WorldWideScience

Sample records for hydrated organic solvent

  1. Theoretical study of chlorophyll a hydrates formation in aqueous organic solvents.

    Science.gov (United States)

    Ben Fredj, Arij; Ruiz-López, Manuel F

    2010-01-14

    A theoretical analysis of chlorophyll a (Chla) hydration processes in aqueous organic solvents has been carried out by means of quantum chemistry calculations. A detailed knowledge of the thermodynamics of these processes is fundamental in order to better understand the organization of chlorophyll molecules in vivo, specifically the structure of chlorophyll pairs in photosystems I and II. In the present work, we assumed a Chla model in which the phytyl chain is replaced by a methyl group. Calculations were performed at the B3LYP/6-31G(d) level corrected for basis set superposition errors and dispersion interaction energy. This computational scheme was previously shown to provide data close to MP2/6-311++(2d,2p) results. Solvents effects were taken into account using either continuum (for nonpolar solvents) or discrete-continuum (for polar coordinating solvents) methods. In the latter case, we first examined the structure of Chla in rigorously dry solutions. Two types of solvents were characterized according to Mg-atom coordination: In type I solvents (acetone, acetonitrile, DMSO), Mg exhibits five-coordination, whereas in type II solvents (THF, pyridine), Mg exhibits six-coordination. Hydration processes are quite dependent on solvent nature. In nonpolar or low-polarity solvents such as cyclohexane or chloroform, hydration is always exothermic and exergonic, despite a large entropy term that strongly opposes hydration. In polar solvents of type II, hydration is quite unfavorable, and essentially no hydrates are expected in these media, except perhaps at very large water concentrations (although, in such a case, the medium cannot be simply described as an organic solvent). In polar solvents of type I, the situation is intermediate, and dihydration is favorable in some cases (acetone, acetonitrile) and unfavorable in others (DMSO). It is interesting to note that first hydration processes in coordinating solvents (of either type I or type II), where a water molecule

  2. Organic solvent topical report

    Energy Technology Data Exchange (ETDEWEB)

    Cowley, W.L.

    1998-04-30

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

  3. Organic solvent topical report

    Energy Technology Data Exchange (ETDEWEB)

    COWLEY, W.L.

    1999-05-13

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

  4. 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.

  5. Multiple sclerosis and organic solvents

    DEFF Research Database (Denmark)

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

    1998-01-01

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

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

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Sansonetti, Sascha; Abildskov, Jens

    2012-01-01

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

  7. Effects of organic solvents on the barrier properties of human nail.

    Science.gov (United States)

    Smith, Kelly A; Hao, Jinsong; Li, S Kevin

    2011-10-01

    The effects of organic solvent systems on nail hydration and permeability have not been well studied. The objectives of the present study were to investigate the effects of binary aqueous organic solvent systems of ethanol (EtOH), propylene glycol (PPG), and polyethylene glycol 400 (PEG) on the barrier properties of nail plates. (3) H-water, (14) C-urea, and (14) C-tetraethylammonium ions were the probes in the nail uptake and transport experiments to study the effect(s) of organic solvents on nail hydration and permeability. Gravimetric studies were also performed as a secondary method to study nail hydration and the reversibility of the nail after organic solvent treatments. Both ungual uptake and transport were directly related to the concentration of the organic solvent in the binary systems. Partitioning of the probes into and transport across the nail decreased with an increase in the organic solvent concentration. These changes corresponded to the changes in solution viscosity and the barrier properties of the nail. In general, the effects for PPG and PEG were more pronounced than those for EtOH. Practically, these results suggest that organic solvents in formulations can increase nail barrier resistivity. Copyright © 2011 Wiley-Liss, Inc.

  8. Handbook of organic solvent properties

    CERN Document Server

    Smallwood, Ian

    2012-01-01

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

  9. Organic Solvent Tolerant Lipases and Applications

    Directory of Open Access Journals (Sweden)

    Shivika Sharma

    2014-01-01

    Full Text Available Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s could be performed in water-restricted organic media as organic solvent(s not only improve(s the solubility of substrate and reactant in reaction mixture but also permit(s the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented.

  10. [Neurotoxicity of organic solvents--recent findings].

    Science.gov (United States)

    Matsuoka, Masato

    2007-06-01

    In this review, the recent findings of central nervous system (CNS) or peripheral nervous system (PNS) dysfunction induced by occupational exposure to organic solvents are described. While acute, high-level exposure to almost all organic solvents causes the general, nonspecific depression of CNS, it is still not clear whether chronic, low-level occupational exposure causes the chronic neurological dysfunction which has been called "organic solvent syndrome", "painters syndrome", "psycho-organic syndrome" or "chronic solvent encephalopathy". At least at lower than occupational exposure limits, chronic and low-level organic solvent exposure does not appear to cause the "sy mptomatic" neurological dysfunction. The chronic, moderate- to high-level exposure to a few organic solvents (such as carbon disulfide, n-hexane and methyl n-butyl ketone) affects CNS or PNS specifically. The substitutes for chlorofluorocarbons, 2-bromopropane and 1-bromopropane were shown to have the peripheral nerve toxicity in the experimental animals. Shortly after these observations, human cases of 1-bromopropane intoxication with the dysfunction of CNS and PNS were reported in the United States. Neurological abnormalities in workers of a 1-bromopropane factory in China were also reported. Thus, the possible neurotoxicity of newly introduced substitutes for ozone-depleting solvents into the workplace must be considered. Enough evidences indicate that some common solvents (such as toluene and styrene) induce sensorineural hearing loss and acquired color vision disturbances in workers. In some studies using magnetic resonance imaging (MRI), cerebral atrophy, patchy periventricular hyperintensities and hypointensities in the basal ganglia were found in solvent-exposed workers as have been shown in toluene abusers (toluene leukoencephalopathy). Further studies using the neurobehavioral test batteries, neurophysiological measurements and advanced neuroimaging techniques are required to detect the

  11. Preparation of coal slurry with organic solvents.

    Science.gov (United States)

    Shin, Yu-Jen; Shen, Yun-Hwei

    2007-06-01

    In this study, various organic solvents were used to prepare coal slurries and the rheological and thermal properties of coal-organic solvent slurries were examined. Solvents with molecules containing unpaired electrons (high basicity) show high extraction power and cause swelling of coal. Therefore, coal-organic solvent slurries usually showed higher viscosities compared to coal-water slurry. In addition, coal slurries prepared by alcohols and cyclohexanone demonstrated lower settling rates but a high specific sedimentation volume presumably because these solvents swelled coal particles well and led to the formation of weak gel structures in the bulk. In addition, ethanol and cyclohexanone are capable of breaking a considerable amount of hydrogen bonds in coal and subsequently opening up the structures. Thus, more surface area is available for combustion and the combustion rate of coal slurries was increased.

  12. Organic solvent use in enterprises in Japan.

    Science.gov (United States)

    Nagasawa, Yasuhiro; Ukai, Hirohiko; Okamoto, Satoru; Samoto, Hajime; Itoh, Kenji; Moriguchi, Jiro; Sakuragi, Sonoko; Ohashi, Fumiko; Takada, Shiro; Kawakami, Tetsuya; Ikeda, Masayuki

    2011-01-01

    This study was initiated to elucidate possible changes in types of organic solvents (to be called solvents in short) used in enterprises in Japan through comparison of current solvent types with historical data since 1983. To investigate current situation in solvent use in enterprises, surveys were conducted during one year of 2009 to 2010. In total, workroom air samples in 1,497 unit workplaces with solvent use were analyzed in accordance with regulatory requirements. Typical use pattern of solvents was as mixtures, accounting for >70% of cases. Adhesives spreading (followed by adhesion) was relatively common in small-scale enterprises, whereas printing and painting work was more common in middle-scale ones, and solvent use for testing and research purpose was basically in large-scaled enterprises. Through-out printing, painting, surface coating and adhesive application, toluene was most common (being detected in 49 to 82% of workplaces depending on work types), whereas isopropyl alcohol was most common (49%) in degreasing, cleaning and wiping workplaces. Other commonly used solvents were methyl alcohol, ethyl acetate and acetone (33 to 37%). Comparison with historical data in Japan and literature-retrieved data outside of Japan all agreed with the observation that toluene is the most commonly used solvent. Application of trichloroethylene and 1,1,1-trichloroethane, once common in 1980s, has ceased to exist in recent years.

  13. Effects of Organic Solvents on the Barrier Properties of Human Nail

    OpenAIRE

    Smith, Kelly A.; HAO, JINSONG; Li, S. Kevin

    2011-01-01

    The effects of organic solvent systems on nail hydration and permeability have not been well studied. The objectives of the present study were to investigate the effects of binary aqueous organic solvent systems of ethanol (EtOH), propylene glycol (PPG), and polyethylene glycol 400 (PEG) on the barrier properties of nail plates. 3H–water, 14C–urea, and 14C–tetraethylammonium ions were the probes in the nail uptake and transport experiments to study the effect(s) of organic solvents on nail hy...

  14. Effects of Organic Solvents on the Barrier Properties of Human Nail

    OpenAIRE

    Smith, Kelly A; Hao, Jinsong; Li, S. Kevin

    2011-01-01

    The effects of organic solvent systems on nail hydration and permeability have not been well studied. The objectives of the present study were to investigate the effects of binary aqueous organic solvent systems of ethanol (EtOH), propylene glycol (PPG), and polyethylene glycol 400 (PEG) on the barrier properties of nail plates. 3H–water, 14C–urea, and 14C–tetraethylammonium ions were the probes in the nail uptake and transport experiments to study the effect(s) of organic solvents on nail hy...

  15. Solubility Behaviour of Cellulose in a Sodium Hydrate/Urea/Thiourea Aqueous Solvent

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shuai; CHENG Feng-wei; LI Fa-xue; YU Jian-yong; GU Li-xia

    2008-01-01

    Cellulose pulps were directly dissolved in a green solvent of sodium hydrate/urea/thiourea/water with different composition for the purpose to prepare new regenerated cellulose fibers or films. The results showed that the highest solubility of cellulose in the solvent with the composition of 8/8/6.5/77.5. The results revealed that the pulp feeding sequence, stirring rate, pre-treatment of pulp and pulp size affected the cellulose concentration in the green solvent. Accordingly, the more effective dissolution method was proposed in order to get higher concentration of cellulose. Furthermore, the properties of solution prepared by different kinds of pulps in the solvent were investigated by ARES rheometer. Rheological analyses indicated that all cellulose aqueous solutions in their high concentration were pseudoplastic fluids and sensitive to temperature and tended to transform to gel when temperature increased.

  16. Solvent-free fluidic organic dye lasers.

    Science.gov (United States)

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

    2013-05-06

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

  17. Green-solvent-processable organic solar cells

    Directory of Open Access Journals (Sweden)

    Shaoqing Zhang

    2016-11-01

    Full Text Available Solution-processable organic photovoltaics (OPV has emerged as a promising clean energy-generating technology due to its potential for low-cost manufacturing with a high power/weight ratio. The state-of-the-art OPV devices are processed by hazardous halogenated solvents. Fabricating high-efficiency OPV devices using greener solvents is a necessary step toward their eventual commercialization. In this review, recent research efforts and advances in green-solvent-processable OPVs are summarized, and two basic strategies including material design and solvent selection of light-harvesting layers are discussed. In particular, the most recent green-solvent-processable OPVs with high efficiencies in excess of 9% are highlighted.

  18. Effects of polar solvents on the fracture resistance of dentin: Role of water hydration

    Energy Technology Data Exchange (ETDEWEB)

    Ritchie, R O; Nalla, R K; Balooch, M; Ager III, J W; Kruzic, J J; Kinney, J H

    2004-12-10

    Although healthy dentin is invariably hydrated in vivo, from a perspective of examining the mechanisms of fracture in dentin, it is interesting to consider the role of water hydration. Furthermore, it is feasible that exposure to certain polar solvents, e.g., those found in clinical adhesives, can induce dehydration. In the present study, in vitro deformation and fracture experiments, the latter involving a resistance-curve (R-curve) approach (i.e., toughness evolution with crack extension), were conducted in order to assess changes in the constitutive and fracture behavior induced by three common solvents - acetone, ethanol and methanol. In addition, nanoindentation-based experiments to evaluate the deformation behavior at the level of individual collagen fibers and ultraviolet Raman spectroscopy to evaluate changes in bonding were performed. The results indicate a reversible effect of chemical dehydration, with increased fracture resistance, strength, and stiffness associated with lower hydrogen bonding ability of the solvent. These results are analyzed both in terms of intrinsic and extrinsic toughening phenomena to further understand the micromechanisms of fracture in dentin and the specific role of water hydration.

  19. Organic solvent nanofiltration: prospects and application

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, A V; Korneeva, G A; Tereshchenko, Gennadii F [A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow (Russian Federation)

    2008-11-30

    The key lines of research in a new field of the membrane science and technology, viz., organic solvent nanofiltration, are considered. The prospects for its use in chemical, petrochemical and food industries are discussed. Attention is focused on membranes developed for this method.

  20. Organic solvents in electromembrane extraction: recent insights

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  1. New Polymeric Membranes for Organic Solvent Nanofiltration

    KAUST Repository

    Aburabie, Jamaliah

    2017-05-01

    The focus of this dissertation was the development, synthesis and modification of polymers for the preparation of membranes for organic solvent nanofiltration. High chemical stability in a wide range of solvents was a key requirement. Membranes prepared from synthesized polymers as well as from commercial polymers were designed and chemically modified to reach OSN requirements. A solvent stable thin-film composite (TFC) membrane is reported, which is fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate. The membranes exhibited high fluxes towards solvents like THF, DMF and DMSO ranging around 20 L/m2 h at 5 bar with a MWCO of around 1000 g/mol. Ultrafiltration PTSC membranes were prepared by non-solvent induced phase separation and crosslinked with GPTMS. The crosslinking reaction was responsible for the formation of an inorganic-type-network that tuned the membrane pore size. The crosslinked membranes acquired high solvent stability in DMSO, DMF and THF with a MWCO above 1300 g/mol. Reaction Induced Phase Separation (RIPS) was introduced as a new method for the preparation of skinned asymmetric membranes. These membranes have two distinctive layers with different morphologies both from the same polymer. The top dense layer is composed of chemically crosslinked polymer chains while the bottom layer is a porous structure formed by non-crosslinked polymer chains. Such membranes were tested for vitamin B12 in solvents after either crosslinking the support or dissolving the support and fixing the freestanding membrane on alumina. Pebax® 1657 was utilized for the preparation of composite membranes by simple coating. Porous PAN membranes were coated with Pebax® 1657 which was then crosslinked using TDI. Crosslinked Pebax® membranes show high stability towards ethanol, propanol and acetone. The membranes were also stable in DMF once crosslinked PAN supports were used. Sodium alginate polymer was investigated for the preparation of thin film composite

  2. Indentation of polydimethylsiloxane submerged in organic solvents

    OpenAIRE

    Hu, Yuhang; Chen, Xin; Whitesides, George McClelland; Vlassak, Joost J.; Suo, Zhigang

    2011-01-01

    This work uses a method based on indentation to characterize a polydimethylsiloxane (PDMS) elastomer submerged in an organic solvent (decane, heptane, pentane, or cyclohexane). An indenter is pressed into a disk of a swollen elastomer to a fixed depth, and the force on the indenter is recorded as a function of time. By examining how the relaxation time scales with the radius of contact, one can differentiate the poroelastic behavior from the viscoelastic behavior. By matching the relaxation c...

  3. Organic Solvent Tropical Report [SEC 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    COWLEY, W.L.

    2000-06-21

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an unmitigated organic solvent fire is within risk evaluation guidelines.

  4. Hydration of gelatin molecules in glycerol-water solvent and phase diagram of gelatin organogels.

    Science.gov (United States)

    Sanwlani, Shilpa; Kumar, Pradip; Bohidar, H B

    2011-06-09

    We present a systematic investigation of hydration and gelation of the polypeptide gelatin in water-glycerol mixed solvent (glycerol solutions). Raman spectroscopy results indicated enhancement in water structure in glycerol solutions and the depletion of glycerol density close to hydration sheath of the protein molecule. Gelation concentration (c(g)) was observed to decrease from 1.92 to 1.15% (w/v) while the gelation temperature (T(g)) was observed to increase from 31.4 to 40.7 °C with increase in glycerol concentration. Data on hand established the formation of organogels having interconnected networks, and the universal gelation mechanism could be described through an anomalous percolation model. The viscosity of sol diverged as η ∼ (1 - c(g)/c)(-k) as c(g) was approached from below (c c(g)). It is important to note that values determined for critical exponents k and t were universal; that is, they did not depend on the microscopic details. The measured values were k = 0.38 ± 0.10 and t = 0.92 ± 0.17 whereas the percolation model predicts k = 0.7-1.3 and t = 1.9. Isothermal frequency sweep studies showed power-law dependence of gel storage modulus (G') and loss modulus (G'') on oscillation frequency ω given as G'(ω) ∼ ω(n') and G''(ω) ∼ ω(n''), and consistent with percolation model prediction it was found that n' ≈ n'' ≈ δ ≈ 0.73 close to gelation concentration. We propose a unique 3D phase diagram for the gelatin organogels. Circular dichroism data revealed that the gelatin molecules retained their biological activity in these solvents. Thus, it is shown that the thermomechanical properties of these organogels could be systematically tuned and customized as per application requirement.

  5. Preparation of graphene sponge by vapor phase reduction for oil and organic solvent removal

    Science.gov (United States)

    Wu, Ruihan; Yu, Baowei; Jin, Xinyan; Liu, Xiaoyang; Bai, Yitong; Chen, Lingyun; Ming, Zhu; Yang, Hua; Yang, Sheng-Tao; Luo, Jianbin

    2016-10-01

    Due to the porous structure and hydrophobicity, graphene sponge has huge adsorption capacity for oils and organic solvents. In this study, we reported that graphene sponge could be prepared by vapor phase reduction (denoted as VPRGS) for oil and organic solvent removal. Graphene oxide was lyophilized and reduced by steamy hydrazine hydrate to produce VPRGS. VPRGS had huge capacity for oils and organic solvents (72–224 g g‑1). In particular, the adsorption capacity for crude oil reached 165 g g‑1, suggesting that VPRGS could be applied in oil leakage remediation. VPRGS could treat pollutants both in pure liquid form and in the simulated sea water, where the hydrophobic nature of VPRGS allowed the floating of VPRGS on simulated sea water. VPRGS could be easily regenerated without obvious capacity loss up to 9 cycles. The implications to the applications of VPRGS in oil/water separation and water remediation are discussed.

  6. Effect of the hydration state of supports before lyophilization on subtilisin-A activity in organic media.

    Science.gov (United States)

    Kim, J; Kim, B G

    1996-06-20

    Subtilisin-A was colyophilized with various types of support materials, such as Amberlite IRC-50, Celite545, chitosan, DEAE-cellulose, DOWEX-1, zeolite, glass bead, and polystyrene. The colyophilized enzyme was used for the optical resolution of racemic 1-phenylethylamine with 2,2,2-trifluoroethylbutyrate in 3-methyl-3-pentanol. The enzyme activity in organic media changed dramatically according to the hydration state of the support materials before lyophilization. This effect was especially marked with supports of high water capacity (aquaphilicity), such as chitosan and DEAE-cellulose. By hydrating these supports of high aquaphilicity prior to lyophilization, subtilisin-A activity in organic media increased ca. 4-8 times, depending upon the supports used. This result suggests that the hydration state of aquaphilic support materials for colyophilization is critical to determining enzyme activity in organic solvents.

  7. Effect of some organic solvents on oxidative phosphorylation in rat liver mitochondria: Choice of organic solvents.

    Science.gov (United States)

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

    2013-12-01

    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 showed least effect on oxidative phosphorylation with an IC50 value of 13.3±1.1% (v/v), followed by methanol (IC50 value 8.3±1.0), ethanol (IC50 value 4.6±1.1), acetone (IC50 value 4.3±1.0) and finally acetonitrile (IC50 value 2.1±1.0). All the organic solvents showed modulatory effects on 2,4-dinitrophenol (DNP) mediated inhibition of oxidative phosphorylation with potentiation of the action of DNP. Acetonitrile showed the highest potentiation effect followed by acetone, ethanol, methanol, and DMSO in presence of DNP. The use of organic solvents for investigation of the effects of compounds on oxidative phosphorylation in mitochondria should therefore include the use of relevant concentrations of the organic solvent in order to validate the contribution.

  8. Measurement of oxygen transfer from air into organic solvents

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias

    2016-01-01

    applications). Subsequently, we measured the oxygen transfer rates from air into these organic solvents. Conclusion The measurement of oxygen transfer rates from air into organic solvents using the dynamic method was established using the solvent resistant optical sensor. The feasibility of online oxygen...... biological reactions require the supply of oxygen, most normally from air. However, reliable on-line measurements of oxygen concentration in organic solvents (and hence oxygen transfer rates from air to the solvent) has to date proven impossible due limitations in the current analytical methods. Results...

  9. NMR microscopy of tissue in organic and mixed solvents

    OpenAIRE

    Macura Slobodan; Mishra Prasanna K.; Gamez Jeffrey D.; Pirko Istvan

    2013-01-01

    We propose to use organic and mixed solvents for nuclear magnetic resonance microscopy of fixed tissue as a means for improving image information content. NMR properties of some standard solvents (methanol, acetone, DMSO) and solvents in use for tissue processing in pathology (xylenes, paraffin, ‘Clearify’) have been measured, reviewed, and analyzed. It was found that DMSO and paraffin are very useful solvents that provide images of better quality than thos...

  10. A newly isolated organic solvent tolerant Staphylococcus saprophyticus M36 produced organic solvent-stable lipase.

    Science.gov (United States)

    Fang, Yaowei; Lu, Zhaoxin; Lv, Fengxia; Bie, Xiaomei; Liu, Shu; Ding, Zhongyang; Xu, Weifeng

    2006-12-01

    Thirty-eight high lipase activity strains were isolated from soil, seawater, and Brassica napus. Among them, a novel organic solvent tolerant bacterium (strain M36) was isolated from the seawater in Jiangsu, China. Isolate M36 was able to grow at high concentration of benzene or toluene up to 40% (vol/vol), and later identified as Staphylococcus saprophyticus by biochemical test and 16s ribosomal DNA sequence. No work on Staphylococcus producing lipase with organic solvent tolerance has been reported so far. The lipase of strain M36 whose activity in liquid medium was 42 U mL(-1) at 24-h incubation time was stable in the presence of 25% (vol/vol) p-xylene, benzene, toluene, and hexane.

  11. Interactions of Organic Additives with Ionic Crystal Hydrates

    Science.gov (United States)

    Füredi-Milhofer, H.; Sikirić, M.; Tunik, L.; Filipović-Vinceković, N.; Garti, N.

    The interactions of two groups of hydrated model crystals, calcium hydrogenphosphate dihydrate (DCPD) vs. octacalcium phosphate (OCP) and calcium oxalate monohydrate (COM) vs. calcium oxalate dihydrate (COD) with different organic additives are considered. DCPD precipitates as platelet-like crystals with the dominant faces shielded by hydrated layers and charged lateral faces. In the second system COM has charged surfaces, while all faces of COD are covered with layers containing water molecules. The organic molecules tested include negatively charged, flexible and rigid small and macromolecules (glutamic and aspartic acid, citrate, hexaammonium polyphosphate, phytate and polyaspartate) and anionic surfactants (sodium dodecyl sulphate, SDS, sodium diisooctyl sulfosuccinate, AOT, sodium cholate NaC and disodium oleoamido PEG-2 sulfosuccinate, PEG). Two types of effects have been demonstrated: (1) Effect on crystal growth morphology: Flexible organic molecules with high charge density and anionic surfactants affected the growth morphology of DCPD and COM by selectively interacting with the charged lateral faces while rigid molecules (phytate, polyaspartate) specifically recognized the dominant (010) face of DCPD due to structural and stereochemical compatibility. (2) Effect on phase composition: Anionic surfactants at concentrations above the cmc promoted growth of OCP and COD respectively by selectively adsorbing at, and inhibiting growth oif nuclei of DCPD and/or COM, which were dominant in the respective control systems. The effect was especially pronounced in the calcium oxalate precipitation system, where in some cases complete reversal of the phase composition occurred. The important role of the hydrated layer, as part of the structure of the investigated crystal hydrates, in the above crystal additive interactions is discussed.

  12. Molecular dynamics simulations of trehalose as a 'dynamic reducer' for solvent water molecules in the hydration shell.

    Science.gov (United States)

    Choi, Youngjin; Cho, Kum Won; Jeong, Karpjoo; Jung, Seunho

    2006-06-12

    Systematic computational work for a series of 13 disaccharides was performed to provide an atomic-level insight of unique biochemical role of the alpha,alpha-(1-->1)-linked glucopyranoside dimer over the other glycosidically linked sugars. Superior osmotic and cryoprotective abilities of trehalose were explained on the basis of conformational and hydration characteristics of the trehalose molecule. Analyses of the hydration number and radial distribution function of solvent water molecules showed that there was very little hydration adjacent to the glycosidic oxygen of trehalose and that the dynamic conformation of trehalose was less flexible than any of the other sugars due to this anisotropic hydration. The remarkable conformational rigidity that allowed trehalose to act as a sugar template was required for stable interactions with hydrogen-bonded water molecules. Trehalose made an average of 2.8 long-lived hydrogen bonds per each MD step, which was much larger than the average of 2.1 for the other sugars. The stable hydrogen-bond network is derived from the formation of long-lived water bridges at the expense of decreasing the dynamics of the water molecules. Evidence for this dynamic reduction of water by trehalose was also established based on each of the lowest translational diffusion coefficients and the lowest intermolecular coulombic energy of the water molecules around trehalose. Overall results indicate that trehalose functions as a 'dynamic reducer' for solvent water molecules based on its anisotropic hydration and conformational rigidity, suggesting that macroscopic solvent properties could be modulated by changes in the type of glycosidic linkages in sugar molecules.

  13. An evaluation of the applicability of the EPA Organic Leachate Model to leaching of solvent and non-solvent wastes

    OpenAIRE

    Bosserman, Carolyn Whitney

    1989-01-01

    The author evaluated the applicability of the Environmental Protection Agency's Organic Leachate Model to wastes containing organic solvents and other organic compounds ("non-solvents"), and determined that the model tends to overestimate the leaching of organic solvents and other organic compounds. Furthermore, when evaluated for its ability to predict leaching of organic compounds, the model was found to predict the leaching of organic solvent compounds with some accuracy, with a correlatio...

  14. Substitution of Organic Solvents in Selected Industrial Cleaning Processes

    DEFF Research Database (Denmark)

    Jacobsen, Thomas; Rasmussen, Pia Brunn

    1997-01-01

    Volatile organic solvents (VOC)are becoming increasingly unwanted in industrial processes. Substitution of VOC with non-volatile, low-toxic compounds is a possibility to reduce VOC-use. It has been successfully demonstrated, that organic solvents used in cleaning processes in sheet offset printing...

  15. Dispersion and separation of nanostructured carbon in organic solvents

    Science.gov (United States)

    Landi, Brian J. (Inventor); Raffaelle, Ryne P. (Inventor); Ruf, Herbert J. (Inventor); Evans, Christopher M. (Inventor)

    2011-01-01

    The present invention relates to dispersions of nanostructured carbon in organic solvents containing alkyl amide compounds and/or diamide compounds. The invention also relates to methods of dispersing nanostructured carbon in organic solvents and methods of mobilizing nanostructured carbon. Also disclosed are methods of determining the purity of nanostructured carbon.

  16. Calorimetric Investigation of Hydrogen Bonding of Formamide and Its Methyl Derivatives in Organic Solvents and Water

    Science.gov (United States)

    Varfolomeev, Mikhail A.; Rakipov, Ilnaz T.; Solomonov, Boris N.

    2013-04-01

    Formamide and its derivatives have a large number of practical applications; also they are structural fragments of many biomolecules. Hydrogen bonds strongly affect their physicochemical properties. In the present work a calorimetric study of formamide and its methyl derivatives was carried out. Enthalpies of solution at infinite dilution of formamide, N-methylformamide, and N, N-dimethylformamide in organic solvents at 298.15 K were measured. The relationships between the obtained enthalpies of solvation and the structure of the studied compounds were observed. Hydrogen-bond enthalpies of amides with chlorinated alkanes, ethers, ketones, esters, nitriles, amines, alcohols, and water were determined. The strength of hydrogen bonds of formamide, N-methylformamide, and N, N-dimethylformamide with proton donor solvents is practically equal. Enthalpies of hydrogen bonds of formamide with the proton acceptor solvents are two times larger in magnitude than the enthalpies of N-methylformamide. The process of hydrogen bonding of amides in aliphatic alcohols and water is complicated. The obtained enthalpies of hydrogen bonding in aliphatic alcohols vary considerably from the amide structure due to the competition between solute-solvent and solvent-solvent hydrogen bonds. Fourier transform infrared spectroscopic measurements were carried out to explain the calorimetric data. Hydration enthalpies of methyl derivatives of formamides contain a contribution of the hydrophobic effect. New thermochemical data on the hydrogen bonding of formamides may be useful for predicting the properties of biomacromolecules.

  17. Psychomotor Effects of Mixed Organic Solvents on Rubber Workers

    Directory of Open Access Journals (Sweden)

    O Aminian

    2014-04-01

    Full Text Available Background: Exposure to organic solvents is common among workers.Objective: To assess neurobehavioral effects of long-term exposure to organic solvents among rubber workers in Tehran, Iran.Methods: Across-sectional study was conducted on 223 employees of a rubber industry. The participants completed a data collection sheet on their occupational and medical history, and demographic characteristics including age, work experience, education level; they performed 6 psychiatric tests on the neurobehavioral core test battery (NCTB that measure simple reaction time, short-term memory (digit span, Benton, eye-hand coordination (Purdue pegboard, pursuit aiming, and perceptual speed (digit symbol.Results: Workers exposed and not exposed to organic solvents had similar age and education distribution. The mean work experience of the exposed and non-exposed workers was 5.9 and 4.4 years, respectively. The exposed workers had a lower performance compared to non-exposed workers in all psychomotor tests. After controlling for the confounders by logistic regression analysis, it was found that exposure to organic solvents had a significant effect on the results of digit symbols, digit span, Benton, aiming, and simple reaction time tests. No significant effect was observed in pegboard test.Conclusion: Occupational exposure to organic solvent can induce subtle neurobehavioral changes among workers exposed to organic solvents; therefore, periodical evaluation of the central nervous system by objective psychomotor tests is recommended among those who are chronically exposed to organic solvents.

  18. Graphene/polyester staple composite for the removal of oils and organic solvents

    Science.gov (United States)

    Wu, Ruihan; Yu, Baowei; Liu, Xiaoyang; Li, Hongliang; Bai, Yitong; Ming, Zhu; Chen, Lingyun; Yang, Sheng-Tao; Chang, Xue-Ling

    2016-06-01

    Spongy graphene has been widely applied in oil removal. However, spongy graphene is hardly applicable for crude oil removal, because the complexity and high viscosity of crude oil. Herein, we reported that graphene/polyester staple composite (GPSC) could be used for the removal of oils and organic solvents, in particular crude oil. Graphene oxide was in situ reduced in the presence of polyester staple by hydrazine hydrate to form GPSC. GPSC efficiently adsorbed oils and organic solvents with high adsorption capacities. Demonstrations of treating pure oils and those in simulated sea water by GPSC were successfully performed. Due to the loose structure, GPSC adsorbed crude oil quickly with an adsorption capacity of 52 g g-1. During the regeneration, the adsorption capacity of GPSC retained around 78% of the initial capacity up to 9 cycles. The implication to the applications of GPSC in water remediation is discussed.

  19. Resolution of Racemic Acids, Esters and Amines by Candida rugosa Lipase in Slightly Hydrated Organic Media

    Directory of Open Access Journals (Sweden)

    Andrés R. Alcántara

    2004-01-01

    Full Text Available Commercial crude lipase from Candida rugosa is widely used as a biocatalyst in the resolution of racemic mixtures and in organic synthesis in slightly hydrated organic solvents. In many cases, reproducible results are not obtained when the same crude lipase is used, but from different suppliers of lots, this being due to the presence of different isoenzymes. The current work addresses this problem and strategies to overcome it. The yeast Candida rugosa ATCC 14380 was cultivated in a minimal culture medium, using different substances as inducers and carbon sources. The percentage of inducer that gave the optimum productivity of extracellular lipases was determined. Lyophilized extracellular enzymes were characterized by SDS-PAGE electrophoresis and isoelectric focusing (IEF. Depending on the nature of the carbon source, different isoenzymes were produced in various proportions. These samples were partially purified by different methodologies, including dialysis, adsorption chromatography and precipitation with ammonium sulfate or organic solvents. These characterizations allowed us to explain the relative catalytic activity of different samples, showing that in biocatalysis enzymes should not be treated simply as a »white magic powder« that can solve all the challenges in organic synthesis. Heptyl oleate synthesis, alcoxycarbonylation of amines and hydrolysis of the ester of ketoprofen are excellent reaction tests for the evaluation of lipase samples as biocatalysts.

  20. Alternatives to Organic Solvents in Industrial Cleaning Processes

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    1998-01-01

    cleaning agents in offset printing companies instead of volatile, toxic organic solvents. The present study is based on a project with the aim of defining other industrial processes, where organic solvents used for cleaning or degreasing can be replaced by non-volatile, low-toxic products, which are based...... on esters from fatty acids of vegetable origin (vegetable esters - VE).The study indicates that industrial cleaning/degreasing with organic solvents may be substituted with VEs on metal surfaces and on some coated surfaces, in manufacture of paints and inks, use of paints, use of inks (printing), metal...

  1. Cooling crystallization of Indomethacin from different organic solvents

    DEFF Research Database (Denmark)

    Malwade, Chandrakant Ramkrishna; Qu, Haiyan

    In the present work, crystallization of an anti-inflammatory drug Indomethacin (IMC) from different organic solvents was investigated concerning the polymorphism and particulate properties of the final product. Initially, the solvents were screened by measuring solubility of IMC at temperatures 1...

  2. NMR microscopy of tissue in organic and mixed solvents

    Directory of Open Access Journals (Sweden)

    Macura Slobodan

    2013-01-01

    Full Text Available We propose to use organic and mixed solvents for nuclear magnetic resonance microscopy of fixed tissue as a means for improving image information content. NMR properties of some standard solvents (methanol, acetone, DMSO and solvents in use for tissue processing in pathology (xylenes, paraffin, ‘Clearify’ have been measured, reviewed, and analyzed. It was found that DMSO and paraffin are very useful solvents that provide images of better quality than those obtained in water (neutralized formalin buffer. This is illustrated on the formalin fixed mouse brain sections imaged at 16.4 teslas (700 MHz.

  3. Mechanism of transport and distribution of organic solvents in blood

    Science.gov (United States)

    Lam, C. W.; Galen, T. J.; Boyd, J. F.; Pierson, D. L.

    1990-01-01

    Little is known about the mechanism of transport and distribution of volatile organic compounds in blood. Studies were conducted on five typical organic solvents to investigate how these compounds are transported and distributed in blood. Groups of four to five rats were exposed for 2 hr to 500 ppm of n-hexane, toluene, chloroform, methyl isobutyl ketone (MIBK), or diethyl ether vapor; 94, 66, 90, 51, or 49%, respectively, of these solvents in the blood were found in the red blood cells (RBCs). Very similar results were obtained in vitro when aqueous solutions of these solvents were added to rat blood. In vitro studies were also conducted on human blood with these solvents; 66, 43, 65, 49, or 46%, respectively, of the added solvent was taken up by the RBCs. These results indicate that RBCs from humans and rats exhibited substantial differences in affinity for the three more hydrophobic solvents studied. When solutions of these solvents were added to human plasma and RBC samples, large fractions (51-96%) of the solvents were recovered from ammonium sulfate-precipitated plasma proteins and hemoglobin. Smaller fractions were recovered from plasma water and red cell water. Less than 10% of each of the added solvents in RBC samples was found in the red cell membrane ghosts. These results indicate that RBCs play an important role in the uptake and transport of these solvents. Proteins, chiefly hemoglobin, are the major carriers of these compounds in blood. It can be inferred from the results of the present study that volatile lipophilic organic solvents are probably taken up by the hydrophobic sites of blood proteins.

  4. Solvent Selection for Recrystallization: An Undergraduate Organic Experiment.

    Science.gov (United States)

    Baumann, Jacob B.

    1979-01-01

    This experiment develops the students' ability to carry out a simple recrystallization effectively, and demonstrates how a solvent may be selected or rejected for the recrystallization of a specific organic compound. (Author/BB)

  5. Exposure to organic solvents during cosmetic finishing of cars

    National Research Council Canada - National Science Library

    Bråtveit, M; Moen, B E

    2001-01-01

    The objectives of this study were to assess the exposure to organic solvents during degreasing, washing and polishing of cars, and to obtain information about acute health symptoms in car-finishing workers...

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

    OpenAIRE

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

    2012-01-01

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

  7. Acute toxicity of organic solvents on Artemia salina

    Energy Technology Data Exchange (ETDEWEB)

    Barahona-Gomariz, M.V.; Sanz-Barrera, F.; Sanchez-Fortun, S. (Complutense Univ. of Madrid (Spain))

    1994-05-01

    Organic solvents can make their way into the environment as industrial wastes and components of pesticide formulation. In laboratory bioassays, the use of organic formulations. In laboratory bioassays, the use of organic solvents is often unavoidable, since many pesticides and organic pollutants have low water solubility and must be dissolved in organic solvents prior to addition into experimental systems. In the toxicant bioassays, invertebrates with special reference to aquatic arthropod species are of recent interest as test models due to the need for developing nonmammalian test systems. Toxic effects of organic solvents have been tested with a few aquatic species, but information on the comparative toxicity of solvents towards Artemia salina is not available. Artemia salina have, within recent years, gained popularity as test organisms for short-term toxicity testing. Because Artemia salina exhibit rapid development and growth within 48 hr after hatch, their potential as a model organism for toxicology screening has been considered. To do this, synchronous populations of Artemia salina at different development intervals must be available.

  8. Organic free radicals in clathrate hydrates investigated by muon spin spectroscopy.

    Science.gov (United States)

    Percival, Paul W; Mozafari, Mina; Brodovitch, Jean-Claude; Chandrasena, Lalangi

    2014-02-20

    Very little is known about the behavior of free H atoms and small organic radicals inside clathrate hydrate structures despite the relevance of such species to combustion of hydrocarbon hydrates. Muonium is an H atom analog, essentially a light isotope of hydrogen, and can be used to probe the chemistry of H atoms and transient free radicals. We demonstrate the first application of muon spin spectroscopy to characterize radicals in clathrate hydrates. Atomic muonium was detected in hydrates of cyclopentane and tetrahydrofuran, and muoniated free radicals were detected in the hydrates of cyclopentene and 2,5-dihydrofuran, indicating rapid addition of muonium to the organic guest. Muon avoided level-crossing spectra of the radicals in hydrates are markedly different to those of the same radicals in pure organic liquids at the same temperature, and this can be explained by limited mobility of the enclathrated radicals, leading to anisotropy in the hyperfine interactions.

  9. Affinity Solvents for Intensified Organics Extraction: Development Challenges and Prospects

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In most organics extraction processes, the commonly used solvents employ solely physical interactions. Therefore, for the recovery and purification of products from complex mixtures, the selectivity and/or capacity of classical solvents towards the desired solutes is usually insufficient, enforcing the need for complex and thus expensive separation schemes. Significant simplification and cost-reduction can be achieved when affinity solvents would be available that are able to recognize the solutes of interest by their molecular structure. The main development challenges to establish such affinity solvents are: Selection and incorporation of molecular recognition and complexation capabilities; Evaluation of extraction capabilities; Efficient recovery and recycling of the affinity solvents; Implementation in industrial extraction equipment. This paper presents how these development challenges are addressed at the University of Twente, going all the way from affinity solvent design and synthesis, via high throughput screening and characterization up to pilot plant evaluation. Essential in the successful development of affinity solvents are structural cooperations with molecular chemists and custom synthesis companies for their design and synthesis. The various aspects are illustrated by several examples where newly developed environmentally benign affinity solvents appeared able to create major breakthroughs. The applications addressed involve oxygenates, sugars, and pharmaceutical ingredients, such as optical isomers and biomolecules.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  11. Dispersion of Single-Walled Carbon Nanotubes in Organic Solvents

    OpenAIRE

    Cheng, Qiaohuan

    2010-01-01

    This thesis contains a systematic study of the dispersion of pristine HiPco Single Walled Carbon Nanotubes (SWNTs) in a series of organic solvents. A double beamed UV-Vis-NIR absorption spectrometer coupled with an integrating sphere was employed to demonstrate the dispersibility of SWNTs in different solvents. Raman Spectroscopy and Atomic Force Microscopy (AFM) were used to confirm the debundling and exfoliation of SWNTs aggregates. An investigation of the solubility of SWNTs in four chlori...

  12. Phase Behavior of Mixtures of Ionic Liquids and Organic Solvents

    DEFF Research Database (Denmark)

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

    2010-01-01

    A corresponding-states form of the generalized van der Waals equation, previously developed for mixtures of an ionic liquid and a supercritical solute, is here extended to mixtures including an ionic liquid and a solvent (water or organic). Group contributions to characteristic parameters...... solvents. Here we show results for heavier and more-than-sparingly solutes such as carbon dioxide and propane in ionic liquids....

  13. Solvent

    OpenAIRE

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

    2013-01-01

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

  14. Measurement of oxygen transfer from air into organic solvents

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias;

    2016-01-01

    Background:The use of non-aqueous organic media is becoming increasingly important in many biotechnological applications in order to achieve process intensification. Such media can be used for example to directly extract poorly water-soluble toxic products from fermentations. Likewise many...... measurements in organic solvents has also been demonstrated, paving the way for new opportunities in process control....

  15. Organic Solvent Tolerant Lipases and Applications

    National Research Council Canada - National Science Library

    Sharma, Shivika; Kanwar, Shamsher S

    2014-01-01

    ... the hydrolysis of triacylglycerol to glycerol and fatty acids [2]. Lipases find potential applications in bioprocesses largely due to their availability and stability in organic as well as in aqueo...

  16. Alternatives to Organic Solvents in Industrial Cleaning Processes

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    1998-01-01

    cleaning agents in offset printing companies instead of volatile, toxic organic solvents. The present study is based on a project with the aim of defining other industrial processes, where organic solvents used for cleaning or degreasing can be replaced by non-volatile, low-toxic products, which are based...... on esters from fatty acids of vegetable origin (vegetable esters - VE).The study indicates that industrial cleaning/degreasing with organic solvents may be substituted with VEs on metal surfaces and on some coated surfaces, in manufacture of paints and inks, use of paints, use of inks (printing), metal...... industry, and vehicle repair and maintenance. There are, however, other elements that influence the possibility to substitute. The requirements to the resulting surface, depending on the following treatment of the surface. The character of the soilings to be removed. The possible presence of other...

  17. Substitution of Organic Solvents in Selected Industrial Cleaning Processes

    DEFF Research Database (Denmark)

    Jacobsen, Thomas; Rasmussen, Pia Brunn

    1997-01-01

    Volatile organic solvents (VOC)are becoming increasingly unwanted in industrial processes. Substitution of VOC with non-volatile, low-toxic compounds is a possibility to reduce VOC-use. It has been successfully demonstrated, that organic solvents used in cleaning processes in sheet offset printing......, and industrial coating processes are likely candidates for substitution of VOC with VOFA. Requirements to the resulting surfaces may, however, hinder the replacement. This is especially important when the surface has to be coated in a subsequent step....

  18. Measurement and control of water content of organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Goderis, H.L.; Fouwe, B.L.; Van Cauwenbergh, S.M.; Tobback, P.P.

    1986-06-01

    An isotopic dilution procedure is described for the quantitative determination of the solubility of water in organic solvents as a function of the relative humidity at which the sample is equilibrated. /sup 3/H/sub 2/O is used as a tracer, and the relative humidity conditions are realized by incubation of the organic solvent above a saturated salt solution having a known water activity. The technique is applicable independent of the concentration range of water present, the minimum amount of moisture being only limited by the concentration of the tritium label used. Solubility isotherms of water in hydrocarbon solvents such as n-hexane are sigmoidal in shape, reflecting cooperative effects in the solubilization of water molecules at the higher relative humidity portion of the curve. Solubility increases with increasing temperature.

  19. Transitioning organic synthesis from organic solvents to water. What's your E Factor?

    Science.gov (United States)

    Lipshutz, Bruce H.; Ghorai, Subir

    2014-01-01

    Traditional organic chemistry, and organic synthesis in particular, relies heavily on organic solvents, as most reactions involve organic substrates and catalysts that tend to be water-insoluble. Unfortunately, organic solvents make up most of the organic waste created by the chemical enterprise, whether from academic, industrial, or governmental labs. One alternative to organic solvents follows the lead of Nature: water. To circumvent the solubility issues, newly engineered “designer” surfactants offer an opportunity to efficiently enable many of the commonly used transition metal-catalyzed and related reactions in organic synthesis to be run in water, and usually at ambient temperatures. This review focuses on recent progress in this area, where such amphiphiles spontaneously self-aggregate in water. The resulting micellar arrays serve as nanoreactors, obviating organic solvents as the reaction medium, while maximizing environmental benefits. PMID:25170307

  20. Transitioning organic synthesis from organic solvents to water. What's your E Factor?

    Science.gov (United States)

    Lipshutz, Bruce H; Ghorai, Subir

    2014-08-01

    Traditional organic chemistry, and organic synthesis in particular, relies heavily on organic solvents, as most reactions involve organic substrates and catalysts that tend to be water-insoluble. Unfortunately, organic solvents make up most of the organic waste created by the chemical enterprise, whether from academic, industrial, or governmental labs. One alternative to organic solvents follows the lead of Nature: water. To circumvent the solubility issues, newly engineered "designer" surfactants offer an opportunity to efficiently enable many of the commonly used transition metal-catalyzed and related reactions in organic synthesis to be run in water, and usually at ambient temperatures. This review focuses on recent progress in this area, where such amphiphiles spontaneously self-aggregate in water. The resulting micellar arrays serve as nanoreactors, obviating organic solvents as the reaction medium, while maximizing environmental benefits.

  1. Lipase catalyzed esterification of glycidol in organic solvents.

    Science.gov (United States)

    Martins, J F; Da Ponte, M N; Barreiros, S

    1993-08-05

    We studied the resolution of racemic glycidol through esterification with butyric acid catalyzed by porcine pancreatic lipase in organic media. A screening of seven solvents (log P values between 0.49 and 3.0, P being the n-octanol-water partition coefficient of the solvent) showed that neither log P nor the logarithm of the molar solubility of water in the solvent provides good correlations between enantioselectivity and the properties of the organic media. Chloroform was one of the best solvents as regards the enantiomeric purity (e. p.) of the ester produced. In this solvent, the optimum temperature for the reaction was determined to be 35 degrees C. The enzyme exhibited maximum activity at a water content of 13 +/- 2% (w/w). The enantiomeric purity obtained was 83 +/- 2% of (S)-glycidyl butyrate and did not depend on the alcohol concentration or the enzyme water content for values of these parameters up to 200 mM and 25% (w/w), respectively. The reaction was found to follow a BiBi mechanism.

  2. [Generic method for determination of volatile organic solvents in cosmetics].

    Science.gov (United States)

    Da, Jing; Huang, Xianglu; Wang, Gangli; Cao, Jin; Zhang, Qingsheng

    2014-11-01

    A generic screening, confirmation and determination method was established based on 36 commonly used volatile organic solvents in cosmetics by headspace gas chromatography- mass spectrometry (GC-MS). This method included a database for pilot screening and identifi- cation of those solvents and their quantitative method. Pilot screening database was composed by two sections, one was household section built by two columns with opposite polarities (col- umn VF-1301 ms and DB-5 ms) using retention index in different column systems as qualitative parameter, and the other was NIST MS search version 2.0. Meanwhile, the determination method of the 36 volatile solvents was developed with GC-MS. Cosmetic samples were dissolved in water and transferred to a headspace vial. After 30 min equilibration at 60 °C, the samples were analyzed by GC-MS equipped with a capillary chromatographic column VF-1301 ms. The external calibration was used for quantification. The limits of detection were from 0.01 to 3.3 μg/g, and the recoveries were from 60.77% to 126.6%. This study provided a generic method for pilot screening, identification, and quantitation of volatile organic solvents in cosmetics, and may solve the problem that different analytical methods need to be developed for different targeted compounds and pilot screening for potential candidate solvent residues.

  3. INFLUENCE OF ORGANIC SOLVENTS ON WATER DISSOCIATION IN BIPOLAR MEMBRANE

    Directory of Open Access Journals (Sweden)

    Sheldeshov N. V.

    2015-12-01

    Full Text Available The article discusses results of experimental research of the influence of aprotic and proton solvents on reaction rate of water molecules dissociation in the bipolar membrane MB-1 by the method of electrochemical impedance frequency spectrum. It was discovered, that addition of organic component in aqueous solutions results in significant influence on the parameters of water dissociation in a bipolar region of the membrane. The reason for this influence is the reduction of the mass fraction of water in solution and, consequently, in a bipolar region of the membrane, which itself reduces the rate of the dissociation reaction. Another reason for the influence of the organic solvent is its effect on the network of hydrogen bonds existing in water and aqueous solutions. Depending on the nature of organic solvent and its concentration, the network of hydrogen bonds may be strengthened, or destroyed, thus facilitating removal of the proton involved in the reactions between water molecules and catalytic centers in cation-exchange and anion-exchange layer of bipolar membrane, or retarding removal of proton. This leads respectively to speed up or slow down the rate of dissociation in the bipolar region of the membrane, as well as changing the constants of the dissociation reaction of water. Introduction of organic solvent in solutions, which are in the contact with bipolar membrane, is a convenient method of investigating the role of solution composition on the rate of proton transfer between water molecules and catalytic centers in the membranes

  4. Measurement of oxygen transfer from air into organic solvents

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias;

    2016-01-01

    For the first time, we demonstrate on-line oxygen measurements in non-aqueous media using a novel optical sensor. The sensor was used to measure oxygen concentration in various organic solvents including toluene, THF, isooctane, DMF, heptane and hexane (which have all been shown suitable for several biological...

  5. Peptide synthesis in neat organic solvents with novel thermostable proteases

    NARCIS (Netherlands)

    Toplak, Ana; Nuijens, Timo; Quaedflieg, Peter J L M; Wu, Bian; Janssen, Dick B

    2015-01-01

    Biocatalytic peptide synthesis will benefit from enzymes that are active at low water levels in organic solvent compositions that allow good substrate and product solubility. To explore the use of proteases from thermophiles for peptide synthesis under such conditions, putative protease genes of the

  6. Characteristics of peaks of inhalation exposure to organic solvents

    NARCIS (Netherlands)

    Preller, L.; Burstyn, I.; Pater, N. de; Kromhout, H.

    2004-01-01

    Objectives: To determine which exposure metrics are sufficient to characterize 'peak' inhalation exposure to organic solvents (OS) during spraying operations. Methods: Personal exposure measurements (n = 27; duration 5-159 min) were collected during application of paints, primers, resins and glues i

  7. SOLVENT EFFECTS ON THE HYDRATION OF CYCLOHEXENE CATALYZED BY A STRONG ACID ION-EXCHANGE RESIN .3. EFFECT OF SULFOLANE ON THE EQUILIBRIUM CONVERSION

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    1992-01-01

    The liquid-phase hydration of cyclohexene, a pseudo-first-order reversible reaction catalyzed by a strong acid ion-exchange resin, was investigated in solvent mixtures of water and sulfolane. Macroporous Amberlite XE 307 was used because of its superior catalytic activity. Chemical equilibrium conve

  8. Purification and characterization of organic solvent-stable lipase from organic solvent-tolerant Pseudomonas aeruginosa LST-03.

    Science.gov (United States)

    Ogino, H; Nakagawa, S; Shinya, K; Muto, T; Fujimura, N; Yasuda, M; Ishikawa, H

    2000-01-01

    An organic solvent-stable lipase (LST-03 lipase) secreted into the culture broth of the organic solvent-tolerant Pseudomonas aeruginosa LST-03 was purified by ion-exchange and hydrophobic interaction chromatography in the presence of 2-propanol. The purified enzyme was homogeneous as determined by SDS-PAGE. The molecular mass of the lipase was estimated to be 27.1 kDa by SDS-PAGE and 36 kDa by gel filtration. The optimum pH and temperature were 6.0 and 37 degrees C. LST-03 lipase was stable at pH 5-8 and below 40 degrees C. Its hydrolytic activity was highest against tricaproin (C6), methyl octanoate (C8), and coconut oil respectively among the triacylglycerols, fatty acid methyl esters, and natural oils investigated. The enzyme cleaved not only the 1,3-positioned ester bonds, but also the 2-positioned ester bond of triolein. It exhibited high levels of activity in the presence of n-decane, n-octane, DMSO, and DMF as well as in the absence of an organic solvent. In addition, LST-03 lipase was stabler in the presence of n-decane, ethyleneglycol, DMSO, n-octane, n-heptane, isooctane, and cyclohexane than in the absence of an organic solvent.

  9. Behavioral evaluation of workers exposed to mixtures of organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Maizlish, N.A.; Langolf, G.D.; Whitehead, L.W.; Fine, L.J.; Albers, J.W.; Goldberg, J.; Smith, P.

    1985-09-01

    Reports from Scandinavia have suggested behavioral impairment among long term workers exposed to solvents below regulatory standards. A cross sectional study of behavioral performance was conducted among printers and spray painters exposed to mixtures of organic solvents to replicate the Scandinavian studies and to examine dose-response relationships. Eligible subjects consisted of 640 hourly workers from four midwestern United States companies. Of these, 269 responded to requests to participate and 240 were selected for study based on restrictions for age, sex, education, and other potentially confounding variables. The subjects tested had been employed on average for six years. Each subject completed an occupational history, underwent a medical examination, and completed a battery of behavioural tests. These included the Fitts law psychomotor task, the Stroop color-word test, the Sternberg short term memory scanning test, the short term memory span test, and the continuous recognition memory test. Solvent exposure for each subject was defined as an exposed or non-exposed category based on a plant industrial hygiene walk-through and the concentration of solvents based on an analysis of full shift personal air samples by gas chromatography. The first definition was used to maintain consistency with Scandinavian studies, but the second was considered to be more accurate. The average full shift solvent concentration was 302 ppm for the printing plant workers and 6-13 ppm for the workers at other plants. Isopropanol and hexane were the major components, compared with toluene in Scandinavian studies.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-31

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

  11. [Pansclerotic porphyria cutanea tarda after chronic exposure to organic solvents].

    Science.gov (United States)

    Karamfilov, T; Buslau, M; Dürr, C; Weyers, W

    2003-05-01

    A 63 year old man developed generalized scleroderma with massive sclerotic areas, particularly in the abdominal region, four years after being diagnosed with porphyria cutanea tarda (PCT). He had almost daily exposure to organic solvents (benzene, trichlorethylene) for many years. The cutaneous fibrosis progressed dramatically leading to a pansclerosis, even though the uroporphyrin levels were borderline and the liver enzyme values were normal. Organic solvents are among those substances which can cause a cutaneous fibrosis. The unusually complicated clinical development in our patient was a combination of the two initial factors, the PCT and the long term exposure to organic solvents. The pansclerotic PCT was differentiated from a systemic sclerosis, a disabling pansclerotic morphea and a generalized morphea by means of histological examinations, the absence of a Raynaud phenomenon and the non-involvement of additional organs. Auto-antibodies typical for systemic sclerosis were negative. Using a medium dosage of UVA1 phototherapy and intensive physiotherapy, the progression of the skin disease was stopped and the sclerosis improved.

  12. Rational enhancement of enzyme performance in organic solvents. Final technical report, 1992--1996

    Energy Technology Data Exchange (ETDEWEB)

    Klibanov, A.M.

    1996-12-31

    This research focused on the following: the dependence of enzymatic activity of several model hydrolases in nonaqueous solvents; control of substrate selectivity of the protease subtilisin Carlsberg by the solvent; control of catalytic activity and enantioselectivity of this enzyme in organic solvents by immobilization support; lipase-catalyzed acylation of sugars in anhydrous hydrophobic media; the possibility of accelerating enzymatic processes in organic solvents by certain cosolvents; whether lipase catalysis in organic solvents can be enhanced by introducing interfaces in the in the reaction medium; the structure of proteins suspended in organic solvents; improving enzymatic enantioselectivity in organic solvents; analyzing the plunge in enzymatic activity upon replacing water with organic solvents; and the structural basis for the phenomenon of molecular memory of imprinted proteins in organic solvents.

  13. Alterations in cognitive and psychological functioning after organic solvent exposure

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, L.A.; Ryan, C.M.; Hodgson, M.J.; Robin, N. (Univ. of Pittsburgh School of Medicine, PA (USA))

    1990-05-01

    Exposure to organic solvents has been linked repeatedly to alterations in both personality and cognitive functioning. To assess the nature and extent of these changes more thoroughly, 32 workers with a history of exposure to mixtures of organic solvents and 32 age- and education-matched blue-collar workers with no history of exposure were assessed with a comprehensive battery of neuropsychological tests. Although both groups were comparable on measures of general intelligence, significant differences were found in virtually all other cognitive domains tested (Learning and Memory, Visuospatial, Attention and Mental Flexibility, Psychomotor Speed). In addition, Minnesota Multiphasic Personality Inventories of exposed workers indicated clinically significant levels of depression, anxiety, somatic concerns and disturbances in thinking. The reported psychological distress was unrelated to degree of cognitive deficit. Finally, several exposure-related variables were associated with poorer performance on tests of memory and visuospatial ability.

  14. A Peptide Amphiphile Organogelator of Polar Organic Solvents

    Science.gov (United States)

    Rouse, Charlotte K.; Martin, Adam D.; Easton, Christopher J.; Thordarson, Pall

    2017-01-01

    A peptide amphiphile is reported, that gelates a range of polar organic solvents including acetonitrile/water, N,N-dimethylformamide and acetone, in a process dictated by β-sheet interactions and facilitated by the presence of an alkyl chain. Similarities with previously reported peptide amphiphile hydrogelators indicate analogous underlying mechanisms of gelation and structure-property relationships, suggesting that peptide amphiphile organogel design may be predictably based on hydrogel precedents. PMID:28255169

  15. Niclosamide methanol solvate and niclosamide hydrate: structure, solvent inclusion mode and implications for properties.

    Science.gov (United States)

    Harriss, Bethany I; Wilson, Claire; Radosavljevic Evans, Ivana

    2014-08-01

    Structural studies have been carried out of two solid forms of niclosamide [5-chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamide, NCL], a widely used anthelmintic drug, namely niclosamide methanol monosolvate, C13H8Cl2N2O4·CH3OH or NCL·MeOH, and niclosamide monohydrate, denoted HA. The structure of the methanol solvate obtained from single-crystal X-ray diffraction is reported for the first time, elucidating the key host-guest hydrogen-bonding interactions which lead to solvate formation. The essentially planar NCL host molecules interact via π-stacking and pack in a herringbone-type arrangement, giving rise to channels along the crystallographic a axis in which the methanol guest molecules are located. The methanol and NCL molecules interact via short O-H...O hydrogen bonds. Laboratory powder X-ray diffraction (PXRD) measurements reveal that the initially phase-pure NCL·MeOH solvate readily transforms into NCL monohydrate within hours under ambient conditions. PXRD further suggests that the NCL monohydrate, HA, is isostructural with the NCL·MeOH solvate. This is consistent with the facile transformation of the methanol solvate into the hydrate when stored in air. The crystal packing and the topology of guest-molecule inclusion are compared with those of other NCL solvates for which the crystal structures are known, giving a consistent picture which correlates well with known experimentally observed desolvation properties.

  16. Personality and long term exposure to organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Lindstroem, K.; Martelin, T.

    1980-01-01

    Personality, especially emotional reactions of two solvent exposed groups and a nonexposed reference group were described by means of 20 formal, content and check-list type of Rorschach variables. Another objective of the study was to explore the suitability and psychological meaning of other types of Rorschach variables than those applied earlier in the field of behavioral toxicology. The factor analyses grouped the applied variables into factors of Productivity, Ego Strength, Control of Emotionality, Defensive Introversion and Aggressiveness. One solvent group, a patient groups (N.53), was characterized by a high number of Organic signs and a low Genetic Level, indicating possible psychoorganic deterioration. The other solvent group, styrene exposed but subjectively healthy (N.98), was characterized by few emotional reactions, low Anxiety and a low number of Neurotic Signs. the long duration of exposure of the solvent patient group (mean 10.2 +/- 8.7 years) was related to variables of the Productivity factor, a finding that indicates a possible better adjustment of those exposed for a longer time. The duration of exposure of the styrene exposed group (mean 4.9 +/- 3.2 years) revealed a very slight relation to personality variables, but the mean urinary mandelic acid concentration, indicating the level of styrene exposure, correlated with increased emotional reactions. For the most part definite causal conclusions could not be drawn because of the cross-sectional design of the study.

  17. Solubility of C60 and PCBM in Organic Solvents.

    Science.gov (United States)

    Wang, Chun I; Hua, Chi C

    2015-11-12

    The ability to correlate fullerene solubility with experimentally or computationally accessible parameters can significantly facilitate nanotechnology nowadays for a wide range of applications, while providing crucial insight into optimum design of future fullerene species. To date, there has been no single relationship that satisfactorily describes the existing data clearly manifesting the effects of solvent species, system temperature, and isomer. Using atomistic molecular dynamics simulations on two standard fullerene species, C60 and PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), in a representative series of organic solvent media (i.e., chloroform, toluene, chlorobenzene, 1,3-dichlorobenzene, and 1,2-dichlorobenzene), we show that a single time constant characterizing the dynamic stability of a tiny (angstrom-sized) solvation shell encompassing the fullerene particle can be utilized to effectively capture the known trends of fullerene solubility as reported in the literature. The underlying physics differs substantially between the two fullerene species, however. Although C60 was previously shown to be dictated by a diffusion-limited aggregation mechanism, the side-chain-substituted PCBM is demonstrated herein to proceed with an analogous reaction-limited aggregation with the "reaction rate" set by the fullerene rotational diffusivity in the medium. The present results suggest that dynamic quantities-in contrast to the more often employed, static ones-may provide an excellent means to characterize the complex (entropic and enthalpic) interplay between fullerene species and the solvent medium, shed light on the factors determining the solvent quality of a nanoparticle solution, and, in particular, offer a practical pathway to foreseeing optimum fullerene design and fullerene-solvent interactions.

  18. P300 brain potential among workers exposed to organic solvents

    Directory of Open Access Journals (Sweden)

    Bente E. Moen

    2009-10-01

    Full Text Available  SUMMARYThe P300 component of the auditory event-related brain potential was examined in a group of 11workers exposed to low levels of organic solvents in a paint factory and 11 unexposed controls beforeand after 3 weeks of summer vacation. The P300 latency time was found to be prolonged among theexposed workers compared to the reference group before the summer vacation, and to be significantlylonger before the vacation than after in the exposed group.The P300 component was also examined in a group of 85 seamen from chemical tankers, experiencingpeak exposures to organic solvents. They were compared to a reference group of unexposedseamen. Comparing these two groups, no difference was found in the P300 latency time. No relationshipbetween the P300 latency time and exposure was found in a multiple regression analysis, includingthe variables age, alcohol consumption, smoking and cerebral concussions.The study indicates the occurrence of an acute biological effect in the nervous system related toorganic solvent exposure, expressed by prolonged P300 latency time. This was found at very lowexposure levels and should be studied further.

  19. Chemical modification of alginates in organic solvent systems.

    Science.gov (United States)

    Pawar, Siddhesh N; Edgar, Kevin J

    2011-11-14

    Alginates are (1→4)-linked linear copolysaccharides composed of β-D-mannuronic acid (M) and its C-5 epimer, α-l-guluronic acid (G). Several strategies to synthesize organically modified alginate derivatives have been reported, but almost all chemistries are performed in either aqueous or aqueous-organic media. The ability to react alginates homogeneously in organic solvents would open up access to a wide range of new chemistries and derivatives. However, past attempts have been restricted by the absence of methods for alginate dissolution in organic media. We therefore report a strategy to dissolve tetrabutylammonium (TBA) salts of alginic acid in polar aprotic solvents containing tetrabutylammonium fluoride (TBAF). Acylation of TBA-alginate was performed under homogeneous conditions, such that both M and G residues were acetylated up to a total degree of substitution (DS) ≈1.0. Performing the same reaction under heterogeneous conditions resulted in selective acylation of M residues. Regioselectivity in the acylated alginate products was studied, and degradation under basic reaction conditions was probed.

  20. Enzyme catalysis in organic solvents: influence of water content, solvent composition and temperature on Candida rugosa lipase catalyzed transesterification.

    Science.gov (United States)

    Herbst, Daniela; Peper, Stephanie; Niemeyer, Bernd

    2012-12-31

    In the present study the influence of water content, solvent composition and reaction temperature on the transesterification of 1-phenylpropan-2-ol catalyzed by Candida rugosa lipase was examined. Reactions were carried out in different mixtures of hexane and tetrahydrofurane. The studies showed that an increasing water content of the organic solvent results in an increasing enzyme activity and a decreasing enantiomeric excess. Furthermore, a significant influence of the solvent hydrophilicity both on the enzyme activity and on the enantiomeric excess was found. An increase in solvent hydrophilicity leads to a decrease of enzyme activity and an increase of the enantiomeric excess. This indicates that the enzyme becomes more selective with decreasing flexibility. Similar effects were found by variation of the reaction temperature. Taken together, the decrease in conversion and the increase in selectivity with increasing solvent hydrophilicity are induced by the different water contents on the enzyme surface and not by the solvent itself.

  1. Effect of Organic Solvents on Microalgae Growth, Metabolism and Industrial Bioproduct Extraction: A Review

    Science.gov (United States)

    Miazek, Krystian; Sulc, Radek; Jirout, Tomas; Aguedo, Mario; Goffin, Dorothee

    2017-01-01

    In this review, the effect of organic solvents on microalgae cultures from molecular to industrial scale is presented. Traditional organic solvents and solvents of new generation-ionic liquids (ILs), are considered. Alterations in microalgal cell metabolism and synthesis of target products (pigments, proteins, lipids), as a result of exposure to organic solvents, are summarized. Applications of organic solvents as a carbon source for microalgal growth and production of target molecules are discussed. Possible implementation of various industrial effluents containing organic solvents into microalgal cultivation media, is evaluated. The effect of organic solvents on extraction of target compounds from microalgae is also considered. Techniques for lipid and carotenoid extraction from viable microalgal biomass (milking methods) and dead microalgal biomass (classical methods) are depicted. Moreover, the economic survey of lipid and carotenoid extraction from microalgae biomass, by means of different techniques and solvents, is conducted. PMID:28677659

  2. Mixed organic solvents induce renal injury in rats.

    Directory of Open Access Journals (Sweden)

    Weisong Qin

    Full Text Available To investigate the injury effects of organic solvents on kidney, an animal model of Sprague-Dawley (SD rats treated with mixed organic solvents via inhalation was generated and characterized. The mixed organic solvents consisted of gasoline, dimethylbenzene and formaldehyde (GDF in the ratio of 2:2:1, and were used at 12,000 PPM to treat the rats twice a day, each for 3 hours. Proteinuria appeared in the rats after exposure for 5-6 weeks. The incidences of proteinuria in male and female rats after exposure for 12 weeks were 43.8% (7/16 and 25% (4/16, respectively. Urinary N-Acetyl-β-(D-Glucosaminidase (NAG activity was increased significantly after exposure for 4 weeks. Histological examination revealed remarkable injuries in the proximal renal tubules, including tubular epithelial cell detachment, cloud swelling and vacuole formation in the proximal tubular cells, as well as proliferation of parietal epithelium and tubular reflux in glomeruli. Ultrastructural examination found that brush border and cytoplasm of tubular epithelial cell were dropped, that tubular epithelial cells were partially disintegrated, and that the mitochondria of tubular epithelial cells were degenerated and lost. In addition to tubular lesions, glomerular damages were also observed, including segmental foot process fusion and loss of foot process covering on glomerular basement membrane (GBM. Immunofluorescence staining indicated that the expression of nephrin and podocin were both decreased after exposure of GDF. In contrast, increased expression of desmin, a marker of podocyte injury, was found in some areas of a glomerulus. TUNEL staining showed that GDF induced apoptosis in tubular cells and glomerular cells. These studies demonstrate that GDF can induce both severe proximal tubular damage and podocyte injury in rats, and the tubular lesions appear earlier than that of glomeruli.

  3. Interaction of protonated merocyanine dyes with amines in organic solvents

    Science.gov (United States)

    Ribeiro, Eduardo Alberton; Sidooski, Thiago; Nandi, Leandro Guarezi; Machado, Vanderlei Gageiro

    2011-10-01

    2,6-Diphenyl-4-(2,4,6-triphenylpyridinium-1-yl)phenolate ( 1a) and 4-[(1-methyl-4(1 H)-pyridinylidene)-ethylidene]-2,5-cyclohexadien-1-one ( 2a) were protonated in organic solvents (dichloromethane, acetonitrile, and DMSO) to form 1b and 2b, respectively. The appearance of the solvatochromic bands of 1a and 2a was studied UV-vis spectrophotometrically by deprotonation of 1b and 2b in solution in the presence of the following amines: aniline (AN), N-methylaniline (NMAN), N, N-dimethylaniline (NDAN), n-butylamine (BA), diethylamine (DEA), and triethylamine (TEA). Titrations of 1b and 2b with the amines were carried out and the binding constants were determined from the titration curves in each solvent, using a mathematical model adapted from the literature which considers the simultaneous participation of two dye: amine stoichiometries, 1:1 and 1:2. The data obtained showed the following base order for the two compounds in DMSO: BA > DEA > TEA, while aromatic amines did not cause any effect. In dichloromethane, the following base order for 1b was verified: TEA > DEA > BA ≫NDAN, while for 2b the order was: TEA > DEA > BA, suggesting that 1b is more acidic than 2b. The data in acetonitrile indicated for 1b and 2b the following order for the amines: DEA > TEA > BA. The diversity of the experimental data were explained based on a model that considers the level of interaction of the protonated dyes with the amines to be dependent on three aspects: (a) the basicity of the amine, which varies according to their molecular structure and the solvent in which it is dissolved, (b) the molecular structure of the dye, and (c) the solvent used to study the system.

  4. Nitration of Wood Cellulose in HNO3/Organic Solvent Medium

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A steam explosion pretreatment at various severities was applied to pure wood cellulose; the influences of steam pretreatment on the morphological structure, the hydrophilic property and viscosity-average molecular weight of cellulose were evaluated. The nitration of steam-exploded cellulose was carried out in the nitrating agent medium (HNO3/organic solvent). The performance indexes of nitrocellulose, prepared from original and steam exploded samples, were determined by using the polarized optical microscope. The results show that after pretreatment the reactivity of the three hydroxyl groups in anhydroglucose unit of cellulose is improved, and the nitrogen content and the uniformity of NC from steam exploded cellulose observably increas.

  5. [Effect of organic solvents on the central nervous system].

    Science.gov (United States)

    Langauer-Lewowicka, H; Witecki, K; Braszczyńska, Z; Wocka-Marek, T; Byczkowska, Z

    1983-01-01

    Psychological tests and EEG investigations were applied for detecting early signs of neurotoxicity of organic solvents present in glues used in the production of shoes (extraction benzin, toluene and n-hexane). In 5% of the obtained samples the permissible benzin concentration was exceeded, and in 10% of samples this permissible concentration of toluene was exceeded. Psychological testing was done in 100 subjects. The intelligence level was at the lower normal range. Organic cortical changes were demonstrated in 35 cases, and borderline pathological changes in 28 cases. The test of L. Bender suggested damage to the occipital cortex in 31, and the Graham-Kendal test demonstrated abnormalities in 13 cases. EEG was done in 56 subjects in this group and in another 9 subjects with a high concentration of toluene metabolite. In 75.4% of subjects the EEG findings were classified as normal, within normal limits or borderline normal. Abnormal EEG tracings were found in 24.0%. Diffuse, slight or moderately intense abnormalities were present in 7 cases, focal abnormalities in 4 and seizure activity in 7. Most subjects with abnormal EEG findings worked under conditions of excessive exposure, with the summarized exposure index exceeding the acceptable one. No correlation was demonstrated between cortical pathological changes and the degree of occupational exposure and the type of EEG tracings. The authors suggest that organic occipital cortical changes may be regarded as an early phase of organic brain damage syndrome and disturbances of cerebral bioelectric activity as a sign of individual biological response to chronic action of organic solvents on the organism.

  6. Effect of organic solvents on the central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Langauer-Lewowicka, H.; Witecki, K.; Braszczynska, Z.; Wocka-Marek, T.; Byczkowska, Z.

    Psychological tests and EEG investigations were applied for detecting early signs of neurotoxicity of organic solvents present in glues used in the production of shoes (extraction benzin, toluene and n-hexane). In 5% of the obtained samples the permissible benzin concentration was exceeded, and in 10% of samples this permissible concentration of toluene was exceeded. Psychological testing was done in 100 subjects. The intelligence level was at the lower normal range. Organic cortical changes were demonstrated in 35 cases, and borderline pathological changes in 28 cases. The test of L. Bender suggested damage to the occipital cortex in 31, and the Graham-Kendal test demonstrated abnormalities in 13 cases. EEG was done in 56 subjects in this group and in another 9 subjects with a high concentration of toluene metabolite. In 75.4% of subjects the EEG findings were classified as normal, within normal limits or borderline normal. Abnormal EEG tracings were found in 24.0%. Diffuse, slight or moderately intense abnormalities were present in 7 cases, focal abnormalities in 4 and seizure activity in 7. Most subjects with abnormal EEG findings worked under conditions of excessive exposure, with the summarized exposure index exceeding the acceptable one. No correlation was demonstrated between cortical pathological changes and the degree of occupational exposure and the type of EEG tracings. The authors suggest that organic occipital cortical changes may be regarded as an early phase of organic brain damage syndrome and disturbances of cerebral bioelectric activity as a sign of individual biological response to chronic action of organic solvents on the organism.

  7. High exposures to organic solvents among graffiti removers.

    Science.gov (United States)

    Anundi, H; Lind, M L; Friis, L; Itkes, N; Langworth, S; Edling, C

    1993-01-01

    The exposure to organic solvents among 12 graffiti removers was studied. Health effects were also assessed by structured interview and a symptom questionnaire. Blood and urine samples were collected at the end of the day of air sampling. The concentrations of dichloromethane, glycol ethers, trimethylbenzenes and N-methyl-2-pyrrolidinone in the breathing zone of each worker were measured during one working day. The 8-h time-weighted average exposure to dichloromethane ranged from 18 to 1200 mg/m3. The Swedish Permissible Exposure Limit value for dichloromethane is 120 mg/m3. The air concentrations of glycol ethers, trimethylbenzenes and N-methyl-2-pyrrolidinone were low or not detectable. No exposure-related deviations in the serum concentrations of creatinine, aspartate transaminase, alanine transaminase, gamma-glutamyl transpeptidase or hyaluronan or the urine concentrations of alpha 1-microglobulin, beta 2-microglobulin or N-acetyl-beta-glucosaminidase were found. Irritative symptoms of the eyes and upper respiratory tract were more prevalent than in the general population. This study demonstrates that old knowledge about work hazards is not automatically transferred to new professions. Another aspect is that the public is also exposed as the job is performed during daytime in underground stations. At least for short periods, bystanders may be exposed to high concentrations of organic solvent vapours. People with predisposing conditions, e.g. asthmatics, may risk adverse reactions.

  8. Major neurological disease and occupational exposure to organic solvents.

    Science.gov (United States)

    Seaton, A; Jellinek, E H; Kennedy, P

    1992-09-01

    Five patients are described who presented with major organic brain disease affecting one or more of pyramidal and extrapyramidal tracts, cerebellum, and higher cortical functions. All had a history of 10 years or more of regular occupational exposure to solvents in confined spaces, three in painting inside ships and the others in weapons maintenance and printing. All had been regularly exposed to high air vapour peaks as well as to skin contamination. Four showed some evidence of improvement after the exposure ceased. None was initially suspected of having a toxic encephalopathy by the consultant to whom he was referred. The spectrum of neurological disease presented by these men mirrors closely that described in solvent abusers. All were forced by illness to retire from their work, a circumstance which might have in the past have led to such conditions being missed in cross-sectional studies, which in general have not shown evidence of major disease. We suggest that when such disease occurs nowadays, its cause is usually not suspected. Further epidemiological study of the problem is necessary.

  9. Photochemical reactions of brominated diphenylethers in organic solvents and adsorbed on silicon dioxide in aqueous suspension

    Energy Technology Data Exchange (ETDEWEB)

    Palm, W.U.; Kopetzky, R.; Sossinka, W.; Ruck, W. [Univ. of Lueneburg, Environmental Chemistry, Lueneburg (Germany); Zetzsch, C. [Univ. of Bayreuth, Atmos. Chem. Research, Bayreuth, and Fraunhofer-Inst. of Toxicology and Experimental Medicine, Hannover (Germany)

    2004-09-15

    Polybrominated diphenylethers (BDEs) are in use as flame retardants worldwide and are found as xenobiotics in environmental samples. Photolysis by sunlight, one of the potential abiotic degradation pathways, is found to be rapid in laboratory experiments, especially for deca-BDE, the most prominent BDE as compared to commercial penta- and octa-BDEs. Due to the extremely low water solubility of BDEs, these experiments were mostly performed in organic solvents so far, and a few in environmental matrices (sand and soil) and on dry and hydrated quartz glass. However, detailed UV absorption spectra of deca-BDE and debrominated BDEs in the relevant wavelength range above 300 nm have become available only recently, besides the UV maxima of a number of synthesized congeners at shorter wavelengths and an exploratory study from our laboratory. Other important parameters to assess the abiotic degradation in the environment, such as OH-rate constants and photolytic quantum yields of BDEs are not available. Furthermore, analysis of BDEs was mostly performed by GC-MS, and the capability of HPLC with a diode array detector (DAD) has not yet been exploited. This study presents kinetic results on the photolysis of BDEs in tetrahydrofuran (THF) with detailed photolytic pathways for a tetra-BDE (2,2'4,4'-BDE), a hexa-BDE (2,2'4,4',5,5'-BDE) and deca-BDE. Employing HPLC with a diode array detector (DAD) as analytical tool, quantum yields of BDEs with N{sub Br} = 1-10 are determined. Furthermore, the formation of brominated dibenzofurans (BDFs) was investigated. Since the environmental relevance of photolysis experiments in organic solvents is questionable, first results on photolysis of deca-BDE adsorbed on silicon dioxide particles, suspended in water, are presented.

  10. Peptide synthesis in neat organic solvents with novel thermostable proteases.

    Science.gov (United States)

    Toplak, Ana; Nuijens, Timo; Quaedflieg, Peter J L M; Wu, Bian; Janssen, Dick B

    2015-06-01

    Biocatalytic peptide synthesis will benefit from enzymes that are active at low water levels in organic solvent compositions that allow good substrate and product solubility. To explore the use of proteases from thermophiles for peptide synthesis under such conditions, putative protease genes of the subtilase class were cloned from Thermus aquaticus and Deinococcus geothermalis and expressed in Escherichia coli. The purified enzymes were highly thermostable and catalyzed efficient peptide bond synthesis at 80°C and 60°C in neat acetonitrile with excellent conversion (>90%). The enzymes tolerated high levels of N,N-dimethylformamide (DMF) as a cosolvent (40-50% v/v), which improved substrate solubility and gave good conversion in 5+3 peptide condensation reactions. The results suggest that proteases from thermophiles can be used for peptide synthesis under harsh reaction conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    YOUNGJUNE ePARK

    2015-10-01

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

  12. Renal effects of chronic exposure to organic solvents. A clinical controlled trial

    DEFF Research Database (Denmark)

    Krusell, Lars Romer; Nielsen, H K; Bælum, Jesper

    1985-01-01

    Chronic effects of organic solvents on renal function were measured by creatinine clearances and urinary excretion rates of beta 2-microglobulin and albumin. Forty-three male printing trade workers occupationally exposed to different organic solvents for 9-25 years were compared with 43 age....... This investigation did not reveal any adverse renal effects of moderate chronic exposure to organic solvents in a group of active trade workers....

  13. XAFS study of bioactive Cu(II) complexes of 7-hydroxycoumarin derivatives in organic solvents

    Science.gov (United States)

    Klepka, M. T.; Wolska, A.; Drzewiecka-Antonik, A.; Rejmak, P.; Hatada, K.; Aquilanti, G.

    2017-04-01

    We characterize the structure of two Cu(II) complexes of 7-hydroxycoumarins in organic solvents. The solvents are, dimethyl sulfoxide and dimethylformamide. X-ray absorption spectroscopy together with density functional theory calculations are employed to identify the structural changes induced by the two solvents in comparison to the solid form of complexes. We show that the structure of the Cu(II) complexes is modified depending on the solvent and we propose the geometry of the complexes molecule.

  14. Effect of regular organic solvents on cytochrome P450-mediated metabolic activities in rat liver microsomes.

    Science.gov (United States)

    Li, Dan; Han, Yonglong; Meng, Xiangle; Sun, Xipeng; Yu, Qi; Li, Yan; Wan, Lili; Huo, Yan; Guo, Cheng

    2010-11-01

    The effects of regular organic solvents on the metabolic activities of various human cytochromes P450 (P450s) have been reported. However, very little is known about their influence on metabolic activities mediated by P450s in the rat liver microsomes (RLM). The purpose of this study was to investigate the effects of organic solvents such as methanol, acetonitrile, dimethyl sulfoxide (DMSO), acetone, and ethanol on CYP1A, CYP2C, CYP2D, CYP2E, and CYP3A-mediated metabolism using RLM. The results showed that the activities of most rat P450 enzymes appeared to be organic solvent-dependent, and the metabolism of the tested probes were remarkably reduced when the concentration of organic solvents was up to 5% v/v, whereas most organic solvents demonstrated no significant interference when the concentration was below 1%, with the exception of DMSO. In addition, organic solvents exhibited different inhibitory effects, for example, CYP2D and CYP2E showed a significant reduction of activities at lower concentrations of organic solvents. Hence, this phenomenon should be taken into consideration when designing in vitro metabolism studies of new chemical entities. Therefore, we recommend acetonitrile as the most suitable solvent for RLM incubations, and the content of organic solvent should be kept lower than 1% v/v.

  15. Lipase catalyzed esterification of glycidol in nonaqueous solvents: solvent effects on enzymatic activity.

    Science.gov (United States)

    Martins, J F; de Sampaio, T C; de Carvalho, I B; Barreiros, S

    1994-06-05

    We studied the effect of organic solvents on the kinetics of porcine pancreatic lipase (pp) for the resolution of racemic glycidol through esterification with butyric acid. We quantified ppl hydration by measuring water sorption isotherms for the enzyme in the solvents/mixtures tested. The determination of initial rates as a function of enzyme hydration revealed that the enzyme exhibits maximum apparent activity in the solvents/mixtures at the same water content (9% to 11% w/w) within the associated experimental error. The maximum initial rates are different in all the media and correlate well with the logarithm of the molar solubility of water in the media, higher initial rates being observed in the solvents/mixtures with lower water solubilities. The data for the mixtures indicate that ppl apparent activity responds to bulk property of the solvent. Measurements of enzyme particle sizes in five of the solvents, as function of enzyme hydration, revealed that mean particle sizes increased with enzyme hydration in all the solvents, differences between solvents being more pronounced at enzyme hydration levels close to 10%. At this hydration level, solvents having a higher water content lead to lower reaction rates; these are the solvents where the mean enzyme particle sizes are greater. Calculation of the observable modulus indicates there are no internal diffusion limitations. The observed correlation between changes in initial rates and changes in external surface area of the enzyme particles suggests that interfacial activation of ppl is only effective at the external surface of the particles. Data obtained for the mixtures indicate that ppl enantioselectivity depends on specific solvent-enzyme interactions. We make reference to ppl hydration and activity in supercritical carbon dioxide.

  16. Solvents in Organic Synthesis: Replacement and Multi-step Reaction Systems

    DEFF Research Database (Denmark)

    Gani, Rafiqul; Gómez, Paola Arenas; Folic, Milica

    2008-01-01

    with the principles of green chemistry, highlight the need to minimize and optimize the use of organic solvents as much as possible. One important step in optimizing organic solvent use is the identification of suitable ‘greener' solvents that can help to minimize the environmental, health and safety concerns during...... design and commercial manufacture of chemical products. A method for selecting appropriate ‘greener' solvents for the promotion of a class of organic reactions has been previously developed by Gani et al. This method employs estimates of thermodynamic properties to generate a knowledge base of reaction...

  17. Modeling structure and flexibility of Candida antarctica lipase B in organic solvents

    Directory of Open Access Journals (Sweden)

    Pleiss Jürgen

    2008-02-01

    Full Text Available Abstract Background The structure and flexibility of Candida antarctica lipase B in water and five different organic solvent models was investigated using multiple molecular dynamics simulations to describe the effect of solvents on structure and dynamics. Interactions of the solvents with the protein and the distribution of water molecules at the protein surface were examined. Results The simulated structure was independent of the solvent, and had a low deviation from the crystal structure. However, the hydrophilic surface of CALB in non-polar solvents decreased by 10% in comparison to water, while the hydrophobic surface is slightly increased by 1%. There is a large influence on the flexibility depending on the dielectric constant of the solvent, with a high flexibility in water and a low flexibility in organic solvents. With decreasing dielectric constant, the number of surface bound water molecules significantly increased and a spanning water network with an increasing size was formed. Conclusion The reduced flexibility of Candida antarctica lipase B in organic solvents is caused by a spanning water network resulting from less mobile and slowly exchanging water molecules at the protein-surface. The reduced flexibility of Candida antarctica lipase B in organic solvent is not only caused by the interactions between solvent-protein, but mainly by the formation of a spanning water network.

  18. Renal effects of chronic exposure to organic solvents. A clinical controlled trial

    DEFF Research Database (Denmark)

    Krusell, Lars Romer; Nielsen, H K; Bælum, Jesper;

    1985-01-01

    Chronic effects of organic solvents on renal function were measured by creatinine clearances and urinary excretion rates of beta 2-microglobulin and albumin. Forty-three male printing trade workers occupationally exposed to different organic solvents for 9-25 years were compared with 43 age-match...

  19. Paternal Organic Solvent Exposure and Adverse Pregnancy Outcomes: A Meta-Analysis

    NARCIS (Netherlands)

    Logman, J.F.S.; Vries, L.E. de; Hemels, M.E.H.; Khattak, S.; Einarson, T.R.

    2005-01-01

    Background: Organic solvents are widely used, but conflicting reports exist concerning paternal exposure and adverse pregnancy outcomes. We conducted a meta-analysis to assess the risks of spontaneous abortions (SAs) and major malformations (MMs) after paternal exposure to organic solvents. Methods:

  20. 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...... on oxidative phosphorylation in mitochondria should therefore include the use of relevant concentrations of the organic solvent in order to validate the contribution....

  1. Enzymatic Synthesis of Esculin Ester in Ionic Liquids Buffered with Organic Solvents

    DEFF Research Database (Denmark)

    Hu, Yifan; Guo, Zheng; Lue, Bena-Marie

    2009-01-01

    The enzymatic esterification of esculin catalyzed by Candida antarctica lipase B (Novozym 435) was carried out in ionic liquid (IL)-organic solvent mixed systems in comparison with individual systems. The reaction behaviors in IL-organic solvents were systemically evaluated using acetone as a mod...

  2. FT-IR spectroscopy and DFT calculation study on the solvent effects of benzaldehyde in organic solvents.

    Science.gov (United States)

    Li, Yi; Zhang, Hui; Liu, Qing

    2012-02-01

    FT-IR spectra of benzaldehyde in 11 different organic solvents were recorded and analyzed. The density functional theory (DFT) B3LYP/6-31G* method was chosen to calculate the infrared spectrum of benzaldehyde in gaseous state. The electrostatic effects of different solvents in benzaldehyde solutions were calculated using DFT with the self-consistent isodensity polarizable continuum model (SCI-PCM). Two remarkable carbonyl (C=O) peaks of benzaldehyde were observed by FT-IR in alcohol solvents, which were caused by different hydrogen bond species and explained by ab initio calculation. The results showed that the combination of SCI-PCM model and ab initio calculation could give excellent agreements with FT-IR spectra of title compound in solutions.

  3. Organic solvent exposure and depressive symptoms among licensed pesticide applicators in the Agricultural Health Study.

    Science.gov (United States)

    Siegel, Miriam; Starks, Sarah E; Sanderson, Wayne T; Kamel, Freya; Hoppin, Jane A; Gerr, Fred

    2017-07-12

    Although organic solvents are often used in agricultural operations, neurotoxic effects of solvent exposure have not been extensively studied among farmers. The current analysis examined associations between questionnaire-based metrics of organic solvent exposure and depressive symptoms among farmers. Results from 692 male Agricultural Health Study participants were analyzed. Solvent type and exposure duration were assessed by questionnaire. An "ever-use" variable and years of use categories were constructed for exposure to gasoline, paint/lacquer thinner, petroleum distillates, and any solvent. Depressive symptoms were ascertained with the Center for Epidemiologic Studies Depression Scale (CES-D); scores were analyzed separately as continuous (0-60) and dichotomous (exposure and CES-D score. Forty-one percent of the sample reported some solvent exposure. The mean CES-D score was 6.5 (SD 6.4; median 5; range 0-44); 92% of the sample had a score below 16. After adjusting for covariates, statistically significant associations were observed between ever-use of any solvent, long duration of any solvent exposure, ever-use of gasoline, ever-use of petroleum distillates, and short duration of petroleum distillate exposure and continuous CES-D score (p exposure and the dichotomized CES-D variable. Solvent exposures were associated with depressive symptoms among farmers. Efforts to limit exposure to organic solvents may reduce the risk of depressive symptoms among farmers.

  4. Solvents, Ethanol, Car Crashes and Tolerance: How Risky is Inhalation of Organic Solvents?

    Science.gov (United States)

    A research program in the National Health and Environmental Effects Research Laboratory of the U.S. EPA has led to some surprising considerations regarding the potential hazard of exposure to low concentrations of solvent vapors. This program involved conducting experiments to ch...

  5. High-Pressure Solvent Vapor Annealing with a Benign Solvent To Rapidly Enhance the Performance of Organic Photovoltaics.

    Science.gov (United States)

    Jung, Buyoung; Kim, Kangmin; Eom, Yoomin; Kim, Woochul

    2015-06-24

    A high-pressure solvent vapor annealing (HPSVA) treatment is suggested as an annealing process to rapidly achieve high-performance organic photovoltaics (OPVs); this process can be compatible with roll-to-roll processing methods and uses a benign solvent: acetone. Solvent vapor annealing can produce an advantageous vertical distribution in the active layer; however, conventional solvent vapor annealing is also time-consuming. To shorten the annealing time, high-pressure solvent vapor is exposed on the active layer of OPVs. Acetone is a nonsolvent for poly(3-hexylthiophene-2,5-diyl) (P3HT), but it can dissolve small amounts of 1-(3-methoxycarbonyl)-propyl-1,1-phenyl-(6,6)C61 (PCBM). Acetone vapor molecules can penetrate into the active layer under high vapor pressure conditions to alter the morphology. HPSVA induces a PCBM-rich phase near the cathode and facilitates the transport of free charge carriers to the electrode. Although P3HT is not soluble in acetone, locally rearranged P3HT crystallites are generated. The performance of OPV films was enhanced after HPSVA; the film treated at 30 kPa for 10 s showed optimum performance. Additionally, this HPSVA method could be adapted for mass production because the temporary exposure of films to high-pressure acetone vapor in ambient conditions also improved performance.

  6. Multi-media regulatory requirements for an organic solvent wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Pintenich, J.L.; Bazydola, M.T. [Eckenfelder Inc., Nashville, TN (United States)

    1997-12-31

    The increasingly complex sets of environmental statutes and regulations in the United States have and will continue to present the designers and operators of aqueous waste treatment systems with significant challenges to meet regulatory performance standards for all media receiving an emission or discharge of some type. This paper summarizes the rigorous evaluations of multi-media environmental regulatory requirements for air emissions, water discharges, and treatment sludge which established that a groundwater treatment system at a National Priorities List (NPL) Superfund site could be designed and operated in a cost-effective manner. Pilot-scale treatability studies were used to develop the process design and demonstrate the attainment of extremely stringent water-quality based effluent limitations for this organic solvent wastewater. Dispersion modeling using Industrial Source Complex Long Term (ISCLT) demonstrated that predicted ground level concentrations of vinyl chloride and other hazardous air pollutants (HAPs) would be below state air toxics values. Emission rates were demonstrated to be below the relevant National Emission Standard for Hazardous Air Pollutants (NESHAPs) as well as state emissions rate guidelines. Candidate emission control technologies were identified and evaluated on a life-cycle cost basis in accordance with the QAQPS Control Cost Manual published by USEPA to assess the feasibility of control. Adsorption with granular activated carbon, adsorption with a proprietary adsorbent, and catalytic oxidation were conceptualized for possible use at the site. The project received a discharge permit approval for the treated wastewater as well as a permit exemption for the air emission. During the first six months after startup, the treatment system was demonstrated to achieve the regulatory performance requirements.

  7. Fast molecular beacon hybridization in organic solvents with improved target specificity.

    Science.gov (United States)

    Dave, Neeshma; Liu, Juewen

    2010-12-02

    DNA hybridization is of tremendous importance in biology, bionanotechnology, and biophysics. Molecular beacons are engineered DNA hairpins with a fluorophore and a quencher labeled on each of the two ends. A target DNA can open the hairpin to give an increased fluorescence signal. To date, the majority of molecular beacon detections have been performed only in aqueous buffers. We describe herein DNA detection in nine different organic solvents, methanol, ethanol, isopropanol, acetonitrile, formamide, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethylene glycol, and glycerol, varying each up to 75% (v/v). In comparison with detection in water, the detection in organic solvents showed several important features. First, the molecular beacon hybridizes to its target DNA in the presence of all nine solvents up to a certain percentage. Second, the rate of this hybridization was significantly faster in most organic solvents compared with water. For example, in 56% ethanol, the beacon showed a 70-fold rate enhancement. Third, the ability of the molecular beacon to discriminate single-base mismatch is still maintained. Lastly, the DNA melting temperature in the organic solvents showed a solvent concentration-dependent decrease. This study suggests that molecular beacons can be used for applications where organic solvents must be involved or organic solvents can be intentionally added to improve the molecular beacon performance.

  8. Fetotoxic effects of exposure to the vapor of organic solvents from a synthetic adhesive in mice

    Energy Technology Data Exchange (ETDEWEB)

    Tachi, N.; Shimotori, S.; Naruse, N.; Itani, T.; Aoyama, M. (Nagoya City Univ. Medical School (Japan)); Fujise, H.; Sonoki, S. (Azabu Univ., Kanagawa (Japan))

    1994-09-01

    Synthetic adhesives are widely used in various industries as well as at home. Adhesives usually contain several organic solvents which easily vaporize. Exposure can cause aplastic anemia and polyneuropathy in adults. Chronic glue sniffing results in aplastic anemia, polyneuropathy, and muscular atrophy. Inhalation of the solvent contained in adhesives, such as n-hexane, toluene, xylene, and benzene by pregnant animals can decrease the number of live fetuses and retard fetal growth. In humans, the risk of spontaneous abortion is increased in workers exposed to organic solvents. However, information is still limited about the effects of exposure to organic solvents vaporized from adhesives on fetuses. In the present study, female mice were exposed throughout pregnancy to organic solvents vaporized from an adhesive to clarify the effects of the inhalation on progeny. 19 refs., 1 fig., 4 tabs.

  9. Water-enhanced solubility of carboxylic acids in organic solvents and its applications to extraction processes

    Energy Technology Data Exchange (ETDEWEB)

    Starr, J.N.; King, C.J.

    1991-11-01

    The solubilities of carboxylic acids in certain organic solvents increase remarkably with an increasing amount of water in the organic phase. This phenomenon leads to a novel extract regeneration process in which the co-extracted water is selectively removed from an extract, and the carboxylic acid precipitates. This approach is potentially advantageous compared to other regeneration processes because it removes a minor component of the extract in order to achieve a large recovery of acid from the extract. Carboxylic acids of interest include adipic acid, fumaric acid, and succinic acid because of their low to moderate solubilities in organic solvents. Solvents were screened for an increase in acid solubility with increased water concentration in the organic phase. Most Lewis-base solvents were found to exhibit this increased solubility phenomena. Solvents that have a carbonyl functional group showed a very large increase in acid solubility. 71 refs., 52 figs., 38 tabs.

  10. The effect of solvent-conditioning on soil organic matter sorption affinity for diuron and phenanthrene.

    Science.gov (United States)

    Ahangar, Ahmad Gholamalizadeh; Smernik, Ronald J; Kookana, Rai S; Chittleborough, David J

    2009-08-01

    The effect of solvent-conditioning on the sorption of diuron and phenanthrene was investigated. The organic carbon-normalized sorption coefficients (K(OC)) for diuron and phenanthrene (determined from single initial concentrations of 0.8mgL(-1) and 1.5mgL(-1), respectively) were consistently higher following solvent-conditioning of a whole soil with five organic solvents (acetonitrile, acetone, methanol, chloroform and dichloromethane). The relative increase in K(OC) was inversely related to the polarity of the conditioning solvent (i.e. greater increases in K(OC) were observed for the least polar solvents: chloroform and dichloromethane). The effect of solvent-conditioning on the sorption properties of the same soil that had been lipid-extracted using accelerated solvent extraction (ASE) was also investigated. Since lipid extraction involves treatment with a non-polar solvent (95:5 dichloromethane:methanol) one may have expected no further increase in K(OC) on solvent-conditioning. On the contrary, the lipid-extracted soil exhibited very similar increases in K(OC) as the whole soil. This demonstrated that lipid removal and solvent-conditioning, which both increased K(OC) for this soil, are quite separate phenomena.

  11. Assessment of Relationship between Spontaneous Abortion and Occupational Exposure to Organic Solvents

    Directory of Open Access Journals (Sweden)

    S Mohammadi

    2011-04-01

    Full Text Available Introduction & Objective: Nowadays, some studies indicate the adverse effects of exposure to chemicals, especially organic solvents on the reproductive system of females. This study aimed to assess the relationship between spontaneous abortion with occupational exposure to organic solvents in pharmaceutical industry. Materials & Methods: This is a cross-sectional and descriptive-analytical study which was carried out in 2010 in one of the pharmaceutical factories located in the suburbs of Tehran. During the study, married women who were working in the factory laboratory units and were exposed to mixed organic solvents were compared with married women who were working in the packing units of the factory without occupational exposure to organic solvents. Frequency of spontaneous abortion and duration of pregnancy were assessed in both two groups. Collected data were analyzed with the SPSS software using t-test, logistic regression, and chi-square test. Results: In the present study, the frequency of spontaneous abortion in employees with exposure to organic solvents mixture was 10.7%. This study showed that even after adjustment for confounding factors, there was a significant correlation between spontaneous abortion and occupational exposure to organic solvents mixture and this correlation increased with increasing levels of exposure to organic solvents. Moreover, a significant correlation was observed between occupational exposure to mixed organic solvents and waiting time to become pregnant (TTP. Furthermore, this study showed that even after adjustment for confounding variables, shift workers were significantly more affected by spontaneous abortion compared to daytime workers (P < 0.001. Conclusion: According to the results of this study, since there is probability of spontaneous abortion resulting from occupational exposure to various chemicals including organic solvents, review of the status of occupational exposure of workers can be helpful

  12. A comparison of the activities of three beta-galactosidases in aqueous-organic solvent mixtures

    NARCIS (Netherlands)

    Yoon, JH; Mckenzie, D

    2005-01-01

    The hydrolytic activities of beta-galactosidases from three different sources have been determined in various 50% (v/v) organic solvent-buffer mixtures with a view to finding solvent systems of reduced water content suitable for the synthesis of glycosides and oligosaccharides. K. fragilis

  13. A comparison of the activities of three beta-galactosidases in aqueous-organic solvent mixtures

    NARCIS (Netherlands)

    Yoon, JH; Mckenzie, D

    2005-01-01

    The hydrolytic activities of beta-galactosidases from three different sources have been determined in various 50% (v/v) organic solvent-buffer mixtures with a view to finding solvent systems of reduced water content suitable for the synthesis of glycosides and oligosaccharides. K. fragilis beta-gala

  14. Solvatochromic sensor array for the identification of common organic solvents.

    Science.gov (United States)

    Rankin, Jacqueline M; Zhang, Qifan; LaGasse, Maria K; Zhang, Yinan; Askim, Jon R; Suslick, Kenneth S

    2015-04-21

    A cross-reactive colorimetric sensor array composed of solvatochromic dyes in semi-liquid matrices was used to successfully discriminate among eleven common solvents. The multidimensional array response is attributed to both chemical (i.e., analyte-dye interactions) and physical (i.e., spot blooming and refractive index alteration) changes in the sensor spot.

  15. Why do crown ethers activate enzymes in organic solvents?

    NARCIS (Netherlands)

    Unen, van Dirk-Jan; Engbersen, Johan F.J.; Reinhoudt, David N.

    2002-01-01

    One of the major drawbacks of enzymes in nonaqueous solvents is that their activity is often dramatically low compared to that in water. This limitation can be largely overcome by crown ether treatment of enzymes. In this paper, we describe a number of carefully designed new experiments that have im

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

    Directory of Open Access Journals (Sweden)

    Otto S. Wolfbeis

    2012-12-01

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

  17. PERTURBATION OF VOLTAGE-SENSITIVE CALCIUM FUNCTION IN PHEOCHROMOCYTOMA CELLS BY VOLATILE ORGANIC SOLVENTS.

    Science.gov (United States)

    Volatile organic solvents such as toluene (TOL) and trichloroethylene perturb nervous system function and share characteristic effects with other central nervous system depressants such as anesthetic gasses, ethanol, benzodiazepines and barbiturates. Recently, mechanistic studies...

  18. A NOVEL HYDROPHILIC POLYMER MEMBRANE FOR THE DEHYDRATION OF ORGANIC SOLVENTS

    Science.gov (United States)

    Novel hydrophilic polymer membranes based on polyallylamine ydrochloride- polyvinylalcohol are developed. The high selectivity and flux characteristics of these membranes for the dehydration of organic solvents are evaluated using pervaporation technology and are found to be ver...

  19. Solvent coarse-graining and the string method applied to the hydrophobic collapse of a hydrated chain

    OpenAIRE

    Miller, Thomas F.; Vanden-Eijnden, Eric; Chandler, David

    2007-01-01

    With computer simulations of >100,000 atoms, the mechanism for the hydrophobic collapse of an idealized hydrated chain was obtained by tiling space with (0.2 nm)3 cubes and projecting the atomistic water molecule positions onto this grid. With the coarse-grained field thus defined, the string method in collective variables was used to compute a minimum free-energy pathway (MFEP) for the collapsing chain. These calculations provide a proof of principle for a coarse-grained description of water...

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

    Science.gov (United States)

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

    2012-08-01

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

  1. Enzymatic Synthesis of Dipeptide Derivatives Containing Noncoded Amino Acids in Organic Solvents

    Institute of Scientific and Technical Information of China (English)

    YANG,Hong(杨洪); ZHOU,Chuang(周闯); TIAN,Gui-Ling(田桂玲); YE,Yun-Hua(叶蕴华)

    2002-01-01

    A series of dipeptide derivatives containing non-coded amino acis, N-Boc-4-X-Phe-Ala-NHNHNHPh (X= Cl, Br, I, NO2),were synthesized by using thermoase in organic solvents. The physical data were consistent with the same samples prepared by 3-( diethoxyphosphoryloxy)-1, 2, 3-benzotriazin-4 (3H)-one (DEPBT). Influence of different substituted groups of the non-coded amino acids and different organic solvents on the enzymatic peptide synthesis was studied.

  2. Organic fragments from graphene oxide: Isolation, characterization and solvent effects

    Indian Academy of Sciences (India)

    Ravula Thirupathi; Y Jayasubba Reddy; Erode N Prabhakaran; Hanudatta S Atreya

    2014-05-01

    As-prepared graphene oxide (GO) contains oxidative debris which can be washed using basic solutions. We present the isolation and characterization of these debris. Dynamic light scattering (DLS) is used to monitor the separation of the debris in various solvents in the presence of different protic and aprotic alkylamino bases. The study reveals that the debris are rich in carbonyl functional groups and water is an essential component for separation and removal of the debris from GO under oxidative reaction conditions.

  3. DNA damage and cytotoxicity in pathology laboratory technicians exposed to organic solvents

    Directory of Open Access Journals (Sweden)

    TATIANE DE AQUINO

    2016-03-01

    Full Text Available The aim of this study was to evaluate potential DNA damage and cytotoxicity in pathology laboratory technicians exposed to organic solvents, mainly xylene. Peripheral blood and buccal cells samples were collected from 18 technicians occupationally exposed to organic solvents and 11 non-exposed individuals. The technicians were sampled at two moments: Monday and Friday. DNA damage and cytotoxicity were evaluated using the Comet Assay and the Buccal Micronucleus Cytome assay. Fifteen subjects (83.5% of the exposed group to solvents complained about some symptom probably related to contact with vapours of organic solvents. DNA damage in the exposed group to solvents was nearly 2-fold higher on Friday than on Monday, and in both moments the individuals of this group showed higher levels of DNA damage in relation to controls. No statistical difference was detected in buccal cell micronucleus frequency between the laboratory technicians and the control group. However, in the analysis performed on Friday, technicians presented higher frequency (about 3-fold of karyolytic and apoptotic-like cells (karyorrhectic and pyknotic in relation to control group. Considering the damage frequency and the working time, a positive correlation was found in the exposed group to solvents (r=0.468; p=0.05. The results suggest that pathology laboratory workers inappropriately exposed to organic solvents have increased levels of DNA damage.

  4. Enhanced production and organic solvent stability of a protease fromBrevibacillus laterosporus strain PAP04

    Directory of Open Access Journals (Sweden)

    P. Anbu

    2016-01-01

    Full Text Available A bacterial strain (PAP04 isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99% to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source, skim milk (nitrogen source, pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74% followed by acetone (63% and chloroform (54.8%. In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50% concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media.

  5. Hydration free energies using semiempirical quantum mechanical Hamiltonians and a continuum solvent model with multiple atomic-type parameters.

    Science.gov (United States)

    Anisimov, Victor M; Cavasotto, Claudio N

    2011-06-23

    To build the foundation for accurate quantum mechanical (QM) simulation of biomacromolecules in an aqueous environment, we undertook the optimization of the COnductor-like Screening MOdel (COSMO) atomic radii and atomic surface tension coefficients for different semiempirical Hamiltonians adhering to the same computational conditions recently followed in the simulation of biomolecular systems. This optimization was achieved by reproducing experimental hydration free energies of a set consisting of 507 neutral and 99 ionic molecules. The calculated hydration free energies were significantly improved by introducing a multiple atomic-type scheme that reflects different chemical environments. The nonpolar contribution was treated according to the scaled particle Claverie-Pierotti formalism. Separate radii and surface tension coefficient sets have been developed for AM1, PM3, PM5, and RM1 semiempirical Hamiltonians, with an average unsigned error for neutral molecules of 0.64, 0.66, 0.73, and 0.71 kcal/mol, respectively. Free energy calculation of each molecule took on average 0.5 s on a single processor. The new sets of parameters will enhance the quality of semiempirical QM calculations using COSMO in biomolecular systems. Overall, these results further extend the utility of QM methods to chemical and biological systems in the condensed phase.

  6. D{sub 2}O−H{sub 2}O solvent isotope effects on the enthalpies of bicaret hydration and dilution of its aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Evgeniy V., E-mail: evi@isc-ras.ru [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Str., 153045 Ivanovo (Russian Federation); Batov, Dmitriy V. [Incorporated Physicochemical Center of Solution Researches, G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Str., 153045, Ivanovo (Russian Federation); Ivanovo' s State University of Chemistry and Technology, 7 Sheremetevsky Ave, 153000 Ivanovo (Russian Federation); Gazieva, Galina A.; Kravchenko, Angelina N. [Laboratory of Nitrogen-containing Compounds, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky Ave., 199119 Moscow (Russian Federation); Abrosimov, Vladimir K. [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Str., 153045 Ivanovo (Russian Federation)

    2014-08-20

    Graphical abstract: - Highlights: • Enthalpies of solution of bicaret (tetraethylglycoluril) in H{sub 2}O and D{sub 2}O were measured. • D{sub 2}O–H{sub 2}O enthalpy-isotopic effect is negative and decreasing with temperature. • Enthalpic coefficients h{sub 22} for pairwise solute–solute interactions were derived. • Quantity of h{sub 22} is negative and becoming the more negative in heavy water. • Prevailingly hydrophobic hydration of bicaret is weakened with rising temperature. - Abstract: The molar enthalpies of solution of bicaret or 2,4,6,8-tetraethyl-2,4,6,8-tatraazabicyclo[3.3.0]octane-3,7-dione in ordinary (H{sub 2}O) and heavy (D{sub 2}O) water at (278.15, 288.15, 298.15, 308.15, and 318.15) K as well as the enthalpies for dilution of its H/D isotopically distinguishable aqueous solutions at 298.15 K were measured calorimetrically. The standard (at infinite dilution) molar enthalpies and heat capacities of solution, and the enthalpic coefficients for pair (h{sub 22}) and triplet (h{sub 222}) interactions between hydrated solute molecules, along with D{sub 2}O–H{sub 2}O solvent isotope effects (IEs) on the studied quantities were computed. The enthalpic effects of bicaret dissolution and corresponding IEs were found to be negative and decreasing in magnitude with increasing temperature. On the contrary, the h{sub 22} and h{sub 222} values as well as IEs on them were found to be positive. These facts indicate that the bicaret hydration being predominantly hydrophobic is enhanced in the D{sub 2}O medium. The hydration behavior of the solute considered was discussed in comparison with that for mebicar or 2,4,6,8-tetramethyl-2,4,6,8-tatraazabicyclo[3.3.0]octane-3,7-dione using the previously obtained data.

  7. Hydration and diffusion processes shape microbial community organization and function in model soil aggregates

    Science.gov (United States)

    Ebrahimi, Ali; Or, Dani

    2015-12-01

    The constantly changing soil hydration status affects gas and nutrient diffusion through soil pores and thus the functioning of soil microbial communities. The conditions within soil aggregates are of particular interest due to limitations to oxygen diffusion into their core, and the presence of organic carbon often acting as binding agent. We developed a model for microbial life in simulated soil aggregates comprising of 3-D angular pore network model (APNM) that mimics soil hydraulic and transport properties. Within these APNM, we introduced individual motile (flagellated) microbial cells with different physiological traits that grow, disperse, and respond to local nutrients and oxygen concentrations. The model quantifies the dynamics and spatial extent of anoxic regions that vary with hydration conditions, and their role in shaping microbial community size and activity and the spatial (self) segregation of anaerobes and aerobes. Internal carbon source and opposing diffusion directions of oxygen and carbon within an aggregate were essential to emergence of stable coexistence of aerobic and anaerobic communities (anaerobes become extinct when carbon sources are external). The model illustrates a range of hydration conditions that promote or suppress denitrification or decomposition of organic matter and thus affect soil GHG emissions. Model predictions of CO2 and N2O production rates were in good agreement with limited experimental data. These limited tests support the dynamic modeling approach whereby microbial community size, composition, and spatial arrangement emerge from internal interactions within soil aggregates. The upscaling of the results to a population of aggregates of different sizes embedded in a soil profile is underway.

  8. Understanding Solvent Manipulation of Morphology in Bulk-Heterojunction Organic Solar Cells.

    Science.gov (United States)

    Chen, Yuxia; Zhan, Chuanlang; Yao, Jiannian

    2016-10-06

    Film morphology greatly influences the performance of bulk-heterojunction (BHJ)-structure-based solar cells. It is known that an interpenetrating bicontinuous network with nanoscale-separated donor and acceptor phases for charge transfer, an ordered molecular packing for exciton diffusion and charge transport, and a vertical compositionally graded structure for charge collection are prerequisites for achieving highly efficient BHJ organic solar cells (OSCs). Therefore, control of the morphology to obtain an ideal structure is a key problem. For this solution-processing BHJ system, the solvent participates fully in film processing. Its involvement is critical in modifying the nanostructure of BHJ films. In this review, we discuss the effects of solvent-related methods on the morphology of BHJ films, including selection of the casting solvent, solvent mixture, solvent vapor annealing, and solvent soaking. On the basis of a discussion on interaction strength and time between solvent and active materials, we believe that the solvent-morphology-performance relationship will be clearer and that solvent selection as a means to manipulate the morphology of BHJ films will be more rational.

  9. Quantifying Volatile Organic Compound Emissions from Solvents and their Impacts on Urban Air Quality

    Science.gov (United States)

    Mcdonald, B. C.; De Gouw, J. A.; Gilman, J.; Ahmadov, R.; Cappa, C. D.; Frost, G. J.; Goldstein, A. H.; Jathar, S.; Jimenez, J. L.; Kim, S. W.; McKeen, S. A.; Roberts, J. M.; Trainer, M.

    2016-12-01

    Solvents, which consist of personal care products, paints, degreasing agents, and other chemical products, are an important anthropogenic source of volatile organic compound (VOC) emissions. Yet there are many unresolved questions related to their emission rates, chemical composition, and relative importance on urban air quality problems. Using atmospheric measurements of speciated VOCs collected at a ground site located in the Los Angeles basin during the California Nexus (CalNex) Study in 2010, and utilizing data on the composition of solvent emissions from the California Air Resources Board (CARB), we are able to reconcile solvent emissions with ambient observations. Our analysis indicates that solvent emissions are underestimated by a factor of 2-3 in the CARB inventory. We then estimate the reactivity of solvent emissions with the hydroxyl (OH) radical, and also estimate the propensity of solvent emissions to form secondary organic aerosol (SOA). Solvents contain significant fractions of oxygenated compounds, including intermediate volatility compounds, which if released to the atmosphere are potentially reactive and can lead to the formation of SOA. Overall, our results suggest that in the Los Angeles basin, solvents are now the largest anthropogenic source of VOC emissions, OH reactivity, and SOA formation, and larger than the contribution from motor vehicles. This suggests that more research is needed in better constraining this potentially important source of urban VOC emissions.

  10. The effects of crown ethers on the activity of enzymes in organic solvents

    NARCIS (Netherlands)

    van Unen, D.J.; Engbersen, Johannes F.J.; Reinhoudt, David; Vulfson, Evgeny N.; Halling, Peter J.; Holland, Herbert L.

    2001-01-01

    Currently, the applicability of enzymes in synthetic organic chemistry is well recognized. The field of enzyme-catalyzed organic synthesis has been further boosted by the recognition that enzymes can operate in organic solvents. The use of nonaqueous media for enzymatic conversions offers a number

  11. Revisiting the effects of organic solvents on the thermal reduction of graphite oxide

    Energy Technology Data Exchange (ETDEWEB)

    Barroso-Bujans, Fabienne, E-mail: fbarroso@ehu.es [Centro de Fisica de Materiales-Material Physics Center (CSIC-UPV/EHU), Paseo Manuel Lardizabal 5, 20018 San Sebastian (Spain); Fierro, Jose Luis G. [Instituto de Catalisis y Petroleoquimica, CSIC. Marie Curie, 2, Cantoblanco, 28049 Madrid (Spain); Alegria, Angel [Centro de Fisica de Materiales-Material Physics Center (CSIC-UPV/EHU), Paseo Manuel Lardizabal 5, 20018 San Sebastian (Spain); Departamento de Fisica de Materiales, Universidad del Pais Vasco (UPV/EHU) Apartado 1072, 20080 San Sebastian (Spain); Colmenero, Juan [Centro de Fisica de Materiales-Material Physics Center (CSIC-UPV/EHU), Paseo Manuel Lardizabal 5, 20018 San Sebastian (Spain); Departamento de Fisica de Materiales, Universidad del Pais Vasco (UPV/EHU) Apartado 1072, 20080 San Sebastian (Spain); Donostia International Physics Center, Paseo Manuel Lardizabal 4, 20018 San Sebastian (Spain)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer Retention of organic solvent on graphite oxide interlayer space. Black-Right-Pointing-Pointer Decreasing exfoliation temperature. Black-Right-Pointing-Pointer Close link between structure and thermal behavior of solvent treated graphite oxide. Black-Right-Pointing-Pointer Restacking inhibition of thermally reduced graphite oxide sheets. Black-Right-Pointing-Pointer Changes in kinetic mechanisms of thermal reduction. - Abstract: Treatment of graphite oxide (GO) with organic solvents via sorption from either liquid or gas phase, and subsequent desorption, induces profound changes in the layered GO structure: loss of stacking order, retention of trace amounts of solvents and decreasing decomposition temperature. This study presents new evidences of the effect of organic solvents on the thermal reduction of GO by means of thermogravimetric analysis, X-ray diffraction and X-ray photoelectron spectroscopy. The results reveal a relative higher decrease of the oxygen amounts in solvent-treated GO as compared to untreated GO and the restacking inhibition of the thermally reduced GO sheets upon slow heating. The kinetic experiments evidence changes occurring in the reduction mechanisms of the solvent-treated GO, which support the close link between GO structure and thermal properties.

  12. Facile Fabrication of Ultrafine Copper Nanoparticles in Organic Solvent

    Directory of Open Access Journals (Sweden)

    Siegert Uwe

    2009-01-01

    Full Text Available Abstract A facile chemical reduction method has been developed to fabricate ultrafine copper nanoparticles whose sizes can be controlled down to ca. 1 nm by using poly(N-vinylpyrrolidone (PVP as the stabilizer and sodium borohyrdride as the reducing agent in an alkaline ethylene glycol (EG solvent. Transmission electron microscopy (TEM results and UV–vis absorption spectra demonstrated that the as-prepared particles were well monodispersed, mostly composed of pure metallic Cu nanocrystals and extremely stable over extended period of simply sealed storage.

  13. Measurement and prediction of aromatic solute distribution coefficients for aqueous-organic solvent systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.R.; Luthy, R.G.

    1984-06-01

    Experimental and modeling activities were performed to assess techniques for measurement and prediction of distribution coefficients for aromatic solutes between water and immiscible organic solvents. Experiments were performed to measure distribution coefficients in both clean water and wastewater systems, and to assess treatment of a wastewater by solvent extraction. The theoretical portions of this investigation were directed towards development of techniques for prediction of solute-solvent/water distribution coefficients. Experiments were performed to assess treatment of a phenolic-laden coal conversion wastewater by solvent extraction. The results showed that solvent extraction for recovery of phenolic material offered several wastewater processing advantages. Distribution coefficients were measured in clean water and wastewater systems for aromatic solutes of varying functionality with different solvent types. It was found that distribution coefficients for these compounds in clean water systems were not statistically different from distribution coefficients determined in a complex coal conversion process wastewater. These and other aromatic solute distribution coefficient data were employed for evaluation of modeling techniques for prediction of solute-solvent/water distribution coefficients. Eight solvents were selected in order to represent various chemical classes: toluene and benzene (aromatics), hexane and heptane (alkanes), n-octanol (alcohols), n-butyl acetate (esters), diisopropyl ether (ethers), and methylisobutyl ketone (ketones). The aromatic solutes included: nonpolar compounds such as benzene, toluene and naphthalene, phenolic compounds such as phenol, cresol and catechol, nitrogenous aromatics such as aniline, pyridine and aminonaphthalene, and other aromatic solutes such as naphthol, quinolinol and halogenated compounds. 100 references, 20 figures, 34 tables.

  14. Effect of Exposure to a Mixture of Organic Solvents on Hearing Thresholds in Petrochemical Industry Workers

    Directory of Open Access Journals (Sweden)

    Ziba Loukzadeh

    2014-10-01

    Full Text Available Introduction: Hearing loss is one of the most common occupational diseases. In most workplaces, workers are exposed to noise and solvents simultaneously, so the potential risk of hearing loss due to solvents may be attributed to noise.  In this study we aimed to assess the effect of exposure to mixed aromatic solvents on hearing in the absence of exposure to hazardous noise.   Materials and Methods: In a cross-sectional study, 99 workers from the petrochemical industry with exposure to a mixture of organic solvents whose noise exposure was lower than 85 dBA were compared with 100 un-exposed controls. After measuring sound pressure level and mean concentration of each solvent in the workplace, pure-tone-audiometry was performed and the two groups were compared in terms of high-frequency and low-frequency hearing loss. T-tests and Chi-square tests were used to compare the two groups.   Results: The mean hearing threshold at all frequencies among petrochemical workers was normal (below 25 dB. We did not observe any significant association between solvent exposure and high-frequency or low-frequency hearing loss.   Conclusion:  This study showed that temporary exposure (less than 4 years to a mixture of organic solvents, without exposure to noise, does not affect workers’ hearing threshold in audiometry tests.

  15. Effect of organic solvents on normal human stratum corneum: evaluation by the corneoxenometry bioassay.

    Science.gov (United States)

    Goffin, V; Letawe, C; Piérard, G E

    1997-01-01

    Organic solvents alter the stratum corneum structure and barrier function. To measure the effect of various solvents upon human stratum corneum using the ex vivo corneoxenometry bioassay which is a variant of corneosurfametry. Corneoxenometry entails collection of human stratum corneum by cyanoacrylate. The material is immersed in organic solvents for periods ranging from 1 to 120 min. After staining the samples with a toluidine blue-basic fuchsin solution, the color is measured using reflectance colorimetry. Solvent aggressivity to the stratum corneum correlates with the color darkening of the samples. The least aggressive solvent was hexane, followed by ethanol, methanol, hexane-ethanol, chloroform, chloroform-methanol and hexane-methanol. The influence of contact time between solvents and the stratum corneum showed a logarithmic pattern which varied according to the solvent. Data are in line with previous experiments conducted in vivo and in vitro, thus indicating the predictive value of corneoxenometry. Such a bioassay may avoid hazards of some in vivo human testings.

  16. Non-Hodgkin's lymphoma risk derived from exposure to organic solvents: a review of epidemiologic studies

    Directory of Open Access Journals (Sweden)

    Marco Antônio V. Rêgo

    Full Text Available The rate of non-Hodgkin's lymphomas (NHL has increased around the world during the last decades. Apart from the role of the human immunodeficiency virus (HIV infection in the development of NHL, exposure to chemical agents like phenoxyacetic pesticides, hair dyes, metal fumes and organic solvents are suspected to be involved. The present review evaluates the results of studies that directly or indirectly searched for an association between solvent exposure and NHL. The selected studies comprised those published from 1979 to 1997, designed to investigate risk factors for NHL, whether specifically looking for solvent exposure or for general risks in which solvent exposure could be included. In 25 of the 45 reviewed studies (55.5%, fifty-four statistically significant associations between NHL and solvent exposure related occupations or industries were reported. Statistical significance was more frequently shown in studies where solvent exposure was more accurately defined. In eighteen of such studies, 13 (72.2% defined or suggested organic solvents as possible risk factors for NHL.

  17. Structure of Solvent-Free Nanoparticle−Organic Hybrid Materials

    KAUST Repository

    Yu, Hsiu-Yu

    2010-11-16

    We derive the radial distribution function and the static structure factor for the particles in model nanoparticleorganic hybrid materials composed of nanoparticles and attached oligomeric chains in the absence of an intervening solvent. The assumption that the oligomers form an incompressible fluid of bead-chains attached to the particles that is at equilibrium for a given particle configuration allows us to apply a density functional theory for determining the equilibrium configuration of oligomers as well as the distribution function of the particles. A quasi-analytic solution is facilitated by a regular perturbation analysis valid when the oligomer radius of gyration R g is much greater than the particle radius a. The results show that the constraint that each particle carries its own share of the fluid attached to itself yields a static structure factor that approaches zero as the wavenumber approaches zero. This result indicates that each particle excludes exactly one other particle from its neighborhood. © 2010 American Chemical Society.

  18. Neurotoxicity of chronic low-dose exposure to organic solvents: a skeptical review.

    Science.gov (United States)

    Lees-Haley, P R; Williams, C W

    1997-11-01

    The health effects of long-term, low-level exposure to organic solvents have been studied for many years. While the volume of literature is great, definitive conclusions regarding chronic neurobehavioral effects of environmental exposure are premature. Methodological shortcomings in research preclude confidence in studies allegedly supporting a causal link between chronic low-dose solvent exposure and lasting neurobehavioral deficits. In this article, the shortcomings reviewed include selection bias in recruitment of research subjects, overreliance on subjective recall in determining levels and duration of exposure, between-study variability in kinds of solvents examined, variability in tests selected to assess neurobehavioral functioning, and diversity in reported findings. The implications of these for characterizing the state of organic solvent research are discussed.

  19. Organic Solvents Mediate Self-assembly of GAV-9 Peptide on Mica Surface

    Institute of Scientific and Technical Information of China (English)

    Hai LI; Feng ZHANG; Yi ZHANG; Jianhua HE; Jun HU

    2007-01-01

    Self-assembly of peptides into fibrils and other morphologies has attracted much attention in many fields, especially in nanofabrication, pathology and biochemistry. In this paper, self-assembly of GAV-9 peptide in organic solvents, ethanol and acetone, was investigated using atomic force microscopy (AFM)and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The results indicated that GAV-9 self- assembled into various nanostructures in both solvents after deposited and evaporated on mica. Fibrils with β-sheet conformation were observed in both solvents when the peptide concentration was higher than 280 μM. However, ordered fibrils with β-sheet conformation were formed in ethanol, but not in acetone, with a peptide concentration ranging from 7 μM to 28 μM. We attribute the formation of various nanostructures to the different physicochemical properties of the polar organic solvents on the self-assembly of GAV-9 peptide.

  20. Interactions between hydrated cement paste and organic acids: Thermodynamic data and speciation modeling

    Energy Technology Data Exchange (ETDEWEB)

    De Windt, Laurent, E-mail: laurent.dewindt@mines-paristech.fr [MINES ParisTech, PSL Research University, Centre de Géosciences, 35 Rue St-Honoré, 77305 Fontainebleau Cedex (France); Bertron, Alexandra; Larreur-Cayol, Steeves; Escadeillas, Gilles [University of Toulouse, UPS/INSA/LMDC, 135 Av. de Rangueil, 31077 Toulouse Cedex 04 (France)

    2015-03-15

    Interactions of short-chain organic acids with hydrated cement phases affect structure durability in the agro-food and nuclear waste industries but can also be used to modify cement properties. Most previous studies have been experimental, performed at fixed concentrations and pH, without quantitatively discriminating among polyacidity effects, or complexation and salt precipitation processes. This paper addresses such issues by thermodynamic equilibrium calculations for acetic, citric, oxalic, succinic acids and a simplified hydrated CEM-I. The thermodynamic constants collected from the literature allow the speciation to be modeled over a wide range of pH and concentrations. Citric and oxalic had a stronger chelating effect than acetic acid, while succinic acid was intermediate. Similarly, Ca-citrate and Ca-oxalate salts were more insoluble than Ca-acetate and Ca-succinate salts. Regarding aluminium complexation, hydroxyls, sulfates, and acid competition was highlighted. The exploration of acid mixtures showed the preponderant effect of oxalate and citrate over acetate and succinate.

  1. Understanding surface interactions in aqueous miscible organic solvent treated layered double hydroxides.

    OpenAIRE

    Erastova, Valentina; Degiacomi, Matteo T.; O'Hare, Dermot; Greenwell, H. Chris

    2016-01-01

    Layered materials are of interest for use in a wealth of technological applications, many of which require a high surface area for optimal properties and performance. Recently, an industrially scalable method to create high surface area layered double hydroxide (LDH) materials, which may be readily dispersed in non-polar solvents, has been developed. This method involves treatment of LDHs with aqueous miscible organic (AMO) solvents. Here, molecular modeling is exploited to elucidate the AMO ...

  2. Reversible brain damage following acute organic solvents' poisoning determined by magnetic resonance

    OpenAIRE

    2005-01-01

    Introduction. Acute exposure to the effects of volatile solvents is characterized by the abrupt onset of symptoms and signs of poisoning, and relatively fast recovery in the majority of cases. Case report. We report a 24-year-old patient with an acute, accidental poisoning with a mixture of volatile organic solvents (most probably toluene, styrene and xylene), which led to the development of upward gaze paresis, diplopia, hemiparesis, ataxic gate, and the late onset truncal ataxia episodes. A...

  3. Green analytical chemistry - the use of surfactants as a replacement of organic solvents in spectroscopy

    Science.gov (United States)

    Pharr, Daniel Y.

    2017-07-01

    This chapter gives an introduction to the many practical uses of surfactants in analytical chemistry in replacing organic solvents to achieve greener chemistry. Taking a holistic approach, it covers some background of surfactants as chemical solvents, their properties and as green chemicals, including their environmental effects. The achievements of green analytical chemistry with micellar systems are reviewed in all the major areas of analytical chemistry where these reagents have been found to be useful.

  4. Polar organic solvent added to an aqueous solution changes hydrolytic property of lipase.

    Science.gov (United States)

    Tsuzuki, Wakako; Ue, Akemi; Nagao, Akihiko

    2003-08-01

    For developing further uses of lipase as a biocatalyst, its hydrolytic activity toward some esters was investigated in a miscible solution composed of a buffer and a polar organic solvent. Twenty percent dimethylformamide, 35% dimethylsulfoxide, 15% 1,4-dioxane, 15% dimethoxyethane, and 2% diethoxyethane promoted the hydrolysis by a lipase from Rhizomucor miehei toward some hydrophobic substrates, 4-methylumbelliferyl oleate, 4-methylumbelliferyl palmitate, and monoolein. While hydrolysis by this lipase toward the substrates with a relatively weak hydrophobicity (4-metylumbelliferyl heptanoate and 4-methylumbelliferyl nanoate) was suppressed by these solvents. A fluorometric analysis showed that the polar organic solvent in the buffer induced some conformational change around a tryptophan residue of R. miehei lipase. In addition to the influence of the miscible solvent on the solubility of the substrates, the conformational change of the protein induced by the miscible solvent would also affect the reactive properties of the lipase. Adding a polar organic solvent to an aqueous solution will be an efficient method for changing hydrolytic performance of lipases.

  5. Carbon dioxide removal by alkanolamines in aqueous organic solvents. A method for enhancing the desorption process

    NARCIS (Netherlands)

    Hamborg, Espen S.; Derks, Peter W.J.; Elk, Edwin P. van; Versteeg, Geert F.

    2011-01-01

    Process concepts of using alkanolamines in aqueous organic solvents have been evaluated by experimental work and process simulations using the Procede Process Simulator. N-methyldiethanolamine (MDEA), methanol, and ethanol were chosen as the respective alkanolamine and organic compounds in the curre

  6. Impaired colour vision in workers exposed to organic solvents: A systematic review.

    Science.gov (United States)

    Betancur-Sánchez, A M; Vásquez-Trespalacios, E M; Sardi-Correa, C

    2017-01-01

    To evaluate recent evidence concerning the relationship between the exposure to organic solvents and the impairment of colour vision. A bibliographic search was conducted for scientific papers published in the last 15 years, in the LILACS, PubMed, Science Direct, EBSCO, and Cochrane databases that included observational studies assessing the relationship between impairment in colour vision and exposure to organic solvents. Eleven studies were selected that were performed on an economically active population and used the Lanthony D-15 desaturated test (D-15d), measured the exposure to organic solvents, and included unexposed controls. It was found that there is a statistically significant relationship between the exposure to organic solvents and the presence of an impairment in colour vision. The results support the hypothesis that exposure to organic solvents could induce acquired dyschromatopsia. The evaluation of colour vision with the D-15d test is simple and sensitive for diagnosis. More studies need to be conducted on this subject in order to better understand the relationship between impaired colour vision and more severe side effects caused by this exposure. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Sugar-Based Polyamides: Self-Organization in Strong Polar Organic Solvents.

    Science.gov (United States)

    Rosu, Cornelia; Russo, Paul S; Daly, William H; Cueto, Rafael; Pople, John A; Laine, Roger A; Negulescu, Ioan I

    2015-09-14

    Periodic patterns resembling spirals were observed to form spontaneously upon unassisted cooling of d-glucaric acid- and d-galactaric acid-based polyamide solutions in N-methyl-N-morpholine oxide (NMMO) monohydrate. Similar observations were made in d-galactaric acid-based polyamide/ionic liquid (IL) solutions. The morphologies were investigated by optical, polarized light and confocal microscopy assays to reveal pattern details. Differential scanning calorimetry was used to monitor solution thermal behavior. Small- and wide-angle X-ray scattering data reflected the complex and heterogeneous nature of the self-organized patterns. Factors such as concentration and temperature were found to influence spiral dimensions and geometry. The distance between rings followed a first-order exponential decay as a function of polymer concentration. Fourier-Transform Infrared Microspectroscopy analysis of spirals pointed to H-bonding between the solvent and the pendant hydroxyl groups of the glucose units from the polymer backbone. Tests on self-organization into spirals of ketal-protected d-galactaric acid polyamides in NMMO monohydrate confirmed the importance of the monosaccharide's pendant free hydroxyl groups on the formation of these patterns. Rheology performed on d-galactaric-based polyamides at high concentration in NMMO monohydrate solution revealed the optimum conditions necessary to process these materials as fibers by spinning. The self-organization of these sugar-based polyamides mimics certain biological materials.

  8. Removal of ion-implanted photoresists on GaAs using two organic solvents in sequence

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Eunseok; Na, Jihoon; Lee, Seunghyo; Lim, Sangwoo, E-mail: swlim@yonsei.ac.kr

    2016-07-15

    Highlights: • Two-step photoresist removal process using two organic solvents was developed. • Photoresist on trench patterned GaAs was removed by two-step sequence. • Acetonitrile with dimethyl sulfoxide removed implanted photoresists at 30 °C. • Affinity and permeability of solvent through photoresist determine photoresist removal. - Abstract: Organic solvents can effectively remove photoresists on III–V channels without damage or etching of the channel material during the process. In this study, a two-step sequential photoresist removal process using two different organic solvents was developed to remove implanted ArF and KrF photoresists at room temperature. The effects of organic solvents with either low molar volumes or high affinities for photoresists were evaluated to find a proper combination that can effectively remove high-dose implanted photoresists without damaging GaAs surfaces. The performance of formamide, acetonitrile, nitromethane, and monoethanolamine for the removal of ion-implanted ArF and KrF photoresists were compared using a two-step sequential photoresist removal process followed by treatment in dimethyl sulfoxide (DMSO). Among the various combinations, the acetonitrile + DMSO two-step sequence exhibited the best removal of photoresists that underwent ion implantation at doses of 5 × 10{sup 13}–5 × 10{sup 15} atoms/cm{sup 2} on both flat and trench-structured GaAs surfaces. The ability of the two-step process using organic solvents to remove the photoresists can be explained by considering the affinities of solvents for a polymer and its permeability through the photoresist.

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

    KAUST Repository

    Kim, Hyeongjun

    2012-01-10

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

  10. The Effect of Solvent on the Analysis of Secondary Organic Aerosol Using Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, Adam P. [Univ. of California, Irvine, CA (United States); Walser, Maggie L. [Univ. of California, Irvine, CA (United States); Dessiaterik, Yury [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Laskin, Julia [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Laskin, Alexander [Univ. of California, Irvine, CA (United States); Nizkorodov, Serguei [Univ. of California, Irvine, CA (United States)

    2008-08-29

    Solvent-analyte reactions in organic aerosol (OA) extracts prepared for analysis by electrospray ionization mass spectrometry (ESI-MS) were examined. Secondary organic aerosol (SOA) produced by ozonation of d-limonene as well as several test organic chemicals with functional groups typical for OA constituents were dissolved and stored in methanol, d3-methanol, acetonitrile, and d3-acetonitrile to investigate the extent and relative rates of reactions between analyte and solvent. High resolution ESI-MS showed that reactions of carbonyls with methanol produce significant amounts of hemiacetals and acetals on time scales ranging from several minutes to several days, with the reaction rates increasing in acidified solutions. Carboxylic acid groups were observed to react with methanol resulting in the formation of esters. In contrast, acetonitrile extracts showed no evidence of reactions with analyte molecules, suggesting that acetonitrile is the preferred solvent for SOA extraction. The use of solvent-analyte reactivity as an analytical chemistry tool for the improved characterization of functional groups in complex organic mixtures was also demonstrated. Direct comparison between ESI mass spectra of the same SOA samples extracted in reactive (methanol) versus non-reactive (acetonitrile) solvents was used to estimate the relative fractions of ketones (≥38%), aldehydes (≥6%), and carboxylic acids (≥55%) in d-limonene SOA.

  11. Crosslinked copolyazoles with a zwitterionic structure for organic solvent resistant membranes

    KAUST Repository

    Chisca, Stefan

    2015-01-01

    The preparation of crosslinked membranes with a zwitterionic structure based on a facile reaction between a newly synthesized copolyazole with free OH groups and (3-glycidyloxypropyl)trimethoxysilane (GPTMS) is reported. The new OH-functionalized copolyazole is soluble in common organic solvents, such as tetrahydrofuran (THF), dimethylsulfoxide (DMSO), N,N′-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP) and can be easily processed by phase inversion. After crosslinking with GPTMS, the membranes acquire high solvent resistance. We show the membrane performance and the influence of the crosslinking reaction conditions on the thermal stability, surface polarity, pore morphology, and solvent resistance. By using UV-spectroscopy we monitored the solvent resistance of the membranes in four aggressive solvents (THF, DMSO, DMF and NMP) for 30 days. After this time, only minor changes (less than 2%) were detected for membranes subjected to a crosslinking reaction for 6 hours or longer. Our data suggest that the novel crosslinked membranes can be used for industrial applications in wide harsh environments in the presence of organic solvents.

  12. Molecular transport behaviour of organic solvents through halloysite nanotubes filled ethylene–vinyl acetate copolymer

    Indian Academy of Sciences (India)

    Suvendu Padhi; P Ganga Raju Achary; Nimai C Nayak

    2015-08-01

    The transport behaviour of three organic solvents (benzene, toluene and xylene) through halloysite nanotubes (HNTs) filled ethylene–vinyl acetate (EVA) copolymer composites have been investigated in the temperature range 303–323 K. The effects of HNTs loading, nature of solvent and temperature on the transport behaviour of solvents through composites were studied. It has been observed that all the systems follow a Fickian mode of transport on increasing temperature. The solvent uptake and sorption coefficient decreases with the increase in halloysite loading while diffusion coefficients and permeation coefficients were found to be dependent on the concentration of filler. The percentage of bounds rubber content and swelling ratio decreases up to 7.5 phr filler content, whereas above 7.5 phr filler loading were found to be increased due to poor dispersion of halloysite in EVA copolymer matrix. The transport behaviour of three organic solvents was further validated by their crosslink density values. The thermodynamic parameters such as enthalpy, entropy and free energy of sorption were evaluated. The positive values of free energy indicate the non-spontaneity of the sorption of HNTs filled EVA in aromatic solvents at 303 K.

  13. Prioritizing substitution of organic solvents in industrial cleaning processes

    DEFF Research Database (Denmark)

    Rasmussen, Pia Brunn; Jacobsen, Thomas

    1997-01-01

    A method for prioritizing the substitution of volatile organic compounds (VOC) used in industrial cleaning processes is developed. The result is a matrix, which, if all information can be obtained, gives a comprehensive description of the effects, exposure and emission of VOC, as well...

  14. Azeotropic binary solvent mixtures for preparation of organic single crystals

    NARCIS (Netherlands)

    Li, X.; Kjellander, B.K.C.; Anthony, J.E.; Bastiaansen, C.W.M.; Broer, D.J.; Gelinck, G.H.

    2009-01-01

    Here, a new approach is introduced to prepare large single crystals of π-conjugated organic molecules from solution. Utilizing the concept of azeotropism, single crystals of tri-isopropylsilylethynyl pentacene (TIPS-PEN) with dimensions up to millimeters are facilely self-assembled from homogeneous

  15. Dynamic solvation shell and solubility of C60 in organic solvents.

    Science.gov (United States)

    Wang, Chun I; Hua, Chi C; Chen, Show A

    2014-08-21

    The notion of (static) solvation shells has recently proved fruitful in revealing key molecular factors that dictate the solubility and aggregation properties of fullerene species in polar or ionic solvent media. Using molecular dynamics schemes with carefully evaluated force fields, we have scrutinized both the static and the dynamic features of the solvation shells of single C60 particle for three nonpolar organic solvents (i.e., chloroform, toluene, and chlorobenzene) and a range of system temperatures (i.e., T = 250-330 K). The central findings have been that, while the static structures of the solvation shell remain, in general, insensitive to the effects of changing solvent type or system temperature, the dynamic behavior of solvent molecules within the shell exhibits prominent dependence on both factors. Detailed analyses led us to propose the notion of dynamically stable solvation shell, effectiveness of which can be characterized by a new physical parameter defined as the ratio of two fundamental time constants representing, respectively, the solvent relaxation (or residence) time within the first solvation shell and the characteristic time required for the fullerene particle to diffuse a distance comparable to the shell thickness. We show that, for the five (two from the literature) different solvent media and the range of system temperatures examined herein, this parameter bears a value around unity and, in particular, correlates intimately with known trends of solubility for C60 solutions. We also provide evidence revealing that, in addition to fullerene-solvent interactions, solvent-solvent interactions play an important role, too, in shaping the dynamic solvation shell, as implied by recent experimental trends.

  16. Quantitative determination of urinary metabolites in subjects exposed to organic solvents.

    Directory of Open Access Journals (Sweden)

    Ogata,Masana

    1981-12-01

    Full Text Available Most of the common organic solvents are excreted into urine as metabolites. A correlation exists for several organic solvents between the amount taken in and the amount of metabolites excreted. Many methods have been developed for the measurement of these urinary metabolites. The methods were classified into three group: colorimetry, gas chromatography and high performance liquid chromatography. The characteristics and availability of these methods in a laboratory for routine work were reviewed. The correction equation for the amounts of metabolites in spot urine is discussed.

  17. A Solvent-Free Claisen Condensation Reaction for the Organic Laboratory

    Science.gov (United States)

    Esteb, John J.; Stockton, Matthew B.

    2003-12-01

    An experiment involving the Claisen condensation reaction for a first-year organic chemistry laboratory is presented. Claisen condensations are routinely covered in organic textbooks but owing to the long reaction times required to reach equilibrium in solution they are seldom explored in the undergraduate teaching laboratory. In this experiment, potassium tert-butoxide and ethyl phenylacetate are heated to 100 °C for 30 minutes under solvent-free conditions to produce 2,4-diphenyl acetoacetate in 80% yield. The solvent-free nature of this procedure greatly reduces the quantity of waste generated by students relative to typical carbonyl condensation experiments.

  18. High-Throughput Synthetic Chemistry Enabled by Organic Solvent Disintegrating Tablet.

    Science.gov (United States)

    Li, Tingting; Xu, Lei; Xing, Yanjun; Xu, Bo

    2017-01-17

    Synthetic chemistry remains a time- and labor-intensive process of inherent hazardous nature. Our organic solvent disintegrating tablet (O-Tab) technology has shown potential to make industrial/synthetic chemistry more efficient. As is the case with pharmaceutical tablets, our reagent-containing O-Tabs are mechanically strong, but disintegrate rapidly when in contact with reaction media (organic solvents). For O-Tabs containing sensitive chemicals, they can be further coated to insulate them from air and moisture. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. In-Vitro Characterization and Oral Bioavailability of Organic Solvent-free Solid Dispersions Containing Telmisartan

    DEFF Research Database (Denmark)

    Cao, Yue; Shi, Li-Li; Cao, Qing-Ri

    2016-01-01

    Poorly water-soluble drugs often suffer from limited or irreproducible clinical response due to their low solubility and dissolution rate. In this study, organic solvent-free solid dispersions (OSF-SDs) containing telmisartan (TEL) were prepared using polyvinylpyrrolidone K30 (PVP K30) and polyet......Poorly water-soluble drugs often suffer from limited or irreproducible clinical response due to their low solubility and dissolution rate. In this study, organic solvent-free solid dispersions (OSF-SDs) containing telmisartan (TEL) were prepared using polyvinylpyrrolidone K30 (PVP K30...

  20. Organic solvents-free technique for determining sulfadimethoxine and its metabolites in chicken meat.

    Science.gov (United States)

    Furusawa, Naoto

    2007-11-16

    A quick and cost-effective technique of sample preparation followed by a reversed-phase high performance liquid chromatography under "organic solvent-free" (=100% aqueous) conditions for the simultaneous quantifying of sulfadimethoxine (SDM) and its metabolites, 6-hydroxy SDM (6-OH) and N(4)-acetyl SDM (N(4)-Ac), in chicken muscle is presented. Analysis by HPLC with photo-diode array detector was performed using a short C1 column with an isocratic 0.04 mol/l citric acid mobile phase. The method was validated by the analyses of spiked chicken muscle samples, resulting recoveries (> or =84%; relative standard deviations organic solvents were used at all.

  1. Reactions of metallic Li or LiC6 with organic solvents for lithium ion battery

    Science.gov (United States)

    Nakajima, Tsuyoshi; Hirobayashi, Yuki; Takayanagi, Yuki; Ohzawa, Yoshimi

    2013-12-01

    DSC (Differential Scanning Calorimetry) study has been made on the reactions of metallic Li or LiC6 with organic solvents for lithium ion battery. Ethylene carbonate (EC) more easily reacts with metallic Li and LiC6 than propylene carbonate (PC). This may be because formation of lithium alkyl carbonate is more difficult for PC than EC. On the other hand, diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) react with Li in the same manner. Reactions of Li and LiC6 with organic solvents have been discussed based on the results of quantum calculation.

  2. Spectrophotometric determination of the acidity constants of calcon in water and mixed water–organic solvents

    Directory of Open Access Journals (Sweden)

    MOHAMMAD MAZLOUM-ARDAKANI

    2009-02-01

    Full Text Available The acid–base properties of calcon (1-(2-hydroxy-1-naphthylazo-2-naphthol-4-sulfonic acid in water and mixed water–organic solvents at 25 °C at an ionic strength of 0.10 M are studied by a multiwavelength spectrophotometric method. The organic solvents used were the amphiprotic (methanol, dipolar aprotic (dimethylsulfoxide, and low basic aprotic (acetonitrile. To evaluate the pH absorbance data, a resolution method based on the combination of soft- and hard-modeling was applied. The acidity constants of all related equilibria were estimated using the whole spectral fitting of the collected data to an established factor analysis model. The data analysis program Datan was applied for determination of the acidity constants. The corresponding pKa values were determined in water and mixed water–organic solvents. Linear relationship between the acidity constants and the mole fraction of the different sol-vents in the mixtures exist. The effect of solvent properties on acid–base behavior is discussed.

  3. Cooperation in carbon source degradation shapes spatial self-organization of microbial consortia on hydrated surfaces

    Science.gov (United States)

    Tecon, Robin; Or, Dani

    2017-01-01

    Mounting evidence suggests that natural microbial communities exhibit a high level of spatial organization at the micrometric scale that facilitate ecological interactions and support biogeochemical cycles. Microbial patterns are difficult to study definitively in natural environments due to complex biodiversity, observability and variable physicochemical factors. Here, we examine how trophic dependencies give rise to self-organized spatial patterns of a well-defined bacterial consortium grown on hydrated surfaces. The model consortium consisted of two Pseudomonas putida mutant strains that can fully degrade the aromatic hydrocarbon toluene. We demonstrated that obligate cooperation in toluene degradation (cooperative mutualism) favored convergence of 1:1 partner ratio and strong intermixing at the microscale (10–100 μm). In contrast, competition for benzoate, a compound degraded independently by both strains, led to distinct segregation patterns. Emergence of a persistent spatial pattern has been predicted for surface attached microbial activity in liquid films that mediate diffusive exchanges while permitting limited cell movement (colony expansion). This study of a simple microbial consortium offers mechanistic glimpses into the rules governing the assembly and functioning of complex sessile communities, and points to general principles of spatial organization with potential applications for natural and engineered microbial systems. PMID:28262696

  4. Proteomic analysis of Pseudomonas putida reveals an organic solvent tolerance-related gene mmsB.

    Directory of Open Access Journals (Sweden)

    Ye Ni

    Full Text Available Organic solvents are toxic to most microorganisms. However, some organic-solvent-tolerant (OST bacteria tolerate the destructive effects of organic solvent through various accommodative mechanisms. In this work, we developed an OST adapted strain Pseudomonas putida JUCT1 that could grow in the presence of 60% (v/v cyclohexane. Two-dimensional gel electrophoresis was used to compare and analyze the total cellular protein of P. putida JUCT1 growing with or without 60% (v/v cyclohexane. Under different solvent conditions, five high-abundance protein spots whose intensity values show over 60% discrepancies were identified by MALDI-TOF/TOF spectra. Specifically, they are arginine deiminase, carbon-nitrogen hydrolase family putative hydrolase, 3-hydroxyisobutyrate dehydrogenase, protein chain elongation factor EF-Ts, and isochorismatase superfamily hydrolase. The corresponding genes of the latter three proteins, mmsB, tsf, and PSEEN0851, were separately expressed in Escherichia coli to evaluate their effect on OST properties of the host strain. In the presence of 4% (v/v cyclohexane, E. coli harboring mmsB could grow to 1.70 OD(660, whereas cell growth of E. coli JM109 (the control was completely inhibited by 2% (v/v cyclohexane. Transformants carrying tsf or PSEEN0851 also showed an increased resistance to cyclohexane and other organic solvents compared with the control. Of these three genes, mmsB exhibited the most prominent effect on increasing OST of E. coli. Less oxidation product of cyclohexane was detected because mmsB transformants might help keep a lower intracellular cyclohexane level. This study demonstrates a feasible approach for elucidating OST mechanisms of microorganisms, and provides molecular basis to construct organic-solvent-tolerant strains for industrial applications.

  5. The Role of Concentration and Solvent Character in the Molecular Organization of Humic Acids

    Directory of Open Access Journals (Sweden)

    Martina Klučáková

    2016-10-01

    Full Text Available The molecular organization of humic acids in different aqueous solutions was studied over a wide concentration range (0.01–10 g·dm−3. Solutions of humic acids were prepared in three different media: NaOH, NaCl, and NaOH neutralized by HCl after dissolution of the humic sample. Potentiometry, conductometry, densitometry, and high resolution ultrasound spectrometry were used in order to investigate conformational changes in the humic systems. The molecular organization of humic acids in the studied systems could be divided into three concentration ranges. The rearrangements were observed at concentrations of ~0.02 g·dm−3 and ~1 g·dm−3. The first “switch-over point” was connected with changes in the hydration shells of humic particles resulting in changes in their elasticity. The compressibility of water in the hydration shells is less than the compressibility of bulk water. The transfer of hydration water into bulk water increased the total compressibility of the solution, reducing the ultrasonic velocity. The aggregation of humic particles and the formation of rigid structures in systems with concentrations higher than 1 g·dm−3 was detected.

  6. Cell hydration as a biomarker for estimation of biological effects of nonionizing radiation on cells and organisms.

    Science.gov (United States)

    Ayrapetyan, Sinerik; De, Jaysankar

    2014-01-01

    "Changes in cell hydration" have been hypothesized as an input signal for intracellular metabolic cascade responsible for biological effects of nonionizing radiation (NIR). To test this hypothesis a comparative study on the impacts of different temperature and NIR (infrasound frequency mechanical vibration (MV), static magnetic field (SMF), extremely low frequency electromagnetic field (ELF EMF), and microwave (MW)) pretreated water on the hydration of barley seeds in its dormant and germination periods was performed. In dormant state temperature sensitivity (Q 10) of seed hydration in distilled water (DW) was less than 2, and it was nonsensitive to NIR treated DW, whereas during the germination period (48-72 hours) seeds hydration exhibited temperature sensitivity Q 10 > 2 and higher sensitivity to NIR treated DW. Obtained data allow us to suggest that the metabolic driving of intracellular water dynamics accompanied by hydrogen bonding and breaking is more sensitive to NIR-induced water structure changes in seed bathing aqua medium than the simple thermodynamic processes such as osmotic gradient driven water absorption by seeds in dormant state. Therefore, cell hydration is suggested to be a universal and extrasensitive biomarker for detection of biological effects of NIR on cells and organisms.

  7. Spectroscopic Study of Methylglyoxal and its Hydrates : a Gaseous Precursor of Secondary Organic Aerosols.

    Science.gov (United States)

    Bteich, Sabath; Goubet, Manuel; Margulès, L.; Motiyenko, R. A.; Huet, T. R.

    2016-06-01

    Secondary organic aerosols (SOA) have a significant effect on climate change. They are mainly produced in the atmosphere by oxidation of gaseous precursors. Fu et al. have suggested trans-methylglyoxal (MG) as a possible precursor of SOA in the cloud for its presence in large quantities in the atmosphere. The characterization of SOAs precursors by laboratory spectroscopy allows providing elements for the understanding of the process of formation of these aerosols. For this purpose, we completed the existing pure rotational spectrum of MG in the 12-40 GHz range by new records in a supersonic jet in the 4-20 GHz range (FTMW) and at room temperature in the 150-500 GHz range (mm/submm-wave spectrometer). The analysis was made with the support of quantum chemistry calculations (MP2/CBS and B98/CBS using the Gaussian 09 software). The adjustment of the spectroscopic parameters, taking into account the internal rotation related to the presence of a methyl group, was performed using the RAM36 code. The spectra have been reproduced at the experimental precision up to maximal values of J and K_a equal to 85 and 35, respectively. The data obtained for the isolated molecule, both experimentally and theoretically, will allow the study of its hydrated complexes and, by comparison, will give access to (micro-) hydration properties. For this purpose, two stable complexes predicted by theoretical calculations will be studied. T.- M. Fu et al., J. Geophys. Res., 113, (2008). C.E. Dyltick-Brenzinger and A. Bauder, Chem. Phys. 30, 147 (1978).

  8. Organic aqueous tunable solvents (OATS): a vehicle for coupling reactions and separations.

    Science.gov (United States)

    Pollet, Pamela; Hart, Ryan J; Eckert, Charles A; Liotta, Charles L

    2010-09-21

    In laboratory-based chemical synthesis, the choice of the solvent and the means of product purification are rarely determined by cost or environmental impact considerations. When a reaction is scaled up for industrial applications, however, these choices are critical: the separation of product from the solvent, starting materials, and byproduct usually constitutes 60-80% of the overall cost of a process. In response, researchers have developed solvents and solvent-handling methods to optimize both the reaction and the subsequent separation steps on the manufacturing scale. These include "switchable" solvents, which are designed so that their physical properties can be changed abruptly, as well as "tunable" solvents, wherein the solvent's properties change continuously through the application of an external stimulus. In this Account, we describe the organic aqueous tunable solvent (OATS) system, examining two instructive and successful areas of application of OATS as well as its clear potential for further refinement. OATS systems address the limitations of biphasic processes by optimizing reactions and separations simultaneously. The reaction is performed homogeneously in a miscible aqueous-organic solvent mixture, such as water-tetrahydrofuran (THF). The efficient product separation is conducted heterogeneously by the simple addition of modest pressures of CO(2) (50-60 bar) to the system. Under these conditions, the water-THF phase splits into two relatively immiscible phases: the organic THF phase contains the hydrophobic product, and the aqueous phase contains the hydrophilic catalyst. We take advantage of the unique properties of OATS to develop environmentally benign and cost-competitive processes relevant in industrial applications. Specifically, we describe the use of OATS for optimizing the reaction, separation, design, and recycling of (i) Rh-catalyzed hydroformylation of olefins such as 1-octene and (ii) enzyme-catalyzed hydrolysis of 2-phenylacetate. We

  9. Ice nucleation activity of diesel soot particles at Cirrus relevant conditions: Effects of hydration, secondary organics coating, hydration, soot morphology, and coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, Gourihar R.; China, Swarup; Liu, Shang; Nandasiri, Manjula I.; Sharma, Noopur; Wilson, Jacqueline M.; Aiken, A. C.; Chand, Duli; Laskin, Alexander; Mazzoleni, Claudio; Pekour, Mikhail S.; Shilling, John E.; Shutthanandan, V.; Zelenyuk, Alla; Zaveri, Rahul A.

    2016-04-16

    The role of atmospheric relevant soot particles that are processed in the atmosphere toward ice nucleation at cirrus cloud condition is poorly understood. In this study, the ice nucleating properties of diesel soot particles subjected to various physical and chemical aging treatments were investigated at temperatures ranging from -40 to -50 °C. We show that bare soot particles nucleate ice in deposition mode, but coating with secondary organics suppresses the heterogeneous ice nucleation potential of soot particles requiring homogeneous freezing threshold conditions. However, the ice nucleation efficiency of soot particles coated with an aqueous organic layer was similar to bare soot particles. Hydration of bare soot particles slightly enhanced the ice nucleation efficiency, and the IN abilities of compact soot particles (roundness = ~ 0.6) were similar to bare lacey soot particles (roundness = ~ 0.4). These results indicate that ice nucleation properties are sensitive to the various aging treatments.

  10. Prioritizing substitution of organic solvents in industrial cleaning processes

    DEFF Research Database (Denmark)

    Rasmussen, Pia Brunn; Jacobsen, Thomas

    1997-01-01

    A method for prioritizing the substitution of volatile organic compounds (VOC) used in industrial cleaning processes is developed. The result is a matrix, which, if all information can be obtained, gives a comprehensive description of the effects, exposure and emission of VOC, as well...... as the prospects for performing the substitution with a vegetable ester. It can be a tool for companies to decide which cleaning process has the highest demand for substitution, if there is a choice between several processes, but it may also be a tool to convince companies to use non-volatile, low-toxic cleaning...

  11. Substitution of Organic Solvents - a Way to improve Working Environment and reduce Emissions to the Atmosphere

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    1996-01-01

    the process in order to omit the solvents or to use water-based products. In cases, where a change to water-based is not evident, improvements can be reached by using non-volatile, low-toxic products, typically esters of fatty acids from vegetable oils. In offset printing a drastic reduction of use of organic......Often there is a conflict between considerations regarding the working environment, and considerations regarding the environment, locally and globally, outside the company. When processes involving use of volatile, organic solvents are closely analyzed, it may in many cases be possible to change...... solvents as cleaning agents has been reached. However, some barriers to this substitution process, are found outside the printing companies. In designing of machines and auxiliary equipment, the manufacturers must take into account, that cleaning with non-volatile agents should be possible. Even a rather...

  12. Psychophysical Evaluation of Achromatic and Chromatic Vision of Workers Chronically Exposed to Organic Solvents

    Science.gov (United States)

    Lacerda, Eliza Maria da Costa Brito; Lima, Monica Gomes; Rodrigues, Anderson Raiol; Teixeira, Cláudio Eduardo Correa; de Lima, Lauro José Barata; Ventura, Dora Fix; Silveira, Luiz Carlos de Lima

    2012-01-01

    The purpose of this paper was to evaluate achromatic and chromatic vision of workers chronically exposed to organic solvents through psychophysical methods. Thirty-one gas station workers (31.5 ± 8.4 years old) were evaluated. Psychophysical tests were achromatic tests (Snellen chart, spatial and temporal contrast sensitivity, and visual perimetry) and chromatic tests (Ishihara's test, color discrimination ellipses, and Farnsworth-Munsell 100 hue test—FM100). Spatial contrast sensitivities of exposed workers were lower than the control at spatial frequencies of 20 and 30 cpd whilst the temporal contrast sensitivity was preserved. Visual field losses were found in 10–30 degrees of eccentricity in the solvent exposed workers. The exposed workers group had higher error values of FM100 and wider color discrimination ellipses area compared to the controls. Workers occupationally exposed to organic solvents had abnormal visual functions, mainly color vision losses and visual field constriction. PMID:22220188

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

  14. Psychophysical Evaluation of Achromatic and Chromatic Vision of Workers Chronically Exposed to Organic Solvents

    Directory of Open Access Journals (Sweden)

    Eliza Maria da Costa Brito Lacerda

    2012-01-01

    Full Text Available The purpose of this paper was to evaluate achromatic and chromatic vision of workers chronically exposed to organic solvents through psychophysical methods. Thirty-one gas station workers (31.5 ± 8.4 years old were evaluated. Psychophysical tests were achromatic tests (Snellen chart, spatial and temporal contrast sensitivity, and visual perimetry and chromatic tests (Ishihara's test, color discrimination ellipses, and Farnsworth-Munsell 100 hue test—FM100. Spatial contrast sensitivities of exposed workers were lower than the control at spatial frequencies of 20 and 30 cpd whilst the temporal contrast sensitivity was preserved. Visual field losses were found in 10–30 degrees of eccentricity in the solvent exposed workers. The exposed workers group had higher error values of FM100 and wider color discrimination ellipses area compared to the controls. Workers occupationally exposed to organic solvents had abnormal visual functions, mainly color vision losses and visual field constriction.

  15. Enhancement of room temperature ferromagnetism in tin oxide nanocrystal using organic solvents

    Science.gov (United States)

    Sakthiraj, K.; Hema, M.; Balachandra Kumar, K.

    2017-10-01

    The effect of organic solvents (ethanol & ethylene glycol) on the room temperature ferromagnetism in nanocrystalline tin oxide has been studied. The samples were synthesized using sol-gel method with the mixture of water & organic liquid as solvent. It is found that pristine SnO2 nanocrystal contain two different types of paramagnetic centres over their surface:(i) surface chemisorbed oxygen species and (ii) Sn interstitial & oxygen vacancy defect pair. The magnetic moment induced in the as-prepared samples is mainly contributed by the alignment of local spin moments resulting from these defects. These surface defect states are highly activated by the usage of ethylene glycol solvent rather than ethylene in tin oxide nanostructure synthesis. Powder X-ray diffraction, transmission electron microscope imaging, energy dispersive spectrometry, Fourier transformed infrared spectroscopy, UV-vis absorption spectroscopy, photoluminescence spectroscopy, vibrating sample magnetometer measurement and electron spin resonance spectroscopy were employed to characterize the nanostructured tin oxide materials.

  16. Microscopic relaxations in a protein sustained down to 160K in a non-glass forming organic solvent.

    Science.gov (United States)

    Mamontov, E; O'Neill, H

    2017-01-01

    We have studied microscopic dynamics of a protein in carbon disulfide, a non-glass forming solvent, down to its freezing temperature of ca. 160K. We have utilized quasielastic neutron scattering. A comparison of lysozyme hydrated with water and dissolved in carbon disulfide reveals a stark difference in the temperature dependence of the protein's microscopic relaxation dynamics induced by the solvent. In the case of hydration water, the common protein glass-forming solvent, the protein relaxation slows down in response to a large increase in the water viscosity on cooling down, exhibiting a well-known protein dynamical transition. The dynamical transition disappears in non-glass forming carbon disulfide, whose viscosity remains a weak function of temperature all the way down to freezing at just below 160K. The microscopic relaxation dynamics of lysozyme dissolved in carbon disulfide is sustained down to the freezing temperature of its solvent at a rate similar to that measured at ambient temperature. Our results demonstrate that protein dynamical transition is not merely solvent-assisted, but rather solvent-induced, or, more precisely, is a reflection of the temperature dependence of the solvent's glass-forming dynamics. We hypothesize that, if the long debated idea regarding the direct link between the microscopic relaxations and the biological activity in proteins is correct, then not only the microscopic relaxations, but also the activity, could be sustained in proteins all the way down to the freezing temperature of a non-glass forming solvent with a weak temperature dependence of its viscosity. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Retention modeling in combined pH/organic solvent gradient reversed-phase HPLC.

    Science.gov (United States)

    Zisi, Ch; Fasoula, S; Nikitas, P; Pappa-Louisi, A

    2013-07-07

    An approach for retention modeling of double pH/organic solvent gradient data easily generated by automatically mixing two mobile phases with different pH and organic content according to a linear pump program is proposed. This approach is based on retention models arising from the evaluation of the retention data of a set of 17 OPA derivatives of amino acids obtained in 27 combined pH/organic solvent gradient runs performed between fixed initial pH/organic modifier values but different final ones and for different gradient duration. The derived general model is a ninth parameter equation easily manageable through a linear least-squares fitting but it requires eighteen initial pH/organic modifier gradient experiments for a satisfactory retention prediction in various double gradients of the same kind with those used in the fitting procedure. Two simplified versions of the general model, which were parameterized based on six only initial pH/organic modifier gradients, were also proposed, when one of the final double gradient conditions, pH or organic content was kept constant. The full and the simplified models allowed us to predict the experimental retention data in simultaneous pH/organic solvent double gradient mode very satisfactorily without the solution of the fundamental equation of gradient elution.

  18. Thermal decomposition of organic solvent with nitric acid in nuclear fuel reprocessing plants

    Energy Technology Data Exchange (ETDEWEB)

    Koike, Tadao; Nishio, Gunji; Takada, Junichi; Tukamoto, Michio; Watanabe, Kouji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Miyata, Sadaichirou

    1995-02-01

    Since a thermal decomposition of organic solvent containing TBP (tributyl phosphate) with nitric acid and heavy metal nitrates is an exothermic reaction, it is possible to cause an explosive decomposition of TBP-complex materials formed by a nitration between the solvent and nitric acid, if the solvent involving TBP-complex is heated upto a thermal limit in an evaporator to concentrate a fuel liquid solution from the extraction process in the reprocessing plant. In JAERI, the demonstration test for explosive decomposition of TBP-complex by the nitration was performed to elucidate the safety margin of the evaporator in the event of hypothetical explosion under auspices of the Science and Technology Agency. The demonstration test was carried out by heating TBP/n-dodecane solvent mixed with nitric acid and uranium nitrate. In the test, the thermal decomposition behavior of the solvent was examined, and also a kinematic reaction constant and a heat formation of the TBP-complex decomposition were measured by the test. In the paper, a safety analysis of a model evaporator was conducted during accidental conditions under the explosive decomposition of the solvent. (author).

  19. Separation of Acetic Acid from Aqueous Solution using Various Organic Solvents

    Directory of Open Access Journals (Sweden)

    Md. Zaved Hossain Khan

    2014-01-01

    Full Text Available 800x600 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 In the study a model has been developed to separate the acetic acid from aqueous solution by liquid-liquid extraction and find out the proper solvent for this separation. Various solvents such as n-butanol, iso butanol, amyl alcohol and ethyl acetate are used for separation of acetic acid from water. The binodal curves (mutual solubility curves for acetic acid distributed between water and an organic solvent were obtained by titrating known mixtures of two components (water and solvents with the third component acetic acid to the point of first appearance of permanent turbidity. In order to determine the tie-lines, the absorbance of the coexisting phases, obtained by the separation of ternary mixtures within the binodal curve are needed to be determined. The absorbance of each point had been determined by a UV spectrophotometer. Distribution diagrams are obtained by plotting weight percent of acetic acid in solvent phase against the weight percent of acetic acid in water phase. Selectivity diagrams are also obtained by plotting (wt. % of acetic acid / (percent of acetic acid + percent of water in solvent phase against the same quantity in the diluent phase. The separation factor is determined numerically from the tie-line data.

  20. Micellization of alkyl-propoxy-ethoxylate surfactants in water-polar organic solvent mixtures.

    Science.gov (United States)

    Sarkar, Biswajit; Lam, Stephanie; Alexandridis, Paschalis

    2010-07-06

    The effects of cosolvents (glycerol, ethanol, and isopropanol) on the self-assembly of novel alkyl-propoxy-ethoxylate surfactants in aqueous solutions have been investigated with a focus on the (i) quantification of solvent effects on the critical micelle concentration (cmc), (ii) free-energy contributions to micellization, (iii) local environment in the micellar solution, and (iv) structure of the micelles. The introduction of the polar organic solvents considered in this work into water decreases cohesive forces in the solvent mixture, resulting in an increase in the solubility of the surfactant molecules. As a result, micelle formation becomes less favorable and the cmc increases. The contribution of the cosolvent to the free energy of micellization is positive, and the data for different mixed solvents collapse onto a single straight line when plotted versus a function of the solubility parameters of the surfactant alkyl chains and the mixed solvents. The behavior of the poly(propylene oxide) part of the alkyl-propoxy-ethoxylate surfactants is hydrophilic, albeit less so in the ethanol-water mixed solvent than in plain water. Pyrene fluorescence emission I(1)/I(3) data suggest that the microenvironment in micellar solutions is affected mainly by the cosolvent concentration, not the surfactant degree of ethoxylation. Small-angle X-ray scattering data for both water and ethanol-water surfactant solutions are consistent with oblate ellipsoid micelles and reveal that the introduction of 20% ethanol decreases the micelle long axis by 10-15%.

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

    Indian Academy of Sciences (India)

    Sanjog S Nagarkar; Sujit K Ghosh

    2015-04-01

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

  2. Random mutagenesis and selection of organic solvent-stable haloperoxidase from Streptomyces aureofaciens.

    Science.gov (United States)

    Yamada, Ryosuke; Higo, Tatsutoshi; Yoshikawa, Chisa; China, Hideyasu; Yasuda, Masahiro; Ogino, Hiroyasu

    2015-01-01

    Haloperoxidases are useful oxygenases involved in halogenation of a range of water-insoluble organic compounds and can be used without additional high-cost cofactors. In particular, organic solvent-stable haloperoxidases are desirable for enzymatic halogenations in the presence of organic solvents. In this study, we adopted a directed evolution approach by error-prone polymerase chain reaction to improve the organic solvent-stability of the homodimeric BPO-A1 haloperoxidase from Streptomyces aureofaciens. Among 1,000 mutant BPO-A1 haloperoxidases, an organic solvent-stable mutant OST48 with P123L and P241A mutations and a high active mutant OST959 with H53Y and G162R mutations were selected. The residual activity of mutant OST48 after incubation in 40% (v/v) 1-propanol for 1 h was 1.8-fold higher than that of wild-type BPO-A1. In addition, the OST48 mutant showed higher stability in methanol, ethanol, dimethyl sulfoxide, and N,N-dimethylformamide than wild-type BPO-A1 haloperoxidase. Moreover, after incubation at 80°C for 1 h, the residual activity of mutant OST959 was 4.6-fold higher than that of wild-type BPO-A1. Based on the evaluation of single amino acid-substituted mutant models, stabilization of the hydrophobic core derived from P123L mutation and increased numbers of hydrogen bonds derived from G162R mutation led to higher organic solvent-stability and thermostability, respectively.

  3. [Investigation on low power microwave irradiation-assisted enzymatic esterification in organic solvent by fluorescence spectroscopy].

    Science.gov (United States)

    Min, Rui; Fang, Yun; Xia, Yong-Mei

    2009-02-01

    The authors studied the fluorescence change of immobilized lipase from Rhizomucor miehei in the microwave assisted enzymatic esterification of caprylic acid and butanol in organic medium by investigating the fluorescence spectra in solvent or aqueous buffer after incubating the lipase with the solvent, caprylic acid and butanol under microwave irradiation, respectively. A comparison was made with the conventional heated enzymatic esterification in the solvents. Both of the heating modes, the microwave irradiation and conventional heating, can enhance the fluorescence intensity without shifting the emission wavelength of the lipase. In the circumstance that the irradiation can accelerate the esterification, the irradiation can enhance the exposure of the lipase protein molecules in the aqueous environment after incubating the lipase with solvents or the substrates. The effect of the reaction mixture on the fluorescence intensity was dominated by the solvents. The trend of the plot of log P versus the initial reaction rate was similar to that of log P versus fluorescence intensity of lipase in aqueous buffer after esterification; but was different from that of log P versus fluorescence intensity of lipase in organic medium.

  4. Impact Of Organic Solvents And Common Anions On 2-Chlorobiphenyl Dechlorination Kinetics With Pd/Mg

    Science.gov (United States)

    The current study evaluates Pd/Mg performance for 2-chlorobiphenyl (2-CB) dechlorination in the presence of naturally abundant anions such as sulfate, chloride, nitrate, hydroxide and carbonates and organic solvents that are used for ex-situ PCB extraction or may accompany PCB co...

  5. Adverse reproductive outcomes among male painters with occupational exposure to organic solvents.

    NARCIS (Netherlands)

    Hooiveld, M.; Haveman, W.; Roskes, K.; Bretveld, R.W.; Burstyn, I.; Roeleveld, N.

    2006-01-01

    OBJECTIVES: To assess the risks of reproductive disorders and birth defects in offspring of male painters with exposure to organic solvents, and to determine the shape of the dose-response relationship. METHODS: Random samples of painters and carpenters were drawn from workers affiliated with the

  6. "Chemistry in a spinneret" to fabricate hollow fibers for organic solvent filtration

    NARCIS (Netherlands)

    Dutczak, S.M.; Tanardi, Cheryl; Kopec, K.K.; Wessling, Matthias; Stamatialis, Dimitrios

    2012-01-01

    Organic solvent filtration (OSF) is a very efficient separation technique with high potential in many branches of industry. Currently the choice of the commercial membranes is limited only to a few flat sheet membranes and spiral wound modules. It is generally known that a membrane in hollow fiber

  7. Aggregation behavior of cholic acid derivatives in organic solvents and in water

    NARCIS (Netherlands)

    Willemen, H.M.

    2002-01-01

    In this thesis various cholic acid derivatives are reported that display aggregation in water or in organic solvents. Spontaneous aggregation of single molecules into larger, ordered structures occurs at the borderline of solubility. Amphiphilic compounds, or surfactants, which possess a hydrophobic

  8. Poly(L-aspartic acid) derivative soluble in a volatile organic solvent for biomedical application.

    Science.gov (United States)

    Oh, Nam Muk; Oh, Kyung Taek; Youn, Yu Seok; Lee, Eun Seong

    2012-09-01

    In order to develop a novel functional poly(L-amino acid) that can dissolve in volatile organic solvents, we prepared poly[L-aspartic acid-g-(3-diethylaminopropyl)]-b-poly(ethylene glycol) [poly(L-Asp-g-DEAP)-b-PEG] via the conjugation of 3-diethylaminopropyl (DEAP) to carboxylate groups of poly(L-Asp) (M(n) 4 K)-b-PEG (M(n) 2 K). This poly(L-aspartic acid) derivative evidenced a relatively high solubility in volatile organic solvents such as dichloromethane, chloroform, and acetone. We fabricated a model nanostructure (i.e., polymeric micelle) using poly(L-Asp-g-DEAP)-b-PEG by the film rehydration method, which involves the simple removal of the volatile organic solvent (dichloromethane) used to dissolve polymer, reducing concerns about organic solvents remaining in a nano-sized particle. Interestingly, this micelle showed the pH-stimulated release of encapsulated model drug [i.e., doxorubicin (DOX)] due to the protonation of DEAP according to the pH of the solution. We expect that this poly(L-aspartic acid) derivative promises to provide pharmaceutical potential for constituting a new stimuli-sensitive drug carrier for various drug molecules.

  9. Preparation of PLA and PLGA nanoparticles by binary organic solvent diffusion method

    Institute of Scientific and Technical Information of China (English)

    蒋新宇; 周春山; 唐课文

    2003-01-01

    The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereevaluated. The yield of nanoparticles prepared by this method is over 90%, and the average size of the nanoparticlesis between 130-180 nm. In order to clarify the effect of the organic solvent used in the system on nanoparticle yieldand size, the cloud points of PLA and PLGA were examined by cloud point titration. The results indicate that theyields of nanoparticles increase with the increase of ethanol in the acetone solution and attain the maximum at thecloud point of ethanol, while the size of nanoparticles decreases with the increase of ethanol in the acetone solutionand attains the minimum at the cloud point of ethanol. The optimal composition ratio of binary organic solvents coin-cides to that near the cloud point and the optimal condition of binary organic solvents can be predicted.

  10. Aggregation behavior modulation of 1-dodecyl-3-methylimidazolium bromide by organic solvents in aqueous solution.

    Science.gov (United States)

    Wang, Jianji; Zhang, Lamei; Wang, Huiyong; Wu, Changzeng

    2011-05-05

    Material preparation in ionic liquids and environmental pollution control by ionic liquids are often closely dependent on the aggregation behavior of ionic liquids in solution. In the present work, conductivity, fluorescence probe, and dynamic light scattering techniques have been used to study the effect of organic solvents on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide in water. It was shown that the critical aggregation concentration (CAC), the ionization degree of the aggregates (α), and the standard Gibbs energy of aggregation (ΔG(m)°) of the ionic liquid increase, while its aggregation number (N(agg)) and aggregates' size decrease with increasing concentration of organic additives in water. These results have been discussed from the favorable interactions of alkyl chain of the ionic liquid with the mixed solvents. It is suggested that the solvophobic parameter, characterized quantitatively by Gibbs energy of transfer of hydrocarbon from gas into a given solvent, can be used to account for the effect of organic additives on the formation and growth of the ionic liquid aggregates in water. Aggregation behavior of ionic liquids in aqueous organic solutions can be modulated simply by the solvophobic parameters of hydrocarbon in the mixed solvents.

  11. Interactions of nonprotic organic solvents with [val5]angiotensin in water.

    Science.gov (United States)

    Neuman, Robert C; Gerig, John T

    2011-02-24

    Intermolecular solvent-solute nuclear Overhauser effects have been used to explore interactions of the organic component of acetonitrile-water, acetone-water, and dimethyl sulfoxide-water mixtures with the peptide hormone [val(5)]angiotensin. As reported by the NOEs, many cross relaxation terms for interactions of these organic cosolvents are adequately accounted for using a hard spheres interaction model in which encounters of peptide and cosolvent molecules take place by mutual diffusion. However, there are indications of localized solvent-peptide interactions that are not well described by this model. In dimethyl sulfoxide-water at 0 °C, organic solvent near the C-terminal Phe8 residue and the Val3 residue produce strongly enhanced cross-relaxation terms. NOEs for all peptide N-H protons and the protons of the Tyr4 aromatic ring were significantly more positive than expected in 33% acetone-water (v/v) at 0 °C, while those for most side-chain protons were close to predictions of the hard sphere model. All peptide-organic solvent NOEs in 35% acetonitrile water (v/v) at 0 °C are consistent with the hard spheres interaction model.

  12. Cochlear condition and olivocochlear system of gas station attendants exposed to organic solvents

    Directory of Open Access Journals (Sweden)

    Tochetto, Tania Maria

    2012-01-01

    Full Text Available Introduction: Organic solvents have been increasingly studied due to its ototoxic action. Objective: Evaluate the conditions of outer hair cells and olivocochlear system in individuals exposed to organic solvents. Method: This is a prospective study. 78 gas station attendants exposed to organic solvents had been evaluated from three gas stations from Santa Maria city, Rio Grande do Sul (RS. After applying the inclusion criteria, the sample was constituted by 24 individuals. The procedures used on the evaluation were audiological anamnesis, Transient otoacoustic emissions (TEOAES and research for the suppressive effect of TEOAES. A group control (GC compounded by 23 individuals was compared to individuals exposed and non-exposed individuals. The data collection has been done in the room of Speech Therapy of Workers Health Reference Center of Santa Maria. Results: The TEOAES presence was major in the left ear in both groups; the average relation of TEOAES signal/noise in both ears was greater in GE; the TEOAES suppressive effect in the right ear was higher in the individual of GE (62,5% and in the left ear was superior in GC (86,96%, with statistically significant difference. The median sign/noise ratio of TEOAES, according to the frequency range, it was higher in GC in three frequencies ranges in the right ear and one in the left ear. Conclusion: It was not found signs of alteration on the outer hair cells neither on the olivocochlear medial system in the individuals exposed to organic solvents.

  13. Understanding mechanisms of asphaltene adsorption from organic solvent on mica.

    Science.gov (United States)

    Natarajan, Anand; Kuznicki, Natalie; Harbottle, David; Masliyah, Jacob; Zeng, Hongbo; Xu, Zhenghe

    2014-08-12

    The adsorption process of asphaltene onto molecularly smooth mica surfaces from toluene solutions of various concentrations (0.01-1 wt %) was studied using a surface forces apparatus (SFA). Adsorption of asphaltenes onto mica was found to be highly dependent on adsorption time and asphaltene concentration of the solution. The adsorption of asphaltenes led to an attractive bridging force between the mica surfaces in asphaltene solution. The adsorption process was identified as being controlled by the diffusion of asphaltenes from the bulk solution to the mica surface with a diffusion coefficient on the order of 10(-10) m(2)/s at room temperature, depending on the asphaltene bulk concentration. This diffusion coefficient corresponds to a hydrodynamic molecular radius of approximately 0.5 nm, indicating that asphaltene diffuses to mica surfaces as individual molecules at very low concentration (e.g., 0.01 wt %). Atomic force microscopy images of the adsorbed asphaltenes on mica support the results of the SFA force measurements. The results from the SFA force measurements provide valuable insights into the molecular interactions (e.g., steric repulsion and bridging attraction as a function of distance) of asphaltenes in organic media and hence their roles in crude oil and bitumen production.

  14. Effect of Mixed Solvents Consisting of Water and Organic Solvent on Preparation of Medium-Responsive Grafted Cellulose Film by Means of Photografting

    Directory of Open Access Journals (Sweden)

    Irwan Ginting-Suka

    2006-11-01

    Full Text Available Cellulose having a medium-responsive function were synthesized by photografting of methacrylic acid (MAA on regenerated cellulose film (thickness = 20 µm at 60°C using mixed solvent consisting of water and organic solvents such as acetone and methanol. Xanthone was used as photoinitiator by coating on the film surfaces. A maximum percentage of grafting was observed at a certain concentration of organic solvent. MAA-grafted cellulose films produced showing homogeneous distribution of grafted chains, which was examined by scanning electron microscopy. The modified films also exhibit medium responsive character, it shrinks in acidic and swells in basic solution. Moreover, the grafted film exhibited the ability to absorb copper ion, which was not influenced by the solvent used in grafting processes.

  15. Dispersion of Multiwall Carbon Nanotubes in Organic Solvents through Hydrothermal Supercritical Condition

    Directory of Open Access Journals (Sweden)

    Krishnegowda Jagadish

    2015-01-01

    Full Text Available Multiwall carbon nanotube (MWCNT composite materials require careful formulation of processing methods to ultimately realize the desired properties. Until now, controlled dispersion of MWCNT remains a challenge, due to strong van der Waals binding energies associated with the MWCNT aggregates. In the present study, an effort has been made to disperse MWCNTs in organic solvents like dichloromethane, ethanol, isopropyl alcohol, and hexane through hydrothermal reaction. Dichloromethane is considered the best solvent for the dispersion of MWCNTs. The characterizations were carried out to find the dispersion design, particle size, and stabilization, which clearly indicate that the desired properties of MWCNTs have been achieved.

  16. Anticomplement activity of organic solvent extracts from Korea local Amarantaceae spp.

    Science.gov (United States)

    Jung, Seil; Lee, Jai-Heon; Lee, Young-Choon; Moon, Hyung-In

    2012-04-01

    The study evaluated the anticomplement activity from various solvent extracts of nine Amarantaceae plants (Achyranthes japonica (Miq.) Nakai, Amaranthus mangostanus L., Amaranthus retroflexus L., Amaranthus spinosus L., Celosia argentea var. spicata., Amaranthus lividus L., Celosia cristata L., Amaranthus viridis L., Gomphrena globosa L.) from South Korea on the classical pathway. We have evaluated various organic solvent extract from nine Amarantaceae plants with regard to its anticomplement activity on the classical pathway. Achyranthes japonica chloroform extracts showed inhibitory activity against complement system with 50% inhibitory concentrations (IC(50)) value of 73.1μg/ml. This is the first report of anticomplement activity from Amarantaceae plants.

  17. Morphology versus Vertical Phase Segregation in Solvent Annealed Small Molecule Bulk Heterojunction Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Alexander Kovalenko

    2015-01-01

    Full Text Available The deep study of solvent annealed small molecules bulk heterojunction organic solar cells based on DPP(TBFu2 : PC60BM blend is carried out. To reveal the reason of the solvent annealing advantage over the thermal one, capacitance-voltage measurements were applied. It was found that controlling the vertical phase segregation in the solar cells a high fullerene population in the vicinity of the cathode could be achieved. This results in increase of the shunt resistance of the cell, thus improving the light harvesting efficiency.

  18. Substitution of Organic Solvents - a Way to improve Working Environment and reduce Emissions to the Atmosphere

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    1996-01-01

    the process in order to omit the solvents or to use water-based products. In cases, where a change to water-based is not evident, improvements can be reached by using non-volatile, low-toxic products, typically esters of fatty acids from vegetable oils. In offset printing a drastic reduction of use of organic...... solvents as cleaning agents has been reached. However, some barriers to this substitution process, are found outside the printing companies. In designing of machines and auxiliary equipment, the manufacturers must take into account, that cleaning with non-volatile agents should be possible. Even a rather...

  19. Mass transfer coefficient of slug flow for organic solvent-aqueous system in a microreactor

    Energy Technology Data Exchange (ETDEWEB)

    Tuek, Ana Jurinjak; Anic, Iva; Kurtanjek, Zelimir; Zelic, Bruno [University of Zagreb, Zagreb (Croatia)

    2015-06-15

    Application of microreactor systems could be the next break-through in the intensification of chemical and biochemical processes. The common flow regime for organic solvent-aqueous phase two-phase systems is a segmented flow. Internal circulations in segments cause high mass transfer and conversion. We analyzed slug flow in seven systems of organic solvents and aqueous phase. To analyze how slug lengths in tested systems depend on linear velocity and physical and chemical properties of used organic solvents, regression models were proposed. It was shown that models based on linearization of approximation by potentials give low correlation for slug length prediction; however, application of an essential nonlinear model of multiple layer perception (MLP) neural network gives high correlation with R{sup 2}=0.9. General sensitivity analysis was applied for the MLP neural network model, which showed that 80% of variance in slug length for the both phases is accounted for the viscosity and density of the organic phases; 10% is accounted by surface tension of the organic phase, while molecular masses and flow rates each account for 5%. For defined geometry of microreactor, mass transfer has been determined by carrying out the neutralization experiment with NaOH where acetic acid diffuses from organic phase (hexane) into aqueous phase. Estimated mass transfer coefficients were in the range k{sub L}a=4,652-1,9807 h{sup -1}.

  20. Determination of physical properties for the mixtures of [BMIM]Cl with different organic solvents

    Institute of Scientific and Technical Information of China (English)

    Hina Saba; Xinjun Zhu; Ye Chen; Yumei Zhang

    2015-01-01

    Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of 1-butyl-3-methyl imidazolium chloride ([BMIM]Cl) and different organic solvents at 298.15 K have been investigated. Ex-cess molar volumes have been calculated and obtained data has been fitted by the Redlich–Kister equation. The density and refractive index were found to increase with increasing concentration of [BMIM]Cl, however, excep-tions do exist as in the case of dimethyl sulfoxide (DMSO)/[BMIM]Cl. For DMSO/[BMIM]Cl, the density decreases with increasing concentration. The addition of different organic solvents was able to disrupt the interactions within mixtures, leading to free mobility of ions. The free mobility of ions has been found to enhance conductivity and decrease viscosity to varying extents in al mixtures studied. It has been observed that solubility parameters, dielectric constants and composition of the solvents used play a vital role in determining the resultant properties. The data obtained wil play an important role in understanding the effect of the addition of organic solvents in ILs to enhance their applicability.

  1. Lignin Peroxidase Oxidation of Aromatic Compounds in Systems Containing Organic Solvents

    Science.gov (United States)

    Vazquez-Duhalt, Rafael; Westlake, Donald W. S.; Fedorak, Phillip M.

    1994-01-01

    Lignin peroxidase from Phanerochaete chrysosporium was used to study the oxidation of aromatic compounds, including polycyclic aromatic hydrocarbons and heterocyclic compounds, that are models of moieties of asphaltene molecules. The oxidations were done in systems containing water-miscible organic solvents, including methanol, isopropanol, N, N-dimethylformamide, acetonitrile, and tetrahydrofuran. Of the 20 aromatic compounds tested, 9 were oxidized by lignin peroxidase in the presence of hydrogen peroxide. These included anthracene, 1-, 2-, and 9-methylanthracenes, acenaphthene, fluoranthene, pyrene, carbazole, and dibenzothiophene. Of the compounds studied, lignin peroxidase was able to oxidize those with ionization potentials of <8 eV (measured by electron impact). The reaction products contain hydroxyl and keto groups. In one case, carbon-carbon bond cleavage, yielding anthraquinone from 9-methylanthracene, was detected. Kinetic constants and stability characteristics of lignin peroxidase were determined by using pyrene as the substrate in systems containing different amounts of organic solvent. Benzyl alkylation of lignin peroxidase improved its activity in a system containing water-miscible organic solvent but did not increase its resistance to inactivation at high solvent concentrations. PMID:16349176

  2. Solvent dependence of Stokes shift for organic solute-solvent systems: A comparative study by spectroscopy and reference interaction-site model-self-consistent-field theory.

    Science.gov (United States)

    Nishiyama, Katsura; Watanabe, Yasuhiro; Yoshida, Norio; Hirata, Fumio

    2013-09-01

    The Stokes shift magnitudes for coumarin 153 (C153) in 13 organic solvents with various polarities have been determined by means of steady-state spectroscopy and reference interaction-site model-self-consistent-field (RISM-SCF) theory. RISM-SCF calculations have reproduced experimental results fairly well, including individual solvent characteristics. It is empirically known that in some solvents, larger Stokes shift magnitudes are detected than anticipated on the basis of the solvent relative permittivity, ɛr. In practice, 1,4-dioxane (ɛr = 2.21) provides almost identical Stokes shift magnitudes to that of tetrahydrofuran (THF, ɛr = 7.58), for C153 and other typical organic solutes. In this work, RISM-SCF theory has been used to estimate the energetics of C153-solvent systems involved in the absorption and fluorescence processes. The Stokes shift magnitudes estimated by RISM-SCF theory are ∼5 kJ mol(-1) (400 cm(-1)) less than those determined by spectroscopy; however, the results obtained are still adequate for dipole moment comparisons, in a qualitative sense. We have also calculated the solute-solvent site-site radial distributions by this theory. It is shown that solvation structures with respect to the C-O-C framework, which is common to dioxane and THF, in the near vicinity (∼0.4 nm) of specific solute sites can largely account for their similar Stokes shift magnitudes. In previous works, such solute-solvent short-range interactions have been explained in terms of the higher-order multipole moments of the solvents. Our present study shows that along with the short-range interactions that contribute most significantly to the energetics, long-range electrostatic interactions are also important. Such long-range interactions are effective up to 2 nm from the solute site, as in the case of a typical polar solvent, acetonitrile.

  3. 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.

  4. Expanded Porphyrin-Anion Supramolecular Assemblies: Environmentally Responsive Sensors for Organic Solvents and Anions.

    Science.gov (United States)

    Zhang, Zhan; Kim, Dong Sub; Lin, Chung-Yon; Zhang, Huacheng; Lammer, Aaron D; Lynch, Vincent M; Popov, Ilya; Miljanić, Ognjen Š; Anslyn, Eric V; Sessler, Jonathan L

    2015-06-24

    Porphyrins have been used frequently to construct supramolecular assemblies. In contrast, noncovalent ensembles derived from expanded porphyrins, larger congeners of naturally occurring tetrapyrrole macrocycles, are all but unknown. Here we report a series of expanded porphyrin-anion supramolecular assemblies. These systems display unique environmentally responsive behavior. Addition of polar organic solvents or common anions to the ensembles leads to either a visible color change, a change in the fluorescence emission features, or differences in solubility. The actual response, which could be followed easily by the naked eye, was found to depend on the specifics of the assembly, as well as the choice of analyte. Using the ensembles of this study, it proved possible to differentiate between common solvents, such as diethyl ether, THF, ethyl acetate, acetone, alcohol, acetonitrile, DMF, and DMSO, identify complex solvent systems, as well as distinguish between the fluoride, chloride, bromide, nitrate, and sulfate anions.

  5. Anomalous Capacitance Maximum of the Glassy Carbon-Ionic Liquid Interface through Dilution with Organic Solvents.

    Science.gov (United States)

    Bozym, David J; Uralcan, Betül; Limmer, David T; Pope, Michael A; Szamreta, Nicholas J; Debenedetti, Pablo G; Aksay, Ilhan A

    2015-07-02

    We use electrochemical impedance spectroscopy to measure the effect of diluting a hydrophobic room temperature ionic liquid with miscible organic solvents on the differential capacitance of the glassy carbon-electrolyte interface. We show that the minimum differential capacitance increases with dilution and reaches a maximum value at ionic liquid contents near 5-10 mol% (i.e., ∼1 M). We provide evidence that mixtures with 1,2-dichloroethane, a low-dielectric constant solvent, yield the largest gains in capacitance near the open circuit potential when compared against two traditional solvents, acetonitrile and propylene carbonate. To provide a fundamental basis for these observations, we use a coarse-grained model to relate structural variations at the double layer to the occurrence of the maximum. Our results reveal the potential for the enhancement of double-layer capacitance through dilution.

  6. An Optical Tweezers Platform for Single Molecule Force Spectroscopy in Organic Solvents.

    Science.gov (United States)

    Black, Jacob; Kamenetska, Maria; Ganim, Ziad

    2017-10-03

    Observation at the single molecule level has been a revolutionary tool for molecular biophysics and materials science, but single molecule studies of solution-phase chemistry are less widespread. In this work we develop an experimental platform for solution-phase single molecule force spectroscopy in organic solvents. This optical-tweezer-based platform was designed for broad chemical applicability and utilizes optically trapped core-shell microspheres, synthetic polymer tethers, and click chemistry linkages formed in situ. We have observed stable optical trapping of the core-shell microspheres in ten different solvents, and single molecule link formation in four different solvents. These experiments demonstrate how to use optical tweezers for single molecule force application in the study of solution-phase chemistry.

  7. [Determination of residual organic solvents in flunixin meglumine raw material by headspace gas chromatography].

    Science.gov (United States)

    Hu, Huilian

    2012-01-01

    A method for the determination of five kinds of residual organic solvents in flunixin meglumine raw material was developed by headspace gas chromatography. An HP-FFAP capillary column (30 m x 0.32 mm x 1.0 microm), a flame ionization detector and the external standard method were used for the separation and quantitative analysis. The effects of equilibrium temperature and equilibrium time on the determination of residual organic solvents were investigated. The good results were obtained in the equilibrium temperature of 90 degrees C and equilibrium time of 30 min. The standard curves were linear in the range of 0.40-7.93 mg/L (r = 0.999 8) for ethyl acetate, 7.32-146.48 mg/L (r = 0.999 6) for methanol, 4.53-90.61 mg/L (r = 0.999 9) for isopropanol, 3.62-72.32 mg/L (r = 0.999 8) for ethanol and 2.31-46.24 mg/L (r = 0.999 6) for acetonitrile. The recoveries for the five residual organic solvents were between 95.96% and 100.31% with relative standard deviations (RSDs) (n = 6) of 1.97%-3.28%. The detection limits of ethyl acetate, methanol, isopropanol, ethanol and acetonitrile were 0.08, 0.9, 0.2, 0.4 and 0.3 mg/L, respectively. The proposed method was successfully applied to analyze the residual organic solvents in the real sample of flunixin meglumine raw material. The results showed that only isopropanol and ethanol were found in the sample with the contents of 177.44 microg/g and 69.32 microg/g, respectively. The method is rapid, sensitive and accurate for the content determination of residual solvents in flunixin meglumine raw material.

  8. [Adsorption and desorption of organic solvent vapours using silica gel (author's transl)].

    Science.gov (United States)

    Takata, T; Aoki, B

    1981-01-01

    For a simple analysis of organic solvent vapours in working environmental air, we investigated the following method. First, join the adsorption tube (2 ml of 60--80 mesh silica gel packed in a 5 mm phi x 18 cm glass tube) to hand vacuum pump and suck 200 ml of the sample air. After adsorption, join this adsorption tube to the sampling bottle under reduced pressure. Second, open the cock of the sampling bottle and heat only the adsorption tube in an oven for 3 min. In the operation mentioned above, organic solvent vapours desorbed from the silica gel transfer smoothly into the sampling bottle. After desorption, take 1 ml of air from the sampling bottle and determine the sample quantities with the gas chromatograph. Sample solvents used were as follows: n-hexane, cyclohexane, benzene, toluene, m-xylene, styrene, 1.1.1-trichloroethane, dichloromethane, tetrachloroethylene, ethylacetate, acetone, methyl-ethylketone, methylisobutylketone, methanol, ethanol, n-propanol, and n-butanol. We obtained the following results. (1) 60--80 mesh silica gel is appropriate for this method. (2) Heating temperature to get 100% recovery varies with the type of organic solvent. m-Xylene and styrene require 250 degrees C, methylisobutylketone and n-butanol 200 degrees C, and the others 150 degrees C. (3) If the adsorption tube is preserved in a freezer at -20 degrees C, no decrease is observed for up to 7 days. At room temperatures, however, 1.1.1-trichloroethane, dichloromethane, tetrachloroethylene, n-hexane, and cyclohexane decreased by the amount 4-10% in the tube for each 24-hour period. These sample should be preserved at lower temperatures soon after absorbing on the silica gel. This method is simple and accurate, so valid for analysis of organic solvent vapours in the working environmental air.

  9. [Development of revolutionary enzymatic reactions in organic solvents with molecular display].

    Science.gov (United States)

    Ueda, Mitsuyoshi

    2010-11-01

    We have seen increasing use of the term "White biotechnology". White biotechnology involves the use of microbial cells and enzymes in the production of bulk and fine chemicals such as amino acids and polymers. This generally results in cleaner processes with minimum waste generation and energy use. Most of the organic syntheses using enzymes are carried out in nearly anhydrous organic solvents or solvent-free media. Ionic liquids have more recently emerged as another nonaqueous media, which, in view of their low vapor pressure, are viewed as "green solvents". Organic solvents may alter the structure and activity of enzymes that usually function in an aqueous environment. One alternative is to immobilize the enzymes on solid supports to increase their function and stability in response to organic solvents or increased temperatures. Enzymes may be stabilized by chemical and physical processes. With chemical methods, enzymes are immobilized by strong covalent bonding, but changes in protein structure often result. In physical stabilization processes, the interactions between enzymes and solids usually are weaker, resulting in fewer changes in the enzyme's structure. Yeast cell surface engineering is an alternative approach that immobilizes enzymes on the yeast cell surface. Proteins are immobilized by using an outer shell cell-wall protein, the C-terminal half of alpha-agglutinin. Display of enzymes on the yeast cell surface has at least two advantages relative to other physical immobilization methods. First, the displayed enzymes can be readily produced in a standard fermentation. No further work is required to either purify or immobilize the enzymes. Second, enzyme displayed on the yeast cell surface can be modified directly by conventional genetic engineering, which enables error-prone PCR, DNA shuffling, and combinatorial mutagenesis to be used quickly and efficiently to create strains (whole-cell biocatalysts) with enhanced enzyme activity.

  10. Hydrogen/deuterium exchange study of subtilisin Carlsberg during prolonged exposure to organic solvents.

    Science.gov (United States)

    Fasoli, Ezio; Ferrer, Amaris; Barletta, Gabriel L

    2009-03-01

    It has been previously reported that prolonged exposure of an enzyme to organic solvents leads to substantial decrease of activity. This effect was found to be unrelated to the catalysts' structure or their possible aggregation in organic solvents, and up to the present day the cause for activity loss remains unclear. In the present work, the structural dynamics of the serine protease subtilisin Carlsberg (SC) have been investigated during prolonged exposure to two organic solvents by following hydrogen/deuterium (H/D) exchange of mobile protons. The enzyme, after lyophilization, was incubated in organic solvents at controlled deuteriated water activity for different times and the H/D exchange was allowed to take place. The amount of deuterium exchanged was evaluated by (2)H NMR, which in turn gave us a picture of the changing dynamics of our model enzyme during incubation and under different experimental conditions. Our results show that the flexibility of SC decreases during prolonged storage in 1,4-dioxane (Diox) and acetonitrile (ACN) as indicated by the observed 3- to 10-fold decrease in the apparent rate constants of exchange (k) of fast exchangeable protons (FEP) and slow exchangeable protons (SEP) in the protein. Our study also shows that SC is more flexible in ACN than in Diox (k 3-20 times higher in ACN for the FEP and SEP), suggesting that enzyme dynamics are affected by solvent physicochemical properties. Additionally, the enzyme dynamics are also affected by the method of preparation: decreased flexibility (k decreases 3- to 10-fold for FEP and SEP) is observed when the enzyme is chemically modified with poly ethylene glycol (PEGylated) or colyophilized with crown ethers. A possible relationship between activity, enantioselectivity (E), and structural dynamics is discussed, demonstrating that direct correlations, as have been attempted in the past, are hampered by the multi-variable nature and complexity of the system.

  11. Crystal structure, optical and thermal studies of a new organic nonlinear optical material: L-Histidinium maleate 1.5-hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Gonsago, C. Alosious [Department of Physics, A. J. College of Engineering, Chennai 603103 (India); Albert, Helen Merina [Department of Physics, Sathyabama University, Chennai 600119 (India); Karthikeyan, J. [Department of Chemistry, Sathyabama University, Chennai 600119 (India); Sagayaraj, P. [Department of Physics, Loyola College, Chennai 600034 (India); Pragasam, A. Joseph Arul, E-mail: drjosephsu@gmail.com [Department of Physics, Sathyabama University, Chennai 600119 (India)

    2012-07-15

    Highlights: ► L-Histidinium maleate 1.5-hydrate, a new organic crystal has been grown for the first time. ► The crystal structure is reported for the first time (CCDC 845975). ► The crystal belongs to monoclinic system with space group P2{sub 1}, Z = 4, a = 11.4656(7) Å, b = 8.0530(5) Å, c = 14.9705(9) Å and β = 101.657(2)°. ► The optical absorption study substantiates the complete transparency of the crystal. ► Kurtz powder SHG test confirms the nonlinear property of the crystal. -- Abstract: A new organic nonlinear optical material L-histidinium maleate 1.5-hydrate (LHM) with the molecular formula C{sub 10}H{sub 16}N{sub 3}O{sub 7.5} has been successfully synthesized from aqueous solution by slow solvent evaporation method. The structural characterization of the grown crystal was carried out by single crystal X-ray diffraction at 293(2) K. In the crystal, molecules are linked through inter and intramolecular N-H⋯O and O-H⋯O hydrogen bonds, generate edge fused ring motif. The hydrogen bonded motifs are linked to each other to form a three dimensional network. The FT-IR spectroscopy was used to identify the functional groups of the synthesized compound. The optical behavior of the grown crystal was examined by UV–visible spectral analysis, which shows that the optical absorption is almost negligible in the wavelength range 280–1300 nm. The nonlinear optical property was confirmed by the powder technique of Kurtz and Perry. The thermal behavior of the grown crystal was analyzed by thermogravimetric analysis.

  12. Effect of some organic solvent-water mixtures composition on precipitated calcium carbonate in carbonation process

    Science.gov (United States)

    Konopacka-Łyskawa, Donata; Kościelska, Barbara; Karczewski, Jakub

    2015-05-01

    Precipitated calcium carbonate particles were obtained during carbonation of calcium hydroxide slurry with carbon dioxide. Aqueous solutions of isopropyl alcohol, n-butanol and glycerol were used as solvents. Concentration of organic additives in the reactive mixture was from 0% to 20% (vol). Precipitation process were performed in a stirred tank reactor equipped with gas distributor. Multimodal courses of particles size distribution were determined for produced CaCO3 particles. Calcium carbonate as calcite was precipitated in all experiments. The mean Sauter diameter of CaCO3 particles decreased when the concentration of all used organic additives increased. The amount of small particle fraction in the product increased with the increasing concentration of organic solvents. Similar physical properties of used liquid phase resulted in the similar characteristics of obtained particles.

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

    Science.gov (United States)

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

    2015-10-01

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

  14. Cell Hydration as a Biomarker for Estimation of Biological Effects of Nonionizing Radiation on Cells and Organisms

    Directory of Open Access Journals (Sweden)

    Sinerik Ayrapetyan

    2014-01-01

    Full Text Available “Changes in cell hydration” have been hypothesized as an input signal for intracellular metabolic cascade responsible for biological effects of nonionizing radiation (NIR. To test this hypothesis a comparative study on the impacts of different temperature and NIR (infrasound frequency mechanical vibration (MV, static magnetic field (SMF, extremely low frequency electromagnetic field (ELF EMF, and microwave (MW pretreated water on the hydration of barley seeds in its dormant and germination periods was performed. In dormant state temperature sensitivity (Q10 of seed hydration in distilled water (DW was less than 2, and it was nonsensitive to NIR treated DW, whereas during the germination period (48–72 hours seeds hydration exhibited temperature sensitivity Q10>2 and higher sensitivity to NIR treated DW. Obtained data allow us to suggest that the metabolic driving of intracellular water dynamics accompanied by hydrogen bonding and breaking is more sensitive to NIR-induced water structure changes in seed bathing aqua medium than the simple thermodynamic processes such as osmotic gradient driven water absorption by seeds in dormant state. Therefore, cell hydration is suggested to be a universal and extrasensitive biomarker for detection of biological effects of NIR on cells and organisms.

  15. Structure Characterization and Properties of Metal-Surfactant Complexes Dispersed in Organic Solvents.

    Science.gov (United States)

    de la Iglesia, Pablo; Jaeger, Vance W; Xi, Yuyin; Pfaendtner, Jim; Pozzo, Lilo D

    2015-08-25

    This work describes the synthesis and characterization of metal-surfactant complexes. Dioctyl sulfosuccinate and dodecylbenzenesulfonate are associated with multivalent aluminum, iron, and vanadium ions using an ion exchange reaction. The metal complexes are dispersible in various organic solvents. In solvents with low polarity, the complexes form "inverse" macromolecular structures with multiple metal ions. In contrast, in alcohols, the complex size is reduced, showing a more disperse conformation. The metal and surfactant ions are still strongly bonded to each other in all the solvents probed. Small-angle X-ray and neutron scattering (SAXS and SANS) are used to characterize the structures. Simultaneous fitting of neutron and X-ray scattering spectra is performed in order to obtain an accurate description of the system. Scattering results are also validated by performing molecular dynamics (MD) simulations. The conductive and electrochemical properties of the complexes in solution are also evaluated. The dispersion of metal-organic complexes significantly increases electric conductivity, and some metal ions in the core of the complexes are shown to be electrochemically active in apolar solvents.

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Science.gov (United States)

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

    2016-12-01

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

  18. Process and device for hydrating organic compounds which can be hydrated by cathodically separated hydrogen. Verfahren und Vorrichtung zur Hydrierung von hydrierbaren organischen Verbindungen durch kathodisch abgeschiedenen Wasserstoff

    Energy Technology Data Exchange (ETDEWEB)

    Biallas, B.; Schulten, R.; Weirich, W.

    1984-03-29

    Hydratable compounds, particularly alcohols, can be hydrated by cathodically separated hydrogen, by bringing them into contact with the back of the cathode, which is itself permeable to hydrogen. This procedure is particularly suitable for the hydration of methanol by cathodically separated hydrogen during electrolysis of water in the context of a hybrid circuit process for generating hydrogen, together with steam reforming and synthesis of methanol as further parts of the process.

  19. Isolation, identification and characterization of organic solvent tolerant protease from Bacillus sp. DAF-01

    Directory of Open Access Journals (Sweden)

    Arastoo Badoei-Dalfard

    2012-01-01

    Full Text Available Introduction: Organic solvent-tolerant bacteria are relatively novel extermophilic microorganisms, which can produce organic tolerant protease with capacity of being used in industrial biotechnology for producing high-value compounds. Therefore, finding of these bacteria has drawn much researchers attention nowadays. Materials and Methods: In this project, samples were collected from a hot spring, located in Jiroft. Samples were incubated in medium supplemented with cyclohexane and toluene for 3 days. Screening of protease producing bacteria was performed on the specific media, SKM (Skim milk agar, based on clear area diameter. The best bacterium was identified based on 16s rDNA gene. Protease activity was considered in different temperatures, pH and organic solvents.Results: Sequence alignment and phylogenetic tree results showed that this bacteria was closely related to Bacillus niacini, with 97% homology. Enzymatic studies showed that, this enzyme was active at a wide range of temperatures, 20-90 °C and it,s optimal activity was in 60 °C. In addition, maximum protease activity was obtained in the 8-9 range of pH, and optimal stability was also at pH 9.0. Protease activity in the presence of methanol, toluene, isopropanol, cyclohexane and DMF ‏showed that, remaining activity was at least 80% compared to the control (without organic solvent Discussion and Conclusion: Thermopilic capacity, being active in alkaline protease and high protease stability in the presence of organic solvents all herald a remarkable application for using in different industries.

  20. Singlet oxygen-sensitized delayed emissions from hydrogen peroxide/gallic acid/potassium ferricyanide systems containing organic solvents

    Science.gov (United States)

    Ishii, Hiroshi; Tsukino, Kazuo; Sekine, Masahiko; Nakata, Munetaka

    2009-06-01

    Fourier-transform chemiluminescence spectra of H 2O 2/gallic acid/K 3[Fe(CN) 6] systems containing organic solvents were measured. Emission bands with peaks around 530 and 700 nm were observed in systems containing solvents with a carbonyl group such as N, N-dimethylformamide, and those with a hydroxyl group such as methanol, respectively. The relative band intensities depended strongly on the concentration of these organic solvents. The emission species are attributed to gallic acid-ferricyanide complexes excited by energy transfer from singlet oxygen dimol, ( 1O 2) 2. The effects of organic solvents are interpreted in terms of intermolecular interactions of gallic acid-ferricyanide complexes, water molecules and organic solvents.

  1. Effects of organic solvents and substrate binding on trypsin in acetonitrile and hexane media.

    Science.gov (United States)

    Meng, Yanyan; Yuan, Yuan; Zhu, Yanyan; Guo, Yanzhi; Li, Menglong; Wang, Zhimeng; Pu, Xuemei; Jiang, Lin

    2013-09-01

    In this work, we used molecular dynamic (MD) simulation to study trypsin with and without a six-amino-acid peptide bound in three different solvents (water, acetonitrile and hexane) in order to provide molecular information for well understanding the structure and function of enzymes in non-aqueous media. The results show that the enzyme is more compact and less native-like in hexane than in the other two polar solvents. The substrate could stabilize the native protein structure in the two polar media, but not in the non-polar hexane. There are no significant differences in the conformation of the S1 pocket upon the substrate binding in water and acetonitrile media while a reverse behavior is observed in hexane media, implying a possible induced fit binding mechanism in the non-polar media. The substrate binding enhances the stability of catalytic H-bond network since it could expel the solvent molecules from the active site. The enzyme and the substrate appear to be more appropriate to the reactive conformation in the organic solvents compared with aqueous solution. There is much greater substrate binding strength in hexane media than the water and acetonitrile ones since the polar solvent significantly weakens electrostatic interactions, which are observed to be the main driving force to the binding. In addition, some residues of the S1 pocket could remain favorable contribution to the binding despite the solvent change, but with differences in the contribution extent, the number and the type of residues between the three media.

  2. Electroenzymatic Reactions With Oxygen on Laccase-Modified Electrodes in Anhydrous (Pure) Organic Solvent

    DEFF Research Database (Denmark)

    Yarapolov, A.; Shleev, S.; Zaitseva, E.

    2007-01-01

    The electroenzymatic reactions of Trametes hirsuta laccase in the pure organic solvent dimethyl sulfoxide (DMSO) have been investigated within the framework for potential use as a catalytic reaction scheme for oxygen reduction. The bioelectrochemical characteristics of laccase were investigated...... in two different ways: (i) by studying the electroreduction of oxygen in anhydrous DMSO via a direct electron transfer mechanism without proton donors and (ii) by doing the same experiments in the presence of laccase substrates, which display in pure organic solvents both the properties of electron...... donors as well as the properties of weak acids. The results obtained with laccase in anhydrous DMSO were compared with those obtained previously in aqueous buffer. It was shown that in the absence of proton donors under oxygenated conditions, formation of superoxide anion radicals is prevented at bare...

  3. One-pot hydrothermal preparation of graphene sponge for the removal of oils and organic solvents

    Science.gov (United States)

    Wu, Ruihan; Yu, Baowei; Liu, Xiaoyang; Li, Hongliang; Wang, Weixuan; Chen, Lingyun; Bai, Yitong; Ming, Zhu; Yang, Sheng-Tao

    2016-01-01

    Graphene sponge (GS) has found applications in oil removal due to the hydrophobic nature of graphene sheets. Current hydrothermal preparations of GS use toxic reducing reagents, which might cause environmental pollution. In this study, we reported that graphene oxide (GO) could be hydrothermally reduced by glucose to form GS for the adsorption of oils and various organic solvents. Graphene sheets were reduced by glucose during the hydrothermal treatment and formed 3D porous structure. GS efficiently adsorbed organic solvents and oils with competitive adsorption capacities. GS was able to treat pollutants in pure liquid form and also in the simulated seawater. GS could be easily regenerated by evaporating or burning. After 10 cycles, the adsorption capacity still retained 77% by evaporating and 87% by burning. The implication to the applications of GS in water remediation is discussed.

  4. Lipophilic polyelectrolyte gels as super-absorbent polymers for nonpolar organic solvents.

    Science.gov (United States)

    Ono, Toshikazu; Sugimoto, Takahiro; Shinkai, Seiji; Sada, Kazuki

    2007-06-01

    Polyelectrolyte gels that are known as super-absorbent polymers swell and absorb water up to several hundred times their dried weights and have become ubiquitous and indispensable materials in many applications. Their superior swelling abilities originate from the electrostatic repulsion between the charges on the polymer chains and the osmotic imbalance between the interior and exterior of the gels. However, no super-absorbent polymers for volatile organic compounds (VOCs), and especially for nonpolar organic solvents (epsilonpolymer networks. This expands the potential of polyelectrolytes that have been used only in aqueous solutions or highly polar solvents, and provides soft materials that swell in a variety of media. These materials could find applications as protective barriers for VOCs spilled in the environment and as absorbents for waste oil.

  5. Stabilities and conformational transitions of various proteases in the presence of an organic solvent.

    Science.gov (United States)

    Ogino, Hiroyasu; Gemba, Yuichi; Yutori, Yoshikazu; Doukyu, Noriyuki; Ishimi, Kosaku; Ishikawa, Haruo

    2007-01-01

    The half-life of the activity of the PST-01 protease that was secreted by organic solvent-tolerant Pseudomonas aeruginosa PST-01 was very long in the presence of methanol as compared to that in the absence of methanol. The conformational transitions of the PST-01 protease, alpha-chymotrypsin, thermolysin, and subtilisin in the presence and absence of methanol were monitored by measuring the CD spectra. The conformational stabilities of the PST-01 protease and subtilisin in the presence of methanol were higher than those in the absence of methanol. This resulted in high stability of these proteases in the presence of methanol. Furthermore, it was suggested that the organic solvent stabilities of enzymes were closely related to the secondary structure by monitoring the conformational transitions of polyamino acids, which form the particular conformations, in the presence and absence of methanol.

  6. [Identification of organic solvents in the water of a freshly coated drinking-water reservoir].

    Science.gov (United States)

    Karrenbrock, F; Haberer, K

    1982-01-01

    Chloro-caoutschouc coatings on reservoirs made of concrete can release organic solvents to the drinking water for several month after applying. These solvents can be identified directly in the water by highly sensitive analytical methods (GC/MS). The concentrations verified distinctly exceed the maximum permissible concentration of 10 micrograms/l as suggested by the EEG for the parameter: "dissolved or emulsified hydrocarbons (after extraction by petroleum ether); mineral oils" (2). Protective chloro-caoutchouc coatings should therefore be tested for the release of organic substances to water according to the KTW-Recommendations of the German Federal Health Bureau (1). In future drinking water reservoirs should not be coated unless compelling reasons exist, such as to protect concrete against aggressive water.

  7. PRODAN dual emission feature to monitor BHDC interfacial properties changes with the external organic solvent composition.

    Science.gov (United States)

    Agazzi, Federico M; Rodriguez, Javier; Falcone, R Dario; Silber, Juana J; Correa, N Mariano

    2013-03-19

    We have investigated the water/benzyl-n-hexadecyldimethylammonium chloride (BHDC)/n-heptane:benzene reverse micelles (RMs) interfaces properties using 6-propionyl-2-(N,N-dimethyl)aminonaphthalene, PRODAN, as molecular probe. We have used absorption and emission (steady-state and time-resolved) spectroscopy of PRODAN to monitor the changes in the RMs interface functionalities upon changing the external organic solvent blend. We demonstrate that PRODAN is a useful probe to investigate how the external solvent composition affects the micelle interface properties. Our results show that changes in the organic solvent composition in water/BHDC/n-heptane:benzene RMs have a dramatic effect on the photophysics of PRODAN. Thus, increasing the aliphatic solvent content over the aromatic one produces PRODAN partition and PRODAN intramolecular electron transfer (ICT) processes. Additionally, the water presence in these RMs makes the PRODAN ICT process favored with the consequent decreases in the LE emission intensity and a better definition of the charge transfer (CT) band. All this evidence suggests that the benzene molecules are expelled out of the interface, and the water-BHDC interactions are stronger with more presence of water molecules in the polar part of the interface. Thus, we demonstrate that a simple change in the composition of the external phase promotes remarkable changes in the RMs interface. Finally, the results obtained with PRODAN together with those reported in a previous work in our lab reveal that the external phase is important when trying to control the properties of RMs interface. It should be noted that the external phase itself, besides the surfactant and the polar solvent sequestrated, is a very important control variable that can play a key role if we consider smart application of these RMs systems.

  8. Organic compounds of different extractability in total solvent extracts from soils of contrasting water repellency

    Science.gov (United States)

    Atanassova, Irena; Doerr, Stefan H.

    2010-05-01

    Previous studies examining organic compounds that may cause water-repellent behaviour of soils have typically focussed on analysing only the lipophilic fraction of extracted material. This study aimed to provide a more comprehensive examination by applying single- and sequential-accelerated solvent extraction (ASE), separation and analysis by GC/MS of the total solvent extracts of three soils taken from under eucalypt vegetation with different levels of water repellency. Water repellency increased in all the soils after extraction with DCM:MeOH (95:5), but was eliminated with iso-propanol/ammonia (95:5). Quantities of major lipid compound classes varied between solvents and soils. Iso-propanol/ammonia (95:5) solvent released saccharides, glycerol, aromatic acids and other polar organic compounds, which were more abundant in fractionated extracts from the single extraction and the third step sequential ASE extraction, than in the extracts from the DCM:MeOH ASE solvent. Dominant compounds extracted from all soils were long-chain alkanols (>C22), palmitic acid, C29 alkane, β-sitosterol, terpenes, terpenoids and other polar compounds. The soil with smallest repellency lacked >C18 fatty acids and had smallest concentrations of alkanols (C26, C28 and C30) and alkanes (C29, C31), but a greater abundance of more complex polar compounds than the more repellent soils. We therefore speculate that the above compounds play an important role in determining the water repellency of the soils tested. The results suggest that one-stage and sequential ASE extractions with iso-propanol:ammonia and subsequent fractionation of extracts are a useful approach in providing a comprehensive assessment of the potential compounds involved in causing soil water repellency.

  9. Neurotoxic effects of organic solvents among workers in paint and lacquer manufacturing industry

    Directory of Open Access Journals (Sweden)

    Jovanović Jovica M.

    2004-01-01

    Full Text Available Introduction Organic solvents are chemically different compounds with one common feature: they dissolve fats, oils, resins, cellulose acetate and cellulose nitrate, which makes them widely used in industry. Most often organic solvents are used in paint and lacquer industries, in production of pesticides, plastics, explosives, rubber, cellulose, air conditioners, in pharmaceutical industry and in leather industry. The aim of this research was to analyze the working environment and professional hazards in paint and lacquer manufacturing industry and evaluate effects of chronic exposure to mixture of organic solvents on nervous system of exposed workers. Methodology The exposed group consisted of 50 workers professionally exposed to these noxae, while the control group consisted of 30 workers who have never been exposed to these noxae. Results Examination of working environment in departments of paint and lacquer manufacturing revealed presence of white spirit and toluene above allowed levels. Exposed workers more frequently complained of fatigue, hand numbness, enhanced excitation, and concentration difficulties, forgetfulness and headaches, than workers from the control group. Electroneurographic examination of n. medianus showed reduced motor and sensitive conduction velocity among exposed in comparison to workers from the control group. Reduced motor and sensitive conduction velocity was correlated with duration of exposure to these noxae. Terminal latency of n. medianus was statistically, significantly longer in the exposed group than in the control group. Workers in the exposed group have statistically significantly longer reaction time in response to acoustic and visual stimuli. Discussion Segmental demyelination and axonal degeneration, as forms of damage to peripheral nerves, were identified as responsible for peripheral neuropathy associated with occupational exposure to organic solvents. Conclusion Results of this study show possible

  10. THERMODYNAMIC PARAMETERS OF SOLUTIONS OF SILDENAFIL CITRATE IN SOME ORGANIC SOLVENTS AT DIFFERENT TEMPERATURES

    OpenAIRE

    S. BALUJA; K. Bhesaniya

    2015-01-01

    The solubility of Sildenafil citrate in some organic solvents; hexane, toluene,1-butanol and 1,2 dichloroethane has been determined using gravimetric method over different temperature range (298.15 K to 328.15 K) at one atmospheric pressure. The modified Apelblat and Buchowski-Ksiazczak λh equations were used to correlate the experimental solubility data. Further, various thermodynamic parameters have been evaluated from these solubility data.

  11. THERMODYNAMIC PARAMETERS OF SOLUTIONS OF SILDENAFIL CITRATE IN SOME ORGANIC SOLVENTS AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    S. Baluja

    2015-07-01

    Full Text Available The solubility of Sildenafil citrate in some organic solvents; hexane, toluene,1-butanol and 1,2 dichloroethane has been determined using gravimetric method over different temperature range (298.15 K to 328.15 K at one atmospheric pressure. The modified Apelblat and Buchowski-Ksiazczak λh equations were used to correlate the experimental solubility data. Further, various thermodynamic parameters have been evaluated from these solubility data.

  12. THERMODYNAMIC PARAMETERS OF SOLUTIONS OF SILDENAFIL CITRATE IN SOME ORGANIC SOLVENTS AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    S. Baluja

    2014-06-01

    Full Text Available The solubility of Sildenafil citrate in some organic solvents; hexane, toluene,1-butanol and 1,2 dichloroethane has been determined using gravimetric method over different temperature range (298.15 K to 328.15 K at one atmospheric pressure. The modified Apelblat and Buchowski-Ksiazczak λh equations were used to correlate the experimental solubility data. Further, various thermodynamic parameters have been evaluated from these solubility data.

  13. Lignin Peroxidase Oxidation of Aromatic Compounds in Systems Containing Organic Solvents

    OpenAIRE

    Vazquez-Duhalt, Rafael; Westlake, Donald W. S.; Fedorak, Phillip M.

    1994-01-01

    Lignin peroxidase from Phanerochaete chrysosporium was used to study the oxidation of aromatic compounds, including polycyclic aromatic hydrocarbons and heterocyclic compounds, that are models of moieties of asphaltene molecules. The oxidations were done in systems containing water-miscible organic solvents, including methanol, isopropanol, N, N-dimethylformamide, acetonitrile, and tetrahydrofuran. Of the 20 aromatic compounds tested, 9 were oxidized by lignin peroxidase in the presence of hy...

  14. Comparison of Methanol and Tetraglyme as Extraction Solvents for Determination of Volatile Organics in Soil

    Science.gov (United States)

    1987-11-01

    determining volatile organics in soil can be classified into thefollowing groups: 1. Static or dynamic headspace analysis 2. Solvent extraction-direct...methods based on the dynamic headspace method whereby the volatiles are stripped from a soil/water slurry using a conventional purge-and-trap instrument...651. Brazell, R.S. and MP. Maskarinec (1981) Dynamic headspace analysis of solid waste materials. Journal of High Resolution Chromatography and

  15. Study of the resolution of amino acids and aminoalcohols in organic solvents.

    Science.gov (United States)

    Orsini, F; Pelizzoni, F; Ghioni, C

    1995-06-01

    The enzymatic resolution of racemic phenylglycine, phenylglycinol and phenylalaninol has been studied in organic solvents under a variety of experimental conditions. Subtilisin in 3-methyl-3-pentanol was effective for the resolution of phenylglycine esters, via N-acylation with trifluoroethyl butyrate. Porcine pancreatic lipase in ethyl acetate gave satisfactory results in the resolution of phenylglycinol and phenylalaninol; theα orβ position of the phenyl group was found to influence both the rate and the chemioselectivity of the reaction.

  16. A calorimetric study of energy conversion efficiency of a sonochemical reactor at 500 kHz for organic solvents.

    Science.gov (United States)

    Toma, Maricela; Fukutomi, Satoshi; Asakura, Yoshiyuki; Koda, Shinobu

    2011-01-01

    It would seem that the economic viability is yet to be established for a great number of sonochemical processes, owning to their perfectible ultrasonic equipments. Industrial scale sonoreactors may become more important as a result of mastering the parameters with influence on their energy balance. This work related the solvent type to the energy efficiency as the first step of a complex study aiming to assess the energy balance of sonochemical reactors at 500 kHz. Quantitative measurements of ultrasonic power for water and 10 pure organic solvents were performed by calorimetry for a cylindrically shaped sonochemical reactor with a bottom mounted vibrating plate. It was found that the ultrasonic power is strongly related to the solvent, the energy conversion for organic liquids is half from that of water and there is a drop in energy efficiency for filling levels up to 250 mm organic solvents. Surface tension, viscosity and vapor pressure influence the energy conversion for organic solvents, but it is difficult explain these findings based on physical properties of solvents alone. The apparent intensity of the atomization process shows a good agreement with the experimentally determined values for energy conversion for water and the solvent group studied here. This study revealed that to attain the same ultrasonic power level, more electrical energy is need for organic solvents as compared to water. The energy balance equation has been defined based on these findings by considering an energy term for atomization.

  17. The Mammary Gland Carcinogens: The Role of Metal Compounds and Organic Solvents

    Directory of Open Access Journals (Sweden)

    Stephen Juma Mulware

    2013-01-01

    Full Text Available The increased rate of breast cancer incidences especially among postmenopausal women has been reported in recent decades. Despite the fact that women who inherited mutations in the BRCA1 and BRCA2 genes have a high risk of developing breast cancer, studies have also shown that significant exposure to certain metal compounds and organic solvents also increases the risks of mammary gland carcinogenesis. While physiological properties govern the uptake, intracellular distribution, and binding of metal compounds, their interaction with proteins seems to be the most relevant process for metal carcinogenicity than biding to DNA. The four most predominant mechanisms for metal carcinogenicity include (1 interference with cellular redox regulation and induction of oxidative stress, (2 inhibition of major DNA repair, (3 deregulation of cell proliferation, and (4 epigenetic inactivation of genes by DNA hypermethylation. On the other hand, most organic solvents are highly lipophilic and are biotransformed mainly in the liver and the kidney through a series of oxidative and reductive reactions, some of which result in bioactivation. The breast physiology, notably the parenchyma, is embedded in a fat depot capable of storing lipophilic xenobiotics. This paper reviews the role of metal compounds and organic solvents in breast cancer development.

  18. A New Method Without Organic Solvent to Targeted Nanodrug for Enhanced Anticancer Efficacy

    Science.gov (United States)

    Wu, Shichao; Yang, Xiangrui; Zou, Mingyuan; Hou, Zhenqing; Yan, Jianghua

    2017-06-01

    Since the hydrophobic group is always essential to the synthesis of the drug-loaded nanoparticles, a majority of the methods rely heavily on organic solvent, which may not be completely removed and might be a potential threat to the patients. In this study, we completely "green" synthesized 10-hydroxycamptothecine (HCPT) loaded, folate (FA)-modified nanoneedles (HFNDs) for highly efficient cancer therapy with high drug loading, targeting property, and imaging capability. It should be noted that no organic solvent was used in the preparation process. In vitro cell uptake study and the in vivo distribution study showed that the HFNDs, with FA on the surface, revealed an obviously targeting property and entered the HeLa cells easier than the chitosan-HCPT nanoneedles without FA modified (NDs). The cytotoxicity tests illustrated that the HFNDs possessed better killing ability to HeLa cells than the individual drug or the NDs in the same dose, indicating its good anticancer effect. The in vivo anticancer experiment further revealed the pronounced anticancer effects and the lower side effects of the HFNDs. This new method without organic solvent will lead to a promising sustained drug delivery system for cancer diagnosis and treatment.

  19. Enhancement of the aspartame precursor synthetic activity of an organic solvent-stable protease.

    Science.gov (United States)

    Ogino, Hiroyasu; Tsuchiyama, Shotaro; Yasuda, Masahiro; Doukyu, Noriyuki

    2010-03-01

    The PST-01 protease is highly stable and catalyzes the synthesis of the aspartame precursor with high reaction yields in the presence of organic solvents. However, the synthesis rate using the PST-01 protease was slower than that observed when thermolysin was used. Structural comparison of both enzymes showed particular amino acid differences near the active center. These few residue differences in the PST-01 protease were mutated to match those amino acid types found in thermolysin. The mutated PST-01 proteases at the 114th residue from tyrosine to phenylalanine showed enhancement of synthetic activity. This activity was found to be similar to thermolysin. In addition, mutating the residue in the PST-01 protease with arginine and serine showed more improvement of the activity. The mutant PST-01 protease should be more useful than thermolysin for the synthesis of the aspartame precursor, because this enzyme has higher stability and activity in the presence of organic solvents. The results show the potential of organic solvent-stable enzymes as industrial catalysts.

  20. Semipermanent capillary coatings in mixed organic-water solvents for CE.

    Science.gov (United States)

    Diress, Abebaw G; Yassine, Mahmoud M; Lucy, Charles A

    2007-04-01

    This report describes the creation of semipermanent capillary coatings that are compatible with organic-water solvent systems in CE. The coatings are created by simply rinsing the fused-silica capillary with long double-chain cationic surfactants, such as dimethyl-ditetradecyl ammonium bromide (2C(14)DAB), dihexadecyldimethyl ammonium bromide (2C(16)DAB), and dimethyldioctadecyl ammonium bromide (2C(18)DAB). These surfactants generate semipermanent bilayer coatings on the capillary surface, which display a high degree of stability in buffers containing up to 60% v/v of organic solvents, such as methanol and ACN. The coating stability increases with increasing hydrophobicity of the surfactant, i.e., with increasing chain length. For instance, the EOF changes by only 1.2% in a 2C(18)DAB-coated capillary after 130 capillary volumes of rinsing with 60% v/v methanol containing buffer. The bilayer coatings allow separations to be performed without the need to regenerate the coating between runs or to maintain the EOF modifier in the run buffer. Rapid separations (organic solvent content is adjusted.

  1. Understanding dissolution behavior of 193nm photoresists in organic solvent developers

    Science.gov (United States)

    Lee, Seung-Hyun; Park, Jong Keun; Cardolaccia, Thomas; Sun, Jibin; Andes, Cecily; O'Connell, Kathleen; Barclay, George G.

    2012-03-01

    Herein, we investigate the dissolution behavior of 193-nm chemically amplified resist in different organic solvents at a mechanistic level. We previously reported the effect of solvent developers on the negative tone development (NTD) process in both dry and immersion lithography, and demonstrated various resist performance parameters such as photospeed, critical dimension uniformity, and dissolution rate contrast are strongly affected by chemical nature of the organic developer. We further pursued the investigation by examining the dependence of resist dissolution behavior on their solubility properties using Hansen Solubility Parameter (HSP). The effects of monomer structure, and resist composition, and the effects of different developer chemistry on dissolution behaviors were evaluated by using laser interferometry and quartz crystal microbalance. We have found that dissolution behaviors of methacrylate based resists are significantly different in different organic solvent developers such as OSDTM-1000 Developer* and n-butyl acetate (nBA), affecting their resist performance. This study reveals that understanding the resist dissolution behavior helps to design robust NTD materials for higher resolution imaging.

  2. Purification and Characterization of Organic Solvent and Detergent Tolerant Lipase from Thermotolerant Bacillus sp. RN2

    Directory of Open Access Journals (Sweden)

    Tadahiko Kajiwara

    2010-09-01

    Full Text Available The aim of this study was to characterize the organic solvent and detergent tolerant properties of recombinant lipase isolated from thermotolerant Bacillus sp. RN2 (Lip-SBRN2. The isolation of the lipase-coding gene was achieved by the use of inverse and direct PCR. The complete DNA sequencing of the gene revealed that the lip-SBRN2 gene contains 576 nucleotides which corresponded to 192 deduced amino acids. The purified enzyme was homogeneous with the estimated molecular mass of 19 kDa as determined by SDS-PAGE and gel filtration. The Lip-SBRN2 was stable in a pH range of 9–11 and temperature range of 45–60 °C. The enzyme was a non metallo-monomeric protein and was active against pNP-caprylate (C8 and pNP-laurate (C12 and coconut oil. The Lip-SBRN2 exhibited a high level of activity in the presence of 108% benzene, 102.4% diethylether and 112% SDS. It is anticipated that the organic solvent and detergent tolerant enzyme secreted by Bacillus sp. RN2 will be applicable as catalysts for reaction in the presence of organic solvents and detergents.

  3. Extraction of lignins from aqueous-ionic liquid mixtures by organic solvents.

    Science.gov (United States)

    Xin, Qin; Pfeiffer, Katie; Prausnitz, John M; Clark, Douglas S; Blanch, Harvey W

    2012-02-01

    The commercial development of ionic liquids (ILs) to pretreat lignocellulose by dissolution of whole biomass and cellulose precipitation by addition of water is hindered by the absence of an effective technique to recover the lignin content of the biomass from the IL. Three organic solvents [ethyl acetate, 1,4-dioxane, and tetrahydrofuran (THF)] were studied for their ability to form a two-liquid-phase system with water and 1-ethyl-3-methylimidazolium acetate ([C(2)mim][OAc]), and for partitioning model lignins and lignin monomers between the two liquid phases. Ternary diagrams were obtained for three [C(2)mim][OAc]/organic solvent/water systems at 22°C. Partition coefficients were measured for several types of lignin in these three systems. Partition coefficients increase with rising water content in the IL phase, and depend strongly on the type of lignin and on the organic solvent. Partition coefficients rise as the pH of the ionic-liquid-rich phase falls. Small molecule model lignin monomer compounds (guaiacol, syringaldehyde) are also readily extracted from the IL/water system by THF. Copyright © 2011 Wiley Periodicals, Inc.

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

    Science.gov (United States)

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

    2016-08-01

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

  5. Real-time ESI-MS of enzymatic conversion: impact of organic solvents and multiplexing.

    Science.gov (United States)

    Scheerle, Romy K; Grassmann, Johanna; Letzel, Thomas

    2012-01-01

    Different enzymatic assays were characterized systematically by real-time electrospray ionization mass spectrometry (ESI-MS) in the presence of organic solvents as well as in multiplex approaches and in a combination of both. Typically, biological enzymatic reactions are studied in aqueous solutions, since most enzymes show their full activity solely in aqueous solutions. However, in recent years, the use of organic solvents in combination with enzymatic reactions has gained increasing interest due to biotechnological advantages in chemical synthesis, development of online coupled setups screening for enzyme regulatory compounds, advantages regarding mass spectrometric detection and others. In the current study, the influence of several common organic solvents (methanol, ethanol, isopropanol, acetone, acetonitrile) on enzymatic activity (hen egg white lysozyme, chitinase, α-chymotrypsin, elastase from human neutrophils and porcine pancreas, acetylcholinesterase) was tested. Moreover, multiplexing is a promising approach enabling fast and cost-efficient screening methods, e.g. for determination of inhibitors in complex mixtures or in the field of biomedical research. Although in multiplexed setups the enzymatic activity may be affected by the presence of other substrates and/or enzymes, the expected advantages possibly will predominate. To investigate those effects, we measured multiple enzymatic assays simultaneously. For all conducted measurements, the conversion rate of the substrate(s) was calculated, which reflects the enzymatic activity. The results provide an overview about the susceptibility of the selected enzymes towards diverse factors and a reference point for many applications in analytical chemistry and biotechnology.

  6. Coacervate Core Micelles for the Dispersion and Stabilization of Organophosphate Hydrolase in Organic Solvents

    Science.gov (United States)

    Mills, Carolyn; Obermeyer, Allie; Dong, Xuehui; Olsen, Bradley D.

    Bulk organophosphate (OP) nerve agents are difficult to decontaminate on site and dangerous to transport. The organophosphate hydrolase (OPH) enzyme is an efficient catalyst for hydrolyzing, and thus decontaminating, these compounds, but suffers from poor stability in the hydrophobic bulk OP environment. Here, we exploit the complex coacervation phase separation phenomenon to form complex coacervate core micelles (C3Ms) that can protect this OPH enzyme under these conditions. Stable C3Ms form when mixing a charged-neutral block copolymer methyl-quaternized poly(4-vinylpyridine)-block-poly(oligo(ethylene glycol) methacrylate) (Qp4vp- b-POEGMA), a homopolymer poly(acrylic acid) (PAA), and OPH under a certain conditions. The C3Ms are then transferred into two organic solvents, ethanol and dimethyl methylphosphonate (DMMP), which is a good simulant for the physical properties of the OP compounds. The C3Ms retain their nanostructures in the organic solvents. The activity test of OPH indicates that the C3Ms successfully protect OPH activity in organic solvents.

  7. [Cloning and expression of organic solvent tolerant lipase gene from Staphylococcus saprophyticus M36].

    Science.gov (United States)

    Tang, Yanchong; Lu, Yaping; Lü, Fengxia; Bie, Xiaomei; Guo, Yao; Lu, Zhaoxin

    2009-12-01

    Lipases are important biocatalysts that are widely used in food processing and bio-diesel production. However, organic solvents could inactivate some lipases during applications. Therefore, the efficient cloning and expression of the organic solvent-tolerant lipase is important to its application. In this work, we first found out an organic solvent-tolerant lipase from Staphylococcus saprophyticus M36 and amplified the 741 bp Lipase gene lip3 (GenBank Accession No. FJ979867), by PCR, which encoded a 31.6 kD polypeptide of 247 amino acid residues. But the lipase shared 83% identity with tentative lip3 gene of Staphylococcus saprophyticus (GenBank Accession No. AP008934). We connected the gene with expression vector pET-DsbA, transformed it into Escherichia coli BL21 (DE3), and obtained the recombinant pET-DsbA-lip3. With the induction by 0.4 mmol/L of isopropyl beta-D-thiogalactopyranoside at pH 8.0, OD600 1.0, 25 degrees C for 12 h, the lipase activity reached up to 25.8 U/mL. The lipase expressed was stable in the presence of methanol, n-hexane, and isooctane, n-heptane.

  8. [Exposure to volatile organic solvents in a group of carpentry craftsmen].

    Science.gov (United States)

    Miscetti, G; Garofani, P; Bodo, P; Mencarelli, A; Ballerani, A; Ceppitelli, A; Angeloni, R; Peccetti, V

    2003-01-01

    The wide use of volatile organic solvent-based products in wood carpentry and the possible effects of long-term exposure to low dose mixtures of these solvents prompted an investigation in a group of small enterprises. The investigation aimed at estimating risk in wood carpentry work via assessment of exposure. Exposure to solvents was studied in a group of 13 enterprises (selected from a group of 52), via personal samplings, both active and passive. The solvents to be examined were selected on the basis of the information contained in the technical-toxicity sheets of the products used in these factories. The results show an average exposure generally within the TLV-TWA recommended by the various industrial hygiene associations. However, considering the wide variability of the concentration values observed, the possibility that these limits might be exceeded in the long term cannot be excluded. Comparison of the results of active and passive samplings, showed a substantial similarity of the two systems, with evident advantages of the passive system, as far as ease of use, workers' acceptance and costs are concerned. The results of this study can be a useful reference for all those (employers, occupational physicians, technicians, workers' representatives) who are required to take preventive measures especially in cases where environmental investigations are hindered by technical difficulties or are not regularly used in evaluation systems.

  9. Lysozyme in water-acetonitrile mixtures: Preferential solvation at the inner edge of excess hydration

    Science.gov (United States)

    Sirotkin, Vladimir A.; Kuchierskaya, Alexandra A.

    2017-06-01

    Preferential solvation/hydration is an effective way for regulating the mechanism of the protein destabilization/stabilization. Organic solvent/water sorption and residual enzyme activity measurements were performed to monitor the preferential solvation/hydration of hen egg-white lysozyme at high and low water content in acetonitrile at 25 °C. The obtained results show that the protein destabilization/stabilization depends essentially on the initial hydration level of lysozyme and the water content in acetonitrile. There are three composition regimes for the dried lysozyme. At high water content, the lysozyme has a higher affinity for water than for acetonitrile. The residual enzyme activity values are close to 100%. At the intermediate water content, the dehydrated lysozyme has a higher affinity for acetonitrile than for water. A minimum on the residual enzyme activity curve was observed in this concentration range. At the lowest water content, the organic solvent molecules are preferentially excluded from the dried lysozyme, resulting in the preferential hydration. The residual catalytic activity is ˜80%, compared with that observed after incubation in pure water. Two distinct schemes are operative for the hydrated lysozyme. At high and intermediate water content, lysozyme is preferentially hydrated. However, in contrast to the dried protein, at the intermediate water content, the initially hydrated lysozyme has the increased preferential hydration parameters. At low water content, the preferential binding of the acetonitrile molecules to the initially hydrated lysozyme was detected. No residual enzyme activity was observed in the water-poor acetonitrile. Our data clearly show that the initial hydration level of the protein macromolecules is one of the key factors that govern the stability of the protein-water-organic solvent systems.

  10. [Liver function of workers occupationally exposed to mixed organic solvents in a petrochemical industry].

    Science.gov (United States)

    Fernández-D'Pool, J; Oroño-Osorio, A

    2001-06-01

    A descriptive and cross sectional study was conducted to determine whether hepatic function changes in workers occupationally exposed to a mixture of organic solvents, were due to the exposure or confusing factors. A non random sample of 77 workers, operators and supervisors of the Olefin Plant I and II of a petrochemical industry in Maracaibo, Venezuela, was used. Their mean age was 29 +/- 7 years, and had at least one year of exposure to the solvents. This sample was compared with a group of employees of the administrative offices or control panel workers, with a mean age of 36 +/- 8 year and with similar anthropometric characteristics. Workers with a known history of liver disease, blood transfusions and diabetes mellitus were excluded of the study. In addition to a complete occupational disease medical history and a physical examination, serum samples were obtained to determine the activity of the aspartato aminotransferase (AST), alanin aminotransferase (ALT), gamma glutamiltransferase (GGT), alkaline phosphatase (AF), the concentration of the total bile acids (BAS), the surface antigen of hepatitis B(HbsAg) and the hepatitis A virus antibodies: AntiHAV-IgG and the AntiHAV-IgM. An urine sample was taken and analyzed by standard methodology to determine urinary phenols. The air concentrations of benzene, ethylbenzene, toluene and xylene were analyzed by gas chromathography. The serum activities of the liver enzymes, the concentration of bile acids and urinary phenols were not influenced by the exposure to the solvents. The increase of the activity of GGT was associated with obesity and alcohol consumption. The antibodies of the surface antigen of hepatitis A-IgM were normal in both groups and the antibodies for the antigen of hepatitis A-IgG presented a prevalence of 6% in the exposed group and 9% in the non exposed not being associated with liver abnormalities. The individual air concentrations of the solvents were below the environmentally permissible

  11. Impact of solvent extraction organics on adsorption and bioleaching of A. ferrooxidans and L. ferriphilum

    Science.gov (United States)

    Hualong, Yu; Xiaorong, Liu

    2017-04-01

    Copper solvent extraction entrained and dissoluted organics (SX organics) in the raffinate during SX operation can contaminated chalcopyrite ores and influence bioleaching efficiency by raffinate recycling. The adsorption and bioleaching of A. ferrooxidans and L. ferriphilum with contaminated ores were investigated. The results showed that, A. ferrooxidans and L. ferriphilum cells could adsorb quickly on minerals, the adsorption rate on contaminated ores were 83% and 60%, respectively, larger than on uncontaminated ores. However, in the bioleaching by the two kinds of acid bacterias, contaminated ores presented a lower bioleaching efficiency.

  12. Activity of α-Chymotrypsin Enhanced in the Presence of Iron Oxide Nanoparticles in Organic Solvent: Application to Peptide Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheolwoo; Kim, Mahnjoo [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

    2013-03-15

    We have demonstrated that α-CT displays a significantly enhanced activity in the presence of IONs relative to its IONs-free counterparts in organic solvent. IONs-activated α-CT catalyzed efficiently the synthesis of peptides without the formation of hydrolyzed byproducts. Enzymes are a useful class of catalysts for the preparation of enantiomeric compounds. The applications of enzymes in synthetic transformations, however, are limited by their reduced activities in organic solvent. Particularly, proteases such as subtilisin and α-chymotrypsin display several orders of magnitude lower activities in organic solvent than their aqueous counterparts.

  13. Effect of water-miscible organic solvents on CYP450-mediated metoprolol and imipramine metabolism in rat liver microsomes

    Directory of Open Access Journals (Sweden)

    T S Shah

    2015-01-01

    Full Text Available The catalytic activity of cytochrome P450 enzymes is known to be affected by presence of organic solvents in in vitro assays. However, these effects tend to be variable and depend on the substrate and CYP450 isoform in question. In the present study, we have investigated effect of ten water miscible organic solvents (methanol, ethanol, propanol, isopropanol, acetone, acetonitrile, dimethylsulphoxide, dimethylformamide, dioxane and PEG400 on water soluble substrates of CYP450, metoprolol and imipramine, at 0, 0.1, 0.25, 0.5, 0.75 and 1% v/v concentration in rat liver microsomes. Organic solvents studied had a concentration dependent inhibitory effect on the metoprolol and imipramine metabolism activity. Metoprolol metabolism was found to be more susceptible to the organic solvents, almost all the ten solvents had more or less inhibitory effect compared to imipramine metabolism. Except acetone, PEG400 and dimethylsulphoxide, all solvents had ~50% inhibition of total metoprolol metabolism activity, while in case of imipramine metabolism activity, only n-propanol, isopropanol and PEG400 had ~50% inhibition at 1% v/v. Interestingly, methanol, dimethylsulphoxide and acetonitrile had negligible effect on the imipramine metabolism (less than 10% inhibition at 1% v/v while, total metoprolol metabolism activity was substantially inhibited by these solvents (MeOH 52%, DMSO 29% and ACN 47% at 1% v/v. In both cases, dioxane was found to be the most inhibitory solvent (~90% inhibition at 1% v/v.

  14. Effect of Water-miscible Organic Solvents on CYP450-mediated Metoprolol and Imipramine Metabolism in Rat Liver Microsomes.

    Science.gov (United States)

    Shah, T S; Kamble, S H; Patil, Pranali G; Iyer, K R

    2015-01-01

    The catalytic activity of cytochrome P450 enzymes is known to be affected by presence of organic solvents in in vitro assays. However, these effects tend to be variable and depend on the substrate and CYP450 isoform in question. In the present study, we have investigated effect of ten water miscible organic solvents (methanol, ethanol, propanol, isopropanol, acetone, acetonitrile, dimethylsulphoxide, dimethylformamide, dioxane and PEG400) on water soluble substrates of CYP450, metoprolol and imipramine, at 0, 0.1, 0.25, 0.5, 0.75 and 1% v/v concentration in rat liver microsomes. Organic solvents studied had a concentration dependent inhibitory effect on the metoprolol and imipramine metabolism activity. Metoprolol metabolism was found to be more susceptible to the organic solvents, almost all the ten solvents had more or less inhibitory effect compared to imipramine metabolism. Except acetone, PEG400 and dimethylsulphoxide, all solvents had ~50% inhibition of total metoprolol metabolism activity, while in case of imipramine metabolism activity, only n-propanol, isopropanol and PEG400 had ~50% inhibition at 1% v/v. Interestingly, methanol, dimethylsulphoxide and acetonitrile had negligible effect on the imipramine metabolism (less than 10% inhibition at 1% v/v) while, total metoprolol metabolism activity was substantially inhibited by these solvents (MeOH 52%, DMSO 29% and ACN 47% at 1% v/v). In both cases, dioxane was found to be the most inhibitory solvent (~90% inhibition at 1% v/v).

  15. Vapour permeation for the recovery of organic solvents from waste air streams: separation capacities and process optimization

    NARCIS (Netherlands)

    Leemann, M.; Leemann, M.; Eigenberger, G.; Strathmann, H.

    1996-01-01

    Vapour permeation is a potentially suitable technology for the recovery of organic solvents from waste air streams. New solvent stable capillary membrane modules that are currently emerging on the market provide large membrane areas for an acceptable price and enhance the competitiveness of this

  16. Nickel-Catalyzed Suzuki-Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory

    Science.gov (United States)

    Hie, Liana; Chang, Jonah J.; Garg, Neil K.

    2015-01-01

    A modern undergraduate organic chemistry laboratory experiment involving the Suzuki-Miyaura coupling is reported. Although Suzuki-Miyaura couplings typically employ palladium catalysts in environmentally harmful solvents, this experiment features the use of inexpensive nickel catalysis, in addition to a "green" alcohol solvent. The…

  17. Nickel-Catalyzed Suzuki-Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory

    Science.gov (United States)

    Hie, Liana; Chang, Jonah J.; Garg, Neil K.

    2015-01-01

    A modern undergraduate organic chemistry laboratory experiment involving the Suzuki-Miyaura coupling is reported. Although Suzuki-Miyaura couplings typically employ palladium catalysts in environmentally harmful solvents, this experiment features the use of inexpensive nickel catalysis, in addition to a "green" alcohol solvent. The…

  18. SOLVENT POLARITY AND INTERNAL STRESSES CONTROL THE SWELLING BEHAVIOUR OF GREEN WOOD DURING DEHYDRATION IN ORGANIC SOLUTION

    Directory of Open Access Journals (Sweden)

    Shanshan Chang,

    2012-04-01

    Full Text Available The dimensional variations of green wood samples induced by organic solvents have been studied. The solvents used (ethanol, isopropanol, acetone, and acetonitrile covered a wide range of polarity and were studied pure and in aqueous solutions over a wide range of concentrations. Samples of normal and tension wood of poplar were used in order to minimize the effect of hydrophobic extractives on the wood-solvent interactions. The evolution of wood volume and of tangential strain with the concentration of the organic solvents shows a behavior similar to gels, with a significant swelling for solutions of intermediate polarity. The similarity of volume obtained in water and less polar pure organic solvents strikingly contrasted the different effects of water and organic solvents on dry wood. Low-polarity solvents were extremely effective in the stress release of tension wood, as indicated by the pattern of longitudinal shrinkage. Solvent exchange does not affect the mesoporous structure of the cell walls of tension wood and is a promising way to reduce internal stress in wood products.

  19. Thermodynamics of solvent interaction with the metal-organic framework MOF-5.

    Science.gov (United States)

    Akimbekov, Zamirbek; Wu, Di; Brozek, Carl K; Dincă, Mircea; Navrotsky, Alexandra

    2016-01-14

    The inclusion of solvent in metal-organic framework (MOF) materials is a highly specific form of guest-host interaction. In this work, the energetics of solvent MOF-5 interactions has been investigated by solution calorimetry in 5 M sodium hydroxide (NaOH) at room temperature. Solution calorimetric measurement of enthalpy of formation (ΔH(f)) of Zn4O(C8H4O4)3·C3H7NO (MOF-5·DMF) and Zn4O(C8H4O4)3·0.60C5H11NO (MOF-5·0.60DEF) from the dense components zinc oxide (ZnO), 1,4-benzenedicarboxylic acid (H2BDC), N,N-dimethylformamide (DMF) and N,N-diethylformamide (DEF) gives values of 16.69 ± 1.21 and 45.90 ± 1.46 kJ (mol Zn4O)(-1), respectively. The enthalpies of interaction (ΔH(int)) for DMF and DEF with MOF-5 are -82.78 ± 4.84 kJ (mol DMF)(-1) and -89.28 ± 3.05 kJ (mol DEF)(-1), respectively. These exothermic interaction energies suggest that, at low guest loading, Lewis base solvents interact more strongly with electron accepting Zn4O clusters in the MOF than at high solvent loading. These data provide a quantitative thermodynamic basis to investigate transmetallation and solvent assisted linker exchange (SALE) methods and to synthesize new MOFs.

  20. Solid lipid nanoparticles for encapsulation of hydrophilic drugs by an organic solvent free double emulsion technique.

    Science.gov (United States)

    Becker Peres, Luana; Becker Peres, Laize; de Araújo, Pedro Henrique Hermes; Sayer, Claudia

    2016-04-01

    Encapsulation of hydrophilic compounds for drug delivery systems with high loading efficiency is not easily feasible and remains a challenge, mainly due to the leaking of the drug to the outer aqueous phase during nanoparticle production. Usually, encapsulation of hydrophilic drugs is achieved by using double emulsion or inverse miniemulsion systems that often require the use of organic solvents, which may generate toxicological issues arising from solvent residues. Herein, we present the preparation of solid lipid nanoparticles loaded with a hydrophilic compound by a novel organic solvent free double emulsion/melt dispersion technique. The main objective of this study was to investigate the influence of important process and formulation variables, such as lipid composition, surfactant type, sonication parameters and lipid solidification conditions over physicochemical characteristics of SLN dispersion. Particle size and dispersity, as well as dispersion stability were used as responses. SLN dispersions with average size ranging from 277 to 550 nm were obtained, showing stability for over 60 days at 4 °C depending on the chosen emulsifying system. Entrapment efficiency of fluorescent dyes used as model markers was assessed by fluorescence microscopy and UV-vis spectrophotometry and results suggest that the obtained lipid based nanoparticles could be potentially applied as a delivery system of water soluble drugs.

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

    Science.gov (United States)

    Singh, Priyanka; Prakash, Rajiv; Shah, Kavita

    2012-08-15

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

  2. Effect of Water Miscible Organic Solvents on p-Nitrophenol Hydroxylase (CYP2E1) Activity in Rat Liver Microsomes.

    Science.gov (United States)

    Patil, Pranali G; Kamble, S H; Shah, T S; Iyer, K R

    2015-01-01

    Organic solvents used for solubilization of the substrates/NCEs are known to affect the activity of cytochrome P450 enzymes. Further, this effect varies with the solvents used, the substrates and CYP450 isoforms in question. In the present study, we have investigated the effect of ten commonly used water miscible organic solvents (methanol, ethanol, 1-propanol, 2-propanol, acetonitrile, acetone, dimethyl sulphoxide, N,N-dimethyl formamide, dioxane and polyethylene glycol 400) on p-nitrophenol hydroxylase activity at 0, 0.1, 0.25, 0.5, 0.75 and 1% v/v concentration in rat liver microsomes. All the solvents studied showed concentration dependent inhibition of the p-nitrophenol hydroxylase activity except acetonitrile which showed activation of the activity at concentration range studied. Out of ten solvents studied, dioxane was found to be the most inhibitory solvent (inhibition >90% at 0.25% v/v concentration). Overall, solvents like dimethyl sulphoxide, dimethyl formamide and dioxane appeared to be unsuitable for characterizing p-nitrophenol hydroxylase (CYP2E1-mediated) reactions due to a high degree of inhibition. On the other hand, methanol and acetonitrile at concentrations <0.5% v/v appeared to be appropriate solvents for substrate solubilization while evaluating CYP2E1-mediated catalysis. The results of this study imply that caution should be exercised while choosing solvents for dissolution of substrate during enzyme studies in liver microsomes.

  3. Effect of water miscible organic solvents on p-nitrophenol hydroxylase (CYP2E1 activity in rat liver microsomes

    Directory of Open Access Journals (Sweden)

    Pranali G Patil

    2015-01-01

    Full Text Available Organic solvents used for solubilization of the substrates/NCEs are known to affect the activity of cytochrome P450 enzymes. Further, this effect varies with the solvents used, the substrates and CYP450 isoforms in question. In the present study, we have investigated the effect of ten commonly used water miscible organic solvents (methanol, ethanol, 1-propanol, 2-propanol, acetonitrile, acetone, dimethyl sulphoxide, N,N-dimethyl formamide, dioxane and polyethylene glycol 400 on p-nitrophenol hydroxylase activity at 0, 0.1, 0.25, 0.5, 0.75 and 1% v/v concentration in rat liver microsomes. All the solvents studied showed concentration dependent inhibition of the p-nitrophenol hydroxylase activity except acetonitrile which showed activation of the activity at concentration range studied. Out of ten solvents studied, dioxane was found to be the most inhibitory solvent (inhibition >90% at 0.25% v/v concentration. Overall, solvents like dimethyl sulphoxide, dimethyl formamide and dioxane appeared to be unsuitable for characterizing p-nitrophenol hydroxylase (CYP2E1-mediated reactions due to a high degree of inhibition. On the other hand, methanol and acetonitrile at concentrations <0.5% v/v appeared to be appropriate solvents for substrate solubilization while evaluating CYP2E1-mediated catalysis. The results of this study imply that caution should be exercised while choosing solvents for dissolution of substrate during enzyme studies in liver microsomes.

  4. Reversible brain damage following acute organic solvents' poisoning determined by magnetic resonance

    Directory of Open Access Journals (Sweden)

    Dujmović Irena

    2005-01-01

    Full Text Available Introduction. Acute exposure to the effects of volatile solvents is characterized by the abrupt onset of symptoms and signs of poisoning, and relatively fast recovery in the majority of cases. Case report. We report a 24-year-old patient with an acute, accidental poisoning with a mixture of volatile organic solvents (most probably toluene, styrene and xylene, which led to the development of upward gaze paresis, diplopia, hemiparesis, ataxic gate, and the late onset truncal ataxia episodes. After 6 weeks, he recovered completely, while his extensive brain MRI lesions in the caudate nuclei, laterobasal putaminal regions, bilateral anterior insular cortex, central midbrain tegmental area withdrew completely after 4 months. Conclusion. Acute toxic encephalopathy should be a part of the differential diagnosis in any patient with acute neurobehavioral and neurological deficit.

  5. Ionic Liquids Beyond Simple Solvents: Glimpses at the State of the Art in Organic Chemistry.

    Science.gov (United States)

    Kuchenbuch, Andrea; Giernoth, Ralf

    2015-12-01

    Within the last 25 years ionic liquids have written a tremendous success story, which is documented in a nearly uncountable amount of original research papers, reviews, and numerous applications in research and industry. These days, ionic liquids can be considered as a mature class of compounds for many different applications. Frequently, they are used as neoteric solvents for chemical tansformations, and the number of reviews on this field of research is huge. In this focused review, though, we are trying to evaluate the state of the art of ionic liquid chemistry beyond using them simply as solvents for chemical transformations. It is not meant to be a comprehensive overview on the topic; the choice of emphasis and examples rather refects the authors' personal view on the field. We are especially highlighting fields in which we believe the most fundamental developments within the next five years will take place: biomass processing, (chiral) ionic liquids from natural sources, biotransformations, and organic synthesis.

  6. Synthesis and characterization of monodisperse CdSe quantum dots in different organic solvents

    Institute of Scientific and Technical Information of China (English)

    He Rong; You Xiaogang; Tian Hongye; Gao Feng; Cui Daxiang; Gu Hongchen

    2006-01-01

    Nearly monodisperse CdSe quantum dots (QDs)have been prepared by a soft solution approach using air-stable reagents in different organic solvents.This scheme is a supplement to the conventional thermal decomposition of organometailic compounds at higher temperatures.CdSe nanocrystals of different sizes could be obtained by simply changing the solvent.This method is reproducible and simple and thus can be readily scaled up for industrial production.The reaction process was monitored by the temporal evolution of the UV-Vis absorption and room temperature photoluminensce spectra.The structures of the CdSe quantum dots were determined by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM).The phase-transfer of oleic acid-stabilized CdSe nanocrystals into PBS buffer solutions was also studied for their potentials in biological applications.

  7. Barrierity of hydrogenated butadiene-acrylonitrile rubber and butyl rubber after exposure to organic solvents.

    Science.gov (United States)

    Krzemińska, Sylwia; Rzymski, Władysław M

    2011-01-01

    Resistance of antichemical clothing primarily depends on the type of material it is made from, in particular on the type of polymer used for coating the fabric carrier. This paper reports on systematic investigations on the influence of the cross-linking density of an elastomer and the composition of a cross-linked elastomer on its resistance to permeation of selected organic solvents. Tests of barrier material samples made from nonpolar butyl rubber (IIR) and polar hydrogenated butadiene-acrylonitrile rubber (HNBR) showed that (a) in rubber-solvent systems with medium thermodynamic affinity, cross-linking density influenced resistance to permeation and (b) the polarity of the system had a significant influence on barrierity.

  8. Organic carbonates as alternative solvents for palladium-catalyzed substitution reactions.

    Science.gov (United States)

    Schäffner, Benjamin; Holz, Jens; Verevkin, Sergey P; Börner, Armin

    2008-01-01

    Organic carbonates, such as propylene carbonate, butylene carbonate, and diethyl carbonate, were tested in the Pd-catalyzed asymmetric allylic substitution reactions of rac-1,3-diphenyl-3-acetoxy-prop-1-ene with dimethyl malonate or benzylamine as nucleophiles. Bidentate diphosphanes were used as chiral ligands. The application of monodentate phosphanes capable of self-assembling with the metal was likewise tested. In the substitution reaction with dimethyl malonate, enantioselectivities up to 98% were achieved. In the amination reaction, the chiral product was obtained with up to 83% ee. The results confirm that these "green solvents" can be advantageously used for this catalytic transformation as an alternative to those solvents usually employed which run some risk of being harmful to the environment.

  9. Ozone facilitated dechlorination of 2-chloroethanol and impact of organic solvents and activated charcoal.

    Science.gov (United States)

    Gounden, Asogan N; Jonnalagadda, Sreekanth B

    2013-10-01

    The ozone-initiated oxidation of 2-chloroethanol was followed by monitoring the consumption of the halogenated organic substrate. Gas chromatographic analysis of the ozonated products showed an increase in conversion from about 1 % after 3 h of ozone treatment to about 22 % after 12 h. The yields of major ozonated products identified and quantified namely acetaldehyde, acetic acid, and chloride ion increased proportionately as a function of ozone treatment time. The percent conversion of 2-chloroethanol in the presence of acetic acid or ethyl acetate were found to be higher than those under solvent-free conditions with similar products obtained. The use of activated charcoal during the ozonolyis of 2-chloroethanol showed a significant increase in the percent conversion of the substrate compared to solvent free ozonation. Based on the experimental findings, the overall mechanism for the reaction between 2-chloroethanol and ozone is described.

  10. The effect of solvent on the kinetics of the oxidation of benzaldehydes by quinolinium chlorochromate in aqueous organic solvent media

    Directory of Open Access Journals (Sweden)

    G. FATIMA JEYANTHI

    2002-12-01

    Full Text Available The kinetics of the oxidation of benzaldehyde and para-substituted benzaldehydes by quinolinium chlorochromate in water-dimethylformamide mixtures has been studied under pseudo-first-order conditions at 25±0.2°C. The operation of non-specific and specific solvent-solute interactions was explored by correlating the rate data with solvent parameters through a correlation analysis technique. Both electron-releasing and electron-withdrawing substitutents enhance the rate of oxidation and the Hammett plot shows a break in the reactivity order indicating the applicability of a dual mechanism.

  11. Hydrothermal liquefaction of palm oil empty fruit bunch (EFB) into bio-oil in different organic solvents

    Science.gov (United States)

    Sarwono, Rakhman; Pusfitasari, Eka Dian; Ghozali, Muhammad

    2016-06-01

    Thermochemical Liquefaction of empty fruit bunch (EFB) of palm oil in different organic solvents (water, methanol, ethanol, acetone, toluene and hexane) were comparatively investigated. Experiments were carried out in an autoclave at different temperatures of 300, 350 and 400 °C with a fixed solid/liquid rasio of 3 gram in 50 ml solvent, without catalysts and reaction time of 5 hours. The efficiency of above solvents in terms of conversion rate, soluble liquid and carbon products were investigated in the experiments. Increasing the reaction temperature increased the conversion rate in all organic solvents and water, but gaseous products also increased using a reaction temperature of 400 oC. The water solvent gave higher conversion rate of 49.14%, while toluene, acetone, methanol, hexane and ethanol gave conversion of 35.76%, 26.5%, 25.98%, 24.26 %, and 22.24%, respectively. The bio-oil produced in order of the largest amount were using methanol, water, ethanol, toluene, acetone, and hexane solvents. The chemical properties of bio-oil products were significantly affected by the type of liquefaction solvent. The composition of bio-oil consisted of mostly of a mixture of organic acids, ketones, and esters. The methanol and ethanol solvents resulted in mostly esters, while toluene and hexane resulted in mostly organic acids. Acetone solvent resulted in the same amount of organic acid and esters. In water as a solvent resulted in 2-pentanone, 4-hydroxy-4-methyl. The bio-oil consisted of a range of carbon C6 - C20 fragments.

  12. Anti nitrous reagents in organic solvent: the case of the n-tributylphosphate

    Energy Technology Data Exchange (ETDEWEB)

    Pochon, P.; Moisy, Ph.; Bisel, I.; Sans, D.; Maurin, J

    2004-07-01

    In order to stabilize uranium(IV) in Purex solvent (TBP 30% - alkane) during reductive stripping operations, nitrous acid elimination in the organic phase is needed to fulfill hydrazinium nitrate action in aqueous phase. In this field, organic phase soluble reagents like oximes, and substituted hydroxyl-amines or hydrazines have been selected and studied. A reactivity comparison with nitrous acid has been established from kinetic constants determination in nitric acid media. Nitrous acid destruction in organic phase (equilibrated with nitric acid) has then been observed for the most efficient molecules for which distribution coefficient have also been measured under process representative conditions. Analytical developments therefore needed are shown. Stability under acid and alkaline hydrolysis has also been investigated. Finally, stability of uranium(IV) in organic phase (TBP 30% vol. - alkane) in the presence of plutonium(III) has been checked for most attractive reagents. (authors)

  13. Application of natural deep eutectic solvents to the extraction of anthocyanins from Catharanthus roseus with high extractability and stability replacing conventional organic solvents.

    Science.gov (United States)

    Dai, Yuntao; Rozema, Evelien; Verpoorte, Robert; Choi, Young Hae

    2016-02-19

    Natural deep eutectic solvents (NADES) have attracted a great deal of attention in recent times as promising green media. They are generally composed of neutral, acidic or basic compounds that form liquids of high viscosity when mixed in certain molar ratio. Despite their potential, viscosity and acid or basic nature of some ingredients may affect the extraction capacity and stabilizing ability of the target compounds. To investigate these effects, extraction with a series of NADES was employed for the analysis of anthocyanins in flower petals of Catharanthus roseus in combination with HPLC-DAD-based metabolic profiling. Along with the extraction yields of anthocyanins their stability in NADES was also studied. Multivariate data analysis indicates that the lactic acid-glucose (LGH), and 1,2-propanediol-choline chloride (PCH) NADES present a similar extraction power for anthocyanins as conventional organic solvents. Furthermore, among the NADES employed, LGH exhibits an at least three times higher stabilizing capacity for cyanidins than acidified ethanol, which facilitates their extraction and analysis process. Comparing NADES to the conventional organic solvents, in addition to their reduced environmental impact, they proved to provide higher stability for anthocyanins, and therefore have a great potential as possible alternatives to those organic solvents in health related areas such as food, pharmaceuticals and cosmetics.

  14. Investigation of electrochemical degradation and application of e-paper dyes in organic solvents

    Institute of Scientific and Technical Information of China (English)

    Luhai LI; Ming WANG; Yi FANG; Shunan QIAO

    2009-01-01

    To avoid environmental pollution due to organic dye solutions, the electrophoresis and degradation of dye in organic solvents such as alcohol were investigated. Many dyes were tested in the Indium tin oxide (ITO) electrode driving cell, and about 15 dyes moved under voltage driving. Both the curves of ultraviolet-visible (UV-Vis) and infrared (IR) spectra of the electrophoresis samples showed that the metal complexes Red 04 and Acid Black 1 were degradable in alcohol solution by electrochemical reaction. The cyclic volt-ampere curves of the samples from the electrochemical working station proved that electrochemical reactions took place. Based on the analysis of UV-Vis and IR spectra, the electrochemical degradation products of azo and metal complex azo dyes at lower voltage driving (1-5 V) in organic solvents are oxidized azobenzene, not hydrazine, which was found in the electrochemical degradation of dye water solutions. When the ITO electrode is modified by a polyimide (PI) film to a thickness less than 4 μm, the electrochemical degradation of the dye in alcohol solution will not appear in the cyclic volt-ampere curves. A dye electrophoresis in organic solution flexible prototype e-paper display was formed and the display picture is shown.

  15. Influences of Organic Solvents on Particle Size and Drug-loading Efficiency for 5-Fluorouracil Poly(lactic acid) Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    LIUXiao-yan; CHANGJin; GUOYan-shuang; YUANXu-bo; LIXiao-rong; LIUChun-ling; SONGCun-xian

    2004-01-01

    The objective of this study was to investigate the influences of organic solvents on particle size, drug content, loading efficiency and yield for 5-Fluorouracil Poly (lactic acid) nanoparticles . The 5-Fluorouracil was entrapped into poly(lactic acid)(PLA) nanoparticles using a water-in-oil-in-water solvent evaporation technique. During the preparation process, ethyl acetate and acetone were used as organic solvents since they are less toxic than the more commonly used dichloromethane. The effect of the three solvents on particle size, drug content, loading efficiency and yield of nanopartcles was compared. When the solvent of the oil phase was acetone, the highest drug content, smallest particle size and lowest yield were obtained for the PLA nanoparticles.

  16. D{sub 2}O–H{sub 2}O solvent isotope effects on the enthalpy of 1,1,3,3-tetramethyl-2-thiourea hydration at temperatures from (278.15 to 313.15) K and ambient pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Evgeniy V., E-mail: evi_ihrras@mail.ru [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya St., 153045 Ivanovo (Russian Federation); Batov, Dmitriy V. [Incorporated Physical and Chemical Center of Solution Researches, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya St., 153045 Ivanovo (Russian Federation); Ivanovo’s State University of Chemistry and Technology, 7 Sheremetevsky Av., 153000 Ivanovo (Russian Federation); Abrosimov, V.K. [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya St., 153045 Ivanovo (Russian Federation)

    2014-08-20

    Highlights: • Enthalpies of solution of 1,1,3,3-tetramethyl-2-thiourea in H{sub 2}O and D{sub 2}O were measured. • Dissolution process becomes increasingly endothermic as the temperature is rising. • Enthalpy-isotopic effect undergoes a negative-to-positive sign inversion at 304 K. • Positive heat capacity of dissolution increases significantly, going from H{sub 2}O to D{sub 2}O. • Hydration of solute, being prevailingly hydrophobic, is weakened with temperature. - Abstract: The enthalpies of solution of 1,1,3,3-tetramethyl-2-thiourea (TMTU) in ordinary (H{sub 2}O) and heavy (D{sub 2}O) water were measured at (278.15, 283.15, 288.15, 298.15, and 313.15) K and atmospheric pressure. Standard molar enthalpies and heat capacities of solution and hydration, together with D{sub 2}O–H{sub 2}O solvent isotope effects (IEs) on these quantities, were calculated. It was established that, unlike the process of forming aqueous 1,1,3,3-tetramethyl-2-urea (TMU), the dissolution of TMTU in both H{sub 2}O and D{sub 2}O is an endothermic effect over the whole temperature range studied, and the standard enthalpy-isotopic effect undergoes a negative-to-positive sign inversion nearby of T = 304 K. Going from TMTU to TMU, the standard heat capacity of solution (hydration) and corresponding IE become less positive.

  17. 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

  18. Improved Production of Paclitaxel from Suspension Culture of Taxus chinensis var.mairei by in situ Extraction with Organic Solvents

    Institute of Scientific and Technical Information of China (English)

    未作君; 元英进; 吴兆亮; 吴金川

    2003-01-01

    The production of paclitaxel from suspension culture of Taxus chinensis var,mairei was improved by in situ extraction with organic solvents to avoid feedback repression and product degradation.Oleic acid and dibutyl phthalate were proved to be suitable solvents .The optimal volumetric percentage of organic solvents in the culture medium was found to be around 8%,and the favorable time for their introduction was at the exponential phase of cell growth,Paclitaxel production with the in situ extraction was ca 3-fold of that without extraction.

  19. Combined effects of exposure to occupational noise and mixed organic solvents on blood pressure in car manufacturing company workers.

    Science.gov (United States)

    Attarchi, Mirsaeed; Golabadi, Majid; Labbafinejad, Yasser; Mohammadi, Saber

    2013-02-01

    Recent studies suggest that occupational exposures such as noise and organic solvents may affect blood pressure. The aim of this study was to investigate interaction of noise and mixed organic solvents on blood pressure. Four hundred seventy-one workers of a car manufacturing plant were divided into four groups: group one or G1 workers exposed to noise and mixed organic solvents in the permitted limit or control group, G3 exposed to noise only, G2 exposed to solvents only, and G4 workers exposed to noise and mixed organic solvents at higher than the permitted limit or co-exposure group. Biological interaction of two variables on hypertension was calculated using the synergistic index. The workers of co-exposure group (G4), noise only group (G3), and solvents only group (G2) had significantly higher mean values of SBP and DBP than workers of control group (G1) or office workers (P car manufacturing company workers and co-exposure to noise and a mixture of solvents has an additive effect in this regard. Therefore appropriate preventive programs in these workers recommended. Copyright © 2012 Wiley Periodicals, Inc.

  20. Inactivation of enzymes by organic solvents: New technique with well-defined interfacial area

    Energy Technology Data Exchange (ETDEWEB)

    Ghatorae, A.S.; Bell, G.; Halling, P.J. (Univ. of Strathclyde, Glasgow (United Kingdom))

    1994-02-20

    A liquid-liquid bubble column apparatus allows exposure of enzyme solutions to water-immiscible organic solvents with a known total interfacial area and well-defined time scales and flow. It allows clear distinction of the different classes of inactivation mechanism. With urease as a model enzyme, octan-2-one and butylbenzene act only through the effects of solvent molecules dissolved in the aqueous phase, giving first-order inactivation at 0.34 and 0.21 h[sup [minus]1], respectively. Hexane and tridecane act only through exposure to the interface. The amount of urease inactivated is proportional to the total area of interface exposed, rather than to elapsed time, and may be characterized by a rate of about 0.5 [mu]kat m[sup [minus]2]. This is consistent with the formation and inactivation of a complete adsorbed monolayer of protein. With butan-1-ol, both mechanisms contribute significantly to the observed inactivation. The presence of O[sub 2] increases the rate of interfacial inactivation, but not that by dissolved solvent.

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

    Science.gov (United States)

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

    2017-02-01

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

  2. Enzymatic resolution of racemic amines in a continuous reactor in organic solvents.

    Science.gov (United States)

    Gutman, A L; Meyer, E; Kalerin, E; Polyak, F; Sterling, J

    1992-10-05

    An enzymatic process has been developed for the continuous production of the pharmaceutically important intermediate (R)-1-aminoindan and of the chiral resolving agent (R)-1-(1-naphthyl)ethylamine. The process consists of the subtilisin catalyzed stereoselective aminolysis of the racemic primary amine with an active ester in organic solvent. The competing nonenzymatic reaction has been suppressed by appropriate choice of solvent and reactant's concentration and by minimizing the time of contact between the amine and the active ester. Subtilisin was immobilized on glass beads and the reaction carried out in a continuous-flow column bioreactor. By using a 450-mL column bioreactor containing 5.7 g of subtilisin immobilized on 570 g of glass beads, 1.6 kg of racemic 1-(1-naphthyl)ethylamine was resolved after 320 h of continuous operation with only a slight loss of the enzymatic activity. During the whole process, the optical purity of the chiral amine eluting from the column was higher than 90%. A facile procedure was developed for separating the unreacted (R)-amine from the (S)-amide and for the recycling of the solvent 3-methyl-3-pentanol and the active ester 2,2,2-trifluoroethyl butyrate.

  3. Isolation and characterization of a novel thermophilic-organic solvent stable lipase from Acinetobacter baylyi.

    Science.gov (United States)

    Uttatree, Sasithorn; Winayanuwattikun, Pakorn; Charoenpanich, Jittima

    2010-11-01

    The benzene tolerant Acinetobacter baylyi isolated from marine sludge in Angsila, Thailand could constitutively secrete lipolytic enzymes. The enzyme was successfully purified 21.89-fold to homogeneity by ammonium sulfate precipitation and gel-permeable column chromatography with a relative molecular mass as 30 kDa. The enzyme expressed maximum activity at 60 degrees C and pH 8.0 with p-nitrophenyl palmitate as a substrate and found to be stable in pH and temperature ranging from 6.0-9.0 to 60-80 degrees C, respectively. A study on solvent stability revealed that the enzyme was highly resisted to many organic solvents especially benzene and isoamyl alcohol, but 40% inhibited by decane, hexane, acetonitrile, and short-chain alcohols. Lipase activity was completely inhibited in the presence of Fe(2+), Mn(2+), EDTA, SDS, and Triton X-100 while it was suffered detrimentally by Tween 80. The activity was enhanced by phenylmethylsulfonyl fluoride (PMSF), Na(+), and Mg(2+) and no significant effect was found in the presence of Ca(2+) and Li(+). Half of an activity was retained by Ba(2+), Ag(+), Hg(+), Ni(2+), Zn(2+), and DTT. The enzyme could hydrolyze a wide range of p-nitrophenyl esters, but preferentially medium length acyl chains (C(8)-C(12)). Among natural oils and fats, the enzyme 11-folds favorably catalyzed the hydrolysis of rice bran oil, corn oil, sesame oil, and coconut oil in comparison to palm oil. Moreover, the transesterification activity of palm oil to fatty acid methyl esters (FAMEs) revealed 31.64 +/- 1.58% after 48 h. The characteristics of novel A. baylyi lipase, as high temperature stability, organic solvent tolerance, and transesterification capacity from palm oil to FAMEs, indicate that it could be a vigorous biocatalyzer in the prospective fields as bioenergy industry or even in organic synthesis and pharmaceutical industry.

  4. Solvent extraction of scandium from lateritic nickel- cobalt ores using different organic reagents

    Directory of Open Access Journals (Sweden)

    Ferizoğlu Ece

    2016-01-01

    Full Text Available Scandium is the most important and strategic metal that can be recovered as a by-product from lateritic nickel-cobalt ores. In this research, different extractants were investigated in order to extract scandium from a sulfate medium by a using a solvent extraction method. Generally, the organic extractants are classified as acidic, neutral and basic organophosphorus compounds. However, in solvent extraction of scandium, the acidic and neutral organophosphorus compounds are preferred due to their higher extraction efficiencies. Thus, the aim of the present study was to compare the scandium extraction efficiencies of some acidic and neutral organic reagents. For this reason, Ionquest 290 (Bis(2,4,4-trimethylpenthyl phosphonic acid, DEHPA (Di(2-ethylhexyl phosphoric acid, Cyanex 272 ((Bis(2,4,4-trimethylpentyl phosphinic acid which are acidic organophosphorus compounds, and Cyanex 923 (Trialkylphosphine oxide, which is a neutral organophosphorus compound, were used. The extraction capacities of these organics were studied with respect to the extractant concentration at same pH and phase ratio. As a result of the study, DEHPA was found to have higher scandium extraction efficiency with lower iron extraction at pH = 0.55 at a phase ratio of 10:1 = A:O.

  5. SYNTHESIS AND CHARACTERIZATION OF CdSe COLLOIDAL QUANTUM DOTS IN ORGANIC SOLVENT

    OpenAIRE

    Ion Geru; Olga Bordian; Constantin Loshmansky; Ion Culeac; Constantin Turta

    2014-01-01

    In this paper we present experimental results on preparation and characterization of colloidal CdSe quantum dots in organic solvent. CdSe QDs were synthesized following a modified literature method. CdSe QDs were isolated by adding acetone to the cooled solution followed by centrifugation. CdSe QDs have been characterized by UV-Vis absorption and photoluminescent (PL) spectroscopy. The average CdSe particles size estimated from the UV-Vis absorption spectra was found to be in the rang...

  6. SYNTHESIS AND CHARACTERIZATION OF CdSe COLLOIDAL QUANTUM DOTS IN ORGANIC SOLVENT

    Directory of Open Access Journals (Sweden)

    Ion Geru

    2014-06-01

    Full Text Available In this paper we present experimental results on preparation and characterization of colloidal CdSe quantum dots in organic solvent. CdSe QDs were synthesized following a modified literature method. CdSe QDs were isolated by adding acetone to the cooled solution followed by centrifugation. CdSe QDs have been characterized by UV-Vis absorption and photoluminescent (PL spectroscopy. The average CdSe particles size estimated from the UV-Vis absorption spectra was found to be in the range 2.28-2.92 nm which is in good agreement with PL measurements.

  7. Resolution of 2-Octanol via Lipase-catalyzed Enantioselective Acetylation in Organic Solvents

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi; LI Zheng-qiang; Yu Da-hai; WENG Liang; LIU Ming; ZHANG Gui-rong; CAO Shu-gui

    2004-01-01

    The lipases from different sources were screened for their ability to catalyze the resolution of 2-octanol in organic solvents with vinyl acetate as the acylating reagent. The medium effect has been studied on the irreversible transesterification with varying water activity(aw). The influence of vinyl acetate concentration on it has also been investigated. Under the optimal conditions, the enantiomeric ratio(E value) of pseudomonas fluorescence lipase(PFL) exceeded 200 with an enantiomeric excess(e. e. ) of S-2-octanol above 99% at a 51% degree of conversion.

  8. Cation-π Interaction between the Aromatic Organic Counterion and DTAB Micelle in Mixed Solvents

    Institute of Scientific and Technical Information of China (English)

    DENG,Dong-Shun(邓东顺); LI,Hao-Ran(李浩然); LIU,Di-Xia(刘迪霞); HAN,Shi-Jun(韩世钧)

    2004-01-01

    The cation-π interaction between the aromatic organic counterion potassium hydrogen phthalate (KHP) and DTAB micelle in aqueous mixture of EG was investigated, using the techniques of conductivity measurements, UV absorption spectrum and NMR spectrum. The conductivity and UV spectrum studies were with respect to the effect of KHP on DTAB and that of DTAB micelle on KHP, respectively. According to the chemical shift changes of the aromatic ring and the surfactant methylene protons, it can be assumed that KHP penetrated into DTAB micelle with its carboxylic group protruding out of the micellar surface. And the strength of the interaction became weaker with the content of EG in the mixed solvent increasing.

  9. Effects of organic solvents on the enzyme activity of Trypanosoma cruzi glyceraldehyde-3-phosphate dehydrogenase in calorimetric assays

    DEFF Research Database (Denmark)

    Wiggers, Henrik; Cheleski, J; Zottis, A

    2007-01-01

    .0% for MeOH and up to 7.5% for DMSO. The results show that when GAPDH is assayed in the presence of DMSO (5%, v/v) using the ITC experiment, the enzyme exhibits approximately twofold higher activity than that of GAPDH with no cosolvent added. When MeOH (5%, v/v) is the cosolvent, the GAPDH activity...... is sixfold higher. The favorable effects of the organic solvents on the Michaelis-Menten enzyme-substrate complex formation ensure the consistency of the biological assays, structural integrity of the protein, and reproducibility over the measurement time. The reaction was also kinetically monitored......In drug discovery programs, dimethyl sulfoxide (DMSO) is a standard solvent widely used in biochemical assays. Despite the extensive use and study of enzymes in the presence of organic solvents, for some enzymes the effect of organic solvent is unknown. Macromolecular targets may be affected...

  10. Highly mesoporous metal-organic framework assembled in a switchable solvent

    Science.gov (United States)

    Peng, Li; Zhang, Jianling; Xue, Zhimin; Han, Buxing; Sang, Xinxin; Liu, Chengcheng; Yang, Guanying

    2014-07-01

    The mesoporous metal-organic frameworks are a family of materials that have pore sizes ranging from 2 to 50 nm, which have shown promising applications in catalysis, adsorption, chemical sensing and so on. The preparation of mesoporous metal-organic frameworks usually needs the supramolecular or cooperative template strategy. Here we report the template-free assembly of mesoporous metal-organic frameworks by using CO2-expanded liquids as switchable solvents. The mesocellular metal-organic frameworks with large mesopores (13-23 nm) are formed, and their porosity properties can be easily adjusted by controlling CO2 pressure. Moreover, the use of CO2 can accelerate the reaction for metal-organic framework formation from metal salt and organic linker due to the viscosity-lowering effect of CO2, and the product can be recovered through CO2 extraction. The as-synthesized mesocellular metal-organic frameworks are highly active in catalysing the aerobic oxidation of benzylic alcohols under mild temperature at atmospheric pressure.

  11. Thermodynamics of organic chemical hydration: QSPR models using physicochemical HYBOT descriptors.

    Science.gov (United States)

    Raevsky, O A; Liplavskiy, Y V; Raevskaya, O E; Mannhold, R

    2009-07-01

    Stable and predictive quantitative structure-property relationship (QSPR) models of thermodynamics of chemical hydration (changes in Gibbs energy, DeltaG(air/water), enthalpy, DeltaH(air/water) and entropy DeltaS(air/water)) were obtained on the basis of physicochemical descriptors calculated by the HYBOT program. The structurally diverse training set (n = 151) and test set (n = 37) included 13 mono-functional chemical classes. The applied HYBOT descriptors comprise molecular polarizability alpha (as a volume-related term), the sum of partial negative charges on all atoms in a molecule SigmaQ(-) (as an electrostatic term) and the sum of H-bond acceptor and donor factors SigmaC(a) and SigmaC(d) (as H-bond terms). Final equations for changes in Gibbs energy and enthalpy provided good statistical criteria and standard deviations on the level of errors of experimental determinations. All four above-mentioned terms essentially contribute to hydration enthalpy and each of them increases negative values of enthalpy. Hydration Gibbs energy predominantly depends on hydrogen bonding between solute and water molecules. Steric and electrostatic terms act in opposite directions and partly compensate each other. Changes in entropy correlate with increasing H-bond acceptor ability, whereas the other three descriptors exhibit inverse correlations.

  12. Organic solvent mediated self-association of an amyloid forming peptide from beta2-microglobulin: an atomic force microscopy study.

    Science.gov (United States)

    Chaudhary, Nitin; Singh, Shashi; Nagaraj, Ramakrishnan

    2008-01-01

    Human beta(2)-microglobulin (beta(2)m) forms amyloid fibrils in hemodialysis related amyloidosis. Peptides spanning the beta strands of beta(2)m have been shown to form amyloid fibrils in isolation. We have studied the self-association of a 13-residue peptide Ac-DWSFYLLYYTEFT-am (Pbeta(2)m) spanning one of the beta-strands of human beta(2)-microglobulin when dissolved in various organic solvents such as methanol (MeOH), trifluoroethanol (TFE), hexafluoroisopropanol (HFIP), and dimethylsulfoxide. We have observed that Pbeta(2)m forms amyloid fibrils when diluted from organic solvents into aqueous buffer at pH 7.0 as judged by increase in thioflavin T fluorescence. Fibril formation was observed to depend on the solvents in which peptide stock solutions were prepared. Circular dichroism spectra indicated propensity for helical conformation in MeOH, TFE, and HFIP. In buffer, beta-structure was observed irrespective of the solvent in which the peptide stock solutions were prepared. Atomic force microscopy images obtained by drying the peptide on mica from organic solvents indicated the ability of Pbeta(2)m to self-associate to form nonfibrillar structures. Morphology of the structures was dependent on the solvent in which the peptide was dissolved. Peptides that have the ability to self-associate such as amyloid-forming peptides would be attractive candidates for the generation of self-assembled structures with varying morphologies by appropriate choice of surfaces and solvents for dissolution. Copyright 2008 Wiley Periodicals, Inc.

  13. Effects of Organic Solvents for Composite Active Layer of PCDTBT/PC71BM on Characteristics of Organic Solar Cell Devices

    Directory of Open Access Journals (Sweden)

    Paik-Kyun Shin

    2014-01-01

    Full Text Available Bulk heterojunction (BHJ structure based active layers of PCDTBT/PC71BM were prepared by using different organic solvents for fabrication of organic solar cell (OSC devices. Mixture of precursor solutions of PCDTBT/PC71BM in three different organic solvents was prepared to fabricate composite active layers by spin-coating process: chloroform; chlorobenzene; o-dichlorobenzene. Four different blend ratios (1 : 3–1 : 6 of PCDTBT: PC71BM were adopted for each organic solvent to clarify the effect on the resulting OSC device characteristics. Surface morphology of the active layers was distinctively affected by the blend ratio of PCDTBT/PC71BM in organic solvents. Influence of the blend ratio of PCDTBT/PC71BM on the OSC device parameters was discussed. Performance parameters of the resulting OSC devices with different composite active layers were comparatively investigated. Appropriate blend ratio and organic solvent to achieve better OSC device performance were proposed. Furthermore, from the UV-Vis spectrum of each active layer prepared using the PCDTBT/PC71BM mixed solution dissolved with different organic solvents, a possibility that the nanophase separation structure inside their active layer could appear was suggested.

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

    Science.gov (United States)

    Farajtabar, Ali; Jaberi, Fatemeh; Gharib, Farrokh

    2011-12-01

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

  15. 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.

  16. Enhanced Enzymatic Synthesis of a Cephalosporin, Cefadroclor, in the Presence of Organic Co-solvents.

    Science.gov (United States)

    Liu, Kun; Li, Sha; Pang, Xiao; Xu, Zheng; Li, Dengchao; Xu, Hong

    2017-05-01

    In this study, we investigated the enzymatic synthesis of a semi-synthetic cephalosporin, cefadroclor, from 7-aminodesacetoxymethyl-3-chlorocephalosporanic acid (7-ACCA) and p-OH-phenylglycine methyl ester (D-HPGM) using immobilized penicillin G acylase (IPA) in organic co-solvents. Ethylene glycol (EG) was employed as a component of the reaction mixture to improve the yield of cefadroclor. EG was found to increase the yield of cefadroclor by 15-45%. An investigation of altered reaction parameters including type and concentration of organic solvents, pH of reaction media, reaction temperature, molar ratio of substrates, enzyme loading, and IPA recycling was carried out in the buffer mixture. The best result was a 76.5% conversion of 7-ACCA, which was obtained from the reaction containing 20% EG (v/v), D-HPGM to 7-ACCA molar ratio of 4:1 and pH 6.2, catalyzed by 16 IU mL(-1) IPA at 20 °C for 10 h. Under the optimum conditions, no significant loss of IPA activity was found after seven repeated reaction cycles. In addition, cefadroclor exhibited strong inhibitory activity against yeast, Bacillus subtilis NX-2, and Escherichia coli and weaker activity against Staphylococcus aureus and Pseudomonas aeruginosa. Cefadroclor is a potential antibiotic with activity against common pathogenic microorganisms.

  17. Response of Rhodococcus erythropolis strain IBBPo1 to toxic organic solvents

    Directory of Open Access Journals (Sweden)

    Mihaela Marilena Stancu

    2015-12-01

    Full Text Available Abstract Recently, there has been a lot of interest in the utilization of rhodococci in the bioremediation of petroleum contaminated environments. This study investigates the response of Rhodococcus erythropolis IBBPo1 cells to 1% organic solvents (alkanes, aromatics. A combination of microbiology, biochemical, and molecular approaches were used to examine cell adaptation mechanisms likely to be pursued by this strain after 1% organic solvent exposure. R. erythropolis IBBPo1 was found to utilize 1% alkanes (cyclohexane, n-hexane, n-decane and aromatics (toluene, styrene, ethylbenzene as the sole carbon source. Modifications in cell viability, cell morphology, membrane permeability, lipid profile, carotenoid pigments profile and 16S rRNA gene were revealed in R. erythropolis IBBPo1 cells grown 1 and 24 h on minimal medium in the presence of 1% alkanes (cyclohexane, n-hexane, n-decane and aromatics (toluene, styrene, ethylbenzene. Due to its environmental origin and its metabolic potential, R. erythropolis IBBPo1 is an excellent candidate for the bioremediation of soils contaminated with crude oils and other toxic compounds. Moreover, the carotenoid pigments produced by this nonpathogenic Gram-positive bacterium have a variety of other potential applications.

  18. Cytotoxic effect of organic solvents and surfactant agents on Acanthamoeba castellanii cysts.

    Science.gov (United States)

    Ezz Eldin, Hayam Mohamed; Sarhan, Rania Mohamed

    2014-05-01

    Acanthamoeba castellanii is a protozoan parasite that may cause sight-threatening keratitis in some individuals. Its eradication is difficult because the trophozoites encyst making organisms highly resistant to anti-amoebic drugs. To test new anti-Acanthamoeba agents, usually having low water solubility, organic solvents and surfactant agents should be used. Therefore, the lethal effect of different concentrations of the solvents acetone, methanol, ethanol, and DMSO and surfactant agents Tween 20, Tween 80, and Triton X-100 was tested. The minimal inhibitory concentrations (MIC) were determined against Acanthamoeba cysts. Results of the present study showed that the MIC for ethanol, methanol, acetone and DMSO was 25, 12.5, 12.5, and 10%, respectively and for Tween 20, Tween 80, and Triton X-100 was 0.25, 0.06, and 0.03%, respectively. There was no significant inhibitory effect on the multiplication of Acanthamoeba cysts as compared to parasite control when using the concentrations 3.12% for ethanol, 1.6% for methanol and acetone, 1.25% for DMSO, and 0.016% for Tween 20. On the other hand, both Tween 80 and Triton X-100 showed highly significant difference in comparison to parasite control almost among all the range of concentrations used in this study, and both showed lethal effect of 19 and 27.2%, respectively at their least concentration.

  19. Enantioselective hydrolysis of epichlorohydrin using whole Aspergillus niger ZJB-09173 cells in organic solvents

    Indian Academy of Sciences (India)

    Huo-Xi Jin; Zhong-Ce Hu; Yu-Guo Zheng

    2012-09-01

    The enantioselective hydrolysis of racemic epichlorohydrin for the production of enantiopure ()-epichloro-hydrin using whole cells of Aspergillus niger ZJB-09173 in organic solvents was investigated. Cyclohexane was used as the reaction medium based on the excellent enantioselectivity of epoxide hydrolase from A. niger ZJB-09173 in cyclohexane. However, cyclohexane had a negative effect on the stability of epoxide hydrolase from A. niger ZJB-09173. In the cyclohexane medium, substrate inhibition, rather than product inhibition of catalysis, was observed in the hydrolysis of racemic epichlorohydrin using A. niger ZJB-09173. The racemic epichlorohydrin concentration was markedly increased by continuous feeding of substrate without significant decline of the yield. Ultimately, 18.5% of ()-epichlorohydrin with 98% enantiomeric excess from 153.6 mM of racemic epichlorohydrin was obtained by the dry cells of A. niger ZJB-09173, which was the highest substrate concentration in the production of enantiopure ()-epichlorohydrin by epoxide hydrolases using an organic solvent medium among the known reports.

  20. Synthesis of alkyl esters by cutinase in miniemulsion and organic solvent media.

    Science.gov (United States)

    de Barros, Dragana P C; Fonseca, Luís P; Cabral, Joaquim M S; Weiss, Clemens K; Landfester, Katharina

    2009-05-01

    The main objective of this work was studying and testing the nature and influence of reaction media (organic solvent vs. miniemulsion system) on the synthesis of alkyl esters catalyzed by Fusarium solani pisi cutinase. Ester synthesis and cutinase selectivity for different chain length of acids and alcohols (ethyl and hexyl) were evaluated. In iso-octane, after 1 h of reaction, cutinase exhibits rates of esterification between 0.24 micromol x mg(-)1 x min(-1) for ethyl oleate and 1.15 micromol x mg(-)1 x min(-1) for ethyl butyrate, while in a miniemulsion system the rates were from 0.05 for ethyl heptanoate to 0.76 micromol x mg(-1) x min(-1) for ethyl decanoate. The reaction rate for the synthesis of hexyl esters in a miniemulsion system was from 0.19 for hexyl heptanoate to 1.07 micromol x mg(-)1 x min(-1) for hexyl decanoate. High conversion yields of 95% at equilibrium after 8 h of reaction in iso-octane for pentanoic acid (C(5)) with ethanol at equimolar concentration (0.1 M) was achieved. Additionally, this work showed that a significant and unexpected shift in cutinase selectivity occurred towards longer chain length carboxylic acids (C(8)-C(10)) in miniemulsion system as compared to organic solvent (iso-octane) and previous studies in reverse micellar systems. The possibility of working with higher concentration of substrates, without inhibitory effect on the enzyme, was another advantage of the miniemulsion system.

  1. Scalable organic solvent free supercritical fluid spray drying process for producing dry protein formulations.

    Science.gov (United States)

    Nuchuchua, O; Every, H A; Hofland, G W; Jiskoot, W

    2014-11-01

    In this study, we evaluated the influence of supercritical carbon dioxide (scCO2) spray drying conditions, in the absence of organic solvent, on the ability to produce dry protein/trehalose formulations at 1:10 and 1:4 (w/w) ratios. When using a 4L drying vessel, we found that decreasing the solution flow rate and solution volume, or increasing the scCO2 flow rate resulted in a significant reduction in the residual water content in dried products (Karl Fischer titration). The best conditions were then used to evaluate the ability to scale the scCO2 spray drying process from 4L to 10L chamber. The ratio of scCO2 and solution flow rate was kept constant. The products on both scales exhibited similar residual moisture contents, particle morphologies (SEM), and glass transition temperatures (DSC). After reconstitution, the lysozyme activity (enzymatic assay) and structure (circular dichroism, HP-SEC) were fully preserved, but the sub-visible particle content was slightly increased (flow imaging microscopy, nanoparticle tracking analysis). Furthermore, the drying condition was applicable to other proteins resulting in products of similar quality as the lysozyme formulations. In conclusion, we established scCO2 spray drying processing conditions for protein formulations without an organic solvent that holds promise for the industrial production of dry protein formulations.

  2. Occupational exposure to organic solvents: a risk factor for pulmonary veno-occlusive disease.

    Science.gov (United States)

    Montani, David; Lau, Edmund M; Descatha, Alexis; Jaïs, Xavier; Savale, Laurent; Andujar, Pascal; Bensefa-Colas, Lynda; Girerd, Barbara; Zendah, Inès; Le Pavec, Jerome; Seferian, Andrei; Perros, Frédéric; Dorfmüller, Peter; Fadel, Elie; Soubrier, Florent; Sitbon, Oliver; Simonneau, Gérald; Humbert, Marc

    2015-12-01

    Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension characterised by predominant remodelling of pulmonary venules. Bi-allelic mutations in the eukaryotic translation initiation factor 2α kinase 4 (EIF2AK4) gene were recently described as the major cause of heritable PVOD, but risk factors associated with PVOD remain poorly understood. Occupational exposures have been proposed as a potential risk factor for PVOD, but epidemiological studies are lacking.A case-control study was conducted in consecutive PVOD (cases, n=33) and pulmonary arterial hypertension patients (controls, n=65). Occupational exposure was evaluated via questionnaire interview with blinded assessments using an expert consensus approach and a job exposure matrix (JEM).Using the expert consensus approach, PVOD was significantly associated with occupational exposure to organic solvents (adjusted OR 12.8, 95% CI 2.7-60.8), with trichloroethylene being the main agent implicated (adjusted OR 8.2, 95% CI 1.4-49.4). JEM analysis independently confirmed the association between PVOD and trichloroethylene exposure. Absence of significant trichloroethylene exposure was associated with a younger age of disease (54.8±21.4 years, p=0.037) and a high prevalence of harbouring bi-allelic EIF2AK4 mutations (41.7% versus 0%, p=0.015).Occupational exposure to organic solvents may represent a novel risk factor for PVOD. Genetic background and environmental exposure appear to influence the phenotypic expression of the disease.

  3. Use of Organic Solvents to Extract Organochlorine Pesticides (OCPs) from Aged Contaminated Soils

    Institute of Scientific and Technical Information of China (English)

    YE Mao; JIN Xin; JIANG Xin; YANG Xing-Lun; SUN Ming-Ming; BIAN Yong-Rong; WANG Fang; GU Cheng-Gang; WEI Hai-Jiang; SONG Yang; WANG Lei

    2013-01-01

    Problems associated with organochlorine pesticide (OCP)-contaminated sites in China have received wide attention.To solve such problems,innovative ex-situ methods of site remediation are urgently needed.We investigated the feasibility of the extraction method with different organic solvents,ethanol,1-propanol,and three fractions of petroleum ether,using a soil collected from Wujiang (WJ),China,a region with long-term contamination of dichlorodiphenyltrichloroethanes (DDTs).We evaluated different influential factors,including organic solvent concentration,washing time,mixing speed,solution-to-soil ratio,and washing temperature,on the removal of DDTs from the WJ soil.A set of relatively better parameters were selected for extraction with 100 mL L-1 petroleum ether (60-90 ℃):washing time of 180 min,mixing speed of 100 r min-1,solution-to-soil ratio of 10:1,and washing temperature of 50 ℃.These selected parameters were also applied on three other seriously OCP-polluted soils.Results demonstrated their broad-spectrum effectiveness and excellent OCP extraction performance on the contaminated soils with different characteristics.

  4. Evaluation of the Process of Solvent Vapor Annealing on Organic Thin Films

    KAUST Repository

    Ren, Yi

    2011-07-01

    Solvent vapor annealing has recently emerged as an intriguing, room-temperature, and highly versatile alternative to thermal annealing. The chemically selective interaction between solvents and organic semiconductors opens new opportunities to selectively anneal certain components of the device, while leaving others intact. On the downside, these interactions are complex and rather unpredictable, requiring further investigation. We propose a novel methodology to investigate solvent-film interactions, based on use of an in situ quartz crystal microbalance with dissipation (QCM-D) capability and in situ grazing incidence wide angle X-ray scattering (GIWAXS). These methods make it possible to investigate both qualitatively and quantitatively the solvent vapor uptake, the resulting softening and changes (reversible and/or irreversible) in crystallinity. Using this strategy, we have investigated the solvent vapor annealing of traditional donor and acceptor materials, namely poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM). We find these materials retain their rigid structure during toluene vapor annealing and do not dewet. We also investigated the toluene vapor annealing of several newly proposed acceptor molecules (pentacene-based) modified with various silyl groups and electron withdrawing groups to tune the packing structure of the acceptor domains and energy levels at the donor-acceptor interface. We found a dramatic effect of the electron-withdrawing group on vapor uptake and whether the film remains rigid, softens, or dissolves completely. In the case of trifluoromethyl electron-withdrawing group, we found the film dissolves, resulting in complete and irreversible loss of long range order. By contrast, the cyano group prevented loss of long range order, instead promoting crystallization in some cases. The silyl groups had a secondary effect in comparison to these. In the last part of the thesis, we investigated the

  5. Modeling the temperature dependent interfacial tension between organic solvents and water using dissipative particle dynamics.

    Science.gov (United States)

    Mayoral, E; Goicochea, A Gama

    2013-03-07

    The interfacial tension between organic solvents and water at different temperatures is predicted using coarse-grained, mesoscopic Dissipative Particle Dynamics (DPD) simulations. The temperature effect of the DPD repulsive interaction parameters, aij, for the different components is calculated from the dependence of the Flory-Huggins χ parameter on temperature, by means of the solubility parameters. Atomistic simulations were carried out for the calculation of the solubility parameters for different organic compounds at different temperatures in order to estimate χ and then the aij coefficients. We validate this parametrization through the study of the interfacial tension in a mixture of benzene and water, and cyclohexane and water, varying the temperature. The predictions of our simulations are found to be in good agreement with experimental data taken from the literature, and show that the use of the solubility parameter at different temperatures to obtain the repulsive DPD parameters is a good alternative to introduce the effect of temperature in these systems.

  6. Tryptophanase from Escherichia coli: catalytic and spectral properties in water-organic solvents.

    Science.gov (United States)

    Faleev, N G; Dementieva, I S; Zakomirdina, L N; Gogoleva, O I; Belikov, V M

    1994-08-01

    In water-methanol and water-dimethylformamide (DMF) (1:1 v/v) solutions tryptophanase from E.coli retains its abilities to form a quinonoid complex with quasisubstrates and to catalyze the decomposition of S-o-nitrophenyl-L-cysteine (SOPC). Both the KM and Vmax values decrease in water-organic media. The affinities of tryptophanase for L-alanine, L-tryptophan, oxindolyl-L-alanine and indole in aqueous methanol are decreased, the effect being stronger for the more hydrophobic substances. In a water solution tryptophanase catalizes the reaction of SOPC with indole to form L-tryptophan while in water-organic solvents only decomposition of SOPC is observed.

  7. Comparative Physical properties of Karanj Seed Oil by Using Different Organic Solvents: an Environmental Viable Fuel

    Directory of Open Access Journals (Sweden)

    *Savita Sagwan

    2016-04-01

    Full Text Available Oil yielding crop plants are very important for economic growth of the energy and agricultural sectors. The oil seeds containing polyunsaturated fatty acids are important source of biodiesel. These organic seed oils are better than diesel fuels in terms of physico-chemical properties and biodegradability. One such plant species is Pongamia pinnata belonging to family Fabaceae. It is drought resistant, semi-deciduous, nitrogen fixing leguminous tree. It grows about 15-20 meters in height with a large canopy which spreads equally wide. Detail physical study in different organic solvents (n-Hexane, ethyl acetate and petroleum ether intends to identify all advantages and disadvantages of pongamia pinnata as a sustainable feedstock for the production of Biodiesel equivalent to fossil fuel as per ASTM.

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

    OpenAIRE

    YOUNGJUNE ePARK; Kun-Yi Andrew eLin; Ah-Hyung Alissa Park; Camille ePetit

    2015-01-01

    CO2 capture by amine scrubbing, which has a high CO2 capture capacity and a rapid reaction rate, is the most employed and investigated approach to date. There are a number of recent large-scale demonstrations including the Boundary Dam Carbon Capture Project by SaskPower in Canada that have reported successful implementations of aqueous amine solvent in CO2 capture from flue gases. The findings from these demonstrations will significantly advance the field of CO2 capture in the coming years. ...

  9. Effects of Occupational Exposure with Mixture of Aromatic Organic Solvents on Liver Enzymes in Workers of an Automobile Plant

    Directory of Open Access Journals (Sweden)

    MS Attarchi

    2009-10-01

    Full Text Available Introduction & Objective: Organic solvents have a broad range of application in industry. Hepatotoxicity of different organic halogenated solvents like carbon tetrachloride has been verified in numerous studies however, studies investigating the association between the occupational exposure with aromatic organic solvents like benzene, toluene & xylene and hepatic toxicity are limited. The goal of this study was to review the long term effects of exposure with mixture of aromatic organic solvents, in higher amounts of permissible level, on hepatic system. Materials & methods: This is a cross sectional study which was conducted in an automobile plant. Workers employed in the painting saloon were considered as cases and workers in assembly as controls. A questionnaire, containing demographic data like age and years of employment, was completed for each of 349 workers. After considering exclusion criteria, liver enzyme level (AST, ALT & ALP of 163 case workers was compared with 186 controls. Concentration of mixture of organic solvents in painting saloon was twice and a half as much of the permissible level. The collected data was analyzed by the SPSS software, using T score, K2 and Linear Regression. Results: The Mean level of ALP in case group was significantly higher than the control group (P<0.001. For AST and ALT the mean was higher in the case group but this difference was not statistically significant. Increase in ALP level had a significant association with BMI (P<0.001 and smoking (P=0.007 yet, no significant relation was seen with age and years of employment. Conclusion: Our study suggested that exposure with mixture of aromatic organic solvents, in higher amounts of permissible level, can cause mild functional liver damage (cholestatic type. So, it is recommended to use liver function tests, especially ALP, for screening of workers exposed to mixture of aromatic organic solvents, for preliminary detection of hepatic dysfunction.

  10. Efficient production of fatty acid methyl ester from waste activated bleaching earth using diesel oil as organic solvent.

    Science.gov (United States)

    Kojima, Seiji; Du, Dongning; Sato, Masayasu; Park, Enoch Y

    2004-01-01

    Fatty acid methyl ester (FAME) production from waste activated bleaching earth (ABE) discarded by the crude oil refining industry was investigated using fossil fuel as a solvent in the esterification of triglycerides. Lipase from Candida cylindracea showed the highest stability in diesel oil. Using diesel oil as a solvent, 3 h was sufficient to obtain a yield of approximately 100% of FAME in the presence of 10% lipase from waste ABE. Kerosene was also a good solvent in the esterification of triglycerides embedded in the waste ABE. Fuel analysis showed that the FAME produced using diesel oil as a solvent complied with the Japanese diesel standard and the 10% residual carbon amount was lower than that of FAME produced using other solvents. Use of diesel oil as solvent in the FAME production from the waste ABE simplified the process, because there was no need to separate the organic solvent from the FAME-solvent mixture. These results demonstrate a promising reutilization method for the production of FAME, for use as a biodiesel, from industrial waste resources containing waste vegetable oils.

  11. (Liquid + liquid) equilibria in ternary aqueous mixtures of phosphoric acid with organic solvents at T = 298.2 K

    Energy Technology Data Exchange (ETDEWEB)

    Ghanadzadeh, H., E-mail: hggilani@guilan.ac.i [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of); Department of Chemical Engineering, University of Guilan, Rasht (Iran, Islamic Republic of); Ghanadzadeh, A., E-mail: aggilani@guilan.ac.i [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of); Aghajani, Z.; Abbasnejad, S.; Shekarsaraee, S. [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of)

    2010-06-15

    (Liquid + liquid) equilibrium (LLE) data for the ternary mixtures of left bracewater (1) + phosphoric acid (2) + organic solvents (3)right brace were determined at T = 298.2 K and atmospheric pressure. The organic solvents were cyclohexane, 2-methyl-2-butanol (tert-amyl alcohol), and isobutyl acetate. All the investigated systems exhibit Type-1 behaviour of LLE. The immiscibility region was found to be larger for the (water + phosphoric acid + cyclohexane) ternary system. The experimental LLE results were correlated with the NRTL model, and the binary interaction parameters were obtained. The reliability of the experimental tie-line results was tested through the Othmer-Tobias and Bachman correlation equations. Distribution coefficients and separation factors were evaluated over the immiscibility regions and a comparison of the extracting capabilities of the solvents was made with respect to these factors. The experimental results indicate the superiority of cyclohexane as the preferred solvent for the extraction of phosphoric acid from its aqueous solutions.

  12. Recrystallization and shape control of crystals of the organic dye acid green 27 in a mixed solvent.

    Science.gov (United States)

    Cong, Huai-Ping; Yu, Shu-Hong

    2007-01-01

    Recrystallization of the unstructured dye acid green 27 (AG27) in a mixed solvent of alcohol (ethanol or methanol) and water was systematically studied. The results demonstrated that AG27 crystals with uniform sizes and controllable shapes can be produced by simply changing the volume ratio of ethanol (or methanol) and deionized water (DIW). Rodlike and shuttlelike AG27 crystals can be selectively synthesized. The XRD analyses revealed the periodic structures of the organic crystals. Furthermore, crystallization in another mixed solvent of N,N-dimethylformamide (DMF) and DIW results in the formation of longer fibers with high aspect ratio, which further validates the remarkable effects of mixed solvent on the shape of the AG27 crystals. This method of recrystallization in a mixed solvent is expected to facilitate the synthesis of other functional organic crystals with unusual shapes.

  13. Minimum amount of extracting solvent of AB/BC countercurrent extraction separation using organic feed

    Institute of Scientific and Technical Information of China (English)

    程福祥; 吴声; 张玻; 刘艳; 王嵩龄; 廖春生; 严纯华

    2014-01-01

    For an AB/BC countercurrent extraction separation using organic feed, the conditions to have minimum amount of ex-tracting solvent (Smin) and minimum amount of scrubbing agent solution (Wmin) were discussed, and the formulae of bothSmin and Wmin were deduced. It was shown that only when the ratio of flowrate of central component B leaving aqueous outlet to that leaving organic outlet took a certain optimal value, the AB/BC separation could have Smin as well asWmin, and this optimal ratio was decided by the separation factors between the three components but independent of feed composition.Smin was only relative to the separation factor of A/C pair but regardless of the separation factors of other pairs as well as feed composition, whereasWmin was determined by the separation factors between the components together with feed composition. Meanwhile it was also found that the organic stream out of feed stage was same composition as the initial organic feed when the separation system was given by the two minimum amounts and its steady state was achieved. Finally the results above were used to design a LuYb/YbTm separation case and the stage-wise compositions of each component in both the organic and the aqueous phase at steady state were given by computer simulation.

  14. Nickel-Catalyzed Suzuki–Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory

    OpenAIRE

    Hie, Liana; Chang, Jonah J.; Garg, Neil K.

    2014-01-01

    A modern undergraduate organic chemistry laboratory experiment involving the Suzuki–Miyaura coupling is reported. Although Suzuki–Miyaura couplings typically employ palladium catalysts in environmentally harmful solvents, this experiment features the use of inexpensive nickel catalysis, in addition to a “green” alcohol solvent. The experiment employs heterocyclic substrates, which are important pharmaceutical building blocks. Thus, this laboratory procedure exposes students to a variety of co...

  15. Thermodynamic Stability Analysis of Tolbutamide Polymorphs and Solubility in Organic Solvents.

    Science.gov (United States)

    Svärd, Michael; Valavi, Masood; Khamar, Dikshitkumar; Kuhs, Manuel; Rasmuson, Åke C

    2016-06-01

    Melting temperatures and enthalpies of fusion have been determined by differential scanning calorimetry (DSC) for 2 polymorphs of the drug tolbutamide: FI(H) and FV. Heat capacities have been determined by temperature-modulated DSC for 4 polymorphs: FI(L), FI(H), FII, FV, and for the supercooled melt. The enthalpy of fusion of FII at its melting point has been estimated from the enthalpy of transition of FII into FI(H) through a thermodynamic cycle. Calorimetric data have been used to derive a quantitative polymorphic stability relationship between these 4 polymorphs, showing that FII is the stable polymorph below approximately 333 K, above which temperature FI(H) is the stable form up to its melting point. The relative stability of FV is well below the other polymorphs. The previously reported kinetic reversibility of the transformation between FI(L) and FI(H) has been verified using in situ Raman spectroscopy. The solid-liquid solubility of FII has been gravimetrically determined in 5 pure organic solvents (methanol, 1-propanol, ethyl acetate, acetonitrile, and toluene) over the temperature range 278 to 323 K. The ideal solubility has been estimated from calorimetric data, and solution activity coefficients at saturation in the 5 solvents determined. All solutions show positive deviation from Raoult's law, and all van't Hoff plots of solubility data are nonlinear. The solubility in toluene is well below that observed in the other investigated solvents. Solubility data have been correlated and extrapolated to the melting point using a semiempirical regression model.

  16. Solvent extraction of organic acids from stillage for its re-use in ethanol production process.

    Science.gov (United States)

    Castro, G A; Caicedo, L A; Alméciga-Díaz, C J; Sanchez, O F

    2010-06-01

    Stillage re-use in the fermentation stage in ethanol production is a technique used for the reduction of water and fermentation nutrients consumption. However, the inhibitory effect on yeast growth of the by-products and feed components that remains in stillage increases with re-use and reduces the number of possible recycles. Several methods such as ultrafiltration, electrodialysis and advanced oxidation processes have been used in stillage treatment prior its re-use in the fermentation stage. Nevertheless, few studies evaluating the effect of solvent extraction as a stillage treatment option have been performed. In this work, the inhibitory effect of serial stillage recycling over ethanol and biomass production was determined, using acetic acid as a monitoring compound during the fermentation and solvent extraction process. Raw palm oil methyl ester showed the highest acetic acid extraction from the aqueous phase, presenting a distribution coefficient of 3.10 for a 1:1 aqueous phase mixture:solvent ratio. Re-using stillage without treatment allowed up to three recycles with an ethanol production of 53.7 +/- 2.0 g L(-1), which was reduced 25% in the fifth recycle. Alternatively, treated stillage allowed up to five recycles with an ethanol final concentration of 54.7 +/- 1.3 g L(- 1). These results show that reduction of acetic acid concentration by an extraction process with raw palm oil methyl ester before re-using stillage improves the number of recycles without a major effect on ethanol production. The proposed process generates a palm oil methyl ester that contains organic acids, among other by-products, that could be used for product recovery and as an alternative fuel.

  17. Why do Hydrates (Solvates) Form in Small Neutral Organic Molecules? Exploring the Crystal Form Landscapes of the Alkaloids Brucine and Strychnine.

    Science.gov (United States)

    Braun, Doris E; Griesser, Ulrich J

    2016-11-02

    Computational methods were used to generate and explore the crystal structure landscapes of the two alkaloids strychnine and brucine. The computed structures were analyzed and rationalized by correlating the modelling results to a rich pool of available experimental data. Despite their structural similarity, the two compounds show marked differences in the formation of solid forms. For strychnine only one anhydrous form is reported in the literature and two new solvates from 1,4-dioxane were detected in the course of this work. In contrast, 22 solid forms are so far known to exist for brucine, comprising two anhydrates, four hydrates (HyA - HyC and a 5.25-hydrate), twelve solvates (alcohols and acetone) and four heterosolvates (mixed solvates with water and alcohols). For strychnine it is hard to produce any solid form other than the stable anhydrate while the formation of specific solid state forms of brucine is governed by a complex interplay between temperature and relative humidity/water activity and it is rather a challenging to avoid hydrate formation. Differences in crystal packing and the high tendency for brucine to form hydrates are not intuitive from the molecular structure alone, as both molecules have hydrogen bond acceptor groups but lack hydrogen bond donor groups. Only the evaluation of the crystal energy landscapes, in particular the close-packed crystal structures and high-energy open frameworks containing voids of molecular (water) dimensions, allowed us to unravel the diverse solid state behavior of the two alkaloids at a molecular level. In this study we demonstrate that expanding the analysis of anhydrate crystal energy landscapes to higher energy structures and calculating the solvent-accessible volume can be used to estimate non-stoichiometric or channel hydrate (solvate) formation, without explicitly computing the hydrate/solvate crystal energy landscapes.

  18. Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuqing, E-mail: yqzhang@public1.sz.js.cn; Shen Weide; Xiang Ruli [Soochow University, Silk Biotechnol. Lab., School of Life Science (China); Zhuge Lanjian; Gao Weijian; Wang Wenbao [Soochow University, Analytical Center (China)

    2007-10-15

    When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form (Silk I) into anti-parallel {beta}-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, {sup 13}C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with {beta}-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular

  19. Stabilization of Rocky Flats combustible residues contaminated with plutonium metal and organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, S.M.; Cisneros, M.R.; Jacobson, L.L.; Schroeder, N.C.; Ames, R.L.

    1998-09-30

    This report describes tests on a proposed flowsheet designed to stabilize combustible residues that were generated at the Rocky Flats Environmental Technology Site (RFETS) during the machining of plutonium metal. Combustible residues are essentially laboratory trash contaminated with halogenated organic solvents and plutonium metal. The proposed flowsheet, designed by RFETS, follows a glovebox procedure that includes (1) the sorting and shredding of materials, (2) a low temperature thermal desorption of solvents from the combustible materials, (3) an oxidation of plutonium metal with steam, and (4) packaging of the stabilized residues. The role of Los Alamos National Laboratory (LANL) in this study was to determine parameters for the low temperature thermal desorption and steam oxidation steps. Thermal desorption of carbon tetrachloride (CCl{sub 4}) was examined using a heated air stream on a Rocky Flats combustible residue surrogate contaminated with CCl{sub 4}. Three types of plutonium metal were oxidized with steam in a LANL glovebox to determine the effectiveness of this procedure for residue stabilization. The results from these LANL experiments are used to recommend parameters for the proposed RFETS stabilization flowsheet.

  20. Engymatic synthesis of aspartame precursor in organic solvent; Yuki yobaichu deno asuparutemu zenkutai no koso gosei

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, K. [Okayama Univ., Okayama (Japan). Faculty of Engineering

    1996-11-05

    Taking up the synthetic reaction of the precursor of artificial sweetener aspartame for which thermolysin is used as the catalyst, the features and problems of enzymatic reaction in organic solvent are discussed. It is found that immobilized enzyme which has high activity and stability can be prepared by adsorbing high concentration thermolysin in Amberlite XAD7 followed by bridge immobilization. The initial rate of the synthesis and the stability of immobilized enzyme depend on the types of solvents. Continuous reaction is attempted using a columnar ferment reactor (PFR) in ethyl acetate at the beginning, but the yield decreases in a short period because the immobilized enzyme lose its activity gradually from the upper area of the column where Z-Asp concentration is high. When CSTR (complete mixed type reactor) is used, deactivation of immobilized enzyme can be restricted because low Z-Asp concentration in the reactor can be maintained. It is demonstrated that continuous reaction of longer than 200 hours is possible although the reaction rate is as low as 90%. 4 refs., 3 figs., 1 tab.

  1. Crosslinked poly(ether block amide) composite membranes for organic solvent nanofiltration applications

    KAUST Repository

    Aburabie, Jamaliah

    2016-10-01

    Poly(ether block amide) – Pebax® – based membranes are well described for gas separation applications. But only a few publications exist for their application in pressure driven liquid applications like ultrafiltration and nanofiltration. Here we use the commercially available Pebax® 1657 for the preparation of membranes for the filtration of organic solvents. Porous polyacrylonitrile membranes were coated with Pebax® 1657 which was then crosslinked. Toluene diisocyanate (TDI) was used as a crosslinker agent for the coating. Reaction time and crosslinker concentration were optimized for the aimed application. The Pebax® coating and the impact of the TDI on the resulting crosslinked membranes were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). SEM analysis shows a uniform thin coating of the PEBAX that covers the pores of the PAN membranes. FTIR and DSC analysis confirm the crosslinking reaction. Crosslinked Pebax® membranes show high stability toward ethanol propanol, acetone and even dimethylformamide (DMF). In the case of DMF applications, the standard PAN was replaced by crosslinked PAN developed in our laboratory. In order to increase the membranes permeances, graphene oxide (GO) nanosheets were incorporated in the Pebax® coating. These GO containing membranes showed strongly increased permeances for selected solvents. © 2016 Elsevier B.V.

  2. Important factors influencing molecular weight cut-off determination of membranes in organic solvents

    NARCIS (Netherlands)

    Zwijnenberg, Harmen Jan; Dutczak, S.M.; Boerrigter, M.E.; Hempenius, Mark A.; Luiten-Olieman, Maria W.J.; Benes, Nieck Edwin; Wessling, Matthias; Stamatialis, Dimitrios

    2012-01-01

    In solvent resistant nanofiltration (SRNF), sensible selection of a membrane for a particular solvent/solute system is recognized as challenging. Prospective methods for suitability analysis of membranes include molecular weight cut off (MWCO) characterization. However, insufficient understanding of

  3. Pregnancy outcome after risk assessment of occupational exposure to organic solvents: a prospective cohort study.

    Science.gov (United States)

    Testud, François; D'Amico, Andrea; Lambert-Chhum, Rachel; Garayt, Christelle; Descotes, Jacques

    2010-11-01

    A rational medical, occupational and toxicological approach is instrumental to select objectively among pregnant women exposed to chemicals at the workplace those who should be withdrawn or benefit from improvements of working conditions. Risk assessment is based on a comprehensive review of compounds' hazards and a thorough evaluation of the actual exposure including biomonitoring whenever as possible. Since 1996, the Lyon Poison Center has been conducting a prospective follow-up of pregnant women exposed to chemicals at the workplace. Of these, 206 exposed to organic solvents since conception were selected and matched with 206 exposed to a non-embryotoxic agent. Total withdrawal from the workplace was recommended in 22% of cases, but exposure was not considered to be hazardous to pregnancy in 51%. Overall, no increase in adverse outcomes was found. Maintaining pregnant women at their workplace, particularly most of the laboratory technicians, is reasonably possible after careful toxicological risk assessment. Copyright © 2010 Elsevier Inc. All rights reserved.

  4. Molecular Characteristics of Kraft-AQ Pulping Lignin Fractionated by Sequential Organic Solvent Extraction

    Directory of Open Access Journals (Sweden)

    Kun Wang

    2010-08-01

    Full Text Available Kraft-AQ pulping lignin was sequentially fractionated by organic solvent extractions and the molecular properties of each fraction were characterized by chemical degradation, GPC, UV, FT-IR, 13C-NMR and thermal analysis. The average molecular weight and polydispersity of each lignin fraction increased with its hydrogen-bonding capacity (Hildebrand solubility parameter. In addition, the ratio of the non-condensed guaiacyl/syringyl units and the content of β-O-4 linkages increased with the increment of the lignin fractions extracted successively with hexane, diethylether, methylene chloride, methanol, and dioxane. Furthermore, the presence of the condensation reaction products was contributed to the higher thermal stability of the larger molecules.

  5. A Solvent-Free Hot-Pressing Method for Preparing Metal-Organic-Framework Coatings.

    Science.gov (United States)

    Chen, Yifa; Li, Siqing; Pei, Xiaokun; Zhou, Junwen; Feng, Xiao; Zhang, Shenghan; Cheng, Yuanyuan; Li, Haiwei; Han, Ruodan; Wang, Bo

    2016-03-01

    Metal-organic frameworks (MOFs), with their well-defined pores and rich structural diversity and functionality, have drawn a great deal of attention from across the scientific community. However, industrial applications are hampered by their intrinsic fragility and poor processability. Stable and resilient MOF devices with tunable flexibility are highly desirable. Herein, we present a solvent- and binder-free approach for producing stable MOF coatings by a unique hot-pressing (HoP) method, in which temperature and pressure are applied simultaneously to facilitate the rapid growth of MOF nanocrystals onto desired substrates. This strategy was proven to be applicable to carboxylate-based, imidazolate-based, and mixed-metal MOFs. We further successfully obtained superhydrophobic and "Janus" MOF films through layer-by-layer pressing. This HoP method can be scaled up in the form of roll-to-roll production and may push MOFs into unexplored industrial applications.

  6. Molecular characteristics of Kraft-AQ pulping lignin fractionated by sequential organic solvent extraction.

    Science.gov (United States)

    Wang, Kun; Xu, Feng; Sun, Runcang

    2010-08-16

    Kraft-AQ pulping lignin was sequentially fractionated by organic solvent extractions and the molecular properties of each fraction were characterized by chemical degradation, GPC, UV, FT-IR, (13)C-NMR and thermal analysis. The average molecular weight and polydispersity of each lignin fraction increased with its hydrogen-bonding capacity (Hildebrand solubility parameter). In addition, the ratio of the non-condensed guaiacyl/syringyl units and the content of β-O-4 linkages increased with the increment of the lignin fractions extracted successively with hexane, diethylether, methylene chloride, methanol, and dioxane. Furthermore, the presence of the condensation reaction products was contributed to the higher thermal stability of the larger molecules.

  7. Resin-Supported Catalysts for CuAAC Click Reactions in Aqueous or Organic Solvents

    Science.gov (United States)

    Presolski, Stanislav I.; Mamidyala, Sreeman K.; Manzenrieder, Florian

    2012-01-01

    The copper-catalyzed azide-alkyne cycloaddition click reaction is a valuable process for the synthesis of libraries of drug candidates, derivatized polymers and materials, and a wide variety of other functional molecules. In some circumstances, the removal of the copper catalyst is both necessary and inconvenient. We describe here two immobilized forms of a Cu-binding ligand that has been shown to accelerate triazole formation under many different conditions, using different resin supports that are appropriate for aqueous or organic solvents. Copper leaching from these resins was modest, allowing them to be reused in many reaction/filtration cycles without recharging with metal ion. The utility of this catalyst form was demonstrated in the convenient synthesis of 20 N-acetylgalactosamine derivatives for biological testing. PMID:22946559

  8. Bioremediation of organic solvents in ground water: A case study--Grandview, Missouri

    Energy Technology Data Exchange (ETDEWEB)

    Humenik, J.A. (American Compliance Technologies, Inc., Lakeland, FL (United States))

    1993-10-01

    Organic solvents leaking from underground storage tanks or from spillage pose a serious threat to ground-water quality. Chemicals such as styrene, ethylbenzene, toluene, and methyl-methacrylate are commonly associated with the manufacturing of plastics and fiberglass. After pump-and-treat operations were unsuccessful in remediating ground water contaminated with ethylbenzene and styrene resulting from leaking underground chemical storage tanks, bioremediation was implemented to degrade the contaminants to the Missouri Department of Natural Resources target cleanup limits. Due to low permeability clays and anaerobic subsurface conditions, the bioremediation design consisted of a ground-water recovery system, an aboveground bioreactor to treat ground water, and a recharge network to introduce acclimated microbes, nutrients, and oxygen to the subsurface. Commercially prepared microbial strains and nutrients were utilized for the close-loop system, as insufficient indigenous microbes and nutrients were present in subsurface matrix.

  9. Glycerol and derived solvents: new sustainable reaction media for organic synthesis.

    Science.gov (United States)

    Díaz-Álvarez, Alba E; Francos, Javier; Lastra-Barreira, Beatriz; Crochet, Pascale; Cadierno, Victorio

    2011-06-14

    The rapid growth of the biodiesel industry has led to a large surplus of its major byproduct, i.e. glycerol, for which new applications need to be found. Research efforts in this area have focused mainly on the development of processes for converting glycerol into value-added chemicals and its reforming for hydrogen production, but recently, in line with the increasing interest in the use of alternative greener solvents, an innovative way to revalorize glycerol and some of its derivatives has seen the light, i.e. their use as environmentally friendly reaction media for synthetic organic chemistry. The aim of the present Feature Article is to provide a comprehensive overview on the developments reached in this field.

  10. Kinetic Model of Resin-Catalyzed Decomposition of Acetone Cyanohydrin in Organic Solvent

    Institute of Scientific and Technical Information of China (English)

    章亭洲; 杨立荣; 朱自强; 吴坚平

    2003-01-01

    Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with chemical catalysts and the successive operation in the bioreactor, anion exchange resin (D301) was used as catalyst for this reaction. External diffusion limitation was excluded by raising rotational speed to higher than 190r·min-1 in both solvents. Internal diffusion limitation was verified to be insignificant in this reaction system. The effect of acetone cyanohydrin concentration on the reaction was also investigated. An intrinsic kinetic model was proposed when the mass transfer limitation was excluded, and the average deviation of the model is 10.5%.

  11. Lipase-catalyzed Kinetic Resolution of Racemic 1-Trimethylsilylethanol in Organic Solvent

    Institute of Scientific and Technical Information of China (English)

    吴虹; 宗敏华; 王菊芳; 罗涤衡; 娄文勇

    2004-01-01

    The enantioselective esterification of racemic 1-trimethylsilylethanol with acids catalyzed by lipase in organic solvent was successfully performed. The influence of some factors on the reaction was investigated. Among the four lipases explored, Candlda rugosa lipase (CRL) showed the highest activity and enantioselectivity. Octanoic acid was the best acyl donor among the eleven acids studied and n-hexane was the most suitable medium for the reaction. The optimum shaking rate and temperature were found to be 150 r-rain-i and 20~(3 to 30~C, respectively.The enantiomeric excess of the remaining (S)-(-)-1-trimethylsilylethanol was 93% when substrate conversion was 53% upon incubation of the reaction mixture at 30~C, 150 r-rain-i for 12 h.

  12. Synthesis and exchange properties of sulfonated poly(phenylene sulfide) with alkali metal ions in organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Son, Won Keun [Chungnam National Univ., Taejon (Korea, Republic of); Kim, Sang Hern [Taejon National Univ., Taejon (Korea, Republic of); Park, Soo Gil [Chungbuk National Univ., Cheongju (Korea, Republic of)

    2001-01-01

    Sulfonated poly(phenylene sulfide) (SPPS) polymers were prepared by sulfonation of poly[methyl[4-(phenylthio)phenyl] sulfonium trifluoromethanesulfonate] (PPST) with fumic sulfonic acid (10% SO{sub 3}-H{sub 2}SO{sub 4}) and demethylation with aqueous NaOH solution. The equilibrium constants of ion exchange reactions between alkali metal cations (Li{sup +}, Na{sup +}, and K{sup +}) and SPPS ion exchanger in organic solvents such as in organic solvents such as tetrahydrofuran (THF) and dioxane were measured. The equilibrium constants of ion exchange reactions increased as the polarity of the solvent increased, and the reaction temperature decreased. The equilibrium constants of the ion exchange reaction (K{sub eq}) also increased in the order of Li{sup +}, Na{sup +}, and K{sup +}. To elucidate the spontaneity of the exchange reaction in organic solvents, the enthalpy, entropy, and Gibbs free energy were calculated. The enthalpy of reaction ranged from -0.88 to -1.33 kcal/mol, entropy ranged from 1.42 to 4.41 cal/Kmol, and Gibbs free energy ranged from -1.03 to -2.55 kcal/mol. Therefore, the exchange reactions were spontaneous because the Gibbs free energies were negative. The SPPS ion exchanger and alkali metal ion bounding each other produced good ion exchange capability in organic solvents.

  13. Solvent effects of a dimethyldicyanoquinonediimine buffer layer as N-type material on the performance of organic photovoltaic cells.

    Science.gov (United States)

    Yang, Eui Yeol; Oh, Se Young

    2014-08-01

    In the present work, we have fabricated organic photovoltaic cells consisting of ITO/PEDOT:PSS/P3HT:PCBM/DMDCNQI/Al using a dip-coating method with various solvent systems. We have investigated solvent effects (such as solubility, viscosity and vapor pressure) in deposition of a thin DMDCNQI buffer layer on the performance of organic photovoltaic cells. The solvent system which had low viscosity and good solubility properties, made a dense and uniform DMDCNQI ultra thin film, resulting in a high performance device. In particular, a prepared organic photovoltaic cell was fabricated using a cosolvent system (methanol:methylenechloride = 3:1) and showed a maximum power conversion efficiency of 4.53%.

  14. Noise-induced hearing loss in Korean workers: co-exposure to organic solvents and heavy metals in nationwide industries.

    Directory of Open Access Journals (Sweden)

    Yoon-Hyeong Choi

    Full Text Available BACKGROUND: Noise exposure is a well-known contributor to work-related hearing loss. Recent biological evidence suggests that exposure to ototoxic chemicals such as organic solvents and heavy metals may be additional contributors to hearing loss. However, in industrial settings, it is difficult to determine the risks of hearing loss due to these chemicals in workplaces accompanied by excessive noise exposure. A few studies suggest that the effect of noise may be enhanced by ototoxic chemicals. Therefore, this study investigated whether co-exposure to organic solvents and/or heavy metals in the workplace modifies the risk of noise exposure on hearing loss in a background of excessive noise. METHODS: We examined 30,072 workers nationwide in a wide range of industries from the Korea National Occupational Health Surveillance 2009. Data on industry-based exposure (e.g., occupational noise, heavy metals, and organic solvents and subject-specific health outcomes (e.g., audiometric examination were collected. Noise was measured as the daily 8-h time-weighted average level. Air conduction hearing thresholds were measured from 0.5 to 6 kHz, and pure-tone averages (PTA (i.e., means of 2, 3, and 4 kHz were computed. RESULTS: In the multivariate linear model, PTA increment with occupational noise were 1.64-fold and 2.15-fold higher in individuals exposed to heavy metals and organic solvents than in unexposed individuals, respectively. CONCLUSION: This study provides nationwide evidence that co-exposure to heavy metals and/or organic solvents may exacerbate the effect of noise exposure on hearing loss in workplaces. These findings suggest that workers in industries dealing with heavy metals or organic solvents are susceptible to such risks.

  15. Solvents induced ZnO nanoparticles aggregation associated with their interfacial effect on organic solar cells.

    Science.gov (United States)

    Li, Pandeng; Jiu, Tonggang; Tang, Gang; Wang, Guojie; Li, Jun; Li, Xiaofang; Fang, Junfeng

    2014-10-22

    ZnO nanofilm as a cathode buffer layer has surface defects due to the aggregations of ZnO nanoparticles, leading to poor device performance of organic solar cells. In this paper, we report the ZnO nanoparticles aggregations in solution can be controlled by adjusting the solvents ratios (chloroform vs methanol). These aggregations could influence the morphology of ZnO film. Therefore, compact and homogeneous ZnO film can be obtained to help achieve a preferable power conversion efficiency of 8.54% in inverted organic solar cells. This improvement is attributed to the decreased leakage current and the increased electron-collecting efficiency as well as the improved interface contact with the active layer. In addition, we find the enhanced maximum exciton generation rate and exciton dissociation probability lead to the improvement of device performance due to the preferable ZnO dispersion. Compared to other methods of ZnO nanofilm fabrication, it is the more convenient, moderate, and effective to get a preferable ZnO buffer layer for high-efficiency organic solar cells.

  16. Analysis of metabolic pathways by the growth of cells in the presence of organic solvents.

    Science.gov (United States)

    Spinnler, H E; Ginies, C; Khan, J A; Vulfson, E N

    1996-01-01

    A new approach to the analysis of metabolic pathways involving poorly water-soluble intermediates is proposed. It relies upon the ability of the hydrophobic intermediates formed by a sequence of intracellular reactions to cross the membrane(s) and partition between aqueous and organic phases, when cells are incubated in the presence of a nonpolar and nontoxic organic solvent. As a result of this thermodynamically driven efflux of the formed intermediates from the cell, they accumulate in the organic medium in sufficient quantities for GC-MS analysis and identification. This enables direct determination of the sequence of chemical reactions involved with no requirement for the isolation of each individual metabolite from a cell-free extract. The feasibility of the proposed methodology has been demonstrated by the elucidation of the biosynthesis of (R)-gamma-decalactone from (R)-ricinoleic acid catalyzed by the yeast Sporidiobolus ruinenii grown in the presence of decane. The corresponding 4-hydroxy-acid intermediates, formed in the course of beta-oxidation of (R)-ricinoleic acid, were simultaneously observed in a single experiment on the same chromatogram. Potential applications of this proposed methodology are briefly discussed. Images Fig. 1 PMID:11607651

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Gisela L. Schulz

    2013-10-01

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

  19. Aqueous or solvent based surface modification: The influence of the combination solvent - organic functional group on the surface characteristics of titanium dioxide grafted with organophosphonic acids

    Science.gov (United States)

    Roevens, Annelore; Van Dijck, Jeroen G.; Geldof, Davy; Blockhuys, Frank; Prelot, Benedicte; Zajac, Jerzy; Meynen, Vera

    2017-09-01

    To alter the versatility of interactions at its surface, TiO2 is modified with organophosphonic acids (PA). A thorough understanding of the role of all synthesis conditions is necessary to achieve controlled functionalization. This study reports on the effect of using water, toluene and their mixtures when performing the modification of TiO2 with PA. Sorption and calorimetry measurements of surface interactions with various probing species clearly indicate that, by grafting PA in water, clear differences appear in the distribution of organic groups on the surface. Also the functional group of the PA determines the impact of using water as solvent. Modification in toluene results in a higher modification degree for propylphosphonic acid (3PA), as the solvent-solute interaction may hinder the grafting with phenylphosphonic acid (PhPA) in toluene. Water is preferred as solvent for PhPA modification as stabilizing π-OH interactions enhance surface grafting overcoming the competitive interaction of water at the surface as observed with 3PA. By using water in toluene mixtures for the functionalization of TiO2 with 3PA, the degree of functionalization is higher than when only water or toluene is used. Furthermore, adding small amounts of water leads to the formation of titanium propylphosphonates, next to surface grafting.

  20. System Development from Organic Solvents to Ionic Liquids for Synthesiz-ing Ascorbyl Esters with Conjugated Linoleic Acids

    DEFF Research Database (Denmark)

    Yang, Zhiyong; Schultz, Lise; Guo, Zheng;

    2012-01-01

    The aim of this paper is to screen suitable reaction systems for the modification of antioxidants through enzy-matic synthesis. Enzymatic esterification of ascorbic acid with conjugated linoleic acid (CLA) was investigated as a mod-el. Four organic solvents and five different enzymes were evaluated....... Results show that only Novozym® 435 turned out to be a useful enzymatic preparation for the production of ascorbyl-CLA ester. The optimum reaction conditions in the or-ganic solvent system were 4 h at 55°C and at a molar ratio of 5 (CLA/ascorbic acid). The esterification reaction was trans...

  1. SOLVENT EFFECTS ON THE HYDRATION OF CYCLOHEXENE CATALYZED BY A STRONG ACID ION-EXCHANGE RESIN .1. SOLUBILITY OF CYCLOHEXENE IN AQUEOUS SULFOLANE MIXTURES

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    1992-01-01

    The solubility of cyclohexene in different water-sulfolane mixtures was measured between 313 and 413 K. The results demonstrate a sharp increase of the solubility of cyclohexene with increasing percentages of sulfolane in the solvent mixture. Without sulfolane the increase of the solubility with tem

  2. Reverse micelles in organic solvents: a medium for the biotechnological use of extreme halophilic enzymes at low salt concentration

    Directory of Open Access Journals (Sweden)

    Frutos C. Marhuenda-Egea

    2002-01-01

    Full Text Available Alkaline p-nitrophenylphosphate phosphatase (pNPPase from the halophilic archaeobacterium Halobacterium salinarum (previously halobium was solubilized at low salt concentration in reverse micelles of hexadecyltrimethylammoniumbromide in cyclohexane with 1-butanol as cosurfactant. The enzyme maintained its catalytic properties under these conditions. The thermodynamic “solvation–stabilization hypothesis” has been used to explain the bell-shaped dependence of pNPPase activity on the water content of reverse micelles, in terms of protein–solvent interactions. According to this model, the stability of the folded protein depends on a network of hydrated ions associated with acidic residues at the protein surface. At low salt concentration and low water content (the ratio of water concentration to surfactant concentration; w0, the network of hydrated ions within the reverse micelles may involve the cationic heads of the surfactant. The bell-shaped profile of the relationship between enzyme activity and w0 varied depending on the concentrations of NaCl and Mn2+.

  3. Environment friendly chemoselective deprotection of acetonides and cleavage of acetals and ketals in aqueous medium without using any catalyst or organic solvent

    Indian Academy of Sciences (India)

    S Mukherjee; A Sengupta; S C Roy

    2013-11-01

    Highly chemoselective environment friendly deprotection of acetonides and cleavage of acetals and ketones has been achieved by heating in aqueous medium without using any catalyst and organic solvent.

  4. Esterification degree of fructose laurate exerted by Candida antarctica lipase B in organic solvents.

    Science.gov (United States)

    Li, Lu; Ji, Fangling; Wang, Jingyun; Li, Yachen; Bao, Yongming

    2015-02-01

    Sugar esters of fatty acids have many applications as biocompatible and biodegradable emulsifiers, which are determined by their degrees of esterification (DE). Direct esterification of fructose with lauric acid in organic media used commercial immobilized Candida antarctica lipase B (CALB) was investigated for DE. Significant difference of DE was observed between 2-methyl-2-butanol (2M2B) and methyl ethyl ketone (MEK), as di-ester/mono-ester molar ratio of 1.05:1 in 2M2B and 2.79:1 in MEK. Fourier transform infrared (FTIR) spectra showed that the secondary structure of the enzyme binding mono-ester presented distinct difference in 2M2B and MEK. Contents of β-turn and antiparallel β-sheet of CALB in 2M2B were 26.9% and 16.2%, respectively, but 19.1% and 13.2% in MEK. To understand the relationship between the conformational changes and differences of DE, mono-ester and fatty acid were directly employed for synthesis of di-ester. The maximum initial velocity of di-ester synthesis in MEK was 0.59 mmolg(enzyme)(-1)h(-1), which was 2.19-fold as greater as that in 2M2B, indicating that CALB conformation in MEK was preferred for the synthesis of di-ester. These results demonstrated that the conformation of CALB binding mono-ester affected by organic solvents essentially determined DE.

  5. Investigations on diffusion limitations of biocatalyzed reactions in amphiphilic polymer conetworks in organic solvents.

    Science.gov (United States)

    Schoenfeld, Ina; Dech, Stephan; Ryabenky, Benjamin; Daniel, Bastian; Glowacki, Britta; Ladisch, Reinhild; Tiller, Joerg C

    2013-09-01

    The use of enzymes as biocatalysts in organic media is an important issue in modern white biotechnology. However, their low activity and stability in those media often limits their full-scale application. Amphiphilic polymer conetworks (APCNs) have been shown to greatly activate entrapped enzymes in organic solvents. Since these nanostructured materials are not porous, the bioactivity of the conetworks is strongly limited by diffusion of substrate and product. The present manuscript describes two different APCNs as nanostructured microparticles, which showed greatly increased activities of entrapped enzymes compared to those of the already activating membranes and larger particles. We demonstrated this on the example of APCN particles based on PHEA-l-PDMS loaded with α-Chymotrypsin, which resulted in an up to 28,000-fold higher activity of the enzyme compared to the enzyme powder. Furthermore, lipase from Rhizomucor miehei entrapped in particles based on PHEA-l-PEtOx was tested in n-heptane, chloroform, and substrate. Specific activities in smaller particles were 10- to 100-fold higher in comparison to the native enzyme. The carrier activity of PHEA-l-PEtOx microparticles was tenfold higher with some 25-50-fold lower enzyme content compared to a commercial product.

  6. Cold-adapted organic solvent tolerant alkalophilic family I.3 lipase from an Antarctic Pseudomonas.

    Science.gov (United States)

    Ganasen, Menega; Yaacob, Norhayati; Rahman, Raja Noor Zaliha Raja Abd; Leow, Adam Thean Chor; Basri, Mahiran; Salleh, Abu Bakar; Ali, Mohd Shukuri Mohamad

    2016-11-01

    Lipolytic enzymes with cold adaptation are gaining increasing interest due to their biotechnological prospective. Previously, a cold adapted family I.3 lipase (AMS8 lipase) was isolated from an Antarctic Pseudomonas. AMS8 lipase was largely expressed in insoluble form. The refolded His-tagged recombinant AMS8 lipase was purified with 23.0% total recovery and purification factor of 9.7. The purified AMS8 lipase migrated as a single band with a molecular weight approximately 65kDa via electrophoresis. AMS8 lipase was highly active at 30°C at pH 10. The half-life of AMS8 lipase was reported at 4 and 2h under the incubation of 30 and 40°C, respectively. The lipase was stable over a broad range of pH. It showed enhancement effect in its relative activity under the presence of Li(+), Na(+), K(+), Rb(+) and Cs(+) after 30min treatment. Heavy metal ions such as Cu(2+), Fe(3+) and Zn(2+) inhibited AMS8 activity. This cold adapted alkalophilic AMS lipase was also active in various organic solvent of different polarity. These unique properties of this biological macromolecule will provide considerable potential for many biotechnological applications and organic synthesis at low temperature.

  7. 40 CFR Table 5 to Subpart Qqqq of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Science.gov (United States)

    2010-07-01

    ... Wood Building Products Pt. 63, Subpt. QQQQ, Table 5 Table 5 to Subpart QQQQ of Part 63—Default Organic... mineral spirits 8032-32-4 0 None. 12. Ligroines (VM & P) 8032-32-4 0 None. 13. Lactol spirits 64742-89-6 0.15 Toluene. 14. Low aromatic white spirit 64742-82-1 0 None. 15. Mineral spirits 64742-88-7...

  8. Scalable synthesis of organic-soluble carbon quantum dots: superior optical properties in solvents, solids, and LEDs.

    Science.gov (United States)

    Wu, Minghong; Zhan, Jing; Geng, Bijiang; He, Piaopiao; Wu, Kuan; Wang, Liang; Xu, Gang; Li, Zhen; Yin, Luqiao; Pan, Dengyu

    2017-09-14

    Carbon quantum dots (CQDs) have attracted much attention owing to their unique optical properties and a wide range of applications. The fabrication and control of CQDs with organic solubility and long-wavelength emission are still urgent issues to be addressed for their practical use in LEDs. Here, organic-soluble CQDs were produced at a high yield of ∼90% by a facile solvent engineering treatment of 1,3,6-trinitropyrene, which were simultaneously used as the nitrogen and carbon sources. The optical properties of the organic-soluble CQDs (o-CQDs) were investigated in nonpolar and polar solvents, films, and LED devices. The CQDs have a narrow size distribution around 2.66 nm, and can be dispersed in different organic solvents. Significantly, the as-prepared CQDs present an excitation-independent emission at 607 nm with fluorescence quantum yields (QYs) up to 65.93% in toluene solution. A pronounced solvent effect was observed and their strong absorption bands can be tuned in the whole visible region (400-750 nm) by changing the solvent. The CQDs in various solvents can emit bright, excitation-independent, long-wavelength fluorescence (orange to red). Furthermore, benefiting from the unique oil-solution properties, the as-prepared CQDs can be processed in thin film and device forms to meet the requirements of various applications, such as phosphor-based white-light LEDs. The color coordinate for these CQD modified LEDs is realized at (0.32, 0.31), which is close to pure white light (0.33, 0.33).

  9. Highly efficient synthesis of endomorphin-2 under thermodynamic control catalyzed by organic solvent stable proteases with in situ product removal.

    Science.gov (United States)

    Xu, Jiaxing; Sun, Honglin; He, Xuejun; Bai, Zhongzhong; He, Bingfang

    2013-02-01

    An efficient enzymatic synthesis of endomorphin-2 (EM-2) was achieved using organic solvent stable proteases in nonaqeous media, based on thermodynamic control and an in situ product removal methodology. The high stability of biocatalysts in organic solvents enabled the aleatoric modulation of the nonaqueous reaction media to shift thermodynamic equilibrium toward synthesis. Peptide Boc-Phe-Phe-NH2 was synthesized with a high yield of 96% by the solvent stable protease WQ9-2 in monophase medium with an economical molar ratio of the substrate of 1:1. The tetrapeptide Boc-Tyr-Pro-Phe-Phe-NH2 was synthesized with a yield of 88% by another organic solvent tolerant protease PT121 from Boc-Tyr-Pro-OH and Phe-Phe-NH2 in an organic-aqueous biphasic system. The reaction-separation coupling in both enzymatic processes provides "driving forces" for the synthetic reactions and gives a high yield and high productivity without purification of the intermediate, thereby making the synthesis more amenable to scale-up. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Organic solvents vapor pressure and relative humidity effects on the phase transition rate of α and β forms of tegafur.

    Science.gov (United States)

    Petkune, Sanita; Bobrovs, Raitis; Actiņš, Andris

    2012-01-01

    The objective of this work was to investigate the relative humidity (RH) and solvent vapor pressure effects on the phase transition dynamics between tegafur polymorphic forms that do not form hydrates and solvates. The commercially available α and β modifications of 5-fluoro-1-(tetrahydro-2-furyl)-uracil, known as the antitumor agent tegafur, were used as model materials for this study. While investigating the phase transitions of α and β tegafur under various partial pressures of methanol, n-propanol, n-butanol, and water vapor, it was determined that the phase transition rate increased in the presence of solvent vapors, even though no solvates were formed. By increasing the relative air humidity from 20% to 80%, the phase transition rate constant of α and β tegafur was increased about 60 times. After increasing the partial pressure of methanol, n-propanol, or n-butanol vapor, the phase transition rate constant did not change, but the extent of phase transformation was increased. In the homologous row of n-alcohols, the phase transition rate constant decreased with increasing carbon chain length. The dependence of phase transformation extent versus the RH corresponded to the polymolecular adsorption isotherm with a possible capillary condensation effect.

  11. Mechanistic Aspects in the Formation, Growth and Surface Functionalization of Metal Oxide Nanoparticles in Organic Solvents.

    Science.gov (United States)

    Niederberger, Markus; Deshmukh, Rupali

    2017-04-04

    The synthesis of metal oxide nanoparticles in organic solvents, so-called nonaqueous (or nonhydrolytic) processes represent powerful alternatives to aqueous approaches and have become an independent research field. 10 years ago, when we published our first review on organic reaction pathways in nonaqueous sol-gel approaches,[1] the number of examples was relatively limited. Nowadays, it is almost impossible to provide an exhaustive overview. Here we review the development of the last few years, without neglecting pioneering examples, which help to follow the historical development. The importance of a profound understanding of mechanistic aspects of nanoparticle crystallization and formation mechanisms can't be overestimated, when it comes to the design of rational synthesis concepts under minimization of trial-and-error experiments. The main reason for the progress in mechanistic understanding lies in the availability of characterization tools that make it possible to monitor chemical reactions from the dissolution of the precursor to the nucleation and growth of the nanoparticles, by ex-situ methods involving sampling after different reaction times, but more and more also by in-situ studies. After a short introduction to experimental aspects of nonaqueous sol-gel routes to metal oxide nanoparticles, we provide an overview of the main and basic organic reaction pathways in these approaches. Afterwards, we summarize the main characterization methods to study formation mechanisms, and then we discuss in great depth the chemical formation mechanisms of many different types of metal oxide nanoparticles. The review concludes with a paragraph on selected crystallization mechanisms reported for nonaqueous systems and a few illustrative examples of nonaqueous sol-gel concepts applied to surface chemistry.

  12. Organic solvent wetting properties of UV and plasma treated ZnO nanorods: printed electronics approach

    KAUST Repository

    Sliz, Rafal

    2012-09-13

    Due to low manufacturing costs, printed organic solar cells are on the short-list of renewable and environmentally- friendly energy production technologies of the future. However, electrode materials and each photoactive layer require different techniques and approaches. Printing technologies have attracted considerable attention for organic electronics due to their potentially high volume and low cost processing. A case in point is the interface between the substrate and solution (ink) drop, which is a particularly critical issue for printing quality. In addition, methods such as UV, oxygen and argon plasma treatments have proven suitable to increasing the hydrophilicity of treated surfaces. Among several methods of measuring the ink-substrate interface, the simplest and most reliable is the contact angle method. In terms of nanoscale device applications, zinc oxide (ZnO) has gained popularity, owing to its physical and chemical properties. In particular, there is a growing interest in exploiting the unique properties that the so-called nanorod structure exhibits for future 1-dimensional opto-electronic devices. Applications, such as photodiodes, thin-film transistors, sensors and photo anodes in photovoltaic cells have already been demonstrated. This paper presents the wettability properties of ZnO nanorods treated with UV illumination, oxygen and argon plasma for various periods of time. Since this work concentrates on solar cell applications, four of the most common solutions used in organic solar cell manufacture were tested: P3HT:PCBM DCB, P3HT:PCBM CHB, PEDOT:PSS and water. The achieved results prove that different treatments change the contact angle differently. Moreover, solvent behaviour varied uniquely with the applied treatment. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  13. Organic solvent wetting properties of UV and plasma treated ZnO nanorods: printed electronics approach

    Science.gov (United States)

    Sliz, Rafal; Suzuki, Yuji; Nathan, Arokia; Myllyla, Risto; Jabbour, Ghassan

    2012-09-01

    Due to low manufacturing costs, printed organic solar cells are on the short-list of renewable and environmentally- friendly energy production technologies of the future. However, electrode materials and each photoactive layer require different techniques and approaches. Printing technologies have attracted considerable attention for organic electronics due to their potentially high volume and low cost processing. A case in point is the interface between the substrate and solution (ink) drop, which is a particularly critical issue for printing quality. In addition, methods such as UV, oxygen and argon plasma treatments have proven suitable to increasing the hydrophilicity of treated surfaces. Among several methods of measuring the ink-substrate interface, the simplest and most reliable is the contact angle method. In terms of nanoscale device applications, zinc oxide (ZnO) has gained popularity, owing to its physical and chemical properties. In particular, there is a growing interest in exploiting the unique properties that the so-called nanorod structure exhibits for future 1-dimensional opto-electronic devices. Applications, such as photodiodes, thin-film transistors, sensors and photo anodes in photovoltaic cells have already been demonstrated. This paper presents the wettability properties of ZnO nanorods treated with UV illumination, oxygen and argon plasma for various periods of time. Since this work concentrates on solar cell applications, four of the most common solutions used in organic solar cell manufacture were tested: P3HT:PCBM DCB, P3HT:PCBM CHB, PEDOT:PSS and water. The achieved results prove that different treatments change the contact angle differently. Moreover, solvent behaviour varied uniquely with the applied treatment.

  14. Nickel-Catalyzed Suzuki–Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory

    Science.gov (United States)

    2015-01-01

    A modern undergraduate organic chemistry laboratory experiment involving the Suzuki–Miyaura coupling is reported. Although Suzuki–Miyaura couplings typically employ palladium catalysts in environmentally harmful solvents, this experiment features the use of inexpensive nickel catalysis, in addition to a “green” alcohol solvent. The experiment employs heterocyclic substrates, which are important pharmaceutical building blocks. Thus, this laboratory procedure exposes students to a variety of contemporary topics in organic chemistry, including transition metal-catalyzed cross-couplings, green chemistry, and the importance of heterocycles in drug discovery, none of which are well represented in typical undergraduate organic chemistry curricula. The experimental protocol uses commercially available reagents and is useful in both organic and inorganic instructional laboratories. PMID:25774064

  15. Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

    Directory of Open Access Journals (Sweden)

    Célia A. Alves

    2008-03-01

    Full Text Available In spite of accounting for 10-70% of the atmospheric aerosol mass, particulate-phase organic compounds are not well characterised, and many aspects of aerosol formation and evolution are still unknown. The growing awareness of the impact of particulate aerosols on climate, and the incompletely recognised but serious effects of anthropogenic constituents on air quality and human health, have conducted to several scientific studies. These investigations have provided information about the behaviour of atmospheric particulate matter and the description of the character of its carbonaceous content. The compilation of such results is important as they append to the emergent global-wide dataset of the organic composition of atmospheric aerosols. The contribution of the major emission sources to regional particulate pollution can be diagnosed by using specific molecular markers. This overview is mainly focused on results obtained with gas chromatography coupled with mass spectrometry, since it is the analytical method of choice in elucidating the solvent-extractable organic compounds in atmospheric particulate matter. A synopsis of the selection of organic tracers and the application of geochemical parameters to the analysis of organic constituents as a tool for source apportionment is shown here. Besides the assessment of current knowledge, this paper also presents the identification of further areas of concern.Apesar de constituirem 10-70% da massa do aerosol atmosférico, a caracterização dos compostos orgânicos particulados permanece ainda deficitária e vários aspectos relativos à formação e evolução do aerossol são ainda desconhecidos. A crescente preocupação com o impacto do aerosol particulado no clima e os reconhecidos efeitos dos constituintes antropogênicos na qualidade do ar e na saúde humana têm motivado a realização de numerosos estudos. Estas investigações têm fornecido informações relevantes sobre o comportamento

  16. Investigation of the Regioselectivity of Alkene Hydrations for the Undergraduate Organic Laboratory

    Science.gov (United States)

    Bichler, Katherine A.; Van Ornum, Scott G.; Franz, Margaret C.; Imhoff, Andrea M.

    2015-01-01

    Due to a lack of time and, thus, an inability to present every possibility in a chemical reaction, organic chemistry professors tend to present each reaction with a single outcome. In practice, this is clearly not the case. A first-semester, three-week laboratory experiment designed for undergraduate organic chemistry students is described in…

  17. Effect of Solvent-Assisted Nanoscaled Organo-Gels on Morphology and Performance of Organic Solar Cells

    DEFF Research Database (Denmark)

    Zuo, Li-Jian; Hu, Xiao-Lian; Ye, Tao

    2012-01-01

    .e., organo-gels) behavior as a function of steric hindrance of aromatic solvents imposed by substituents. We showed that the size of organo-gels decreased as the substituents of solvents got larger. Also, the phase separation and domain size of the subsequent spin-coated films increased monotonically...... with that of the organo-gels in solution. Through this knowledge, we eventually achieve controlled morphology and optimized organic solar cells (OSCs) performance. Our results present a significant step forward for understanding the self-assembly behavior of conjugated polymers, control of their morphology...... and optimization of OSC performance....

  18. Separation of reaction product and palladium catalyst after a Heck coupling reaction by means of organic solvent nanofiltration.

    Science.gov (United States)

    Tsoukala, Anna; Peeva, Ludmila; Livingston, Andrew G; Bjørsvik, Hans-René

    2012-01-09

    Organic solvent nanofiltration (OSN) is a recently commercialized technology, which we have used to develop a method for the separation of a target product and the Pd catalyst from a Heck coupling postreaction mixture. The experimental setup included commercially available polyimide copolymer membranes with molecular weight cut-off (MWCO) values in the range of 150-300 Da, acetone as the solvent, and a working pressure (N(2)) of 3 MPa. The investigation of the membranes revealed that a membrane with a MWCO of 200 Da provided quantitative retention of the Pd catalyst and quantitative recovery of the target product by means of a cross-flow dia-nanofiltration procedure.

  19. 40 CFR Table 6 to Subpart Vvvv of... - Default Organic HAP Contents of Petroleum Solvent Groups

    Science.gov (United States)

    2010-07-01

    ... Spirits 150 EC, Naphtha, Mixed Hydrocarbon, Aliphatic Hydrocarbon, Aliphatic Naptha, Naphthol Spirits, Petroleum Spirits, Petroleum Oil, Petroleum Naphtha, Solvent Naphtha, Solvent Blend.) 3 1% Xylene, 1% Toluene, and 1% Ethylbenzene. Aromatic (Medium-flash Naphtha, High-flash Naphtha, Aromatic Naphtha, Light...

  20. Use of volatile organic solvents in headspace liquid-phase microextraction by direct cooling of the organic drop using a simple cooling capsule.

    Science.gov (United States)

    Ghiasvand, Ali Reza; Yazdankhah, Fatemeh; Hajipour, Somayeh

    2016-08-01

    A low-cost and simple cooling-assisted headspace liquid-phase microextraction device for the extraction and determination of 2,6,6-trimethyl-1,3 cyclohexadiene-1-carboxaldehyde (safranal) in Saffron samples, using volatile organic solvents, was fabricated and evaluated. The main part of the cooling-assisted headspace liquid-phase microextraction system was a cooling capsule, with a Teflon microcup to hold the extracting organic solvent, which is able to directly cool down the extraction phase while the sample matrix is simultaneously heated. Different experimental factors such as type of organic extraction solvent, sample temperature, extraction solvent temperature, and extraction time were optimized. The optimal conditions were obtained as: extraction solvent, methanol (10 μL); extraction temperature, 60°C; extraction solvent temperature, 0°C; and extraction time, 20 min. Good linearity of the calibration curve (R(2) = 0.995) was obtained in the concentration range of 0.01-50.0 μg/mL. The limit of detection was 0.001 μg/mL. The relative standard deviation for 1.0 μg/mL of safranal was 10.7% (n = 6). The proposed cooling-assisted headspace liquid-phase microextraction device was coupled (off-line) to high-performance liquid chromatography and used for the determination of safranal in Saffron samples. Reasonable agreement was observed between the results of the cooling-assisted headspace liquid-phase microextraction high-performance liquid chromatography method and those obtained by a validated ultrasound-assisted solvent extraction procedure.

  1. Rapid recovery of polycrystalline silicon from kerf loss slurry using double-layer organic solvent sedimentation method

    Science.gov (United States)

    Xing, Peng-fei; Guo, Jing; Zhuang, Yan-xin; Li, Feng; Tu, Gan-feng

    2013-10-01

    The rapid development of photovoltaic (PV) industries has led to a shortage of silicon feedstock. However, more than 40% silicon goes into slurry wastes due to the kerf loss in the wafer slicing process. To effectively recycle polycrystalline silicon from the kerf loss slurry, an innovative double-layer organic solvent sedimentation process was presented in the paper. The sedimentation velocities of Si and SiC particles in some organic solvents were investigated. Considering the polarity, viscosity, and density of solvents, the chloroepoxy propane and carbon tetrachloride were selected to separate Si and SiC particles. It is found that Si and SiC particles in the slurry waste can be successfully separated by the double-layer organic solvent sedimentation method, which can greatly reduce the sedimentation time and improve the purity of obtained Si-rich and SiC-rich powders. The obtained Si-rich powders consist of 95.04% Si, and the cast Si ingot has 99.06% Si.

  2. Source profiles of volatile organic compounds associated with solvent use in Beijing, China

    Science.gov (United States)

    Yuan, Bin; Shao, Min; Lu, Sihua; Wang, Bin

    2010-05-01

    Compositions of volatile organic compound (VOC) emissions from painting applications and printing processes were sampled and measured by gas chromatography-mass spectrometry/flame ionization detection (GC-MS/FID) in Beijing. Toluene and C8 aromatics were the most abundant species, accounting for 76% of the total VOCs emitted from paint applications. The major species in printing emissions included heavier alkanes and aromatics, such as n-nonane, n-decane, n-undecane, toluene, and m/p-xylene. Measurements of VOCs obtained from furniture paint emissions in 2003 and 2007 suggest a quick decline in benzene levels associated with formulation changes in furniture paints during these years. A comparison of VOC source profiles for painting and printing between Beijing and other parts of the world showed significant region-specific discrepancies, probably because of different market demands and environmental standards. We conducted the evaluation of the source reactivities for various VOC emission sources. The ozone formation potential (OFP) for unit mass of VOCs source emissions is the highest for paint applications. Substituting solvent-based paints by water-based in Beijing will lead to an OFP reduction of 152,000 tons per year, which is more than 1/4 of the OFPs for VOCs emissions from vehicle exhaust in the city.

  3. Sweeping of alprenolol enantiomers with an organic solvent and sulfated β-cyclodextrin in capillary electrophoresis.

    Science.gov (United States)

    Rabanes, Heide R; Quirino, Joselito P

    2013-05-01

    Sweeping, an on-line sample concentration technique in CE, is the picking and accumulation of analytes by the pseudostationary phase or complexing additive. In the presence of an electric field, the analytes concentrated at the additive front that initially penetrated the sample zone. Here, we describe the sweeping of cationic alprenolol enantiomers using sulfated β-CD and organic solvent. The separation solution contained the anionic additive while ACN was in the sample solution. With fused silica capillaries, positive polarity, and solutions buffered at pH 3, the direction of the enantiomers' effective electrophoretic mobility was the same as the electrophoretic mobility (or electrophoretic mobility without additive). When the amount of ACN in the sample was increased (i.e. 60%), the interaction between the analytes and additive became negligible. This caused the sweeping boundary to shift from the electrophoretically moving β-CD front to the zone between the sample and separation solution. The equation that described the narrowing of injected sample zone was derived. The performance of sweeping with 60% ACN in the sample was then studied under different operating conditions (e.g. type of injection, injection time, and CD concentration). The low interaction between enantiomers and additive gave only moderate increases in sensitivity (approximately tenfold), but was improved when field enhancement was used during electrokinetic injection. With a conductivity difference (separation/sample solution) of 70 and a short injection time of 30 s at 20 kV, peak improvements of >100-fold was easily achieved.

  4. In-Vitro Characterization and Oral Bioavailability of Organic Solvent-free Solid Dispersions Containing Telmisartan

    Science.gov (United States)

    Cao, Yue; Shi, Li-Li; Cao, Qing-Ri; Yang, Mingshi; Cui, Jing-Hao

    2016-01-01

    Poorly water-soluble drugs often suffer from limited or irreproducible clinical response due to their low solubility and dissolution rate. In this study, organic solvent-free solid dispersions (OSF-SDs) containing telmisartan (TEL) were prepared using polyvinylpyrrolidone K30 (PVP K30) and polyethylene glycol 6000 (PEG 6000) as hydrophilic polymers, sodium hydroxide (NaOH) as an alkalizer, and poloxamer 188 as a surfactant by a lyophilization method. In-vitro dissolution rate and physicochemical properties of the OSF-SDs were characterized using the USP I basket method, differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and fourier transform-infrared (FT-IR) spectroscopy. In addition, the oral bioavailability of OSF-SDs in rats was evaluated by using TEL bulk powder as a reference. The dissolution rates of the OSF-SDs were significantly enhanced as compared to TEL bulk powder. The results from DSC, XRD showed that TEL was molecularly dispersed in the OSF-SDs as an amorphous form. The FT-IR results suggested that intermolecular hydrogen bonding had formed between TEL and its carriers. The OSF-SDs exhibited significantly higher AUC0–24 h and Cmax, but similar Tmax as compared to the reference. This study demonstrated that OSF-SDs can be a promising method to enhance the dissolution rate and oral bioavailability of TEL. PMID:27642309

  5. Electrochemistry of Simple Organometallic Models of Iron-Iron Hydrogenases in Organic Solvent and Water.

    Science.gov (United States)

    Gloaguen, Frederic

    2016-01-19

    Synthetic models of the active site of iron-iron hydrogenases are currently the subjects of numerous studies aimed at developing H2-production catalysts based on cheap and abundant materials. In this context, the present report offers an electrochemist's view of the catalysis of proton reduction by simple binuclear iron(I) thiolate complexes. Although these complexes probably do not follow a biocatalytic pathway, we analyze and discuss the interplay between the reduction potential and basicity and how these antagonist properties impact the mechanisms of proton-coupled electron transfer to the metal centers. This question is central to any consideration of the activity at the molecular level of hydrogenases and related enzymes. In a second part, special attention is paid to iron thiolate complexes holding rigid and unsaturated bridging ligands. The complexes that enjoy mild reduction potentials and stabilized reduced forms are promising iron-based catalysts for the photodriven evolution of H2 in organic solvents and, more importantly, in water.

  6. Microwave activation of electrochemical processes: enhanced electrodehalogenation in organic solvent media.

    Science.gov (United States)

    Tsai, Yu-Chen; Coles, Barry A; Compton, Richard G; Marken, Frank

    2002-08-21

    The effect of high-intensity microwave radiation focused into a "hot spot" region in the vicinity of an electrode on electrochemical processes with and without coupled chemical reaction steps has been investigated in organic solvent media. First, the electrochemically reversible oxidation of ferrocene in acetonitrile and DMF is shown to be affected by microwave-induced thermal activation, resulting in increased currents and voltammetric wave shape effects. A FIDAP simulation investigation allows quantitative insight into the temperature distribution and concentration gradients at the electrode / solution interface. Next, the effect of intense microwave radiation on electroorganic reactions is considered for the case of ECE processes. Experimental data for the reduction of p-bromonitrobenzene, o-bromonitrobenzene, and m-iodonitrobenzene in DMF and acetonitrile are analyzed in terms of an electron transfer (E), followed by a chemical dehalogenation step (C), and finally followed by another electron-transfer step (E). The presence of the "hot spot" in the solution phase favors processes with high activation barriers.

  7. Monitoring of the aerobe biodegradation of chlorinated organic solvents by stable isotope analysis

    Science.gov (United States)

    Horváth, Anikó; Futó, István; Palcsu, László

    2014-05-01

    Our chemical-biological basic research aims to eliminate chlorinated environmental contaminants from aquifers around industrial areas in the frame of research program supported by the European Social Fund (TÁMOP-4.2.2.A-11/1/KONV-2012-0043). The most careful and simplest way includes the in situ biodegradation with the help of cultured and compound specific strains. Numerous members of Pseudomonas bacteria are famous about function of bioremediation. They can metabolism the environmental hazardous chemicals like gas oils, dyes, and organic solvents. Our research based on the Pseudomonas putida F1 strain, because its ability to degrade halogenated hydrocarbons such as trichloroethylene. Several methods were investigated to estimate the rate of biodegradation, such as the measurement of the concentration of the pollutant along the contamination pathway, the microcosm's studies or the compound specific stable isotope analysis. In this area in the Transcarpathian basin we are pioneers in the stable isotope monitoring of biodegradation. The main goal is to find stable isotope fractionation factors by stable isotope analysis, which can help us to estimate the rate and effectiveness of the biodegradation. The subsequent research period includes the investigation of the method, testing its feasibility and adaptation in the environment. Last but not least, the research gives an opportunity to identify the producer of the contaminant based on the stable isotope composition of the contaminant.

  8. Supramolecular complexes of multivalent cholesterol-containing polymers to solubilize carbon nanotubes in apolar organic solvents.

    Science.gov (United States)

    Nguendia, Jules Zeuna; Zhong, Weiheng; Fleury, Alexandre; De Grandpré, Guillaume; Soldera, Armand; Sabat, Ribal Georges; Claverie, Jerome P

    2014-05-01

    Copolymers of 2-ethylhexyl acrylate (EHA) and cholesteryloxycarbonyl-2-hydroxymethacrylate (CEM) were prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization. Supramolecular complexes of these copolymers with carbon nanotubes (CNTs) were soluble in THF, toluene, and isooctane. The colloidal solutions remained stable for months without aggregation. The rationale for the choice of CEM was based on the high adsorption energy of cholesterol on the CNT surface, as computed by DFT calculations. Adsorption isotherms were experimentally measured for copolymers of various architectures (statistical, diblock, and star copolymers), thereby demonstrating that 2-5 cholesterol groups were adsorbed per polymer chain. Once the supramolecular complex had dried, the CNTs could be easily resolubilized in isooctane without the need for high-power sonication and in the absence of added polymer. Analysis by atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) indicated that the CNTs were devoid of bundles. The supramolecular complexes could also be employed in an inverse emulsion polymerization of 2-hydroxyethylmethacrylate (HEMA) in isooctane and dodecane, thereby leading to the formation of a continuous polymeric sheath around the CNTs. Thus, this technique leads to the formation of very stable dispersions in non-polar organic solvents, without altering the fundamental properties of the CNTs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effects of industrial effluents, heavy metals, and organic solvents on mallard embryo development

    Science.gov (United States)

    Hoffman, D.J.; Eastin, W.C.

    1981-01-01

    Mallard eggs were externally exposed at 3 and 8 days of incubation to 7 different industrial effluents and to 7 different heavy metal, organic solvent, and petroleum solutions to screen for potential embryo-toxic effects. This route of exposure was chosen in order to simulate the transfer of pollutant from the plumage of aquatic birds to their eggs. Five of the effluents including mineral pigment, scouring effluent, sludge, and tannery effluent resulted in small but significant reductions in embryonic growth. Treatment with methyl mercury chloride solution of 50 ppm (Hg) impaired embryonic growth but much higher concentrations were required to affect survival and cause teratogenic effects. Oil used to suppress road dust was the most toxic of the pollutants tested and only 0.5 microliter/egg caused 60% mortality by 18 days of development. These findings, in combination with other studies suggest that petroleum pollutants, or effluents in combination with petroleum, may pose a hazard to birds' eggs when exposure is by this route.

  10. Computer Simulations of Molecular Electronic Devices in Vacuum and in Organic Solvents

    Science.gov (United States)

    Wang, Huachuan

    The main aim of this dissertation is to study the structure and dynamics of molecular electronic devices in vacuum and in solvent environment, with special focus on the mechanical properties and cross-section geometries of the break-junction down to the atomic level. The problem statement relies on how to overcome the limitations of observations from experiments, to interpret and reduce the gap between experiential measurements and theoretical studies. In order to reach this goal, a molecular system involving gold nano-electrodes, organic dithiol molecules and a driving-spring model has been built based on the experimental set-up of the break junction (BJ) technique. This technique can be classified as the mechanical controllable break junction (MCBJ) and scanning tunneling / atomic force microscope break junction (STM/AFM-BJ). We then generated self-assembled monolayers and molecular junctions by combining grand-canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulation. These approaches allow us to calibrate the structure and dynamics of molecular junctions under multiple environmental factors simultaneously. In the final stage, conductance calculations are performed using the density functional theory (DFT) in combination with the Green's function techniques. The intermediate molecular junction structures could be used to perform electronic transport calculations to eventually close the force-structure-conductance loop.

  11. Bacterial assisted degradation of chlorpyrifos: The key role of environmental conditions, trace metals and organic solvents.

    Science.gov (United States)

    Khalid, Saira; Hashmi, Imran; Khan, Sher Jamal

    2016-03-01

    Wastewater from pesticide industries, agricultural or surface runoff containing pesticides and their residues has adverse environmental impacts. Present study demonstrates effect of petrochemicals and trace metals on chlorpyrifos (CP) biotransformation often released in wastewater of agrochemical industry. Biodegradation was investigated using bacterial strain Pseudomonas kilonensis SRK1 isolated from wastewater spiked with CP. Optimal environmental conditions for CP removal were CFU (306 × 10(6)), pH (8); initial CP concentration (150 mg/L) and glucose as additional carbon source. Among various organic solvents (petrochemicals) used in this study toluene has stimulatory effect on CP degradation process using SRK1, contrary to this benzene and phenol negatively inhibited degradation process. Application of metal ions (Cu (II), Fe (II) Zn (II) at low concentration (1 mg/L) took part in biochemical reaction and positively stimulated CP degradation process. Metal ions at high concentrations have inhibitory effect on degradation process. A first order growth model was shown to fit the data. It could be concluded that both type and concentration of metal ions and petrochemicals can affect CP degradation process.

  12. Thin-film composite crosslinked polythiosemicarbazide membranes for organic solvent nanofiltration (OSN)

    KAUST Repository

    Aburabie, Jamaliah

    2015-01-01

    In this work we report a new class of solvent stable thin-film composite (TFC) membrane fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate that exhibits superior stability compared with other solvent stable polymeric membranes reported up to now. Integrally skinned asymmetric PTSC membranes were prepared by the phase inversion process and crosslinked with an aromatic bifunctional crosslinker to improve the solvent stability. TFC membranes were obtained via interfacial polymerization using trimesoyl chloride (TMC) and diaminopiperazine (DAP) monomers. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and contact angle measurement.The membranes exhibited high fluxes toward solvents like tetrahydrofuran (THF), dimethylformamide (DMF) and dimethylsulfoxide (DMSO) ranging around 20L/m2 h at 5bar with a molecular weight cut off (MWCO) of around 1000g/mol. The PTSC-based thin-film composite membranes are very stable toward polar aprotic solvents and they have potential applications in the petrochemical and pharmaceutical industry.

  13. Selective and reactive hydration of nitriles to amides in water using silver nanoparticles stabilized by organic ligands

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, Koji [Hokkaido University, Division of Materials Science and Engineering, Faculty of Engineering (Japan); Kawakami, Hayato [Miyoshi Oil & Fat Co., Ltd. (Japan); Narushima, Takashi; Yonezawa, Tetsu, E-mail: tetsu@eng.hokudai.ac.jp [Hokkaido University, Division of Materials Science and Engineering, Faculty of Engineering (Japan)

    2015-02-15

    Water-dispersible silver nanoparticles stabilized by silver–carbon covalent bonds were prepared. They exhibited high catalytic activities for the selective hydration of nitriles to amides in water. The activation of a nitrile group by the functional groups of the substrates and the hydrophobic layer on the nanoparticles influenced the catalyzed reaction were confirmed. Alkyl nitriles could also be selectively hydrated.

  14. Correlation between the physicochemical properties of organic solvents and their biocompatibility toward epoxide hydrolase activity in whole-cells of a yeast, Rhodotorulasp

    CSIR Research Space (South Africa)

    Lotter, J

    2004-08-01

    Full Text Available Epoxides are often highly hydrophobic substrates and the presence of an organic co-solvent within an aqueous bioreactor is in such cases indicated. The effect of 40 water-miscible and -immiscible organic solvents on epoxide hydrolase activity...

  15. Strong and Selective Halide Anion Binding by Neutral Halogen-Bonding [2]Rotaxanes in Wet Organic Solvents.

    Science.gov (United States)

    Lim, Jason Y C; Bunchuay, Thanthapatra; Beer, Paul D

    2017-04-03

    The design and construction of neutral interlocked host molecules for anion recognition are rare. Using an active-metal template approach, the preparation of a family of neutral halogen bonding (XB) rotaxanes containing two, three and four iodotriazole groups integrated into the macrocycle and axle components is achieved. In spite of the interlocked hosts' neutrality, such rotaxane systems are capable of binding halide anions strongly and selectively in wet organic solvent mixtures. Importantly, halide-binding strength and selectivity can be modulated by varying the number and position of the halogen bond donor iodotriazole groups within the interlocked cavity; the rotaxane containing the largest number of halogen bond donor groups exhibits the highest halide anion-binding affinities. By varying the percentage of water content in the solvent, neutral XB donor-mediated anion-binding strength is also demonstrated to be highly sensitive to solvent polarity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Peroxidase activity of bacterial cytochrome P450 enzymes: modulation by fatty acids and organic solvents.

    Science.gov (United States)

    Rabe, Kersten S; Erkelenz, Michael; Kiko, Kathrin; Niemeyer, Christof M

    2010-08-01

    The modulation of peroxidase activity by fatty acid additives and organic cosolvents was determined and compared for four bacterial cytochrome P450 enzymes, thermostable P450 CYP119A1, the P450 domain of CYP102A1 (BMP), CYP152A1 (P450(bsbeta)), and CYP101A1 (P450(cam)). Utilizing a high-throughput microplate assay, we were able to readily screen more than 100 combinations of enzymes, additives and cosolvents in a convenient and highly reproducible assay format. We found that, in general, CYP119A1 and BMP showed an increase in peroxidative activity in the presence of fatty acids, whereas CYP152A1 revealed a decrease in activity and CYP101A1 was only slightly affected. In particular, we observed that the conversion of the fluorogenic peroxidase substrate Amplex Red by CYP119A1 and BMP was increased by a factor of 38 or 11, respectively, when isopropanol and lauric acid were present in the reaction mixture. The activity of CYP119A1 could thus be modulated to reach more than 90% of the activity of CYP152A1 without effectors, which is the system with the highest peroxidative activity. For all P450s investigated we found distinctive reactivity patterns, which suggest similarities in the binding site of CYP119A1 and BMP in contrast with the other two proteins studied. Therefore, this study points towards a role of fatty acids as activators for CYP enzymes in addition to being mere substrates. In general, our detailed description of fatty acid- and organic solvent-effects is of practical interest because it illustrates that optimization of modulators and cosolvents can lead to significantly increased yields in biocatalysis.

  17. Long-term occupational exposure to organic solvents affects color vision, contrast sensitivity and visual fields.

    Directory of Open Access Journals (Sweden)

    Thiago Leiros Costa

    Full Text Available The purpose of this study was to evaluate the visual outcome of chronic occupational exposure to a mixture of organic solvents by measuring color discrimination, achromatic contrast sensitivity and visual fields in a group of gas station workers. We tested 25 workers (20 males and 25 controls with no history of chronic exposure to solvents (10 males. All participants had normal ophthalmologic exams. Subjects had worked in gas stations on an average of 9.6 ± 6.2 years. Color vision was evaluated with the Lanthony D15d and Cambridge Colour Test (CCT. Visual field assessment consisted of white-on-white 24-2 automatic perimetry (Humphrey II-750i. Contrast sensitivity was measured for sinusoidal gratings of 0.2, 0.5, 1.0, 2.0, 5.0, 10.0 and 20.0 cycles per degree (cpd. Results from both groups were compared using the Mann-Whitney U test. The number of errors in the D15d was higher for workers relative to controls (p<0.01. Their CCT color discrimination thresholds were elevated compared to the control group along the protan, deutan and tritan confusion axes (p<0.01, and their ellipse area and ellipticity were higher (p<0.01. Genetic analysis of subjects with very elevated color discrimination thresholds excluded congenital causes for the visual losses. Automated perimetry thresholds showed elevation in the 9°, 15° and 21° of eccentricity (p<0.01 and in MD and PSD indexes (p<0.01. Contrast sensitivity losses were found for all spatial frequencies measured (p<0.01 except for 0.5 cpd. Significant correlation was found between previous working years and deutan axis thresholds (rho = 0.59; p<0.05, indexes of the Lanthony D15d (rho=0.52; p<0.05, perimetry results in the fovea (rho= -0.51; p<0.05 and at 3, 9 and 15 degrees of eccentricity (rho= -0.46; p<0.05. Extensive and diffuse visual changes were found, suggesting that specific occupational limits should be created.

  18. A comparison of EDI with solvent-free MALDI and LDI for the analysis of organic pigments.

    Science.gov (United States)

    Kudaka, Ichiro; Asakawa, Daiki; Mori, Kunihiko; Hiraoka, Kenzo

    2008-04-01

    To evaluate the applicability of EDI to material analysis as a new ionization method, a comparison of EDI with solvent-free matrix-assisted laser desorption ionization (MALDI) and laser desorption ionization (LDI) was made for the analysis of organic pigments, e.g. Pigment Yellow 93, Pigment Yellow 180, and Pigment Green 36, as test samples, which are poorly soluble in standard solvents. In EDI, the samples were prepared in two ways: deposition of suspended samples in appropriate solvents and dried on the substrate, and the direct deposition of the powder samples on the substrate. No matrices were used. Both sample preparation methods gave similar mass spectra. Equally strong signals of [M + H](+) and [M - H](-) ions were observed with some fragment ions for azo pigments in the respective positive or negative mode of operation. For the powder sample of the phthalocyanine pigment PG36, M(+*) and [M + H](+) in the positive mode and M(-*) in the negative mode of operation were observed as major ions. Positive-mode, solvent-free MALDI gave M(+), [M + H](+) and [M + Na](+) and negative mode gave [M - H](-) depending on the sample preparation. As solvent-free MALDI, EDI was also found to be an easy-to-operate, versatile method for the samples as received.

  19. Molecular recognition in different environments: β-cyclodextrin dimer formation in organic solvents.

    Science.gov (United States)

    Zhang, Haiyang; Tan, Tianwei; Feng, Wei; van der Spoel, David

    2012-10-25

    Electrostatic and van der Waals interactions as well as entropy contribute to the energetics governing macromolecular complexation in biomolecules. Hydrogen bonds play a particularly important role in such interactions. Here we use molecular dynamics (MD) simulations to investigate the hydrogen bond (HB) orientations of free beta-cyclodextrin (β-CD) and head-to-head dimerization of β-CD monomers with and without guest molecules in different environments, namely, in 10 different solvents covering a wide range of polarity. Potentials of mean force for the dimer dissociation are derived from umbrella sampling simulations, allowing determination of the binding affinity between monomers. The HB orientations are in good agreement with available experimental data in water and dimethyl sulfoxide, yielding confidence in the force field used. HB exchanges at the secondary rim of β-CD are observed with a fast rate in water and with a low rate or even no exchange in other solvents. Orientational preferences of interglucopyranose HBs and their effects on the β-CD structure in these solvents are discussed in detail. Polar solvents with stronger HB accepting abilities can interrupt intermolecular HBs more easily, resulting in a less stable dimer. Guest molecules included in the channel-type cavity strengthen the binding affinity between two monomers to some extent, particularly in polar solvents. Formation of the head-to-head dimer is therefore solvent-dependent and guest-modulated. There is only limited correlation between the dimer binding energies and solvent properties like the dielectric constant. This implies that implicit solvent models will not be capable of predicting important properties like binding energy for other solvents than water without a complete reparameterization. This work provides a deeper comprehension on the properties of β-CD, and implications for the application of cyclodextrins in aqueous and nonaqueous media are discussed.

  20. NMR Chemical Shift Ranges of Urine Metabolites in Various Organic Solvents

    Directory of Open Access Journals (Sweden)

    Benjamin Görling

    2016-09-01

    Full Text Available Signal stability is essential for reliable multivariate data analysis. Urine samples show strong variance in signal positions due to inter patient differences. Here we study the exchange of the solvent of a defined urine matrix and how it affects signal and integral stability of the urinary metabolites by NMR spectroscopy. The exchange solvents were methanol, acetonitrile, dimethyl sulfoxide, chloroform, acetone, dichloromethane, and dimethyl formamide. Some of these solvents showed promising results with a single batch of urine. To evaluate further differences between urine samples, various acid, base, and salt solutions were added in a defined way mimicking to some extent inter human differences. Corresponding chemical shift changes were monitored.

  1. NMR Chemical Shift Ranges of Urine Metabolites in Various Organic Solvents

    Science.gov (United States)

    Görling, Benjamin; Bräse, Stefan; Luy, Burkhard

    2016-01-01

    Signal stability is essential for reliable multivariate data analysis. Urine samples show strong variance in signal positions due to inter patient differences. Here we study the exchange of the solvent of a defined urine matrix and how it affects signal and integral stability of the urinary metabolites by NMR spectroscopy. The exchange solvents were methanol, acetonitrile, dimethyl sulfoxide, chloroform, acetone, dichloromethane, and dimethyl formamide. Some of these solvents showed promising results with a single batch of urine. To evaluate further differences between urine samples, various acid, base, and salt solutions were added in a defined way mimicking to some extent inter human differences. Corresponding chemical shift changes were monitored. PMID:27598217

  2. Great Market Potential of Hydrazine Hydrate

    Institute of Scientific and Technical Information of China (English)

    Shi Yuying

    2007-01-01

    @@ Stable consumption growth worldwide Hydrazine hydrate is an organic chemical raw material with extensive applications. The world's capacity to produce hydrazine hydrate has reached more than 200 thousand t/atoday (based on 100% hydrazine content).

  3. Comprehensive study of the organic-solvent-free CDI-mediated acylation of various nucleophiles by mechanochemistry.

    Science.gov (United States)

    Métro, Thomas-Xavier; Bonnamour, Julien; Reidon, Thomas; Duprez, Anthony; Sarpoulet, Jordi; Martinez, Jean; Lamaty, Frédéric

    2015-09-01

    Acylation reactions are ubiquitous in the synthesis of natural products and biologically active compounds. Unfortunately, these reactions often require the use of large quantities of volatile and/or toxic solvents, either for the reaction, purification or isolation of the products. Herein we describe and discuss the possibility of completely eliminating the use of organic solvents for the synthesis, purification and isolation of products resulting from the acylation of amines and other nucleophiles. Thus, utilisation of N,N'-carbonyldiimidazole (CDI) allows efficient coupling between carboxylic acids and various nucleophiles under solvent-free mechanical agitation, and water-assisted grinding enables both the purification and isolation of pure products. Critical parameters such as the physical state and water solubility of the products, milling material, type of agitation (vibratory or planetary) as well as contamination from wear are analysed and discussed. In addition, original organic-solvent-free conditions are proposed to overcome the limitations of this approach. The calculations of various green metrics are included, highlighting the particularly low environmental impact of this strategy.

  4. The effect of organic solvent, temperature and mixing time on the production of oil from Moringa oleifera seeds

    Science.gov (United States)

    Ghazali, Q.; Yasin, N. H. M.

    2016-06-01

    The effect of three different organic solvent, temperature and mixing time on the production of oil from M.oleifera seeds were studied to evaluate the effectiveness in obtaining the high oil yield based on the percentage of oil production. The modified version of Soxhlet extraction method was carried out to extract the oil from M.oleifera seeds by using hexane, heptane and ethanol as the organic solvent. Among the three solvents, it is found that heptane yield higher oil from M.oleifera seeds with maximum oil yield of 36.37% was obtained followed by hexane and ethanol with 33.89% and 18.46%, respectively. By using heptane as a solvent, the temperature (60oC, 70oC, 80oC) and mixing time (6 h, 7 h, and 8 h) were investigated to ensure the high oil yield over the experimental ranges employed and high oil yield was obtained at 600C for 6 h with percentage oil yield of 36.37%. The fatty acid compositions of M.oleifera seeds oil were analyzed using Gas Chromatography/Mass Spectrometry (GC-MS). The main components of fatty acid contained in the oil extracted from M.oleifera seeds was oleic acid, followed by palmitic acid and arachidic acid, and small amount of behenic acid and margaric acid.

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

    Science.gov (United States)

    Bouchard, Daniel; Hunkeler, Daniel

    2014-01-17

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

  6. Thermodynamic dissociation constant studies of caffeine at different temperatures and in organic water solvent mixture.

    Science.gov (United States)

    Saeeduddin; Khanzada, A W K

    2004-01-01

    Thermodynamic dissociation studies have been carried out potentiometrically at various temperatures from 25 to 50 degrees C and in 10, 20, 30 and 40% v/v dioxane-water solvent mixture at 25 degrees C. The influence of temperature and nature of solvent on dissociation equilibria of caffeine is being investigated. A computer program in GW-BASIC has been used to calculate the pK values.

  7. Organic solvents as risk factor for autoimmune diseases: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Carolina Barragán-Martínez

    Full Text Available BACKGROUND: Genetic and epigenetic factors interacting with the environment over time are the main causes of complex diseases such as autoimmune diseases (ADs. Among the environmental factors are organic solvents (OSs, which are chemical compounds used routinely in commercial industries. Since controversy exists over whether ADs are caused by OSs, a systematic review and meta-analysis were performed to assess the association between OSs and ADs. METHODS AND FINDINGS: The systematic search was done in the PubMed, SCOPUS, SciELO and LILACS databases up to February 2012. Any type of study that used accepted classification criteria for ADs and had information about exposure to OSs was selected. Out of a total of 103 articles retrieved, 33 were finally included in the meta-analysis. The final odds ratios (ORs and 95% confidence intervals (CIs were obtained by the random effect model. A sensitivity analysis confirmed results were not sensitive to restrictions on the data included. Publication bias was trivial. Exposure to OSs was associated to systemic sclerosis, primary systemic vasculitis and multiple sclerosis individually and also to all the ADs evaluated and taken together as a single trait (OR: 1.54; 95% CI: 1.25-1.92; p-value<0.001. CONCLUSION: Exposure to OSs is a risk factor for developing ADs. As a corollary, individuals with non-modifiable risk factors (i.e., familial autoimmunity or carrying genetic factors should avoid any exposure to OSs in order to avoid increasing their risk of ADs.

  8. Effect of Organic Solvent and Resin on Luminescent Capability of SrAl2O4:Eu2+, Dy3+ Phosphor

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Organic substance such as solvent and resin's effect on luminescent capability of SrAl2O4:Eu2+, Dy3+ phosphor was studied. Some organic solvents and resins were selected for experimentation. The results indicate that those organic solvents will not have negative effect on the applied capability of SrAl2O4:Eu2+, Dy3+ phosphor. Adopting the organic resins and covering method, the afterglow luminance of SrAl2O4:Eu2+, Dy3+ phosphor was increased by 85.01% and 82.51%.

  9. An Environmentally-Friendly and Catalytic Procedure for Mukaiyama Aldol Reaction Using Organic Catalyst DBU under Solvent Free Conditions

    Institute of Scientific and Technical Information of China (English)

    SHEN,Zhi-Liang; JI,Shun-Jun; LOH,Teck Peng

    2004-01-01

    @@ Recently, methods based exclusively on organic catalysts have become of major significance in synthetic chemistry.Mukaiyama-aldol reaction, as one of the most important and frequently utilized methods for C-C bond formation, is well documented in literatures recently. A variety of reagents, particularly metal-containing Lewis acids or bases, are known to promote the nucleophilic process. However, many of the reported strategies might have the following limitations from environmental viewpoints: (1) the use of metal-containing catalyst. Some of the catalysts are air or moisture sensitive (such as lithium amide), and crucial reaction conditions are needed; Some of the catalysts derived from poisonous metal (for example: SnCl4, SmI2 etc.) may cause harmful influence on humane body and environment; (2) the use of organic solvent (such as DMF, CH2Cl2 etc.) may bring about environmental pollution and solvent waste.

  10. Solvent templates induced porous metal-organic materials: conformational isomerism and catalytic activity.

    Science.gov (United States)

    Ding, Ran; Huang, Chao; Lu, Jingjing; Wang, Junning; Song, Chuanjun; Wu, Jie; Hou, Hongwei; Fan, Yaoting

    2015-02-16

    Solvent templates induced Co-based metal-organic materials; conformational isomers {[Co2(pdpa)(CH3CN)(H2O)3]·CH3OH·H2O}n (1) and {[Co2(pdpa)(CH3CN)(H2O)3]}n (2) and {[Co5(pdpa)2(μ3-OH)2(H2O)6]·2H2O}n (3) [H4pdpa = 5,5'-(pentane-1,2-diyl)-bis(oxy)diisophthalic acid] were synthesized under the same solvothermal conditions except with different concentrations of cyclic ethers (1,4-dioxane or tetrahydrofuran) as structure-directing agents. Structural transformations from a three-dimensional (3D) framework of 1 containing channels with dimensions of ∼6 Å × 6 Å to a two-dimensional layer structure of 2 consisting of large open channels with a size of ∼15 Å × 8 Å and then to a 3D nonporous framework of 3, resulting from the different concentrations of cyclic ethers, were observed. The anion-π interactions between electron-efficient oxygen atoms of cyclic ethers and electron-deficient dicarboxylic acid aromatic cores in H4pdpa imported into the synthetic process accounted for the conformational change of the ligand H4pdpa and the following structural variations. A systematic investigation was conducted to explore how different concentrations of structure-directing agents affected the frameworks of resultant metal-organic frameworks. Furthermore, 1-3 were shown to be available heterogeneous catalysts for the synthesis of 2-imidazoline and 1,4,5,6-tetrahydropyrimidine derivatives by the cascade cycloaddition reactions of aromatic nitriles with diamines. The results showed that the catalytic activity of 2 was much higher than that of 1 and 3, because of its unique structural features, including accessible catalytic sites and suitable channel size and shape. In addition, a plausible mechanism for these catalytic reactions was proposed, and the reactivity-structure relationship was further clarified.

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

    Science.gov (United States)

    Wang, Jialin; Liang, Ziqi

    2016-08-31

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

  12. Neurological and neurophysiological examinations of workers occupationally exposed to organic solvent mixtures used in the paint and varnish production.

    Science.gov (United States)

    Indulski, J A; Sińczuk-Walczak, H; Szymczak, M; Wesołowski, W

    1996-01-01

    The aim of this work was to examine the nervous system of workers chronically exposed to mixtures of organic solvent at concentrations within or slightly exceeding the MAC values, used in the manufacture of paints and lacquers. The tests were performed on a group of 175 people, 107 men aged 22-59 (x = 41.25), and 68 women aged 20-55 (x = 38.62). The period of employment was x = 17.34 years and cumulative dose index 16.97 for males; for females, the corresponding values were x = 14.75 and x = 11.42, respectively. The control group included 175 people (107 men and 68 women) not exposed to chemicals matched according to sex, age, and work shift distribution. The neurological examinations included subjective and objective examinations of the nervous system, electroencephalographic (EEG) and visual evoked potential (VEP) evaluations. The assessment of organic solvent exposure was performed according to the method described in PN89/Z-04008/07, and the solvent mixtures were shown to contain xylenes, ethyltoluenes, trimethylbenzenes, propylbenzene, ethylbenzene, toluene, aliphatic hydrocarbons and the components of painter's naphtha. The most frequent complaints among the exposed males included headache, vertigo, concentration difficulties, sleep disorders, sleepiness during the day, increased emotional irritability, mood swings with a tendency to anxiety. The objective neurological examinations did not reveal organic lesions in the central or peripheral nervous systems. Generalised and paroxysmal changes were most common recordings in the abnormal EEG. VEP examinations revealed abnormalities, primarily in the latency of the response evoked. The results of this study suggest that exposures to concentrations within MAC values, or below 1.5 of the MAC values of organic solvents mixtures used in the manufacture of paints and lacquers produce subclinical health effect in the nervous system.

  13. Synthesis of Monolithic Fe2O3-Al2O3 Composite Aerogels via Organic Solvent Sublimation Drying

    Directory of Open Access Journals (Sweden)

    Lili Ren

    2016-01-01

    Full Text Available Monolithic Fe2O3-Al2O3 composite aerogels have been prepared successfully via organic solvent sublimation drying method. The results show that a new phase forms when the right amount of ferric oxide is added to the alumina aerogel. From the TEM pictures we can see a shuttle-type structure with the length of about 15 nm forms, which leads to the high surface areas of composited aerogel.

  14. Nutritional Quality and Physicochemical Characteristics of Defatted Bovine Liver Treated by Supercritical Carbon Dioxide and Organic Solvent

    Science.gov (United States)

    Kang, Sung-Won; Kim, Hye-Min; Rahman, M. Shafiur; Kim, Ah-Na; Yang, Han-Sul

    2017-01-01

    Defatted bovine liver (DBL) is a potential source of protein and minerals. Supercritical carbon dioxide (SC-CO2) and a traditional organic solvent method were used to remove lipid from bovine liver, and the quality characteristics of a control bovine liver (CBL), bovine liver defatted by SC-CO2 (DBLSC-CO2) at different pressures, and bovine liver defatted by organic solvent (DBL-OS) were compared. The DBLSC-CO2 samples had significantly higher (p<0.05) protein, amino acid, carbohydrate, and fiber contents than CBL and DBL-OS. There was a higher yield of lipid from CBL when using SC-CO2 than the organic solvent method. SDS-PAGE analysis demonstrated that the CBL and DBLSC-CO2 had protein bands of a similar intensity and area, whereas DBL-OS appeared extremely poor bands or no bands due to the degradation of proteins, particularly in the 50 to 75 kDa and 20 to 25 kDa molecular weight ranges. In addition, DBLSC-CO2 was shown to have superior functional properties in terms of total soluble content, water and oil absorption, and foaming and emulsification properties. Therefore, SC-CO2 treatment offers a nutritionally and environmentally friendly approach for the removal of lipid from high protein food sources. In addition, SC-CO2 may be a better substitute of traditional organic solvent extraction for producing more stable and high quality foods with high-protein, fat-free, and low calorie contents. PMID:28316468

  15. Transforming Suzuki-Miyaura cross-couplings of MIDA boronates into a green technology: no organic solvents.

    Science.gov (United States)

    Isley, Nicholas A; Gallou, Fabrice; Lipshutz, Bruce H

    2013-11-27

    New technology has been developed that enables Suzuki-Miyaura couplings involving widely utilized MIDA boronates to be run in water as the only medium, mainly at room temperature. The protocol is such that no organic solvent is involved at any stage; from the reaction through to product isolation. Hence, using the E factor scale as a measure of greenness, the values for these cross-couplings approach zero.

  16. Surfactant-stabilized small hydrogel particles in oil: hosts for remarkable activation of enzymes in organic solvents.

    Science.gov (United States)

    Das, Dibyendu; Roy, Sangita; Debnath, Sisir; Das, Prasanta Kumar

    2010-04-26

    Hydrogels of amino acid based cationic surfactant having C(16) tails were used to immobilize heme proteins and enzyme. These hydrogel-entrapped proteins/enzyme showed remarkable activation when dispersed in organic solvent. The activation effect (ratio of the activity of the hydrogel-entrapped enzyme in organic solvent to the activity of the native enzyme in water) of cytochrome c increased up to 350-fold with varying protein and gelator concentration. Hydrogel-entrapped hemoglobin and horseradish peroxidase (HRP) also showed markedly improved activity in organic solvent. Alteration in the structure of the gelator and its supramolecular arrangement showed that the protein immobilized within amphiphilic networks with larger interstitial space exhibited higher activation. This striking activation of hydrogel-entrapped proteins stems from the following effects: 1) the hydrophilic domain of the amphiphilic networks facilitates accessibility of the enzyme to the water-soluble substrate. 2) the surfactant, as an integral part of the amphiphilic network, assists in the formation of a distinct interface through which reactants and products are easily transferred between hydrophilic and hydrophobic domains. 3) Surfactant gelators help in the dispersion and stabilization of gel matrix into small particles in organic solvent, which enhances the overall surface area and results in improved mass transfer. The activation was dramatically improved up to 675-fold in the presence of nongelating anionic surfactants that helped in disintegration of the gel into further smaller-sized particles. Interestingly, hydrogel-immobilized HRP exhibited about 2000-fold higher activity in comparison to the activity of the suspended enzyme in toluene. Structural changes of the entrapped enzyme and the morphology of the matrix were investigated to understand the mechanism of this activation.

  17. Inorganic polarography in organic solvents-II: polarographic examination of the molybdenum(V) thiocyanate complex in diethyl ether.

    Science.gov (United States)

    Afghan, B K; Dagnall, R M

    1967-02-01

    A procedure involving the solvent extraction of molybdenum(V) thiocyanate into diethyl ether followed by a direct polarographic examination of the organic phase offers a selective method for the determination of molybdenum down to 0.5 ppm. Only molybdenum, amongst 21 elements examined, is observed to give a reduction wave under the recommended conditions. The method is evaluated with respect to various experimental factors and is applied to the determination of molybdenum in mild and alloy steels.

  18. ``Living polymers'' in organic solvents : stress relaxation in bicopper tetracarboxylate/tert-butyl cyclohexane solutions

    Science.gov (United States)

    Terech, P.; Maldivi, P.; Dammer, C.

    1994-10-01

    Viscoelastic solutions of a bicopper tetracarboxylate complex in tert-butylcyclohexane have been studied by dynamic rheology in a wide range of concentrations (0.5-1.5 % volume fraction). The zero shear viscosity, the elastic modulus, the terminal stress relaxation time and the height of the high-frequency dip, in a Cole-Cole representation of the complex elastic modulus, follow scaling laws. The related exponents are discussed in the context of the physics of “living polymers” : a term used to describe worm-like species undergoing scission/recombination reactions competing mainly with the reptation motions of the chains. The current system, made up of molecular threads (17.5 Å diameter) of Cu2(O2C-CH(C2H5)C4H9)4 in the apolar solvent, is representative of a “living polymer” where, instead of mechanisms involving transient star polymeric crosslinks, a reversible scission mechanism prevails. The dynamics in the high-frequency range evolves from a regime where reptation is the dominant relaxation mechanism to a cross-over regime where “breathing” fluctuations and Rouse motions become important. Large modifications of the stress relaxation function occur for more concentrated systems. The binary system is the first example of a “living polymer” in an organic solvent and exhibits elastic moduli (G ≈ ca. 120 Pa à φ = 1 %) which are at least 20 times larger than those found for the aqueous “living polymer” systems. Les solutions viscoélastiques d'un tétracarboxylate binucléaire de cuivre dans le tert-butylcyclohexane sont étudiées par rhéologie en mode dynamique dans une gamme étendue de concentrations (0,5 %-15,5 %). La viscosité à gradient nul, le module élastique, le temps terminal de relaxation et la hauteur du puits à haute fréquence, dans une représentation Cole-Cole du module élastique complexe, suivent des lois d'échelles. Les exposants correspondants sont discutés dans le contexte de la physique des “polymères vivants

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

    Science.gov (United States)

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

    2016-10-12

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

  20. Effect of organic co-solvents on the solvation enthalpies of amino acids and dipeptides in mixed aqueous solutions

    Science.gov (United States)

    Badelin, V. G.; Tyunina, E. Yu.

    2011-09-01

    Transition enthalpies (Δtr H o) of substances from water to binary solutions were calculated at 298.15 K on the basis of standard dissolution enthalpies (Δsol H o) for six amino acids and five dipeptides in the mixtures of water with organic solvents of various chemical natures. The enthalpy pair coefficients of interaction h xy for biomolecules with organic component of mixture were estimated within the formalism of the McMillan-Mayer theory. The change in the character of the interaction of the components of solution was demonstrated in dependence on the physicochemical properties of the solvent and nature of the side radical of the dissolved bioorganic substance. Quantitative estimation of the type of interaction of the substance with the solvent was performed on the basis of correlation ratios relating the enthalpy characteristics of bioorganic substances to properties of organic cosolvents. It was shown that in the solutions under study, the effects of both the specific (mainly electron donor) and non-specific solvation of amino acids and peptides are observed.

  1. Screening, purification, and characterization of a novel organic solvent-tolerant esterase, Lip2, from Monascus purpureus strain M7.

    Science.gov (United States)

    Kang, Li-Jing; Meng, Zi-Tong; Hu, Chen; Zhang, Yan; Guo, Hai-Lun; Li, Qing; Li, Mu

    2017-03-01

    Organic solvent-tolerant esterases are proven to be excellent biocatalysts in chemical and pharmaceutical industries. A novel organic solvent-tolerant esterase gene, lip2, was isolated from filamentous fungi Monascus purpureus M7. The sequence analysis suggested that lip2 has a conserved "GDSL" motif near the active center. The multiple-sequence alignment and phylogenetic analysis revealed that Lip2 displayed two unique amino-acid sequence motifs that clearly separate it from any other previously described lipase family. After incubation in 20% methanol and ethanol for 3 h, the Lip2 displayed 190 and 180% residual activities, respectively. It retained 99-110% relative activity in 20% (v/v) hydrophilic organic solvents after incubation for 1 day. This esterase showed optimal activity at 40 °C and retained about 70% maximal activity at 60 °C. The enzyme also displayed more than 50% residual activity over a range of pH 5-11. In the presence of most of metal ions or additives, Lip2 retained most of the activity. These unique properties of Lip2 make it a promising as biocatalyst for industrial processes.

  2. Renal and hepatotoxic alterations in adult mice on inhalation of specific mixture of organic solvents.

    Science.gov (United States)

    Ketan, Vaghasia K; Bhavyata, Kalariya; Linzbuoy, George; Hyacinth, Highland N

    2015-12-01

    This study was aimed at investigating alterations in renal and hepatic toxicity induced by exposing to a combination of three solvents, namely, benzene, toluene and xylene in adult mice. The mice were divided into three groups (control, low-dose-treated (450 ppm) and high-dose (675 ppm) groups) using randomization methods. The treated groups were exposed to vapours of a mixture of benzene, toluene and xylene at doses of 450 and 675 ppm, for 6 h day(-1) for a short-term of 7-day exposure period. The study revealed that the solvent exposure resulted in an increase in the weight of liver and kidney as compared to the control. Biochemical analyses indicated a significant decline in the activities of superoxide dismutase and catalase in both the treated groups, with concomitant increase in lipid peroxidation. Liver aminotransferases (alanine aminotransferase and aspartate aminotransferase) were elevated with significant alterations in the levels of protein, creatinine and cholesterol in these tissues upon solvent exposure. Correlated with these changes, serum thyroid hormones T3 and T4 were also significantly altered. This study, therefore, demonstrates that inhalation of vapours from the solvent mixture resulted in significant dose-dependent biochemical and functional changes in the vital tissues (liver and kidney) studied. The study has specific relevance since humans are increasingly being exposed to such solvents due to increased industrial use in such combinations.

  3. ORGANIC-HIGH IONIC STRENGTH AQUEOUS SOLVENT SYSTEMS FOR SPIRAL COUNTER-CURRENT CHROMATOGRAPHY: GRAPHIC OPTIMIZATION OF PARTITION COEFFICIENT.

    Science.gov (United States)

    Zeng, Yun; Liu, Gang; Ma, Ying; Chen, Xiaoyuan; Ito, Yoichiro

    2013-01-10

    A new series of organic-high ionic strength aqueous two-phase solvents systems was designed for separation of highly polar compounds by spiral high-speed counter-current chromatography. A total of 21 solvent systems composed of 1-butanol-ethanol-saturated ammonium sulfate-water at various volume ratios are arranged according to an increasing order of polarity. Selection of the two-phase solvent system for a single compound or a multiple sample mixture can be achieved by two steps of partition coefficient measurements using a graphic method. The capability of the method is demonstrated by optimization of partition coefficient for seven highly polar samples including tartrazine (K=0.77), tryptophan (K=1.00), methyl green (K= 0.93), tyrosine (0.81), metanephrine (K=0.89), tyramine (K=0.98), and normetanephrine (K=0.96). Three sulfonic acid components in D&C Green No. 8 were successfully separated by HSCCC using the graphic selection of the two-phase solvent system.

  4. Solvent resistant nanofiltration membranes

    OpenAIRE

    Dutczak, S.M.

    2011-01-01

    This thesis describes preparation and characterization of membranes for organic solvent filtration (OSF). The main aim was developing membranes for solvent resistant nanofiltration (SRNF) with molecular weight cut-off below 500 g mol-1.

  5. Effects of organic solvent and solution temperature on electrospun polyvinylidene fluoride nanofibers.

    Science.gov (United States)

    Wei, Kai; Kim, Han-Ki; Kimura, Naotaka; Suzuki, Hiroaki; Satou, Hidekazu; Lee, Ki-Hoon; Park, Young-Hwan; Kim, Ick-Soo

    2013-04-01

    In this study, the Poly(vinylidene fluoride-trifluoethylene) (PVDF) electrospun fibers were successfully prepared by electrospinning. Processing parameters, such as solvents and solution temperature were varied to study their influence on fiber dimensions. Electrospun PVDF fibers were characterized by scanning electron microscope (SEM), Fourier transform infrared spectrophotometer (FT-IR), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The result indicated that the solvent component and temperature have great influence on fiber dimensions. 19% PVDF dissolved in DMF/MEK mixed solvents with the ratio of 8:2 was considered to be most suitable in this study. Furthermore, the increasing of solution temperature can probably induce the formation of beta-phases in electrospun PVDF Fibers.

  6. Comparative study of lipid extraction from microalgae by organic solvent and supercritical CO2.

    Science.gov (United States)

    Cheng, Chen-Hsi; Du, Tz-Bang; Pi, Hsien-Chueh; Jang, Shyue-Ming; Lin, Yun-Huin; Lee, Hom-Ti

    2011-11-01

    Pavlova sp. was employed to evaluate the efficiency of different lipid extraction methods. The microalgal crude lipids content determined using the mixed solvent with ultrasonic method was 44.7 wt.%. The triglyceride content obtained by the mixed solvent method was 15.6 wt.%. The extraction yield was the FAME yield divided by the maximum FAME (15.9 wt.%). The extraction yield was improved by cell disruption prior to extraction, and the highest triglyceride extraction yield of 98.7% was observed using the supercritical fluid extraction (SFE) method with bead-beating. The results indicate that the SFE method is effective and provides higher selectivity for triglyceride extraction though the total lipid extracted was less than that using solvent extraction. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. The aerobic oxidation of alcohols with a ruthenium porphyrin catalyst in organic and fluorinated solvents.

    Science.gov (United States)

    Korotchenko, Vasily N; Severin, Kay; Gagné, Michel R

    2008-06-01

    Carbonylruthenium tetrakis(pentafluorophenyl)porphyrin Ru(TPFPP)(CO) was utilized for the aerobic oxidation of alcohols. The in situ activation of the catalyst with mCPBA provided a species capable of catalyzing the oxidation of alcohols with molecular oxygen. The choice of solvent and additive was crucial to obtaining high activity and selectivity. Secondary aromatic alcohols were oxidized in the presence of the ruthenium porphyrin and tetrabutyl ammonium hydroxide in the solvent bromotrichloromethane, enabling high yields to be achieved (up to 99%). Alternatively, alcohols could be oxidized in perfluoro(methyldecalin) with the ruthenium porphyrin at higher temperatures (140 degrees C) and elevated oxygen pressures (50 psi).

  8. Application of accelerated solvent extraction in the analysis of organic contaminants, bioactive and nutritional compounds in food and feed.

    Science.gov (United States)

    Sun, Hanwen; Ge, Xusheng; Lv, Yunkai; Wang, Anbang

    2012-05-11

    Accelerated solvent extraction (ASE) has become a popular green extraction technology for different classes of organic contaminants present in numerous kinds of food and feed for food safety. The parameters affecting ASE efficiency and application advancement of ASE in the analysis of organic contaminants, natural toxins compounds as well as bioactive and nutritional compounds in animal origin food, plant origin food and animal feed are reviewed in detail. ASE is a fully automated and reliable extraction technique with many advantages over traditional extraction techniques, so it could be especially useful for routine analyses of pollutants in food and feed.

  9. Organic solvent-free cloud point extraction-like methodology using aggregation of graphene oxide.

    Science.gov (United States)

    Deng, Dongyan; Jiang, Xiaoming; Yang, Lu; Hou, Xiandeng; Zheng, Chengbin

    2014-01-07

    Because of its unique properties and capability of formation of well-dispersed aqueous colloids in aqueous phase, graphene oxide can be used for the efficient preconcentration of heavy metal ions prior to their determination. The complete collection of graphene oxide colloids from water has generally been considered to be insurmountable. Here, graphene oxide aggregation triggered by introducing NaCl was used to develop a novel organic solvent-free cloud point extraction-like method for the determination of trace toxic metals. The graphene oxide sheets were uniformly dispersed in aqueous samples or standard solutions for a fast and efficient adsorption of Pb(II), Cd(II), Bi(III), and Sb(III) owing to its hydrophilic character and the electrostatic repulsion among the graphene oxide sheets, and its aggregation immediately occurred when the electrostatic repulsion was eliminated via adding NaCl to neutralize the excessive negative charges on the surface of graphene oxide sheets. The aggregates of graphene oxide and analytes ions were separated and treated with hydrochloric acid to form a slurry solution. The slurry solution was pumped to mix with KBH4 solution to generate hydrides, which were subsequently separated from the liquid phase and directed to an atomic fluorescence spectrometer or directly introduced to an inductively coupled plasma optical emission spectrometer for detection. On the basis of a 50 mL sample volume, the limits of detection of 0.01, 0.002, 0.01, and 0.006 ng mL(-1) were obtained for Pb, Cd, Bi, and Sb, respectively, when using atomic fluorescence spectrometry, providing 35-, 8-, 36-, and 37-fold improvements over the conventional method. Detection limits of 0.6, 0.15, 0.1, and 1.0 ng mL(-1) were obtained with the use of slurry sampling inductively coupled plasma optical emission spectrometry. The method was applied for analysis of two Certified Reference Materials and three water samples for these elements.

  10. The solvent-extractable organic compounds in the Indonesia biomass burning aerosols - characterization studies

    Science.gov (United States)

    Fang, M.; Zheng, M.; Wang, F.; To, K. L.; Jaafar, A. B.; Tong, S. L.

    The large-scale air pollution episode due to the out-of-control biomass burning for agricultural purposes in Indonesia started in June 1997, has become a severe environmental problem for itself and the neighboring countries. The fire lasted for almost five months. Its impact on the health and ecology in the affected areas is expected to be substantial, costly and possibly long lasting. Air pollution Index as high as 839 has been reported in Malaysia. API is calculated based on the five pollutants: NO 2, SO 2, O 3, CO, and respirable suspended particulates (PM10). It ranges in value from 0 to 500. An index above 101 is considered to be unhealthy and a value over 201 is very unhealthy (Abidin and Shin, 1996). The solvent-extractable organic compounds from four total suspended particulate (TSP) high-volume samples collected in Kuala Lumpur, Malaysia (Stations Pudu and SIRIM) were subjected to characterization - the abundance was determined and biomarkers were identified. Two of the samples were from early September when the fire was less intense, while the other two were from late September when Kuala Lumpur experienced very heavy smoke coverage which could be easily observed from NOAA/AVHRR satellite images. The samples contained mainly aliphatic hydrocarbons such as n-alkanes and triterpanes, alkanoic acids, alkanols, and polycyclic aromatic hydrocarbons. The difference between the early and late September samples was very significant. The total yield increased from 0.6 to 24.3 μg m -3 at Pudu and 1.9 to 20.1 μg m -3 at SIRIM, with increases in concentration in every class. The higher input of vascular plant wax components in the late September samples, when the fire was more intense, was characterized by the distribution patterns of the homologous series n-alkanes, n-alkanoic acids, and n-alkanols, e.g., lower U : R, higher >C 22/C 20/Abas et al., 1995), the present study also showed an absence of conifer tracers in the smoke aerosols indicating tropical wood

  11. Influence of organic solvents on catalytic behaviors and cell morphology of whole-cell biocatalysts for synthesis of 5'-arabinocytosine laurate.

    Directory of Open Access Journals (Sweden)

    Meiyan Yang

    Full Text Available A whole-cell based method was developed for the regioselective synthesis of arabinocytosine laurate. Among the seven kinds of bacteria strains tested in the acylation reaction, Pseudomonas fluorescens gave the highest productivity and a higher 5'-regioselectivity than 99%. Compared with pure organic solvents, the use of organic solvent mixtures greatly promoted the yield of the whole-cell catalyzed reaction, but showed little influence on the 5'-regioselectivity. Of all the tested solvent mixtures, the best reaction result was found in isopropyl ether/pyridine followed by isopentanol/pyridine. However, the whole-cells showed much lower thermostability in isopropyl ether/pyridine than in THF-pyridine. To better understand the toxic effects of the organic solvents on P. fluorescens whole-cells and growing cells were further examined. Significant influences of organic solvents on the biomass of the cells were found, which differed depending on the type of solvents used. SEM analysis visually revealed the changes in the surface morphology of whole-cells and growing cells cultured in media containing various organic solvents, in terms of surface smoothness, bulges and changed cell sizes. Results demonstrated that organic toxicity to cell structure played an important role in whole-cell mediated catalysis.

  12. Influence of Organic Solvents on Catalytic Behaviors and Cell Morphology of Whole-Cell Biocatalysts for Synthesis of 5′-Arabinocytosine Laurate

    Science.gov (United States)

    Yang, Meiyan; Wu, Hui; Lian, Yan; Li, Xiaofeng; Lai, Furao; Zhao, Guanglei

    2014-01-01

    A whole-cell based method was developed for the regioselective synthesis of arabinocytosine laurate. Among the seven kinds of bacteria strains tested in the acylation reaction, Pseudomonas fluorescens gave the highest productivity and a higher 5′-regioselectivity than 99%. Compared with pure organic solvents, the use of organic solvent mixtures greatly promoted the yield of the whole-cell catalyzed reaction, but showed little influence on the 5′-regioselectivity. Of all the tested solvent mixtures, the best reaction result was found in isopropyl ether/pyridine followed by isopentanol/pyridine. However, the whole-cells showed much lower thermostability in isopropyl ether/pyridine than in THF-pyridine. To better understand the toxic effects of the organic solvents on P. fluorescens whole-cells and growing cells were further examined. Significant influences of organic solvents on the biomass of the cells were found, which differed depending on the type of solvents used. SEM analysis visually revealed the changes in the surface morphology of whole-cells and growing cells cultured in media containing various organic solvents, in terms of surface smoothness, bulges and changed cell sizes. Results demonstrated that organic toxicity to cell structure played an important role in whole-cell mediated catalysis. PMID:25136983

  13. Influence of organic solvents on catalytic behaviors and cell morphology of whole-cell biocatalysts for synthesis of 5'-arabinocytosine laurate.

    Science.gov (United States)

    Yang, Meiyan; Wu, Hui; Lian, Yan; Li, Xiaofeng; Lai, Furao; Zhao, Guanglei

    2014-01-01

    A whole-cell based method was developed for the regioselective synthesis of arabinocytosine laurate. Among the seven kinds of bacteria strains tested in the acylation reaction, Pseudomonas fluorescens gave the highest productivity and a higher 5'-regioselectivity than 99%. Compared with pure organic solvents, the use of organic solvent mixtures greatly promoted the yield of the whole-cell catalyzed reaction, but showed little influence on the 5'-regioselectivity. Of all the tested solvent mixtures, the best reaction result was found in isopropyl ether/pyridine followed by isopentanol/pyridine. However, the whole-cells showed much lower thermostability in isopropyl ether/pyridine than in THF-pyridine. To better understand the toxic effects of the organic solvents on P. fluorescens whole-cells and growing cells were further examined. Significant influences of organic solvents on the biomass of the cells were found, which differed depending on the type of solvents used. SEM analysis visually revealed the changes in the surface morphology of whole-cells and growing cells cultured in media containing various organic solvents, in terms of surface smoothness, bulges and changed cell sizes. Results demonstrated that organic toxicity to cell structure played an important role in whole-cell mediated catalysis.

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

    Science.gov (United States)

    Gu, Yanlong; Jérôme, François

    2013-12-21

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-19

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

  16. Human monitoring of exposure to organic solvents. I Benzene, phenol, toluene, cresols and xylenes

    NARCIS (Netherlands)

    Jansen EHJM; de Fluiter P; TOX

    1994-01-01

    In this report the conclusions of a literature study has been summarized concerning the monitoring of the general population to exposure to benzene-like solvents. Since the Dutch population is exposed to concentrations far below the ppm level, the conclusions on the suitability of biomarkers are

  17. The effect of aqueous organic solvents on the dissociation constants and thermodynamic properties of alkanolamines

    NARCIS (Netherlands)

    Hamborg, Espen S.; van Aken, Coen; Versteeg, Geert F.

    2010-01-01

    The dissociation constants of protonated monoethanolamine and N-methyldiethanolamine have been determined in methanol-water, ethanol-water, and t-butanol-water solvents. The alcohol mole fractions were ranging from 0.2 to 0.95 and the temperatures from 283 to 323 K, 283 to 333 K, and at 298.15 K, re

  18. The Economic and Environmental Benefits of Product Substitution for Organic Solvents

    Science.gov (United States)

    1991-05-01

    Solvent) were selected for Phase II evaluation. [ I METAL TYPE I Copper CDAI10 EPT 2 Nickel 200 3 Aluminum AL2024 4 Steel C4340 5 Aluminum AL7075 6...be removed for disposal. Replenish the tank with diluted cleaner. 115 Cleaning Precautions a. Do not use on indium, lead, or other soft metals

  19. Human monitoring of exposure to organic solvents. I Benzene, phenol, toluene, cresols and xylenes

    NARCIS (Netherlands)

    Jansen EHJM; de Fluiter P; TOX

    1994-01-01

    In this report the conclusions of a literature study has been summarized concerning the monitoring of the general population to exposure to benzene-like solvents. Since the Dutch population is exposed to concentrations far below the ppm level, the conclusions on the suitability of biomarkers are ba

  20. The effect of organic solvents on enzyme kinetic parameters of human CYP3A4 and CYP1A2 in vitro.

    Science.gov (United States)

    Rokitta, Dennis; Pfeiffer, Kay; Streich, Christina; Gerwin, Henrik; Fuhr, Uwe

    2013-10-01

    Abstract Enzyme kinetic parameters provide essential quantitative information about characterization of individual steps in drug metabolism. Such enzymes are located in a (partially) aqueous environment. For in vitro measurements potential lipophilic substrates regularly require organic solvents to achieve concentrations sufficient for access of the drug to the binding site of the enzyme. However, solvents may interact with the enzymes. In this study, we investigated the effects of methanol, ethanol, acetonitrile and dimethyl sulfoxide (1% to 4%) on the assessment of km, Vmax and Clint for the metabolism of midazolam via CYP3A4 to 1-hydroxymidazolam and the metabolism of caffeine to paraxanthine via CYP1A2 using expressed enzymes in vitro. The presence of acetonitrile proved the highest apparent Vmax value for paraxanthine formation but the lowest values for 1-hydroxymidazolam formation. The km value for midazolam showed no systematic effects of organic solvents, while for caffeine km was up to 8-fold lower for solvent free samples compared to solvent containing samples. The present example suggests that effects of solvents may considerably influence enzyme kinetic parameters beyond a mere change in apparent activity. These effects illustrate a difference for individual enzyme--substrate pairs, solvents, and solvent concentrations. What remains is the determination to which extent these effects compromise in vitro-in vivo extrapolations, and which solvents are most appropriate.

  1. Application of gas chromatography analysis to quality control of residual organic solvents in clopidogrel bisulphate

    Directory of Open Access Journals (Sweden)

    Pavlović Aleksandar D.

    2014-01-01

    Full Text Available A direct-injection, split-mode capillary gas chromatographic procedure with a flame ionization detection is developed for the analysis of eight solvents used in the synthesis and purification of an anti-thrombotic drug clopidogrel bisulphate. The solvents analyzed were methanol, acetone, dichloromethane (DCM, 2-butanol, cyclohexane, toluene, acetic acid and N, N-dimethyl formamide (DMF. In addition, as a result of dehydration of 2-butanol during drying process, in clopidogrel bisulphate samples, significant amounts of 2-butanol dehydration products (1-butene, cis and trans isomers of 2-butene, 2,2'-oxydibutane and 1-(1-methylpropoxybutane may be detected. The content of each of these volatile products can be evaluated using the same gas-chromatographic method, with quantification based on the response factor established for the chromatographic peak of 2-butanol. For each solvent used in the process of clopidogrel bisulphate preparation, the procedure is validated for selectivity, linearity, recovery, precision, robustness, quantitation limit, and detection limit. All eight solvents plus five 2-butanol degradation products are fully separated. System suitability test is validated, and requirements are set. Based on a large number of result sets, retrospectively, from many different batches analyzed, conclusions were made about process variations and reliability and a lack of consistency was identified in the quality of the active substance from a particular producer source. Multivariate analysis was used as statistical technique to classify samples. From the analyzed set of 11 solvents, 6 of them were preselected based upon their occurrence in the samples and both Principal Component Analysis (PCA and Hierarchical Cluster Analysis (HCA were performed.

  2. Large-area bi-component processing of organic semiconductors by spray deposition and spin coating with orthogonal solvents

    Energy Technology Data Exchange (ETDEWEB)

    Treossi, Emanuele; Liscio, Andrea; Palermo, Vincenzo [Consiglio Nazionale delle Ricerche, Istituto per la Sintesi Organica e la Fotoreattivita, Bologna (Italy); Feng, Xinliang; Muellen, Klaus [Max-Planck Institute for Polymer Research, Mainz (Germany); Samori, Paolo [Universite Louis Pasteur, Nanochemistry Laboratory, ISIS-CNRS, Strasbourg (France); Consiglio Nazionale delle Ricerche, Istituto per la Sintesi Organica e la Fotoreattivita, Bologna (Italy)

    2009-04-15

    Micrometre-thick uniform layers of a polymeric semiconductor (poly(3-hexylthiophene), P3HT) have been fabricated from solution by spray deposition making use of a commercial airbrush. Multi-scale characterization by optical microscopy and atomic force microscopy revealed the formation of smooth layers featuring reproducible patterns of spatially correlated micron-sized holes. This morphology was found to be uniform over the whole sample surface, on millimetre scale. On this micro-patterned P3HT layer an orthogonal solvent (i.e. a solvent which does not dissolve the P3HT) has been employed to deposit either by spin coating or by drop casting a second organic semiconductor. While spin-coated films exhibited nano-crystals of an alkylated perylene tetracarboxy diimide (PDI) preferentially grown into the micro-fabricated holes, drop-cast films displayed crystalline PDI fibres adsorbed on the patterned surface in random positions. (orig.)

  3. Large-area bi-component processing of organic semiconductors by spray deposition and spin coating with orthogonal solvents

    Science.gov (United States)

    Treossi, Emanuele; Liscio, Andrea; Feng, Xinliang; Palermo, Vincenzo; Müllen, Klaus; Samorì, Paolo

    2009-04-01

    Micrometre-thick uniform layers of a polymeric semiconductor (poly(3-hexylthiophene), P3HT) have been fabricated from solution by spray deposition making use of a commercial airbrush. Multi-scale characterization by optical microscopy and atomic force microscopy revealed the formation of smooth layers featuring reproducible patterns of spatially correlated micron-sized holes. This morphology was found to be uniform over the whole sample surface, on millimetre scale. On this micro-patterned P3HT layer an orthogonal solvent (i.e. a solvent which does not dissolve the P3HT) has been employed to deposit either by spin coating or by drop casting a second organic semiconductor. While spin-coated films exhibited nano-crystals of an alkylated perylene tetracarboxy diimide (PDI) preferentially grown into the micro-fabricated holes, drop-cast films displayed crystalline PDI fibres adsorbed on the patterned surface in random positions.

  4. Application of method of organizational congruences to substitution of organic solvents with vegetable agents for cleaning offset printing machine

    Energy Technology Data Exchange (ETDEWEB)

    Salerno, S. [ENEA, Casaccia (Italy). Area Energia Ambiente e Salute; Tartaglia, R. [Unita Sanitaria Locale 10/D, Firenze (Italy); Garzi, S.; Biagioni, A. [Istituto tecnico Leonardo da Vinci, Firenze (Italy)

    1995-06-01

    The aim of this research is the application of the method of organizational congruences before and after the substitution of organic solvents with vegetable agents for the cleaning offset printing machine in order to assess the organizational changes. A solvent free process is the goal of the SUBSPRINT project (Technology Transfer Program of the European Community). In this study it is shown how human and environmental health is improved by using vegetable agents through this change may lead to some other organizational constraints such as the time needed, the monotony and repetitiveness of the technical actions involved. The authors underline that the knowledge of the new technology impact of health help for a better understanding of the resistance to the change and help for a further amelioration of it.

  5. Influência de solventes orgânicos na adsorção de linalol e decanal em sílica gel Influence of organic solvents on adsorption of linalool and decanal on silica gel

    Directory of Open Access Journals (Sweden)

    Adriana Régia Cornélio

    2004-08-01

    Full Text Available Estudou-se a influência de solventes orgânicos (etanol, propanol e acetato de etila na isoterma de adsorção de uma solução-modelo do óleo essencial de laranja em sílica-gel. A solução-modelo constituiu-se de compostos oxigenados (linalol e decanal dissolvidos em d-limoneno (solvente. A influência da temperatura no processo de adsorção foi determinada para sistemas ternário (d-limoneno + linalol + decanal à temperatura de 298,15 K. Para o composto oxigenado decanal, os solventes que mais influenciaram no processo de adsorção foram o etanol e o acetato de etila; já para o linalol, todos os solventes estudados tiveram influência sobre o processo.The influence of organic solvents (ethanol, propanol and ethyl acetate on the isotherm of adsorption of model solutions of orange essential oil on silica gel was investigated. The model solution consisted of oxygenated compounds (linalool and decanal dissolved in d-limoneno. The influence of temperature on the process of adsorption was determined by ternary systems (d-limoneno + linalool + decanal at the temperature of 298,15 K . For the oxygenated compound decanal, the solvents that showed greater influence on the process of adsorption were ethanol and ethyl acetate, and for linalool all of the solvents studied were shown to influence the process.

  6. Organic solvent and temperature-enhanced ion chromatography-high resolution mass spectrometry for the determination of low molecular weight organic and inorganic anions

    Energy Technology Data Exchange (ETDEWEB)

    Gilchrist, Elizabeth S. [Analytical & Environmental Science Division, Department of Forensic & Analytical Science, King’s College London, 150 Stamford Street, London, SE1 9NH (United Kingdom); Nesterenko, Pavel N. [Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart 7001 (Australia); Smith, Norman W. [Analytical & Environmental Science Division, Department of Forensic & Analytical Science, King’s College London, 150 Stamford Street, London, SE1 9NH (United Kingdom); Barron, Leon P., E-mail: leon.barron@kcl.ac.uk [Analytical & Environmental Science Division, Department of Forensic & Analytical Science, King’s College London, 150 Stamford Street, London, SE1 9NH (United Kingdom)

    2015-03-20

    Highlights: • IC selectivity at high contents of organic solvent in eluent and elevated temperature is studied. • Solvent-enhanced IC coupled to high resolution MS is beneficial for sensitive detection of ions. • The first application of IC-HRMS to the detection of low explosives in fingermarks is shown. - Abstract: There has recently been increased interest in coupling ion chromatography (IC) to high resolution mass spectrometry (HRMS) to enable highly sensitive and selective analysis. Herein, the first comprehensive study focusing on the direct coupling of suppressed IC to HRMS without the need for post-suppressor organic solvent modification is presented. Chromatographic selectivity and added HRMS sensitivity offered by organic solvent-modified IC eluents on a modern hyper-crosslinked polymeric anion-exchange resin (IonPac AS18) are shown using isocratic eluents containing 5–50 mM hydroxide with 0–80% methanol or acetonitrile for a range of low molecular weight anions (<165 Da). Comprehensive experiments on IC thermodynamics over a temperature range between 20–45 °C with the eluent containing up to 60% of acetonitrile or methanol revealed markedly different retention behaviour and selectivity for the selected analytes on the same polymer based ion-exchange resin. Optimised sensitivity with HRMS was achieved with as low as 30–40% organic eluent content. Analytical performance characteristics are presented and compared with other IC-MS based works. This study also presents the first application of IC-HRMS to forensic detection of trace low-order anionic explosive residues in latent human fingermarks.

  7. Countermeasures for exhaust prevention of organic solvents at print shop. 1. Removal of organic solvents by activated carbon adsorption method; Insatsu kojo ni okeru yuki yozai haishutsu boshi taisaku. 1. Kasseitan kyuchakuho ni yoru yuki yozai no jokyo

    Energy Technology Data Exchange (ETDEWEB)

    Yano, H. [Shimizu Corp., Tokyo (Japan); Shoda, M. [Tokyo Institute of Technology, Tokyo (Japan). Research Laboratory of Resources Utilization

    1997-05-10

    This paper describes the state of discharge of organic solvents from a print shop and a deodorizing experiment using a deodorizing equipment of activated carbon adsorption type of a bench test scale. The subject existing print shop has a working space volume of 2000 m{sup 3} and total air exhaust volume of 32000 m{sup 3} per hour. The identified main solvents are ethyl acetate, isopropyl alcohol and toluene. Solvent exhaust concentration at a duct was more than two times greater than the exhaust regulation value. The experiment was performed by using an equipment having an adsorption tower filled with activated carbons of particle form and pellet form made from coconut shell respectively. The gas concentration at an inlet to the deodorizing equipment was 394 ppm as the total concentration, exceeding the exhaust regulation value of 200 ppm. It was verified that the activated adsorption process has high removal effect. The break-through time which expresses life of activated carbon was 38 hours for the particle-formed carbon and 29 hours for the pellet-formed carbon when the total outlet gas concentration was set to 10 ppm. If the adsorption continues after the break-through time has been reached, a displacement phenomenon (displacement among constituents due to selective adsorption) can occur. The required length of the adsorption belt was derived. It was verified that the activated carbons can be regenerated and re-used. 10 refs., 5 figs., 2 tabs.

  8. A comparative study of room temperature ionic liquids and their organic solvent mixtures near charged electrodes

    Science.gov (United States)

    Vatamanu, Jenel; Vatamanu, Mihaela; Borodin, Oleg; Bedrov, Dmitry

    2016-11-01

    The structural properties of electrolytes consisting of solutions of ionic liquids in a polar solvent at charged electrode surfaces are investigated using classical atomistic simulations. The studied electrolytes consisted of tetraethylammonium tetrafluoroborate (NEt4-BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate (c2mim-BF4) and 1-octyl-3-methylimidazolium tetrafluoroborate (c8mim-BF4) salts dissolved in acetonitrile solvent. We discuss the influence of electrolyte concentration, chemical structure of the ionic salt, temperature, conducting versus semiconducting nature of the electrode, electrode geometry and surface roughness on the electric double layer structure and capacitance and compare these properties with those obtained for pure room temperature ionic liquids. We show that electrolytes consisting of solutions of ions can behave quite differently from pure ionic liquid electrolytes.

  9. Predicting the Disorder–Order Transition of Solvent-Free Nanoparticle–Organic Hybrid Materials

    KAUST Repository

    Yu, Hsiu-Yu

    2013-07-02

    The transition from a disordered to a face-centered-cubic phase in solvent-free oligomer-tethered nanoparticles is predicted using a density-functional theory for model hard spheres with tethered bead-spring oligomers. The transition occurs without a difference of volume fraction for the two phases, and the phase boundary is influenced by the loss of oligomer configurational entropy relative to an ideal random system in one phase compared with the other. When the particles are localized in the ordered phase, the cooperation of the oligomers in filling the space is hindered. Therefore, shorter oligomers feel a stronger entropic penalty in the ordered solid and favor the disordered phase. Strikingly, we found that the solvent-free system has a later transition than hard spheres for all investigated ratios of oligomer radius of gyration to particle radius. © 2013 American Chemical Society.

  10. Investigation of the effect of organic solvents on kinetic parameters in metal catalyzed reactions

    Directory of Open Access Journals (Sweden)

    GORDANA A. MILOVANOVIC

    2000-03-01

    Full Text Available The effects of acetone and acetonitrile on the kinetic parameters of azorubin S oxidation by hydrogen peroxide catalyzed by manganese(II, pyrocatechol violet oxidation by hydrogen peroxide catalyzed by copper(II, and carminic acid oxidation by hydrogen peroxide catalyzed by copper(II and activated by bifenox, were examined. It was established that the examined solvents exhibit various effects on the kinetic parameters of the above said reactions. In a11 instances a change in the solvent concentration effects both the anthalpy and the entropy contributions to the free activation energy during the transition of the system into the active state, as well as the constant of the active complex formed at this point.

  11. The Efficacy of Passive Ultrasonic Activation of Organic Solvents on Dissolving Two Root Canal Sealers

    Science.gov (United States)

    Trevisan, Letícia; Huerta, Isadora Razzera; Michelon, Carina; Bello, Mariana De Carlo; Pillar, Rafael; Souza Bier, Carlos Alexandre

    2017-01-01

    Introduction: The aim of this in vitro study was to evaluate the dissolving efficacy of eucalyptol and orange oil solvents associated with passive ultrasonic activation (PUA) in zinc oxide-eugenol (ZOE) based and epoxy resin-based root canal sealers. Methods and Materials: Seventy samples of each sealer were prepared and then randomized according to the solvent and the time of the ultrasonic activation (n=5). The mean amount of weight loss of sealers was calculated in percentages and was analyzed by using the Kruskal-Wallis and Bonferroni post-hoc tests. Results: The greatest values of weight loss were obtained with the ZOE sealer groups (P0.05). Conclusion: The application of PUA with essential oils can be an effective method in dissolving ZOE based sealers. PMID:28179919

  12. Validation of Alternatives to High Volatile Organic Compound Solvents Used in Aeronautical Antifriction Bearing Cleaning

    Science.gov (United States)

    2006-10-17

    Rinse – Step 3 Fluid Agitated Tank MIL-PRF-680 (Filtered –10 μ) 5 min. 8 Dry Isopropyl Alcohol Dryer Isopropyl Alcohol As Required 9 Inspection None...Isopropyl Alcohol Dryer 8 Dry Isopropyl Alcohol As Required 9 Inspection None None As Required Neutralize Fingerprints 10 Fluid Agitated Tank...control regulations for effect on the design and operation of pressurized solvent spray equipment. h. Vibro- Tumbling Finishing Mills. Several

  13. Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

    Directory of Open Access Journals (Sweden)

    Martin Obst

    2016-11-01

    Full Text Available A method for the solvent-free photocatalytic conversion of solid and liquid substrates was developed, using a novel rod mill apparatus. In this setup, thin liquid films are realized which is crucial for an effective photocatalytic conversion due to the low penetration depth of light in heterogeneous systems. Several benzylic alcohols were oxidized with riboflavin tetraacetate as photocatalyst under blue light irradiation of the reaction mixture. The corresponding carbonyl compounds were obtained in moderate to good yields.

  14. Determination of terpenoid content in pine by organic solvent extraction and fast-GC analysis

    Directory of Open Access Journals (Sweden)

    Anne Elizabeth Harman-Ware

    2016-01-01

    Full Text Available Terpenoids, naturally occurring compounds derived from isoprene units present in pine oleoresin, are a valuable source of chemicals used in solvents, fragrances, flavors and have shown potential use as a biofuel. This paper describes a method to extract and analyze the terpenoids present in loblolly pine saplings and pine lighter wood. Various extraction solvents were tested over different times and temperatures. Samples were analyzed by pyrolysis-molecular beam mass spectrometry before and after extractions to monitor the extraction efficiency. The pyrolysis studies indicated that the optimal extraction method used a 1:1 hexane/acetone solvent system at 22°C for 1 h. Extracts from the hexane/acetone experiments were analyzed using a low thermal mass modular accelerated column heater for fast-GC/FID analysis. The most abundant terpenoids from the pine samples were quantified, using standard curves, and included the monoterpenes, α- and β- pinene, camphene and δ-carene. Sesquiterpenes analyzed included caryophyllene, humulene and α-bisabolene. Diterpenoid resin acids were quantified in derivatized extractions, including pimaric, isopimaric, levopimaric, palustric, dehydroabietic, abietic and neoabietic acids.

  15. Pressurized solvent extraction of environmental organic compounds in soils using a supercritical fluid extractor

    Energy Technology Data Exchange (ETDEWEB)

    Li, K.; Landriault, M.; Fingas, M. [Emergencies Science Division, Environmement Canada, Environment Technology Centre, Ontario (Canada); Llompart, M. [Universidad de Santiago de Compostela (Spain). Dept. de Quimica Analitica, Nutricieon y bromatologia, Facultad de Quimica

    1998-11-01

    The applicability of pressurised solvent extraction (PSE) for the quantitative extraction of different of semi-volatiles, including polycyclic aromatic hydrocarbons (PAHs), phenols, polychlorinated biphenyls (PCBs) and total petroleum hydrocarbons have been evaluated. For this study a conventional supercritical fluid extraction (SFE) system, the Suprex SFE/50 was adapted to function as a pressurised solvent extraction system. Solid samples were weighed into the SFE thimble and extracted using conventional extraction solvents instead of superficial carbon dioxide. Parameters such as extraction temperature and effect of modifiers were investigated. Although limited by the 150 deg. C maximum oven temperature, it was found effective extraction could still be carried out in less than 25 min for all the compounds studied. The technique was applied to different real matrices contaminated with hydrocarbons, PAHs and phenols. Validations of the technique were performed using standard reference materials. Recoveries for these matrices were good (> 75 %) and precision was generally less than a 10 % RSD. Extensive comparison of this technique with sonication and with microwave assisted extraction (MAE) were made, and recoveries were found to be comparable to MAE and superior to sonication. (authors) 15 refs.

  16. Solvent-Assisted Metal Metathesis: A Highly Efficient and Versatile Route towards Synthetically Demanding Chromium Metal-Organic Frameworks.

    Science.gov (United States)

    Wang, Jun-Hao; Zhang, Ying; Li, Mian; Yan, Shu; Li, Dan; Zhang, Xian-Ming

    2017-06-01

    Chromium(III)-based metal-organic frameworks (Cr-MOFs) are very attractive in a wide range of investigations because of their robustness and high porosity. However, reports on Cr-MOFs are scarce owing to the difficulties in their direct synthesis. Recently developed postsynthetic routes to obtain Cr-MOFs suffered from complicated procedures and a lack of general applicability. Herein, we report a highly efficient and versatile strategy, namely solvent-assisted metal metathesis, to obtain Cr-MOFs from a variety of Fe(III) -MOFs, including several well-known MOFs and a newly synthesized one, through judicious selection of a coordinating solvent. The versatility of this strategy was demonstrated by producing Cr-MIL-100, Cr-MIL-142A/C, Cr-PCN-333, and Cr-PCN-600 from their Fe(III) analogues and Cr-SXU-1 from a newly synthesized MOF precursor, Fe-SXU-1, in acetone as the solvent under very mild conditions. We have thus developed a general approach for the preparation of robust Cr-MOFs, which are difficult to synthesize by direct methods. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Fabrication of cost effective iron ore slime ceramic membrane for the recovery of organic solvent used in coke production

    Institute of Scientific and Technical Information of China (English)

    V.Singh; N.K.Meena; A.K.Golder; C.Das

    2016-01-01

    Improvement of coking properties of sub-bituminous coal (A) and bituminous coal (B) was done using blended organic solvents,namely,n-methyl-2-pyrrolidinone (NMP) and ethylenediamine (EDA).Various solvent blends were employed for the coal extraction under the total reflux condition.A low-cost ceramic membrane was fabricated using industrial waste iron ore slime of M/s TATA steel R&D,Jamshedpur (India) to separate out the dissolved coking fraction from the solvent-coal mixture.Membrane separations were carried out in a batch cell,and around 75 % recovered NMP was reused.The fractionated coal properties were determined using proximate and ultimate analyses.In the case of bituminous coal,the ash and sulfur contents were decreased by 99.3 % and 79.2 %,respectively,whereas,the carbon content was increased by 23.9 % in the separated coal fraction.Three different cleaning agents,namely deionized water,sodium dodecyl sulphate and NMP were used to regain the original membrane permeability for the reusing.

  18. The role of exhaust ventilation systems in reducing occupational exposure to organic solvents in a paint manufacturing factory

    Directory of Open Access Journals (Sweden)

    Jafari Mohammad

    2008-01-01

    Full Text Available This paper presents the successful design and implementation of several exhaust ventilation systems in a paint manufacturing factory. The ventilation systems were designed based on American Conference of Governmental Industrial Hygienists recommendations. The duct works, fans, and other parts were made and mounted by local manufacturers. The concentrations of toluene and xylene as the common solvents used in paint mixing factories were measured to evaluate the role of ventilation systems in controlling the organic solvents. Occupational exposure to toluene and xylene as the major pollutants was assessed with and without applying ventilation systems. For this purpose, samples were taken from breathing zone of exposed workers using personal samples. The samples were analyzed using Occupational Safety and Health Administration analytical method No.12. The samples were quantified using gas chromatography. The results showed that the ventilation systems successfully controlled toluene and xylene vapors in workplace, air well below the recommended threshold limit value of Iran (44.49 and 97.73 ppm, respectively. It was also discovered that benzene concentration in workplace air was higher than its allowable concentrations. This could be from solvents impurities that require more investigations.

  19. Electro-driven extraction of inorganic anions from water samples and water miscible organic solvents and analysis by ion chromatography.

    Science.gov (United States)

    Nojavan, Saeed; Bidarmanesh, Tina; Memarzadeh, Farkhondeh; Chalavi, Soheila

    2014-09-01

    A simple electromembrane extraction (EME) procedure combined with ion chromatography (IC) was developed to quantify inorganic anions in different pure water samples and water miscible organic solvents. The parameters affecting extraction performance, such as supported liquid membrane (SLM) solvent, extraction time, pH of donor and acceptor solutions, and extraction voltage were optimized. The optimized EME conditions were as follows: 1-heptanol was used as the SLM solvent, the extraction time was 10 min, pHs of the acceptor and donor solutions were 10 and 7, respectively, and the extraction voltage was 15 V. The mobile phase used for IC was a combination of 1.8 mM sodium carbonate and 1.7 mM sodium bicarbonate. Under these optimized conditions, all anions had enrichment factors ranging from 67 to 117 with RSDs between 7.3 and 13.5% (n = 5). Good linearity values ranging from 2 to 1200 ng/mL with coefficients of determination (R(2) ) between 0.987 and 0.999 were obtained. The LODs of the EME-IC method ranged from 0.6 to 7.5 ng/mL. The developed method was applied to different samples to evaluate the feasibility of the method for real applications.

  20. Characterization of inclusion complexes of organic ions with hydrophilic hosts by ion transfer voltammetry with solvent polymeric membranes.

    Science.gov (United States)

    Olmos, José Manuel; Laborda, Eduardo; Ortuño, Joaquín Ángel; Molina, Ángela

    2017-03-01

    The quantitative characterization of inclusion complexes formed in aqueous phase between organic ions and hydrophilic hosts by ion-transfer voltammetry with solvent polymeric membrane ion sensors is studied, both in a theoretical and experimental way. Simple analytical solutions are presented for the determination of the binding constant of the complex from the variation with the host concentration of the electrochemical signal. These solutions are valid for any voltammetric technique and for solvent polymeric membrane ion sensors comprising one polarisable interface (1PI) and also, for the first time, two polarisable interfaces (2PIs). Suitable experimental conditions and data analysis procedures are discussed and applied to the study of the interactions of a common ionic liquid cation (1-octyl-3-metyl-imidazolium) and an ionisable drug (clomipramine) with two hydrophilic cyclodextrins: α-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin. The experimental study is performed via square wave voltammetry with 2PIs and 1PI solvent polymeric membranes and in both cases the electrochemical experiments enable the detection of inclusion complexes and the determination of the corresponding binding constant.

  1. Impact of Organic Solvents and Environmental Pollutants on the Physiological Function in Petrol Filling Workers

    Directory of Open Access Journals (Sweden)

    V. Devender Reddy

    2008-09-01

    Full Text Available Long term exposure to solvents and air pollutants can lead to deleterious effects on respiratory, haematological and thyroid functioning. The aim of this study was to investigate whether chronic exposure to solvents like benzene and pollutants like carbon monoxide in petrol filling workers had adverse effect on blood parameters, thyroid and respiratory functions. The study group consisted of 42 healthy, non-smoker petrol filling workers, aged 20-50 years with work (exposure duration from 2-15 years while 36 healthy subjects of the same age group served as controls. Physical examination and measurement of pulmonary functions by portable electronic spirometer were performed. Complete blood pictures (CBP were determined by normal haematology lab procedure and hormones by Chemiluminescence immunoassay (CLIA light absorption techniques. There was a significant decrease in the lung volumes and capacities; the restrictive pattern was more prevalent in the workers when compared with the control groups. But in the workers exposed for long period (more than 10 years the restrictive pattern was changed to mixed pattern. A significant increase in haemoglobin (Hb (>16 mg % and red blood cells (RBC (5.4 million cells/mm3 were observed in workers with longer period of exposure when compared with the control subjects (14.483 mg% and 4.83 million cells/mm3 for Hb and RBC respectively. White blood cell count except eosinophils and platelets were significantly lower in workers compared to controls. Marked increase in the tetra iodothyroinine (T4, free thyroxine (T4F level and significant decrease in thyroid stimulating hormones (TSH, and tri-iodothyronine (T3 were observed between long term exposed and non – exposed groups. Till now researchers focused only on the effect of solvents in workers professionally exposed to solvents without considering the effect of concomittant air pollution. The result obtained from present study indicates that there is

  2. Effects of Polar Organic Solvent on Separation of Y(edta)-/Nd(edta)- Complexes on Polyacrylic Anion Exchangers

    Institute of Scientific and Technical Information of China (English)

    Halina Hubicka; Dorota Kolodynska

    2005-01-01

    The use of polar organic solvents for the separations of rare earth elements (Ⅲ) is effective especially for their extensive separations despite the solubility limitations. The study shows that polyacrylate anion exchangers, particularly the weakly basic, gel anion exchanger Amberlite IRA 68, can be applied to the separation of rare earth complexes with EDTA in H2O-methanol and H2O-ethanol systems. In most cases the determined distribution coefficients of Ln3+ complexes with EDTA in mixed media like water-methanol on polyacrylate anion exchangers are larger than those in pure water media.

  3. Influence of commercially available polyimide and formation conditions on the performance and structure of asymmetric polyimide organic solvent nanofiltration membranes

    OpenAIRE

    Lopes, Mafalda Pessoa

    2009-01-01

    Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Química e Bioquímica This work covers experimental and theoretical research related to the impact of the polymer structure of commercially available polyimide and polyetherimides as well as the formation conditions on the performance and structure of polyimide Organic Solvent Nanofiltration membranes. The influence in some membrane formation parame...

  4. Gas hydrates

    Digital Repository Service at National Institute of Oceanography (India)

    Ramprasad, T.

    and the role it plays in the global climate and the future of fuels. Russia, Japan, Nigeria, Peru, Chile, Pakistan, Indonesia, Korea, etc are various countries who are perusing the gas hydrates studies as a future resource for fuel. Indian Initiative..., 1993, Free gas at the base of the gas hydrate zone in the vicinity of the Chile Triple junction: Geology, v. 21, pp. 905-908. Borowski, W.S., C.K. Paull, and U. William, III, 1999, Global and local variations of interstitial sulfate gradients...

  5. Influência da temperatura na solubilidade de beta-caroteno em solventes orgânicos à pressão ambiente Effect of temperature on the solubility of beta-carotene in organic solvents under ambient pressure

    Directory of Open Access Journals (Sweden)

    Marcus Vinícius Três

    2007-12-01

    Full Text Available O presente trabalho reporta dados experimentais de solubilidade em pressão ambiente de beta-caroteno em solventes orgânicos puros (etanol, acetona, acetato de etila e diclorometano e em misturas de tais solventes no intervalo de temperatura de 10 a 60 °C. Para este fim, adotou-se o método gravimétrico para a determinação da solubilidade, utilizando células encamisadas de equilíbrio. Os resultados mostraram que valores mais elevados de solubilidade são obtidos quando foram empregados solventes com parâmetros de solubilidade mais próximos daquele do soluto. Verificou-se que o aumento da temperatura, tanto para solventes puros, como para as misturas de solventes, acarretou num aumento da solubilidade do beta-caroteno para todas as condições experimentais. Observou-se ainda, que nas condições experimentais investigadas, não houve sinergismo significativo para as misturas de solventes quando comparadas aos valores de solubilidade obtidos para os solventes puros. O modelo UNIFAC se mostrou útil na previsão qualitativa dos resultados de solubilidade.This work reports experimental data of the solubility of beta-carotene in pure acetone, ethyl acetate, ethanol and dichloromethane and in mixtures of these organic solvents in the temperature range of 10 to 60 °C under ambient pressure. The gravimetric method was employed to determine the solubility, using glass equilibrium cells. The results showed that the best solvents were those having solubility parameter values close to that of the solute. It was found that raising the temperature caused the solute solubility values for both pure and solvent mixtures to increase under all the experimental conditions. Moreover, no synergetic effects were observed on the solubility of beta-carotene in solvent mixtures compared to pure solvents in the temperature range investigated. The UNIFAC model proved to be useful in predicting the solubility data.

  6. Solvent-Assisted Gel Printing for Micropatterning Thin Organic-Inorganic Hybrid Perovskite Films.

    Science.gov (United States)

    Jeong, Beomjin; Hwang, Ihn; Cho, Sung Hwan; Kim, Eui Hyuk; Cha, Soonyoung; Lee, Jinseong; Kang, Han Sol; Cho, Suk Man; Choi, Hyunyong; Park, Cheolmin

    2016-09-27

    While tremendous efforts have been made for developing thin perovskite films suitable for a variety of potential photoelectric applications such as solar cells, field-effect transistors, and photodetectors, only a few works focus on the micropatterning of a perovskite film which is one of the most critical issues for large area and uniform microarrays of perovskite-based devices. Here we demonstrate a simple but robust method of micropatterning a thin perovskite film with controlled crystalline structure which guarantees to preserve its intrinsic photoelectric properties. A variety of micropatterns of a perovskite film are fabricated by either microimprinting or transfer-printing a thin spin-coated precursor film in soft-gel state with a topographically prepatterned elastomeric poly(dimethylsiloxane) (PDMS) mold, followed by thermal treatment for complete conversion of the precursor film to a perovskite one. The key materials development of our solvent-assisted gel printing is to prepare a thin precursor film with a high-boiling temperature solvent, dimethyl sulfoxide. The residual solvent in the precursor gel film makes the film moldable upon microprinting with a patterned PDMS mold, leading to various perovskite micropatterns in resolution of a few micrometers over a large area. Our nondestructive micropatterning process does not harm the intrinsic photoelectric properties of a perovskite film, which allows for realizing arrays of parallel-type photodetectors containing micropatterns of a perovskite film with reliable photoconduction performance. The facile transfer of a micropatterned soft-gel precursor film on other substrates including mechanically flexible plastics can further broaden its applications to flexible photoelectric systems.

  7. Spectrophotometric determination of acidity constants of 2-(2-Thiazolylazo)-Cresol in various water-organic solvent media mixtures using chemometrics methods.

    Science.gov (United States)

    Momeni-Isfahani, Tahereh; Niazi, Ali

    2014-01-01

    The combination of soft- and hard-modeling was used to the spectrophotometric studies of the acidity constants of 2-(2-Thiazolylazo)-Cresol (TAC) at 25°C and at ionic strength 0.1 mol L(-1) in pure water as well as in aqueous media containing variable percentages (10-50%) of organic solvents. The organic solvents used were methanol, ethanol, dimethyl formamide (DMF) and 1,4-dioxane. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program was applied for determining acidity constants and pure spectra of different form of TAC. Results show that the acidity constants of TAC are influenced as the percentages of solvents added to the solution. The corresponding pKa values in solvent-water mixtures were determined. There are linear relationships between acidity constants and the mole fraction of organic solvents in the solvent mixtures. The effects of various solvents on absorption properties and acidity constants of each component are also discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. High-Mobility Ambipolar Organic Thin-Film Transistor Processed From a Nonchlorinated Solvent.

    Science.gov (United States)

    Sonar, Prashant; Chang, Jingjing; Kim, Jae H; Ong, Kok-Haw; Gann, Eliot; Manzhos, Sergei; Wu, Jishan; McNeill, Christopher R

    2016-09-21

    Polymer semiconductor PDPPF-DFT, which combines furan-substituted diketopyrrolopyrrole (DPP) and a 3,4-difluorothiophene base, has been designed and synthesized. PDPPF-DFT polymer semiconductor thin film processed from nonchlorinated hexane is used as an active layer in thin-film transistors. As a result, balanced hole and electron mobilities of 0.26 and 0.12 cm(2)/(V s) are achieved for PDPPF-DFT. This is the first report of using nonchlorinated hexane solvent for fabricating high-performance ambipolar thin-film transistor devices.

  9. Application of acid-catalyzed hydrolysis of dispersed organic solvent in developing new microencapsulation process technology.

    Science.gov (United States)

    Lee, Honghwa; Lee, Sunhwa; Bhattacharjee, Himanshu; Sah, Hongkee

    2012-01-01

    The aim of this study was to evaluate a new microencapsulation technology employing an acid-catalyzed solvent extraction method in conjunction to an emulsion-based microencapsulation process. Its process consisted of emulsifying a dispersed phase of poly(D,L-lactide-co-glycolide) and isopropyl formate in an aqueous phase. This step was followed by adding hydrochloric acid to the resulting oil-in-water emulsion, in order to initiate the hydrolysis of isopropyl formate dissolved in the aqueous phase. Its hydrolysis caused the liberation of water-soluble species, that is, isopropanol and formic acid. This event triggered continual solvent leaching out of emulsion droplets, thereby initiating microsphere solidification. This new processing worked well for encapsulation of progesterone and ketoprofen that were chosen as a nonionizable model drug and a weakly acidic one, respectively. Furthermore, the structural integrity of poly(D,L-lactide-co-glycolide) was retained during microencapsulation. The new microencapsulation technology, being conceptually different from previous approaches, might be useful in preparing various polymeric particles.

  10. 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.

  11. Mechanistic investigations of lipase-catalyzed degradation of polycarbonate in organic solvents.

    Science.gov (United States)

    Artham, Trishul; Mohanalakshmi, N; Paragi-Vedanthi, Padma Priya; Doble, Mukesh

    2011-01-05

    The biodegradation of an engineering thermoplastic, poly (bisphenol-A carbonate) (BPAPC), was carried out using three different lipases from Candida antarctica (CAL), Candida rugosa (CRL) and porcine pancreas (PPL) in water-miscible (tetrahydrofuran) and water-immiscible (chloroform) solvents for 10 days. The degradation was monitored by gel permeation chromatography and Fourier transform infrared spectroscopy. Maximum degradation (ca. 60% reduction in M(n)) of BPAPC was observed in THF with PPL when compared to the control without the enzyme. The degradation products in all the experiments were bisphenol-A and 4-α-cumyl phenol suggesting that the lipases act through an end-chain scission on the polymer. The degradation of BPAPC in THF was in the order of PPL>CAL>CRL, while in CHCl(3) it was CRL>CAL>PPL. To understand this disparity, and to probe the mechanistic aspects of degradation, molecular dynamics investigations were performed on the lipases with model BPAPC in both the solvents. The results also suggested that catalytic triad (Ser, His, Asp/Glu) was involved in the hydrolysis of carbonate bond leading to release of bisphenol-A. These data provide us the basic understanding of the degradation mechanism and a novel methodology for degrading polycarbonate.

  12. Exposure to organic solvents in the offset printing industry in Norway.

    Science.gov (United States)

    Svendsen, K; Rognes, K S

    2000-03-01

    The purpose of this study was to document the conditions regarding solvent exposure at offset printing offices in Norway at present and to study the variation of exposure between printing office technologies. Measurements were made at seven offset printing offices. The measurements consisted of five to 10 whole day personal exposure measurements at each office performed over a period of 2 months. Variables that may influence the level of exposure were registered by the occupational hygienist at the end of each measuring day using a check list. The influence of the variables on the "additive factor" was examined by linear regression analysis.The main contributor to the "additive factor" was isopropanol. The exposure to isopropanol sometimes exceeded the Norwegian TLV. The exposure decreased when a separate exhaust ventilation was used. The exposure increased when the machine had automatic cleaning. The variables automatic cleaning and separate exhaust ventilation explained 59% of the variation in the "additive factor". The results of this study indicate that the most important source of solvent exposure in printing offices at present is the moisturizer used in the printing machines. We think it is worth giving attention to this exposure and making efforts to reduce it.

  13. Extraction of garlic with supercritical CO2 and conventional organic solvents

    Directory of Open Access Journals (Sweden)

    J. M. del Valle

    2008-09-01

    Full Text Available Garlic (Allium sativum L. and garlic extracts have therapeutical properties that stem from their sulfur-containing compounds, mainly allicin. The main objective of this work was to compare conventional and "premium" garlic extracts in terms of yield and quality, with the latter being obtained using supercritical carbon dioxide (SC-CO2 as the solvent. Yield ranged between 0.65 and 1.0% and increased with extraction pressure (150-400 bar at a constant temperature of 50°C. Extraction temperature (35-60°C, on the other hand, had little effect at a constant pressure of 300 bar. Based on yield and quality considerations, the best extraction conditions using SC-CO2 were 35-50°C and 300-400 bar. A yield of 5.5% was obtained by conventional extraction using ethanol as the solvent, but ethanol appeared to be less selective for valuable components than SC-CO2. The use of fresh garlic resulted in extracts that more closely resembled commercial products, possibly because of thermal and oxidative degradation of valuable microconstituents during drying.

  14. A novel organic solvent tolerant lipase from Bacillus sphaericus 205y: extracellular expression of a novel OST-lipase gene.

    Science.gov (United States)

    Sulong, Moohamad Ropaning; Abdul Rahman, Raja Noor Zaliha Raja; Salleh, Abu Bakar; Basri, Mahiran

    2006-10-01

    An organic solvent tolerant (OST) lipase gene from Bacillus sphaericus 205y was successfully expressed extracellularly. The expressed lipase was purified using two steps purification; ultrafiltration and hydrophobic interaction chromatography (HIC) to 8-fold purity and 32% recovery. The purified 205y lipase revealed homogeneity on denaturing gel electrophoresis and the molecular mass was at approximately 30 kDa. The optimum pH for the purified 205y lipase was 7.0-8.0 and its stability showed a broad range of pH value between pH 5.0 to 13.0 at 37 degrees C. The purified 205y lipase exhibited an optimum temperature of 55 degrees C. The activity of the purified lipase was stimulated in the presence of Ca2+ and Mg2+. Ethylenediaminetetraacetic acid (EDTA) has no effect on its activity; however inhibition was observed with phenylmethane sulfonoyl fluoride (PMSF) a serine hydrolase inhibitor. Organic solvents such as dimethylsulfoxide (DMSO), methanol, p-xylene and n-decane enhanced the activity. Studies on the effect of oil showed that the lipase was most active in the presence of tricaprin (C10). The lipase exhibited 1,3 positional specificity. Bacter

  15. A novel electrosynthesis cell with a compressed graphite powder cathode and minimal organic solvent content: Application to the Reformatsky reaction

    Energy Technology Data Exchange (ETDEWEB)

    Areias, Madalena C.C.; Navarro, Marcelo; Bieber, Lothar W.; Diniz, Flamarion B. [Laboratorio de Eletrossintese Organica, DQF CCEN, Universidade Federal de Pernambuco, av. Prof. Luis Freire S/N, 50740-901 Recife (Brazil); Leonel, Eric; Cachet-Vivier, Christine; Nedelec, Jean-Yves [Equipe Electrochimie et Synthese Organique, ICMPE CNRS UMR 7182, Universite Paris 12, 2 rue H. Dunant, 94320 Thiais (France)

    2008-09-20

    A Reformatsky reaction has been employed as a model by which to highlight the advantages of a novel type of undivided electrosynthesis cell working with a content of organic solvent at least 10-times lower than that used in conventional cells. The cathode was formed from compressed graphite powder and was impregnated with a mixture of ethyl 2-bromoisobutyrate and benzaldehyde dissolved in a minimal volume of organic solvent. The cell was filled with aqueous KBr solution, and the electrolysis carried out at a constant potential corresponding to the reduction of the bromoester. Several parameters were optimized with respect to the yield of coupling product, including the ratio of bromoester to benzaldehyde, the pressure of compaction of the electrode powder inside the cavity, and the influence of the cathodic material. Ethyl 2,2-dimethyl-3-hydroxy-3-phenylpropionate was obtained in a yield of up to 86%, and ethyl isobutyrate was the only by-product. A number of other model substrates have been investigated in order to determine the scope and limitations of this new methodology. (author)

  16. Use of gemini surfactants as semipermanent capillary coatings in aqueous-organic solvents for capillary electrophoretic separation of inorganic anions.

    Science.gov (United States)

    Liu, Qian; Li, Yanqing; Yao, Lihua; Yao, Shouzhuo

    2009-12-01

    This paper proposes a new method for CE separation of inorganic anions based on the use of gemini surfactants as capillary coatings in mixed aqueous-organic solvents. The semipermanent gemini surfactant coatings were facilely prepared by rinsing the capillary with 18-s-18 solutions; they can keep be stable during the electrophoretic runs without surfactants in buffer. The coatings showed a good tolerance of methanol (MeOH) or ACN, e.g. at pH 8.0 and with 40% v/v MeOH or ACN, the EOF magnitude after 60 min of continuous electrokinetic rinsing only decreased by 2.9 or 6.0%, respectively. The coatings were successfully applied to the separation of inorganic anions. Adding organic solvents in buffer can effectively improve the resolution and efficiencies; however, it remarkably prolonged the analysis time due to the suppression of EOF. Interestingly, varying the spacer length of the gemini surfactants can also modulate (improve) the resolution but without any sacrifice of analysis time. This benefit was resulted from the unique chemical structures of gemini surfactants because it introduced a new variable, i.e. the spacer length, to the separation mechanism.

  17. Cloning and expression of gene, and activation of an organic solvent-stable lipase from Pseudomonas aeruginosa LST-03.

    Science.gov (United States)

    Ogino, Hiroyasu; Katou, Yoshikazu; Akagi, Rieko; Mimitsuka, Takashi; Hiroshima, Shinichi; Gemba, Yuichi; Doukyu, Noriyuki; Yasuda, Masahiro; Ishimi, Kosaku; Ishikawa, Haruo

    2007-11-01

    Organic solvent-tolerant Pseudomonas aeruginosa LST-03 secretes an organic solvent-stable lipase, LST-03 lipase. The gene of the LST-03 lipase (Lip9) and the gene of the lipase-specific foldase (Lif9) were cloned and expressed in Escherichia coli. In the cloned 2.6 kbps DNA fragment, two open reading frames, Lip9 consisting of 933 nucleotides which encoded 311 amino acids and Lif9 consisting of 1,020 nucleotides which encoded 340 amino acids, were found. The overexpression of the lipase gene (lip9) was achieved when T7 promoter was used and the signal peptide of the lipase was deleted. The expressed amount of the lipase was greatly increased and overexpressed lipase formed inclusion body in E. coli cell. The collected inclusion body of the lipase from the cell was easily solubilized by urea and activated by using lipase-specific foldase of which 52 or 58 amino acids of N-terminal were deleted. Especially, the N-terminal methionine of the lipase of which the signal peptide was deleted was released in E. coli and the amino acid sequence was in agreement with that of the originally-produced lipase by P. aeruginosa LST-03. Furthermore, the overexpressed and solubilized lipase of which the signal peptide was deleted was more effectively activated by lipase-specific foldase.

  18. Laser photolysis study of anthraquinone in binary mixtures ofionic liquid [bmim][PF6] and organic solvent

    Directory of Open Access Journals (Sweden)

    Side Yao

    2006-12-01

    Full Text Available Photochemical properties of the ionic liquid (RTIL 1-butyl-3-methylimidazoliumhexafluorophosphate [bmim][PF6] and its binary mixed solutions with organic solvent(DMF and MeCN were investigated by laser photolysis at an excitation wavelength of 355nm, using anthraquinone (AQ as a probe molecule. It was indicated that the triplet excitedstate of AQ (3AQ* can abstract hydrogen from [bmim][PF6]. Moreover, along with thechange of the ratio of RTIL and organic solvent, the reaction rate constant changes regularly.Critical points were observed at volume fraction VRTIL = 0.2 for RTIL/MeCN and VRTIL =0.05 for RTIL/DMF. For both systems, before the critical point, the rate constant increasesrapidly with increasing VRTIL; however, it decreases obviously with VRTIL after the criticalpoint. We conclude that the concentration dependence is dominant at lower VRTIL, while theviscosity and phase transformation are dominant at higher VRTIL for the effect of ionic liquidon the decay of rate constant.

  19. Preparation of γ-aminopropyltriethoxysilane cross-linked poly(aspartic acid) superabsorbent hydrogels without organic solvent.

    Science.gov (United States)

    Meng, Hongyu; Zhang, Xin; Sun, Shenyu; Tan, Tianwei; Cao, Hui

    2016-01-01

    Poly(aspartic acid) (PASP) hydrogel is a type of biodegradable and biocompatible polymer with high water absorbing ability. Traditionally, the production of PASP hydrogel is expensive, complex, environmentally unfriendly, and consumes a large amount of organic solvents, e.g. dimethylformamide or dimethylsulfoxide. This study introduces a one-step synthesis of PASP resin, in which the organic phase was replaced by distilled water and γ-aminopropyltriethoxysilane was used as the cross-linker. Absorbent ability and characteristics were determined by swelling ratio, FTIR, (13)C SSNMR, and SEM. In vitro cytotoxicity evaluation and animal skin irritation tests showed the hydrogel has body-friendly properties. Preparing PASP hydrogel in aqueous solution is promising and finds its use in many applications.

  20. H-bonding-directed self-assembly of synthetic copolymers containing nucleobases: organization and colloidal fusion in a noncompetitive solvent.

    Science.gov (United States)

    Lutz, Jean-François; Pfeifer, Sebastian; Chanana, Munish; Thünemann, Andreas F; Bienert, Ralf

    2006-08-15

    The self-organization of random copolymers composed of a nucleobase monomer (either 1-(4-vinylbenzyl)thymine or 9-(4-vinylbenzyl)adenine) and dodecyl methacrylate (DMA) was studied in dilute chloroform solutions. The balance between the molar fractions of the nucleobase monomer (leading to intermolecular H-bonding) and DMA (soluble moiety in chloroform) in the polymer chains was found to be the parameter that principally influences the self-organization. DMA-rich copolymers are molecularly soluble in chloroform, whereas nucleobase-rich copolymers are insoluble in this solvent. Copolymers possessing an equimolar comonomer composition self-assemble into micrometer-sized particles physically cross-linked by intermolecular H-bonds (either thymine-thymine or adenine-adenine interactions, depending on the studied copolymer). Nevertheless, when mixed together, thymine- and adenine-based colloids fuse into thermodynamically stable microspheres cross linked by adenine-thymine interactions.

  1. Two-stage dilute-acid and organic-solvent lignocellulosic pretreatment for enhanced bioprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Brodeur, G.; Telotte, J.; Stickel, J. J.; Ramakrishnan, S.

    2016-11-01

    A two stage pretreatment approach for biomass is developed in the current work in which dilute acid (DA) pretreatment is followed by a solvent based pretreatment (N-methyl morpholine N oxide -- NMMO). When the combined pretreatment (DAWNT) is applied to sugarcane bagasse and corn stover, the rates of hydrolysis and overall yields (>90%) are seen to dramatically improve and under certain conditions 48 h can be taken off the time of hydrolysis with the additional NMMO step to reach similar conversions. DAWNT shows a 2-fold increase in characteristic rates and also fractionates different components of biomass -- DA treatment removes the hemicellulose while the remaining cellulose is broken down by enzymatic hydrolysis after NMMO treatment to simple sugars. The remaining residual solid is high purity lignin. Future work will focus on developing a full scale economic analysis of DAWNT for use in biomass fractionation.

  2. Studies on the Surface Interaction and Dispersity of Silver Nanoparticles in Organic Solvents

    Institute of Scientific and Technical Information of China (English)

    ZENG Rong; RONG Min-Zhi; ZHANG Ming-Qiu; ZENG Han-Min

    2000-01-01

    Silver nanoparticles with different sizes have been prepared by microemulsion and have been surface-modified with C12H25SH. Electron spin resonance results indicate that there exist some kinds of surface local paramagnetic sites in capped Ag nanoparticles, which leads to the relation between electron spin resonance parameters and particle size deviating from Kawabata's description. Thereis a strong interaction between nanosilver and chloroform. The smaller the particles, the stronger the interaction. Transmission electron microscopy and ultravilolet-visible absorption spectra confirmed that Ag nanoparticles are well dispersed in chloroform, implying that a good dispersity of Ag nanoparticles in polymers could be obtained by means of solution mixing by using chloroform as the solvent.

  3. The separation of waste printed circuit board by dissolving bromine epoxy resin using organic solvent.

    Science.gov (United States)

    Zhu, P; Chen, Y; Wang, L Y; Zhou, M; Zhou, J

    2013-02-01

    Separation of waste printed circuit boards (WPCBs) has been a bottleneck in WPCBs resource processing. In this study, the separation of WPCBs was performed using dimethyl sulfoxide (DMSO) as a solvent. Various parameters, which included solid to liquid ratio, temperature, WPCB sizes, and time, were studied to understand the separation of WPCBs by dissolving bromine epoxy resin using DMSO. Experimental results showed that the concentration of dissolving the bromine epoxy resin increased with increasing various parameters. The optimum condition of complete separation of WPCBs was solid to liquid ratio of 1:7 and WPCB sizes of 16 mm(2) at 145°C for 60 min. The used DMSO was vapored under the decompression, which obtained the regenerated DMSO and dissolved bromine epoxy resin. This clean and non-polluting technology offers a new way to separate valuable materials from WPCBs and prevent the environmental pollution of waste printed circuit boards effectively.

  4. Enzymatic Lipophilization of Phenolic Acids through Esterification with Fatty Alcohols in Organic Solvents

    DEFF Research Database (Denmark)

    Yang, Zhiyong; Guo, Zheng; Xu, Xuebing

    2012-01-01

    In this study, we investigated and optimized the synthesis of lipophilized esters between selected phenolic acids and fatty alcohols in a binary solvent system, which is composed of hexane and butanone. The effect of different proportion of hexane and butanone was firstly studied by changing...... the volume ratio from 85:15 to 45:55. It was found that the conversion strongly depended on the proportion of hexane and butanone in the reaction system. Following the effect of carbons of fatty alcohol chains on estererification performance with dihydrocaffeic acid (DHCA) was evaluated by choosing different...... fatty alcohols from C4 to C18. The conversion of DHCA was significantly affected by the carbons of fatty alcohol chains. Roughly 95% conversion was achieved within 3 days when DHCA was esterified with hexanol (C6), while only 56% and 44% conversion were achieved when esterified with 1-butanol...

  5. Organic solvent and temperature-enhanced ion chromatography-high resolution mass spectrometry for the determination of low molecular weight organic and inorganic anions.

    Science.gov (United States)

    Gilchrist, Elizabeth S; Nesterenko, Pavel N; Smith, Norman W; Barron, Leon P

    2015-03-20

    There has recently been increased interest in coupling ion chromatography (IC) to high resolution mass spectrometry (HRMS) to enable highly sensitive and selective analysis. Herein, the first comprehensive study focusing on the direct coupling of suppressed IC to HRMS without the need for post-suppressor organic solvent modification is presented. Chromatographic selectivity and added HRMS sensitivity offered by organic solvent-modified IC eluents on a modern hyper-crosslinked polymeric anion-exchange resin (IonPac AS18) are shown using isocratic eluents containing 5-50 mM hydroxide with 0-80% methanol or acetonitrile for a range of low molecular weight anions (<165 Da). Comprehensive experiments on IC thermodynamics over a temperature range between 20-45 °C with the eluent containing up to 60% of acetonitrile or methanol revealed markedly different retention behaviour and selectivity for the selected analytes on the same polymer based ion-exchange resin. Optimised sensitivity with HRMS was achieved with as low as 30-40% organic eluent content. Analytical performance characteristics are presented and compared with other IC-MS based works. This study also presents the first application of IC-HRMS to forensic detection of trace low-order anionic explosive residues in latent human fingermarks.

  6. Insertion of functional groups into a Nd3+ metal-organic framework via single-crystal-to-single-crystal coordinating solvent exchange.

    Science.gov (United States)

    Manos, Manolis J; Kyprianidou, Eleni J; Papaefstathiou, Giannis S; Tasiopoulos, Anastasios J

    2012-06-04

    Single-crystal-to-single-crystal (SCSC) transformations represent some of the most fascinating phenomena in chemistry. They are not only intriguing from a basic science point of view but also provide a means to modify or tune the properties of the materials via the postsynthetic introduction of suitable guest molecules or organic functional groups into their structures. Here, we describe UCY-2, a new flexible Nd(3+) metal-organic framework (MOF), which exhibits a unique capability to undergo a plethora of SCSC transformations with some of them being very uncommon. These structural alterations involve the replacement of coordinating solvent molecules of UCY-2 by terminally ligating solvents and organic ligands with multiple functional groups including -OH, -SH, -NH-, and -NH(2) or their combinations, chelating ligands, anions, and two different organic compounds. The SCSC coordinating solvent exchange is thus demonstrated as a powerful method for the functionalization of MOFs.

  7. The role of organic solvent amount in the lipase-catalyzed biodiesel production O papel da concentração de solvente orgânico na produção enzimática de biodiesel

    Directory of Open Access Journals (Sweden)

    Clarissa Dalla Rosa

    2010-03-01

    Full Text Available This research note addresses the role of organic solvent amount in the production of fatty acid ethyl esters from soybean oil. N-hexane was chosen as solvent and two commercial immobilized lipases as catalysts, Novozym 435 and Lipozyme IM. The reactions were conducted in 6 hours, varying the solvent to oil ratio from zero to 50 (v/wt and adopting adopting for Novozym 435: 65 ºC, enzyme concentration (E, wt% = 5, oil to ethanol molar ratio (R = 1:10, water addition (H, wt% = 0, and for Lipozyme IM: 35 ºC, E = 5 wt%, R = 1:3, H = 10 wt%. For Lipozyme IM, an increase in solvent amount is shown to lead to an enhancement of reaction conversion, while a negligible effect was found for Novozym 435. When using 30 mL of solvent the reaction conversions were 88% for Lipozyme IM and 15% for Novozym 435.O objetivo desta pesquisa é reportar o papel da quantidade do solvente orgânico na produção de ésteres etílicos de ácidos graxos do óleo de soja. O n-hexano foi escolhido como solvente e duas lipases comerciais imobilizadas como catalisadores, Novozym 435 e Lipozyme IM. As reações foram conduzidas em 6 horas, variando a razão de solvente de zero a 50 (v/m, adotando para a Novozym 435: 65 ºC, concentração de enzima (E, m/m% = 5, razão mola óleo:etanol (R = 1:10, adição de água (H, m/m% = 0, e para a Lipozyme IM: 35 ºC, E = 5 m/m%, R = 1:3, H = 10 m/m%. Para a enzima Lipozyme IM, um aumento na quantidade de solvente conduz a uma maior conversão da reação, enquanto um efeito não significativo foi encontrado para a Novozym 435. Com 30 mL de solvente, a conversão encontrada para a Lipozyme IM foi de 88% e 15% para a Novozym 435.

  8. Optimization of physical factors affecting the production of thermo-stable organic solvent-tolerant protease from a newly isolated halo tolerant Bacillus subtilis strain Rand

    Directory of Open Access Journals (Sweden)

    Salleh Abu

    2009-04-01

    Full Text Available Abstract Background Many researchers have reported on the optimization of protease production; nevertheless, only a few have reported on the optimization of the production of organic solvent-tolerant proteases. Ironically, none has reported on thermostable organic solvent-tolerant protease to date. The aim of this study was to isolate the thermostable organic solvent-tolerant protease and identify the culture conditions which support its production. The bacteria of genus Bacillus are active producers of extra-cellular proteases, and the thermostability of enzyme production by Bacillus species has been well-studied by a number of researchers. In the present study, the Bacillus subtilis strain Rand was isolated from the contaminated soil found in Port Dickson, Malaysia. Results A thermostable organic solvent-tolerant protease producer had been identified as Bacillus subtilis strain Rand, based on the 16S rRNA analysis conducted, as well as the morphological characteristics and biochemical properties. The production of the thermostable organic solvent-tolerant protease was optimized by varying various physical culture conditions. Inoculation with 5.0% (v/v of (AB600 = 0.5 inoculum size, in a culture medium (pH 7.0 and incubated for 24 h at 37°C with 200 rpm shaking, was the best culture condition which resulted in the maximum growth and production of protease (444.7 U/ml; 4042.4 U/mg. The Rand protease was not only stable in the presence of organic solvents, but it also exhibited a higher activity than in the absence of organic solvent, except for pyridine which inhibited the protease activity. The enzyme retained 100, 99 and 80% of its initial activity, after the heat treatment for 30 min at 50, 55, and 60°C, respectively. Conclusion Strain Rand has been found to be able to secrete extra-cellular thermostable organic solvent-tolerant protease into the culture medium. The protease exhibited a remarkable stability towards temperature and organic

  9. The effects of exfoliation, organic solvents and anodic activation on the catalytic hydrogen evolution reaction of tungsten disulfide.

    Science.gov (United States)

    Liu, Wanglian; Benson, John; Dawson, Craig; Strudwick, Andrew; Raju, Arun Prakash Aranga; Han, Yisong; Li, Meixian; Papakonstantinou, Pagona

    2017-09-21

    The rational design of transition metal dichalcogenide electrocatalysts for efficiently catalyzing the hydrogen evolution reaction (HER) is believed to lead to the generation of a renewable energy carrier. To this end, our work has made three main contributions. At first, we have demonstrated that exfoliation via ionic liquid assisted grinding combined with gradient centrifugation is an efficient method to exfoliate bulk WS2 to nanosheets with a thickness of a few atomic layers and lateral size dimensions in the range of 100 nm to 2 nm. These WS2 nanosheets decorated with scattered nanodots exhibited highly enhanced catalytic performance for HER with an onset potential of -130 mV vs. RHE, an overpotential of 337 mV at 10 mA cm(-2) and a Tafel slope of 80 mV dec(-1) in 0.5 M H2SO4. Secondly, we found a strong aging effect on the electrocatalytic performance of WS2 stored in high boiling point organic solvents such as dimethylformamide (DMF). Importantly, the HER ability could be recovered by removing the organic (DMF) residues, which obstructed the electron transport, with acetone. Thirdly, we established that the HER performance of WS2 nanosheets/nanodots could be significantly enhanced by activating the electrode surface at a positive voltage for a very short time (60 s), decreasing the kinetic overpotential by more than 80 mV at 10 mA cm(-2). The performance enhancement was found to arise primarily from the ability of a formed proton-intercalated amorphous tungsten trioxide (a-WO3) to provide additional active sites and favourably modify the immediate chemical environment of the WS2 catalyst, rendering it more favorable for local proton delivery and/or transport to the active edge site of WS2. Our results provide new insights into the effects of organic solvents and electrochemical activation on the catalytic performance of two-dimensional WS2 for HER.

  10. Assessment and optimization of an ultrasound-assisted washing process using organic solvents for polychlorinated biphenyl-contaminated soil.

    Science.gov (United States)

    Bezama, Alberto; Flores, Alejandra; Araneda, Alberto; Barra, Ricardo; Pereira, Eduardo; Hernández, Víctor; Moya, Heriberto; Konrad, Odorico; Quiroz, Roberto

    2013-10-01

    The goal of this work was to evaluate a washing process that uses organic solutions for polychlorinated biphenyl (PCB)-contaminated soil, and includes an ultrasound pre-treatment step to reduce operational times and organic solvent losses. In a preliminary trial, the suitability of 10 washing solutions of different polarities were tested, from which three n-hexane-based solutions were selected for further evaluation. A second set of experiments was designed using a three-level Taguchi L27 orthogonal array to model the desorption processes of seven different PCB congeners in terms of the variability of their PCB concentration levels, polarity of the washing solution, sonication time, the ratio washing solution/soil, number of extraction steps and total washing time. Linear models were developed for the desorption processes of all congeners. These models provide a good fit with the results obtained. Moreover, statistically significant outcomes were achieved from the analysis of variance tests carried out. It was determined that sonication time and ratio of washing solution/soil were the most influential process parameters. For this reason they were studied in a third set of experiments, constructed as a full factorial design. The process was eventually optimized, achieving desorption rates of more than 90% for all congeners, thus obtaining concentrations lower than 5 ppb in all cases. The use of an ultrasound-assisted soil washing process for PCB-contaminated soils that uses organic solvents seems therefore to be a viable option, especially with the incorporation of an extra step in the sonication process relating to temperature control, which is intended to prevent the loss of the lighter congeners.

  11. Purification and Characterization of a Lipase with High Thermostability and Polar Organic Solvent-Tolerance from Aspergillus niger AN0512.

    Science.gov (United States)

    Liu, Guang; Hu, Songqing; Li, Lin; Hou, Yi

    2015-11-01

    An extracellular lipase (EC 3.1.1.3, AN0512Lip) from Aspergillus niger AN0512 was purified and its characteristics were investigated. After the process of ammonium sulfate precipitation followed by ion-exchange chromatography and gel filtration, the purified lipase was achieved with 203.6-fold purification and 22.1 % recovery. AN0512Lip exhibited the highest activity at 50 °C and pH 5.0. It was thermostable and pH-stable, as indicated by that more than 50 % activity retained at 60 °C for 20 h and more than 90 % activity retained at pH 3.0 for 20 h, respectively. AN0512Lip activity was stimulated by some divalent metal ions (especially Cu(2+), Ca(2+)), while greatly suppressed by EDTA, indicating that AN0512Lip was a metal-activated enzyme. Moreover, AN0512Lip exhibited high tolerance for various polar organic solvents with log P lipase activity (476 % of its original activity) was achieved after addition of 90 % (V/V) isopropanol to the reaction mixture. AN0512Lip also displayed 3-regiospecificity and great affinity for the long-chain fatty ester. The preliminary test showed that AN0512Lip was a candidate for enriching EPA and DHA in fish oil. All the unique properties, such as thermostability, Cu(2+)-dependent, 3-regiospecificity, and polar organic solvent-tolerance, indicated that AN0512Lip could have potential applications in the food industry, even in organic synthesis and the pharmaceutical industry.

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

    Science.gov (United States)

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

    2015-01-01

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

  13. Antibacterial activity of sequentially extracted organic solvent extracts of fruits, flowers and leaves of Lawsonia inermis L. from Jaffna.

    Science.gov (United States)

    Jeyaseelan, E Christy; Jenothiny, S; Pathmanathan, M K; Jeyadevan, J P

    2012-10-01

    To reveal the antibacterial activity of sequentially extracted different cold organic solvent extracts of fruits, flowers and leaves of Lawsonia inermis (L. against) some pathogenic bacteria. Powders of fruits, flowers and leaves of L. inermis were continuously extracted with dichloromethane (DCM), ethyl acetate and ethanol at ambient temperature. The dried extracts were prepared into different concentrations and tested for antibacterial activity by agar well diffusion method, and also the extracts were tested to determine the available phytochemicals. Except DCM extract of flower all other test extracts revealed inhibitory effect on all tested bacteria and their inhibitory effect differed significantly (Peffect was showed by ethyl acetate extract of flower against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa), and ethyl acetate extract of fruit on Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis). The ethyl acetate and ethanol extracts of flower, fruit and leaf expressed inhibition even at 1 mg/100 µl against all test bacteria. Among the tested phytochemicals flavonoids were detected in all test extracts except DCM extract of flower. The study demonstrated that the ethyl acetate and ethanol extracts of fruit and flower of L. inermis are potentially better source of antibacterial agents compared to leaf extracts of respective solvents.

  14. Purification and characterization of a thermo- and organic solvent-tolerant alkaline protease from Bacillus sp. JER02.

    Science.gov (United States)

    Badoei-Dalfard, Arastoo; Karami, Zahra; Ravan, Hadi

    2015-01-01

    Bacillus sp. JER02 is a bacterial strain that can be grown in a medium containing organic solvents and produce a protease enzyme. JER02 protease was purified with a yield of 31.9% of total protein and 328.83-fold purification. Km and Vmax of this protease were established as 0.826 µM and 7.18 µmol/min, respectively. JER02 protease stability was stimulated about 80% by cyclohexane. It exhibited optimum temperature activity at 70°C. Furthermore, this enzyme was active in a wide range of pH (4-12) and showed maximum activity at pH 9.0. The nonionic detergents Tween-20 and Triton X-100 improved the protease activity by 30 and 20%, respectively. In addition, this enzyme was shown to be very stable in the presence of strong anionic surfactants and oxidizing agents, since it retained 77%, 93%, and 98% of its initial activity, after 1 hr of incubation at room temperature with sodium dodecyl sulfate (SDS), sodium perborate (1%, v/v) and H2O2 (1%, v/v), respectively. Overall, the unique properties of the Bacillus sp. JER02 protease suggested that this thermo- and detergent-stable, solvent-tolerant protease has great potential for industrial applications.

  15. Phosphatidylcholine reverse micelles on the wrong track in molecular dynamics simulations of phospholipids in an organic solvent

    Science.gov (United States)

    Vierros, S.; Sammalkorpi, M.

    2015-03-01

    Here, we examine a well-characterized model system of phospholipids in cyclohexane via molecular dynamics simulations using a force field known for reproducing both phospholipid behavior in water and cyclohexane bulk properties to a high accuracy, CHARMM36, with the aim of evaluating the transferability of a force field parametrization from an aqueous environment to an organic solvent. We compare the resulting reverse micelles with their expected experimental shape and size, and find the model struggles with reproducing basic, experimentally known reverse micellar structural characteristics for common phosphadidylcholine lipids such as 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), 1,2-dioleyl-sn-glycero-3-phosphatidylcholine (DOPC), and 1,2-dilinoleyl-sn-glycero-3-phosphatidylcholine (DLPC) in cyclohexane solvent. We find evidence that the deviation from the experimental behavior originates from an underestimation of the lipid tail-cyclohexane interaction in the model. We compensate for this, obtain reverse micellar structures within the experimentally expected range, and characterize these structurally in molecular detail. Our findings indicate extra caution and verification of model applicability is warranted in simulational studies employing standard biomolecular models outside the usual aqueous environment.

  16. Production, purification and characterization of halophilic organic solvent tolerant protease from marine crustacean shell wastes and its efficacy on deproteinization.

    Science.gov (United States)

    Maruthiah, Thirumalai; Somanath, Beena; Jasmin, Jebamonydhas Vijila; Immanuel, Grasian; Palavesam, Arunachalam

    2016-12-01

    The quantum of marine fish wastes produced by fish processing industries has necessitated to search new methods for its disposal. Hence, this study is focused on production and purification of halophilic organic solvent tolerant protease (HOSP) from marine Alcaligenes faecalis APCMST-MKW6 using marine shell wastes as substrate. The candidate bacterium was isolated from the marine sediment of Manakudi coast and identified as A. faecalis APCMST-MKW6. The purified protease showed 16.39-fold purity, 70.34 U/mg specific activity with 21.67 % yield. The molecular weight of the purified alkaline protease was 49 kDa. This purified protease registered maximum activity at pH 9 and it was stable between pH 8-9 after 1.30 h of incubation. The optimum temperature registered was 60 °C and it was stable between 50 and 60 °C even after 1.30 h of incubation. This enzyme also showed maximum activity at 20 % NaCl concentration. Further, manganese chloride, magnesium chloride, calcium chloride and barium chloride influenced this enzyme activity remarkably and it was also found to be enhanced by many of the tested surfactants and solvents. The candidate bacterium effectively deproteinized the shrimp shell waste compared to the other tested crustaceans shell wastes and also attained maximum antioxidant activity.

  17. Physicochemical and functional properties of rapeseed protein isolate: influence of antinutrient removal with acidified organic solvents from rapeseed meal.

    Science.gov (United States)

    Das Purkayastha, Manashi; Gogoi, Jyotchna; Kalita, Dipankar; Chattopadhyay, Pronobesh; Nakhuru, Khonamai Sewa; Goyary, Danswrang; Mahanta, Charu Lata

    2014-08-06

    The presence of antinutritional constituents in rapeseed protein products (RPI), such as polyphenols, phytates, allyl isothiocyanates, and glucosinolates, is a formidable constraint. The effect of antinutrient removal from rapeseed meal with an organic solvent mixture (methanol/acetone, 1:1 v/v, combined with an acid (hydrochloric, acetic, perchloric, trichloroacetic, phosphoric)) on the physicochemical and functional properties of RPI was investigated. The extraction resulted in a substantial reduction of antinutrients from RPI, especially polyphenols and phytates, with concomitant decreases in protein yield and solubility. Treatment harbored significant improvement in the degree of whiteness, which was highest in the perchloric acid case. Surface hydrophobicity and free sulfhydryl group of RPI changed considerably, with perchloric acid-treated samples showing higher values, whereas the disulfide content remarkably increased in trichloroacetic acid- and phosphoric acid-treated samples, signifying aggregation. Intrinsic emission fluorescence and FTIR spectra showed significant changes in proteins' tertiary and secondary conformations, and the changes were more pronounced in samples treated with higher concentrations of acids. No appreciable alteration appeared among the electrophoretic profiles of proteins from pristine meal and those treated with lower levels of acids. Interfacial surface properties of proteins were variably improved by the solvent extraction, whereas the converse was true for their extent of denaturation. The results suggest that the physicochemical and conformational properties of RPI are closely related to its functional properties.

  18. Antibacterial activity of sequentially extracted organic solvent extracts of fruits, flowers and leaves of Lawsonia inermis L. from Jaffna

    Institute of Scientific and Technical Information of China (English)

    E Christy Jeyaseelan; S Jenothiny; MK Pathmanathan; JP Jeyadevan

    2012-01-01

    To reveal the antibacterial activity of sequentially extracted different cold organic solvent extracts of fruits, flowers and leaves of Lawsonia inermis (L. against) some pathogenic bacteria. Methods: Powders of fruits, flowers and leaves of L. inermis were continuously extracted with dichloromethane (DCM), ethyl acetate and ethanol at ambient temperature. The dried extracts were prepared into different concentrations and tested for antibacterial activity by agar well diffusion method, and also the extracts were tested to determine the available phytochemicals.Results:Except DCM extract of flower all other test extracts revealed inhibitory effect on all tested bacteria and their inhibitory effect differed significantly (P<0.05). The highest inhibitory effect was showed by ethyl acetate extract of flower against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa), and ethyl acetate extract of fruit on Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis). The ethyl acetate and ethanol extracts of flower, fruit and leaf expressed inhibition even at 1 mg/ 100 μl against all test bacteria. Among the tested phytochemicals flavonoids were detected in all test extracts except DCM extract of flower.Conclusions:The study demonstrated that the ethyl acetate and ethanol extracts of fruit and flower of L. inermis are potentially better source of antibacterial agents compared to leaf extracts of respective solvents.

  19. Proton percolation on hydrated lysozyme powders

    OpenAIRE

    Careri, G; Giansanti, A; Rupley, John A.

    1986-01-01

    The framework of percolation theory is used to analyze the hydration dependence of the capacitance measured for protein samples of pH 3-10, at frequencies from 10 kHz to 4 MHz. For all samples there is a critical value of the hydration at which the capacitance sharply increases with increase in hydration level. The threshold hc = 0.15 g of water per g of protein is independent of pH below pH 9 and shows no solvent deuterium isotope effect. The fractional coverage of the surface at hc is in cl...

  20. Absence of association between organic solvent exposure and risk of chronic renal failure: a nationwide population-based case-control study.

    Science.gov (United States)

    Fored, C Michael; Nise, Gun; Ejerblad, Elisabeth; Fryzek, Jon P; Lindblad, Per; McLaughlin, Joseph K; Elinder, Carl-Gustaf; Nyrén, Olof

    2004-01-01

    Exposure to organic solvents has been suggested to cause or exacerbate renal disease, but methodologic concerns regarding previous studies preclude firm conclusions. We examined the role of organic solvents in a population-based case-control study of early-stage chronic renal failure (CRF). All native Swedish residents aged 18 to 74 yr, living in Sweden between May 1996 and May 1998, formed the source population. Incident cases of CRF in a pre-uremic stage (n = 926) and control subjects (n = 998), randomly selected from the study base, underwent personal interviews that included a detailed occupational history. Expert rating by a certified occupational hygienist was used to assess organic solvent exposure intensity and duration. Relative risks were estimated by odds ratios (OR) in logistic regression models, with adjustment for potentially important covariates. The overall risk for CRF among subjects ever exposed to organic solvents was virtually identical to that among never-exposed (OR, 1.01; 95% confidence interval [CI], 0.81 to 1.25). No dose-response relationships were observed for lifetime cumulative solvent exposure, average dose, or exposure frequency or duration. The absence of association pertained to all subgroups of CRF: glomerulonephritis (OR, 0.96; 95% CI, 0.68 to 1.34), diabetic nephropathy (OR, 1.02; 95% CI, 0.74 to 1.41), renal vascular disease (OR, 1.16; 95% CI, 0.76 to 1.75), and other renal CRF (OR, 0.92; 95% CI, 0.66 to 1.27). The results from a nationwide, population-based study do not support the hypothesis of an adverse effect of organic solvents on CRF development, in general. Detrimental effects from subclasses of solvents or on specific renal diseases cannot be ruled out.

  1. Instrument for Solvent Extraction and Analysis (ISEE) of Organics from Regolith Simulant Using Supercritical Fluid Extraction and Chromatography

    Science.gov (United States)

    Franco, Carolina; Hintze, Paul E.

    2017-01-01

    ISEE is an instrument with the potential to perform extractions from regolith found on the surface of asteroids and planets, followed by characterization and quantitation of the extracts using supercritical fluid extraction (SFE) and chromatography (SFC). SFE is a developed technique proven to extract a wide range of organic compounds. SFC is similar to High Performance Liquid Chromatography (HPLC) but has the advantage of performing chiral separations without needing to derivatize the chiral compounds. CO2 will be the solvent for both stages as it is readily available in the Mars atmosphere. ISEE will capture CO2 from the environment, and use it for SFE and SFC. If successful, this would allow ISEE to perform analysis of organic compounds without using consumables. This paper will present results on a preliminary, proof-of-principle effort to use SFE and SFC to extract and analyze lunar regolith simulant spiked with organic compounds representing a range of organics that ISEE would expect to characterize. An optimization of variables for the extraction of the organics from the spiked regolith was successfully developed, using 138 bar pressure and 40 C temperature. The extraction flow rate was optimized at 2% SLPM with 30% methanol modifier. The extractions were successful with a value of 77.3+/- 0.9% of organics extracted. However, the recovery of organics after the extraction was very low with only 48.5+/-14.2%. Moreover, three columns were selected to analyze multiple samples at a time; two of them are Viridis HSS C18 SB and Torus DIOL, and the third column, specific for chiral separations, has not yet been selected yet.

  2. Simultaneous Separation of Manganese, Cobalt, and Nickel by the Organic-Aqueous-Aqueous Three-Phase Solvent Extraction

    Science.gov (United States)

    Shirayama, Sakae; Uda, Tetsuya

    2016-04-01

    This research outlines an organic-aqueous-aqueous three-phase solvent extraction method and proposes its use in a new metal separation process for the recycling of manganese (Mn), cobalt (Co), and nickel (Ni) from used lithium ion batteries (LIBs). The three-phase system was formed by mixing xylene organic solution, 50 pct polyethylene glycol (PEG) aqueous solution, and 1 mol L-1 sodium sulfate (Na2SO4) aqueous solution. The xylene organic solution contained 2-ethylhexylphosphonic acid (D2EHPA) as an extractant for Mn ion, and the Na2SO4 aqueous solution contained 1 mol L-1 potassium thiocyanate (KSCN) as an extractant for Co ion. Concentrations of the metal ions were varied by dissolving metal sulfates in the Na2SO4 aqueous solution. As a result of the experiments, Mn, Co, and Ni ions were distributed in the xylene organic phase, PEG-rich aqueous phase, and Na2SO4-rich aqueous phase, respectively. The separation was effective when the pH value was around 4. Numerical simulation was also conducted in order to predict the distribution of metal ions after the multi-stage counter-current extractions.

  3. Distribution and sources of solvent extractable organic compounds in PM2.5 during 2007 Chinese Spring Festival in Beijing

    Institute of Scientific and Technical Information of China (English)

    LI Xingru; GUO Xueqing; LIU Xinran; LIU Chenshu; ZGHANG Shanshan; WANG Yuesi

    2009-01-01

    The solvent extractable organic compounds (SEOC) including n-alkanes, polycylic aromatic hydrocarbons, fatty acids, and dicarboxylic acids in PM2.5 during the 2007 Chinese Spring Festival in Beijing were measured via gas chromatography to mass spectrometry to determine the characteristics and sources of these organic pollutants. The concentrations of total n-alkanes, PAHs, and organic acids were higher before Chinese Spring Festival Eve (1025.5, 95.9 and 543.3 ng/m3,respectively) than those after (536.6, 58.9, and 331.8 ng/m3, respectively). n-Aalkanes and PAHs had much higher concentration in nighttime than those in daytime because of high relative humidity and low wind speed during the night. Combustion of coal and exhaust emission were major sources of n-alkanes. It could be judged by the characteristic ratios that the primary source of PAHs in fine particles was the combustion of coal, and the combustion of gasoline was in the next place. The ratios of C18:0/C16 indicated the contribution of vehicular emissions to the fatty acids. Dicarboxylic and aromatic acids were abundant in daytime than in nighttime because these acids were secondary organic acid and the photochemical degradation of aromatic hydrocarbons was the main source.

  4. Solvent engineering for high-performance inorganic-organic hybrid perovskite solar cells.

    Science.gov (United States)

    Jeon, Nam Joong; Noh, Jun Hong; Kim, Young Chan; Yang, Woon Seok; Ryu, Seungchan; Seok, Sang Il

    2014-09-01

    Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic cells. Two different cell structures, based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive advances in performance. Here, we report a bilayer architecture comprising the key features of mesoscopic and planar structures obtained by a fully solution-based process. We used CH3NH3 Pb(I(1-x)Br(x))3 (x = 0.1-0.15) as the absorbing layer and poly(triarylamine) as a hole-transporting material. The use of a mixed solvent of γ-butyrolactone and dimethylsulphoxide (DMSO) followed by toluene drop-casting leads to extremely uniform and dense perovskite layers via a CH3NH3I-PbI2-DMSO intermediate phase, and enables the fabrication of remarkably improved solar cells with a certified power-conversion efficiency of 16.2% and no hysteresis. These results provide important progress towards the understanding of the role of solution-processing in the realization of low-cost and highly efficient perovskite solar cells.

  5. Optimization of enzymatic production of biodiesel from castor oil in organic solvent medium.

    Science.gov (United States)

    de Oliveira, Débora; Di Luccio, Marco; Faccio, Carina; Rosa, Clarissa Dalla; Bender, João Paulo; Lipke, Nádia; Menoncin, Silvana; Amroginski, Cristiana; de Oliveira, José Vladimir

    2004-01-01

    We studied the production of fatty acid ethyl esters from castor oil using n-hexane as solvent and two commercial lipases, Novozym 435 and Lipozyme IM, as catalysts. For this purpose, a Taguchi experimental design was adopted considering the following variables: temperature (35-65 degrees C), water (0-10 wt/wt%), and enzyme (5-20 wt/wt%) concentrations and oil-to-ethanol molar ratio (1:3 to 1:10). An empirical model was then built so as to assess the main and cross-variable effects on the reaction conversion and also to maximize biodiesel production for each enzyme. For the system containing Novozym 435 as catalyst the maximum conversion obtained was 81.4% at 65 degrees C, enzyme concentration of 20 wt/wt%, water concentration of 0 wt/wt%, and oil-to-ethanol molar ratio of 1:10. When the catalyst was Lipozyme IM, a conversion as high as 98% was obtained at 65 degrees C, enzyme concentration of 20 wt/wt%, water concentration of 0 wt/wt%, and oil-to-ethanol molar ratio of 1:3.

  6. Solvent engineering for high-performance inorganic-organic hybrid perovskite solar cells

    Science.gov (United States)

    Jeon, Nam Joong; Noh, Jun Hong; Kim, Young Chan; Yang, Woon Seok; Ryu, Seungchan; Seok, Sang Il

    2014-09-01

    Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic cells. Two different cell structures, based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive advances in performance. Here, we report a bilayer architecture comprising the key features of mesoscopic and planar structures obtained by a fully solution-based process. We used CH3NH3 Pb(I1 - xBrx)3 (x = 0.1-0.15) as the absorbing layer and poly(triarylamine) as a hole-transporting material. The use of a mixed solvent of γ-butyrolactone and dimethylsulphoxide (DMSO) followed by toluene drop-casting leads to extremely uniform and dense perovskite layers via a CH3NH3I-PbI2-DMSO intermediate phase, and enables the fabrication of remarkably improved solar cells with a certified power-conversion efficiency of 16.2% and no hysteresis. These results provide important progress towards the understanding of the role of solution-processing in the realization of low-cost and highly efficient perovskite solar cells.

  7. PERTURBATION OF VOLTAGE-SENSITIVE Ca2+ CHANNEL FUNCTION BY VOLATILE ORGANIC SOLVENTS.

    Science.gov (United States)

    The mechanisms underlying the acute neurophysiological and behavioral effects of volatile organic compounds (VOCs) remain to be elucidated. However, the function of neuronal ion channels is perturbed by VOCs. The present study examined effects of toluene (TOL), trichloroethylene ...

  8. PERTURBATION OF VOLTAGE-SENSITIVE Ca2+ CHANNEL FUNCTION BY VOLATILE ORGANIC SOLVENTS.

    Science.gov (United States)

    The mechanisms underlying the acute neurophysiological and behavioral effects of volatile organic compounds (VOCs) remain to be elucidated. However, the function of neuronal ion channels is perturbed by VOCs. The present study examined effects of toluene (TOL), trichloroethylene ...

  9. Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

    National Research Council Canada - National Science Library

    Alves, Célia A

    2008-01-01

    In spite of accounting for 10-70% of the atmospheric aerosol mass, particulate-phase organic compounds are not well characterised, and many aspects of aerosol formation and evolution are still unknown...

  10. 40 CFR Table 5 to Subpart Oooo of... - Default Organic HAP Mass Fraction for Petroleum Solvent Groups a

    Science.gov (United States)

    2010-07-01

    ..., Mineral Spirits 150 EC, Naphtha, Mixed Hydrocarbon, Aliphatic Hydrocarbon, Aliphatic Naphtha, Naphthol Spirits, Petroleum Spirits, Petroleum Oil, Petroleum Naphtha, Solvent Naphtha, Solvent Blend. c Medium-flash Naphtha, High-flash Naphtha, Aromatic Naphtha, Light Aromatic Naphtha, Light Aromatic Hydrocarbons...

  11. Parâmetros reacionais para a síntese enzimática do butirato de butila em solventes orgânicos Reactional parameters for enzymatic synthesis of butyl butyrate in organic solvent

    Directory of Open Access Journals (Sweden)

    Heizir F. CASTRO

    1997-12-01

    Full Text Available A síntese orgânica catalisada por enzimas envolve um mecanismo complexo dependente do tipo de substrato, enzima, solvente orgânico e teor de água no meio reacional. Neste trabalho foi estudado a influência de alguns desses parâmetros no rendimento da esterificação do butanol com ácido butírico, utilizando uma preparação enzimática comercial de lipase. A polaridade e natureza do solvente, bem como a razão molar entre o butanol e ácido butírico, foram considerados os fatores que mais influenciaram o desenvolvimento dessa síntese enzimática.The organic synthesis catalyzed by enzymes is a complex function of substrate concentration, water concentration in the liquid phase, enzyme and organic solvent properties. In this work the influence of some parameters on the esterification of butanol with butyric acid was investigated, using a commercial lipase preparation. The polarity and nature of the solvent and also the substrate mole ratios played an important role in the performance of this enzymatic synthesis.

  12. Simple modification of basic dyes with bulky & symmetric WCAs for improving their solubilities in organic solvents without color change

    Science.gov (United States)

    Kim, Jeong Yun; Hwang, Tae Gyu; Woo, Sung Wun; Lee, Jae Moon; Namgoong, Jin Woong; Yuk, Sim Bum; Chung, Sei-Won; Kim, Jae Pil

    2017-04-01

    A simple and easy solubility enhancement of basic dyes was performed with bulky and symmetric weakly coordinating anions (WCAs). The WCAs decreased the ionic character of the dyes by broadening the partial charge distribution and causing a screening effect on the ionic bonding. This new modification with WCAs has advantages in that it has no influence on the optical properties of the dyes. The solubilities of unmodified and modified dyes were tested in several organic solvents. X-ray powder diffraction patterns of the dyes were measured. Color films were prepared with the dyes and their color loci were analyzed to evaluate the optical properties. By the modification with WCAs, commercial basic dyes showed sufficient solubilities for be applied to various applications while preserving their superior optical properties.

  13. Combination of site-directed mutagenesis and yeast surface display enhances Rhizomucor miehei lipase esterification activity in organic solvent.

    Science.gov (United States)

    Han, Shuang-yan; Zhang, Jun-hui; Han, Zhen-lin; Zheng, Sui-ping; Lin, Ying

    2011-12-01

    To increase the activity of Rhizomucor miehei lipase (RML) in organic solvent, multiple sequence alignments and rational site-directed mutagenesis were used to create RML variants. The obtained proteins were surface-displayed on Pichia pastoris by fusion to Flo1p as an anchor protein. The synthetic activity of four variants showed from 1.1- to 5-fold the activity of native lipase in an esterification reaction in heptane with alcohol and caproic acid as substrates. The increase in esterification activity may be attributed to the four mutations changing the flexibility of RML or facilitating the reaction. In conclusion, this method demonstrated that multiple sequence alignments and rational site-directed mutagenesis combined with yeast display technology is a faster and more effective means of obtaining high-efficiency esterification lipase variants compared with previous similar methods.

  14. Effect of pressure on conformational equilibria of 1-chloropropane and 1-bromopropane in water and organic solvents: a Raman spectroscopic study.

    Science.gov (United States)

    Kasezawa, Kunihiro; Kato, Minoru

    2009-06-25

    We have investigated the effect of pressure on the conformational equilibria of 1-chloropropane and 1-bromopropane in water and organic solvents using Raman spectroscopy. In particular, we focus on 1-chloropropane and 1-bromopropane in water as a model for characterizing the hydrophobic effect on the molecular conformation. From the pressure dependence of the Raman intensities of the carbon-halogen stretching bands, the volume differences (DeltaV(t-->g)) between trans and gauche conformers of 1-chloropropane and 1-bromopropane in water and organic solvents are determined. All the values are found to be negative. The values of DeltaV for aqueous solutions deviate significantly from the expected results obtained for organic solvents. The DeltaV is divided into several contributions and interpretation of these contributions indicates that the significantly large negative DeltaV for aqueous solutions is explained by the considerably low packing density of solvent water compared to the density of the organic solvents. The results for the aqueous solutions are compared with the pressure effect on the dimerization of methane in water calculated by Hummer et al. ( Hummer , G. ; et al. Proc. Natl. Acad. Sci. U.S.A. 1998 , 95 , 1552. ). Our results strongly support the validity of the increasing desolvation barrier with increasing pressure predicted by Hummer et al. Finally, we discuss the biological relevance of the results for aqueous solutions in terms of the pressure denaturation of proteins.

  15. Mechanical properties of wood from Pinus sylvestris L. treated with Light Organic Solvent Preservative and with waterborne Copper Azole

    Directory of Open Access Journals (Sweden)

    A.M. Villasante

    2013-12-01

    Full Text Available Aim of study: To determine the effect on wood from Pinus sylvestris of treatment with preservatives on mechanical properties and to establish the relation between the penetration and compression strength.Area of study: SpainMaterial and Methods: 40 samples of defect-free wood from Pinus sylvestris L. were treated with Light Organic Solvent Preservative (Vacsol Azure WR 2601 and 50 with waterborne Copper Azole (Tanalith E 3492. 40 control samples were not treated (water or preservative. Mechanical resistance to static bending, modulus of elasticity and compression strength parallel to the grain were compared with untreated wood. Regression analysis between the penetration and compression strength parallel was done with the samples treated with waterborne preservative.Main results: The results indicate that the treated wood (with either product presents a statistically significant increase in mechanical resistance in all three mechanical characteristics. The results obtained differ from earlier studies carried out by other authors.There was no correlation between parallel compression strength and the degree of impregnation of the wood with waterborne Copper Azole . The most probable explanation for these results concerns changes in pressure during treatment.The use of untreated control samples instead of samples treated only with water is more likely to produce significant results in the mechanical resistance studies.Research highlights: Treated wood presents a statistically significant increase in MOE, modulus of rupture to static bending  and parallel compression strength.There was no correlation between parallel compression strength and the degree of impregnation with waterborne preservative.Keywords: Light Organic Solvent Preservative; MOE; parallel compression; static bending; waterborne Copper Azole; wood technology.

  16. Polyimide Dielectric Layer on Filaments for Organic Field Effect Transistors: Choice of Solvent, Solution Composition and Dip-Coating Speed

    Directory of Open Access Journals (Sweden)

    Rambausek Lina

    2014-09-01

    Full Text Available In today’s research, smart textiles is an established topic in both electronics and the textile fields. The concept of producing microelectronics directly on a textile substrate is not a mere idea anymore and several research institutes are working on its realisation. Microelectronics like organic field effect transistor (OFET can be manufactured with a layered architecture. The production techniques used for this purpose can also be applied on textile substrates. Besides gate, active and contact layers, the isolating or dielectric layer is of high importance in the OFET architecture. Therefore, generating a high quality dielectric layer that is of low roughness and insulating at the same time is one of the fundamental requirements in building microelectronics on textile surfaces. To evaluate its potential, we have studied polyimide as a dielectric layer, dip-coated onto copper-coated polyester filaments. Accordingly, the copper-coated polyester filament was dip-coated from a polyimide solution with two different solvents, 1-methyl-2-pyrrolidone (NMP and dimethylformaldehyde. A variety of dip-coating speeds, solution concentrations and solvent-solute combinations have been tested. Their effect on the quality of the layer was analysed through microscopy, leak current measurements and atomic force microscopy (AFM. Polyimide dip-coating with polyimide resin dissolved in NMP at a concentration of 15w% in combination with a dip-coating speed of 50 mm/min led to the best results in electrical insulation and roughness. By optimising the dielectric layer’s properties, the way is paved for applying the subsequent semi-conductive layer. In further research, we will be working with the organic semiconductor material TIPS-Pentacene

  17. In-tube electro-membrane extraction with a sub-microliter organic solvent consumption as an efficient technique for synthetic food dyes determination in foodstuff samples.

    Science.gov (United States)

    Bazregar, Mohammad; Rajabi, Maryam; Yamini, Yadollah; Asghari, Alireza; Abdossalami asl, Yousef

    2015-09-04

    A simple and efficient extraction technique with a sub-microliter organic solvent consumption termed as in-tube electro-membrane extraction (IEME) is introduced. This method is based upon the electro-kinetic migration of ionized compounds by the application of an electrical potential difference. For this purpose, a thin polypropylene (PP) sheet placed inside a tube acts as a support for the membrane solvent, and 30μL of an aqueous acceptor solution is separated by this solvent from 1.2mL of an aqueous donor solution. This method yielded high extraction recoveries (63-81%), and the consumption of the organic solvent used was only 0.5μL. By performing this method, the purification is high, and the utilization of the organic solvent, used as a mediator, is very simple and repeatable. The proposed method was evaluated by extraction of four synthetic food dyes (Amaranth, Ponceau 4R, Allura Red, and Carmoisine) as the model analytes. Optimization of variables affecting the method was carried out in order to achieve the best extraction efficiency. These variables were the type of membrane solvent, applied extraction voltage, extraction time, pH range, and concentration of salt added. Under the optimized conditions, IEME-HPLC-UV provided a good linearity in the range of 1.00-800ngmL(-1), low limits of detection (0.3-1ngmL(-1)), and good extraction repeatabilities (RSDs below 5.2%, n=5). It seems that this design is a proper one for the automation of the method. Also the consumption of the organic solvent in a sub-microliter scale, and its simplicity, high efficiency, and high purification can help one getting closer to the objectives of the green chemistry.

  18. INIBIÇÃO DE SALMONELLA POR EXTRATO DE ALECRIM (Rosmarinus officinalis: OBTENÇÃO DE EXTRATOS DE ALECRIM EM SOLVENTES ORGÂNICOS INHIBITION OF Salmonella BY ROSEMARY (Rosmarinus officinalis EXTRACTS: ORGANIC SOLVENTS ROSEMARY EXTRACT OBTENTION

    Directory of Open Access Journals (Sweden)

    Maria Célia Lopes Torres

    2007-09-01

    Full Text Available

    Com o objetivo de se obter um extrato de alecrim em solvente orgânico, a ser utilizado na inibição de Salmonella, em alimentos, foram testados quatro tipos de solventes, a saber: metanol, etanol, acetona e hexano. Na obtenção dos extratos foi adotada a técnica recomendada para determinação de lipídeos, conforme as NORMAS ANALÍTICAS DO INSTITUTO ADOLFO LUTZ (1976. A análise dos resultados evidenciou um excelente desempenho do metanol, não sendo contudo recomendada a utilização em produtos alimentares em virtude da sua toxidez. Também o etanol apresentou elevados índices de extração, sem os inconvenientes associados ao uso do metanol, sendo por isto o solvente indicado para a continuidade do estudo proposto.

    Aiming to obtain a rosemary extract in organic solvent to be used in Salmonella inhibition, in food, were tested four kinds of solvents, namely: methane alcohol, ethyl alcohol, acetone and hexane. It was used the recommended technique for lipids determination in extracts determination according to the analytic rules used by Instituto Adolfo Lutz. Analysis results showed an excellent performance for methane alcohol, but its use is not recommended in feed products due to its toxicity. Ethyl alcohol presented also elevated extraction indexes without inconvenients associated to methane alcohol use, by this reason being a solvent indicated for continuity to the proposed study.

  19. Temporal Variability of Source-Specific Solvent-Extractable Organic Compounds in Coastal Aerosols over Xiamen, China

    Directory of Open Access Journals (Sweden)

    Shuqin Tao

    2017-02-01

    Full Text Available This study describes an analysis of ambient aerosols in a southeastern coastal city of China (Xiamen in order to assess the temporal variability in the concentrations and sources of organic aerosols (OA. Molecular-level measurements based on a series of solvent extractable lipid compounds reveal inherent heterogeneity in OA, in which the concentration and relative contribution of at least three distinct components (terrestrial plant wax derived, marine/microbial and fossil fuel derived organic matter (OM exhibited distinct and systematic temporal variability. Plant wax lipids and associated terrestrial OM are influenced by seasonal variability in plant growth; marine/microbial lipids and associated marine OM are modulated by sea spill and temperature change, whereas fossil fuel derived OM reflects the anthropogenic utilization of fossil fuels originated from petroleum-derived sources and its temporal variation is strongly controlled by meteorological conditions (e.g., the thermal inversion layer, which is analogous to other air organic pollutions. A comparative study among different coastal cities was applied to estimate the supply of different sources of OM to ambient aerosols in different regions, where it was found that biogenic OM in aerosols over Xiamen was much lower than that of other cities; however, petroleum-derived OM exhibited a high level of contribution with a higher concentration of unresolved complex matters (UCM and higher a ratio between UCM and resolved alkanes (UCM/R.

  20. Activity and Enantioselectivity of the Hydroxynitrile Lyase MeHNL in Dry Organic Solvents

    NARCIS (Netherlands)

    Hanefeld, U.; Paravidino, M.; Sorgedrager, M.; Orru, R.V.A.

    2010-01-01

    Water concentration affects both the enantioselectivity and activity of enzymes in dry organic media. Its influence has been investigated using the hydrocyanation of benzaldehyde catalyzed by hydroxynitrile lyase cross-linked enzyme aggregate (MeHNL-CLEA) as a model reaction. The enzyme displayed hi