozyme in molecular solvents, protic ionic liquids (PILs) and salt-water systems.

Science.gov (United States)

Wijaya, Emmy C; Separovic, Frances; Drummond, Calum J; Greaves, Tamar L

2016-09-21

Improving protein stabilisation is important for the further development of many applications in the pharmaceutical, specialty chemical, consumer product and agricultural sectors. However, protein stabilization is highly dependent on the solvent environment and, hence, it is very complex to tailor protein-solvent combinations for stable protein maintenance. Understanding solvent features that govern protein stabilization will enable selection or design of suitable media with favourable solution environments to retain protein native conformation. In this work the structural conformation and activity of lysozyme in 29 solvent systems were investigated to determine the role of various solvent features on the stability of the enzyme. The solvent systems consisted of 19 low molecular weight polar solvents and 4 protic ionic liquids (PILs), both at different water content levels, and 6 aqueous salt solutions. Small angle X-ray scattering, Fourier transform infrared spectroscopy and UV-vis spectroscopy were used to investigate the tertiary and secondary structure of lysozyme along with the corresponding activity in various solvation systems. At low non-aqueous solvent concentrations (high water content), the presence of solvents and salts generally maintained lysozyme in its native structure and enhanced its activity. Due to the presence of a net surface charge on lysozyme, electrostatic interactions in PIL-water systems and salt solutions enhanced lysozyme activity more than the specific hydrogen-bond interactions present in non-ionic molecular solvents. At higher solvent concentrations (lower water content), solvents with a propensity to exhibit the solvophobic effect, analogous to the hydrophobic effect in water, retained lysozyme native conformation and activity. This solvophobic effect was observed particularly for solvents which contained hydroxyl moieties. Preferential solvophobic effects along with bulky chemical structures were postulated to result in less

Preferential solvation of ions in mixed solvents. 6: Univalent anions in aqueous organic solvents according to the inverse Kirkwood-Buff integral (IKBI) approach

International Nuclear Information System (INIS)

Marcus, Yizhak

2007-01-01

The inverse Kirkwood-Buff integral (IKBI) approach is applied to the preferential solvation of F - , Cl - , Br - , I - , and ClO 4 - in aqueous mixtures of the co-solvents (S) methanol (MeOH), ethanol (EtOH), t-butanol (t-BuOH), 1,2-ethanediol (EG), glycerol (Gly), acetone (Me 2 CO), acetonitrile (MeCN), formamide (FA), N,N-dimethylformamide (DMF), N,N,N',N',N'',N''-hexamethyl phosphoric triamide (HMPT), and dimethylsulfoxide (DMSO), as far as the relevant data exist in the literature. Fluoride anions are selectively solvated by the water up to large mole fractions (x S ≥ 0.4) of S = EtOH, t-BuOH, Me 2 CO, MeCN, and DMF, and up to lower contents (x S ∼ 0.1) of MeOH, EG, FA, and DMSO. The other anions are preferentially solvated by water to diminishing extent as their sizes become larger, and the largest ones show some preference for S in water-rich mixtures of MeOH and FA, whereas in aqueous Gly even chloride is preferentially solvated by the Gly. The competition between the co-solvent and the anion for the hydrogen bonds that water molecules donate is the main cause for the observed preferential solvation behaviour

Chromatographic separation of rhenium in alumina-methanol/sulfuric acid system

International Nuclear Information System (INIS)

Oguma, Koichi

1983-01-01

The adsorption behavior of a number of metals on alumina was surveyed in a methanol-(0.005 -- 0.5) M H 2 SO 4 (3 : 1 v/v) developing solvent by thin-layer chromatography. Over the acid concentration range tested, Re(VII) does not favor the alumina phase to any great extent while the most other metals are strongly adsorbed on alumina. These findings allowed to establish a column chromatographic technique for selective separation of rhenium in a methanol-0.05 M H 2 SO 4 (3 : 1 v/v) eluent. The separation technique thus established was applied to molybdenite analysis for rhenium. About 100-mg powdered sample containing ca. 100 ppm rhenium was decomposed with HNO 3 and then evaporated nearly to dryness. The residue was dissolved in NH 4 OH and the excess NH 4 OH was expelled by evaporation to dryness. The residue was dissolved in 2.5-ml 0.5 M H 2 SO 4 and 10-ml water, the insoluble materials filtered off, and the filtrate diluted to exactly 25 ml with water. A 10-ml aliquot of this solution was mixed with 30-ml methanol and the mixture was passed through a column (diameter 15 mm, bed height 30 mm) containing 5 g of alumina. The column was then washed with 20 ml of a methanol-0.05 M H 2 SO 4 (3 : 1 v/v) mixture. Rhenium was recovered from the loaded solution and the subsequent washings, and was determined spectrophotometrically with Methylene Blue as a chromogenic reagent. The values obtained from four samples of molybdenite are in good agreement with those obtained by neutron activation analysis. The relative standard deviation (n = 4; calculated from the range) was between 2.0 and 5.2 %. (author)

Reuse of treated waste water for the irrigation of ornamental plants. The case of Pistoia; Riuso di acque reflue depurate di specie ornamentali: l'impianto pilota di Pistoia

Energy Technology Data Exchange (ETDEWEB)

Gori, R.; Lubello, C. [Florence Univ., Florence (Italy). Dipt. di Ingegneria Civile

1999-12-01

After a brief introduction on irrigation waste water reuse, the paper deals with the case of Pistoia (italy), the most important nursery area in Italy, which has developed an experiment for evaluating the effects of waste water treatment plant effluent irrigation. The better physiological and growth parameters of plants irrigated with the effluent shows that it could be a valid alternative of water and fertilizer nutrients resources for ornamental plants. [Italian] Dopo una breve introduzione sul riuso delle acque reflue a fini irrigui, il lavoro affronta il caso di Pistoia, sede della maggiore area vivaistica italiana, che utilizza le acque reflue dal 1998 con una sperimentazione volta a verificare gli effetti dell'irrigazione con l'effluente dell'impianto di depurazione centrale. Le piante cosi' irrigate hanno mostrato parametri di crescita e fisiologici generalmente migliori di quelli riscontrati sulle piante irrigate con i metodi tradizionali.

Relation between the interfacial tension in an organic solvent-water system and the parameters of the solvating capacity of the solvent

International Nuclear Information System (INIS)

Nikitin, S.D.; Shmidt, V.S.

1987-01-01

It was shown that there is a linear relation between the empirical DE (diluent effect) and E/sub T/ parameters, which characterize the solvating capacity of the solvent, and the interfacial tension in an organic solvent-water two-phase system. Analysis of the sample correlation coefficients shows that the relation between the interfacial tension and the DE parameters of the solvents is closer to linear than the corresponding relation for the E/sub T/ parameters. During analysis of the data for 31 solvents it was established that the largest inverse correlation coefficient r = -0.98 is obtained with an equation of the DE = a + bσ/rho 1/3, type, were a and b are constants, and rho is the density of the solvent. The regression equation has the following form: DE = 7.586 - 0.147 σ/rho 1/3. Since the interfacial activity of hydrophobic surfactants decreases linearly with increase in the DE values, it follows from the obtained equation that decrease of the interfacial tension at the water-organic solvent interface must lead to a decrease in the interfacial activity of hydrophobic surfactants present in the system

Performance of direct methanol fuel cell with a palladium–silica nanofibre/Nafion composite membrane

International Nuclear Information System (INIS)

Thiam, H.S.; Daud, W.R.W.; Kamarudin, S.K.; Mohamad, A.B.; Kadhum, A.A.H.; Loh, K.S.; Majlan, E.H.

2013-01-01

Highlights: • This study introduces Pd–SiO 2 Carbon Nano Fibre as an additive to Nafion membrane. • It investigates the effects of membrane annealing temperature and casting solvent. • Results show that Pd–SiO 2 fibre/Nafion performs lower methanol permeability. • This could effectively reduces methanol crossover in direct methanol fuel cell. - Abstract: Palladium–silica nanofibres (Pd–SiO 2 fibre) were adopted as an additive to Nafion recast membranes in order to reduce methanol crossover and improve the cell performance. The performance of a membrane electrode assembly (MEA) with fabricated composite membrane was evaluated through a passive air-breathing single cell direct methanol fuel cell (DMFC). The limiting crossover current density was measured to determine the methanol permeation in the DMFC. The effects of membrane annealing temperature and casting solvent of composite membrane on the cell performance were investigated and are discussed here. Compared to recast Nafion with the same thickness (150 μm), the Pd–SiO 2 fibre/Nafion composite membrane exhibited higher performance and lower methanol permeability. A maximum power density of 10.4 mW cm −2 was obtained with a 2 M methanol feed, outperforming the much thicker commercial Nafion 117 with a power density of 7.95 mW cm −2 under the same operating conditions. The experimental results showed that the Pd–SiO 2 fibre as inorganic fillers for Nafion could effectively reduce methanol crossover and improve the membrane performance in DMFC applications

A bioinspired color-changing polystyrene microarray as a rapid qualitative sensor for methanol and ethanol

International Nuclear Information System (INIS)

Kuo, Wen-Kai; Weng, Hsueh-Ping; Hsu, Jyun-Jheng; Yu, Hsin Her

2016-01-01

Polystyrene (PS) microspheres were synthesized by emulsifier-free emulsion polymerization and arranged in an array of closely packed, opal-like photonic crystals by slow self-assembly through dip-coating. This periodic array of PS microspheres was then employed as a rapid qualitative sensor for methanol and ethanol. Both solvents could be detected rapidly based on the routes of their reflection coordinates in the chromaticity diagram or directly by the naked eye on the basis of the change in color within 1 min once a solvent sample had been placed on the PS photochromic sensor. This opal-like PS sensor can thus not only be employed as a rapid sensor for methanol and ethanol but can also be used as a powerful tool for the fast screening of illicit drugs and toxic chemicals during forensic investigations. - Highlights: • Opal-like array of polystyrene (PS) microspheres is synthesized by self-assembly. • This periodic PS array is used as a rapid sensor for methanol and ethanol. • Solvents are detected by routes of reflection coordinates in chromaticity diagram. • They are also detected directly by naked eye based on change in color of sensor. • The color change is irreversible for methanol but reversible for ethanol.

A bioinspired color-changing polystyrene microarray as a rapid qualitative sensor for methanol and ethanol

Energy Technology Data Exchange (ETDEWEB)

Kuo, Wen-Kai, E-mail: wkkuo@nfu.edu.tw [Graduate Institute of Electro-Optical and Materials Science, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China); Weng, Hsueh-Ping, E-mail: sherry.weng7949@gmail.com [Graduate Institute of Electro-Optical and Materials Science, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China); Hsu, Jyun-Jheng, E-mail: k88520x@gmail.com [Graduate Institute of Electro-Optical and Materials Science, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China); Yu, Hsin Her, E-mail: hhyu@nfu.edu.tw [Department of Biotechnology, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China)

2016-04-15

Polystyrene (PS) microspheres were synthesized by emulsifier-free emulsion polymerization and arranged in an array of closely packed, opal-like photonic crystals by slow self-assembly through dip-coating. This periodic array of PS microspheres was then employed as a rapid qualitative sensor for methanol and ethanol. Both solvents could be detected rapidly based on the routes of their reflection coordinates in the chromaticity diagram or directly by the naked eye on the basis of the change in color within 1 min once a solvent sample had been placed on the PS photochromic sensor. This opal-like PS sensor can thus not only be employed as a rapid sensor for methanol and ethanol but can also be used as a powerful tool for the fast screening of illicit drugs and toxic chemicals during forensic investigations. - Highlights: • Opal-like array of polystyrene (PS) microspheres is synthesized by self-assembly. • This periodic PS array is used as a rapid sensor for methanol and ethanol. • Solvents are detected by routes of reflection coordinates in chromaticity diagram. • They are also detected directly by naked eye based on change in color of sensor. • The color change is irreversible for methanol but reversible for ethanol.

Comparison of solidification of floating drop and homogenous liquid-liquid microextractions for the extraction of two plasticizers from the water kept in PET-bottles.

Science.gov (United States)

Yamini, Yadollah; Ghambarian, Mahnaz; Khalili-Zanjani, Mohammad Reza; Faraji, Mohammad; Shariati, Shahab

2009-09-01

Two approaches based on solidification of floating drop microextraction (SFDME) and homogenous liquid-liquid microextraction (HLLE) were compared for the extraction and preconcentration of di-(2-ethylhexyl) phthalate (DEHP) and di-(2-ethylhexyl) adipate (DEHA) from the mineral water samples. In SFDME, a floated drop of the mixture of acetophenone/1-undecanol (1:8) was exposed on the surface of the aqueous solution and extraction was permitted to occur. In HLLE, a homogenous ternary solvent system was used by water/methanol/chloroform and the phase separation phenomenon occurred by salt addition. Under the optimal conditions, the LODs for the two target plasticizers (DEHA and DEHP), obtained by SFDME-GC-FID and HLLE-GC-FID, were ranged from 0.03 to 0.01 microg/L and 0.02 to 0.01 microg/L, respectively. HLLE provided higher preconcentration factors (472.5- and 551.2-fold) within the shorter extraction time as well as better RSDs (4.5-6.9%). While, in SFDME, high preconcentration factors in the range of 162-198 and good RSDs in the range of 5.2-9.6% were obtained. Both methods were applied for the analysis of two plasticizers in different water samples and two target plasticizers were found in the bottled mineral water after the expiring time and the boiling water was exposed to a polyethylene vial.

The effect of non-aqueous solvents on spectrophotometric analysis of lead (II)

International Nuclear Information System (INIS)

Ramadan, A.A.; Bahbouh, M.; Kamuah, M.

1992-01-01

The effect of the following non-aqueous solvents: Methanol, Ethanol, Propanol, iso-propanol, dimethylsulfoxide, dimethylformamide and acetonitrile on spectrophotometric analysis of lead (II) was studied. One absorption peak at range 220-340 nm was observed. The values of maximum wave length (λ max ) and maximum molar absorptivity coefficient (ε max ) vary in accordance with the above solvents and the concentration of HC1. the analytical curves, A=f(C Pb 2+ ), for the determination of lead (II) in presence 5 M HC1 (in methanol) and 7 M HC1 (in other solvents) showed linear proportionality over the concentration range 2.5x10 -5 - 2.0x10 -4 M Pb 2+ . (author). 16 Refs., 4 figs., 2 Tabs

Photodegradation of bifenthrin and deltamethrin-effect of copper amendment and solvent system.

Science.gov (United States)

Tariq, Saadia Rashid; Ahmed, Dildar; Farooq, Amna; Rasheed, Sonia; Mansoor, Mubarkah

2017-02-01

The photodegradation of bifenthrin and deltamethrin was studied in the presence of Cu salts and two different solvents, methanol and acetonitrile. Results of the study showed that in the absence of any metal salt, the two pesticides degraded more rapidly in acetonitrile than in methanol. After 24 h of UV irradiation, 70% of deltamethrin had degraded in acetonitrile, while only 41% bifenthrin degraded in this solvent. In methanol, bifenthrin degraded at a much enhanced rate than in acetonitrile while the rate of degradation of deltamethrin was comparable to that in acetonitrile. The photodegradation was further enhanced by the addition of copper to the solution of bifenthrin and deltamethrin in acetonitrile. The rate of photodegradation of deltamethrin increased from 2.4 × 10 -2 to 3.5 × 10 -2  h -1 in acetonitrile and 2.5 × 10 -2 to 3.4 × 10 -2  h -1 in methanol after the addition of copper. Similarly, the rate of photodegradation of bifenthrin was increased from 5.0 × 10 -3 to 9.0 × 10 -3  h -1 in acetonitrile and 7.0 × 10 -3 to 9.05 × 10 -3  h -1 in methanol with the addition of copper. Thus, copper has the potential to enhance the photodegradation of bifenthrin and deltamethrin in both the solvents.

Modelling and experimental studies on a direct methanol fuel cell working under low methanol crossover and high methanol concentrations

Energy Technology Data Exchange (ETDEWEB)

Oliveira, V.B.; Pinto, A.M.F.R. [Centro de Estudos de Fenomenos de Transporte, Departamento de Eng. Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Rangel, C.M. [Instituto Nacional de Energia e Geologia, Fuel Cells and Hydrogen, Estrada do Paco do Lumiar, 1649-038 Lisboa (Portugal)

2009-08-15

A number of issues need to be resolved before DMFC can be commercially viable such as the methanol crossover and water crossover which must be minimised in portable DMFCs. The main gain of this work is to systematically vary commercial MEA materials and check their influence on the cell performance of a direct methanol fuel cell operating at close to room temperature. A detailed experimental study on the performance of an <> developed DMFC with 25 cm{sup 2} of active membrane area, working near the ambient conditions is described. Tailored MEAs (membrane-electrode assemblies), with different structures and combinations of gas diffusion layers (GDLs), were designed and tested in order to select optimal working conditions at high methanol concentration levels without sacrificing performance. The experimental polarization and power density curves were successfully compared with the predictions of a steady state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in the DMFC recently developed by the same authors. The influence of the anode gas diffusion layer media, the membrane thickness and the MEA properties on the cell performance are explained under the light of the predicted methanol crossover rate across the membrane. A tailored MEA build-up with the common available commercial materials was proposed to achieve relatively low methanol crossover, operating at high methanol concentrations. The use of adequate materials for the gas diffusion layers (carbon paper at the anode GDL and carbon cloth at the cathode GDL) enables the use of thinner membranes enhancing the water back diffusion which is essential to work at high methanol concentrations. (author)

Sub/supercritical carbon dioxide induced phase switching for the reaction and separation in ILs/methanol

Directory of Open Access Journals (Sweden)

Jiayu Xin

2016-07-01

Full Text Available Separation of products from ionic liquid (IL solvents is one of the main challenges that hinder their utilizations. In this study, the production of γ-valerolactone (GVL by selective hydrogenation of α-angelica lactone (AL and separation of the products from the IL solvent were carried out by using subcritical CO2 as a “switch” at room temperature. After the mixture was separated into two phases by subcritical CO2, AL and nano Pd/C catalyst were only found in the lower IL-rich phase, GVL was produced with quantitative yield and enriched in the upper methanol-rich phase. Pure GVL can be obtained by depressurizing to release CO2 and evaporation to remove methanol of the upper phase, the lower phase containing IL, catalyst and methanol can be recycled for the next reaction. The strategy may provide a new approach to produce and separate products from IL solvents at mild conditions. Keywords: Separation, Ionic liquids, Selective hydrogenation, Mild condition, Subcritical CO2

Measurement and correlation of solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in seven solvents at different temperatures

International Nuclear Information System (INIS)

Xiao Min; Shao Yundong; Yan Weidong; Zhang Zizhang

2011-01-01

The solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in water, methanol, ethanol, 1-propanol, 1-butanol, acetone, and ethyl acetate from T = (288.2 to 328.2) K were measured. The solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in selected solvents increase with increasing temperature, respectively. The experimental solubility data were correlated by a simplified thermodynamic equation and a three-parameter empirical equation.

Isolation Of Compounds Of Steroids Teripang Gamat (Stichopus variegatus With Various Types Of Solvents

Directory of Open Access Journals (Sweden)

Meydia Meydia

2016-12-01

Full Text Available Sea cucumber is one of the fisheries commodity that has an important economic value. Generally istraded in dried form (beche-de-mer. One of thebioactive substances contained in sea cucumber is steroidcompounds that serves as an aphrodisiac and sex reversal. The purpose of this study was to extract thesteroid of the gamma sea cucumber by using three types of solvents (methanol, ethyl acetate and hexaneand get the best solvent in producing the highest yield of the steroids. The study revealed that steroid ofgamma sea cucumber (Stichopus variegatus dissolved completely ethyl acetate (semi-polar solvent duringthe first phase, second phase and the third phase of extraction. In the methanol (polar solvent steroids onlydissolved in the first extraction phase, while using the hexane (non polar solvent steroid was undetectable.Fractionation by thin layer chromatography was obtained two fractions that identified as cholesterol (Rf =0.96 and testosterone (Rf = 0.91.

Lithium isotope effects in cation exchange chromatography of lithium lactate in water-dimethyl sulfoxide and water-acetone mixed solvent media

International Nuclear Information System (INIS)

Oi, Takao; Kondoh, Akiko; Ohno, Etsuko; Hosoe, Morikazu

1993-01-01

Lithium isotope separation by ion exchange displacement chromatography of lithium lactate in water-dimethyl sulfoxide (DMSO) and water-acetone mixed solvent media at 25 C was explored. In both the water-DMSO and water-acetone system, the single stage isotope separation factor (S) was a convex function of the mixing ratio of the solvents in the external solution phase; S had its maximum value of 1.00254 at water: DMSO=25:75 v/v and 1.00182 at water: acetone=75:25 v/v. Strong correlations of S with solvent partitions between the solution and the exchanger phases were found in both systems, which was qualitatively explainable by considering the lithium isotope distributions between the two phases based on the fundamental lithium isotope effects and the relative affinities of water, DMSO and acetone towards the lithium ion. (orig.)

Experimental Validation of Methanol Crossover in a Three-dimensional, Two-Fluid Model of a Direct Methanol Fuel Cell

DEFF Research Database (Denmark)

Olesen, Anders Christian; Berning, Torsten; Kær, Søren Knudsen

2012-01-01

A fully coupled three-dimensional, steady-state, two-fluid, multi-component and non-isothermal DMFC model has been developed in the commercial CFD package CFX 13 (ANSYS inc.). It accounts for the presence of micro porous layers, non-equilibrium phase change, and methanol and water uptake...... in the ionomer phase of the catalytic layer, and detailed membrane transport of methanol and water. In order to verify the models ability to predict methanol crossover, simulation results are compared with experimental measurements under different current densities along with air and methanol stoichiometries....... Methanol crossover is indirectly measured based on the combined anode and cathode exhaust CO2 mole fraction and by accounting for the CO2 production at the anode as a function of current density. This approach is simple and assumes that all crossed over methanol is oxidized. Moreover, it takes CO2...

Aquadipicrato(tetraethylene glycolgadolinium(III picrate methanol hemisolvate

Directory of Open Access Journals (Sweden)

Hoong-Kun Fun

2008-09-01

Full Text Available The asymmetric unit of the title compound [systematic name: aquabis(2,4,6-trinitrophenolato(3,6,9-trioxaundecane-1,11-diolgadolinium(III 2,4,6-trinitrophenolate methanol hemisolvate], [Gd(C6H2N3O72(C8H18O5(H2O](C6H2N3O7·0.5CH4O, contains two crystallographically independent GdIII complex cations with two uncoordinated picrate anions and one methanol molecule. Each GdIII atom has nine coordination sites occupied by five O atoms of tetraethylene glycol as a pentadentate ligand, one O atom of a water molecule and three O atoms of the two picrate anions as bidentate and monodentate ligands. The geometry is distorted tricapped trigonal prismatic. The mean planes of the two coordinated mono- and bidentate picrate ligands to the GdIII center are almost perpendicular to each other, as indicated by the dihedral angles of 89.92 (8 and 86.60 (8° in the two complex cations. The ions are arranged in a two-dimensional network parallel to the ac plane. Short O...O and N...O contacts between the nitro groups, intramolecular C—H...O hydrogen bonds, intermolecular O—H...O, O—H...N and C—H...O hydrogen bonds, and two π–π interactions between benzene rings [centroid–centroid distances = 3.8073 (10–3.9831 (10 Å] are observed. The methanol solvent molecule is disordered over two positions, with site-occupancy factors of ca 0.6 and 0.4.

Adsorption of methanol, ethanol and water on well-characterized PtSn surface alloys

Science.gov (United States)

Panja, Chameli; Saliba, Najat; Koel, Bruce E.

1998-01-01

Adsorption and desorption of methanol (CH 3OH), ethanol (C 2H 5OH) and water on Pt(111) and two, ordered, PtSn alloys has been studied primarily using temperature-programmed desorption (TPD) mass spectroscopy. The two alloys studied were the {p(2 × 2) Sn}/{Pt(111) } and (√3 × √3) R30° {Sn}/{Pt(111) } surface alloys prepared by vapor deposition of Sn on Pt(111), with θSn = 0.25 and 0.33, respectively. All three molecules are weakly bonded and reversibly adsorbed under UHV conditions on all three surfaces, molecularly desorbing during TPD without any decomposition. The two PtSn surface alloys were found to chemisorb both methanol and ethanol slightly more weakly than on the Pt(111) surface. The desorption activation energies measured by TPD, and hence the adsorption energies, of both methanol and ethanol progressively decrease as the surface concentration of Sn increases, compared with Pt(111). The decreased binding energy leads one to expect a lower reactivity for these alcohols on the two alloys. The sticking coefficients and the monolayer coverages of these alcohols on the two alloys were identical to that on Pt(111) at 100 K, independent of the amount of Sn present in the surface layer. Alloying Sn in Pt(111) also slightly weakens the adsorption energy of water. Water clusters are formed even at low coverages on all three surfaces, eventually forming a water bilayer prior to the formation of a condensed ice phase. These results are relevant to a molecular-level explanation for the reactivity of Sn-promoted Pt surfaces that have been used in the electro-oxidation of simple organic molecules.

Effects of solvent evaporation on water sorption/solubility and nanoleakage of adhesive systems.

Science.gov (United States)

Chimeli, Talita Baumgratz Cachapuz; D'Alpino, Paulo Henrique Perlatti; Pereira, Patrícia Nóbrega; Hilgert, Leandro Augusto; Di Hipólito, Vinicius; Garcia, Fernanda Cristina Pimentel

2014-01-01

To evaluate the influence of solvent evaporation in the kinetics of water diffusion (water sorption-WS, solubility-SL, and net water uptake) and nanoleakage of adhesive systems. Disk-shaped specimens (5.0 mm in diameter x 0.8 mm in thickness) were produced (N=48) using the adhesives: Clearfil S3 Bond (CS3)/Kuraray, Clearfil SE Bond - control group (CSE)/Kuraray, Optibond Solo Plus (OS)/Kerr and Scotchbond Universal Adhesive (SBU)/3M ESPE. The solvents were either evaporated for 30 s or not evaporated (N=24/per group), and then photoactivated for 80 s (550 mW/cm2). After desiccation, the specimens were weighed and stored in distilled water (N=12) or mineral oil (N=12) to evaluate the water diffusion over a 7-day period. Net water uptake (%) was also calculated as the sum of WS and SL. Data were submitted to 3-way ANOVA/Tukey's test (α=5%). The nanoleakage expression in three additional specimens per group was also evaluated after ammoniacal silver impregnation after 7 days of water storage under SEM. Statistical analysis revealed that only the factor "adhesive" was significant (padhesives. CSE (control) presented significantly lower net uptake (5.4%). The nanoleakage was enhanced by the presence of solvent in the adhesives. Although the evaporation has no effect in the kinetics of water diffusion, the nanoleakage expression of the adhesives tested increases when the solvents are not evaporated.

EVALUATION OF SOLVENTS EFFICIENCY IN CONDENSATE BANKING REMOVAL

OpenAIRE

CORREA, TOMAS; TIAB, DJEBBAR; RESTREPO, DORA PATRICIA

2009-01-01

This work describes experimental design and tests performed to simulate gas condensate reservoir conditions below dew point in the laboratory using three different compositions of synthetic gas condensate. Methanol, propanol and methylene chloride are the solvents used to remove the condensate banking and improve the gas effective permeability near to the wellbore. Solvents are injected in Berea sandstone rock with similar petrophysical properties in order to compare the efficiency at removin...

Hydrophobic deep eutectic solvents as water-immiscible extractants

NARCIS (Netherlands)

Osch, van D.J.G.P.; Zubeir, L.F.; Bruinhorst, van den A.; Alves da Rocha, M.A.; Kroon, M.C.

2015-01-01

Hydrophobic deep eutectic solvents (DESs) are presented for the first time. They consist of decanoic acid and various quaternary ammonium salts. The effect of the alkyl chains on the hydrophobicity and the equilibrium of the two-phase DES–water system were investigated. These new DESs were

The influence of water on the oxygen-silver interaction and on the oxidative dehydrogenation of methanol

NARCIS (Netherlands)

Lefferts, Leon; Van Ommen, Jan G.; Ross, Julian R H

1988-01-01

Experiments carried out using temperature-programmed desorption and reduction could detect no interaction between water and silver at 200 °C. However, separate experiments on the effect of water on the oxidative dehydrogenation of methanol over a silver catalyst showed that water affected the

Integrated anode structure for passive direct methanol fuel cells with neat methanol operation

Science.gov (United States)

Wu, Huijuan; Zhang, Haifeng; Chen, Peng; Guo, Jing; Yuan, Ting; Zheng, Junwei; Yang, Hui

2014-02-01

A microporous titanium plate based integrated anode structure (Ti-IAS) suitable for passive direct methanol fuel cells (DMFCs) fueled with neat methanol is reported. This anode structure incorporates a porous titanium plate as a methanol mass transfer barrier and current collector, pervaporation film for passively vaporizing methanol, vaporous methanol cavity for evenly distributing fuel, and channels for carbon dioxide venting. With the effective control of methanol delivery rate, the Ti-IAS based DMFC allows the direct use of neat methanol as the fuel source. In the meantime, the required water for methanol-oxidation reaction at the anode can also be fully recovered from the cathode with the help of the highly hydrophobic microporous layer in the cathode. DMFCs incorporating this new anode structure exhibit a power density as high as 40 mW cm-2 and a high volumetric energy density of 489 Wh L-1 operating with neat methanol and at 25 °C. Importantly, no obvious performance degradation of the passive DMFC system is observed after more than 90 h of continuous operation. The experimental results reveal that the compact DMFC based on the Ti-IAS exhibits a substantial potential as power sources for portable applications.

The Methanol Economy Project

Energy Technology Data Exchange (ETDEWEB)

Olah, George [Univ. of Southern California, Los Angeles, CA (United States); Prakash, G. K. [Univ. of Southern California, Los Angeles, CA (United States)

2014-02-01

The Methanol Economy Project is based on the concept of replacing fossil fuels with methanol generated either from renewable resources or abundant natural (shale) gas. The full methanol cycle was investigated in this project, from production of methanol through bromination of methane, bireforming of methane to syngas, CO₂ capture using supported amines, co-electrolysis of CO₂ and water to formate and syngas, decomposition of formate to CO₂ and H₂, and use of formic acid in a direct formic acid fuel cell. Each of these projects achieved milestones and provided new insights into their respective fields.

“Bligh and Dyer” and Folch Methods for Solid–Liquid–Liquid Extraction of Lipids from Microorganisms. Comprehension of Solvatation Mechanisms and towards Substitution with Alternative Solvents

Directory of Open Access Journals (Sweden)

Cassandra Breil

2017-03-01

Full Text Available Bligh and Dyer (B & D or Folch procedures for the extraction and separation of lipids from microorganisms and biological tissues using chloroform/methanol/water have been used tens of thousands of times and are “gold standards” for the analysis of extracted lipids. Based on the Conductor-like Screening MOdel for realistic Solvatation (COSMO-RS, we select ethanol and ethyl acetate as being potentially suitable for the substitution of methanol and chloroform. We confirm this by performing solid–liquid extraction of yeast (Yarrowia lipolytica IFP29 and subsequent liquid–liquid partition—the two steps of routine extraction. For this purpose, we consider similar points in the ternary phase diagrams of water/methanol/chloroform and water/ethanol/ethyl acetate, both in the monophasic mixtures and in the liquid–liquid miscibility gap. Based on high performance thin-layer chromatography (HPTLC to obtain the distribution of lipids classes, and gas chromatography coupled with a flame ionisation detector (GC/FID to obtain fatty acid profiles, this greener solvents pair is found to be almost as effective as the classic methanol–chloroform couple in terms of efficiency and selectivity of lipids and non-lipid material. Moreover, using these bio-sourced solvents as an alternative system is shown to be as effective as the classical system in terms of the yield of lipids extracted from microorganism tissues, independently of their apparent hydrophilicity.

Optimal Concentration of Organic Solvents to be Used in the Broth Microdilution Method to Determine the Antimicrobial Activity of Natural Products Against Paenibacillus Larvae

Directory of Open Access Journals (Sweden)

Cugnata Noelia Melina

2017-06-01

Full Text Available American Foulbrood (AFB is a bacterial disease, caused by Paenibacillus larvae, that affects honeybees (Apis mellifera. Alternative strategies to control AFB are based on the treatment of the beehives with antimicrobial natural substances such as extracts, essential oils and/or pure compounds from plants, honey by-products, bacteria and moulds. The broth microdilution method is currently one of the most widely used methods to determine the minimum inhibitory concentration (MIC of a substance. In this regard, the fact that most natural products, due to their lipophilic nature, must be dissolved in organic solvents or their aqueous mixtures is an issue of major concern because the organic solvent becomes part of the dilution in the incubation medium, and therefore, can interfere with bacterial viability depending on its nature and concentration. A systematic study was carried out to determine by the broth microdilution method the MIC and the maximum non inhibitory concentration (MNIC against P. larvae of the most common organic solvents used to extract or dissolve natural products, i.e. ethanol, methanol, acetonitrile, n-butanol, dimethylsulfoxide, and acidified hydromethanolic solutions. From the MIC and MNIC for each organic solvent, recommended maximum concentrations in contact with P. larvae were established: DMSO 5% (v/v, acetonitrile 7.5% (v/v, ethanol 7.5% (v/v, methanol 12% (v/v, n-butanol 1% (v/v, and methanol-water-acetic acid (1.25:98.71:0.04, v/v/v.

Structure and spectroscopic properties of N,S-coordinating 2-methyl-sulfanyl-N-[(1H-pyrrol-2-yl)methyl-idene]aniline methanol monosolvate.

Science.gov (United States)

Richards, D Douglas; Ang, M Trisha C; McDonald, Robert; Bierenstiel, Matthias

2015-10-01

The reaction of pyrrole-2-carboxaldehyde and 2-(methyl-sulfan-yl)aniline in refluxing methanol gave an olive-green residue in which yellow crystals of the title compound, C12H12N2S·CH3OH, were grown from slow evaporation of methanol at 263 K. In the crystal, hydrogen-bonding inter-actions link the aniline mol-ecule and a nearby methanol solvent mol-ecule. These units are linked by a pair of weak C-H⋯Omethanol interactions, forming inversion dimers consisting of two main molecules and two solvent molecules.

Cycloadditions in mixed aqueous solvents : the role of the water concentration

NARCIS (Netherlands)

Rispens, Theo; Engberts, Jan B. F. N.

We examined the kinetics of a series of cycloaddition reactions in mixtures of water with methanol, acetonitrile and poly(ethylene glycol) (MW 1000). The reactions include the Diels-Alder (DA) reaction between cyclopentadiene and N-n-butylmaleimide or acridizinium bromide, the retro-Diels-Alder

Fluorescence spectroscopy of Rhodamine 6G: concentration and solvent effects.

Science.gov (United States)

Zehentbauer, Florian M; Moretto, Claudia; Stephen, Ryan; Thevar, Thangavel; Gilchrist, John R; Pokrajac, Dubravka; Richard, Katherine L; Kiefer, Johannes

2014-01-01

Rhodamine 6G (R6G), also known as Rhodamine 590, is one of the most frequently used dyes for application in dye lasers and as a fluorescence tracer, e.g., in the area of environmental hydraulics. Knowing the spectroscopic characteristics of the optical emission is key to obtaining high conversion efficiency and measurement accuracy, respectively. In this work, solvent and concentration effects are studied. A series of eight different organic solvents (methanol, ethanol, n-propanol, iso-propanol, n-butanol, n-pentanol, acetone, and dimethyl sulfoxide (DMSO)) are investigated at constant dye concentration. Relatively small changes of the fluorescence spectrum are observed for the different solvents; the highest fluorescence intensity is observed for methanol and lowest for DMSO. The shortest peak wavelength is found in methanol (568 nm) and the longest in DMSO (579 nm). Concentration effects in aqueous R6G solutions are studied over the full concentration range from the solubility limit to highly dilute states. Changing the dye concentration provides tunability between ∼550 nm in the dilute case and ∼620 nm at high concentration, at which point the fluorescence spectrum indicates the formation of R6G aggregates. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of real-time measurement of methanol-concentration in polymer electrolyte membrane using a local NMR sensor

International Nuclear Information System (INIS)

Ogawa, Kuniyasu; Ito, Kohei; Haishi, Tomoyuki

2007-01-01

A real-time sensor to measure methanol concentration in polymer electrolyte membrane (PEM) was developed for reducing methanol cross-over in Direct Methanol Fuel Cell (DMFC). The principle of the methanol sensor is based on the chemical shift of CH and OH species under high magnetic field. The sensor consists of a planar surface coil of 1.3 mm outside diameter. NMR signal from PEM being exposed to CH3OH solvent was measured using NMR sensor. Time-dependence changes of methanol concentration in PEM were obtained from analyzing spectrum of NMR signal. (author)

Biodiesel synthesis by direct transesterification of microalga Botryococcus braunii with continuous methanol reflux.

Science.gov (United States)

Hidalgo, Pamela; Ciudad, Gustavo; Schober, Sigurd; Mittelbach, Martin; Navia, Rodrigo

2015-04-01

Direct transesterification of Botryococcus braunii with continuous acyl acceptor reflux was evaluated. This method combines in one step lipid extraction and esterification/transesterification. Fatty acid methyl esters (FAME) synthesis by direct conversion of microalgal biomass was carried out using sulfuric acid as catalyst and methanol as acyl acceptor. In this system, once lipids are extracted, they are contacted with the catalyst and methanol reaching 82%wt of FAME yield. To optimize the reaction conditions, a factorial design using surface response methodology was applied. The effects of catalyst concentration and co-solvent concentration were studied. Hexane was used as co-solvent for increasing lipid extraction performance. The incorporation of hexane in the reaction provoked an increase in FAME yield from 82% (pure methanol) to 95% when a 47%v/v of hexane was incorporated in the reaction. However, the selectivity towards non-saponifiable lipids such as sterols was increased, negatively affecting biodiesel quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extraction of Betulin, Trimyristin, Eugenol and Carnosic Acid Using Water-Organic Solvent Mixtures

Directory of Open Access Journals (Sweden)

Fulgentius N. Lugemwa

2012-08-01

Full Text Available A solvent system consisting of ethyl acetate, ethyl alcohol and water, in the volume ratio of 4.5:4.5:1, was developed and used to extract, at room temperature, betulin from white birch bark and antioxidants from spices (rosemary, thyme, sage, and oregano and white oak chips. In addition, under reflux conditions, trimyristin was extracted from nutmeg using the same solvent system, and eugenol from olives was extracted using a mixture of salt water and ethyl acetate. The protocol demonstrates the use of water in organic solvents to extract natural products from plants. Measurement of the free-radical scavenging activity using by 2,2-diphenyl-1-picrylhydrazyl (DPPH indicated that the extraction of plant material using ethyl acetate, ethyl alcohol and water (4.5:4.5:1, v/v/v was exhaustive when carried out at room temperature for 96 h.

Singlet oxygen reactivity in water-rich solvent mixtures

Directory of Open Access Journals (Sweden)

Cristina Sousa

2008-01-01

Full Text Available The 3-methylindole (3MI oxygenation sensitized by psoralen (PSO has been investigated in 100%, 20% and 5% O2-saturated water/dioxane (H2O/Dx mixtures. The lowering of the ¹O2* chemical rate when water (k chem∆3MI = 1.4 × 109 M-1 s-1 is replaced by deuterated water (k chem∆3MI = 1.9 × 108 M-1 s-1 suggests that hydrogen abstraction is involved in the rate determining step. A high dependence of the chemical rate constant on water concentration in H2O/Dx mixtures was found showing that water molecules are absolutely essential for the success of the 3MI substrate oxidation by ¹O2* in water-rich solvent mixtures.

Isolation Of Compounds Of Steroids Teripang Gamat (Stichopus variegatus With Various Types Of Solvents

Directory of Open Access Journals (Sweden)

Meydia Meydia

2017-02-01

Full Text Available AbstractSea cucumber is one of the fisheries commodity that has an important economic value. Generally is traded in dried form (beche-de-mer. One of thebioactive substances contained in sea cucumber is steroid compounds that serves as an aphrodisiac and sex reversal. The purpose of this study was to extract the steroid of the gamma sea cucumber by using three types of solvents (methanol, ethyl acetate and hexane and get the best solvent in producing the highest yield of the steroids. The study revealed that steroid of gamma sea cucumber (Stichopus variegatus dissolved completely ethyl acetate (semi-polar solvent during the first phase, second phase and the third phase of extraction. In the methanol (polar solvent steroids only dissolved in the first extraction phase, while using the hexane (non polar solvent steroid was undetectable. Fractionation by thin layer chromatography was obtained two fractions that identified as cholesterol (Rf = 0.96 and testosterone (Rf = 0.91.

Rational approach to solvent system selection for liquid-liquid extraction-assisted sample pretreatment in counter-current chromatography.

Science.gov (United States)

Wang, Jiajia; Gu, Dongyu; Wang, Miao; Guo, Xinfeng; Li, Haoquan; Dong, Yue; Guo, Hong; Wang, Yi; Fan, Mengqi; Yang, Yi

2017-05-15

A rational liquid-liquid extraction approach was established to pre-treat samples for high-speed counter-current chromatography (HSCCC). n-Hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) and (1:5:1:5, v/v) were selected as solvent systems for liquid-liquid extraction by systematically screening K of target compounds to remove low- and high-polarity impurities in the sample, respectively. After liquid-liquid extraction was performed, 1.4g of crude sample II was obtained from 18.5g of crude sample I which was extracted from the flowers of Robinia pseudoacacia L., and then separated with HSCCC by using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v). As a result, 31mg of robinin and 37mg of kaempferol 7-O-α-l-rhamnopyranoside were isolated from 200mg of crude sample II in a single run of HSCCC. A scale-up separation was also performed, and 160mg of robinin with 95% purity and 188mg of kaempferol 7-O-α-l-rhamnopyranoside with 97% purity were produced from 1.2g of crude sample II. Copyright © 2017 Elsevier B.V. All rights reserved.

Solvents effects on crystallinity and dissolution of β-artemether.

Science.gov (United States)

Xu, Jianghui; Singh, Vikramjeet; Yin, Xianzhen; Singh, Parbeen; Wu, Li; Xu, Xiaonan; Guo, Tao; Sun, Lixin; Gui, Shuangying; Zhang, Jiwen

2017-03-01

β-artemether (ARM) is a widely used anti-malarial drug isolated from the Chinese antimalarial plant, Artemisia annua. The solvent effects on crystal habits and dissolution of ARM were thoroughly investigated and discussed herein. The ARM was recrystallized in nine different solvents of varied polarity, namely, methanol, ethanol, isopropanol, tetrahydrofuran, dichloromethane, trichloromethane, ethyl acetate, acetone and hexane by solvent evaporation method. The obtained crystals were morphologically characterized using scanning electron microscope (SEM). The average sizes of crystals were 1.80-2.64 μm calculated from microscopic images using Image-Pro software. No significant change in chemical structure was noticed after recrystallization and the specific band at 875 cm -1 wavenumber (C-O-O-C) confirmed the presence of most sensitive functional group in the ARM chemical structure. The existence and production of two polymorphic forms, polymorph A and polymorph B, was confirmed by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). The data suggested that the fabrication of polymorph B can be simply obtained from the recrystallization of ARM in a specific solvent. Significant effects of solvent polarity, crystals shapes and sizes on drug dissolution were noticed during in vitro dissolution test. The release kinetics were calculated and well fitted by the Higuchi and Hixon-Crowell models. The ARM-methanol and ARM-hexane showed highest and slowest dissolution, respectively, due to the effects of solvent polarity and crystal morphologies. Overall, proper selection of the solvents for the final crystallization of ARM helps to optimize dissolution and bioavailability for a better delivery of anti-malarial drug.

Preferential solvation of ions in mixed solvents. 6: Univalent anions in aqueous organic solvents according to the inverse Kirkwood-Buff integral (IKBI) approach

Energy Technology Data Exchange (ETDEWEB)

Marcus, Yizhak [Department of Inorganic and Analytical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)], E-mail: ymarcus@vms.huji.ac.il

2007-10-15

The inverse Kirkwood-Buff integral (IKBI) approach is applied to the preferential solvation of F{sup -}, Cl{sup -}, Br{sup -}, I{sup -}, and ClO{sub 4}{sup -} in aqueous mixtures of the co-solvents (S) methanol (MeOH), ethanol (EtOH), t-butanol (t-BuOH), 1,2-ethanediol (EG), glycerol (Gly), acetone (Me{sub 2}CO), acetonitrile (MeCN), formamide (FA), N,N-dimethylformamide (DMF), N,N,N',N',N'',N''-hexamethyl phosphoric triamide (HMPT), and dimethylsulfoxide (DMSO), as far as the relevant data exist in the literature. Fluoride anions are selectively solvated by the water up to large mole fractions (x{sub S} {>=} 0.4) of S = EtOH, t-BuOH, Me{sub 2}CO, MeCN, and DMF, and up to lower contents (x{sub S} {approx} 0.1) of MeOH, EG, FA, and DMSO. The other anions are preferentially solvated by water to diminishing extent as their sizes become larger, and the largest ones show some preference for S in water-rich mixtures of MeOH and FA, whereas in aqueous Gly even chloride is preferentially solvated by the Gly. The competition between the co-solvent and the anion for the hydrogen bonds that water molecules donate is the main cause for the observed preferential solvation behaviour.

The Role of Interfacial Potential in Adsorbate Bonding: Electrode Potential-Dependent Infrared Spectra for Saturated CO Adlayers on Pt(110) and Related Electrochemical Surfaces in Varying Solvent Environments

Science.gov (United States)

1992-05-01

as supporting electrolytes were recrystallized from methanol, water and ethanol , and water, respectively, and dried under vacuum at 110°C. Electrode...under these conditions 8,17 (vide infra). All measurements were performed at room temperature , 23±1*C. RESULTS AND DISCUSSION The experimental strategy...of interferometer scans during a suitably slow (2 mV s- ) positive-going potential sweep. For solvents containing traces of water, electrooxidative

Cold sprayed WO3 and TiO2 electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications.

Science.gov (United States)

Haisch, Christoph; Schneider, Jenny; Fleisch, Manuel; Gutzmann, Henning; Klassen, Thomas; Bahnemann, Detlef W

2017-10-03

Films prepared by cold spray have potential applications as photoanodes in electrochemical water splitting and waste water purification. In the present study cold sprayed photoelectrodes produced with WO 3 (active under visible light illumination) and TiO 2 (active under UV illumination) on titanium metal substrates were investigated as photoanodes for the oxidation of water and methanol, respectively. Methanol was chosen as organic model pollutant in acidic electrolytes. Main advantages of the cold sprayed photoelectrodes are the improved metal-semiconductor junctions and the superior mechanical stability. Additionally, the cold spray method can be utilized as a large-scale electrode fabrication technique for photoelectrochemical applications. Incident photon to current efficiencies reveal that cold sprayed TiO 2 /WO 3 photoanodes exhibit the best photoelectrochemical properties with regard to the water and methanol oxidation reactions in comparison with the benchmark photocatalyst Aeroxide TiO 2 P25 due to more efficient harvesting of the total solar light irradiation related to their smaller band gap energies.

A potentiometric study of (acid+base) equilibria in substituted 4-nitropyridine N-oxide systems in methanol and dimethyl sulfoxide

International Nuclear Information System (INIS)

Gurzynski, Lukasz; Puszko, Aniela; Makowski, Mariusz; Chmurzynski, Lech

2007-01-01

The acid dissociation constants for cationic acids conjugated with 4-nitropyridine N-oxides have been determined using potentiometric titration method. The measurements in the systems of thirteen 4-nitropyridine N-oxide derivatives were carried out in the polar amphiprotic methanol (MeOH) and in the aprotic protophilic dimethyl sulfoxide (DMSO). Likewise as in the polar aprotic protophobic solvents (acetonitrile, acetone) it was found that in MeOH for all N-oxides studied the pK a values were readily determinable, whereas in DMSO the pK a values were hardly determinable or indeterminable by using the potentiometric method. In addition, just like in our previous investigations it was revealed that the sequence of the pK a values of the cationic acids in methanol is the same as in the water and the values are lower than those determined in acetonitrile and acetone. Also, it was found that the phenomenon of cationic homoconjugation equilibria was not present in the systems involving 4-nitropyridine N-oxide derivatives in both solvents used. Furthermore, protonation energies, ΔE prot , and Gibbs free enthalpies, ΔG prot , in vacuo have been compared with acid dissociation constants (expressed as pK a MeOH values) of the protonated N-oxides determined by potentiometric titration in methanol to establish a correlation between these magnitudes

A potentiometric study of (acid+base) equilibria in substituted 4-nitropyridine N-oxide systems in methanol and dimethyl sulfoxide

Energy Technology Data Exchange (ETDEWEB)

Gurzynski, Lukasz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Puszko, Aniela [Department of Organic Chemistry, School of Economics, Wroclaw (Poland); Makowski, Mariusz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, Lech [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail: lech@chemik.chem.univ.gda.pl

2007-02-15

The acid dissociation constants for cationic acids conjugated with 4-nitropyridine N-oxides have been determined using potentiometric titration method. The measurements in the systems of thirteen 4-nitropyridine N-oxide derivatives were carried out in the polar amphiprotic methanol (MeOH) and in the aprotic protophilic dimethyl sulfoxide (DMSO). Likewise as in the polar aprotic protophobic solvents (acetonitrile, acetone) it was found that in MeOH for all N-oxides studied the pK{sub a} values were readily determinable, whereas in DMSO the pK{sub a} values were hardly determinable or indeterminable by using the potentiometric method. In addition, just like in our previous investigations it was revealed that the sequence of the pK{sub a} values of the cationic acids in methanol is the same as in the water and the values are lower than those determined in acetonitrile and acetone. Also, it was found that the phenomenon of cationic homoconjugation equilibria was not present in the systems involving 4-nitropyridine N-oxide derivatives in both solvents used. Furthermore, protonation energies, {delta}E{sub prot}, and Gibbs free enthalpies, {delta}G{sub prot}, in vacuo have been compared with acid dissociation constants (expressed as pK{sub a}{sup MeOH} values) of the protonated N-oxides determined by potentiometric titration in methanol to establish a correlation between these magnitudes.

Why does high pressure destroy co-non-solvency of PNIPAm in aqueous methanol?

Science.gov (United States)

de Oliveira, Tiago E; Netz, Paulo A; Mukherji, Debashish; Kremer, Kurt

2015-11-28

It is well known that poly(N-isopropylacrylamide) (PNIPAm) exhibits an interesting, yet puzzling, phenomenon of co-non-solvency. Co-non-solvency occurs when two competing good solvents for PNIPAm, such as water and alcohol, are mixed together. As a result, the same PNIPAm collapses within intermediate mixing ratios. This complex conformational transition is driven by preferential binding of methanol with PNIPAm. Interestingly, co-non-solvency can be destroyed when applying high hydrostatic pressures. In this work, using a large scale molecular dynamics simulation employing high pressures, we propose a microscopic picture behind the suppression of the co-non-solvency phenomenon. Based on thermodynamic and structural analysis, our results suggest that the preferential binding of methanol with PNIPAm gets partially lost at high pressures, making the background fluid reasonably homogeneous for the polymer. This is consistent with the hypothesis that the co-non-solvency phenomenon is driven by preferential binding and is not based on depletion effects.

Solvent wash solution

International Nuclear Information System (INIS)

Neace, J.C.

1986-01-01

This patent describes a process for removing diluent degradation products from a solvent extraction solution comprising an admixture of an organic extractant for uranium and plutonium and a non-polar organic liquid diluent, which has been used to recover uranium and plutonium from spent nuclear fuel. Comprising combining a wash solution consisting of: (a) water; and (b) a positive amount up to about, an including, 50 volume percent of at least one highly-polar water-miscible organic solvent, based on the total volume of the water and the highly-polar organic solvent, with the solvent extraction solution after uranium and plutonium values have been stripped from the solvent extraction solution, the diluent degradation products dissolving in the highly-polar organic solvent and the extractant and diluent of the extraction solution not dissolving in the highly-polar organic solvent, and separating the highly-polar organic solvent and the extraction solution to obtain a purified extraction solution

Spectral characteristics and colloidal properties of chlorophyll a{prime} in aqueous methanol

Energy Technology Data Exchange (ETDEWEB)

Oba, Toru [Ritsumeikan Univ., Kusatsu (Japan); Mimuro, Mamoru [National Inst. for Basic Biology, Okazaki (Japan); Wang, Z.Y.; Nozawa, Tsunenori [Tohoku Univ., Sendai (Japan); Yoshida, Shoichiro; Watanabe, Tadashi [Univ. of Tokyo (Japan)

1997-04-17

The `phase behavior` of chlorophyll a` (Chl a`, C13{sup 2}-epimer of Chl a) dissolved in aqueous methanol was examined in terms of the composition of the solvent. The study aimed at elucidating the property of Chl a`, the exotic pigment found in a photosynthetic reaction center complex, as well as at clarifying the nature of the Chl aggregation in aqueous media. Visible absorption, circular dichroism (CD), fluorescence and resonance Raman spectroscopies, dynamic light-scattering measurements, and electron microscopy were utilized. Chl a` formed either of two types of colloids depending on the solvent composition. The one formed over a wide methanol volume percentage (ca. 73-30%) commonly possessed a single microscopic structural unit that yielded the double-peaked absorption (ca. 690 and 715 nm) accompanied by a symmetric dispersed-type CD spectrum. Increasing methanol concentration within this solvent composition range enhanced the size of the colloid and finally caused critical opalescence, which was reminiscent of the critical behavior of the aqueous solution of nonionic surfactants. These findings indicate that the microscopic structure of the Chl a` aggregate was independent of the size and shape of the colloid. The difference between the aggregation behaviors of Chl a and a` suggests a narrower choice of possible molecular arrangements in the Chl a` aggregate as an inherent property of the pigment. 37 refs., 11 figs.

A study of photon interaction parameters in some commonly used solvents

International Nuclear Information System (INIS)

Singh, Tejbir; Kaur, Paramjeet; Singh, Parjit S

2007-01-01

Various parameters of dosimetric interest such as mass attenuation coefficients, effective atomic numbers and electron densities of some commonly used solvents such as acetonitrile (C 4 H 3 N), butanol (C 4 H 9 OH), chlorobenzene (C 6 H 5 Cl), diethylether (C 4 H 10 O), ethanol (C 2 H 5 OH), methanol (CH 3 OH), propanol (C 3 H 7 OH) and water (H 2 O) were computed in the wide energy range of 10 keV-100 GeV. A comparative study of two different methods used to compute effective atomic numbers has been done. It is observed that in the intermediate energy region (0.1-5 MeV), the mass attenuation coefficient values becomes almost the same for all the solvents, and the effective atomic number and electron density show almost constant values, whereas significant variation is observed in both lower (10-100 keV) and higher (5 MeV-100 GeV) energy regions for all the solvents, which may be due to the dominance of different partial interaction processes in different energy regions

A selective electrocatalyst-based direct methanol fuel cell operated at high concentrations of methanol.

Science.gov (United States)

Feng, Yan; Liu, Hui; Yang, Jun

2017-06-01

Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag 2 S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm -2 at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol.

A selective electrocatalyst–based direct methanol fuel cell operated at high concentrations of methanol

Science.gov (United States)

Feng, Yan; Liu, Hui; Yang, Jun

2017-01-01

Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag2S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm−2 at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol. PMID:28695199

Preparative Separation of Phenolic Compounds from Halimodendron halodendron by High-Speed Counter-Current Chromatography

OpenAIRE

Wang, Jihua; Gao, Haifeng; Zhao, Jianglin; Wang, Qi; Zhou, Ligang; Han, Jianguo; Yu, Zhu; Yang, Fuyu

2010-01-01

Three phenolic compounds, p-hydroxybenzoic acid (1), isorhamnetin-3-O-β-D-rutinoside (2), and 3,3'-di-O-methylquercetin (5), along with a phenolic mixture were successfully separated from the ethyl acetate crude extract of Halimodendron halodendron by high-speed counter-current chromatography (HSCCC) with chloroform-methanol-water-acetic acid (4:3:2:0.05, v/v) as the two-phase solvent system. The phenolic mixture from HSCCC was further separated by preparative HPLC and purified by Sephadex LH...

Study on the conditions of methanol use as a secondary refrigerant; Etude sur les conditions d'utilisation du methanol comme refrigerant secondaire

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-11-01

This study examined the advantages and safe use of a water and methanol solution for use in a piped cooling network in skating rinks. A methanol/water solution offers simple repair solutions for leaks under ice, because unlike brine, it does not leave spots or soften the ice. The solution is less corrosive than brine and offers efficient heat transfer in heat exchangers. The standards and regulations that apply to the methanol/water solution were outlined. The following preventive measures are recommended to minimize risk associated with methanol in skating rinks: solutions should be diluted to 25 per cent methanol to avoid storing and handling of more concentrated products; methanol vapour detectors should be installed in service rooms where spills may occur; respiratory and protective eye protection should be available in service rooms; and, protection should be provided against freezing when the product is circulated outside of the arena. This study also examined the negative effects on health, including toxicity. Risks related to the environment, flammability and the physicochemical compatibility of methanol with materials were examined. The properties of the methanol/water solution were listed with reference to flash point, autoignition temperature, and the lower and upper flammable or explosive limits. tabs., figs. appendices.

Probing Reversible Chemistry in Coenzyme B12-Dependent Ethanolamine Ammonia Lyase with Kinetic Isotope Effects

Science.gov (United States)

Jones, Alex R; Rentergent, Julius; Scrutton, Nigel S; Hay, Sam

2015-01-01

Coenzyme B12-dependent enzymes such as ethanolamine ammonia lyase have remarkable catalytic power and some unique properties that enable detailed analysis of the reaction chemistry and associated dynamics. By selectively deuterating the substrate (ethanolamine) and/or the β-carbon of the 5′-deoxyadenosyl moiety of the intrinsic coenzyme B12, it was possible to experimentally probe both the forward and reverse hydrogen atom transfers between the 5′-deoxyadenosyl radical and substrate during single-turnover stopped-flow measurements. These data are interpreted within the context of a kinetic model where the 5′-deoxyadenosyl radical intermediate may be quasi-stable and rearrangement of the substrate radical is essentially irreversible. Global fitting of these data allows estimation of the intrinsic rate constants associated with CoC homolysis and initial H-abstraction steps. In contrast to previous stopped-flow studies, the apparent kinetic isotope effects are found to be relatively small. PMID:25950663

Net expansion of dried demineralized dentin matrix produced by monomer/alcohol saturation and solvent evaporation.

Science.gov (United States)

Agee, Kelli A; Becker, Thomas D; Joyce, Anthony P; Rueggeberg, Frederick A; Borke, James L; Waller, Jennifer L; Tay, Franklin R; Pashley, David H

2006-11-01

The purpose of this work was to determine if nonaqueous methacrylate monomer/alcohol mixtures could expand dried collapsed demineralized dentin matrix. Thin disks (ca. 200 microm) of human dentin were demineralized and placed in wells beneath contact probes of linear variable differential transformers. The probes were placed on water-saturated expanded matrices to record the shrinkage associated with drying. Monomer mixtures containing hydroxyethyl methacrylate, 2,2-bis[4-(2-hydroxy-3 methacryloyloxy)propoxyphenyl] propane, or triethyleneglycol dimethacrylate were mixed with methanol or ethanol at alcohol/monomer mass fraction % of 90/10, 70/30, 50/50, or 30/70. They were randomly applied to the dried matrices to determine the rate and magnitude of expansion; then shrinkage was recorded during evaporation of the alcohols. The results indicated that matrix expansion was positively correlated with the Hoy's solubility parameters for hydrogen bonding forces (delta(h)) of the monomer/solvent mixtures (p methanol-containing than with ethanol-containing monomer mixtures. For the test solutions, triethyleneglycol dimethacrylate-containing mixtures produced the slowest rate of matrix expansion and hydroxyethyl methacrylate-containing mixtures the most rapid expansion. When the solvents were evaporated, the matrix shrank in proportion to the solvent content and the delta(h) of the monomer-solvent mixtures. The results indicate that expansion of dried, collapsed dentin matrices requires that the delta(h) of the mixtures be larger than 17 (J/cm(3))(1/2). The greater the delta(h) of the monomer solutions, the greater the rate and extent of expansion.

Analysis of organic solvents and liquid mixtures using a fiber-tip evaporation sensor

Science.gov (United States)

Preter, Eyal; Donlagic, Denis; Artel, Vlada; Katims, Rachel A.; Sukenik, Chaim N.; Zadok, Avi

2014-05-01

The instantaneous size and rate of evaporation of pendant liquid droplets placed on the cleaved facet of a standard fiber are reconstructed based on reflected optical power. Using the evaporation dynamics, the relative contents of ethanol in ethanol-water binary mixtures are assessed with 1% precision and different blends of methanol in gasoline are properly recognized. The latter application, in particular, is significant for the use of alternative fuels in the automotive sector. Also, ten organic solvents are identified based on their evaporation from a fiber facet coated with a hydrophobic, selfassembled monolayer.

Temporal variation of VOC emission from solvent and water based wood stains

Science.gov (United States)

de Gennaro, Gianluigi; Loiotile, Annamaria Demarinis; Fracchiolla, Roberta; Palmisani, Jolanda; Saracino, Maria Rosaria; Tutino, Maria

2015-08-01

Solvent- and water-based wood stains were monitored using a small test emission chamber in order to characterize their emission profiles in terms of Total and individual VOCs. The study of concentration-time profiles of individual VOCs enabled to identify the compounds emitted at higher concentration for each type of stain, to examine their decay curve and finally to estimate the concentration in a reference room. The solvent-based wood stain was characterized by the highest Total VOCs emission level (5.7 mg/m3) that decreased over time more slowly than those related to water-based ones. The same finding was observed for the main detected compounds: Benzene, Toluene, Ethylbenzene, Xylenes, Styrene, alpha-Pinene and Camphene. On the other hand, the highest level of Limonene was emitted by a water-based wood stain. However, the concentration-time profile showed that water-based product was characterized by a remarkable reduction of the time of maximum and minimum emission: Limonene concentration reached the minimum concentration in about half the time compared to the solvent-based product. According to AgBB evaluation scheme, only one of the investigated water-based wood stains can be classified as a low-emitting product whose use may not determine any potential adverse effect on human health.

Identification of marine methanol-utilizing bacteria

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, M; Iwaki, H; Kouno, K; Inui, T

1980-01-01

A taxonomical study of 65 marine methanol-utilizing bacteria is described. They were Gram-negative, non-spore-forming rods with a polar flagellum and had marine bacterial properties and required vitamin B/sub 12/ for growth. All of them assimilated fructose in addition to C/sub 1/-compounds and produced acid oxidatively from fructose. Twenty-four strains assimilated only C/sub 1/-compounds. They were resistant to penicillin, oxytetracycline and 0/129 substance (Vibrio stat), and tolerant to 12% NaCl. Guanine-cytosine contents of deoxyribonucleic acid in typical strains fell in the range of 43.8 to 47.6%. Other morphological and physiological properties were almost the same as those of terrestrial methanol-utilizers. Bacteria in the first group (41 strains) were facultative methylotrophs and were divided into three subgroups by the assimilation of methylated amines, that is, subgroup I (30 strains) assimilated mono-, di- and tri-methylamine, subgroup II (9 strains) assimilated only mono-methylamine, the bacteria of subgroups I and II were named Alteromonas thalassomethanolica sp. nov. and subgroup III (2 strains) did not assimilate methylated amines, and was tentatively assigned as Alteromonas sp. The second group of bacteria (24 strains) was obligate methylotrophs, named Methylomonas thalassica sp. nov. and was divided into subgroup IV (15 strains) which assimilated mono-, di and tri-methylamine and subgroup V (9 strains) which assimilated mono-methylamine.

A New Process for Co-production of Ammonia and Methanol

International Nuclear Information System (INIS)

Soliman, A.

2004-01-01

A new process for co-production of ammonia and methanol is proposed. The process involves the production of synthesis gas by oxygen blown auto thermal reformer (ATR) at a pressure of 40-100 bars, a methanol synthesis loop at a pressure of 50-100 bars and an ammonia synthesis loop at a pressure of 200-300 bars. The oxygen required for the ATR is supplied by an air separation plant. The synthesis gases from the ATR are cooled and compressed, in a first stage compression, to the required methanol loop pressure. The purge stream from the methanol loop is sent to an intermediate temperature shift converter ITSC followed by a physical solvent CO 2 removal unit and them purified in a pressure Swing Adsorber (PSA). The purified hydrogen from the PSA together with the almost pure nitrogen from the air separation plant are re compressed, in a second stage compression

Validation of a UV Spectrometric Method for the Assay of Tolfenamic Acid in Organic Solvents

Directory of Open Access Journals (Sweden)

Sofia Ahmed

2015-01-01

Full Text Available The present study has been carried out to validate a UV spectrometric method for the assay of tolfenamic acid (TA in organic solvents. TA is insoluble in water; therefore, a total of thirteen commonly used organic solvents have been selected in which the drug is soluble. Fresh stock solutions of TA in each solvent in a concentration of 1 × 10−4 M (2.62 mg% were prepared for the assay. The method has been validated according to the guideline of International Conference on Harmonization and parameters like linearity, range, accuracy, precision, sensitivity, and robustness have been studied. Although the method was found to be efficient for the determination of TA in all solvents on the basis of statistical data 1-octanol, followed by ethanol and methanol, was found to be comparatively better than the other studied solvents. No change in the stock solution stability of TA has been observed in each solvent for 24 hours stored either at room (25±1°C or at refrigerated temperature (2–8°C. A shift in the absorption maxima has been observed for TA in various solvents indicating drug-solvent interactions. The studied method is simple, rapid, economical, accurate, and precise for the assay of TA in different organic solvents.

Brain uptake and metabolism of the endocannabinoid anandamide labeled in either the arachidonoyl or ethanolamine moiety

International Nuclear Information System (INIS)

Hu, Kun; Sonti, Shilpa; Glaser, Sherrye T.; Duclos, Richard I.; Gatley, Samuel J.

2017-01-01

Introduction: Anandamide (N-arachidonoylethanolamine) is a retrograde neuromodulator that activates cannabinoid receptors. The concentration of anandamide in the brain is controlled by fatty acid amide hydrolase (FAAH), which has been the focus of recent drug discovery efforts. Previous studies in C57BL/6 mice using [ 3 H-arachidonoyl]anandamide demonstrated deposition of tritium in thalamus and cortical areas that was blocked by treatment with an FAAH inhibitor and that was not seen in FAAH-knockout mice. This suggested that long chain fatty acid amides radiolabeled in the fatty acid moiety might be useful as ex vivo and in vivo radiotracers for FAAH, since labeled fatty acid released by hydrolysis would be rapidly incorporated into phospholipids with long metabolic turnover periods. Methods: Radiotracers were administered intravenously to conscious Swiss–Webster mice, and radioactivity concentrations in brain areas was quantified and radiolabeled metabolites determined by radiochromatography. Results: [ 14 C]Arachidonic acid, [ 14 C-arachidonoyl]anandamide and [ 14 C-ethanolamine]anandamide, and also [ 14 C]myristic acid, [ 14 C-myristoyl]myristoylethanolamine and [ 14 C-ethanolamine]myristoyl-ethanolamine all had very similar distribution patterns, with whole brain radioactivity concentrations of 2–4% injected dose per gram. Pretreatment with the potent selective FAAH inhibitor URB597 did not significantly alter distribution patterns although radiochromatography demonstrated that the rate of incorporation of label from [ 14 C]anandamide into phospholipids was decreased. Pretreatment with the muscarinic agonist arecoline which increases cerebral perfusion increased brain uptake of radiolabel from [ 14 C]arachidonic acid and [ 14 C-ethanolamine]anandamide, and (in dual isotope studies) from the unrelated tracer [ 125 I]RTI-55. Conclusions: Together with our previously published study with [ 18 F-palmitoyl]16-fluoro-palmitoylethanolamine, the data show that the

Anti-inflammatory and analgesic activities of solvent fractions of the leaves of Moringa stenopetala Bak. (Moringaceae) in mice models.

Science.gov (United States)

Tamrat, Yohannes; Nedi, Teshome; Assefa, Solomon; Teklehaymanot, Tilahun; Shibeshi, Workineh

2017-09-29

Many people still experience pain and inflammation regardless of the available drugs for treatments. In addition, the available drugs have many side effects, which necessitated a quest for new drugs from several sources in which medicinal plants are the major one. This study evaluated the analgesic and anti- inflammatory activity of the solvent fractions of Moringa stenopetala in rodent models of pain and inflammation. Successive soxhlet and maceration were used as methods of extractions using solvents of increasing polarity; chloroform, methanol and water. Swiss albino mice models were used in radiant tail flick latency, acetic acid induced writhing and carrageenan induced paw edema to assess the analgesic and anti-inflammatory activities. The test groups received different doses (100 mg/kg, 200 mg/kg and 400 mg/kg) of the three fractions (chloroform, methanol and aqueous). The positive control groups received morphine (20 mg/kg) or aspirin (100 mg/kg or 150 mg/kg) based on the respective models. The negative control groups received the 10 ml/kg of vehicles (distilled water or 2% Tween 80). In all models, the chloroform fraction had protections only at a dose of 400 mg/kg. However, the methanol and aqueous fraction at all doses have shown significant central and peripheral analgesic activities with a comparable result to the standards. The aqueous and methanol fractions significantly reduced carrageenan induced inflammation in a dose dependent manner, in which the highest reduction of inflammation was observed in aqueous fraction at 400 mg/kg. This study provided evidence on the traditionally claimed uses of the plant in pain and inflammatory diseases, and Moringa stenopetala could be potential source for development of new analgesic and anti-inflammatory drugs.

Population dynamics of toxic phytoplankton and bacterial flora in the waters of the low Adriatic sea; Dinamica di popolazione di fitoplancton tossico e flora batterica nel basso Adriatico

Energy Technology Data Exchange (ETDEWEB)

Caroppo, C.; Stabili, L.; Cavallo, R.A.; Pastore, M. [CNR, Ist. Sperimentale Talassografico Attlio Cerruti, Taranto (Italy); Marchiori, E. [Rome Univ., Rome (Italy). Dipt. di Chimica Organica; Bruno, M. [Istituto Superiore di Sanita' , Laboratorio di Igiene Ambientale, Rome (Italy)

2000-07-01

The coastal areas of the Southern Adriatic Sea, in particular the Apulian ones, may be considered an example of intact ecosystem and represent an ideal term of comparison to other marine ecosystems having higher levels of pollution (Northern Adriatic Sea). In order to evaluate the sanitary levels of this environment, four transect were investigated during two years monitoring (April 1995-March 1997) along the Otranto Channel coasts, by joint research groups of the Environmental Hygiene Laboratory of the Istituto Superiore di Sanita' and the Istituto Sperimentale Talassografico A. Cerruti of CNR in Taranto. The study underlines the phytoplanktic and bacterial population dynamics, and the detection of the microbiological water quality along the coast tract Brindisi-Lecce-Otranto-S. Maria di Leuca. The results acquired pointed out population dynamics of some potantially toxic species of Dinophysis genus and Pseudo-nitzschia delicatissima. These depended on the winter nutrient loads due to the ASW (Adriatic Superficial Waters) and to the LIW (Levantine Intermediate Waters). The bacterial community was mainly constituted by genera Aeromonas, Photobacterium, Cytophaga and Pseudomonas. Also the presence of Enterobacteriaceae family was relevant. Among the pathogenic vibrios the most frequently isolated species were Vibrio alginolyticus and Vibrio vulnificus. [Italian] Considerando che le zone del basso Adriatico, in particolare quelle pugliesi, costituiscono un biotopo ancora relativamente inalterato, esse sono state oggetto di un'indagine sperimentale condotta in 24 mesi di attivita' (aprile 1995-marzo 1997) lungo le coste del Canale di Otranto, ad opera di un gruppo congiunto del Laboratorio di Igiene Ambientale dell'Istituto Superiore di Sanita' e dei laboratori dell'Istituto Sperimentale Talassografico A. Cerruti del CNR di Taranto, ai fini di valutare lo stato di salute di questo ambiente, che fornisce, con buona probabilita', un

Exfoliating and Dispersing Few-Layered Graphene in Low-Boiling-Point Organic Solvents towards Solution-Processed Optoelectronic Device Applications.

Science.gov (United States)

Zhang, Lu; Miao, Zhongshuo; Hao, Zhen; Liu, Jun

2016-05-06

With normal organic surfactants, graphene can only be dispersed in water and cannot be dispersed in low-boiling-point organic solvents, which hampers its application in solution-processed organic optoelectronic devices. Herein, we report the exfoliation of graphite into graphene in low-boiling-point organic solvents, for example, methanol and acetone, by using edge-carboxylated graphene quantum dots (ECGQD) as the surfactant. The great capability of ECGQD for graphene dispersion is due to its ultralarge π-conjugated unit that allows tight adhesion on the graphene surface through strong π-π interactions, its edge-carboxylated structure that diminishes the steric effects of the oxygen-containing functional groups on the basal plane of ECGQD, and its abundance of carboxylic acid groups for solubility. The graphene dispersion in methanol enables the application of graphene:ECGQD as a cathode interlayer in polymer solar cells (PSCs). Moreover, the PSC device performance of graphene:ECGQD is better than that of Ca, the state-of-the-art cathode interlayer material. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mirror-symmetry-breaking in poly[(9,9-di-n-octylfluorenyl- 2,7-diyl)-alt-biphenyl] (PF8P2) is susceptible to terpene chirality, achiral solvents, and mechanical stirring.

Science.gov (United States)

Fujiki, Michiya; Kawagoe, Yoshifumi; Nakano, Yoko; Nakao, Ayako

2013-06-17

Solvent chirality transfer of (S)-/(R)-limonenes allows the instant generation of optically active PF8P2 aggregates with distinct circular dichroism (CD)/circularly polarized luminescence (CPL) amplitudes with a high quantum yield of 16-20%. The present paper also reports subtle mirror-symmetry-breaking effects in CD-/CPL-amplitude and sign, CD/UV-vis spectral wavelengths, and photodynamics of the aggregates, though the reasons for the anomaly are unsolved. However, these photophysical properties depend on (i) the chemical natures of chiral and achiral molecules when used in solvent quantity, (ii) clockwise and counterclockwise stirring operations, and (iii) the order of addition of limonene and methanol to the chloroform solution.

Carbon nanotubes based methanol sensor for fuel cells application.

Science.gov (United States)

Kim, D W; Lee, J S; Lee, G S; Overzet, L; Kozlov, M; Aliev, A E; Park, Y W; Yang, D J

2006-11-01

An electrochemical sensor is built using vertically grown multi-walled carbon nanotubes (MWNTs) micro-array to detect methanol concentration in water. This study is done for the potential use of the array as methanol sensor for portable units of direct methanol fuel cells (DMFCs). Platinum (Pt) nanoparticles electro-deposited CNTs (Pt/CNTs) electrode shows high sensitivity in the measurement of methanol concentration in water with cyclic voltammetry (CV) measurement at room temperature. Further investigation has also been undertaken to measure the concentration by changing the amount of the mixture of methanol and formic acid in water. We compared the performance of our micro array sensor built with Pt/CNTs electrodes versus that of Pt wire electrode using CV measurement. We found that our Pt/CNTs array sensor shows high sensitivity and detects methanol concentrations in the range of 0.04 M to 0.10 M. In addition, we found that co-use of formic acid as electrolyte enables us to measure up to 1.0 M methanol concentration.

Is Water a Universal Solvent for Life?

Science.gov (United States)

Pohorill, Andrew

2012-01-01

There are strong reasons to believe that the laws, principles and constraints of physics and chemistry are universal. It is much less clear how this universality translates into our understanding of the origins of life. Conventionally, discussions of this topic focus on chemistry that must be sufficiently rich to seed life. Although this is clearly a prerequisite for the emergence of living systems, I propose to focus instead on self-organization of matter into functional structures capable of reproduction, evolution and responding to environmental changes. In biology, most essential functions are largely mediated by noncovalent interactions (interactions that do not involve making or breaking chemical bonds). Forming chemical bonds is only a small part of what living systems do. There are specific implications of this point of view for universality. I will concentrate on one of these implications. Strength of non-covalent interactions must be properly tuned. If they were too weak, the system would exhibit undesired, uncontrolled response to natural fluctuations of physical and chemical parameters. If they were too strong kinetics of biological processes would be slow and energetics costly. This balance, however, is not a natural property of complex chemical systems. Instead, it has to be achieved with the aid of an appropriate solvent for life. In particular, potential solvents for life must be characterized by a high dielectric constant to ensure solubility of polar species and sufficient flexibility of biological structures stabilized by electrostatic interactions. Among these solvents, water exhibits a remarkable trait that it also promotes solvophobic (hydrophobic) interactions between non-polar species, typically manifested by a tendency of these species to aggregate and minimize their contacts with the aqueous solvent. Hydrophobic interactions are responsible, at least in part, for many self-organization phenomena in biological systems, such as the formation

Magnetic, catalytic, EPR and electrochemical studies on binuclear ...

Indian Academy of Sciences (India)

Magnetic, catalytic, EPR and electrochemical studies on binuclear copper(II) complexes ... to the oxidation of 3,5-di--butylcatechol to the corresponding quinone. ... EPR spectral studies in methanol solvent show welldefined four hyperfine ...

Staining of proteins in gels with Coomassie G-250 without organic solvent and acetic acid.

Science.gov (United States)

Lawrence, Ann-Marie; Besir, H Uuml Seyin

2009-08-14

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents (Methanol, Ethanol or 2-Propanol) and acetic acid are used for fixation, staining and destaining of proteins in a gel after SDS-PAGE. To speed up the procedure, heating the staining solution in the microwave oven for a short time is frequently used. This usually results in evaporation of toxic or hazardous Methanol, Ethanol or 2-Propanol and a strong smell of acetic acid in the lab which should be avoided due to safety considerations. In a protocol originally published in two patent applications by E.M. Wondrak (US2001046709 (A1), US6319720 (B1)), an alternative composition of the staining solution is described in which no organic solvent or acid is used. The CBB is dissolved in bidistilled water (60-80 mg of CBB G-250 per liter) and 35 mM HCl is added as the only other compound in the staining solution. The CBB staining of the gel is done after SDS-PAGE and thorough washing of the gel in bidistilled water. By heating the gel during the washing and staining steps, the process can be finished faster and no toxic or hazardous compounds are evaporating. The staining of proteins occurs already within 1 minute after heating the gel in staining solution and is fully developed after 15-30 min with a slightly blue background that is destained completely by prolonged washing of the stained gel in bidistilled water, without affecting the stained protein bands.

studies on solvent extraction of free hydrogen cyanide from river water

African Journals Online (AJOL)

A method for free and strongly complexed cyanide measurement in river water was developed. Recovery tests from solution with and without river water, using various solvent combinations and background control were investigated to obtain an accurate and precise extraction method for the measurement of hydrogen ...

Performance of the SMD and SM8 models for predicting solvation free energy of neutral solutes in methanol, dimethyl sulfoxide and acetonitrile

Science.gov (United States)

Zanith, Caroline C.; Pliego, Josefredo R.

2015-03-01

The continuum solvation models SMD and SM8 were developed using 2,346 solvation free energy values for 318 neutral molecules in 91 solvents as reference. However, no solvation data of neutral solutes in methanol was used in the parametrization, while only few solvation free energy values of solutes in dimethyl sulfoxide and acetonitrile were used. In this report, we have tested the performance of the models for these important solvents. Taking data from literature, we have generated solvation free energy, enthalpy and entropy values for 37 solutes in methanol, 21 solutes in dimethyl sulfoxide and 19 solutes in acetonitrile. Both SMD and SM8 models have presented a good performance in methanol and acetonitrile, with mean unsigned error equal or less than 0.66 and 0.55 kcal mol-1 in methanol and acetonitrile, respectively. However, the correlation is worse in dimethyl sulfoxide, where the SMD and SM8 methods present mean unsigned error of 1.02 and 0.95 kcal mol-1, respectively. Our results point out the SMx family of models need be improved for dimethyl sulfoxide solvent.

Distribution of MEG and methanol in well-defined hydrocarbon and water systems: Experimental measurement and modeling using the CPA EoS

DEFF Research Database (Denmark)

Riaz, Muhammad; Yussuf, Mustafe A.; Kontogeorgis, Georgios

2013-01-01

+ water. These data are satisfactorily correlated (binaries) and predicted (ternaries) using Cubic Plus Association (CPA) equation of state (EoS). CPA is also applied to binary LLE of aromatic hydrocarbon + water and VLE of methane + methanol. Finally the distribution of water and inhibitors (methanol...... and MEG) in various phases is modeled using CPA. The hydrocarbon phase consists of mixture-1 (methane, ethane, n-butane) or mixture-2 (methane, ethane, propane, n-butane, n-heptane, toluene and n-decane). CPA can satisfactorily predict the water content in the gas phase of the multicomponent systems...

New Polymeric Membranes for Organic Solvent Nanofiltration

KAUST Repository

Aburabie, Jamaliah

2017-05-01

membranes. Composite membranes were prepared using PAN and crosslinked PAN supports; these membranes were tested for methanol and DMF. Freestanding nanofilms fixed on alumina were also tested for methanol and DMF as well as many other harsh solvents. The alginate composite membranes showed excellent solvent stability and good permeances and a MWCO of around 1300 g/mol.

Variation of energy absorption buildup factors with incident photon energy and penetration depth for some commonly used solvents

International Nuclear Information System (INIS)

Singh, Parjit S.; Singh, Tejbir; Kaur, Paramjeet

2008-01-01

G.P. fitting method has been used to compute energy absorption buildup factor of some commonly used solvents such as acetonitrile (C 4 H 3 N), butanol (C 4 H 9 OH), chlorobenzene (C 6 H 5 Cl), diethyl ether (C 4 H 10 O), ethanol (C 2 H 5 OH), methanol (CH 3 OH), propanol (C 3 H 7 OH) and water (H 2 O) for the wide energy range (0.015-15.0 MeV) up to the penetration depth of 10 mean free path. The variation of energy absorption buildup factor with chemical composition as well as incident photon energy for the selected solvents has been studied. It has been observed that the maximum value of energy absorption buildup factors shifts to the slightly higher incident photon energy with the increase in equivalent atomic number of the solvent and the solvent with least equivalent atomic number possesses the maximum value of energy absorption buildup factor

Photostability of 6-MAM and morphine exposed to controlled UV irradiation in water and methanol solution: HRMS for the characterization of transformation products and comparison with the dry state.

Science.gov (United States)

Miolo, Giorgia; Tucci, Marianna; Mazzoli, Alessandra; Ferrara, Santo Davide; Favretto, Donata

2016-07-15

The UVA and UVB light-induced behaviour of 6-monoacetylmorphine (6-MAM) and morphine, the main metabolites of heroin, was studied in methanol, aqueous solution and in the dry state. UVA and UVB irradiations were performed for different times (radiant energies of 20-300J/cm(2)). UV spectra of irradiated samples were compared with samples kept in the dark. To estimate the extent of photolysis, positive ion electrospray ionization experiments were performed on the irradiated samples by LC-HRMS. Tentative identification of photoproducts was performed on the basis of their elemental formula as calculated by HRMS results. Morphine and 6-MAM demonstrated to be quite stable under UVA light but very sensitive to UVB irradiation. In methanol solutions they undergo a similar pattern, both reaching 90% photodegradation after 100J/cm(2) of UVB, with a slightly faster kinetic for morphine at lower doses. In water, the yields of photodegradation are nearly one third lower than in methanol. In the solid state, the yield of photodegradation is lower than in solution. The structures of some UVB-induced degradation products are proposed. Photoaddition of the solvent and photooxidation seem the main pathways of phototransformation of these molecules. Moreover, both compounds revealed to generate singlet oxygen under UVB exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Study on fuel supplying method and methanol concentration sensor for the high efficient operation of methanol fuel cells. Methanol nenryo denchi no unten ni okeru nenryo kyokyu hoho no kento to methanol nodo sensor no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Tsukui, Tsutomu; Doi, Ryota; Yasukawa, Saburo; Kuroda, Osamu [Hirachi, Ltd., Tokyo, (Japan)

1990-01-20

A fuel supplying method was studied and demonstrated, essential to the high efficient operation of methanol fuel cells. Methanol and water were supplied independently from each tank to an anordic electrolyte tank in a circulating system, detecting a methanol concentration and liquid level of anordic electrolyte by each sensor, respectively. A methanol sensor was also developed to detect accurately the concentration based on electrochemical reaction under a constant voltage. A detection control circuit was insulated from a constant-voltage power supply to prevent external noises. The methanol sensor output was compensated for temperature, and a new level sensing method was adopted to send out a command comparing different responses to electrolyte shortage. As the methanol fuel cell was operated with this fuel supplying system, the stable characteristics of the cell were obtained within the variation of {plus minus} 0.1mol/l from the specified methanol concentration. 6 refs., 17 figs., 1 tab.

Luminescence study on solvation of americium(III), curium(III) and several lanthanide(III) ions in nonaqueous and binary mixed solvents

International Nuclear Information System (INIS)

Kimura, T.; Nagaishi, R.; Kato, Y.; Yoshida, Z.

2001-01-01

The luminescence lifetimes of An(III) and Ln(III) ions [An=Am and Cm; Ln=Nd, Sm, Eu, Tb and Dy] were measured in dimethyl sulfoxide(DMSO), N,N-dimethylformamide(DMF), methanol(MeOH), water and their perdeuterated solvents. Nonradiative decay rates of the ions were in the order of H 2 O > MeOH > DMF > DMSO, indicating that O-H vibration is more effective quencher than C-H, C=O, and S=O vibrations in the solvent molecules. Maximal lifetime ratios τ D /τ H were observed for Eu(III) in H 2 O, for Sm(III) in MeOH and DMF, and for Sm(III) and Dy(III) in DMSO. The solvent composition in the first coordination sphere of Cm(III) and Ln(III) in binary mixed solvents was also studied by measuring the luminescence lifetime. Cm(III) and Ln(III) were preferentially solvated by DMSO in DMSO-H 2 O, by DMF in DMF-H 2 O, and by H 2 O in MeOH-H 2 O over the whole range of the solvent composition. The order of the preferential solvation, i.e., DMSO > DMF > H 2 O > MeOH, correlates with the relative basicity of these solvents. The Gibbs free energy of transfer of ions from water to nonaqueous solvents was further estimated from the degree of the preferential solvation. (orig.)

A new approach to solvent extraction: Electronic pulses shatter water droplets

International Nuclear Information System (INIS)

Anon.

1991-01-01

Researchers in the Chemical Technology Division of Oak Ridge National Laboratory (ORNL) have invented a device that represents a significant improvement in the area of solvent extraction, which is a widely used technique to recover valuable materials from a liquid stream. Known as the Emulsion Phase Contactor (EPC), the technology uses a pulsed electrical field to enhance recovery of chemicals (either valuable products or pollutants) that are dissolved in water. Because of its higher efficiency, the recovery method can be accomplished in much smaller vessels than those used in conventional solvent extractors, which use mechanical processes to recover chemicals. When water droplets carrying the substance to be extracted are introduced into the EPC, they are shattered by electronic pulses that produce water particles in the 1- to 5-micron size range. These water particles are up to 100 times smaller than those created by mechanical agitation. These tiny particles produce a much greater surface area than can be achieved using chemical agitators, enabling the chemical solvent to extract more material from the water base. In addition, the EPC uses much less power than mechanical methods and has no moving parts; therefore, servicing requirements for the extraction apparatus are expected to be significantly reduced. ORNL researchers initially tested the technology at a very small scale, and evaluated its capabilities in extracting high-value substances such as isotopes, pharmaceuticals, and precious metals. Further work has indicated that the EPC can be applied on a much larger scale to handle more common chemical substances

Application of acetone acetals as water scavengers and derivatization agents prior to the gas chromatographic analysis of polar residual solvents in aqueous samples.

Science.gov (United States)

van Boxtel, Niels; Wolfs, Kris; Van Schepdael, Ann; Adams, Erwin

2015-12-18

The sensitivity of gas chromatography (GC) combined with the full evaporation technique (FET) for the analysis of aqueous samples is limited due to the maximum tolerable sample volume in a headspace vial. Using an acetone acetal as water scavenger prior to FET-GC analysis proved to be a useful and versatile tool for the analysis of high boiling analytes in aqueous samples. 2,2-Dimethoxypropane (DMP) was used in this case resulting in methanol and acetone as reaction products with water. These solvents are relatively volatile and were easily removed by evaporation enabling sample enrichment leading to 10-fold improvement in sensitivity compared to the standard 10μL FET sample volumes for a selection of typical high boiling polar residual solvents in water. This could be improved even further if more sample is used. The method was applied for the determination of residual NMP in an aqueous solution of a cefotaxime analogue and proved to be considerably better than conventional static headspace (sHS) and the standard FET approach. The methodology was also applied to determine trace amounts of ethylene glycol (EG) in aqueous samples like contact lens fluids, where scavenging of the water would avoid laborious extraction prior to derivatization. During this experiment it was revealed that DMP reacts quantitatively with EG to form 2,2-dimethyl-1,3-dioxolane (2,2-DD) under the proposed reaction conditions. The relatively high volatility (bp 93°C) of 2,2-DD makes it possible to perform analysis of EG using the sHS methodology making additional derivatization reactions superfluous. Copyright © 2015 Elsevier B.V. All rights reserved.

Preliminary phytochemicals evaluation of different solvent extracts of Gynura procumbens

International Nuclear Information System (INIS)

Hazlina Ahmad Hassali; Fazliana Mohd Saaya; Anuar, A.M.K.; Shafii Khamis

2014-01-01

Phytochemicals are natural bioactive compounds found in plants, such as vegetables, fruits, medicinal plants, flowers, leaves and roots that work with nutrients and fibers to protect against various human diseases. Gynura procumbens or locally known as Sambung Nyawa is a plant species widely planted in many warmer regions. It is a perennial plant of the Asteraceae family, which may grow to 100 cm high with oval-shaped, leaves to 10 cm long and have a rather fleshy feel. Gynura procumbens has been used for the treatment of eruptive fevers, rash and kidney disease. The leaves of this plant continue to be used as folk medicine to control diabetes mellitus and hyperlipidaemia. The aim of this research was to evaluate the presence of phytochemicals constituents in different solvent extracts of Gynura procumbens leaves. Qualitative phytochemicals screening of hexane, chloroform, methanol and water extracts were carried out for the detection of terpenoids, alkaloids, flavonoids, tannins, saponins, steroids, lipids, coumarin, cardiac glycosides and anthraquinones. The phytochemicals screening showed positive results for terpenoids, alkaloids, flavonoids, tannins, saponins, lipids, coumarin and anthraquinones in methanol and water extracts of Gynura procumbens. The diversity of phytochemicals present suggests that Gynura procumbens leaves could serve as a source of useful drugs. (author)

Steps on rutile TiO2(110): Active sites for water and methanol dissociation

DEFF Research Database (Denmark)

Martinez, Umberto; Vilhelmsen, Lasse; Kristoffersen, Henrik Høgh

2011-01-01

for each step edge, more stable, reconstructed structures were found for the step edge, while the bulk truncated structures were recovered for the step edge.We demonstrate how oxygen vacancies along these defects have lower formation energies than on flat terraces and how water and methanol...

Photocatalytic conversion of methane to methanol

Energy Technology Data Exchange (ETDEWEB)

Taylor, C.E.; Noceti, R.P.; D`Este, J.R. [Pittsburgh Energy Technology Center, PA (United States)

1995-12-31

A long-term goal of our research group is the exploration of novel pathways for the direct oxidation of methane to liquid fuels, chemicals, and intermediates. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol is attractive. The products of reaction, methanol and hydrogen, are both commercially desirable, methanol being used as is or converted to a variety of other chemicals, and the hydrogen could be utilized in petroleum and/or chemical manufacturing. Methane is produced as a by-product of coal gasification. Depending upon reactor design and operating conditions, up to 18% of total gasifier product may be methane. In addition, there are vast proven reserves of geologic methane in the world. Unfortunately, a large fraction of these reserves are in regions where there is little local demand for methane and it is not economically feasible to transport it to a market. There is a global research effort under way in academia, industry, and government to find methods to convert methane to useful, more readily transportable and storable materials. Methanol, the initial product of methane oxidation, is a desirable product of conversion because it retains much of the original energy of the methane while satisfying transportation and storage requirements. Investigation of direct conversion of methane to transportation fuels has been an ongoing effort at PETC for over 10 years. One of the current areas of research is the conversion of methane to methanol, under mild conditions, using light, water, and a semiconductor photocatalyst. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol, is attractive. Research in the laboratory is directed toward applying the techniques developed for the photocatalytic splitting of the water and the photochemical conversion of methane.

The workings of a molecular thermometer: the vibrational excitation of carbon tetrachloride by a solvent.

Science.gov (United States)

Graham, Polly B; Matus, Kira J M; Stratt, Richard M

2004-09-15

An intriguing energy-transfer experiment was recently carried out in methanol/carbon tetrachloride solutions. It turned out to be possible to watch vibrational energy accumulating in three of carbon tetrachloride's modes following initial excitation of O-H and C-H stretches in methanol, in effect making those CCl(4) modes "molecular thermometers" reporting on methanol's relaxation. In this paper, we use the example of a CCl(4) molecule dissolved in liquid argon to examine, on a microscopic level, just how this kind of thermal activation occurs in liquid solutions. The fact that even the lowest CCl(4) mode has a relatively high frequency compared to the intermolecular vibrational band of the solvent means that the only solute-solvent dynamics relevant to the vibrational energy transfer will be extraordinarily local, so much so that it is only the force between the instantaneously most prominent Cl and solvent atoms that will significantly contribute to the vibrational friction. We use this observation, within the context of a classical instantaneous-pair Landau-Teller calculation, to show that energy flows into CCl(4) primarily via one component of the nominally degenerate, lowest frequency, E mode and does so fast enough to make CCl(4) an excellent choice for monitoring methanol relaxation. Remarkably, within this theory, the different symmetries and appearances of the different CCl(4) modes have little bearing on how well they take up energy from their surroundings--it is only how high their vibrational frequencies are relative to the solvent intermolecular vibrational band edge that substantially favors one mode over another.

The effect of re-dissolution solvents and HPLC columns on the analysis of mycosporine-like amino acids in the eulittoral macroalgae Prasiola crispa and Porphyra umbilicalis

Science.gov (United States)

Karsten, Ulf; Escoubeyrou, Karine; Charles, François

2009-09-01

Many macroalgal species that are regularly exposed to high solar radiation such as the eulittoral green alga Prasiola crispa and the red alga Porphyra umbilicalis synthesize and accumulate high concentrations of mycosporine-like amino acids (MAAs) as UV-sunscreen compounds. These substances are typically extracted with a widely used standard protocol following quantification by various high performance liquid chromatography (HPLC) techniques. However, further preparation steps prior to HPLC analysis as well as different HPLC column types have not been systematically checked regarding separation quality and reproducibility. Therefore pure methanol, distilled water and HPLC eluent were evaluated as re-dissolution solvent for dried Prasiola and Porphyra extracts, which were subsequently analyzed on three reversed-phase C8 and C18 HPLC columns. The data indicate that distilled water and the HPLC eluent gave almost identical peak patterns and MAA contents on the C8 and C18 columns. In contrast, the application of the widely used methanol led to double peaks or even the loss of specific peaks as well as to a strong decline in total MAA amounts ranging from about 35% of the maximum in P. crispa to 80% of the maximum in P. umbilicalis. Consequently, methanol should be avoided as re-dissolution solvent for the HPLC sample preparation. An improved protocol for the MAA analysis in macroalgae in combination with a reliable C18 column is suggested.

Effect of methanol, n-hexane and aqueous extract of Irvingia ...

African Journals Online (AJOL)

Bush mango leaf (Irvingia gabonensis) is commonly used locally to treat diarrhoea. The present study evaluated the anti-diarrhoea effect of this plant extract on albino rats induced with castor oil. Fresh tender leaf of this plant was collected, air-dried, powdered and percolated in n-hexane, methanol and aqueous solvents.

Cascade catalysis in membranes with enzyme immobilization for multienzymatic conversion of CO2 to methanol

DEFF Research Database (Denmark)

Luo, Jianquan; Meyer, Anne S.; Mateiu, Ramona Valentina

2015-01-01

.e. by directing membrane fouling formation), without any addition of organic solvent. Such coimmobilization and sequential immobilization systems were examined for the production of methanol from CO2 with formate dehydrogenase (FDH), formaldehyde dehydrogenase (FaldDH) and alcohol dehydrogenase (ADH). Enzyme...... for multi-enzymatic cascade systems, but also reveals the reaction bottleneck and provides possible solutions for the bioconversion of CO2 to methanol....

Reduction of Solvent Effect in Reverse Phase Gradient Elution LC-ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Sullivan, Patrick Allen [Iowa State Univ., Ames, IA (United States)

2005-12-17

Quantification in liquid chromatography (LC) is becoming very important as more researchers are using LC, not as an analytical tool itself, but as a sample introduction system for other analytical instruments. The ability of LC instrumentation to quickly separate a wide variety of compounds makes it ideal for analysis of complex mixtures. For elemental speciation, LC is joined with inductively coupled plasma mass spectrometry (ICP-MS) to separate and detect metal-containing, organic compounds in complex mixtures, such as biological samples. Often, the solvent gradients required to perform complex separations will cause matrix effects within the plasma. This limits the sensitivity of the ICP-MS and the quantification methods available for use in such analyses. Traditionally, isotope dilution has been the method of choice for LC-ICP-MS quantification. The use of naturally abundant isotopes of a single element in quantification corrects for most of the effects that LC solvent gradients produce within the plasma. However, not all elements of interest in speciation studies have multiple naturally occurring isotopes; and polyatomic interferences for a given isotope can develop within the plasma, depending on the solvent matrix. This is the case for reverse phase LC separations, where increasing amounts of organic solvent are required. For such separations, an alternative to isotope dilution for quantification would be is needed. To this end, a new method was developed using the Apex-Q desolvation system (ESI, Omaha, NE) to couple LC instrumentation with an ICP-MS device. The desolvation power of the system allowed greater concentrations of methanol to be introduced to the plasma prior to destabilization than with direct methanol injection into the plasma. Studies were performed, using simulated and actual linear methanol gradients, to find analyte-internal standard (AIS) pairs whose ratio remains consistent (deviations {+-} 10%) over methanol concentration ranges of 5

Adaptation of the autotrophic acetogen Sporomusa ovata to methanol accelerates the conversion of CO2 to organic products

DEFF Research Database (Denmark)

Tremblay, Pier-Luc; Höglund, Daniel; Koza, Anna

2015-01-01

, and biochemical studies revealed that the molecular mechanisms responsible for the novel characteristics of the adapted strain were associated with the methanol oxidation pathway and the Wood-Ljungdahl pathway of acetogens along with biosynthetic pathways, cell wall components, and protein chaperones. The results...... to grow quicker autotrophically with methanol, a toxic C1 compound, as the sole substrate. Better growth on different concentrations of methanol and with H2-CO2 indicated the adapted strain had a more efficient autotrophic metabolism and a higher tolerance to solvent. The growth rate on methanol...

Oxidation of hazardous waste in supercritical water: A comparison of modeling and experimental results for methanol destruction

International Nuclear Information System (INIS)

Butler, P.B.; Bergan, N.E.; Bramlette, T.T.; Pitz, W.J.; Westbrook, C.K.

1991-01-01

Recent experiments at Sandia National Laboratories conducted in conjunction with MODEC Corporation have demonstrated successful clean- up of contaminated water in a supercritical water reactor. These experiments targeted wastes of interest to Department of Energy production facilities. In this paper we present modeling and experimental results for a surrogate waste containing 98% water, 2% methanol, and parts per million of chlorinated hydrocarbons and laser dyes. Our initial modeling results consider only methanol and water. Experimental data are available for inlet and outlet conditions and axial temperature profiles along the outside reactor wall. The purpose of our model is to study the chemical and physical processes inside the reactor. We are particularly interested in the parameters that control the location of the reaction zone. The laboratory-scale reactor operates at 25 MPa., between 300 K and 900 K; it is modeled as a plug-flow reactor with a specified temperature profile. We use Chemkin Real-Gas to calculate mixture density, with the Peng-Robinson equation of state. The elementary reaction set for methanol oxidation and reactions of other C 1 and C 2 hydrocarbons is based on previous models for gas-phase kinetics. Results from our calculations show that the methanol is 99.9% destroyed at 1/3 the total reactor length. Although we were not able to measure composition of the fluid inside the experimental reactor, this prediction occurs near the location of the highest reactor temperature. This indicates that the chemical reaction is triggered by thermal effects, not kinetic rates. Results from ideal-gas calculations show nearly identical chemical profiles inside the reactor in dimensionless distance. However, reactor residence times are overpredicted by nearly 150% using an ideal-gas assumption. Our results indicate that this oxidation process can be successfully modeled using gas-phase chemical mechanisms. 23 refs., 8 figs

Effect of solvents and oil content on direct transesterification of wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized lipase as the biocatalyst.

Science.gov (United States)

Tran, Dang-Thuan; Chen, Ching-Lung; Chang, Jo-Shu

2013-05-01

In this work, a one-step extraction/transesterification process was developed to directly convert wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 into biodiesel using immobilized Burkholderia lipase as the catalyst. The microalgal biomass (water content of 86-91%; oil content 14-63%) was pre-treated by sonication to disrupt the cell walls and then directly mixed with methanol and solvent to carry out the enzymatic transesterification. Addition of a sufficient amount of solvent (hexane is most preferable) is required for the direct transesterification of wet microalgal biomass, as a hexane-to-methanol mass ratio of 1.65 was found optimal for the biodiesel conversion. The amount of methanol and hexane required for the direct transesterification process was also found to correlate with the lipid content of the microalga. The biodiesel synthesis process was more efficient and economic when the lipid content of the microalgal biomass was higher. Therefore, using high-lipid-content microalgae as feedstock appears to be desirable. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

extractive distillation. In extractive distillation the solvent affects the relative volatility of the two key compounds to be separated. In other words, for a two column distillation sequence configuration, the lighter boiling compound is obtained as the top product of the first distillation column...... of the better replacements for methyl tert-butyl ether. Methanol (MeOH) is used as a common raw material in the production of DMC, for example, using phosgene with hydrochloric acid as the by-product, using carbon monoxide and oxygen with water as the by-product, using a cyclic carbonate with a glycol as the by...... the best separation system, with the focus on solvent generation, screening and verification for extractive distillation for the separation of MeOH and DMC. The three stage approach will be presented and it will be shown that existing solvent candidates found in the literature are already generated...

PHYTOCHEMICALS ANALYSIS AND TLC FINGERPRINTING OF METHANOLIC EXTRACTS OF THREE MEDICINAL PLANTS

OpenAIRE

Dutta Jayashree

2013-01-01

The present work is done on three medicinal plants (Enhydra fluctuans, Lecuas aspera and Dillinia indica) in order to investigate the presence of the various types of Phytoconstituents. The leaves of all three plants were extracted using methanol as solvents. For the purpose of phytochemical investigation, Preliminary qualitative chemical test and TLC were mainly used. Thin layer chromatography (TLC) has been carried out on all the three plants in two different solvent systems, which showed d...

Mirror-Symmetry-Breaking in Poly[(9,9-di-n-octylfluorenyl-2,7-diyl-alt-biphenyl] (PF8P2 is Susceptible to Terpene Chirality, Achiral Solvents, and Mechanical Stirring

Directory of Open Access Journals (Sweden)

Ayako Nakao

2013-06-01

Full Text Available Solvent chirality transfer of (S-/(R-limonenes allows the instant generation of optically active PF8P2 aggregates with distinct circular dichroism (CD/circularly polarized luminescence (CPL amplitudes with a high quantum yield of 16–20%. The present paper also reports subtle mirror-symmetry-breaking effects in CD-/CPL-amplitude and sign, CD/UV-vis spectral wavelengths, and photodynamics of the aggregates, though the reasons for the anomaly are unsolved. However, these photophysical properties depend on (i the chemical natures of chiral and achiral molecules when used in solvent quantity, (ii clockwise and counterclockwise stirring operations, and (iii the order of addition of limonene and methanol to the chloroform solution.

Dependence of enthalpies of dissolution of β-alanyl-β-alanine on the composition of (water + alcohol) mixtures at 298.15 K

International Nuclear Information System (INIS)

Smirnov, Valeriy I.; Badelin, Valentin G.

2011-01-01

Highlights: · Enthalpies of dissolution of β-alanyl-β-alanine are measured in aqueous methanol, ethanol, 1-propanol and 2-propanol by calorimetry. · Standard values of dissolution and transfer enthalpies of β-alanyl-β-alanine and enthalpy coefficients of pair-wise interactions are calculated. · Dependences of the thermodynamic characteristics of dissolution of β-alanyl-β-alanine on the composition of (water + alcohol) mixtures are determined. - Abstract: The dissolution enthalpies of β-alanyl-β-alanine in aqueous methanol, ethanol, 1-propanol and 2-propanol solutions with an alcohol content up to 0.4 mole fractions have been measured calorimetrically at T = 298.15 K. The standard enthalpies of dissolution, Δ sol H o and transfer, Δ tr H o , of β-alanyl-β-alanine from water into mixed solvents and the enthalpy coefficients of pair-wise interactions, h xy , of β-alanyl-β-alanine with alcohol solvent molecules have been calculated. The results are discussed in terms of solute-solute and solute-solvent interactions.

Kinetic solvent isotope effects in the additions of bromine and 4-chlorobenzenesulfenyl chloride to alkenes and alkynes

International Nuclear Information System (INIS)

Modro, A.; Schmid, G.H.; Yates, K.

1979-01-01

The rates of bromination of selected alkenes and alkynes in methanol/methanol-d, acetic acid/acetic acid-d, and formic acid/formic acid-d have a nearly constant value of k/sub H//k/sub D/ = 1.23 +- 0.02. This kinetic solvent isotope effect is attributed to specific electrophilic solvation of the incipient bromide anion by hydrogen bonding in the rate-determining transition state. The rates of bromination were measured in two solvents having the same values of the solvent parameter Y but different nucleophilicities in order to assess the importance of nucleophilic solvation. Significant nucleophilic solvent assistance is found for only alkylacetylenes. The kinetic solvent isotope effects of the addition of 4-chlorobenzenesulfenyl chloride to selected alkenes and alkynes in acetic acid/acetic acid-d vary from 1.00 to 1.28. These data are consistent with two mechanisms: one involves a tetravalent sulfur intermediate while the second is the sulfur analogue of the S/sub N/2 mechanism

Optimization of the production of biodiesel by a commercial immobilized lipase in a solvent-free system using a response surface methodology

Directory of Open Access Journals (Sweden)

ZORICA KNEZEVIC

2008-02-01

Full Text Available Response surface methodology was used for the evaluation of the effects of various factors on the synthesis of biodiesel catalyzed with immobilized lipase from Rhizomucor miehei in a solvent-free system. The production of biodiesel was optimized and model response equations were obtained, enabling the prediction of biodiesel production from the values of the four main factors. It would seem that the reaction temperature and the amount of water predominantly determined the conversion process while the methanol/oil molar ratio had no significant influence on the reaction rate. The temperature and amount of water showed negative interactive effects on the observed reaction rate per amount of enzyme. However, there were no significant interactions among the other variables according to the test of statistical significance. The highest yield of 10.15 mol kg-1 enzyme was observed at 45 °C with a 6:1 methanol to oil molar ratio and with no added water in the system.

Experimental investigation on thermal performance of a closed loop pulsating heat pipe (CLPHP) using methanol and distilled water at different filling ratios

Science.gov (United States)

Rahman, Md. Lutfor; Swarna, Anindita Dhar; Ahmed, Syed Nasif Uddin; Perven, Sanjida; Ali, Mohammad

2016-07-01

Pulsating Heat Pipes, the new two-phase heat transfer devices, with no counter current flow between liquid and vapor have become a modern topic for research in the field of thermal management. This paper focuses on the performance of methanol and distilled water as working fluid in a closed loop pulsating heat pipe (CLPHP). This performances are compared in terms of thermal resistance, heat transfer co-efficient, and evaporator and condenser wall temperature with variable heat inputs. Methanol and Distilled water are selected for their lower surface tension, dynamic viscosity and sensible heat. A closed loop PHP made of copper with 2mm ID and 2.5mm OD having total 8 loops are supplied with power input varied from 10W to 60W. During the experiment the PHP is kept vertical, while the filling ratio (FR) is increased gradually from 40% to 70% with 10% increment. The optimum filling ratio for a minimum thermal resistance is found to be 60% and 40% for distilled water and methanol respectively and methanol is found to be the better working fluid compared to distilled water in terms of its lower thermal resistance and higher heat transfer coefficient.

A chromatographic determination of water in non-aqueous phases of solvent extraction systems

International Nuclear Information System (INIS)

Lyle, S.J.; Smith, D.B.

1975-01-01

The disadvantages of the Karl Fischer method for the determination of water in the non-aqueous phases of solvent extraction systems are pointed out, and a gas chromatographic method is described which is claimed to be potentially capable of overcoming these disadvantages. The method, as described, was developed to satisfy conditions relevant to measurement of the transfer rate of water from an aqueous phase into tri-n-butylphosphate in toluene, but it can be used for water determination in other solvent extraction systems. The apparatus used is described in detail. The concentration of water in water-saturated TBP was found to be 3.56 mol/litre, compared with a value of 3.55 obtained by Karl Fischer titration and previous literature values of 3.59 and 3.57. Measurements of water content in benzene solutions of long chain alkylamines were also sucessfully carried out. (U.K.)

Levels of lead in solvent and water-based paints manufactured in Pakistan

International Nuclear Information System (INIS)

Ikram, M.; Rauf, M.A.; Chotona, G.A.; Bukhari, N.

2000-01-01

The levels of lead in eight popular brands of solvent- and water-based paint manufactured locally in Pakistan are reported. The analysis was done using the flame Atomic Absorption Spectrophotometric method. The lead concentration was found to vary from 3.3 mg/kg to 13179 in different solvent-based brands, whereas the concentration of the metal was in the range of 1768 to less than 0.5mg/kg in water based paints. The lead concentrations were especially high in oil based green (maximum value of 13170 mg/kg) and yellow paints (maximum value of 84940 mg/kg). The corresponding higher concentration were observed in case of emerald (maximum value of 1768 mg/kg) and gray (maximum value of 542 mg/kg) paints in the water-based category. (author)

(Liquid + liquid) equilibrium of (dibutyl ether + methanol + water) at different temperatures

International Nuclear Information System (INIS)

Arce, Alberto; Rodriguez, Hector; Rodriguez, Oscar; Soto, Ana

2005-01-01

(Liquid + liquid) equilibrium data for the ternary system (dibutyl ether + methanol + water) were experimentally determined at T = (298.15, 308.15, and 318.15) K. The experimental results were correlated by means of the NRTL and UNIQUAC equations, the best results being achieved with the UNIQUAC equation, both for the individual correlations at each temperature and for the overall correlation considering all the three experimental data sets. The experimental tie-lines were also compared to the values predicted by the UNIFAC method

Determination of water traces in various organic solvents using Karl Fischer method under FIA conditions.

Science.gov (United States)

Dantan, N; Frenzel, W; Küppers, S

2000-05-31

Flow injection methods utilising the Karl Fischer (KF) reaction with spectrophotometric and potentiometric detection are described for the determination of the trace water content in various organic solvents. Optimisation of the methods resulted in an accessible (linear) working range of 0.01-0.2% water for many solvents studied with a typical precision of 1-2% R.S.D. Only 50 mul of organic solvent was injected and the sampling frequency was about 120 samples per h. Since the slopes of the calibration curves were different for different solvents appropriate calibration was required. Problems associated with spectrophotometric detection and caused by refractive index changes were pointed out and a nested-loop configuration was proposed to overcome this kind of interference. The potentiometric method with a novel flow-through detector cell was shown to surpass the performance of spectrophotometric detection in any respect. The characteristics of the procedures developed made them well applicable for on-line monitoring of technical solvent distillations in an industrial plant.

Ammonolysis-induced solvent removal: a facile approach for solidifying emulsion droplets into PLGA microspheres.

Science.gov (United States)

Kim, Jayoung; Hong, Dasom; Chung, Younglim; Sah, Hongkee

2007-12-01

An ammonolysis-based microencapsulation technique useful for the preparation of biodegradable microspheres was described in this study. A dispersed phase consisting of poly- d, l-lactide- co-glycolide, progesterone, and methyl chloroacetate was emulsified in an aqueous phase. Upon addition of ammonia solution, the emulsion droplets were quickly transformed into poly- d, l-lactide- co-glycolide microspheres laden with progesterone. Rapid solvent removal was accompanied by ammonolysis. The chemical reaction converted water-immiscible methyl chloroacetate to water-miscible chloroacetamide and methanol. Chloroacetamide formation was proved by (1)H NMR and ESI-MS studies. Thermogravimetric analysis showed that the microspheres contained only small amounts of residual methyl chloroacetate. Incorporation efficiencies of progesterone ranged from 64.3 +/- 1.1 to 72.8 +/- 0.3%, depending upon microsphere formulations. X-ray powder diffractometry analysis substantiated that no polymorphic transition of progesterone occurred during microencapsulation. To evaluate the feasibility of this new method against the commonly used microencapsulation method, microspheres were also prepared by a typical dichloromethane-based solvent evaporation process. The important attributes of microspheres prepared from both methods were characterized for comparison. The new ammonolysis-based microencapsulation process showed interesting features distinct from those of the solvent evaporation process. The microencapsulation process reported in this study might be applicable in loading pharmaceuticals into various polymeric microspheres.

(Solid + liquid) phase diagram for (indomethacin + nicotinamide)-methanol or methanol/ethyl acetate mixture and solubility behavior of 1:1 (indomethacin + nicotinamide) co-crystal at T = (298.15 and 313.15) K

International Nuclear Information System (INIS)

Sun, Xiaowei; Yin, Qiuxiang; Ding, Suping; Shen, Zhiming; Bao, Ying; Gong, Junbo; Hou, Baohong; Hao, Hongxun; Wang, Yongli; Wang, Jingkang; Xie, Chuang

2015-01-01

Highlights: • Ternary phase diagrams of (IMC + NCT)-methanol or methanol/ethyl acetate mixture at T = (298.15 and 313.15) K were measured. • The effects of temperature and introduced ethyl acetate on solid phase stability were discussed. • Solubility of (IMC + NCT) cocrystals was first correlated using a model considering solubility product and complexation. • Solubility of (IMC + NCT) cocrystals as a function of co-former concentration was evaluated. - Abstract: (Solid + liquid) equilibrium data for indomethacin (IMC) and nicotinamide (NCT) in both methanol (MeOH) and methanol/ethyl acetate (EA) mixture were determined using a static method at T = (298.15 and 313.15) K under atmospheric pressure. The 1:1 (IMC + NCT) co-crystal and IMC·MeOH were found in both systems under conditions investigated. The solubility of the 1:1 (IMC + NCT) co-crystal was correlated using a mathematical model consisting of both solubility product and a complexation process. Solubility of (IMC + NCT) co-crystals as a function of co-former (NCT) concentration was evaluated. It was found that temperature has a significant effect on the formation of methanol solvate in the systems investigated. Solvate formation could be suppressed either by increasing temperature or using solvent mixtures. Additionally, the solvent mixture could level out the solubility differences between IMC and NCT, resulting in larger and more symmetric regions for the (IMC + NCT) co-crystal, which would be helpful to the development of the co-crystallization process for the 1:1 (IMC + NCT) co-crystal

Information draft on the development of air standards for methanol

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-01-01

Methanol is a clear, colourless. very mobile liquid with a slightly alcoholic odour in pure form, but a repulsive pungent odour in crude form. Methanol is the raw material in the production of many gasoline additives, is used as a solvent or antifreeze in paint strippers, aerosol spray paints, wall paints, carburetor cleaners, and car windshield washer compounds. Methanol is one of the top pollutants by release quantities in Ontario, the highest release being generated by the pulp and paper industry. Other large emissions come from the plastics and synthetic resin industry. Total release to the air in Canada was 3,668 tonnes in 1996 and the top ten methanol emitting facilities were in Ontario. Methanol is readily absorbed through inhalation, ingestion and skin exposures. Once absorbed, it is oxidized to formaldehyde and then to formic acid. Common symptoms of exposure are visual disturbances, dizziness, nausea, vertigo, pain in the extremities, and headaches. No information was found as to the carcinogenicity of methanol to humans or animals. Current Ontario half-hour POI standard for methanol is 84,000 microgram/cubic meter and the 24-hour AAQC is 28,000 microgram/cubic meter. Both values were established more than 20 years ago. Review of relevant literature, summarized in this report, indicates that five US states have promulgated air quality guidelines or reference exposure levels for methanol, based on occupational exposure limits. The US Environmental Protection Agency is currently reviewing its reference concentration value for methanol. The World Health Organization and the Canadian federal government have not set air quality guidelines for methanol. 37 refs., 1 tab., appendix.

Co-solvents transesterification of cotton seed oil into biodiesel: Effects of reaction conditions on quality of fatty acids methyl esters

International Nuclear Information System (INIS)

Alhassan, Y.; Kumar, N.; Bugaje, I.M.; Pali, H.S.; Kathkar, P.

2014-01-01

Highlights: • Using co-solvent systems reduce reaction time by 60%. • Only small volume of co-solvent is required to improve the process. • Greater than 90% yields were obtained within the first 10 min. • Physico-chemical and fuel properties of FAMEs were within standard limits. • Acetone was found to be the best co-solvent for the transesterification. - Abstract: Solvent Technology, is gaining the interest of researchers in improving transesterification process recently. Transesterification of cotton seed oil into biodiesel using different mixtures of methanol with Diethyl Ether (DEE), Dichlorobenzene (CBN) or Acetone (ACT) co-solvent systems was conducted. Potassium hydroxide (KOH) was used as the catalyst all through. The reaction conditions optimized include; the molar ratio of co-solvent in methanol, reaction temperature and time. The catalyst concentration was also optimized. The optimization was based on the percentage yields of Fatty Acids Methyl Esters (FAMEs) produced. In addition, the effects of co-solvent systems on physico-chemical properties (Acid value and fatty acids composition) and fuel properties (viscosity, density and calorific value) were investigated as well. The result obtained, indicated 10% (v/v) addition of co-solvents CBN and ACT in methanol was the optimal volume. The optimal reaction temperature was 55 ° 0 C for 10 min when the catalyst concentration of 0.75% (w/w) weight of oil was used. Fuel properties were within the acceptable limit of ASTM and not significantly affected by the co-solvent systems except for the calorific value. It was concluded that the addition of co-solvent reduced the reaction time and improved some fuel properties of the biodiesel produced

Measurement and correlation of solubility of thiourea in two solvent mixtures from T = (283.15 to 313.15) K

International Nuclear Information System (INIS)

Wang, Yanmeng; Yin, Qiuxiang; Sun, Xiaowei; Bao, Ying; Gong, Junbo; Hou, Baohong; Wang, Yongli; Zhang, Meijing; Xie, Chuang; Hao, Hongxun

2016-01-01

Highlights: • Solubility of thiourea in methanol + ethanol and methanol + propanol was studied. • Experimental and calculated (NIBS/R-K) data are in a good agreement. • Interaction between solute and solvent are calculated by Molecular simulation. • Thermodynamic properties of both dissolving and mixing process are calculated. - Abstract: The solubility data of thiourea in methanol + ethanol mixtures and methanol + n-propanol mixtures were determined from T = (283.15 to 313.15) K by gravimetric method under atmospheric pressure. Effects of solvent composition and temperature on solubility of thiourea were discussed. Molecular simulation results indicate that solubility of thiourea will be influenced by interaction energy and a quantitative conclusion can be drawn from the modeling result. To extend the applicability of the solubility data, experimental solubility data in two kinds of binary solvent mixtures were correlated by the modified Apelblat equation, λ–h equation and (NIBS)/Redlich–Kister model. It was found that all the three models could satisfactorily correlate the experimental data and the (NIBS)/Redlich–Kister model could give better correlation results. Furthermore, thermodynamic properties of dissolving and mixing process of thiourea, including the enthalpy, the Gibbs energy and the entropy, were also calculated and analyzed.

SORPTION OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN TO SOILS FROM WATER/METHANOL MIXTURES

Science.gov (United States)

Sorption of 14C-labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to soils from water/methanol mixtures has been evaluated by batch shake testing. Uncontaminated soils from Times Beach, MO, were used in these experiments and ranged in fraction organic carbon (U...

Depolymerization of organosolv lignin using doped porous metal oxides in supercritical methanol

DEFF Research Database (Denmark)

Warner, Genoa; Hansen, Thomas Søndergaard; Riisager, Anders

2014-01-01

conversion to methanol-soluble products, without char formation, were based on copper in combination with other dopants based on relatively earth-abundant metals. Nearly complete conversion of lignin to bio-oil composed of monomers and low-mass oligomers with high aromatic content was obtained in 6. h at 310......An isolated, solvent-extracted lignin from candlenut (Aleurites moluccana) biomass was subjected to catalytic depolymerization in the presence of supercritical methanol, using a range of porous metal oxides derived from hydrotalcite-like precursors. The most effective catalysts in terms of lignin...