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Sample records for employs tertiary-amine solvent

  1. Factors influencing phase-disengagement rates in solvent-extraction systems employing tertiary amine extractants

    SciTech Connect

    Moyer, B.A.; McDowell, W.J.

    1981-01-01

    The primary purpose of the present investigation was to examine the effects of amine size and structure on phase disengagement. Nine commercial tertiary amines were tested together with four laboratory-quality amines for uranium extraction and both organic-continuous (OC) and aqueous-continuous (AC) phase disengagement under Amex-type conditions. Synthetic acid sulfate solutions with and without added colloidal silica and actual ore leach solutions were used as the aqueous phases. Phase disengagement results were correlated with amine size and branching and solution wetting behavior on a silicate (glass) surface. The results suggest that the performance of some Amex systems may be improved by using branched chain tertiary amine extractants of higher molecular weight than are now normally used.

  2. Structure-Function Study of Tertiary Amines as Switchable Polarity Solvents

    SciTech Connect

    Aaron D. Wilson; Frederick F. Stewart

    2014-02-01

    A series of tertiary amines have been screened for their function as switchable polarity solvents (SPS). The relative ratios of tertiary amine and carbonate species as well as maximum possible concentration were determined through quantitative 1H and 13C NMR spectroscopy. The viscosities of the polar SPS solutions were measured and ranged from near water in dilute systems through to gel formation at high concentrations. The van't Hoff indices for SPS solutions were measured through freezing point depression studies as a proxy for osmotic pressures. A new form of SPS with an amine : carbonate ratio significantly greater than unity has been identified. Tertiary amines that function as SPS at ambient pressures appear to be limited to molecules with fewer than 12 carbons. The N,N-dimethyl-n-alkylamine structure has been identified as important to the function of an SPS.

  3. Solvent-extraction and purification of uranium(VI) and molybdenum(VI) by tertiary amines from acid leach solutions

    SciTech Connect

    La Gamma, Ana M.G.; Becquart, Elena T.; Chocron, Mauricio

    2008-07-01

    Considering international interest in the yellow-cake price, Argentina is seeking to exploit new uranium ore bodies and processing plants. A study of similar plants would suggest that solvent- extraction with Alamine 336 is considered the best method for the purification and concentration of uranium present in leaching solutions. In order to study the purification of these leach liquors, solvent-extraction tests under different conditions were performed with simulated solutions which containing molybdenum and molybdenum-uranium mixtures. Preliminary extraction tests carried out on mill acid-leaching liquors are also presented. (authors)

  4. Benzoyl peroxide (BPO)-promoted oxidative trifluoromethylation of tertiary amines with trimethyl(trifluoromethyl)silane.

    PubMed

    Chu, Lingling; Qing, Feng-Ling

    2010-09-14

    The benzoyl peroxide (BPO)-promoted oxidative functionalization of tertiary amines under transition-metal-free reaction conditions was developed. Various 1-trifluoromethylated tetrahydroisoquinoline derivatives were prepared by employing this method. It constitutes the first example of direct trifluoromethylation of tertiary amines.

  5. Alkanesulfonylation. XIII. Solvation effects of the solvent on the competing mechanisms of alkanesulfonylation of phenol under conditions of catalysis by tertiary amines

    SciTech Connect

    Bezrodnyi, V.P.; Lyashchuk, S.N.; Skrypnik, Yu.G.

    1988-11-20

    Change in the nature of the solvent leads to a significant change in the ratio of the competing mechanisms in alkanesulfonylation, i.e., the sulfene (1a) and general base catalysis (1b). The most important role here is played by the polarity of the medium, and with increase in the polarity the predominant path changes from (1b) to (1a). In the case of mechanism (1b) the effects of specific solvation show up more strongly than for mechanism (1a). This is due to differences in the structure of the transition states. A quantitative assessment of the solvation effects on the rate of the competing paths (1a, b) is given.

  6. 40 CFR 721.10669 - Tertiary amine alkyl ether (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Tertiary amine alkyl ether (generic... Specific Chemical Substances § 721.10669 Tertiary amine alkyl ether (generic). (a) Chemical substance and... alkyl ether (PMN P-13-78) is subject to reporting under this section for the significant new...

  7. 40 CFR 721.10669 - Tertiary amine alkyl ether (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Tertiary amine alkyl ether (generic... Specific Chemical Substances § 721.10669 Tertiary amine alkyl ether (generic). (a) Chemical substance and... alkyl ether (PMN P-13-78) is subject to reporting under this section for the significant new...

  8. DIRECT SYNTHESIS OF TERTIARY AMINES IN WATER USING MICROWAVES

    EPA Science Inventory

    A direct synthesis of tertiary amines is presented that proceeds expeditiously via N-alkylation of amines using alkyl halides in alkaline aqueous medium. This environmentally benign reaction is accelerated upon exposure to microwave irradiation resulting in shortened reaction tim...

  9. 40 CFR 721.10090 - Tertiary amine salt of glycol succinate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Tertiary amine salt of glycol... Specific Chemical Substances § 721.10090 Tertiary amine salt of glycol succinate (generic). (a) Chemical... as tertiary amine salt of glycol succinate (PMN P-01-595) is subject to reporting under this...

  10. 40 CFR 721.10090 - Tertiary amine salt of glycol succinate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Tertiary amine salt of glycol... Specific Chemical Substances § 721.10090 Tertiary amine salt of glycol succinate (generic). (a) Chemical... as tertiary amine salt of glycol succinate (PMN P-01-595) is subject to reporting under this...

  11. 40 CFR 721.10090 - Tertiary amine salt of glycol succinate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Tertiary amine salt of glycol... Specific Chemical Substances § 721.10090 Tertiary amine salt of glycol succinate (generic). (a) Chemical... as tertiary amine salt of glycol succinate (PMN P-01-595) is subject to reporting under this...

  12. 40 CFR 721.10090 - Tertiary amine salt of glycol succinate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Tertiary amine salt of glycol... Specific Chemical Substances § 721.10090 Tertiary amine salt of glycol succinate (generic). (a) Chemical... as tertiary amine salt of glycol succinate (PMN P-01-595) is subject to reporting under this...

  13. 40 CFR 721.10090 - Tertiary amine salt of glycol succinate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Tertiary amine salt of glycol... Specific Chemical Substances § 721.10090 Tertiary amine salt of glycol succinate (generic). (a) Chemical... as tertiary amine salt of glycol succinate (PMN P-01-595) is subject to reporting under this...

  14. The Petasis Reaction: Microscale Synthesis of a Tertiary Amine Antifungal Analog

    ERIC Educational Resources Information Center

    Koroluk, Katherine J.; Jackson, Derek A.; Dicks, Andrew P.

    2012-01-01

    Students prepare a tertiary amine antifungal analog in an upper-level undergraduate organic laboratory. A microscale Petasis reaction is performed to generate a liquid compound readily characterized via IR and proton NMR spectroscopy. The biological relevance of the product is highlighted, with the tertiary amine scaffold being an important…

  15. Formation Mechanism of NDMA from Ranitidine, Trimethylamine, and Other Tertiary Amines during Chloramination: A Computational Study

    PubMed Central

    2015-01-01

    Chloramination of drinking waters has been associated with N-nitrosodimethylamine (NDMA) formation as a disinfection byproduct. NDMA is classified as a probable carcinogen and thus its formation during chloramination has recently become the focus of considerable research interest. In this study, the formation mechanisms of NDMA from ranitidine and trimethylamine (TMA), as models of tertiary amines, during chloramination were investigated by using density functional theory (DFT). A new four-step formation pathway of NDMA was proposed involving nucleophilic substitution by chloramine, oxidation, and dehydration followed by nitrosation. The results suggested that nitrosation reaction is the rate-limiting step and determines the NDMA yield for tertiary amines. When 45 other tertiary amines were examined, the proposed mechanism was found to be more applicable to aromatic tertiary amines, and there may be still some additional factors or pathways that need to be considered for aliphatic tertiary amines. The heterolytic ONN(Me)2–R+ bond dissociation energy to release NDMA and carbocation R+ was found to be a criterion for evaluating the reactivity of aromatic tertiary amines. A structure–activity study indicates that tertiary amines with benzyl, aromatic heterocyclic ring, and diene-substituted methenyl adjacent to the DMA moiety are potentially significant NDMA precursors. The findings of this study are helpful for understanding NDMA formation mechanism and predicting NDMA yield of a precursor. PMID:24968236

  16. Tertiary-amine-containing thermo- and pH-sensitive hydrophilic ABA triblock copolymers: effect of different tertiary amines on thermally induced sol-gel transitions.

    PubMed

    Henn, Daniel M; Wright, Roger A E; Woodcock, Jeremiah W; Hu, Bin; Zhao, Bin

    2014-03-11

    This Article reports on the synthesis of a series of well-defined, tertiary-amine-containing ABA triblock copolymers, composed of a poly(ethylene oxide) (PEO) central block and thermo- and pH-sensitive outer blocks, and the study of the effect of different tertiary amines on thermally induced sol-gel transition temperatures (T(sol-gel)) of their 10 wt % aqueous solutions. The doubly responsive ABA triblock copolymers were prepared from a difunctional PEO macroinitiator by atom transfer radical polymerization of methoxydi(ethylene glycol) methacrylate and ethoxydi(ethylene glycol) methacrylate at a feed molar ratio of 30:70 with ∼5 mol % of either N,N-diethylaminoethyl methacrylate (DEAEMA), N,N-diisopropylaminoethyl methacrylate, or N,N-di(n-butyl)aminoethyl methacrylate. The chain lengths of thermosensitive outer blocks and the molar contents of tertiary amines were very similar for all copolymers. Using rheological measurements, we determined the pH dependences of T(sol-gel) of 10 wt % aqueous solutions of these copolymers in a phosphate buffer. The T(sol-gel) versus pH curves of all polymers exhibited a sigmoidal shape. The T(sol-gel) increased with decreasing pH; the changes were small on both high and low pH sides. At a specific pH, the T(sol-gel) decreased with increasing the hydrophobicity of the tertiary amine, and upon decreasing pH the onset pH value for the T(sol-gel) to begin to increase noticeably was lower for the more hydrophobic tertiary amine-containing copolymer. In addition, we studied the effect of different tertiary amines on the release behavior of FITC-dextran from 10 wt % micellar gels in an acidic medium at 37 and 27 °C. The release profiles for three studied hydrogels at 37 °C were essentially the same, suggesting that the release was dominated by the diffusion of FITC-dextran. At 27 °C, the release was significantly faster for the DEAEMA-containing copolymer, indicating that both diffusion and gel dissolution contributed to the

  17. Mechanisms of action of cephalosporin 3'-quinolone esters, carbamates, and tertiary amines in Escherichia coli.

    PubMed Central

    Georgopapadakou, N H; Bertasso, A

    1993-01-01

    Cephalosporin 3'-quinolone esters, carbamates, and tertiary amines are potent antibiotics whose antibacterial activities reflect the action of both the beta-lactam and the quinolone components. The biological properties of representative compounds from each class were compared in Escherichia coli. All compounds bound to the essential PBP 3, inhibited DNA gyrase, and caused filamentation in growing cells. To distinguish between cephalosporin- and quinolone-induced filaments, nucleoid segregation was also examined, as quinolones disrupt nucleoid segregation while the beta-lactams do not (N. H. Georgopapadakou and A. Bertasso, Antimicrob. Agents Chemother. 35:2645-2648, 1991). The cephalosporin quinolone esters Ro 23-9424 and Ro 24-6392, at concentrations causing filamentation in E. coli ATCC 25922, did not affect nucleoid segregation after 1 h of incubation (cephalosporin response) but did not affect it after 2 h (quinolone response), indicating the release of free quinolone. Accordingly, only the quinolone response was produced in a strain possessing TEM-3, an expanded-spectrum beta-lactamase. The cephalosporin carbamate Ro 24-4383 and the tertiary amine Ro 24-8138 produced a quinolone response in E. coli ATCC 25922, though they produced a cephalosporin response in a quinolone-resistant strain. Carbamate and tertiary amine linkages are chemically more stable than the ester linkage, and both cephalosporin 3'-quinolone carbamates and tertiary amines are more potent inhibitors of DNA gyrase than are the corresponding esters. The results suggest that, while intact cephalosporin 3'-quinolone esters act as cephalosporins, carbamates and amines may possess both cephalosporin and quinolone activity in the intact molecule. Images PMID:8384817

  18. Structure-Function Relationships of a Tertiary Amine-Based Polycarboxybetaine.

    PubMed

    Lee, Chen-Jung; Wu, Haiyan; Tang, Qiong; Cao, Bin; Wang, Huifeng; Cong, Hongbo; Zhe, Jiang; Xu, Fujian; Cheng, Gang

    2015-09-15

    Zwitterionic polycarboxybetaine (PCB) materials have attracted noticeable interest for biomedical applications, such as wound healing/tissue engineering, medical implants, and biosensors, due to their excellent antifouling properties and design flexibility. Antifouling materials with buffering capability are particularly useful for many biomedical applications. In this work, an integrated zwitterionic polymeric material, poly(2-((2-hydroxyethyl)(2-methacrylamidoethyl)ammonio)acetate) (PCBMAA-1T), was synthesized to carry desired properties (antifouling, switchability and buffering capability). A tertiary amine was used to replace quaternary ammonium as the cation to endow the materials with buffering capability under neutral pH. Through this study, a better understanding on the structure-property relationship of zwitterionic materials was obtained. The tertiary amine cation does not compromise antifouling properties of zwitterionic materials. The amount of adsorbed proteins on PCBMAA-1T polymer brushes is less than 0.8 ng/cm(2) for fibrinogen and 0.3 ng/cm(2) (detection limit of the surface plasmon resonance sensor) for both undiluted blood plasma and serum. It is found that the tertiary amine is favorable to obtain good lactone ring stability in switchable PCB materials. Titration study showed that PCBMAA-1T could resist pH changes under both acidic (pH 1-3) and neutral/basic (pH 7-9) conditions. To the best of our knowledge, such an all-in-one material has not been reported. We believe this material might be potentially used for a variety of applications, including tissue engineering, chronic wound healing and medical device coating.

  19. Kinetic resolution of acids in acylation reactions in the presence of chiral tertiary amines

    SciTech Connect

    Potapov, V.M.; Dem'yanovich, V.M.; Khlebnikov, V.A.

    1988-07-10

    Asymmetric synthesis has now become an important method for the production of optically active compounds, and its most attractive form is asymmetric catalysis. This work was devoted to an investigation into asymmetric catalysis with chiral tertiary amines in acylation reactions. During the acylation of alcohols and amines by the action of racemic 2-phenylpropionic and 2-methyl-3-phenylpropionic acids in the presence of S-nicotine the initial acids are resolved kinetically. The (R)-2-phenylpropionic acid obtained in this way had an optical purity of 0.5-1.5%.

  20. A Highly Active System for the Metal-Free Aerobic Photocyanation of Tertiary Amines with Visible Light: Application to the Synthesis of Tetraponerines and Crispine A.

    PubMed

    Orejarena Pacheco, Julio Cesar; Lipp, Alexander; Nauth, Alexander M; Acke, Fabian; Dietz, Jule-Philipp; Opatz, Till

    2016-04-01

    A highly efficient metal-free catalytic system for the aerobic photocyanation of tertiary amines with visible light is reported. The use of air as terminal oxidant offers an improved safety profile compared with pure oxygen, the used compact fluorescent lamp (CFL) light sources are highly economical, and no halogenated solvents are required. This system not only proves to be effective for a wide variety of trialkylamines, pharmaceuticals, and alkaloids but remarkably also allows the lowest catalyst loading (0.00001 mol% or 0.1 ppm) ever reported for an organic dye. Bruylants reactions and C-alkylation/decyanations were performed on the obtained α-aminonitriles to demonstrate the postfunctionalization of complex molecules. The catalytic system is furthermore applied in the short and effective syntheses of the alkaloids (±)-crispine A and the tetraponerines T7 and T8.

  1. A Highly Active System for the Metal-Free Aerobic Photocyanation of Tertiary Amines with Visible Light: Application to the Synthesis of Tetraponerines and Crispine A.

    PubMed

    Orejarena Pacheco, Julio Cesar; Lipp, Alexander; Nauth, Alexander M; Acke, Fabian; Dietz, Jule-Philipp; Opatz, Till

    2016-04-01

    A highly efficient metal-free catalytic system for the aerobic photocyanation of tertiary amines with visible light is reported. The use of air as terminal oxidant offers an improved safety profile compared with pure oxygen, the used compact fluorescent lamp (CFL) light sources are highly economical, and no halogenated solvents are required. This system not only proves to be effective for a wide variety of trialkylamines, pharmaceuticals, and alkaloids but remarkably also allows the lowest catalyst loading (0.00001 mol% or 0.1 ppm) ever reported for an organic dye. Bruylants reactions and C-alkylation/decyanations were performed on the obtained α-aminonitriles to demonstrate the postfunctionalization of complex molecules. The catalytic system is furthermore applied in the short and effective syntheses of the alkaloids (±)-crispine A and the tetraponerines T7 and T8. PMID:26929114

  2. Investigating the Effects of Block versus Statistical Glycopolycations Containing Primary and Tertiary Amines for Plasmid DNA Delivery

    PubMed Central

    2015-01-01

    Polymer composition and morphology can affect the way polymers interact with biomolecules, cell membranes, and intracellular components. Herein, diblock, triblock, and statistical polymers that varied in charge center type (primary and/or tertiary amines) were synthesized to elucidate the role of polymer composition on plasmid DNA complexation, delivery, and cellular toxicity of the resultant polyplexes. The polymers were synthesized via RAFT polymerization and were composed of a carbohydrate moiety, 2-deoxy-2-methacrylamido glucopyranose (MAG), a primary amine group, N-(2-aminoethyl) methacrylamide (AEMA), and/or a tertiary amine moiety, N,N-(2-dimethylamino)ethyl methacrylamide (DMAEMA). The lengths of both the carbohydrate and cationic blocks were kept constant while the primary amine to tertiary amine ratio was varied within the polymers. The polymers were characterized via nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC), and the polyplex formulations with pDNA were characterized in various media using dynamic light scattering (DLS). Polyplexes formed with the block copolymers were found to be more colloidally stable than statistical copolymers with similar composition, which rapidly aggregated to micrometer sized particles. Also, polymers composed of a higher primary amine content were more colloidally stable than polymers consisting of the tertiary amine charge centers. Plasmid DNA internalization, transgene expression, and toxicity were examined with each polymer. As the amount of tertiary amine in the triblock copolymers increased, both gene expression and toxicity were found to increase. Moreover, it was found that increasing the content of tertiary amines imparted higher membrane disruption/destabilization. While both block and statistical copolymers had high transfection efficiencies, some of the statistical systems exhibited both higher transfection and toxicity than the analogous block polymers, potentially due to the lack of a

  3. Investigating the effects of block versus statistical glycopolycations containing primary and tertiary amines for plasmid DNA delivery.

    PubMed

    Sprouse, Dustin; Reineke, Theresa M

    2014-07-14

    Polymer composition and morphology can affect the way polymers interact with biomolecules, cell membranes, and intracellular components. Herein, diblock, triblock, and statistical polymers that varied in charge center type (primary and/or tertiary amines) were synthesized to elucidate the role of polymer composition on plasmid DNA complexation, delivery, and cellular toxicity of the resultant polyplexes. The polymers were synthesized via RAFT polymerization and were composed of a carbohydrate moiety, 2-deoxy-2-methacrylamido glucopyranose (MAG), a primary amine group, N-(2-aminoethyl) methacrylamide (AEMA), and/or a tertiary amine moiety, N,N-(2-dimethylamino)ethyl methacrylamide (DMAEMA). The lengths of both the carbohydrate and cationic blocks were kept constant while the primary amine to tertiary amine ratio was varied within the polymers. The polymers were characterized via nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC), and the polyplex formulations with pDNA were characterized in various media using dynamic light scattering (DLS). Polyplexes formed with the block copolymers were found to be more colloidally stable than statistical copolymers with similar composition, which rapidly aggregated to micrometer sized particles. Also, polymers composed of a higher primary amine content were more colloidally stable than polymers consisting of the tertiary amine charge centers. Plasmid DNA internalization, transgene expression, and toxicity were examined with each polymer. As the amount of tertiary amine in the triblock copolymers increased, both gene expression and toxicity were found to increase. Moreover, it was found that increasing the content of tertiary amines imparted higher membrane disruption/destabilization. While both block and statistical copolymers had high transfection efficiencies, some of the statistical systems exhibited both higher transfection and toxicity than the analogous block polymers, potentially due to the lack of a

  4. Palladium-Catalyzed Oxidative N-Dealkylation/Carbonylation of Tertiary Amines with Alkynes to α,β-Alkynylamides.

    PubMed

    Mane, Rajendra S; Bhanage, Bhalchandra M

    2016-06-17

    The first highly effective Pd/C-catalyzed oxidative N-dealkylation/carbonylation of various aliphatic as well as cyclic tertiary amines with alkynes has been described. The selective sp(3) C-N bond activation of tertiary amines at the less steric side using O2 as a sole oxidant and a plausible reaction pathway for the reaction are discussed. The general and operationally simple methodology provides an alternative for the synthesis of a wide range of alk-2-ynamide derivatives under mild conditions. The present protocol is ecofriendly and practical, and it shows significant recyclability. PMID:27182623

  5. Pd/C-Catalyzed Aminocarbonylation of Aryl Iodides via Oxidative C-N Bond Activation of Tertiary Amines to Tertiary Amides.

    PubMed

    Mane, Rajendra S; Bhanage, Bhalchandra M

    2016-02-01

    This work reports oxidative N-dealkylation/carbonylation of tertiary amines to tertiary amides by using molecular oxygen as a sole oxidant using a Pd/C catalyst. This protocol is free from ligands, additives, bases, and cocatalysts. Different tertiary amines as well as aryl iodides have been examined for this transformation, providing desired products in good to excellent yield. PMID:26756705

  6. Tertiary amines related to brompheniramine: preferred conformations for N-oxygenation by the hog liver flavin-containing monooxygenase.

    PubMed

    Cashman, J R; Celestial, J R; Leach, A; Newdoll, J; Park, S B

    1993-08-01

    The metabolism of racemic, (D)- and (L)-brompheniramine, a widely used antihistamine, was studied with microsomes and with highly purified flavin-containing monooxygenase (FMO) from hog liver. In addition, a number of other similar tertiary amines were evaluated as substrates for FMO activity from hog liver and the kinetic constants obtained were compared with brompheniramine. Although some N-demethylation was observed, the major metabolite of brompheniramine and the other tertiary amines examined in hog liver microsomes was the metabolite containing an aliphatic nitrogen N-oxide. Brompheniramine was extensively N-oxygenated by the highly purified FMO from hog liver. N-Oxygenation of brompheniramine in both microsomes and with highly purified FMO from hog liver was enantioselective. The Km for N-oxygenation of (D)-brompheniramine was markedly lower than the Km for (L)-brompheniramine. (E)- and (Z)-zimeldine are less conformationally flexible model compounds of brompheniramine, and these compounds were also examined and were found to be stereoselectively N-oxygenated by the highly purified FMO from hog liver. The similarities and differences in Km and Vmax values were evaluated in terms of possible conformations of the substrates determined by SYBYL molecular mechanics calculations. Distance map data indicated that FMO preferentially accommodated selected conformations of tertiary amines. Thus, (D)-brompheniramine and (Z)-zimeldine presumably have the aliphatic tertiary amine nitrogen atom and aromatic ring center at a defined distance and geometry and were more efficiently N-oxygenated than their respective isomers. PMID:8415393

  7. Tertiary amines related to brompheniramine: preferred conformations for N-oxygenation by the hog liver flavin-containing monooxygenase.

    PubMed

    Cashman, J R; Celestial, J R; Leach, A; Newdoll, J; Park, S B

    1993-08-01

    The metabolism of racemic, (D)- and (L)-brompheniramine, a widely used antihistamine, was studied with microsomes and with highly purified flavin-containing monooxygenase (FMO) from hog liver. In addition, a number of other similar tertiary amines were evaluated as substrates for FMO activity from hog liver and the kinetic constants obtained were compared with brompheniramine. Although some N-demethylation was observed, the major metabolite of brompheniramine and the other tertiary amines examined in hog liver microsomes was the metabolite containing an aliphatic nitrogen N-oxide. Brompheniramine was extensively N-oxygenated by the highly purified FMO from hog liver. N-Oxygenation of brompheniramine in both microsomes and with highly purified FMO from hog liver was enantioselective. The Km for N-oxygenation of (D)-brompheniramine was markedly lower than the Km for (L)-brompheniramine. (E)- and (Z)-zimeldine are less conformationally flexible model compounds of brompheniramine, and these compounds were also examined and were found to be stereoselectively N-oxygenated by the highly purified FMO from hog liver. The similarities and differences in Km and Vmax values were evaluated in terms of possible conformations of the substrates determined by SYBYL molecular mechanics calculations. Distance map data indicated that FMO preferentially accommodated selected conformations of tertiary amines. Thus, (D)-brompheniramine and (Z)-zimeldine presumably have the aliphatic tertiary amine nitrogen atom and aromatic ring center at a defined distance and geometry and were more efficiently N-oxygenated than their respective isomers.

  8. Brønsted acid cocatalysis in photocatalytic intramolecular coupling of tertiary amines: efficient synthesis of 2-arylindols.

    PubMed

    Yuan, Xiaoqian; Wu, Xinxin; Dong, Shupeng; Wu, Guibing; Ye, Jinxing

    2016-08-21

    We report herein a highly efficient intramolecular coupling reaction of tertiary amines and ketones (α,β-unsaturated ketones) by using a Brønsted acid as a cocatalyst, affording 2-arylindols in good to excellent yields (up to 92%) under visible light irradiation at room temperature. PMID:27431277

  9. Upregulation of BMSCs Osteogenesis by Positively-Charged Tertiary Amines on Polymeric Implants via Charge/iNOS Signaling Pathway

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Liu, Na; Shi, Haigang; Liu, Jun; Shi, Lianxin; Zhang, Bo; Wang, Huaiyu; Ji, Junhui; Chu, Paul K.

    2015-03-01

    Positively-charged surfaces on implants have a similar potential to upregulate osteogenesis of bone marrow-derived mesenchymal stem cells (BMSCs) as electromagnetic therapy approved for bone regeneration. Generally, their osteogenesis functions are generally considered to stem from the charge-induced adhesion of extracellular matrix (ECM) proteins without exploring the underlying surface charge/cell signaling molecule pathways. Herein, a positively-charged surface with controllable tertiary amines is produced on a polymer implant by plasma surface modification. In addition to inhibiting the TNF-α expression, the positively-charged surface with tertiary amines exhibits excellent cytocompatibility as well as remarkably upregulated osteogenesis-related gene/protein expressions and calcification of the contacted BMSCs. Stimulated by the charged surface, these BMSCs display high iNOS expressions among the three NOS isoforms. Meanwhile, downregulation of the iNOS by L-Can or siRNA inhibit osteogenic differentiation in the BMSCs. These findings suggest that a positively-charged surface with tertiary amines induces osteogenesis of BMSCs via the surface charge/iNOS signaling pathway in addition to elevated ECM protein adhesion. Therefore, creating a positively-charged surface with tertiary amines is a promising approach to promote osseointegration with bone tissues.

  10. PROCESS FOR EXTRACTING NEPTUNIUM AND PLUTONIUM FROM NITRIC ACID SOLUTIONS OF SAME CONTAINING URANYL NITRATE WITH A TERTIARY AMINE

    DOEpatents

    Sheppard, J.C.

    1962-07-31

    A process of selectively extracting plutonium nitrate and neptunium nitrate with an organic solution of a tertiary amine, away from uranyl nitrate present in an aqueous solution in a maximum concentration of 1M is described. The nitric acid concentration is adjusted to about 4M and nitrous acid is added prior to extraction. (AEC)

  11. Upregulation of BMSCs Osteogenesis by Positively-Charged Tertiary Amines on Polymeric Implants via Charge/iNOS Signaling Pathway

    PubMed Central

    Zhang, Wei; Liu, Na; Shi, Haigang; Liu, Jun; Shi, Lianxin; Zhang, Bo; Wang, Huaiyu; Ji, Junhui; Chu, Paul K.

    2015-01-01

    Positively-charged surfaces on implants have a similar potential to upregulate osteogenesis of bone marrow-derived mesenchymal stem cells (BMSCs) as electromagnetic therapy approved for bone regeneration. Generally, their osteogenesis functions are generally considered to stem from the charge-induced adhesion of extracellular matrix (ECM) proteins without exploring the underlying surface charge/cell signaling molecule pathways. Herein, a positively-charged surface with controllable tertiary amines is produced on a polymer implant by plasma surface modification. In addition to inhibiting the TNF-α expression, the positively-charged surface with tertiary amines exhibits excellent cytocompatibility as well as remarkably upregulated osteogenesis-related gene/protein expressions and calcification of the contacted BMSCs. Stimulated by the charged surface, these BMSCs display high iNOS expressions among the three NOS isoforms. Meanwhile, downregulation of the iNOS by L-Can or siRNA inhibit osteogenic differentiation in the BMSCs. These findings suggest that a positively-charged surface with tertiary amines induces osteogenesis of BMSCs via the surface charge/iNOS signaling pathway in addition to elevated ECM protein adhesion. Therefore, creating a positively-charged surface with tertiary amines is a promising approach to promote osseointegration with bone tissues. PMID:25791957

  12. CO2-responsive aliphatic tertiary amine-modified alginate and its application as a switchable surfactant.

    PubMed

    Yang, Jisheng; Dong, Hongbiao

    2016-11-20

    A new kind of hexyl diethyl tertiary amine-grafted amphiphilic alginate derivative (HDEA-Alg) was synthesized from (6-bromo-hexyl)-diethyl-amine (BHDEA) and sodium alginate (NaAlg) through esterification. The structure of HDEA-Alg was confirmed by FT-IR and NMR spectroscopies. The grafting ratio was calculated according elemental analysis and thermodynamic property was analyzed by TG. The CO2/N2-responsive performance of HDEA-Alg in aqueous solution was demonstrated by surface tension and conductivity measurements. Stable emulsions of liquid paraffin were easily prepared in the presence of the HDEA-Alg. These emulsions can be de-emulsified by bubbling CO2 through the emulsions at 5°C for 30min, resulting in complete oil/water phase separations. They can be re-emulsified by bubbling N2 through the solutions at 50°C for 30min with the aid of homogenization. PMID:27561465

  13. Regulation of carbon partitioning into carotenes by MPTA, a substituted tertiary amine

    SciTech Connect

    Madhavan, S.; Rosenfield, C.L.; Benedict, C.R.

    1986-04-01

    In mature citrus fruits, synthesis and turnover of carotenes appears to be low. Treatment of lemon pieces with the substituted tertiary amine, 2-(4-methylphenoxyl)triethylamine, MPTA, induces the synthesis of carotenes. Exposure of tissue slices (lemon flavedo) to MPTA for 72 hrs results in the production of 29.6 ..mu..g gfrwt/sup -1/ lycopene whereas control slices showed only trace amounts of lycopene. An identical incorporation of /sup 14/C-glucose into sugars, amino acids and organic acids, in both treated and control tissue slices indicates the non-disturbance of fruit respiration by MPTA treatment. Incorporation of /sup 14/C-glucose into carotenes is negligible in mature citrus fruits, but in MPTA treated tissue slices there is a pronounced incorporation of /sup 14/C-glucose into carotenes. MPTA treatment induces the synthesis of carotene enzymes, thus effecting an increased partitioning of glucose into the MVA pathway for carotene synthesis.

  14. Thermodynamic and Experimental Study of the Energetic Cost Involved in the Capture of Carbon Dioxide by Aqueous Mixtures of Commonly Used Primary and Tertiary Amines.

    PubMed

    Arcis, Hugues; Coulier, Yohann; Coxam, Jean-Yves

    2016-01-01

    The capture of carbon dioxide with chemical solvents is one solution to mitigate greenhouse gas emissions from anthropogenic sources and thus tackle climate change. Recent research has been focused on optimizing new kinds of advanced absorbents including aqueous amine blends, but critical downsides such as the large energetic cost involved with the industrial process remain. To address this issue, a better understanding of the energetic interactions existing in solution is necessary. In this paper, we report direct experimental measurements of the energy cost involved in the solvation of CO2 in two aqueous amine blends at different temperatures. The chemical solvents were designed as aqueous mixtures of commonly used primary and tertiary amines to study the influence of the different chemical properties inferred by the amine class. We have also applied a thermodynamic model to represent the energetic effects that take place in solution during CO2 dissolution in these mixtures, where all parameters were taken from previous studies focused on single amine absorbents. The noteworthy agreement observed with the reported experimental heats of absorption and with literature vapor liquid equilibrium properties confirmed the relevance of the underlying molecular mechanisms considered in our model, and suggest that this model would prove useful to investigate CO2 dissolution in other amine blends.

  15. Difluoromethyltrialkylammonium salts--their expeditious synthesis from chlorodifluoromethane and tertiary amines in the presence of concentrated aqueous sodium hydroxide. The catalytic process.

    PubMed

    Nawrot, Ewelina; Joñczyk, Andrzej

    2007-12-21

    We found that difluorocarbene generated from chlorodifluoromethane with 50% aqueous sodium hydroxide reacts with lipophilic tertiary amines 1a-g giving difluoromethyltrialkylammonium chlorides 2a-g in high yields. Similarly, difluoromethyltrialkylammonium iodides 3h-l, nitrates 4h-k, or isothiocyanates 5i,j were synthesized from hydrophilic tertiary amines 1h-l and the corresponding sodium or potassium salts. The process is catalytic with respect to the base used.

  16. (E)-α,β-unsaturated amides from tertiary amines, olefins and CO via Pd/Cu-catalyzed aerobic oxidative N-dealkylation.

    PubMed

    Shi, Renyi; Zhang, Hua; Lu, Lijun; Gan, Pei; Sha, Yuchen; Zhang, Heng; Liu, Qiang; Beller, Matthias; Lei, Aiwen

    2015-02-21

    A novel Pd/Cu-catalyzed chemoselective aerobic oxidative N-dealkylation/carbonylation reaction has been developed. Tertiary amines are utilized as a "reservoir" of "active" secondary amines in this transformation, which inhibits the formation of undesired by-products and the deactivation of the catalysts. This protocol allows for an efficient and straightforward construction of synthetically useful and bioactive (E)-α,β-unsaturated amide derivatives from easily available tertiary amines, olefins and CO. PMID:25610923

  17. Composition and properties of porous blend membranes containing tertiary amine based amphiphilic copolymers with different sequence structures.

    PubMed

    Yao, Zhikan; Cui, Yue; Zheng, Ke; Zhu, Baoku; Zhu, Liping

    2015-01-01

    Four tertiary amine based amphiphilic copolymers with similar composition but different sequence structures in terms of diblock (Poly(dimethylamino-2-ethyl methacrylate-b-methyl methacrylate) (P(MMA-b-DMAEMA))), triblock (P(DMAEMA-b-MMA-b-DMAEMA)), four-armed diblock (P(MMA-b-DMAEMA)4) and random (P(MMA-r-DMAEMA)) were synthesized and used for fabricating functional porous membranes by blending method. The retention ratios and surface enrichment ratios of the copolymers in blend membranes were determined by hydrogen nuclear magnetic resonance ((1)H-NMR) and X-ray photoelectron spectroscopy (XPS). The composition of the formed membranes was investigated and the durability was experimentally tested. The hydrophilicity of the membranes was evaluated by water contact angle measurement. The performance of membranes under different conditions including water fluxes at different pH and various ionic strength, the adsorption capabilities for Cr(VI) and negatively charged dye sunset yellow at different pH was studied. The results show that tertiary amine based amphiphilic copolymers with block and multi-armed sequence structures enable the blend membranes with higher copolymer retention ratios, more surface tertiary amine groups contents and better composition stability as well as more sensitive to the variation of pH, ionic strength, higher equilibrium anions, and negatively charged dyes uptakes.

  18. Carbon Dioxide Sequestration by Using a Model Carbonic Anhydrase Complex in Tertiary Amine Medium.

    PubMed

    Sivanesan, Dharmalingam; Choi, Youngju; Lee, Jiyeon; Youn, Min Hye; Park, Ki Tae; Grace, Andrew Nirmala; Kim, Hak-Joo; Jeong, Soon Kwan

    2015-12-01

    Globally, the elevation of carbon dioxide (CO2 ) levels due to the anthropogenic effect poses a serious threat to the ecosystem. Hence, it is important to control and/or mitigate the level of CO2 in the atmosphere, which necessitates novel tools. Herein, it is proposed to improve CO2 sequestration by using model complexes based on the enzyme carbonic anhydrase (CA) in aqueous tertiary amine medium. The effect of substituents on the model CA model complexes on CO2 absorption and desorption was determined by using a stopped-flow spectrophotometer to follow pH changes through coupling to pH indicator and a continuous stirred-tank reactor (CSTR). The CO2 hydration rate constants were determined under basic conditions and compound 6, which contained a hydrophilic group, showed the highest absorption or hydration levels of CO2 (2.860×10(3)  L mol(-1)  s(-1) ). In addition, CSTR results for the absorption and desorption of CO2 suggest that simple model CA complexes could be used in post-combustion processing.

  19. Enhancing polysaccharide-mediated delivery of nucleic acids through functionalization with secondary and tertiary amines.

    PubMed

    Ghosn, Bilal; Kasturi, Sudhir Pai; Roy, Krishnendu

    2008-01-01

    Chitosan is a polysaccharide that has generated significant interest as a non-viral gene delivery vehicle due to its cationic and biocompatible characteristics. However, transfection efficiency of chitosan is significantly lower compared to other cationic gene delivery agents, e.g. polyethyleneimine (PEI), dendrimers or cationic lipids. This is primarily attributed to its minimal solubility and low buffering capacity at physiological pH leading to poor endosomal escape of the gene carrier and inefficient cytoplasmic decoupling of the complexed nucleic acid. Here we have developed an imidazole acetic acid (IAA)-modified chitosan to introduce secondary and tertiary amines to the polymer in order to improve its endosomal buffering and solubility. The modified polymer was characterized by ninhydrin and (1)H NMR assays for degree of modification, while buffering and solubility were analyzed by acid titration. Nanocomplex formation, studied at various polymer-nucleic acid ratios, showed an increase in particle zeta potential for chitosan-IAA, as well as an increase in the effective diameter. Up to 100-fold increase in transfection efficiency of pDNA was seen for chitosan-IAA as compared to native chitosan, nearly matching that of PEI. In addition, transfection of siRNA by the modified polymers showed efficient gene knockdown equivalent to commercially available siPORT Amines. Collectively, these results demonstrate the potential of the imidazole-grafted chitosan as a biocompatible and effective delivery vehicle for both pDNA and siRNA.

  20. Probing the role of secondary versus tertiary amine donor ligands for indium catalysts in lactide polymerization.

    PubMed

    Osten, Kimberly M; Aluthge, Dinesh C; Patrick, Brian O; Mehrkhodavandi, Parisa

    2014-09-15

    The role of the central amine donor in a previously reported dinuclear indium catalyst, [N(Me2)N(H)O)InCl]2(μ-Cl)(μ-OEt) (1), for the polymerization of lactide was investigated through experimental methods. The solid state structural data of a series of dimeric complexes related to 1, including the previously reported bromide derivative [(N(Me2)N(H)O)InBr](μ-Br)(μ-OEt) (2) and the newly synthesized methylated derivative [(N(Me2)N(Me)O)InCl]2(μ-Cl)(μ-OEt) (6), showed that weak hydrogen bonding may be present within some of these complexes in the solid state. The polymerization of rac-lactide with 2, 6, and a related achiral complex [(L(H))InCl]2(μ-Cl)(μ-OEt) (8) synthesized for this study indicates that hydrogen bonding may not influence the reactivity of these compounds. The nature of the central amine donor may play a role in tuning the reactivity of these types of catalysts. Catalysts with central secondary amine donors, such as complexes 1, 2, and 8, are 2 orders of magnitude more reactive than those with central tertiary amine donors, such as complex 6.

  1. beta-Lactamase hydrolysis of cephalosporin 3'-quinolone esters, carbamates, and tertiary amines.

    PubMed Central

    Georgopapadakou, N H; McCaffrey, C

    1994-01-01

    The beta-lactam hydrolysis of five cephalosporin 3'-quinolones (dual-action cephalosporins) by three gram-negative beta-lactamases was examined. The dual-action cephalosporins tested were the ester Ro 23-9424; the carbamates Ro 25-2016, Ro 25-4095, and Ro 25-4835; and the tertiary amine Ro 25-0534. Also tested were cephalosporins with similar side chains (cefotaxime, desacetylcefotaxime, cephalothin, cephacetrile, and Ro 09-1227 [SR 0124]) and standard beta-lactams (penicillin G, cephaloridine). The beta-lactamases used were the plasmid-mediated TEM-1 and TEM-3 enzymes and the chromosomal AmpC. The cephacetrile-related compounds Ro 25-4095 and Ro 25-4835 were hydrolyzed by all three beta-lactamases with catalytic efficiencies (relative to penicillin G) ranging from approximately 5 (TEM-1, AmpC) to approximately 25 (TEM-3). The cephalothin-related Ro 25-2016 was also hydrolyzed by all three beta-lactamases, particularly the AmpC enzyme (relative catalytic efficiency, 110). The cefotaxime-related compounds Ro 25-0534 and Ro 23-9424 were hydrolyzed to any significant extent only by the TEM-3 enzyme (relative catalytic efficiencies, 1.2 and 4.7, respectively. PMID:8067776

  2. Improvement of initial adhesion to aluminum of insulating glass polyurethane sealants using a tertiary amine based curing system

    SciTech Connect

    Hubin-Eschger, P.J.

    1996-12-31

    Hydroxylated polybutadiene based insulated glass sealants are well known to have a very low moisture vapor transmission rate and an excellent adhesion to glass and aluminum. Since the beginning of their industrial development, the best and most known and effective curing system for these sealants has been an organomercuric ester based catalyst. The current and future pressure regarding ecological and toxicological issues will make this type of product increasingly difficult to use. This paper presents the results of work to develop other catalytic systems, which were obtained with the tertiary amine dimethylbenzylamine. The final improvement of initial adhesion to aluminum is obtained with the use of phenolic derivatives of coumarone indene.

  3. Nitromethane with IBX/TBAF as a nitrosating agent: synthesis of nitrosamines from secondary or tertiary amines under mild conditions.

    PubMed

    Potturi, Hima K; Gurung, Ras K; Hou, Yuqing

    2012-01-01

    Aliphatic or aromatic N,N-disubstituted nitrosamine was generated in fair to excellent yield from the reaction of a secondary or tertiary amine with o-iodoxybenzoic acid (IBX) or o-iodosylbenzoic acid (IBA)/R(4)NX (X = halide) and nitromethane. The product yield was strongly influenced by both the halide of R(4)NX and iodanes. IBX gave a higher yield than IBA, while the halides follow F(-) > Cl(-) > Br(-) ∼ I(-). Nitrous acid formed in situ from nitromethane and IBX (or IBA)/halides is likely responsible for the observed reaction.

  4. Energy-efficient green catalysis: supported gold nanoparticle-catalyzed aminolysis of esters with inert tertiary amines by C-O and C-N bond activations.

    PubMed

    Bao, Yong-Sheng; Baiyin, Menghe; Agula, Bao; Jia, Meilin; Zhaorigetu, Bao

    2014-07-18

    Catalyzed by supported gold nanoparticles, an aminolysis reaction between various aryl esters and inert tertiary amines by C-O and C-N bond activations has been developed for the selective synthesis of tertiary amides. Comparison studies indicated that the gold nanoparticles could perform energy-efficient green catalysis at room temperature, whereas Pd(OAc)2 could not.

  5. Squaramide-tertiary amine catalyzed asymmetric cascade sulfa-Michael/Michael addition via dynamic kinetic resolution: access to highly functionalized chromans with three contiguous stereocenters.

    PubMed

    Yang, Wen; Yang, Yi; Du, Da-Ming

    2013-03-15

    An efficient asymmetric cascade sulfa-Michael/Michael addition reaction catalyzed by a chiral bifunctional squaramide-tertiary amine catalyst has been developed. This organocatalytic cascade reaction provides easy access to highly functionalized chromans with three contiguous stereocenters, including one quaternary center. In addition, a novel cascade sulfa Michael/retro-sulfa-Michael/sulfa-Michael/Michael reaction process, involving dynamic kinetic resolution, is described.

  6. Bifunctional heterogeneous catalysis of silica-alumina-supported tertiary amines with controlled acid-base interactions for efficient 1,4-addition reactions.

    PubMed

    Motokura, Ken; Tanaka, Satoka; Tada, Mizuki; Iwasawa, Yasuhiro

    2009-10-19

    We report the first tunable bifunctional surface of silica-alumina-supported tertiary amines (SA-NEt(2)) active for catalytic 1,4-addition reactions of nitroalkanes and thiols to electron-deficient alkenes. The 1,4-addition reaction of nitroalkanes to electron-deficient alkenes is one of the most useful carbon-carbon bond-forming reactions and applicable toward a wide range of organic syntheses. The reaction between nitroethane and methyl vinyl ketone scarcely proceeded with either SA or homogeneous amines, and a mixture of SA and amines showed very low catalytic activity. In addition, undesirable side reactions occurred in the case of a strong base like sodium ethoxide employed as a catalytic reagent. Only the present SA-supported amine (SA-NEt(2)) catalyst enabled selective formation of a double-alkylated product without promotions of side reactions such as an intramolecular cyclization reaction. The heterogeneous SA-NEt(2) catalyst was easily recovered from the reaction mixture by simple filtration and reusable with retention of its catalytic activity and selectivity. Furthermore, the SA-NEt(2) catalyst system was applicable to the addition reaction of other nitroalkanes and thiols to various electron-deficient alkenes. The solid-state magic-angle spinning (MAS) NMR spectroscopic analyses, including variable-contact-time (13)C cross-polarization (CP)/MAS NMR spectroscopy, revealed that acid-base interactions between surface acid sites and immobilized amines can be controlled by pretreatment of SA at different temperatures. The catalytic activities for these addition reactions were strongly affected by the surface acid-base interactions.

  7. Highly porous organic polymers bearing tertiary amine group and their exceptionally high CO{sub 2} uptake capacities

    SciTech Connect

    Gomes, Ruth; Bhaumik, Asim

    2015-02-15

    We report a very simple and unique strategy for synthesis of a tertiary amine functionalized high surface area porous organic polymer (POP) PDVTA-1 through the co-polymerization of monomers divinylbenzene (DVB) and triallylamine (TAA) under solvothermal reaction conditions. Two different PDVTA-1 samples have been synthesized by varying the molar ratio of the monomers. The porous polymeric materials have been thoroughly characterized by solid state {sup 13}C CP MAS-NMR, FT-IR and UV–vis spectroscopy, N{sub 2} sorption, HR TEM and FE SEM to understand its chemical environment, nanostructure, bonding, morphology and related surface properties. PDVTA-1 with higher amine content (DVB/TAA=4.0) showed exceptionally high CO{sub 2} uptake capacity of 85.8 wt% (19.5 mmol g{sup −1}) at 273 K and 43.69 wt% (9.93 mmol g{sup −1}) at 298 K under 3 bar pressure, whereas relatively low amine loaded material (DVB/TAA=7.0) shows uptake capacity of 59.2 wt% (13.45 mmol g{sup −1}) at 273 K and 34.36 wt% (7.81 mmol g{sup −1}) at 298 K. Highly porous nanostructure together with very high surface area and basicity at the surface due to the presence of abundant basic tertiary amine N-sites in the framework of PDVTA-1 could be responsible for very high CO{sub 2} adsorption. - Graphical abstract: Exceptionally high CO2 uptake (85.8 wt % at 273 K) has been observed over a high surface area porous organic polymer PDVTA-1 synthesized through copolymerization of divinylbenzene and triallyl amine. - Highlights: • Designing the synthesis of a new N-rich cross-linked porous organic polymer PDVTA-1. • PDVTA-1 showed mesoporosity with very high surface area of 903 m{sup 2} g{sup −1}. • High surface area and presence of basic sites facilitates the CO{sub 2} uptake. • PDVTA-1 showed exceptionally high CO{sub 2} adsorption capacity of 85.8 wt% at 273 K, 3 bar pressure.

  8. Sequential Addition Reaction of Sulfanylmethyllithiums and Grignard Reagents to Thioformamides Leading to the Formation of 2-Phenyl-2-sulfanylethyl Tertiary Amines.

    PubMed

    Murai, Toshiaki; Mutoh, Natsumi

    2016-09-16

    The reaction of sulfanylmethyllithiums generated from benzylsulfanes and n-BuLi with N,N-dimethylthioformamide followed by the addition of Grignard reagents gave 2-phenyl-2-sulfanyl tertiary amines in moderate to good yields. A range of Grignard reagents involving primary alkyl, aryl, vinyl, and alkynyl Grignard reagents were used. Two carbon-carbon bond-forming reactions were achieved through a one-pot reaction. The reaction showed good to high diastereoselectivity, particularly with alkynyl Grignard reagents. PMID:27565031

  9. Oxidation of tertiary amines by cytochrome p450-kinetic isotope effect as a spin-state reactivity probe.

    PubMed

    Li, Chunsen; Wu, Wei; Cho, Kyung-Bin; Shaik, Sason

    2009-08-24

    Two types of tertiary amine oxidation processes, namely, N-dealkylation and N-oxygenation, by compound I (Cpd I) of cytochrome P450 are studied theoretically using hybrid DFT calculations. All the calculations show that both N-dealkylation and N-oxygenation of trimethylamine (TMA) proceed preferentially from the low-spin (LS) state of Cpd I. Indeed, the computed kinetic isotope effects (KIEs) for the rate-controlling hydrogen abstraction step of dealkylation show that only the KIE(LS) fits the experimental datum, whereas the corresponding value for the high-spin (HS) process is much higher. These results second those published before for N,N-dimethylaniline (DMA), and as such, they further confirm the conclusion drawn then that KIEs can be a sensitive probe of spin state reactivity. The ferric-carbinolamine of TMA decomposes most likely in a non-enzymatic reaction since the Fe-O bond dissociation energy (BDE) is negative. The computational results reveal that in the reverse reaction of N-oxygenation, the N-oxide of aromatic amine can serve as a better oxygen donor than that of aliphatic amine to generate Cpd I. This capability of the N-oxo derivatives of aromatic amines to transfer oxygen to the heme, and thereby generate Cpd I, is in good accord with experimental data previously reported. PMID:19322770

  10. Synthesis of a novel tertiary amine containing urethane dimethacrylate monomer (UDMTA) and its application in dental resin.

    PubMed

    Liu, Dongliang; Liu, Fang; He, Jingwei; Lassila, Lippo V J; Vallittu, Pekka K

    2013-06-01

    A novel tertiary amine containing urethane dimethacrylate monomer UDMTA was synthesized with the aim of replacing Bis-GMA as one component of dental restorative materials. The structure of UDMTA was confirmed by FT-IR and (1)H-NMR spectra. UDMTA was incorporated into Bis-GMA/TEGDMA (50 wt%/50 wt%) resin system to replace Bis-GMA partly and totally. Double bond conversion, polymerization volumetric shrinkage, water sorption and solubility, flexural strength and modulus of UDMTA containing resin formulations were studied with neat Bis-GMA/TEGDMA resin formulation as a reference. Results showed that UDMTA could be used as a coinitiator in photocurable dental resin, UDMTA containing resin had higher double bond conversion and lower polymerization shrinkage than that of Bis-GMA/TEGDMA resin, and the UDMTA containing copolymer had higher flexural strength and flexural modulus than Bis-GMA/TEGDMA copolymer. When UDMTA was used to replace more than 25 wt% of Bis-GMA, the obtained copolymer had higher water sorption and solubility. The optimized resin composition is by replacing 25 wt% of Bis-GMA in Bis-GMA/TEGDMA (50/50 by wt%), for the prepared resin had the best comprehensive properties.

  11. Two coordination polymers constructed from a multidentate carboxylic acid ligand with a tertiary amine serve as acid-base catalysts for the synthesis of chloropropene carbonate from CO2 under atmospheric pressure.

    PubMed

    Chen, Chao; Zhang, Jun; Li, Guanghua; Shen, Pan; Jin, Haichao; Zhang, Ning

    2014-10-01

    Two new coordination polymers, [Ni(H2O)(Hpdcd)(H2O)2]·DMF (1) and [Co(H2O)(Hpdcd)(H2O)2]·DMF (2) (H3pdcd = 1-(4-carboxyphenyl)-2,5-dimethyl, 1H-pyrrole-3,4-dicarboxylic acid), which were designed based on a tertiary amine ligand, were synthesized and characterized using multiple spectroscopy techniques, including single-crystal X-ray diffraction. These two 1D linear chains possess the properties of both a Lewis acid and organic base, which was confirmed by temperature programmed desorption of ammonia and on-line mass spectrometry (NH3-TPD-MS), and selective sorption for carbon dioxide. Due to their acid-base properties, the compounds exhibited high catalytic activity, in the absence of co-catalysts, for solvent-free synthesis of chloropropene carbonate from CO2 and epichlorohydrin under atmospheric CO2 pressure. The yields of chloropropene carbonate were 88% and 87% for 1 and 2, respectively, under the optimized conditions. PMID:25113602

  12. Regeneration of lactic and succinic acid-laden basic sorbents by leaching with a volatile base in an organic solvent

    SciTech Connect

    Husson, S.M.; King, C.J. |

    1998-08-01

    Leaching with an organic solution of a volatile base was explored as a method of regenerating tertiary amine and pyridyl sorbents. Experimental data are presented that show that regeneration efficiency correlated with the nonaqueous basicity of the regenerant as measured by the Gutmann donicity scale. Essentially complete regeneration of lactic acid-laden Dowex MWA-1 was achieved when 8--10 mol of trimethylamine were present for every mole of adsorbed acid; adequate (>70%) regeneration was obtained at a 2:1 molar ratio. The resulting trimethylamine-lactic acid complex can be thermally decomposed fully when trimethylamine is employed in an organic solvent instead of in water. A likely cause of the incomplete thermal decomposition of trimethylammonium lactate in previous, water-based systems is the aqueous environment in which the decomposition was performed.

  13. Hydrogenation of unactivated enamines to tertiary amines: rhodium complexes of fluorinated phosphines give marked improvements in catalytic activity.

    PubMed

    Tin, Sergey; Fanjul, Tamara; Clarke, Matthew L

    2015-01-01

    In the hydrogenation of sluggish unactivated enamine substrates, Rh complexes of electron-deficient phosphines are demonstrated to be far more reactive catalysts than those derived from triphenylphosphine. These operate at low catalyst loadings (down to 0.01 mol %) and are able to reduce tetrasubstituted enamines. The use of the sustainable and environmentally benign solvent (R)-limonene for the reaction is also reported with the amine isolated by acid extraction. PMID:26124864

  14. Determination of secondary and tertiary amines as N-nitrosamine precursors in drinking water system using ultra-fast liquid chromatography-tandem mass spectrometry.

    PubMed

    Wu, Qihua; Shi, Honglan; Ma, Yinfa; Adams, Craig; Eichholz, Todd; Timmons, Terry; Jiang, Hua

    2015-01-01

    N-Nitrosamines are potent mutagenic and carcinogenic emerging water disinfection by-products (DBPs). The most effective strategy to control the formation of these DBPs is minimizing their precursors from source water. Secondary and tertiary amines are dominating precursors of N-nitrosamines formation during drinking water disinfection process. Therefore, the screening and removal of these amines in source water are very essential for preventing the formation of N-nitrosamines. A rapid, simple, and sensitive ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method has been developed in this study to determine seven amines, including dimethylamine, ethylmethylamine, diethylamine, dipropylamine, trimethylamine, 3-(dimethylaminomethyl)indole, and 4-dimethylaminoantipyrine, as major precursors of N-nitrosamines in drinking water system. No sample preparation process is needed except a simple filtration. Separation and detection can be achieved in 11 min per sample. The method detection limits of selected amines are ranging from 0.02 μg/L to 1 μg/L except EMA (5 μg/L), and good calibration linearity was achieved. The developed method was applied to determine the selected precursors in source water and drinking water samples collected from Midwest area of the United States. In most of water samples, the concentrations of selected precursors of N-nitrosamines were below their method detection limits. Dimethylamine was detected in some of water samples at the concentration up to 25.4 μg/L.

  15. Comparison of the efficacy of disinfectants in automated endoscope reprocessors for colonoscopes: tertiary amine compound (Sencron2®) versus ortho-phthalaldehyde (Cidex®OPA)

    PubMed Central

    Seo, Hyun Il; Lee, Dae Sung; Yoon, Eun Mi; Kwon, Min-Jung; Park, Hyosoon; Jung, Yoon Suk; Park, Jung Ho; Sohn, Chong Il

    2016-01-01

    Background/Aims To prevent the transmission of pathogens by endoscopes, following established reprocessing guidelines is critical. An ideal reprocessing step is simple, fast, and inexpensive. Here, we evaluated and compared the efficacy and safety of two disinfectants, a tertiary amine compound (TAC) and ortho-phthalaldehyde (OPA). Methods A total of 100 colonoscopes were randomly reprocessed using two same automated endoscope reprocessors, according to disinfectant. The exposure time was 10 minutes for 0.55% OPA (Cidex® OPA, Johnson & Johnson) and 5 minutes for 4% TAC (Sencron2®, Bab Gencel Pharma & Chemical Ind. Co.). Three culture samples were obtained from each colonoscope after reprocessing. Results A total of nine samples were positive among the 300 culture samples. The positive culture rate was not statistically different between the two groups (4% for OPA and 2% for TAC, P=0.501). There were no incidents related to safety during the study period. Conclusions TAC was non-inferior in terms of reprocessing efficacy to OPA and was safe to use. Therefore, TAC seems to be a good alternative disinfectant with a relatively short exposure time and is also less expensive than OPA. PMID:27175119

  16. Economic combinative solvent and catalytic dewaxing process employing methylisopropyl ketone as the solvent and a silicate-based catalyst

    SciTech Connect

    Stem, S.C.

    1986-11-11

    This patent describes a process for the combinative dewaxing of a lubricating oil having a wax content which comprises: (a) contacting a waxy lubricating oil with a solvent comprising a ketone and an aromatic hydrocarbon selected from the group consisting of benzene, toluene, xylene and cumene in a solvent dewaxing zone, at solvent dewaxing conditions. This produces a partially dewaxed lubricating oil containing the ketone and the aromatic hydrocarbon and a slack wax stream containing hard wax, soft wax containing lubricating oil therewith, ketone, and aromatic hydrocarbon; (b) passing the partially dewaxed lubricating oil and slack wax stream to a first separation zone, and separating therein the partially dewaxed lubricating oil from the slack wax stream; (c) removing the ketone and the aromatic hydrocarbon from the partially dewaxed lubricating oil and contacting the partially dewaxed lubricating oil with a dewaxing catalyst, in a catalytic dewaxing zone, at catalytic dewaxing conditions, to produce a dewaxed lubricating oil; (d) treating, in a second dewaxing zone, the slack wax stream to separate the hard wax from the soft wax containing lubricating oil and the ketone solvent and the aromatic hydrocarbon from the slack wax stream; (e) recycling at least a portion of the ketone and aromatic hydrocarbon from step (d) to the solvent dewaxing zone of step (a) or the second dewaxing zone of step (d); and (f) passing the soft wax containing lubricating oil to a catalytic dewaxing zone to convert the soft wax and to thereby increase the produced quantity of lubricating oil. The improvement described here consists of use of the use of methylisopropyl ketone as the solvent ketone in the solvent dewaxing zone of step (a).

  17. Solvent-Dependent Facile Synthesis of Diaryl Selenides and Biphenols Employing Selenium Dioxide.

    PubMed

    Quell, Thomas; Mirion, Michael; Schollmeyer, Dieter; Dyballa, Katrin M; Franke, Robert; Waldvogel, Siegfried R

    2016-04-01

    Biphenols are important structure motifs for ligand systems in organic catalysis and are therefore included in the category of so-called "privileged ligands". We have developed a new synthetic pathway to construct these structures by the use of selenium dioxide, a stable, powerful, and commercially available oxidizer. Our new, and easy to perform protocol gives rise to biphenols and diaryl selenides depending on the solvent employed. Oxidative treatment of phenols in acetic acid yields the corresponding biphenols, whereas conversion in pyridine results in the preferred formation of diaryl selenides. As a consequence, we were able to isolate a broad scope of novel diaryl selenides, which could act as pincer-like ligands with further applications in organic synthesis or as ligands in transition metal catalysis. PMID:27308222

  18. Degradation problems with the solvent extraction organic at Roessing uranium

    SciTech Connect

    Munyungano, Brodrick; Feather, Angus; Virnig, Michael

    2008-07-01

    Roessing Uranium Ltd recovers uranium from a low-grade ore in Namibia. Uranium is recovered and purified from an ion-exchange eluate in a solvent-extraction plant. The solvent-extraction plant uses Alamine 336 as the extractant for uranium, with isodecanol used as a phase modifier in Sasol SSX 210, an aliphatic hydrocarbon diluent. Since the plant started in the mid 1970's, there have been a few episodes where the tertiary amine has been quickly and severely degraded when the plant was operated outside certain operating parameters. The Rossing experience is discussed in more detail in this paper. (authors)

  19. Efficient CO2 capture by tertiary amine-functionalized ionic liquids through Li+-stabilized zwitterionic adduct formation

    PubMed Central

    Yang, Zhen-Zhen

    2014-01-01

    Summary Highly efficient CO2 absorption was realized through formation of zwitterionic adducts, combining synthetic strategies to ionic liquids (ILs) and coordination. The essence of our strategy is to make use of multidentate cation coordination between Li+ and an organic base. Also PEG-functionalized organic bases were employed to enhance the CO2-philicity. The ILs were reacted with CO2 to form the zwitterionic adduct. Coordination effects between various lithium salts and neutral ligands, as well as the CO2 capacity of the chelated ILs obtained were investigated. For example, the CO2 capacity of PEG150MeBu2N increased steadily from 0.10 to 0.66 (mol CO2 absorbed per mol of base) through the formation of zwitterionic adducts being stabilized by Li+. PMID:25246955

  20. Determination of tertiary amines based on pH junctions and field amplification in capillary electrophoresis with electrochemiluminescence detection.

    PubMed

    Sreedhar, Mallipattu; Lin, Yang-Wei; Tseng, Wei-Lung; Chang, Huan-Tsung

    2005-08-01

    A stacking approach based on pH junction and field amplification has been developed for determining amines by capillary electrophoresis (CE) with electrochemiluminescence (ECL) detection. A two-electrode configuration was employed with an indium/tin oxide-coated glass as a working electrode and a platinum wire as a pseudoreference electrode. The ECL system also contains a flow cell (poly(dimethylsiloxane)-aluminum oxide) that was made from a mixture of Sylgard 184 silicone elastomer, a curing agent, and aluminum oxide. In order to improve the sensitivity of the present CE-ECL system using tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)(3) (2+)), a stacking approach based on pH junctions and field amplification has been tested for the analysis of triethylamine (TEA), tripropylamine (TPA), and tributylamine (TBA). Once amines (cations) prepared in citric acid solution (pH < 4.0) migrate towards the background electrolyte (15 mM sodium borate at pH 8.0), they slow down and are stacked at the boundary as a result of deprotonation and decreases in the electric field. By applying hydrodynamic injection of the sample for 60 s, this method provides the concentration limits of detection (signal-to-noise ratio = 3) of 24, 20, and 32 nM for TEA, TPA, and TBA, respectively. The results indicate that the stacking CE-ECL system is better than CE-ECL systems using a two-electrode configuration and comparable to those using a three-electrode configuration. The potential applicability of the new and low-cost CE-ECL system has been demonstrated by the determination of 1.0 microM lidocaine, a local anesthetic drug, in urine without any tedious sample preparation.

  1. Li-Ion Cells Employing Electrolytes With Methyl Propionate and Ethyl Butyrate Co-Solvents

    NASA Technical Reports Server (NTRS)

    Smart, Marshall C.; Bugga, Ratnakumar V.

    2011-01-01

    Future NASA missions aimed at exploring Mars and the outer planets require rechargeable batteries that can operate at low temperatures to satisfy the requirements of such applications as landers, rovers, and penetrators. A number of terrestrial applications, such as hybrid electric vehicles (HEVs) and electric vehicles (EVs) also require energy storage devices that can operate over a wide temperature range (i.e., -40 to +70 C), while still providing high power capability and long life. Currently, the state-of-the-art lithium-ion system has been demonstrated to operate over a wide range of temperatures (-30 to +40 C); however, the rate capability at the lower temperatures is very poor. These limitations at very low temperatures are due to poor electrolyte conductivity, poor lithium intercalation kinetics over the electrode surface layers, and poor ionic diffusion in the electrode bulk. Two wide-operating-temperature-range electrolytes have been developed based on advances involving lithium hexafluorophosphate-based solutions in carbonate and carbonate + ester solvent blends, which have been further optimized in the context of the technology and targeted applications. The approaches employed include further optimization of electrolytes containing methyl propionate (MP) and ethyl butyrate (EB), which are effective co-solvents, to widen the operating temperature range beyond the baseline systems. Attention was focused on further optimizing ester-based electrolyte formulations that have exhibited the best performance at temperatures ranging from -60 to +60 C, with an emphasis upon improving the rate capability at -20 to -40 C. This was accomplished by increasing electrolyte salt concentration to 1.20M and increasing the ester content to 60 percent by volume to increase the ionic conductivity at low temperatures. Two JPL-developed electrolytes 1.20M LiPF6 in EC+EMC+MP (20:20:60 v/v %) and 1.20M LiPF6 in EC+EMC+EB (20:20:60 v/v %) operate effectively over a wide

  2. Concentration Dependent Speciation and Mass Transport Properties of Switchable Polarity Solvents

    SciTech Connect

    Aaron D. Wilson; Christopher J. Orme

    2014-12-01

    Tertiary amine switchable polarity solvents (SPS) consisting of predominantly water, tertiary amine, and tertiary ammonium and bicarbonate ions were produced at various concentrations for three different amines: N,N-dimethylcyclohexylamine, N,N-dimethyloctylamine, and 1 cyclohexylpiperidine. For all concentrations, physical properties were measured including viscosity, molecular diffusion coefficients, freezing point depression, and density. Based on these measurements a variation on the Mark Houwink equation was developed to predict the viscosity of any tertiary amine SPS as a function of concentration using the amine’s molecular mass. The observed physical properties allowed the identification of solution state speciation of non-osmotic SPS, where the amine to carbonic acid ratio is significantly greater than one. These results indicate that at most concentrations the stoichiometric excess amine is involved in solvating a proton with two amines. The physical properties of osmotic SPS have consistent concentration dependence behavior over a wide range of concentrations; this consistence suggests osmotic pressures based on low concentrations freezing point studies can be reliably extrapolated to higher concentrations.

  3. Extraction and identification of cyclobutanones from irradiated cheese employing a rapid direct solvent extraction method.

    PubMed

    Tewfik, Ihab

    2008-01-01

    2-Alkylcyclobutanones (cyclobutanones) are accepted as chemical markers for irradiated foods containing lipid. However, current extraction procedures (Soxhlet-florisil chromatography) for the isolation of these markers involve a long and tedious clean-up regime prior to gas chromatography-mass spectrophotometry identification. This paper outlines an alternative isolation and clean-up method for the extraction of cyclobutanones in irradiated Camembert cheese. The newly developed direct solvent extraction method enables the efficient screening of large numbers of food samples and is not as resource intensive as the BS EN 1785:1997 method. Direct solvent extraction appears to be a simple, robust method and has the added advantage of a considerably shorter extraction time for the analysis of foods containing lipid.

  4. Injectible bodily prosthetics employing methacrylic copolymer gels

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-02-27

    The present invention provides novel block copolymers as structural supplements for injectible bodily prosthetics employed in medical or cosmetic procedures. The invention also includes the use of such block copolymers as nucleus pulposus replacement materials for the treatment of degenerative disc disorders and spinal injuries. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol) methyl ether polymer.

  5. Photocatalytic splitting of CS2 to S8 and a carbon-sulfur polymer catalyzed by a bimetallic ruthenium(II) compound with a tertiary amine binding site: toward photocatalytic splitting of CO2?

    PubMed

    Livanov, Konstantin; Madhu, Vedichi; Balaraman, Ekambaram; Shimon, Linda J W; Diskin-Posner, Yael; Neumann, Ronny

    2011-11-21

    The catalytic photocleavage of CS(2) to S(8) and a (C(x)S(y))(n) polymer with visible light using a dinuclear ruthenium(II) compound with a bipyridine units for photoactivity and a vicinal tertiary amine binding site for CS(2) activation was studied. The catalyst was characterized by X-ray diffraction, (1)H NMR, and (13)C NMR, ESI-MS and elemental analysis. CS(2) photocleavage was significant (240 turnovers, 20 h) to yield isolable S(8) and a (C(x)S(y))(n) polymer. A mononuclear catalyst or one without an amine binding site showed significantly less activity. XPS of the (C(x)S(y))(n) polymer showed a carbon/sulfur ratio ∼1.5-1.6 indicating that in part both C-S bonds of CS(2) had been cleaved. Catalyst was also included within the polymer. The absence of peaks in the (1)H NMR verified the (C(x)S(y))(n) nature of the polymer, while (13)C NMR and IR indicated that the polymer had multiple types of C-S and C-C bonds.

  6. Determination of the dissociation constants (pKa) of secondary and tertiary amines in organic media by capillary electrophoresis and their role in the electrophoretic mobility order inversion.

    PubMed

    Cantu, Marcelo Delmar; Hillebranda, Sandro; Carrilho, Emanuel

    2005-03-11

    Non-aqueous capillary electrophoresis (NACE) may provide a selectivity enhancement in separations since the analyte dissociation constants (pKa) in organic media are different from those in aqueous solutions. In this work, we have studied the inversion in mobility order observed in the separation of tertiary (imipramine (IMI) and amitryptiline (AMI)) and secondary amines (desipramine (DES) and nortryptiline (NOR)) in water, methanol, and acetonitrile. We have determined the pKa values in those solvents and the variation of dissociation constants with the temperature. From these data, and applying the Van't Hoff equation, we have calculated the thermodynamic parameters deltaH and deltaS. The pKa values found in methanol for DES, NOR, IMI, and AMI were 10.80, 10.79, 10.38, and 10.33, respectively. On the other hand, in acetonitrile an opposite relation was found since the values were 20.60, 20.67, 20.74, and 20.81 for DES, NOR, IMI, and AMI. This is the reason why a migration order inversion is observed in NACE for these solvents. The thermodynamic parameters were evaluated and presented a tendency that can be correlated with that observed for pKa values.

  7. Liquefaction process wherein solvents derived from the material liquefied and containing increased concentrations of donor species are employed

    DOEpatents

    Fant, B. T.; Miller, John D.; Ryan, D. F.

    1982-01-01

    An improved process for the liquefaction of solid carbonaceous materials wherein a solvent or diluent derived from the solid carbonaceous material being liquefied is used to form a slurry of the solid carbonaceous material and wherein the solvent or diluent comprises from about 65 to about 85 wt. % hydroaromatic components. The solvent is prepared by first separating a solvent or diluent distillate fraction from the liquefaction product, subjecting this distillate fraction to hydrogenation and then extracting the naphthenic components from the hydrogenated product. The extracted naphthenic components are then dehydrogenated and hydrotreated to produce additional hydroaromatic components. These components are combined with the solvent or diluent distillate fraction. The solvent may also contain hydroaromatic constituents prepared by extracting naphthenic components from a heavy naphtha, dehydrogenating the same and then hydrotreating the dehydrogenated product. When the amount of solvent produced in this manner exceeds that required for steady state operation of the liquefaction process a portion of the solvent or diluent distillated fraction will be withdrawn as product.

  8. Employability.

    ERIC Educational Resources Information Center

    Texas Tech Univ., Lubbock. Home Economics Curriculum Center.

    This workbook contains seven units designed to help secondary-level vocational education students develop the employability skills necessary to find, keep, and advance in a job. Addressed in the individual units of the workbook are the following topics: assessing individual values, abilities, and interests; finding a job; developing basic…

  9. Switchable-Hydrophilicity Solvents for Product Isolation and Catalyst Recycling in Organocatalysis.

    PubMed

    Großeheilmann, Julia; Vanderveen, Jesse R; Jessop, Philip G; Kragl, Udo

    2016-04-01

    Switchable-hydrophilicity solvents (SHSs) are solvents that can switch reversibly between a water-miscible state to a state that forms a biphasic mixture with water. In this case study, SHSs have been studied for easy product/catalyst separation as well as catalyst recycling. A series of tertiary amine SHSs have been identified for the extraction of the hydrophilic product from the postreaction mixture. Here, we determined high extraction efficiencies for the product (>84%) and low extraction rates for the catalyst (<0.1%). With the catalyst recycling experiments, we isolated the product in high purity (>98%) without further purification steps. At the same time, the catalyst was reused without any loss of activity (>91% enantiomeric excess, >99% yield) four times. Furthermore, we optimized the extraction efficiency by working with a microextractor. In addition, with the use of a falling-film microreactor, we obtained the product with high enantioselectivity by working at ambient conditions.

  10. [Chlorinated solvents and fetal damage. Spontaneous abortions, low birth weight and malformations among women employed in the dry-cleaning industry].

    PubMed

    Kolstad, H A; Brandt, L P; Rasmussen, K

    1990-08-27

    Workers in the dry-cleaning industry are exposed to vapours from the cleaning fluids, primarily perchlorethylene, which is a chlorinated solvent. Animal experiments, short-term tests for mutagenic effects and epidemiological investigations have raised the suspicion that perchlorethylene may cause reproductive failure. This investigation is an attempt to assess the risk for reproductive failure in 886 women exposed to dry-cleaning solvents while employed in dry-cleaning establishments. Twelve spontaneous abortions occurred, one infant was born with malformations and ten infants had low birth weights. A non-significant risk for spontaneous abortion was found among women with the greatest exposure. This estimate is, however, uncertain and the result must be interpreted with care. PMID:2402826

  11. Cytotoxicity evaluation of anionic nanoliposomes and nanolipoplexes prepared by the heating method without employing volatile solvents and detergents.

    PubMed

    Mozafari, M R; Reed, C J; Rostron, C

    2007-03-01

    Submicron lipid vesicles (nanoliposomes) are being used as carriers of bioactive compounds. In addition, complexes of nanoliposomes and nucleic acids (nanolipoplexes) are promising tools for the treatment of cancer, and viral and genetic disorders. Toxicity of some of these formulations, however, still remains a concern in their clinical utilisation. To address this problem, anionic liposomes were prepared by two different techniques, the conventional thin-film method, and the heating method (HM), in which no volatile organic solvent or detergent is used. An anionic nanolipoplex was constructed by incorporating plasmid DNA (pcDNA3.1/His B/lacZ) into the HM-nanoliposomes by the mediation of calcium. The toxicity of the nanoliposomes, with and without plasmid and Ca2+, was assessed using a human bronchial epithelial cell line (16HBE14o-) in the presence of serum. Cytotoxicity evaluations performed by two different assays (i.e. NRU and MTT) indicated that HM-nanoliposomes were completely non-toxic in the cell-line tested, whereas conventional liposomes revealed significant levels of toxicity. This may be due to the presence of trace amounts of chloroform and/or methanol applied during their preparation. Similar results were obtained for different sizes of lipid vesicles (prepared by 100 nm and 400 nm pore-size filters). In addition, it was observed that incorporation of DNA (15 microg/ 285 microg lipid) and Ca2+ (50 mM) to the nanoliposomes did not have any effect on their cytotoxicities. These findings indicate that the HM-liposomes have great potential as non-toxic delivery vehicles in human gene therapy and drug delivery applications while liposomes made using organic solvents should be used with caution. PMID:17416197

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    PubMed

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

    2016-09-01

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

  15. CO{sub 2} capture in flue gas: Semiempirical approach to select a potential physical solvent

    SciTech Connect

    Gwinner, B.; Roizard, D.; Lapicque, F.; Favre, E.; Cadours, R.; Boucot, P.; Carrette, P.L.

    2006-07-05

    The reported work aims at proposing a method to select potential physical solvents for CO{sub 2} absorption in flue gas. A parametric approach based on solubility data available in the open literature is engaged. It appears that CO{sub 2} capture with physical solvents is dominated by two fundamental aspects. On one hand, solvent-solvent interactions, characterized by the Hildebrand solubility parameter, have to be minimized so as to facilitate CO{sub 2} incorporation into the solvent. On the other hand, CO{sub 2}-solvent interactions, which can be estimated by ab initio calculations, have to be maximized in order to allow good cohesion between CO{sub 2} and the solvent molecules. Considering these two requirements, several types of solvents are highlighted, namely, ethers, esters, ketones, tertiary amines, and alkyl phosphates. This parametric approach differs notably from similar works about another acid gas, SO{sub 2}, and the forthcoming differences are discussed. Some mechanistic considerations are also given about the critical problems of CO{sub 2}/N{sub 2} selectivity.

  16. SWITCHABLE POLARITY SOLVENTS AS DRAW SOLUTES FOR FORWARD OSMOSIS

    SciTech Connect

    Frederick F. Stewart; Mark L. Stone; Aaron D. Wilson; Cathy Rae

    2013-03-01

    Switchable polarity solvents (SPS), mixtures of carbon dioxide, water, and tertiary amines, are presented as viable forward osmosis (FO) draw solutes allowing a novel SPS FO process. In this study substantial osmotic strengths of SPS are measured with freezing point osmometry and were demonstrated to induce competitive ?uxes at high salt concentrations on a laboratory-scale FO unit utilizing a ?at sheet cellulose triacetate (CTA) membrane. Under the experimental conditions the SPS degrades the CTA membrane; however experiments with polyamide reverse osmosis (RO) membranes display stability towards SPS. Once the draw is diluted the major fraction of the switchable polarity solvent can be mechanically separated from the puri?ed water after polar to nonpolar phase shift induced by introduction of 1 atm carbon dioxide to 1 atm of air or nitrogen with mild heating. Trace amounts of SPS can be removed from the separated water with RO in a process that avoids solution concentration polarization. The separated nonpolar phase can be regenerated to a full strength draw and recycled with the re-addition of 1 atm of carbon dioxide.

  17. Labelling of the solvent DMSO as side reaction of methylations with n.c.a. [11C]CH3I.

    PubMed

    Klein, A T; Holschbach, M

    2001-09-01

    Competing labelling of solvent dimethyl sulfoxide (DMSO) can occur during the 11C-methylation of amine precursors. A kinetic analysis of the methylation reaction of DMSO with n.c.a. [11C]CH3I was performed at 120 degrees C resulting in rate constants. The rate constant for the formation of the intermediate, methylated DMSO ([11C]DMSO-M), is compared to the reaction of [11C]CH3I with two tertiary amines, namely Dexetimide and Desmethyloxotremorine-M. The specific activity of the labelled product is reduced due to partial 12C-methylation of the precursor amines by [11C]DMSO-M in cases of significant DMSO labelling as side reaction. PMID:11515652

  18. SOLVENT EXTRACTION PROCESS

    DOEpatents

    Jonke, A.A.

    1957-10-01

    In improved solvent extraction process is described for the extraction of metal values from highly dilute aqueous solutions. The process comprises contacting an aqueous solution with an organic substantially water-immiscible solvent, whereby metal values are taken up by a solvent extract phase; scrubbing the solvent extract phase with an aqueous scrubbing solution; separating an aqueous solution from the scrubbed solvent extract phase; and contacting the scrubbed solvent phase with an aqueous medium whereby the extracted metal values are removed from the solvent phase and taken up by said medium to form a strip solution containing said metal values, the aqueous scrubbing solution being a mixture of strip solution and an aqueous solution which contains mineral acids anions and is free of the metal values. The process is particularly effective for purifying uranium, where one starts with impure aqueous uranyl nitrate, extracts with tributyl phosphate dissolved in carbon tetrachloride, scrubs with aqueous nitric acid and employs water to strip the uranium from the scrubbed organic phase.

  19. Solvent substitution

    SciTech Connect

    Not Available

    1990-01-01

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

  20. Solvent substitutes

    SciTech Connect

    Evanoff, S.P.

    1995-09-01

    The environmental and industrial hygiene regulations promulgated since 1980, most notably the Superfund Amendments and Reauthorization Act (SARA), the Hazardous and Solid Waste Amendments to the Resources Conservation and Recovery Act (RCRA), and the Clean Air Act Amendments of 1990, have brought about an increased emphasis on user exposure, hazardous waste generation, and air emissions. As a result, industry is performing a fundamental reassessment of cleaning solvents, processes, and procedures. The more progressive organizations have made their goal the elimination of solvents that may pose significant potential human health and environmental hazards. This chapter discusses solvent cleaning in metal-finishing, metal-manufacturing, and industrial maintenance applications; precision cleaning; and electronics manufacturing. Nonmetallic cleaning, adhesives, coatings, inks, and aerosols also will be addressed, but in a more cursory manner.

  1. Solvent Blending Strategy to Upgrade MCU CSSX Solvent to Equivalent Next-Generation CSSX Solvent

    SciTech Connect

    Delmau, Laetitia Helene; Moyer, Bruce A

    2012-12-01

    The results of the present study have validated an equal-volume blending strategy for upgrading freshly prepared CSSX solvent to a blended solvent functionally equivalent to NG-CSSX solvent. It is shown that blending fresh CSSX solvent as currently used in MCU with an equal volume of an NG-CSSX solvent concentrate of appropriate composition yields a blended solvent composition (46.5 mM of MaxCalix, 3.5 mM of BOBCalixC6, 0.5 M of Cs-7SB, 3 mM of guanidine suppressor, and 1.5 mM of TOA in Isopar L) that exhibits equivalent batch ESS performance to that of the NG-CSSX solvent containing 50 mM of MaxCalix, 0.5 M of Cs-7SB, and 3 mM of guanidine suppressor in Isopar L. The solvent blend composition is robust to third-phase formation. Results also show that a blend containing up to 60% v/v of CSSX solvent could be accommodated with minimal risk. Extraction and density data for the effect of solvent concentration mimicking diluent evaporation or over-dilution of the equal-volume blended solvent are also given, providing input for setting operational limits. Given that the experiments employed all pristine chemicals, the results do not qualify a blended solvent starting with actual used MCU solvent, which can be expected to have undergone some degree of degradation. Consequently, further work should be considered to evaluate this risk and implement appropriate remediation if needed.

  2. 29 CFR 1915.32 - Toxic cleaning solvents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Toxic cleaning solvents. 1915.32 Section 1915.32 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Preservation § 1915.32 Toxic cleaning solvents. (a) When toxic solvents are used, the employer shall employ...

  3. 29 CFR 1915.32 - Toxic cleaning solvents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Toxic cleaning solvents. 1915.32 Section 1915.32 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Preservation § 1915.32 Toxic cleaning solvents. (a) When toxic solvents are used, the employer shall employ...

  4. 29 CFR 1915.32 - Toxic cleaning solvents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Toxic cleaning solvents. 1915.32 Section 1915.32 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Preservation § 1915.32 Toxic cleaning solvents. (a) When toxic solvents are used, the employer shall employ...

  5. 29 CFR 1915.32 - Toxic cleaning solvents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Toxic cleaning solvents. 1915.32 Section 1915.32 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Preservation § 1915.32 Toxic cleaning solvents. (a) When toxic solvents are used, the employer shall employ...

  6. 29 CFR 1915.32 - Toxic cleaning solvents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Toxic cleaning solvents. 1915.32 Section 1915.32 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Preservation § 1915.32 Toxic cleaning solvents. (a) When toxic solvents are used, the employer shall employ...

  7. Aminosilicone solvents for CO(2) capture.

    PubMed

    Perry, Robert J; Grocela-Rocha, Teresa A; O'Brien, Michael J; Genovese, Sarah; Wood, Benjamin R; Lewis, Larry N; Lam, Hubert; Soloveichik, Grigorii; Rubinsztajn, Malgorzata; Kniajanski, Sergei; Draper, Sam; Enick, Robert M; Johnson, J Karl; Xie, Hong-bin; Tapriyal, Deepak

    2010-08-23

    This work describes the first report of the use of an aminosilicone solvent mix for the capture of CO(2). To maintain a liquid state, a hydroxyether co-solvent was employed which allowed enhanced physisorption of CO(2) in the solvent mixture. Regeneration of the capture solvent system was demonstrated over 6 cycles and absorption isotherms indicate a 25-50 % increase in dynamic CO(2) capacity over 30 % MEA. In addition, proof of concept for continuous CO(2) absorption was verified. Additionally, modeling to predict heats of reaction of aminosilicone solvents with CO(2) was in good agreement with experimental results.

  8. Solvent Immersion Imprint Lithography

    SciTech Connect

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

    2014-06-21

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

  9. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part II. Recovery of Ammonia from Sour Waters

    SciTech Connect

    Poole, L.J.; King, C.J.

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO{sub 2} and H{sub 2}S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, SUCCiOlC acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The concentration

  10. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part I. Regeneration of Amine-Carboxylic Acid Extracts

    SciTech Connect

    Poole, L.J.; King, C.J.

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO{sub 2} and H{sub 2}S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, succinic acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The concentration

  11. Solvent wash solution

    DOEpatents

    Neace, James C.

    1986-01-01

    Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

  12. Solvent wash solution

    DOEpatents

    Neace, J.C.

    1984-03-13

    A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

  13. NEPTUNIUM SOLVENT EXTRACTION PROCESS

    DOEpatents

    Dawson, L.R.; Fields, P.R.

    1959-10-01

    The separation of neptunium from an aqueous solution by solvent extraction and the extraction of neptunium from the solvent solution are described. Neptunium is separated from an aqueous solution containing tetravalent or hexavalent neptunium nitrate, nitric acid, and a nitrate salting out agent, such as sodium nitrate, by contacting the solution with an organic solvent such as diethyl ether. Subsequently, the neptunium nitrate is extracted from the organic solvent extract phase with water.

  14. Solvents safety handbook

    SciTech Connect

    De Renzo, D.J.

    1986-01-01

    Know solvents and how to protect yourself from dangerous exposure to them. Instant information for decision-making regarding industrial solvents in everyday use, is provided in this handbook which is a compilation of data on 335 hazardous and frequently-used solvents.

  15. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-11-01

    To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were later confirmed by magnetic resonance imaging at Argonne National Lab and the University of Illinois.

  16. Environmental Impacts on Nuclear Reprocessing Solvents

    NASA Astrophysics Data System (ADS)

    Gillens, A. R.; Fessenden, J. E.

    2009-12-01

    Nuclear tests have been employed ever since the first nuclear explosion in Alamogordo, NM during the mid-1940s. Nuclear weapons pose a threat to civil society and result in extensive biological (medical) damages. For this reason, treaties banning nuclear tests and weapons have been employed since the 1960s to cease proliferation of weapons. However, as nuclear tests continue in secrecy and actinides, such as plutonium and uranium, are eligible for theft, nuclear forensics is needed to prevent weapons proliferation. In this study, solvents [tributyl phosphate (TBP), dodecane, decanol] used in reprocessing spent nuclear fuel are analyzed using an isotope ratio mass spectrometer, which provides indisputable evidence in identifying the operation in which solvents were used. Solvent samples are observed under variable conditions in the laboratory for different time periods. It is assumed that their carbon isotope values (δ13C) will become more positive (shift heavy) with time. It is found that the solvents are hygroscopic. TBP leaves the most robust signature compared to the other solvents studied and the isotope values for all solvents under all conditions become more positive with time. This study serves as primary research in understanding how solvents behave under variable conditions in the laboratory and how this could be translated to the environment in fate and transport studies.

  17. Calculating the binding free energies of charged species based on explicit-solvent simulations employing lattice-sum methods: An accurate correction scheme for electrostatic finite-size effects

    NASA Astrophysics Data System (ADS)

    Rocklin, Gabriel J.; Mobley, David L.; Dill, Ken A.; Hünenberger, Philippe H.

    2013-11-01

    calculations for a given system, its dependence on the box size being analytical. The latter scheme also provides insight into the physical origin of the finite-size effects. These two schemes also encompass a correction for discrete solvent effects that persists even in the limit of infinite box sizes. Application of either scheme essentially eliminates the size dependence of the corrected charging free energies (maximal deviation of 1.5 kJ mol-1). Because it is simple to apply, the analytical correction scheme offers a general solution to the problem of finite-size effects in free-energy calculations involving charged solutes, as encountered in calculations concerning, e.g., protein-ligand binding, biomolecular association, residue mutation, pKa and redox potential estimation, substrate transformation, solvation, and solvent-solvent partitioning.

  18. Calculating the binding free energies of charged species based on explicit-solvent simulations employing lattice-sum methods: An accurate correction scheme for electrostatic finite-size effects

    SciTech Connect

    Rocklin, Gabriel J.; Mobley, David L.; Dill, Ken A.; Hünenberger, Philippe H.

    2013-11-14

    -periodic PB calculations for a given system, its dependence on the box size being analytical. The latter scheme also provides insight into the physical origin of the finite-size effects. These two schemes also encompass a correction for discrete solvent effects that persists even in the limit of infinite box sizes. Application of either scheme essentially eliminates the size dependence of the corrected charging free energies (maximal deviation of 1.5 kJ mol{sup −1}). Because it is simple to apply, the analytical correction scheme offers a general solution to the problem of finite-size effects in free-energy calculations involving charged solutes, as encountered in calculations concerning, e.g., protein-ligand binding, biomolecular association, residue mutation, pK{sub a} and redox potential estimation, substrate transformation, solvation, and solvent-solvent partitioning.

  19. Solvents and sustainable chemistry

    PubMed Central

    Welton, Tom

    2015-01-01

    Solvents are widely recognized to be of great environmental concern. The reduction of their use is one of the most important aims of green chemistry. In addition to this, the appropriate selection of solvent for a process can greatly improve the sustainability of a chemical production process. There has also been extensive research into the application of so-called green solvents, such as ionic liquids and supercritical fluids. However, most examples of solvent technologies that give improved sustainability come from the application of well-established solvents. It is also apparent that the successful implementation of environmentally sustainable processes must be accompanied by improvements in commercial performance. PMID:26730217

  20. Solvent recycle/recovery

    SciTech Connect

    Paffhausen, M.W.; Smith, D.L.; Ugaki, S.N.

    1990-09-01

    This report describes Phase I of the Solvent Recycle/Recovery Task of the DOE Chlorinated Solvent Substitution Program for the US Air Force by the Idaho National Engineering Laboratory, EG G Idaho, Inc., through the US Department of Energy, Idaho Operations Office. The purpose of the task is to identify and test recovery and recycling technologies for proposed substitution solvents identified by the Biodegradable Solvent Substitution Program and the Alternative Solvents/Technologies for Paint Stripping Program with the overall objective of minimizing hazardous wastes. A literature search to identify recycle/recovery technologies and initial distillation studies has been conducted. 4 refs.

  1. Used lubricating oil recycling using hydrocarbon solvents.

    PubMed

    Hamad, Ahmad; Al-Zubaidy, Essam; Fayed, Muhammad E

    2005-01-01

    A solvent extraction process using new hydrocarbon solvents was employed to treat used lubricant oil. The solvents used were liquefied petroleum gas (LPG) condensate and stabilized condensate. A demulsifier was used to enhance the treatment process. The extraction process using stabilized condensate demonstrated characteristics that make it competitive with existing used oil treatment technologies. The process is able to reduce the asphaltene content of the treated lubricating oil to 0.106% (w/w), the ash content to 0.108%, and the carbon residue to 0.315% with very low levels of contaminant metals. The overall yield of oil is 79%. The treated used oil can be recycled as base lubricating oil. The major disadvantage of this work is the high temperature of solvent recovery. Experimental work and results are presented in detail. PMID:15627468

  2. Implicit solvent methods for free energy estimation

    PubMed Central

    Decherchi, Sergio; Masetti, Matteo; Vyalov, Ivan; Rocchia, Walter

    2014-01-01

    Solvation is a fundamental contribution in many biological processes and especially in molecular binding. Its estimation can be performed by means of several computational approaches. The aim of this review is to give an overview of existing theories and methods to estimate solvent effects giving a specific focus on the category of implicit solvent models and their use in Molecular Dynamics. In many of these models, the solvent is considered as a continuum homogenous medium, while the solute can be represented at the atomic detail and at different levels of theory. Despite their degree of approximation, implicit methods are still widely employed due to their trade-off between accuracy and efficiency. Their derivation is rooted in the statistical mechanics and integral equations disciplines, some of the related details being provided here. Finally, methods that combine implicit solvent models and molecular dynamics simulation, are briefly described. PMID:25193298

  3. Engaging Employers?

    ERIC Educational Resources Information Center

    Hillier, Yvonne

    2008-01-01

    A key factor in the successful development of workplace learning is employer engagement (Leitch, 2006; DfES, 2007). However, despite numerous approaches by government in the United Kingdom to bring together employers, providers and learners so that economic success is generated by a skilled and flexible workforce, there continue to be challenges…

  4. Maternal Employment

    ERIC Educational Resources Information Center

    Clark, Sam

    1975-01-01

    The overwhelming evidence from years of research is that maternal employment, by itself, has little influence on the behaviors of children. More relevant issues are: mother's reasons for working, family's acceptance of mother's employment, quality of substitute child care, family's social and emotional health, and economic conditions. (Author/AJ)

  5. Industry Employment

    ERIC Educational Resources Information Center

    Occupational Outlook Quarterly, 2010

    2010-01-01

    This article illustrates projected employment change from an industry perspective over the 2008-2018 decade. Workers are grouped into an industry according to the type of good produced or service provided by the establishment in which they work. Industry employment projections are shown in terms of numeric change (growth or decline in the total…

  6. Industry Employment

    ERIC Educational Resources Information Center

    Occupational Outlook Quarterly, 2012

    2012-01-01

    This article illustrates projected employment change by industry and industry sector over 2010-20 decade. Workers are grouped into an industry according to the type of good produced or service provided by the establishment for which they work. Industry employment projections are shown in terms of numeric change (growth or decline in the total…

  7. Solvent-free synthesis

    EPA Science Inventory

    This chapter gives a brief introduction about solvent-free reactions whose importance can be gauged by the increasing number of publications every year during the last decade. The mechanistic aspects of the reactions under solvent-free conditions have been highlighted. Our observ...

  8. SOLVENT EXTRACTION OF NEPTUNIUM

    DOEpatents

    Butler, J.P.

    1958-08-12

    A process is described for the recovery of neptuniunn from dissolver solutions by solvent extraction. The neptunium containing solution should be about 5N, in nitric acid.and about 0.1 M in ferrous ion. The organic extracting agent is tributyl phosphate, and the neptuniunn is recovered from the organic solvent phase by washing with water.

  9. Alternative Green Solvents Project

    NASA Technical Reports Server (NTRS)

    Maloney, Phillip R.

    2012-01-01

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

  10. Employment of High-Performance Thin-Layer Chromatography for the Quantification of Oleuropein in Olive Leaves and the Selection of a Suitable Solvent System for Its Isolation with Centrifugal Partition Chromatography.

    PubMed

    Boka, Vasiliki-Ioanna; Argyropoulou, Aikaterini; Gikas, Evangelos; Angelis, Apostolis; Aligiannis, Nektarios; Skaltsounis, Alexios-Leandros

    2015-11-01

    A high-performance thin-layer chromatographic methodology was developed and validated for the isolation and quantitative determination of oleuropein in two extracts of Olea europaea leaves. OLE_A was a crude acetone extract, while OLE_AA was its defatted residue. Initially, high-performance thin-layer chromatography was employed for the purification process of oleuropein with fast centrifugal partition chromatography, replacing high-performance liquid-chromatography, in the stage of the determination of the distribution coefficient and the retention volume. A densitometric method was developed for the determination of the distribution coefficients, KC = CS/CM. The total concentrations of the target compound in the stationary phase (CS) and in the mobile phase (CM) were calculated by the area measured in the high-performance thin-layer chromatogram. The estimated Kc was also used for the calculation of the retention volume, VR, with a chromatographic retention equation. The obtained data were successfully applied for the purification of oleuropein and the experimental results confirmed the theoretical predictions, indicating that high-performance thin-layer chromatography could be an important counterpart in the phytochemical study of natural products. The isolated oleuropein (purity > 95%) was subsequently used for the estimation of its content in each extract with a simple, sensitive and accurate high-performance thin-layer chromatography method. The best fit calibration curve from 1.0 µg/track to 6.0 µg/track of oleuropein was polynomial and the quantification was achieved by UV detection at λ 240 nm. The method was validated giving rise to an efficient and high-throughput procedure, with the relative standard deviation % of repeatability and intermediate precision not exceeding 4.9% and accuracy between 92% and 98% (recovery rates). Moreover, the method was validated for robustness, limit of quantitation, and limit of detection. The amount of oleuropein for

  11. Solvent-cast three-dimensional printing of multifunctional microsystems.

    PubMed

    Guo, Shuang-Zhuang; Gosselin, Frédérick; Guerin, Nicolas; Lanouette, Anne-Marie; Heuzey, Marie-Claude; Therriault, Daniel

    2013-12-20

    The solvent-cast direct-write fabrication of microstructures is shown using a thermoplastic polymer solution ink. The method employs the robotically controlled microextrusion of a filament combined with a rapid solvent evaporation. Upon drying, the increased rigidity of the extruded filament enables the creation of complex freeform 3D shapes.

  12. Microencapsulation of terbutaline sulphate by the solvent evaporation technique.

    PubMed

    Manekar, N C; Puranik, P K; Joshi, S B

    1992-01-01

    Terbutaline sulphate microcapsules were prepared by coacervation-phase separation (solvent evaporation) technique using ethyl cellulose as a coating material. Acetone, ethyl alcohol and isopropyl alcohol were employed as solvents for coating material. Microcapsules were evaluated for their drug content, particle size distribution (microscopic method), flow properties, bulk density, in vitro dissolution, drug release kinetics and surface characteristics (scanning electron microscopy). PMID:1403496

  13. Use of inhibitory solvents in multi-membrane bioreactor

    NASA Technical Reports Server (NTRS)

    Cho, Toohyon (Inventor); Shuler, Michael L. (Inventor)

    1990-01-01

    An immobilized liquid membrane is employed to allow use of a product-extracting solvent which is normally toxic toward a cell layer which produces the product in a membrane-moderated biological reaction.

  14. CHEMICAL TRANSFORMATIONS USING NON-TRADITIONAL APPROACHES: MICROWAVE-ASSISTED GREENER SYNTHESES IN AQUEOUS MEDIA OR UNDER SOLVENT-FREE CONDITIONS

    EPA Science Inventory

    Microwave (MW) irradiation in conjunction with water as reaction media has proven to be a 'greener' chemical approach for expeditious N-alkylation reactions of amines and hydrazines wherein the reactions under mildly basic conditions afford tertiary amines and double N<...

  15. Solvent alternatives guide

    SciTech Connect

    Elion, J.M.; Monroe, K.R.; Hill, E.A.

    1996-06-01

    It is no longer legal to manufacture or import chlorofluorocarbon 113 or methyl chloroform solvents, and companies that currently clean their parts with either material are now required to implement environmentally safe substitutes. To help find alternative methods, Research Triangle Institute`s Surface Cleaning Technology Program has designed a Solvent Alternatives Guide (SAGE), an online tool that enables access to practical information and recommendations for acceptable solvents. Developed in partnership with the US Environmental Protection Agency, SAGE is available free of charge on the Internet`s World Wide Web.

  16. An example of regioselective esterification by intramolecular acyl transfer from a tertiary amine

    SciTech Connect

    Waddell, T.G.; Rambalakos, T.; Christie, K.R. )

    1990-07-20

    Despite the fact that the famous antimarlarial quinine (1) has been known for 170 years, there is still considerable interest in its chemical and biological properties. Much of the most recent attention is due to the utility of quinine as a chiral resolving agent and catalyst. Important and new chemistry of quinine may yet be discovered. To this point, the authors became interested in constructing quinine derivatives which have built into their structures electrophilic centers which might make covalent bonds with cellular protein or nucleic acid nucleophilic sites. In order to preserve the noncovalent binding properties of quinine, functionalization and derivatization of the remote vinyl group were desired. In an esterification step of the derivatization, a structurally hindered ester was formed, to our surprise. The mechanism for this regioselective reaction are discussed.

  17. Primary, secondary, and tertiary amines for CO2 capture: designing for mesoporous CO2 adsorbents.

    PubMed

    Ko, Young Gun; Shin, Seung Su; Choi, Ung Su

    2011-09-15

    CO(2) emissions, from fossil-fuel-burning power plants, the breathing, etc., influence the global worming on large scale and the man's work efficiency on small scale. The reversible capture of CO(2) is a prominent feature of CO(2) organic-inorganic hybrid adsorbent to sequester CO(2). Herein, (3-aminopropyl) trimethoxysilane (APTMS), [3-(methylamino)propyl] trimethoxysilane (MAPTMS), and [3-(diethylamino) propyl] trimethoxysilane (DEAPTMS) are immobilized on highly ordered mesoporous silicas (SBA-15) to catch CO(2) as primary, secondary, and tertiary aminosilica adsorbents. X-ray photoelectron spectroscopy was used to analyze the immobilized APTMS, MAPTMS, and DEAPTMS on the SBA-15. We report an interesting discovery that the CO(2) adsorption and desorption on the adsorbent depend on the amine type of the aminosilica adsorbent. The adsorbed CO(2) was easily desorbed from the adsorbent with the low energy consumption in the order of tertiary, secondary, and primary amino-adsorbents while the adsorption amount and the bonding-affinity increased in the reverse order. The effectiveness of amino-functionalized (1(o), 2(o), and 3(o) amines) SBA-15s as a CO(2) capturing agent was investigated in terms of adsorption capacity, adsorption-desorption kinetics, and thermodynamics. This work demonstrates apt amine types to catch CO(2) and regenerate the adsorbent, which may open new avenues to designing "CO(2) basket". PMID:21708387

  18. Effects of tertiary amine local anesthetics on the assembly and disassembly of brain microtubules in vitro.

    PubMed

    Genna, J M; Coffe, G; Pudles, J

    1980-09-01

    From kinetic and electron microscopy studies on the effects of procaine, tetracaine and dibucaine on the polymerization and depolymerization of the microtubules isolated from pig and rat brains the following results were obtained. 1. Procaine or tetracaine, at the concentration range of 0.5--20 mM and of 0.5--5 mM respectively, increases the rate of tubulin polymerization (24 degrees C or 37 degrees C) and of microtubule depolymerization (4 degrees C) as a linear function of the concentration of the anesthetics, while identical amounts of microtubules are formed. In the absence of microtubule-associated proteins the polymerization of tubulin is not induced by 10 mM procaine, furthermore, the critical concentration of microtubule proteins necessary for assembly into microtubules is not affected at this concentration level of the anesthetic. This suggests that procaine affects not the nucleation, but rather the elongation process. 2. Dibucaine, from 0.5 mM to 3 mM increases the lag time of the polymerization reaction, while from 0.5 mM to 2 mM it linearly decreases both tubulin polymerization (24 degrees C) and microtubule depolymerization (4 degrees C) rates. Dibucaine, up to mM concentration, does not affect the extent of tubulin polymerization; however, above this concentration it induces the formation of amorphous aggregates. 3. Procaine or tetracaine enhances the depolymerizing effect of calcium on microtubules. The half-maximal values for the depolymerizing effect of calcium were 0.96, 0.71 and 0.51 mM for the control, in the presence of 10 mM procaine and 5 mM tetracaine respectively. PMID:7439170

  19. Reaction mechanisms of secondary and tertiary amines with OH and NO3 radicals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emissions of aliphatic amines are common near agricultural facilities such as animal feed lots. Determining the reactions of these amines with common atmospheric radicals is important to understanding both daytime and nighttime atmospheric chemistry. Several smog chamber experiments were conducted ...

  20. NEW CATHEPSIN D INHIBITOR LIBRARY UTILIZING HYDROXYETHYL ISOSTERES WITH CYCLIC TERTIARY AMINES

    PubMed Central

    McConnell, Rose M.; Inapudi, Kalyani; Kadasala, Naveen; Yarlagadda, Karthika; Velusamy, Priya; McConnell, Matthew S.; Green, Adam; Trana, Carol; Sayyar, Kelley; McConnell, James S.

    2012-01-01

    The design and synthesis of hydroxyethylamine isosteres as inhibitors of cathepsin D based on SAR data has been accomplished. A library of 96 of these hydroxyethylamine isosteres are described and many have proven to be very potent inhibitors of human cathepsin D activity as measured using a fluorometric assay technique, via peptide substrate Ac-Glu-Glu(Edans)-Lys-Pro-Ile-Cys-Phe-Phe-Arg-Leu-Gly-Lys(Methyl Red)-Glu-NH2. Compounds showing strongest inhibition of cathepsin D activity were those that contain a hydroxyethyl-N’-2- or N’-(4-chlorophenyl)piperazine moiety (IC50 values range from 0.55 to 8.5 nM), with N’-(2-pyrimidyl)piperizine (IC50 values range from 0.5 to 21.6 nM), with N-N’-L-piperazinocolinamide (IC50 values range from 0.001 – 0.25 nM), or N-N’-L-piperazinocolin-N-methylamide (IC50 values range from 0.015 – 7.3 nM) . PMID:22830497

  1. CHLORINATED SOLVENT PLUME CONTROL

    EPA Science Inventory

    This lecture will cover recent success in controlling and assessing the treatment of shallow ground water plumes of chlorinated solvents, other halogenated organic compounds, and methyl tert-butyl ether (MTBE).

  2. SOLVENT WASTE REDUCTION ALTERNATIVES

    EPA Science Inventory

    This publication contains edited versions of presentations on this subject made at five Technology Transfer seminars in 1988. Chapters are included on land disposal regulations and requirements; waste solvent disposal alternatives from various industries such as process equipment...

  3. Solvent-free fluidic organic dye lasers.

    PubMed

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

    2013-05-01

    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.

  4. Continuous countercurrent membrane column for the separation of solute/solvent and solvent/solvent systems

    DOEpatents

    Nerad, Bruce A.; Krantz, William B.

    1988-01-01

    A reverse osmosis membrane process or hybrid membrane - complementary separator process for producing enriched product or waste streams from concentrated and dilute feed streams for both solvent/solvent and solute/solvent systems is described.

  5. Supercritical solvent coal extraction

    NASA Technical Reports Server (NTRS)

    Compton, L. E. (Inventor)

    1984-01-01

    Yields of soluble organic extract are increased up to about 50% by the supercritical extraction of particulate coal at a temperature below the polymerization temperature for coal extract fragments (450 C.) and a pressure from 500 psig to 5,000 psig by the conjoint use of a solvent mixture containing a low volatility, high critical temperature coal dissolution catalyst such as phenanthrene and a high volatility, low critical temperature solvent such as toluene.

  6. SOLVENT EXTRACTION OF RUTHENIUM

    DOEpatents

    Hyman, H.H.; Leader, G.R.

    1959-07-14

    The separation of rathenium from aqueous solutions by solvent extraction is described. According to the invention, a nitrite selected from the group consisting of alkali nitrite and alkaline earth nitrite in an equimolecular quantity with regard to the quantity of rathenium present is added to an aqueous solution containing ruthenium tetrantrate to form a ruthenium complex. Adding an organic solvent such as ethyl ether to the resulting mixture selectively extracts the rathenium complex.

  7. Cleaning without chlorinated solvents

    SciTech Connect

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

    1994-12-31

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

  8. Cleaning without chlorinated solvents

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  9. Neurotoxicity of solvents.

    PubMed

    Sainio, Markku Alarik

    2015-01-01

    Worldwide, several hundred million tons of organic solvents are used annually in household, industry, and other occupational settings. Millions of workers are regularly exposed to organic solvents considered neurotoxic. Acute neurotoxicity due to high exposure of solvent is usually evident, but the nature of long-term effects, such as chronic solvent encephalopathy (CSE), has raised uncertainty even among experts. Earlier studies were criticized for their methodology, mainly epidemiologic studies or investigations of exposed groups with many possible confounders and inadequate exposure assessment. However, an increasing number of studies have been performed since, also on workers with defined CSE based on differential diagnostics. During the last decade, evidence has emerged to enable identification of CSE, a necessity for the early recognition and prevention of progression of dysfunction and disability. Selected chemicals are presented here due to their widespread use, neurotoxic potential, and ability to cause solvent encephalopathy. Constant introduction of new chemicals may introduce new hazardous chemicals or known chemicals may reveal new health effects. It is important to keep an open mind for new findings of solvent-related neurobehavioral effects. PMID:26563785

  10. LLNL solvent substitution

    SciTech Connect

    Benkovitch, M.G.

    1992-12-01

    Allied-Signal Inc., Kansas City Division (KCD), manufactures the electrical, electromechanical, mechanical, and plastic components for nuclear weapons. The KCD has made a commitment to eliminate the use of chlorohydrocarbon (CHC) and chlorofluorocarbon (CFC) solvents to the greatest technical extent possible consistent with nuclear safety and stockpile reliability requirements by July 1993. Several non-halogenated solvents (Exxate 1000, Bioact EC-7, Bioact EC-7R, d-limonene, ACT-100, Kester 5769, and isopropyl alcohol) were evaluated to determine the most effective, non-chlorinated non-fluorinated, alternate solvent cleaning system for a particular electronic assembly in lieu of the current trichloroethylenefisopropyl alcohol baseline cleaning process. All of these solvents were evaluated using current manual spray cleaning processes. The solvents were evaluated for their effectiveness in removing a rosin based RMA solder flux, a particular silicone mold release, and a wide variety of general contaminants (oils, greases, mold releases, resins, etc.) normally found in production departments. A DI water/isopropyl alcohol spray cleaning process was also evaluated for removing two organic acid fluxes. Test samples were contaminated, spray cleaned with the appropriate solvent, and then analyzed for cleanliness. The Meseran Surface Analyzer was used to measure,, organic contamination on the samples before and after cleaning. An Omega Meter Model 600 was also used to detect solder flux residues.

  11. Occupational Employment

    ERIC Educational Resources Information Center

    Occupational Outlook Quarterly, 2010

    2010-01-01

    When choosing a career, jobseekers often want to know which occupations offer the best prospects. Generally, occupations that have rapid job growth, many new jobs, or many job openings--and good wages--promise better opportunities. This article shows how employment in particular occupations is projected to change over the 2008-2018 decade. The…

  12. Occupational Employment

    ERIC Educational Resources Information Center

    Occupational Outlook Quarterly, 2012

    2012-01-01

    When choosing a career, jobseekers often want to know which occupations offer the best prospects. Generally, occupations that have rapid job growth, many new jobs, or many job openings--and good wages--promise better opportunities. This paper shows how employment in particular occupations is projected to change from 2010 to 2020. It presents…

  13. Method and system for ethanol production

    DOEpatents

    Feder, H.M.; Chen, M.J.

    1980-05-21

    A transition metal carbonyl and a tertiary amine are employed as a homogeneous catalytic system in methanol or a less volatile solvent to react methanol with carbon monoxide and hydrogen gas producing ethanol and carbon dioxide. The gas contains a high carbon monoxide to hydrogen ratio as is present in a typical gasifier product. The reaction has potential for anhydrous ethanol production as carbon dioxide rather than water is produced. The only other significant by-product is methane. Selected transition metal carbonyls include those of iron, ruthenium and possibly manganese and osmium. Selected amines include trimethylamine, N-Methylpyrrolidine, 24-diazabicyclooctane, dimethyneopentylamine and 2-pryidinol.

  14. Method and system for ethanol production

    DOEpatents

    Feder, Harold M.; Chen, Michael J.

    1983-01-01

    A transition metal carbonyl and a tertiary amine are employed as a homogeneous catalytic system in methanol or a less volatile solvent to react methanol with carbon monoxide and hydrogen gas producing ethanol and carbon dioxide. The gas contains a high carbon monoxide to hydrogen ratio as is present in a typical gasifier product. The reaction has potential for anhydrous ethanol production as carbon dioxide rather than water is produced. Selected transition metal carbonyls include those of iron, rhodium ruthenium, manganese in combination with iron and possibly osmium. Selected amines include trimethylamine, N-Methylpyrrolidine, 2,4-diazabicyclooctane, dimethylneopentylamine, N-methylpiperidine and derivatives of N-methylpiperidine.

  15. Method and system for ethanol production

    DOEpatents

    Feder, Harold M.; Chen, Michael J.

    1981-01-01

    A transition metal carbonyl and a tertiary amine are employed as a homogeneous catalytic system in methanol or a less volatile solvent to react methanol with carbon monoxide and hydrogen gas producing ethanol and carbon dioxide. The gas contains a high carbon monoxide to hydrogen ratio as is present in a typical gasifier product. The reaction has potential for anhydrous ethanol production as carbon dioxide rather than water is produced. The only other significant by product is methane. Selected transition metal carbonyls include those of iron, ruthenium and possibly manganese and osmium. Selected amines include trimethylamine, N-Methylpyrrolidine, 24-diazabicyclooctane, dimethyneopentylamine and 2-pryidinol.

  16. Method and system for ethanol production

    DOEpatents

    Feder, H.M.; Chen, M.J.

    1981-09-24

    A transition metal carbonyl and a tertiary amine are employed as a homogeneous catalytic system in methanol or a less volatile solvent to react methanol with carbon monoxide and hydrogen gas producing ethanol and carbon dioxide. The gas contains a high carbon monoxide to hydrogen ratio as is present in a typical gasifier product. The reaction has potential for anhydrous ethanol production as carbon dioxide rather than water is produced. Selected transition metal carbonyls include those of iron, rhodium, ruthenium, manganese in combination with iron and possibly osmium. Selected amines include trimethylamine, N-Methylpyrrolidine, 2,4-diazabicyclooctane, dimethylneopentylamine, N-methylpiperidine and derivatives of N-methylpiperidine.

  17. Method for destroying halocarbon compositions using a critical solvent

    DOEpatents

    Ginosar, Daniel M.; Fox, Robert V.; Janikowski, Stuart K.

    2006-01-10

    A method for destroying halocarbons. Halocarbon materials are reacted in a dehalogenation process wherein they are combined with a solvent in the presence of a catalyst. A hydrogen-containing solvent is preferred which functions as both a solvating agent and hydrogen donor. To augment the hydrogen donation capacity of the solvent if needed (or when non-hydrogen-containing solvents are used), a supplemental hydrogen donor composition may be employed. In operation, at least one of the temperature and pressure of the solvent is maintained near, at, or above a critical level. For example, the solvent may be in (1) a supercritical state; (2) a state where one of the temperature or pressure thereof is at or above critical; or (3) a state where at least one of the temperature and pressure thereof is near-critical. This system provides numerous benefits including improved reaction rates, efficiency, and versatility.

  18. Organic syntheses employing supercritical carbon dioxide as a reaction solvent

    NASA Technical Reports Server (NTRS)

    Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

    1991-01-01

    Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

  19. Organic syntheses employing supercritical carbon dioxide as a reaction solvent

    NASA Technical Reports Server (NTRS)

    Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

    1993-01-01

    Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

  20. Alternative Solvents through Green Chemistry Project

    NASA Technical Reports Server (NTRS)

    Hintze, Paul E.; Quinn, Jacqueline

    2014-01-01

    Components in the aerospace industry must perform with accuracy and precision under extreme conditions, and surface contamination can be detrimental to the desired performance, especially in cases when the components come into contact with strong oxidizers such as liquid oxygen. Therefore, precision cleaning is an important part of a components preparation prior to utilization in aerospace applications. Current cleaning technologies employ a variety of cleaning agents, many of which are halogenated solvents that are either toxic or cause environmental damage. Thus, this project seeks to identify alternative precision cleaning solvents and technologies, including use of less harmful cleaning solvents, ultrasonic and megasonic agitation, low-pressure plasma cleaning techniques, and supercritical carbon dioxide extraction. Please review all data content found in the Public Data tab located at: https:techport.nasa.govview11697public

  1. Halogenated solvent remediation

    DOEpatents

    Sorenson, Kent S.

    2004-08-31

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

  2. Halogenated solvent remediation

    DOEpatents

    Sorenson, Jr., Kent S.

    2008-11-11

    Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

  3. Separation by solvent extraction

    DOEpatents

    Holt, Jr., Charles H.

    1976-04-06

    17. A process for separating fission product values from uranium and plutonium values contained in an aqueous solution, comprising adding an oxidizing agent to said solution to secure uranium and plutonium in their hexavalent state; contacting said aqueous solution with a substantially water-immiscible organic solvent while agitating and maintaining the temperature at from -1.degree. to -2.degree. C. until the major part of the water present is frozen; continuously separating a solid ice phase as it is formed; separating a remaining aqueous liquid phase containing fission product values and a solvent phase containing plutonium and uranium values from each other; melting at least the last obtained part of said ice phase and adding it to said separated liquid phase; and treating the resulting liquid with a new supply of solvent whereby it is practically depleted of uranium and plutonium.

  4. Breathing with chlorinated solvents

    SciTech Connect

    McCarty, P.L.

    1997-06-06

    Chlorinated solvents are effective cleaners and in the past dirted solvents were dumped into landfills, stored in tanks that often leaked, or spilled. As a result the most common contaminants of organic groundwater at hazardous waste sites are the two major chlorinated solvents - tetrachloroethylene (PCE) and trichloroethylene (TCE). Both are suspected carcinogens and both are highly resistant to biodegradation. Now however, there is a report of a bacterium that can remove all of the chlorine atoms from both by halorespiration to form ethene, an innocuous end product. This article goes on to discuss the background of biodegradation of chlorinated compounds, why it is so difficult, and what the future is in this area. 9 refs., 1 fig.

  5. Safe battery solvents

    DOEpatents

    Harrup, Mason K.; Delmastro, Joseph R.; Stewart, Frederick F.; Luther, Thomas A.

    2007-10-23

    An ion transporting solvent maintains very low vapor pressure, contains flame retarding elements, and is nontoxic. The solvent in combination with common battery electrolyte salts can be used to replace the current carbonate electrolyte solution, creating a safer battery. It can also be used in combination with polymer gels or solid polymer electrolytes to produce polymer batteries with enhanced conductivity characteristics. The solvents may comprise a class of cyclic and acyclic low molecular weight phosphazenes compounds, comprising repeating phosphorus and nitrogen units forming a core backbone and ion-carrying pendent groups bound to the phosphorus. In preferred embodiments, the cyclic phosphazene comprises at least 3 phosphorus and nitrogen units, and the pendent groups are polyethers, polythioethers, polyether/polythioethers or any combination thereof, and/or other groups preferably comprising other atoms from Group 6B of the periodic table of elements.

  6. Organic solvent topical report

    SciTech Connect

    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.

  7. ONSITE SOLVENT RECOVERY

    EPA Science Inventory

    This study evaluated the product quality, waste reduction/pollution prevention, and economic aspects of three technologies for onsite solvent recovery. The technologies were (1) atmospheric batch distillation, (2) vacuum heat-pump distillation, and (3) low-emission vapor degreas...

  8. Organic solvent topical report

    SciTech Connect

    COWLEY, W.L.

    1999-05-13

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

  9. DESIGNING GREENER SOLVENTS

    EPA Science Inventory

    Computer-aided design of chemicals and chemical mixtures provides a powerful tool to help engineers identify cleaner process designs and more-benign alternatives to toxic industrial solvents. Three software programs are discussed: (1) PARIS II (Program for Assisting the Replaceme...

  10. Solvent vapor collector

    DOEpatents

    Ellison, Kenneth; Whike, Alan S.

    1979-01-30

    A solvent vapor collector is mounted on the upstream inlet end of an oven having a gas-circulating means and intended for curing a coating applied to a strip sheet metal at a coating station. The strip sheet metal may be hot and solvent vapors are evaporated at the coating station and from the strip as it passes from the coating station to the oven. Upper and lower plenums within a housing of the collector are supplied with oven gases or air from the gas-circulating means and such gases or air are discharged within the collector obliquely in a downstream direction against the strip passing through that collector to establish downstream gas flows along the top and under surfaces of the strip so as, in turn, to induct solvent vapors into the collector at the coating station. A telescopic multi-piece shroud is usefully provided on the housing for movement between an extended position in which it overlies the coating station to collect solvent vapors released thereat and a retracted position permitting ready cleaning and adjustment of that coating station.

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

    SciTech Connect

    Oshima, Hiraku; Kinoshita, Masahiro

    2015-04-14

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

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

    NASA Astrophysics Data System (ADS)

    Oshima, Hiraku; Kinoshita, Masahiro

    2015-04-01

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

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

    PubMed

    Oshima, Hiraku; Kinoshita, Masahiro

    2015-04-14

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

  14. Solvent-Ion Interactions in Salt Water: A Simple Experiment.

    ERIC Educational Resources Information Center

    Willey, Joan D.

    1984-01-01

    Describes a procedurally quick, simple, and inexpensive experiment which illustrates the magnitude and some effects of solvent-ion interactions in aqueous solutions. Theoretical information, procedures, and examples of temperature, volume and hydration number calculations are provided. (JN)

  15. Neurotoxic effects of solvent exposure on sewage treatment workers

    SciTech Connect

    Kraut, A.; Lilis, R.; Marcus, M.; Valciukas, J.A.; Wolff, M.S.; Landrigan, P.J.

    1988-07-01

    Nineteen Sewage Treatment Workers (STWs) exposed to industrial sewage that contained benzene, toluene, and other organic solvents at a primary sewage treatment plant in New York City (Plant A) were examined for evidence of solvent toxicity. Fourteen (74%) complained of central nervous system (CNS) symptoms consistent with solvent exposure, including lightheadedness, fatigue, increased sleep requirement, and headache. The majority of these symptoms resolved with transfer from the plant. Men working less than 1 yr at Plant A were more likely to complain of two or more CNS symptoms than men who were working there longer than 1 yr (p = .055). Objective abnormalities in neurobehavioral testing were found in all 4 men working longer than 9 yr at this plant, but in only 5 of 15 employed there for a shorter period (p = .03). These results are consistent with the known effects of solvent exposure. Occupational health personnel must be aware that STWs can be exposed to solvents and other industrial wastes.

  16. DESIGNING ENVIRONMENTALLY BENIGN SOLVENT SUBSTITUTES

    EPA Science Inventory

    Since the signing of 1987 Montreal Protocol, reducing and eliminating the use of harmful solvents has become an internationally imminent environmental protection mission. Solvent substitution is an effective way to achieve this goal. The Program for Assisting the Replacement of...

  17. Solvent dewaxing of lubricating oils

    SciTech Connect

    Sequeira, A. Jr.

    1991-04-09

    This paper describes improvement in a process for producing a dewaxed lubricating oil from a wax-bearing mineral oil by the steps comprising; mixing the oil with a dewaxing solvent thereby forming an oil-solvent mixture, chilling the oil-solvent mixture to a dewaxing temperature thereby crystallizing the wax and forming an oil-solvent crystalline wax mixture, separating the oil-solvent-crystalline wax mixture to form a dewaxed oil-solvent mixture and crystalline wax, steam stripping the dewaxed oil-solvent mixture at a temperature of 300{degrees}F to 600{degrees}F and pressure of 1 atm to 3 atm, to yield a solvent free dewaxed oil.

  18. Solvent substitution for electronic products

    SciTech Connect

    Benkovich, M.K.

    1992-01-01

    Allied-Signal Inc., Kansas City Division (KCD), manufactures the electrical, electrochemical, mechanical, and plastic components for nuclear weapons. The KCD has made a commitment to eliminate the use of chlorohydrocarbon (CHC) and chlorofluorocarbon (CFC) solvents to the greatest technical extent possible consistent with nuclear safety and stockpile reliability requirements. Current cleaning processes in the production departments use trichloroethylene, 1,1,1-trichloroethane, and various CFC-113 based solvents. Several non-halogenated solvents (Solvent A - an aqueous solvent based on N,N-dimethylacetamide, Solvent B - an aqueous mixture of ethanol amines, Solvent C - a hydrocarbon solvent based on octadecyl acetate, Solvent D - a terpene (d-limonene) hydrocarbon solvent combined with emulsifiers, Solvent E - a terpene (d-limonene) hydrocarbon solvent combined with a separation agent, d-limonene, and isopropyl alcohol) were evaluated to determine the most effective, non-chlorinated, non-fluorinated, alternate solvent cleaning system. All of these solvents were evaluated using current manual spray cleaning processes. The solvents were evaluated for their effectiveness in removing a rosin based RMA solder flux, a particular silicone mold release, and oils, greases, mold releases, resins, etc. The Meseran Surface Analyzer was used to measure organic contamination on the samples before and after cleaning. An Omega Meter Model 600 was also used to detect solder flux residues. Solvents C, D, E and d-limonene the best alternatives to trichloroethylene for removing all of the contaminants tested. For this particular electronic assembly, d-limonene was chosen as the alternate because of material compatibility and long-term reliability concerns.

  19. Green Solvents for Precision Cleaning

    NASA Technical Reports Server (NTRS)

    Grandelli, Heather; Maloney, Phillip; DeVor, Robert; Surma, Jan; Hintze, Paul

    2013-01-01

    Aerospace machinery used in liquid oxygen (LOX) fuel systems must be precision cleaned to achieve a very low level of non-volatile residue (< 1 mg0.1 m2), especially flammable residue. Traditionally chlorofluorocarbons (CFCs) have been used in the precision cleaning of LOX systems, specifically CFC 113 (C2Cl3F3). CFCs have been known to cause the depletion of ozone and in 1987, were banned by the Montreal Protocol due to health, safety and environmental concerns. This has now led to the development of new processes in the precision cleaning of aerospace components. An ideal solvent-replacement is non-flammable, environmentally benign, non-corrosive, inexpensive, effective and evaporates completely, leaving no residue. Highlighted is a green precision cleaning process, which is contaminant removal using supercritical carbon dioxide as the environmentally benign solvent. In this process, the contaminant is dissolved in carbon dioxide, and the parts are recovered at the end of the cleaning process completely dry and ready for use. Typical contaminants of aerospace components include hydrocarbon greases, hydraulic fluids, silicone fluids and greases, fluorocarbon fluids and greases and fingerprint oil. Metallic aerospace components range from small nuts and bolts to much larger parts, such as butterfly valves 18 in diameter. A fluorinated grease, Krytox, is investigated as a model contaminant in these preliminary studies, and aluminum coupons are employed as a model aerospace component. Preliminary studies are presented in which the experimental parameters are optimized for removal of Krytox from aluminum coupons in a stirred-batch process. The experimental conditions investigated are temperature, pressure, exposure time and impeller speed. Temperatures of 308 - 423 K, pressures in the range of 8.3 - 41.4 MPa, exposure times between 5 - 60 min and impeller speeds of 0 - 1000 rpm were investigated. Preliminary results showed up to 86 cleaning efficiency with the

  20. PARIS II: DESIGNING GREENER SOLVENTS

    EPA Science Inventory

    PARIS II (the program for assisting the replacement of industrial solvents, version II), developed at the USEPA, is a unique software tool that can be used for customizing the design of replacement solvents and for the formulation of new solvents. This program helps users avoid ...

  1. Hazardous solvent substitution

    SciTech Connect

    Twitchell, K.E.

    1995-11-01

    Eliminating hazardous solvents is good for the environment, worker safety, and the bottom line. However, even though we are motivated to find replacements, the big question is `What can we use as replacements for hazardous solvents?`You, too, can find replacements for your hazardous solvents. All you have to do is search for them. Search through the vendor literature of hundreds of companies with thousands of products. Ponder the associated material safety data sheets, assuming of course that you can obtain them and, having obtained them, that you can read them. You will want to search the trade magazines and other sources for product reviews. You will want to talk to users about how well the product actually works. You may also want to check US Environmental Protection Agency (EPA) and other government reports for toxicity and other safety information. And, of course, you will want to compare the product`s constituent chemicals with the many hazardous constituency lists to ensure the safe and legal use of the product in your workplace.

  2. Molecular accessibility in solvent swelled coal. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1992-11-01

    To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were later confirmed by magnetic resonance imaging at Argonne National Lab and the University of Illinois.

  3. Solvent replacement for green processing.

    PubMed Central

    Sherman, J; Chin, B; Huibers, P D; Garcia-Valls, R; Hatton, T A

    1998-01-01

    The implementation of the Montreal Protocol, the Clean Air Act, and the Pollution Prevention Act of 1990 has resulted in increased awareness of organic solvent use in chemical processing. The advances made in the search to find "green" replacements for traditional solvents are reviewed, with reference to solvent alternatives for cleaning, coatings, and chemical reaction and separation processes. The development of solvent databases and computational methods that aid in the selection and/or design of feasible or optimal environmentally benign solvent alternatives for specific applications is also discussed. Images Figure 2 Figure 3 PMID:9539018

  4. SOLVENT FIRE BY-PRODUCTS

    SciTech Connect

    Walker, D; Samuel Fink, S

    2006-05-22

    Southwest Research Institute (SwRI) conducted a burn test of the Caustic-Side Solvent Extraction (CSSX) solvent to determine the combustion products. The testing showed hydrogen fluoride gas is not a combustion product from a solvent fire when up to 70% of the solvent is consumed. The absence of HF in the combustion gases may reflect concentration of the modifier containing the fluoride groups in the unburned portion. SwRI reported results for other gases (CO, HCN, NOx, formaldehyde, and hydrocarbons). The results, with other supporting information, can be used for evaluating the consequences of a facility fire involving the CSSX solvent inventory.

  5. Effects of Solvent Composition on the Assembly and Relaxation of Triblock Copolymer-Based Polyelectrolyte Gels

    SciTech Connect

    Henderson, Kevin J.; Shull, Kenneth R.

    2012-03-26

    The role of solvent selectivity has been explored extensively with regard to its role in the phase behavior of block copolymer assemblies. Traditionally, thermally induced phase separation is employed for generating micelles upon cooling a block copolymer dissolved in a selective solvent. However few amphiphilic, polyelectrolyte-containing block copolymers demonstrate a thermally accessible route of micellization, and solvent exchange routes are frequently employed instead. Here, we describe the use of mixed solvents for obtaining thermoreversible gelation behavior of poly(methyl methacrylate)-poly(methacrylic acid)-poly(methyl methacrylate) (PMMA-PMAA-PMMA) triblock copolymers. One solvent component (dimethyl sulfoxide) is a good solvent for both blocks, and the second solvent component (water) is a selective solvent for the polymer midblock. Rheological frequency sweeps at variable solvent compositions and temperatures demonstrate an adherence to time-temperature-composition superposition, so that changes in the solvent composition are analogous to changes in the Flory-Huggins interaction parameter between end block and solvent. Shift factors used for this superposition are related to the effective activation energy describing the viscosity and stress relaxation response of the triblock copolymer gels. The effectiveness of solvent exchange processes for producing hydrogels with this system is shown to originate from the ability of a small amount of added water to greatly increase the relaxation times of the self-assembled polymer gels that are formed by this process.

  6. Qualitative and quantitative evaluation of solvent systems for countercurrent separation.

    PubMed

    Friesen, J Brent; Ahmed, Sana; Pauli, Guido F

    2015-01-16

    Rational solvent system selection for countercurrent chromatography and centrifugal partition chromatography technology (collectively known as countercurrent separation) studies continues to be a scientific challenge as the fundamental questions of comparing polarity range and selectivity within a solvent system family and between putative orthogonal solvent systems remain unanswered. The current emphasis on metabolomic investigations and analysis of complex mixtures necessitates the use of successive orthogonal countercurrent separation (CS) steps as part of complex fractionation protocols. Addressing the broad range of metabolite polarities demands development of new CS solvent systems with appropriate composition, polarity (π), selectivity (σ), and suitability. In this study, a mixture of twenty commercially available natural products, called the GUESSmix, was utilized to evaluate both solvent system polarity and selectively characteristics. Comparisons of GUESSmix analyte partition coefficient (K) values give rise to a measure of solvent system polarity range called the GUESSmix polarity index (GUPI). Solvatochromic dye and electrical permittivity measurements were also evaluated in quantitatively assessing solvent system polarity. The relative selectivity of solvent systems were evaluated with the GUESSmix by calculating the pairwise resolution (αip), the number of analytes found in the sweet spot (Nsw), and the pairwise resolution of those sweet spot analytes (αsw). The combination of these parameters allowed for both intra- and inter-family comparison of solvent system selectivity. Finally, 2-dimensional reciprocal shifted symmetry plots (ReSS(2)) were created to visually compare both the polarities and selectivities of solvent system pairs. This study helps to pave the way to the development of new solvent systems that are amenable to successive orthogonal CS protocols employed in metabolomic studies. PMID:25542704

  7. Occupational solvent exposure and cognition

    PubMed Central

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

    2012-01-01

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

  8. GPU/CPU Algorithm for Generalized Born/Solvent-Accessible Surface Area Implicit Solvent Calculations.

    PubMed

    Tanner, David E; Phillips, James C; Schulten, Klaus

    2012-07-10

    Molecular dynamics methodologies comprise a vital research tool for structural biology. Molecular dynamics has benefited from technological advances in computing, such as multi-core CPUs and graphics processing units (GPUs), but harnessing the full power of hybrid GPU/CPU computers remains difficult. The generalized Born/solvent-accessible surface area implicit solvent model (GB/SA) stands to benefit from hybrid GPU/CPU computers, employing the GPU for the GB calculation and the CPU for the SA calculation. Here, we explore the computational challenges facing GB/SA calculations on hybrid GPU/CPU computers and demonstrate how NAMD, a parallel molecular dynamics program, is able to efficiently utilize GPUs and CPUs simultaneously for fast GB/SA simulations. The hybrid computation principles demonstrated here are generally applicable to parallel applications employing hybrid GPU/CPU calculations.

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

    DOEpatents

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

    2007-03-27

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

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

    DOEpatents

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

    2004-06-22

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

  11. Hazardous solvent source reduction

    SciTech Connect

    Callahan, M.S.; Green, B.

    1995-09-01

    This book is written for the managers, production leaders, and operations staff tasked with the job of eliminating hazardous cleaning solvents from their workplace. Information regarding the location, evaluation, and implementation of environmentally preferred cleaning technologies is offered for a broad range of applications. These include: removal of grease and grime from a piece of equipment during maintenance, cleaning small parts before assembly, defluxing printed circuit boards and assemblies, and stripping paint from field vehicles and aircraft. Moving beyond the limits of source reduction alone, this book provides complete information on the planning, staffing, and execution of a pollution prevention program, alternative and in-use cleaner testing, waste recycling and treatment, air emission control, replacement system design, and system economics. For the environmental specialist, this book helps to bridge the gap between regulatory requirements and shop-floor constraints.

  12. Computational polymer physics: Hard-sphere chain in solvent systems

    NASA Astrophysics Data System (ADS)

    Gautam, Avinash; Gavazzi, Daniel; Taylor, Mark

    2009-10-01

    In this work we present results for chain conformation in two simple chain-in-solvent systems constructed from hard-sphere monomers of diameter D. The first system consists of a flexible chain of fused hard spheres (i.e., bond length L=D) in a monomeric hard-sphere solvent. The second system consists of a flexible tangent hard-sphere chain (L=D) in a dimeric hard-sphere solvent with L=D. These systems are studied using Monte Carlo simulations which employ both single-site crankshaft and multi-site pivot moves to sample the configuration space of the chain. We report chain structure, in terms of site-site probability functions, as a function of solvent density. In all cases, increasing solvent density leads to an overall compression of the chain. At high solvent density the chain conformation is closely coupled to the local solvent structure and we speculate that incommensurate structures may lead to interesting conformational transitions.

  13. Evaluating Employability Skills: Employer and Student Perceptions

    ERIC Educational Resources Information Center

    Saunders, Venetia; Zuzel, Katherine

    2010-01-01

    Graduate employability is a key issue for Higher Education. In this two-part study student employability skills have been evaluated from the perspective of sandwich students and graduates in biomolecular science, and their employers. A strong correlation was found between employer and sandwich student/graduate perceptions of the relative…

  14. Enzymes from solvent-tolerant microbes: useful biocatalysts for non-aqueous enzymology.

    PubMed

    Gupta, Anshu; Khare, S K

    2009-01-01

    Solvent-tolerant microbes are a newly emerging class that possesses the unique ability to thrive in the presence of organic solvents. Their enzymes adapted to mediate cellular and metabolic processes in a solvent-rich environment and are logically stable in the presence of organic solvents. Enzyme catalysis in non-aqueous/low-water media is finding increasing applications for the synthesis of industrially important products, namely peptides, esters, and other trans-esterification products. Solvent stability, however, remains a prerequisite for employing enzymes in non-aqueous systems. Enzymes, in general, get inactivated or give very low rates of reaction in non-aqueous media. Thus, early efforts, and even some recent ones, have aimed at stabilization of enzymes in organic media by immobilization, surface modifications, mutagenesis, and protein engineering. Enzymes from solvent-tolerant microbes appear to be the choicest source for studying solvent-stable enzymes because of their unique ability to survive in the presence of a range of organic solvents. These bacteria circumvent the solvent's toxic effects by virtue of various adaptations, e.g. at the level of the cytoplasmic membrane, by degradation and transformation of solvents, and by active excretion of solvents. The recent screening of these exotic microbes has generated some naturally solvent-stable proteases, lipases, cholesterol oxidase, cholesterol esterase, cyclodextrin glucanotransferase, and other important enzymes. The unique properties of these novel biocatalysts have great potential for applications in non-aqueous enzymology for a range of industrial processes.

  15. SOLVENT EXTRACTION OF URANIUM VALUES

    DOEpatents

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

    1959-02-01

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

  16. Supercritical multicomponent solvent coal extraction

    NASA Technical Reports Server (NTRS)

    Corcoran, W. H.; Fong, W. S.; Pichaichanarong, P.; Chan, P. C. F.; Lawson, D. D. (Inventor)

    1983-01-01

    The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.

  17. Solvent changeouts without plant shutdown

    SciTech Connect

    Vickery, D.J.; Campbell, S.W. )

    1988-01-01

    For reasons of greater selectivity, lower regeneration energy requirements, reduced corrosivity and possible greater amine stability, MDEA continues to replace DEA in numerous selective H/sub 2/S removal applications. Solvent changeouts from DEA to MDEA often require no equipment modification, yet they are generally achieved by shutting down the plant, draining the old solvent, cleaning, and finally recharging with MDEA. However, in at least one plant, solvent changeout was done on the fly simply by periodically making up normal DEA losses with MDEA until the plant was finally operating on MDEA alone. Gradual solvent changeouts have the advantages of no lost production, no disposal problems with the environmentally-hazardous old solvent, no use and subsequent disposal of cleaning agents, and no additional manpower requirements. An advanced flowsheet simulation capability can suggest when such a procedure is feasible and, when it is, plant simulation can help to ensure that the solvent changeout is done reliably and with no production or cost penalties. GASPLANT-PLUS(TM) is currently the only commercial simulator having formulated solvent (mixed amine) capabilities within a fully flexible flowsheeting environment. After highlighting its technical foundations, they will compare GASPLANT-PLUS predictions with some commercial plant data and, through examples, they will show how solvent changeouts can be done gradually, without plant shutdown.

  18. Solvent degradation products in nuclear fuel processing solvents

    SciTech Connect

    Shook, H.E. Jr.

    1988-06-01

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

  19. Solubility of drugs in aqueous solutions. Part 2: binary nonideal mixed solvent.

    PubMed

    Ruckenstein, E; Shulgin, I

    2003-07-24

    As in a previous paper [Int. J. Pharm. 258 (2003) 193-201], the Kirkwood-Buff theory of solutions was employed to calculate the solubility of a solid in mixed solvents. Whereas in the former paper the binary solvent was assumed ideal, in the present one it was considered nonideal. A rigorous expression for the activity coefficient of a solute at infinite dilution in a mixed solvent [Int. J. Pharm. 258 (2003) 193-201] was used to obtain an equation for the solubility of a poorly soluble solid in a nonideal mixed solvent in terms of the solubilities of the solute in the individual solvents, the molar volumes of those solvents, and the activity coefficients of the components of the mixed solvent. The Flory-Huggins and Wilson equations for the activity coefficients of the components of the mixed solvent were employed to correlate 32 experimental data sets regarding the solubility of drugs in aqueous mixed solvents. The results were compared with the models available in literature. It was found that the suggested equation can be used for an accurate and reliable correlation of the solubilities of drugs in aqueous mixed binary solvents. It provided slightly better results than the best literature models but has also the advantage of a theoretical basis.

  20. COMPUTER AIDED SOLVENT DESIGN FOR THE ENVIRONMENT

    EPA Science Inventory

    Solvent substitution is an effective and useful means of eliminating the use of harmful solvents, but finding substitute solvents which are less harmful and as effective as currently used solvents presents significant difficulties. Solvent substitution is a form of reverse engin...

  1. Epilepsy and employment--employers' attitudes.

    PubMed

    Cooper, M

    1995-09-01

    The aim of this study was to examine the possible causes of employment difficulties amongst people with epilepsy by interviewing employers. It was hoped that the outcome of the study would complement the research already carried out in this field by concentrating on the attitudes and policies of employers. Due to the time limit it was decided that a small number (five) of local employers should be approached requesting an interview. The employers were randomly selected but were all large companies within varying industries. All employers approached agreed to participate in the study and interviews were arranged with welfare recruitment staff. The interviews were limited to 45 minutes and concentrated on three main issues for discussion: disclosure, unemployment and improved relationship between employers and people with epilepsy. The outcome of the interviews was that the employers appeared to be rather unaware of the employment problems faced by people with epilepsy. As epilepsy is generally not a registered disability employers are unable to monitor their company's recruitment and promotion methods. It seems that line managers are left to decide on the employment of people with epilepsy often without even general awareness training on equal opportunities. Consequently their need to meet targets and their personal attitude to epilepsy determine the employment chances for people with epilepsy. Only with legislations protecting the interests of people with epilepsy can the unemployment figures be brought in line with the general population.

  2. Solvent-free and catalyst-free chemistry: A benign pathway to sustainability

    EPA Science Inventory

    In the past decade, alternative benign organic methodologies have become an imperative part of organic syntheses and novel chemical reactions. The various new and innovative sustainable organic reactions and methodologies using no solvents or catalysts and employing alternative ...

  3. EXPERIENCES IN DESIGNING SOLVENTS FOR THE ENVIRONMENT

    EPA Science Inventory

    To meet the great need of replacing many harmful solvents commonly used by industry and the public with environmentally benign substitute solvents, the PARIS II solvent design software has been developed. Although the difficulty of successfully finding replacements increases with...

  4. Swelling of lignites in organic solvents

    SciTech Connect

    R.G. Makitra; D.V. Bryk

    2008-10-15

    Data on the swelling of Turkish lignites can be summarized using linear multiparameter equations that take into account various properties of solvents. Factors responsible for the amounts of absorbed solvents are the basicity and cohesion energy density of the solvents.

  5. Acetone-based cellulose solvent.

    PubMed

    Kostag, Marc; Liebert, Tim; Heinze, Thomas

    2014-08-01

    Acetone containing tetraalkylammonium chloride is found to be an efficient solvent for cellulose. The addition of an amount of 10 mol% (based on acetone) of well-soluble salt triethyloctylammonium chloride (Et3 OctN Cl) adjusts the solvent's properties (increases the polarity) to promote cellulose dissolution. Cellulose solutions in acetone/Et3 OctN Cl have the lowest viscosity reported for comparable aprotic solutions making it a promising system for shaping processes and homogeneous chemical modification of the biopolymer. Recovery of the polymer and recycling of the solvent components can be easily achieved.

  6. Caustic-Side Solvent Extraction Solvent-Composition Recommendation

    SciTech Connect

    Klatt, L.N.

    2002-05-09

    The U.S. Department of Energy has selected caustic-side solvent extraction as the preferred cesium removal technology for the treatment of high-level waste stored at the Savannah River Site. Data for the solubility of the extractant, calix[4]arene-bis(tert-octyl benzo-crown-6), acquired and reported for the Salt Processing Program down-select decision, showed the original solvent composition to be supersaturated with respect to the extractant. Although solvent samples have been observed for approximately 1 year without any solids formation, work was completed to define a new solvent composition that was thermodynamically stable with respect to solids formation and to expand the operating temperature with respect to third-phase formation. Chemical and physical data as a function of solvent component concentrations were collected. The data included calix[4]arene-bis(tert-octyl benzo-crown-6) solubility; cesium distribution ratio under extraction, scrub, and strip conditions; flow sheet robustness; temperature range of third-phase formation; dispersion numbers for the solvent against waste simulant, scrub and strip acids, and sodium hydroxide wash solutions; solvent density; viscosity; and surface and interfacial tension. These data were mapped against a set of predefined performance criteria. The composition of 0.007 M calix[4]arene-bis(tert-octyl benzo-crown-6), 0.75 M 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol, and 0.003 M tri-n-octylamine in the diluent Isopar{reg_sign} L provided the best match between the measured properties and the performance criteria. Therefore, it is recommended as the new baseline solvent composition.

  7. Solvent-controlled intramolecular [2 + 2] photocycloadditions of alpha-substituted enones.

    PubMed

    Ng, Stephanie M; Bader, Scott J; Snapper, Marc L

    2006-06-01

    The regio- and stereoselectivity of intramolecular [2 + 2] photocycloadditions of 2'-hydroxyenones are shown to be solvent-dependent. In the presence of aprotic solvents, 2'-hydroxyenones undergo photocycloadditions in a manner consistent with the presence of an intramolecular hydrogen bond between the carbonyl group and the tether's hydroxy functionality. In protic solvents, intermolecular interactions appear to disrupt the intramolecular hydrogen bond, providing products with complementary diastereoselectivity. If the facial accessibility of the alpha-tethered olefin is limited, the cycloadditions proceed to give head-to-tail or head-to-head regioisomers, depending on the nature of the solvent employed.

  8. Preparing Youth for Employment.

    ERIC Educational Resources Information Center

    Bishop, John

    A four-year study examined the nature and policy implications of school and employer practices to help youth prepare for employment. Data for the study were compiled from a telephone survey of 3,500 employers; a mail survey of 750 employers from across the country; 493 employers, 71 teachers, and 1,565 students from 5 major U.S. cities who…

  9. SOLV-DB: Solvents Data

    DOE Data Explorer

    SOLV-DB provides a specialized mix of information on commercially available solvents. The development of the database was funded under the Strategic Environmental Research and Development Program (SERDP) with funds from EPA and DOE's Office of Industrial Technologies in EE. The information includes: • Health and safety considerations involved in choosing and using solvents • Chemical and physical data affecting the suitability of a particular solvent for a wide range of potential applications • Regulatory responsibilities, including exposure and effluent limits, hazard classification status with respect to several key statutes, and selected reporting requirements • Environmental fate data, to indicate whether a solvent is likely to break down or persist in air or water, and what types of waste treatment techniques may apply to it • CAS numbers (from Chemical Abstracts Service) and Sax Numbers (from Sax, et.al., Dangerous Properties of Industrial Materials) Supplier Information See help information at http://solvdb.ncms.org/welcome.htm (Specialized Interface)

  10. ON-SITE SOLVENT RECOVERY

    EPA Science Inventory

    This study evaluated the product quality, waste reduction/pollution prevention, and economic aspects of three technologies for onsite solvent recovery: atmospheric batch distillation, vacuum heat-pump distillation, and low-emission vapor degreasing. The atmospheric and vacuum ...

  11. Control of solvent evaporation in hen egg white lysozyme crystallization

    NASA Astrophysics Data System (ADS)

    Wilson, L. J.; Suddath, F. L.

    1992-02-01

    An investigation of the role of solvent evaporation in tetragonal lysozyme crystallization was preformed with a device that employs N 2(g) to control the evaporation of solvent from a micro-volume crystallization hanging drop. The number of crystals was found to vary with the rate at which the final supersaturation level was achieved. It was found that the more rapid the approach to supersaturation the larger the number of crystals. Accordingly, the crystals reached a smaller terminal size. Elongation of the (110) face parallel to the four-fold axis was observed with the slower evaporation rates.

  12. Control of solvent evaporation in hen egg white lysozyme crystallization

    NASA Technical Reports Server (NTRS)

    Wilson, L. J.; Suddath, F. L.

    1992-01-01

    An investigation of the role of solvent evaporation in tetragonal lysozyme crystallization was preformed with a device that employs N2(g) to control the evaporation of solvent from a micro-volume crystallization hanging drop. The number of crystals was found to vary with the rate at which the final supersaturation level was achieved. It was found that the more rapid the approach to supersaturation the larger the number of crystals. Accordingly, the crystals reached a smaller terminal size. Elongation of the (110) face parallel to the four-fold axis was observed with the slower evaporation rates.

  13. Solvent effect on the vibrational spectrum of Michler's ketone. Experimental and theoretical investigations

    NASA Astrophysics Data System (ADS)

    Sowula, Marta; Misiaszek, Tomasz; Bartkowiak, Wojciech

    2014-10-01

    We examined solvent effect on the IR and Raman spectra of MK in several solvents of different polarity and proticity, for understanding of intermolecular interactions, focusing on solvent effect in detail. It has been found that change of solvent polarity has an ambiguous influence on solvatochromism of MK. We have observed that not only vibrations of carbonyl group are affected by the solvent polarity, but also mode ν(Csbnd N) and ν(Csbnd C) in IR and Raman spectra of MK. Experimental investigations have been supported by the quantum-mechanical computations to gain more insight into the solvatochromic behavior of Michler's ketone. Calculations have been carried using Kohn-Sham formulation of Density Functional Theory (DFT) and the Polarizable Continuum Model (PCM) was employed to account for solute solvent interactions.

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  15. Computational comparison of oxidation stability: Solvent/salt monomers vs solvent-solvent/salt pairs

    NASA Astrophysics Data System (ADS)

    Kim, Dong Young; Park, Min Sik; Lim, Younhee; Kang, Yoon-Sok; Park, Jin-Hwan; Doo, Seok-Gwang

    2015-08-01

    A fundamental understanding of the anodic stabilities of electrolytes is important for the development of advanced high-voltage electrolytes. In this study, we calculated and systematically compared the oxidation stabilities of monomeric solvents and anions, and bimolecular solvent-solvent and anion-solvent systems that are considered to be high-voltage electrolyte components, using ab initio calculations. Oxidation stabilities of solvent or anion monomers without considering specific solvation molecules cannot represent experimental oxidation stabilities. The oxidation of electrolytes usually forms neutral or cationic radicals, which immediately undergo further reactions stabilizing the products. Oxidatively driven intermolecular reactions are the main reason for the lower oxidation stabilities of electrolytes compared with those of monomeric compounds. Electrolyte components such as tetramethylene sulfone (TMS), ethyl methyl sulfone (EMS), bis(oxalate)borate (BOB-), and bis(trifluoromethane)sulfonamide (TFSI-) that minimize such intermolecular chemical reactions on oxidation can maintain the oxidation stabilities of monomers. In predictions of the theoretical oxidation stabilities of electrolytes, simple comparisons of highest occupied molecular orbital energies can be misleading, even if microsolvation or bulk clusters are considered. Instead, bimolecular solvent complexes with a salt anion should be at least considered in oxidation calculations. This study provides important information on fundamental and applied aspects of the development of electrolytes.

  16. Employing Discourse: Universities and Graduate "Employability"

    ERIC Educational Resources Information Center

    Boden, Rebecca; Nedeva, Maria

    2010-01-01

    What constitutes graduate employability is discursively framed. In this paper we argue that whilst universities in the UK have long had an involvement in producing useful and productive citizens, the ongoing neoliberalisation of higher education has engendered a discursive shift in definitions of employability. Traditionally, universities regarded…

  17. Employers' Views on Youth Literacy and Employability

    ERIC Educational Resources Information Center

    Macey, Emma

    2013-01-01

    This report looks at whether employers think schools are equipping young people with the literacy skills required for the workplace. It is primarily based on secondary literature sources and introductory conversations with a small sample of key employers and agencies. A complementary report presents evidence on young people's views on literacy and…

  18. Employer's Manual on Affirmative Action in Employment.

    ERIC Educational Resources Information Center

    Kentucky State Commission on Human Rights, Frankfort.

    The express purpose of this manual is for its use by business and industry in Kentucky as an aid to eliminate discrimination. Affirmative action is defined here as a comprehensive effort by an employer designed to: employ women and minority persons where they are under-utilized; include minority persons and women in all facets of the company's…

  19. Illegal Aliens: Their Employment and Employers.

    ERIC Educational Resources Information Center

    Chiswick, Barry R.

    A study examined various characteristics of the employment of illegal aliens, including wages, job training, job mobility, workplace conditions, and employer characteristics. The study was largely based on data transcribed from a sample of Immigration and Naturalization Service apprehension reports on illegal aliens in the Chicago (Illinois)…

  20. Solvent viscosity dependence for enzymatic reactions

    NASA Astrophysics Data System (ADS)

    Sitnitsky, A. E.

    2008-09-01

    A mechanism for relationship of solvent viscosity with reaction rate constant at enzyme action is suggested. It is based on fluctuations of electric field in enzyme active site produced by thermally equilibrium rocking (crankshaft motion) of the rigid plane (in which the dipole moment ≈3.6 D lies) of a favourably located and oriented peptide group (or may be a few of them). Thus the rocking of the plane leads to fluctuations of the electric field of the dipole moment. These fluctuations can interact with the reaction coordinate because the latter in its turn has transition dipole moment due to separation of charges at movement of the reacting system along it. The rocking of the plane of the peptide group is sensitive to the microviscosity of its environment in protein interior and the latter is a function of the solvent viscosity. Thus we obtain an additional factor of interrelationship for these characteristics with the reaction rate constant. We argue that due to the properties of the crankshaft motion the frequency spectrum of the electric field fluctuations has a sharp resonance peak at some frequency and the corresponding Fourier mode can be approximated as oscillations. We employ a known result from the theory of thermally activated escape with periodic driving to obtain the reaction rate constant and argue that it yields reliable description of the pre-exponent where the dependence on solvent viscosity manifests itself. The suggested mechanism is shown to grasp the main feature of this dependence known from the experiment and satisfactorily yields the upper limit of the fractional index of a power in it.

  1. Coal liquefaction process with enhanced process solvent

    DOEpatents

    Givens, Edwin N.; Kang, Dohee

    1984-01-01

    In an improved coal liquefaction process, including a critical solvent deashing stage, high value product recovery is improved and enhanced process-derived solvent is provided by recycling second separator underflow in the critical solvent deashing stage to the coal slurry mix, for inclusion in the process solvent pool.

  2. Acid Base Titrations in Nonaqueous Solvents and Solvent Mixtures

    NASA Astrophysics Data System (ADS)

    Barcza, Lajos; Buvári-Barcza, Ágnes

    2003-07-01

    The acid base determination of different substances by nonaqueous titrations is highly preferred in pharmaceutical analyses since the method is quantitative, exact, and reproducible. The modern interpretation of the reactions in nonaqueous solvents started in the last century, but several inconsistencies and unsolved problems can be found in the literature. The acid base theories of Brønsted Lowry and Lewis as well as the so-called solvent theory are outlined first, then the promoting (and leveling) and the differentiating effects are discussed on the basis of the hydrogen-bond concept. Emphasis is put on the properties of formic acid and acetic anhydride since their importance is increasing.

  3. Learning, Labour and Employability

    ERIC Educational Resources Information Center

    Ball, Malcolm J.

    2009-01-01

    Public policy in the UK has adopted employability to define the relationship of globalisation, work and learning. This article claims that employability serves the interests of capital. It helps capital to exercise its domination/hegemony over labour and employs a redefined vision of learning as its principal vehicle. Employability is a term that…

  4. DOE solvent handbook information sheet

    SciTech Connect

    Chavez, A.A.

    1992-01-01

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

  5. DOE solvent handbook information sheet

    SciTech Connect

    Chavez, A.A.

    1992-05-01

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

  6. Biodegradation and toxicity to fish of di-long-chain tertiary amine salt containing ester and amide bonds.

    PubMed

    Toshima, Y; Katoh, T; Nishiyama, N; Tsugukuni, T; Saito, F

    1994-10-01

    Biodegradability of N-(3-alkanoylaminopropyl)-N-(2-alkanoyloxyethyl)-N- methylammonium chloride (EAA) was investigated. Biodegradabilities by biochemical oxygen demand (BOD) and dissolved organic carbon (DOC) after 28 days were 79 and 91%, respectively, and almost the same amount of ammonium ion as the theoretical value was detected using a modified MITI test (I) (OECD guidelines, 301C). In the test with activated sludge obtained from a municipal sewage treatment plant, biodegradabilities by BOD and DOC after 35 days were 87 and 98%, respectively, and the 1H-NMR analysis of the tested solution which was done separately under similar conditions indicated the rise and fall of two biodegradation intermediates. Therefore, EEA was considered to be a readily and ultimately biodegradable compound. Besides, the 96-hr LC50 value in red killifish (Oryzias latipes) of EAA was 66 mg/liter. More than 1000 mg/liter was of biodegradation intermediates rapidly made by biodegradation of EAA. These results reveal that EAA has sufficient environmental compatibility. PMID:7529158

  7. Microbore liquid chromatography of tertiary amine anticholinergic pharmaceuticals with tris(2,2'-bipyridine)ruthenium(III) chemiluminescence detection.

    PubMed

    Holeman, J A; Danielson, N D

    1995-06-01

    The post-column chemiluminescent reaction of six anticholinergic alkaloid compounds with tris(2,2'-bipyridine)ruthenium(III) (Ru(bpy)3(3+)) is applied to microbore high-performance liquid chromatography (HPLC). At flow rates less than 200 microL/min, the capillary mixing cell in which Ru(bpy)3(3+) and the analyte are mixed directly allows for good light detection. In contrast, a diminished signal occurs at these low flow rates with conventional post-column mixing in a tee. Optimal chemiluminescent pH conditions for atropine, scopolamine, dicyclomine, cyclopentolate, cyclobenzaprine, and procyclidine are determined at moderately basic conditions (pH 7 to 9). 2-Butanone is found to be compatible with the chemiluminescent reaction, whereas tetrahydrofuran and propionitrile cause an increase in background noise and a chemiluminescent signal loss. As 2-butanone is more nonpolar than acetonitrile, it assists in the elution of these hydrophobic anticholinergic compounds. Five anticholinergic compounds are resolved successfully with a PRP-1 polymeric column and a slightly basic mobile phase, but a C8 silica column is better suited for the more hydrophobic compounds (cyclobenzaprine, procyclidine, and dicyclomine).

  8. Copper(II)-catalyzed oxidative N-nitrosation of secondary and tertiary amines with nitromethane under an oxygen atmosphere.

    PubMed

    Sakai, Norio; Sasaki, Minoru; Ogiwara, Yohei

    2015-07-25

    The combination of a catalytic amount of Cu(OTf)2 and less than a stoichiometric amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under an O2 atmosphere effectively promoted the N-nitrosation of both secondary aromatic/aliphatic amines and tertiary aromatic amines with nitromethane (CH3NO2) leading to the preparation of N-nitrosamine derivatives.

  9. Solvent reorganization of electron transitions in viscous solvents

    SciTech Connect

    Ghorai, Pradip K.; Matyushov, Dmitry V.

    2006-04-14

    We develop a model of electron transfer reactions at conditions of nonergodicity when the time of solvent relaxation crosses the observation time window set up by the reaction rate. Solvent reorganization energy of intramolecular electron transfer in a charge-transfer molecule dissolved in water and acetonitrile is studied by molecular dynamics simulations at varying temperatures. We observe a sharp decrease of the reorganization energy at a temperature identified as the temperature of structural arrest due to cage effect, as discussed by the mode-coupling theory. This temperature also marks the onset of the enhancement of translational diffusion relative to rotational relaxation signaling the breakdown of the Stokes-Einstein relation. The change in the reorganization energy at the transition temperature reflects the dynamical arrest of the slow, collective relaxation of the solvent related to the relaxation of the solvent dipolar polarization. An analytical theory proposed to describe this effect agrees well with both the simulations and experimental Stokes shift data. The theory is applied to the analysis of charge-transfer kinetics in a low-temperature glass former. We show that the reorganization energy is substantially lower than its equilibrium value for the low-temperature portion of the data. The theory predicts the possibility of discontinuous changes in the dependence of the electron transfer rate on the free energy gap when the reaction switches between ergodic and nonergodic regimes.

  10. Organic Solvent Effects in Biomass Conversion Reactions.

    PubMed

    Shuai, Li; Luterbacher, Jeremy

    2016-01-01

    Transforming lignocellulosic biomass into fuels and chemicals has been intensely studied in recent years. A large amount of work has been dedicated to finding suitable solvent systems, which can improve the transformation of biomass into value-added chemicals. These efforts have been undertaken based on numerous research results that have shown that organic solvents can improve both conversion and selectivity of biomass to platform molecules. We present an overview of these organic solvent effects, which are harnessed in biomass conversion processes, including conversion of biomass to sugars, conversion of sugars to furanic compounds, and production of lignin monomers. A special emphasis is placed on comparing the solvent effects on conversion and product selectivity in water with those in organic solvents while discussing the origins of the differences that arise. We have categorized results as benefiting from two major types of effects: solvent effects on solubility of biomass components including cellulose and lignin and solvent effects on chemical thermodynamics including those affecting reactants, intermediates, products, and/or catalysts. Finally, the challenges of using organic solvents in industrial processes are discussed from the perspective of solvent cost, solvent stability, and solvent safety. We suggest that a holistic view of solvent effects, the mechanistic elucidation of these effects, and the careful consideration of the challenges associated with solvent use could assist researchers in choosing and designing improved solvent systems for targeted biomass conversion processes.

  11. Organic Solvent Effects in Biomass Conversion Reactions.

    PubMed

    Shuai, Li; Luterbacher, Jeremy

    2016-01-01

    Transforming lignocellulosic biomass into fuels and chemicals has been intensely studied in recent years. A large amount of work has been dedicated to finding suitable solvent systems, which can improve the transformation of biomass into value-added chemicals. These efforts have been undertaken based on numerous research results that have shown that organic solvents can improve both conversion and selectivity of biomass to platform molecules. We present an overview of these organic solvent effects, which are harnessed in biomass conversion processes, including conversion of biomass to sugars, conversion of sugars to furanic compounds, and production of lignin monomers. A special emphasis is placed on comparing the solvent effects on conversion and product selectivity in water with those in organic solvents while discussing the origins of the differences that arise. We have categorized results as benefiting from two major types of effects: solvent effects on solubility of biomass components including cellulose and lignin and solvent effects on chemical thermodynamics including those affecting reactants, intermediates, products, and/or catalysts. Finally, the challenges of using organic solvents in industrial processes are discussed from the perspective of solvent cost, solvent stability, and solvent safety. We suggest that a holistic view of solvent effects, the mechanistic elucidation of these effects, and the careful consideration of the challenges associated with solvent use could assist researchers in choosing and designing improved solvent systems for targeted biomass conversion processes. PMID:26676907

  12. Which solvent for olfactory testing?

    PubMed

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

    2004-12-01

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

  13. Replacement solvents for use in chemical synthesis

    DOEpatents

    Molnar, Linda K.; Hatton, T. Alan; Buchwald, Stephen L.

    2001-05-15

    Replacement solvents for use in chemical synthesis include polymer-immobilized solvents having a flexible polymer backbone and a plurality of pendant groups attached onto the polymer backbone, the pendant groups comprising a flexible linking unit bound to the polymer backbone and to a terminal solvating moiety. The polymer-immobilized solvent may be dissolved in a benign medium. Replacement solvents for chemical reactions for which tetrahydrofuran or diethyl may be a solvent include substituted tetrahydrofurfuryl ethers and substituted tetrahydro-3-furan ethers. The replacement solvents may be readily recovered from the reaction train using conventional methods.

  14. Graduate Identity and Employability

    ERIC Educational Resources Information Center

    Hinchliffe, Geoffrey William; Jolly, Adrienne

    2011-01-01

    This paper develops the concept of graduate identity as a way of deepening the understanding of graduate employability. It does this through presenting research in which over 100 employers in East Anglia were asked to record their perceptions of graduates in respect of their employability. The findings suggest a composite and complex graduate…

  15. Recognition for Employed Inventors.

    ERIC Educational Resources Information Center

    Sanders, Howard J.

    1980-01-01

    Presents arguments for monetary rewards and other forms of recognition by employers for inventions of employed inventors, particularly as the concept applies to stimulating innovativeness in America. Discusses the controversy of federally mandated compensation for employed inventors. The efforts of the American Chemical Society along these lines…

  16. The New Employment Contract?

    ERIC Educational Resources Information Center

    Levine, David I.

    2002-01-01

    In the classic employment contract, especially at large companies, wages were not strongly responsive to the labor market. Instead, individual companies had distinctive company wage levels and patterns. An exhaustive study of employers and employees in the United States and Japan examined whether the "old employment contract" has been replaced.…

  17. A generic analysis of energy use and solvent selection for CO2 separation from post-combustion flue gases

    USGS Publications Warehouse

    Lu, Y.; Chen, S.; Rostam-Abadi, M.

    2008-01-01

    A thermodynamic calculation was performed to determine the theoretical minimum energy used to separate CO2 from a coal combustion flue gas in a typical adsorption-desorption system. Under ideal conditions, the minimum energy required to separate CO2 from post-combustion flue gas and produce pure CO2 at 1 atmospheric pressure was only about 1183 kJ/kg CO2. This amount could double with the addition of the driving forces of mass and heat transfer and the adverse impacts of absorption heat release on adsorption capacity. Thermodynamic analyses were also performed for the aqueous amine-based absorption process. Two CO2 reaction mechanisms, the carbamate formation reaction with primary/secondary amines and the CO2 hydration reaction with tertiary amines, were included in the absorption reaction. The reaction heat, sensible heat, and stripping heat were all important to the total heat requirement. The heat use of an ideal tertiary amine amounted to 2786 kJ/kg, compared to 3211 kJ/kg for an ideal primary amine. The heat usage of an ideal amine was about 20% lower than that of commercially available amines. Optimizing the absorption process configuration could further reduce energy use. This is an abstract of a paper presented at the 2008 AIChE Spring National Meeting (New Orleans, LA 4/6-10/2008).

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

    ERIC Educational Resources Information Center

    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…

  19. Employer-employee relations.

    PubMed

    Copeland, J D

    1993-09-01

    As an employer, a veterinarian must be vigilant to protect the rights of both job applicants and employees. Federal and state statutes guarantee that applicants and employees will not be subjected to discrimination in any aspect of employment, including recruitment, hiring, promotion, compensation, and termination of employment. An employer may not discriminate on the basis of sex, race, color, national origin, religion, age, or physical disability. In addition, common law tort actions give employees powerful causes of action be against those employers who injure employees. More than ever, employers must be diligent in obeying the law. Employers must also take measures to protect themselves from employee claims by instituting risk management plans and purchasing adequate insurance coverage.

  20. Dipolar correlations in structured solvents under nanoconfinement

    NASA Astrophysics Data System (ADS)

    Buyukdagli, Sahin; Blossey, Ralf

    2014-06-01

    We study electrostatic correlations in structured solvents confined to nanoscale systems. We derive variational equations of Netz-Orland type for a model liquid composed of finite size dipoles. These equations are solved for both dilute solvents and solvents at physiological concentrations in a slit nanopore geometry. Correlation effects are of major importance for the dielectric reduction and anisotropy of the solvent resulting from dipole image interactions and also lead to a reduction of van der Waals attractions between low dielectric bodies. Finally, by comparison with other recently developed self-consistent theories and experiments, we scrutinize the effect of solvent-membrane interactions on the differential capacitance of the charged liquid in contact with low dielectric substrates. The interfacial solvent depletion driven by solvent-image interactions plays the major role in the observed low values of the experimental capacitance data, while non-locality associated with the extended charge structure of solvent molecules only brings a minor contribution.

  1. Dipolar correlations in structured solvents under nanoconfinement.

    PubMed

    Buyukdagli, Sahin; Blossey, Ralf

    2014-06-21

    We study electrostatic correlations in structured solvents confined to nanoscale systems. We derive variational equations of Netz-Orland type for a model liquid composed of finite size dipoles. These equations are solved for both dilute solvents and solvents at physiological concentrations in a slit nanopore geometry. Correlation effects are of major importance for the dielectric reduction and anisotropy of the solvent resulting from dipole image interactions and also lead to a reduction of van der Waals attractions between low dielectric bodies. Finally, by comparison with other recently developed self-consistent theories and experiments, we scrutinize the effect of solvent-membrane interactions on the differential capacitance of the charged liquid in contact with low dielectric substrates. The interfacial solvent depletion driven by solvent-image interactions plays the major role in the observed low values of the experimental capacitance data, while non-locality associated with the extended charge structure of solvent molecules only brings a minor contribution. PMID:24952564

  2. Dipolar correlations in structured solvents under nanoconfinement.

    PubMed

    Buyukdagli, Sahin; Blossey, Ralf

    2014-06-21

    We study electrostatic correlations in structured solvents confined to nanoscale systems. We derive variational equations of Netz-Orland type for a model liquid composed of finite size dipoles. These equations are solved for both dilute solvents and solvents at physiological concentrations in a slit nanopore geometry. Correlation effects are of major importance for the dielectric reduction and anisotropy of the solvent resulting from dipole image interactions and also lead to a reduction of van der Waals attractions between low dielectric bodies. Finally, by comparison with other recently developed self-consistent theories and experiments, we scrutinize the effect of solvent-membrane interactions on the differential capacitance of the charged liquid in contact with low dielectric substrates. The interfacial solvent depletion driven by solvent-image interactions plays the major role in the observed low values of the experimental capacitance data, while non-locality associated with the extended charge structure of solvent molecules only brings a minor contribution.

  3. The extraction of aromatic amino acids with binary and ternary mixtures of hydrophilic solvents

    NASA Astrophysics Data System (ADS)

    Mokshina, N. Ya.; Pakhomova, O. A.; Niftaliev, S. I.

    2007-11-01

    The extraction of tyrosine and phenylalanine with binary and ternary mixtures of hydrophilic solvents from aqueous salt solutions was studied, and several tendencies were observed. Simplex-lattice planning of experiment was used for the optimization of the composition of solvent mixtures. It was shown that the extraction systems developed could be employed for the almost complete extraction of tyrosine and phenylalanine from aqueous solutions.

  4. The solvent component of macromolecular crystals

    SciTech Connect

    Weichenberger, Christian X.; Kantardjieff, Katherine; Rupp, Bernhard

    2015-04-30

    On average, the mother liquor or solvent and its constituents occupy about 50% of a macromolecular crystal. Ordered as well as disordered solvent components need to be accurately accounted for in modelling and refinement, often with considerable complexity. The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.

  5. Solvent Extraction of Furfural From Biomass

    NASA Technical Reports Server (NTRS)

    Humphrey, M. F.

    1984-01-01

    Solvent-extraction method reduces energy required to remove furfural produced during acid hydrolysis of biomass. Acid hydrolysis performed in vessel containing both solvents and reacting ingredients. With intimate contact between solvents and aqueous hydrolyis liqour, furfural removed form liquor almost as fast as it forms.

  6. The hype with ionic liquids as solvents

    NASA Astrophysics Data System (ADS)

    Kunz, Werner; Häckl, Katharina

    2016-09-01

    In this mini review, we give our personal opinion about the present state of the art concerning Ionic Liquids, proposed as alternative solvents. In particular, we consider their different drawbacks and disadvantages and discuss the critical aspects of the research of Ionic Liquids as solvents. Finally, we point out some aspects on potentially promising Ionic Liquid solvents.

  7. Firing of pulverized solvent refined coal

    DOEpatents

    Derbidge, T. Craig; Mulholland, James A.; Foster, Edward P.

    1986-01-01

    An air-purged burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired without the coking thereof on the burner components. The air-purged burner is designed for the firing of pulverized solvent refined coal in a tangentially fired boiler.

  8. Assessment of solvent effects: do weak alignment media affect the structure of the solute?

    PubMed

    Shahkhatuni, Astghik A; Shahkhatuni, Aleksan G; Panosyan, Henry A; Sahakyan, Aleksandr B; Byeon, In-Ja L; Gronenborn, Angela M

    2007-07-01

    Alignment media used for measuring residual dipolar couplings, such as solutions of filamentous phages, phospholipid mixtures, polyacrylamide gels and various lyotropic liquid crystalline systems were investigated with respect to solvent effects on molecular structure. Structural parameters of the small rigid model compound 13C-acetonitrile were calculated from dipolar couplings and variations from expectation values were used for assessment of solvent effects. Only minor solvent effects were observed for most of the media employed and the measured structural data are in good agreement with microwave data and theoretical predictions. PMID:17534883

  9. Inducing surface morphologies in polymer films through exposure to non-solvents

    NASA Astrophysics Data System (ADS)

    Daley, Chad; Tun, Zin; Forrest, James

    2014-03-01

    Non-solvents are generally considered to have no lasting effect on polymer materials and are commonly employed in the production or processing of thin film polymer samples. Through a combination of atomic force microscopy and neutron reflectivity experiments we show that some non-solvents have the ability to drastically alter a film's surface morphology on the nanometer scale. An explanation for the structuring process is presented and reinforced through theoretical considerations of surface chains. These results suggest that caution should be exercised when making use of non-solvents wherever nanoscale surface properties are of importance.

  10. Solvent effects and alkali metal ion catalysis in phosphodiester hydrolysis.

    PubMed

    Gomez-Tagle, Paola; Vargas-Zúñiga, Idania; Taran, Olga; Yatsimirsky, Anatoly K

    2006-12-22

    The kinetics of the alkaline hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) have been studied in aqueous DMSO, dioxane, and MeCN. In all solvent mixtures the reaction rate steadily decreases to half of its value in pure water in the range of 0-70 vol % of organic cosolvent and sharply increases in mixtures with lower water content. Correlations based on different scales of solvent empirical parameters failed to describe the solvent effect in this system, but it can be satisfactorily treated in terms of a simplified stepwise solvent-exchange model. Alkali metal ions catalyze the BNPP hydrolysis but do not affect the rate of hydrolysis of neutral phosphotriester p-nitrophenyl diphenyl phosphate in DMSO-rich mixtures. The catalytic activity decreases in the order Li+ > Na+ > K+ > Rb+ > Cs+. For all cations except Na+, the reaction rate is first-order in metal ion. With Na+, both first- and second-order kinetics in metal ions are observed. Binding constants of cations to the dianionic transition state of BNPP alkaline hydrolysis are of the same order of magnitude and show a similar trend as their binding constants to p-nitrophenyl phosphate dianion employed as a transition-state model. The appearance of alkali metal ion catalysis in a medium, which solvates metal ions stronger than water, is attributed to the increased affinity of cations to dianions, which undergo a strong destabilization in the presence of an aprotic dipolar cosolvent.

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

    DOEpatents

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

    2009-01-06

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

  12. Solute-solvent and solvent-solvent interactions in the preferential solvation of 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide in 24 binary solvent mixtures

    NASA Astrophysics Data System (ADS)

    Bevilaqua, Tharly; Gonçalves, Thaini F.; Venturini, Cristina de G.; Machado, Vanderlei G.

    2006-11-01

    The molar transition energy ( ET) polarity values for the dye 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide were collected in binary mixtures comprising a hydrogen-bond accepting (HBA) solvent (acetone, acetonitrile, dimethyl sulfoxide (DMSO), and N, N-dimethylformamide (DMF)) and a hydrogen-bond donating (HBD) solvent (water, methanol, ethanol, propan-2-ol, and butan-1-ol). Data referring to mixtures of water with alcohols were also analyzed. These data were used in the study of the preferential solvation of the probe, in terms of both solute-solvent and solvent-solvent interactions. These latter interactions are of importance in explaining the synergistic behavior observed for many mixed solvent systems. All data were successfully fitted to a model based on solvent-exchange equilibria. The ET values of the dye dissolved in the solvents show that the position of the solvatochromic absorption band of the dye is dependent on the medium polarity. The solvation of the dye in HBA solvents occurs with a very important contribution from ion-dipole interactions. In HBD solvents, the hydrogen bonding between the dimethylamino group in the dye and the OH group in the solvent plays an important role in the solvation of the dye. The interaction of the hydroxylic solvent with the other component in the mixture can lead to the formation of hydrogen-bonded complexes, which solvate the dye using a lower polar moiety, i.e. alkyl groups in the solvents. The dye has a hydrophobic nature and a dimethylamino group with a minor capability for hydrogen bonding with the medium in comparison with the phenolate group present in Reichardt's pyridiniophenolate. Thus, the probe is able to detect solvent-solvent interactions, which are implicit to the observed synergistic behavior.

  13. Batch extracting process using magneticparticle held solvents

    DOEpatents

    Nunez, Luis; Vandergrift, George F.

    1995-01-01

    A process for selectively removing metal values which may include catalytic values from a mixture containing same, wherein a magnetic particle is contacted with a liquid solvent which selectively dissolves the metal values to absorb the liquid solvent onto the magnetic particle. Thereafter the solvent-containing magnetic particles are contacted with a mixture containing the heavy metal values to transfer metal values into the solvent carried by the magnetic particles, and then magnetically separating the magnetic particles. Ion exchange resins may be used for selective solvents.

  14. Phase behavior and second osmotic virial coefficient for competitive polymer solvation in mixed solvent solutions.

    PubMed

    Dudowicz, Jacek; Freed, Karl F; Douglas, Jack F

    2015-11-21

    We apply our recently developed generalized Flory-Huggins (FH) type theory for the competitive solvation of polymers by two mixed solvents to explain general trends in the variation of phase boundaries and solvent quality (quantified by the second osmotic virial coefficient B2) with solvent composition. The complexity of the theoretically predicted miscibility patterns for these ternary mixtures arises from the competitive association between the polymer and the solvents and from the interplay of these associative interactions with the weak van der Waals interactions between all components of the mixture. The main focus here lies in determining the influence of the free energy parameters for polymer-solvent association (solvation) and the effective FH interaction parameters {χαβ} (driving phase separation) on the phase boundaries (specifically the spinodals), the second osmotic virial coefficient B2, and the relation between the positions of the spinodal curves and the theta temperatures at which B2 vanishes. Our classification of the predicted miscibility patterns is relevant to numerous applications of ternary polymer solutions in industrial formulations and the use of mixed solvent systems for polymer characterization, such as chromatographic separation where mixed solvents are commonly employed. A favorable comparison of B2 with experimental data for poly(methyl methacrylate)/acetonitrile/methanol (or 1-propanol) solutions only partially supports the validity of our theoretical predictions due to the lack of enough experimental data and the neglect of the self and mutual association of the solvents.

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

    SciTech Connect

    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.

  16. Phase behavior and second osmotic virial coefficient for competitive polymer solvation in mixed solvent solutions

    NASA Astrophysics Data System (ADS)

    Dudowicz, Jacek; Freed, Karl F.; Douglas, Jack F.

    2015-11-01

    We apply our recently developed generalized Flory-Huggins (FH) type theory for the competitive solvation of polymers by two mixed solvents to explain general trends in the variation of phase boundaries and solvent quality (quantified by the second osmotic virial coefficient B 2 ) with solvent composition. The complexity of the theoretically predicted miscibility patterns for these ternary mixtures arises from the competitive association between the polymer and the solvents and from the interplay of these associative interactions with the weak van der Waals interactions between all components of the mixture. The main focus here lies in determining the influence of the free energy parameters for polymer-solvent association (solvation) and the effective FH interaction parameters {χαβ} (driving phase separation) on the phase boundaries (specifically the spinodals), the second osmotic virial coefficient B 2 , and the relation between the positions of the spinodal curves and the theta temperatures at which B 2 vanishes. Our classification of the predicted miscibility patterns is relevant to numerous applications of ternary polymer solutions in industrial formulations and the use of mixed solvent systems for polymer characterization, such as chromatographic separation where mixed solvents are commonly employed. A favorable comparison of B 2 with experimental data for poly(methyl methacrylate)/acetonitrile/methanol (or 1-propanol) solutions only partially supports the validity of our theoretical predictions due to the lack of enough experimental data and the neglect of the self and mutual association of the solvents.

  17. Critical Casimir interactions and colloidal self-assembly in near-critical solvents.

    PubMed

    Tasios, Nikos; Edison, John R; van Roij, René; Evans, Robert; Dijkstra, Marjolein

    2016-08-28

    A binary solvent mixture close to critical demixing experiences fluctuations whose correlation length, ξ, diverges as the critical point is approached. The solvent-mediated (SM) interaction that arises between a pair of colloids immersed in such a near-critical solvent can be long-ranged and this so-called critical Casimir interaction is well-studied. How a (dense) suspension of colloids will self-assemble under these conditions is poorly understood. Using a two-dimensional lattice model for the solvent and hard disks to represent the colloids, we perform extensive Monte Carlo simulations to investigate the phase behaviour of this model colloidal suspension as a function of colloid size and wettability under conditions where the solvent reservoir is supercritical. Unlike most other approaches, where the solvent is modelled as an implicit background, our model employs an explicit solvent and treats the suspension as a ternary mixture. This enables us to capture important features, including the pronounced fractionation of the solvent in the coexisting colloidal phases, of this complex system. We also present results for the partial structure factors; these shed light on the critical behaviour in the ternary mixture. The degree to which an effective two-body pair potential description can describe the phase behaviour and structure of the colloidal suspension is discussed briefly. PMID:27586941

  18. Effects of solvent-extraction contactor selection on flowsheet and facility design

    SciTech Connect

    Whatley, M.E.

    1982-01-01

    The notion is developed that the selection of a solvent extraction contactor is part of a more general development of principles and philosophy guiding the overall plant design. Specifically, the requirements and constraints placed on the plant by the solvent extraction system must be consistent with those imposed by the other operations, which generally are more expensive and more complicated. Were a conservative philosophy employed throughout the plant, the choice of pulsed columns seem correct. Were the plant intended to employ modern techniques and state-of-the-art technology, particularly in remote maintenance and process control, the selection of centrifugal contactors seems appropriate. The process improvements attainable from employing more stages in a more tightly controlled solvent extraction system seem marginal at present when applied to conventional flowsheets, although the cost-benefit may be attractive in a modern plant. The potential for improvement through major flowsheet modification can not presently be assessed quantitatively.

  19. Deep eutectic solvents as efficient solvent system for the extraction of κ-carrageenan from Kappaphycus alvarezii.

    PubMed

    Das, Arun Kumar; Sharma, Mukesh; Mondal, Dibyendu; Prasad, Kamalesh

    2016-01-20

    Three different deep eutectic solvents (DESs) prepared by the complexation of choline chloride with urea, ethylene glycol and glycerol along with their hydrated counterparts were used for the selective extraction of κ-carrageenan from Kappaphycus alvarezii. Upon comparison of the quality of the polysaccharide with the one obtained using water as extraction media as well as the one extracted using widely practiced conventional method, it was found that, the physicochemical as well as rheological properties of κ-carrageenan obtained using DESs as solvents was at par to the one obtained using conventional method and was superior in quality when compared to κ-carrageenan obtained using water as solvent. Considering the tedious nature of the extraction method employed in conventional extraction process, the DESs can be considered as suitable alternative solvents for the facile extraction of the polysaccharide directly from the seaweed. However, among the hydrated and non-hydrated DESs, the hydrated ones were found to be more effective in comparison to their non-hydrated counterparts. PMID:26572431

  20. Listening to Employers

    ERIC Educational Resources Information Center

    Machalski, Jan; Riley, Alison; Aubrey, Karl

    2009-01-01

    Various government initiatives have highlighted the importance of employer engagement in schools, further education and higher education. However, speaking as a team of lecturers in HE the authors have found that there is a tension between the perceptions of government and those of employers. Clearly, it would be a good thing if, particularly in…

  1. Discrimination in Employment.

    ERIC Educational Resources Information Center

    Kovarsky, Irving

    Intended as a guide on discrimination problems and issues for students and practitioners in the area of employment relations, this book interrelates historical, religious, economic, medical, and sociological factors surrounding racial, religious, national, sex, age, and physical and mental discrimination to explain discrimination in employment.…

  2. Employment of Children.

    ERIC Educational Resources Information Center

    Bowser, Robert A., Comp.

    This document presents Pennsylvania guidelines for interpreting child labor legislation. In Section I employment certification of minors under the child labor law, the school laws of Pennsylvania, and the federal law are discussed. In Section II the issuing officers responsible for issuing employment certificates are identified, procedures for…

  3. Part-Time Employment.

    ERIC Educational Resources Information Center

    Guichard, Gus; And Others

    The employment of community college instructors on a part-time basis provides the opportunity for students to study under outstanding instructors whose primary employment may be in industry or in other postsecondary institutions and permits colleges to respond better to community needs with the financial resources available to them. Along with…

  4. Does Supported Employment Work?

    ERIC Educational Resources Information Center

    Morgan McInnes, Melayne; Ozturk, Orgul Demet; McDermott, Suzanne; Mann, Joshua R.

    2010-01-01

    Providing employment-related services, including supported employment through job coaches, has been a priority in federal policy since the enactment of the Developmental Disabilities Assistance and Bill of Rights Act in 1984. We take advantage of a unique panel data set of all clients served by the South Carolina Department of Disabilities and…

  5. Employment Discrimination: A Survey.

    ERIC Educational Resources Information Center

    Caplan, Gerald A.

    Chapter 4 in a book on school law provides a general overview of the various federal statutes directed toward discrimination in employment and considers some of the recent developments under these statutes. The first section is a survey of the employment discrimination laws and their interrelationships. The second section analyzes more closely…

  6. Employment Policy and Territories.

    ERIC Educational Resources Information Center

    Berthet, Thierry; Cuntigh, Philippe; Guitton, Christophe

    2002-01-01

    France's employment policy has historically been governed by a strategy of interventions aimed at specific categories of individuals, including victims of industrial restructuring, entry workers, the long-term unemployed, and the disabled. Since the 1980s, France has had the following main lines of employment policy: (1) assistance to victims of…

  7. Supported Employment in Spain.

    ERIC Educational Resources Information Center

    Verdugo, Miguel Angel; Borja, F.; de Urries, Jordan; Bellver, Fernando; Martinez, Salvador

    1998-01-01

    Supported employment is growing in Spain, assisted by models from other countries and national legislation. The Spanish Association of Supported Employment is providing a framework for program development. The field must deal with the lack of systematic evaluation and with funding problems. (SK)

  8. Numeracy and Employment.

    ERIC Educational Resources Information Center

    Parsons, Samantha; Bynner, John

    1997-01-01

    Employment experiences were compared for British adults with good/average literacy and numeracy skills and those with good/average literacy and very low numeracy. Even with good literacy skills, poor numeracy reduced employment and training opportunities and promotion prospects. (SK)

  9. Employment Tax Credit Utilization.

    ERIC Educational Resources Information Center

    Parkinson, Jan

    Utilizing data collected through a national survey of employers, the impact of federal tax credit programs for employers of Work Incentive Program (WIN) participants and Aid to Families with Dependent Children (AFDC) recipients was assessed. Six major questions were addressed: (1) What differences there were in the use of the WIN and welfare tax…

  10. Addressing Employer Services.

    ERIC Educational Resources Information Center

    Perspective: Essays and Reviews of Issues in Employment Security and Employment and Training Programs, 1986

    1986-01-01

    This volume of an annual journal contains 21 articles focusing on the many services that state Employment Security (ES) agencies are providing to improve outreach to employers who pay for the programs through the dedicated revenues of the Federal Unemployment Tax Act and state benefit taxes and to improve their own staff ability to deliver…

  11. Advanced integrated solvent extraction systems

    SciTech Connect

    Horwitz, E.P.; Dietz, M.L.; Leonard, R.A.

    1997-10-01

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

  12. SOLVENT EXTRACTION PROCESS FOR PLUTONIUM

    DOEpatents

    Seaborg, G.T.

    1959-04-14

    The separation of plutonium from aqueous inorganic acid solutions by the use of a water immiscible organic extractant liquid is described. The plutonium must be in the oxidized state, and the solvents covered by the patent include nitromethane, nitroethane, nitropropane, and nitrobenzene. The use of a salting out agents such as ammonium nitrate in the case of an aqueous nitric acid solution is advantageous. After contacting the aqueous solution with the organic extractant, the resulting extract and raffinate phases are separated. The plutonium may be recovered by any suitable method.

  13. [Low-density solvent-based solvent demulsification dispersive liquid-liquid microextraction combined with gas chromatography for determination of polycyclic aromatic hydrocarbons in water samples].

    PubMed

    Zhu, Benqiong; Chen, Hao; Li, Shengqing

    2012-02-01

    A novel method of low-density solvent-based solvent demulsification dispersive liquid-liquid microextraction (SD-DLLME) was developed for the determination of eight polycyclic aromatic hydrocarbons (PAHs) in water samples by gas chromatography-flame ionization detection (GC-FID). Conventional DLLME methods usually employ organic solvents heavier than water as the extraction solvents and achieve the phase separation through centrifugation. On the contrary, in this proposed extraction procedure, a mixture of low-density extraction solvent (toluene) and dispersive solvent (acetone) was injected into the aqueous sample solution to form an emulsion. A demulsification solvent (acetonitrile) was then injected into the aqueous solution to break up the emulsion, which turned clear quickly and was separated into two layers. The upper layer (toluene) was collected and analyzed by GC. No centrifugation was required in this procedure. Factors affecting the extraction efficiency such as the type and volume of dispersive solvent, extraction solvent and de-emulsifier were investigated in detail. Under the optimized conditions, the proposed method provided a good linearity in the range of 20 - 500 microg/L (r2 = 0.994 2 - 0.999 9). The limits of detection (S/N = 3) were in the range of 0.52 - 5.11 microg/L. The relative standard deviations (RSDs) for the determination of 40 microg/L PAHs were in the range of 2.2% - 13.6% (n = 5). The proposed method is fast, efficient and convenient. It has been successfully applied to the determination of PAHs in natural water samples with the spiked recoveries of 80.2% - 115.1%.

  14. Solubility of C60 and PCBM in Organic Solvents.

    PubMed

    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. PMID:26488132

  15. The solvent component of macromolecular crystals

    PubMed Central

    Weichenberger, Christian X.; Afonine, Pavel V.; Kantardjieff, Katherine; Rupp, Bernhard

    2015-01-01

    The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands. PMID:25945568

  16. Placement: The Employer's View.

    ERIC Educational Resources Information Center

    Teff, Donald R.

    1979-01-01

    A bank vice president reviews three barriers to the employment of handicapped persons: misunderstanding and lack of knowledge concerning the handicapped, the traditional lag between recognition of a problem and its solution, and apathy and disinterest. (CL)

  17. Bifunctional anion-exchange resins with improved selectivity and exchange kinetics

    DOEpatents

    Alexandratos, Spiro D.; Brown, Gilbert M.; Bonnesen, Peter V.; Moyer, Bruce A.

    2000-01-01

    Disclosed herein are a class of anion exchange resins containing two different exchange sites with improved selectivity and sorptive capability for chemical species in solution, such as heptavalent technetium (as pertechnetate anion, TcO.sub.4.sup.-). The resins are prepared by first reacting haloalkylated crosslinked copolymer beads with a large tertiary amine in a solvent in which the resin beads can swell, followed by reaction with a second, smaller, tertiary amine to more fully complete the functionalization of the resin. The resins have enhanced selectivity, capacity, and exchange kinetics.

  18. [Chlorinate solvents natural biodegradation in shallow groundwater].

    PubMed

    He, Jiang-tao; Li, Ye; Liu, Shi; Chen, Hong-han

    2005-03-01

    Chlorinated solvents contaminations are most popular in shallow groundwater. A serious local groundwater contamination of chlorinated solvents is founded in a north city of China during the organic pollution investigation. On the basis of the available data and the determining methods of chlorinated solvents biodegradation in groundwater under natural conditions, research on chlorinated solvents biodegrading potential is carried out. The results show that the ground water environment parameters, Eh and pH of the groundwater, indirect sign of biodegradation, i.e. NO3- changing, and concentration variation of biodegradation intermediate products of PCE and TCE all proved that chlorinated solvents can be degraded by microorganism in groundwater. The results of simulating experiment also reveal that, co-metabolism biodegradation of chlorinated solvent was possible under the groundwater circumstances in this sample. Therefore, admitting there is biotransformation from PCE to TCE can explain the present situation more reasonably.

  19. Solvent signal as an NMR concentration reference.

    PubMed

    Mo, Huaping; Raftery, Daniel

    2008-12-15

    We propose that the NMR solvent signal be utilized as a universal concentration reference because most solvents can be observed by NMR and solvent concentrations can be readily calculated or determined independently. In particular, a highly protonated solvent such as water can serve as a primary concentration standard for its stability, availability, and ease of observation. The potential problems of radiation damping associated with a strong NMR signal can be alleviated by small pulse angle excitation. The solvent signal then can be detected by the NMR receiver with the same efficiency as a dilute analyte. We demonstrated that the analyte's proton concentration can be accurately determined from 4 microM to more than 100 M, referenced by solvent (water) protons of concentrations more than 10 M. The proposed method is robust and indifferent to probe tuning and does not require any additional concentration standard.

  20. The solvent dependent shift of the amide I band of a fully solvated peptide in methanol/water mixtures as a local probe for the solvent composition in the peptide/solvent interface

    SciTech Connect

    Gnanakaran, S

    2008-01-01

    We determine the shift and line-shape of the amide I band of a model AK-peptide from molecular dynamics (MD) simulations of the peptide dissolved in methanol/water mixtures with varying composition. The IR-spectra are determined from a transition dipole coupling exciton model. A simplified empirical model Hamiltonian is employed, taking both the effect of hydrogen bonding, as well as intramolecular vibrational coupling into account. We consider a single isolated AK-peptide in a mostly helical conformation, while the solvent is represented by 2600 methanol or water molecules, simulated for a pressure of 1 bar and a temperature of 300 K. Over the course of the simulations minor reversible conformational changes at the termini are observed, which are found to only slightly affect the calculated spectral properties. Over the entire composition range, varying from pure water to the pure methanol solvent, a monotonous blue-shift of the IR amide I band of about 8 wavenumbers is observed. The shift is found to be caused by two counter-compensating effects: An intramolecular red-shift of about 1.2 wavenumbers, due to stronger intramolecular hydrogen-bonding in a methanol-rich environment. Dominating, however, is the intermolecular solvent-dependent blue-shift of about 10 wavenumbers, being attributed to the less effective hydrogen bond donor capabilities of methanol compared to water. The importance of solvent-contribution to the IR-shift, as well as the significantly different hydrogen formation capabilities of water and methanol make the amide I band sensitive to composition changes in the local environment close the peptide/solvent interface. This allows, in principle, an experimental determination of the composition of the solvent in close proximity to the peptide surface. For the AK-peptide case they observe at low methanol concentrations a significantly enhanced methanol concentration at the peptide/solvent-interface, supposedly promoted by the partially hydrophobic

  1. Aryne Compatible Solvents are not Always Innocent.

    PubMed

    Suh, Sung-Eun; Chenoweth, David M

    2016-08-19

    Arynes are important and versatile intermediates in a variety of transformations. Commonly used solvents for aryne chemistry include acetonitrile and dichloromethane. Although rarely reported, the reactive nature of aryne intermediates makes them prone to side reactions, which sometimes involve solvent participation. Acetonitrile and dichloromethane are not always innocent solvents and can participate in aryne-based reactions. These results are presented in the context of ongoing mechanistic investigations of the triple aryne-tetrazine reaction. PMID:27486792

  2. Solvent recovery system provides timely compliance solution

    SciTech Connect

    1996-11-01

    Hoechst Celanese Corp. (Coventry, Rhode Island) faced the challenge of meeting an Environmental Protection Agency (EPA) deadline for solvent recovery within one year. The company also had to ensure that a new solvent recovery system would satisfy Rhode Island state requirements. An initial search for the required technology was fruitless. Finally, MG Industries (Saint Charles, Missouri), an industrial gas supplier, was chosen for the job. Using CRYOSOLV, as the waste stream cools in the cryogenic condenser (heat exchanger), the solvents condense at temperatures below the dewpoint. The recovered solvent can be recycled into the process, while clean gas is vented to the atmosphere.

  3. Process for hydrogenating coal and coal solvents

    DOEpatents

    Tarrer, Arthur R.; Shridharani, Ketan G.

    1983-01-01

    A novel process is described for the hydrogenation of coal by the hydrogenation of a solvent for the coal in which the hydrogenation of the coal solvent is conducted in the presence of a solvent hydrogenation catalyst of increased activity, wherein the hydrogenation catalyst is produced by reacting ferric oxide with hydrogen sulfide at a temperature range of 260.degree. C. to 315.degree. C. in an inert atmosphere to produce an iron sulfide hydrogenation catalyst for the solvent. Optimally, the reaction temperature is 275.degree. C. Alternately, the reaction can be conducted in a hydrogen atmosphere at 350.degree. C.

  4. MCU MATERIALS COMPATIBILITY WITH CSSX SOLVENT

    SciTech Connect

    Fondeur, F

    2006-01-13

    The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) plans to use several new materials of construction not previously used with CSSX solvent. SRNL researchers tested seven materials proposed for service in seal and gasket applications. None of the materials leached detectable amounts of components into the CSSX solvent during 96 hour tests. All are judged acceptable for use based on their effect on the solvent. However, some of the materials adsorbed solvent or changed dimensions during contact with solvent. Consultation with component and material vendors with regard to performance impact and in-use testing of the materials is recommended. Polyetheretherketone (PEEK), a material selected for use in contactor bearing seals, did not gain weight or change dimensions on contact with CSSX solvent. Analysis of the solvent contacted with this material showed no impurities and the standard dispersion test gave acceptable phase separation results. The material contains a leachable hydrocarbon substance, detectable on exposed surfaces, that did not adversely contaminate the solvent within the limits of the testing. We recommend contacting the vendor to determine the source and purpose of this component, or, alternatively, pursue the infrared analysis of the PEEK in an effort to better define potential impacts.

  5. Prediction of the solubility in lipidic solvent mixture: Investigation of the modeling approach and thermodynamic analysis of solubility.

    PubMed

    Patel, Shruti V; Patel, Sarsvatkumar

    2015-09-18

    Self-micro emulsifying drug delivery system (SMEDDS) is one of the methods to improve solubility and bioavailability of poorly soluble drug(s). The knowledge of the solubility of pharmaceuticals in pure lipidic solvents and solvent mixtures is crucial for designing the SMEDDS of poorly soluble drug substances. Since, experiments are very time consuming, a model, which allows for solubility predictions in solvent mixtures based on less experimental data is desirable for efficiency. Solvents employed were Labrafil® M1944CS and Labrasol® as lipidic solvents; Capryol-90®, Capryol-PGMC® and Tween®-80 as surfactants; Transcutol® and PEG-400 as co-solvents. Solubilities of both drugs were determined in single solvent systems at temperature (T) range of 283-333K. In present study, we investigated the applicability of the thermodynamic model to understand the solubility behavior of drugs in the lipiodic solvents. By using the Van't Hoff and general solubility theory, the thermodynamic functions like Gibbs free energy, enthalpy and entropy of solution, mixing and solvation for drug in single and mixed solvents were understood. The thermodynamic parameters were understood in the framework of drug-solvent interaction based on their chemical similarity and dissimilarity. Clotrimazole and Fluconazole were used as active ingredients whose solubility was measured in single solvent as a function of temperature and the data obtained were used to derive mathematical models which can predict solubility in multi-component solvent mixtures. Model dependent parameters for each drug were calculated at each temperature. The experimental solubility data of solute in mixed solvent system were measured experimentally and further correlated with the calculates values obtained from exponent model and log-linear model of Yalkowsky. The good correlation was observed between experimental solubility and predicted solubility.

  6. Solvent-free mechanochemical glycosylation in ball mill.

    PubMed

    Tyagi, Mohit; Khurana, Darpan; Kartha, K P Ravindranathan

    2013-09-20

    Starting from acetobromosugars and an alcohol (alkyl/substituted alkyl/akenyl/alkynyl/glyceryl/cyclohexyl/steryl) various O-glycosides have been prepared mechanochemically under solvent-free conditions employing a planetary ball mill in the presence of metal carbonates (environmentally benign or otherwise) as promoters. The method was proven to be mild and efficient and applicable on preparative scale for the synthesis of various mono- and disaccharide glycosides. 4-Pentenyl glycoside so produced could, in four successive reactions in the same pot, be converted in high isolated yields into triazole-substituted pentyl glycoside that can find application in the area of medicinal chemistry.

  7. The use of carrier solvents in regulatory aquatic toxicology testing: practical, statistical and regulatory considerations.

    PubMed

    Green, John; Wheeler, James R

    2013-11-15

    Solvents are often used to aid test item preparation in aquatic ecotoxicity experiments. This paper discusses the practical, statistical and regulatory considerations. The selection of the appropriate control (if a solvent is used) for statistical analysis is investigated using a database of 141 responses (endpoints) from 71 experiments. The advantages and disadvantages of basing the statistical analysis of treatment effects to the water control alone, solvent control alone, combined controls, or a conditional strategy of combining controls, when not statistically significantly different, are tested. The latter two approaches are shown to have distinct advantages. It is recommended that this approach continue to be the standard used for regulatory and research aquatic ecotoxicology studies. However, wherever technically feasible a solvent should not be employed or at least the concentration minimized.

  8. Morphological investigation of midblock-sulfonated block ionomers prepared from solvents differing in polarity.

    PubMed

    Mineart, Kenneth P; Jiang, Xi; Jinnai, Hiroshi; Takahara, Atsushi; Spontak, Richard J

    2015-03-01

    Recent developments regarding charged multiblock copolymers that can form physical networks and exhibit robust mechanical properties herald new and exciting opportunities for contemporary technologies requiring amphiphilic attributes. Due to the presence of strong interactions, however, control over the phase behavior of such materials remains challenging, especially since their morphologies can be solvent-templated. In this study, transmission electron microscopy and microtomography are employed to examine the morphological characteristics of midblock-sulfonated pentablock ionomers prepared from solvents differing in polarity. Resultant images confirm that discrete, spherical ion-rich microdomains form in films cast from a relatively nonpolar solvent, whereas an apparently mixed morphology with a continuous ion-rich pathway is generated when the casting solvent is more highly polar. Detailed 3D analysis of the morphological characteristics confirms the coexistence of hexagonally-packed nonpolar cylinders and lamellae, which facilitates the diffusion of ions and/or other polar species through the nanostructured medium.

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

    DOEpatents

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

    2002-01-01

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

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

    DOEpatents

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

    2006-07-11

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

  11. Single polymer chains in poor solvent: Using the bond fluctuation method with explicit solvent

    NASA Astrophysics Data System (ADS)

    Jentzsch, Christoph; Werner, Marco; Sommer, Jens-Uwe

    2013-03-01

    We use the bond fluctuation model with explicit solvent to study single polymer chains under poor solvent conditions. Static and dynamic properties of the bond fluctuation model with explicit solvent are compared with the implicit solvent model, and the Θ-temperatures are determined for both solvent models. We show that even in the very poor solvent regime, dynamics is not frozen for the explicit solvent model. We investigate some aspects of the structure of a single collapsed globule and show that rather large chain lengths are necessary to reach the scaling regime of a dense sphere. The force-extension curve of a single polymer chain under poor solvent conditions in the fixed end-to-end distance ensemble is analyzed. We find that the transition of the tadpole conformation to the stretched chain conformation is rather smooth because of fluctuation effects, which is in agreement with recent experimental results.

  12. Wide electrochemical window solvents for use in electrochemical devices and electrolyte solutions incorporating such solvents

    DOEpatents

    Angell, Charles Austen; Zhang, Sheng-Shui; Xu, Kang

    1998-01-01

    The present invention relates to electrolyte solvents for use in liquid or rubbery electrolyte solutions. Specifically, this invention is directed to boron-containing electrolyte solvents and boron-containing electrolyte solutions.

  13. Explicit solvent simulations of the aqueous oxidation potential and reorganization energy for neutral molecules: gas phase, linear solvent response, and non-linear response contributions.

    PubMed

    Guerard, Jennifer J; Tentscher, Peter R; Seijo, Marianne; Samuel Arey, J

    2015-06-14

    First principles simulations were used to predict aqueous one-electron oxidation potentials (Eox) and associated half-cell reorganization energies (λaq) for aniline, phenol, methoxybenzene, imidazole, and dimethylsulfide. We employed quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations of the oxidized and reduced species in an explicit aqueous solvent, followed by EOM-IP-CCSD computations with effective fragment potentials for diabatic energy gaps of solvated clusters, and finally thermodynamic integration of the non-linear solvent response contribution using classical MD. A priori predicted Eox and λaq values exhibit mean absolute errors of 0.17 V and 0.06 eV, respectively, compared to experiment. We also disaggregate Eox into several well-defined free energy properties, including the gas phase adiabatic free energy of ionization (7.73 to 8.82 eV), the solvent-induced shift in the free energy of ionization due to linear solvent response (-2.01 to -2.73 eV), and the contribution from non-linear solvent response (-0.07 to -0.14 eV). The linear solvent response component is further apportioned into contributions from the solvent-induced shift in vertical ionization energy of the reduced species (ΔVIEaq) and the solvent-induced shift in negative vertical electron affinity of the ionized species (ΔNVEAaq). The simulated ΔVIEaq and ΔNVEAaq are found to contribute the principal sources of uncertainty in computational estimates of Eox and λaq. Trends in the magnitudes of disaggregated solvation properties are found to correlate with trends in structural and electronic features of the solute. Finally, conflicting approaches for evaluating the aqueous reorganization energy are contrasted and discussed, and concluding recommendations are given.

  14. Standard test method for nonvolatile residue of volatile cleaning solvents using the solvent purity meter

    SciTech Connect

    Not Available

    1980-01-01

    This method covers the determination of nonvolatile residue of volatile cleaning solvents using a solvent purity meter. The residue is concentrated in aerosol form by evaporation of the more volatile solvents. The volume of the concentrated aerosol is passed by a forward light scattering photometer. Experimentally devised curves relating photometer output to nonvolatile residue concentration are used to obtain parts per million of nonvolatile residue content of the cleaning solvents.

  15. The role of the solvent in PMMA gel polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Vondrák, J.; Musil, M.; Sedlaříková, M.; Kořínek, R.; Bartušek, K.; Fedorková, A.

    2016-03-01

    Ionic mobility and solvent vapor pressure were studied on gels containing sodium perchlorate, polymethylmethacrylate and sulfolane as a solvent. The excess of solvent increases markedly the mobility of ions and is indicated by solvent evaporation at elevated temperature. The solvent is bonded similarly as in the liquid solution of sodium salt. The heat of solvent evaporation from gels is near to that of pure solvents.

  16. Dispersing nanoparticles in a polymer film via solvent evaporation

    DOE PAGES

    Cheng, Shengfeng; Grest, Gary S.

    2016-05-19

    Large-scale molecular dynamics simulations are used to study the dispersion of nanoparticles (NPs) in a polymer film during solvent evaporation. As the solvent evaporates, a dense polymer-rich skin layer forms at the liquid/vapor interface, which is either NP rich or poor depending on the strength of the NP/polymer interaction. When the NPs are strongly wet by the polymer, the NPs accumulate at the interface and form layers. However, when the NPs are only partially wet by the polymer, most NPs are uniformly distributed in the bulk of the polymer film, with the dense skin layer serving as a barrier tomore » prevent the NPs from moving to the interface. Furthermore, our results point to a possible route to employ less favorable NP/polymer interactions and fast solvent evaporation to uniformly disperse NPs in a polymer film, contrary to the common belief that strong NP/polymer attractions are needed to make NPs well dispersed in polymer nanocomposites.« less

  17. 29 CFR 1607.10 - Employment agencies and employment services.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 4 2011-07-01 2011-07-01 false Employment agencies and employment services. 1607.10... agencies and employment services. A. Where selection procedures are devised by agency. An employment agency... employment agency or service is requested to administer a selection procedure which has been...

  18. 29 CFR 1607.10 - Employment agencies and employment services.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Employment agencies and employment services. 1607.10... agencies and employment services. A. Where selection procedures are devised by agency. An employment agency... employment agency or service is requested to administer a selection procedure which has been...

  19. Integration without employment.

    PubMed

    Fink, John N; Libby, Darin E

    2012-08-01

    Three models for hospital-physician alignment may offer hospitals for which large-scale physician employment is not practical the best means to prepare for payment changes under accountable care: Comanagement arrangements Clinical joint ventures Professional services agreements with performance incentives. PMID:22931027

  20. Employer Engagement in Education

    ERIC Educational Resources Information Center

    Mann, Anthony; Dawkins, James

    2014-01-01

    The subject of this paper is employer engagement in education as it supports the learning and progression of young people through activities including work experience, job shadowing, workplace visits, career talks, mock interviews, CV workshops, business mentoring, enterprise competitions and the provision of learning resources. Interest has grown…

  1. Engaging Employers in Assessment

    ERIC Educational Resources Information Center

    Brown, Gary; DesRosier, Theron; Peterson, Nils; Chida, Meriem; Lagier, Randy

    2009-01-01

    In this article, the authors describe a pilot project in which formative feedback from industry professionals creates a genuine learning experience for students. Industry is giving feedback to higher education that many graduates are not employable or that they need substantial postcollegiate on-the-job training. Higher education is struggling to…

  2. Employer Needs Assessment.

    ERIC Educational Resources Information Center

    Shaffer, Richard A.

    In 1990, Cuesta College (CC) conducted a needs assessment of local employers to determine the type of work done by their employees, number of employees, hiring plans, the current level of employee training, and training needs. The mailed survey had 266 usable responses for a 40.9% return rate. Study findings included the following: (1) 31% of the…

  3. Industrialisation, Exports and Employment.

    ERIC Educational Resources Information Center

    Sabolo, Yves

    1980-01-01

    After reviewing trends in industrial production, exports, and employment in the Third World since 1960, the author discusses industrialization strategies based on the local processing of raw materials for export. Such processing has proved to be a major factor in job creation. (Author/SK)

  4. The Employment Mismatch

    ERIC Educational Resources Information Center

    Fischer, Karin

    2013-01-01

    Employers value a four-year college degree, many of them more than ever. Yet half of those surveyed recently by "The Chronicle" and American Public Media's "Marketplace" said they had trouble finding recent graduates qualified to fill positions at their company or organization. Nearly a third gave colleges just fair to poor marks for producing…

  5. Equal Opportunity in Employment

    ERIC Educational Resources Information Center

    Bullock, Paul

    This book focuses on discrimination in employment, defined as the denial of equal opportunity in the labor market to qualified persons on the basis of race, color, religion, national origin, age, sex, or any other factor not related to their individual qualifications for work. The average nonwhite college graduate can expect to earn less during…

  6. Disability Employment 101

    ERIC Educational Resources Information Center

    US Department of Education, 2007

    2007-01-01

    Business is about productivity and maintaining a competitive advantage. To do this, business needs qualified workers. Hiring people with disabilities adds value to a business and will attract new customers. Disability is not inability. Employers can make sound business decisions and gain a competitive advantage by using this guide to increase the…

  7. Gerontology Graduates' Employment Opportunities.

    ERIC Educational Resources Information Center

    Rueb, Suzanne M.; And Others

    1994-01-01

    Of the 66 (of 94) graduates of a Master of Education in Gerontology program, 74% were female and most were white; 63% considered their degree beneficial. Of the 83% employed, 48.5% thought their jobs were highly relevant to the aging field. (SK)

  8. Employer Recruitment & Orientation Guide.

    ERIC Educational Resources Information Center

    Jobs for the Future, Boston, MA.

    Work-based learning is a competency-based experience that integrates classroom instruction with structured work site experiences. Its purpose is to allow students to gain occupational and employable skills while applying and advancing their academic abilities. This guide contains strategies and resources to help educators involve the business…

  9. Technology and employment

    SciTech Connect

    Cooper, M.H.

    1983-07-22

    The influence of technology on today's high unemployment picture is discussed. Employment in the high-technology sector is seen by some to be a panacea for workers who have lost their jobs due to irreversible structural causes. Some federal, regional, state, and local efforts being made to ease structural adjustment are included. 28 references, 2 figures, 3 tables.

  10. Employment of College Students.

    ERIC Educational Resources Information Center

    High, Robert V.

    A survey was conducted to determine the effect on academic performance, if any, of employment on undergraduate college students. A questionnaire was sent to professors at 3 four-year colleges on Long Island (New York); various day classes were randomly selected. The final sample of n=257 represented approximately a 30 percent response. The…

  11. A Stochastic Employment Problem

    ERIC Educational Resources Information Center

    Wu, Teng

    2013-01-01

    The Stochastic Employment Problem(SEP) is a variation of the Stochastic Assignment Problem which analyzes the scenario that one assigns balls into boxes. Balls arrive sequentially with each one having a binary vector X = (X[subscript 1], X[subscript 2],...,X[subscript n]) attached, with the interpretation being that if X[subscript i] = 1 the ball…

  12. Employment. Feature Issue.

    ERIC Educational Resources Information Center

    Wallace, Teri, Ed.; And Others

    1993-01-01

    This theme issue addresses current trends and new developments in ensuring that individuals with disabilities have meaningful employment opportunities, especially in the context of recent federal legislation. Stressed throughout is the importance of collaboration among professionals, individuals with disabilities, and family members in achieving…

  13. Vietnamese Students Employability Skills

    ERIC Educational Resources Information Center

    Tuan, Nguyen Minh

    2011-01-01

    This paper attempts to investigate if the International University (IU) students' core competencies can meet the requirements set by employers, what are the differences in core competencies in final year students (or undergraduates), and how they view themselves compared with ex-students after one or two years in working environment, how…

  14. Should Universities Promote Employability?

    ERIC Educational Resources Information Center

    McCowan, Tristan

    2015-01-01

    Employability is becoming increasingly central to the mission and functioning of universities, spurred on by national and supranational agencies, and the demands of marketisation. This article provides a response to the normative dimensions of the question, progressing through four stages: first, there is a brief consideration of the meaning and…

  15. EXPERIENCES IN DESIGNING SOLVENTS FOR THE ENVIRONMENT

    EPA Science Inventory

    Solvents used throughout industry are chosen to meet specific technological requirements such as solute solubility, cleaning and degreasing, or being a medium for paints and coatings. With the increasing awareness of the human health effects and environmental tisks of solvent use...

  16. EXPERIENCES IN DESIGNING SOLVENTS FOR THE ENVIRONMENT

    EPA Science Inventory

    Solvents used throughout industry are chosen to meet specific technological requirements such as solute solubility, cleaning and degreasing, or being a medium for paints and coatings. With the increasing awareness of the human health effects and environmental risks of solvent use...

  17. Improved Supercritical-Solvent Extraction of Coal

    NASA Technical Reports Server (NTRS)

    Compton, L.

    1982-01-01

    Raw coal upgraded by supercritical-solvent extraction system that uses two materials instead of one. System achieved extraction yields of 20 to 49 weight percent. Single-solvent yields are about 25 weight percent. Experimental results show extraction yields may be timedependent. Observed decreases in weight of coal agreed well with increases in ash content of residue.

  18. Supercritical-Multiple-Solvent Extraction From Coal

    NASA Technical Reports Server (NTRS)

    Corcoran, W.; Fong, W.; Pichaichanarong, P.; Chan, P.; Lawson, D.

    1983-01-01

    Large and small molecules dissolve different constituents. Experimental apparatus used to test supercritical extraction of hydrogen rich compounds from coal in various organic solvents. In decreasing order of importance, relevant process parameters were found to be temperature, solvent type, pressure, and residence time.

  19. SOLVENT-FREE ORGANIC SYNTHESES USING MICROWAVES

    EPA Science Inventory

    The latest results on microwave-expedited solvent-free approach as applied to the assembly of organic molecules will be presented. The salient features of this expeditious methodology such as solvent conservation and ease of manipulation etc. will be described in the context of r...

  20. SOLVENT DESIGN UNDER VARYING ENVIRONMENTAL REQUIREMENTS

    EPA Science Inventory

    There is currently a great need to replace many solvents that are commonly used by industry and the public, but whose continued use entails a number of human health and environmental risks. One issue hampering solvent replacement is the general thought that replacement, particul...

  1. Remediating pesticide contaminated soils using solvent extraction

    SciTech Connect

    Sahle-Demessie, E.; Meckes, M.C.; Richardson, T.L.

    1996-12-31

    Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p{prime}-DDT, p,p{prime}-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as solvents over a wide range of operating conditions. It was demonstrated that a six-stage methanol extraction using a solvent-to-soil ratio of 1.6 can decrease pesticide levels in the soil by more than 99% and reduce the volume of material requiring further treatment by 25 times or more. The high solubility of the pesticides in methanol resulted in rapid extraction rates, with the system reaching quasi-equilibrium state in 30 minutes. The extraction efficiency was influenced by the number of extraction stages, the solvent-to-soil ratio, and the soil moisture content. Various methods were investigated to regenerate and recycle the solvent. Evaporation and solvent stripping are low cost and reliable methods for removing high pesticide concentrations from the solvent. For low concentrations, GAC adsorption may be used. Precipitating and filtering pesticides by adding water to the methanol/pesticide solution was not successful when tested with soil extracts. 26 refs., 10 figs., 6 tabs.

  2. Classification of Solvents according to Interaction Mechanisms.

    ERIC Educational Resources Information Center

    Ahmed, Wasi

    1979-01-01

    Presented is a model for solvent effects based on the observation that the excitation energy of all-trans-N-Retinylidenmethyl-n-butylammonium iodide is directly related to the dielectric constant of a series of aromatic and aliphatic solvents as the dielectric constant (e) ranges from 2 to 10.5. (BT)

  3. REMEDIATING PESTICIDE CONTAMINATED SOILS USING SOLVENT EXTRACTION

    EPA Science Inventory

    Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p'-DDT, p,p'-DDD,, p,p'-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as sol...

  4. Green chemicals: Searching for cleaner solvents

    SciTech Connect

    Lucas, A.

    1994-10-05

    While increased pressure from EPA has solvents producers scrambling to find greener alternatives, many say the cost effectiveness and performance characteristics of traditional technologies are such that they will not disappear quickly. Though a variety of alternative {open_quotes}green{close_quotes} solvents have been developed and commercialized, better means of solvent recovery have also come along, ensuring continued use of many organic solvents. The 1990 Clean Air Act (CAA), designed to eliminate volatile organic compounds (VOCs), ozone depleters, and other hazardous air pollutants (HAPs), has put limits on many organic solvents. Those most under fire are chlorinated solvents, such as methylene chloride, 1,1,1 trichloroethylene (methyl chloroform), and chlorofluorocarbon (CFC)-113. Producers have been developing a variety of lower VOC solvents to replace those being phased out or regulated. Among those likely to experience most growth are aliphatic hydrocarbons to replace chlorinated solvents in cleaning applications. Growth is also expected for alcohols, esters, and glycol ethers for other end-use applications.

  5. REMEDIATION OF CONTAMINATED SOILS BY SOLVENT FLUSHING

    EPA Science Inventory

    Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. This technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, ...

  6. Pneumatic conveying of pulverized solvent refined coal

    DOEpatents

    Lennon, Dennis R.

    1984-11-06

    A method for pneumatically conveying solvent refined coal to a burner under conditions of dilute phase pneumatic flow so as to prevent saltation of the solvent refined coal in the transport line by maintaining the transport fluid velocity above approximately 95 ft/sec.

  7. Gallium complexes and solvent extraction of gallium

    SciTech Connect

    Coleman, J.P.; Graham, C.R.; Monzyk, B.F.

    1988-05-03

    This patent describes a process for recovering gallium from aqueous solutions containing gallium which comprises contacting such a solution with an organic solvent containing at least 2% by weight of a water-insoluble N-organo hydroxamic acid having at least about 8 carbon atoms to extract gallium, and separating the gallium loaded organic solvent phase from the aqueous phase.

  8. Carbon-14 Dating with the Liquid Scintillation Counter: Total Synthesis of the Benzene Solvent.

    PubMed

    Tamers, M A

    1960-09-01

    Samples are analyzed for natural radiocarbon content by a total synthesis of benzene from their organic constituents. The benzene is employed as the solvent in a liquid scintillation counter. The instrument used permits 15grams of carbon to be counted with an efficiency of 40 percent and a background of 13 counts per minute.

  9. TERRA-KLEEN RESPONSE GROUP, INC. SOLVENT EXTRACTION TECHNOLOGY: INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    This report summarizes the results of a field demonstration conducted under the SITE program. The technology which was demonstrated was a solvent extraction technology developed by Terra-Kleen Response Group. Inc. to remove organic contaminants from soil. The technology employs...

  10. Organic solvent regeneration of granular activated carbon

    NASA Astrophysics Data System (ADS)

    Cross, W. H.; Suidan, M. T.; Roller, M. A.; Kim, B. R.; Gould, J. P.

    1982-09-01

    The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to thermal regeneration. The important aspects of the solvent regeneration process include: the physical and chemical characteristics of the adsorbent, the pore size distribution and energy of adsorption associated with the activated carbon; the degree of solubility of the adsorbate in the organic solvent; the miscibility of the organic solvent in water; and the temperature at which the generation is performed.

  11. Toxic hepatitis in occupational exposure to solvents

    PubMed Central

    Malaguarnera, Giulia; Cataudella, Emanuela; Giordano, Maria; Nunnari, Giuseppe; Chisari, Giuseppe; Malaguarnera, Mariano

    2012-01-01

    The liver is the main organ responsible for the metabolism of drugs and toxic chemicals, and so is the primary target organ for many organic solvents. Work activities with hepatotoxins exposures are numerous and, moreover, organic solvents are used in various industrial processes. Organic solvents used in different industrial processes may be associated with hepatotoxicity. Several factors contribute to liver toxicity; among these are: species differences, nutritional condition, genetic factors, interaction with medications in use, alcohol abuse and interaction, and age. This review addresses the mechanisms of hepatotoxicity. The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are: inflammation, dysfunction of cytochrome P450, mitochondrial dysfunction and oxidative stress. The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work. PMID:22719183

  12. SOLVENT DISPERSION AND FLOW METER CALCULATION RESULTS

    SciTech Connect

    Nash, C.; Fondeur, F.; Peters, T.

    2013-06-21

    Savannah River National Laboratory (SRNL) found that the dispersion numbers for the six combinations of CSSX:Next Generation Solvent (NGS) “blend” and pure NGS versus salt solution, caustic wash, and strip aqueous solutions are all good. The dispersion numbers are indications of processability with centrifugal contactors. A comparison of solvent physical and thermal properties shows that the Intek™ solvent flow meter in the plant has a reading biased high versus calibrated flow when NGS is used, versus the standard CSSX solvent. The flow meter, calibrated for CSSX solvent, is predicted to read 2.8 gpm of NGS in a case where the true flow of NGS is 2.16 gpm.

  13. Hydrocarbon-solvent based cleaners as replacements for chlorinated and CFC solvents

    SciTech Connect

    Schreiner, J.L.; Berlin, E.P.

    1995-12-31

    Chlorinated and CFC solvents have been used for about 30 years to remove various contaminants from products during the manufacturing process. Among the contaminants being removed are oils, greases, and waxes that have petroleum products as the base. Prior to the advent of the chlorinated solvents petroleum distillates were used for these cleaning operations. Processing improvements over the past 30 years now permit production of higher purity hydrocarbons solvents that can be used as replacements for the chlorinated and CFC solvents being phased out. These hydrocarbon solvents are well suited for removal of the various petroleum based contaminants, as one recalls the old adage {open_quotes}like dissolves like.{close_quotes}

  14. Overseas Employment: How to Develop Your Own International Employment Service.

    ERIC Educational Resources Information Center

    Klein, Frank

    1985-01-01

    Presents a procedure for developing an International Employment Service for students wanting overseas employment as well as foreign students wanting to work in the United States. Includes information on visas, employment opportunities, and job search methods. (JAC)

  15. Alternative control technology document: Halogenated solvent cleaners. Final report

    SciTech Connect

    Not Available

    1989-08-01

    The document contains information on the use and control of halogenated solvents in solvent-cleaning applications. Described are the types of solvent cleaners manufactured, sources of solvent emissions, methods of controlling solvent emissions, and the costs associated with installation of control devices.

  16. PARIS II: Computer Aided Solvent Design for Pollution Prevention

    EPA Science Inventory

    This product is a summary of U.S. EPA researchers' work developing the solvent substitution software tool PARIS II (Program for Assisting the Replacement of Industrial Solvents, version 2.0). PARIS II finds less toxic solvents or solvent mixtures to replace more toxic solvents co...

  17. Predicting the Solubility of Pharmaceutical Cocrystals in Solvent/Anti-Solvent Mixtures.

    PubMed

    Lange, Linda; Heisel, Stefan; Sadowski, Gabriele

    2016-01-01

    In this work, the solubilities of pharmaceutical cocrystals in solvent/anti-solvent systems were predicted using PC-SAFT in order to increase the efficiency of cocrystal formation processes. Modeling results and experimental data were compared for the cocrystal system nicotinamide/succinic acid (2:1) in the solvent/anti-solvent mixtures ethanol/water, ethanol/acetonitrile and ethanol/ethyl acetate at 298.15 K and in the ethanol/ethyl acetate mixture also at 310.15 K. The solubility of the investigated cocrystal slightly increased when adding small amounts of anti-solvent to the solvent, but drastically decreased for high anti-solvent amounts. Furthermore, the solubilities of nicotinamide, succinic acid and the cocrystal in the considered solvent/anti-solvent mixtures showed strong deviations from ideal-solution behavior. However, by accounting for the thermodynamic non-ideality of the components, PC-SAFT is able to predict the solubilities in all above-mentioned solvent/anti-solvent systems in good agreement with the experimental data. PMID:27164075

  18. AN ACCELERATED RATE CALORIMETRY STUDY OF CAUSTIC-SIDE SOLVENT EXTRACTION SOLVENT WITHOUT EXTRACTANT

    SciTech Connect

    Fondeur, F; Samuel Fink, S

    2006-03-07

    This study found that 4 - 48 part per thousand (ppth) of Caustic Side Solvent Extraction (CSSX) solvent without extractant in caustic salt solution at evaporator-relevant temperatures result in no process-significant energetic events. However, the data suggest a chemical reaction (possible decomposition) in the CSSX solvent near 140 C. This concentration of entrained solvent is believed to markedly exceed the amount of solvent that will pass from the Modular Caustic Side Solvent Unit (MCU) through the downstream Defense Waste Processing Facility and enter the evaporator through routine tank farm operations. The rate of pressure rise at 140 C differs appreciably - i.e., is reduced - for salt solution containing the organic from that of the same solution without solvent. This behavior is due to a reaction between the CSSX components and the salt solution simulant.

  19. Rebirth through supported employment.

    PubMed

    Strickler, David C

    2014-06-01

    In this column, the author describes how supported employment was a conduit for employment for him, and allowed for a remarkable journey of recovery, involving discovery and empowerment, incorporation, purpose, and belonging. After two decades of unemployment or underemployment, he began to see that work was possible through supported education at college, where he excelled. Federal and state grants paid for two thirds of his college education. He periodically met with a vocational rehabilitation counselor, who was very encouraging. He also had a case manager through a private psychiatric organization who provided support. The author concludes that the root of his problems was the lack of supports to help him become incorporated into society-a lack that ushered in a host of problems, probably similar to what others experience. When supports were given, many of those symptoms disappeared.

  20. Organic Solvent Tolerant Lipases and Applications

    PubMed Central

    Kanwar, Shamsher S.

    2014-01-01

    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. PMID:24672342

  1. Differential response of marine diatoms to solvents

    SciTech Connect

    Tadros, M.G.; Phillips, J.; Patel, H.; Pandiripally, V.

    1995-06-01

    Unicellular algae in aquatic ecosystems are subjected to a variety of pollutants from sources such as runoff from agricultural lands and industrial outfalls. Organic solvents are natural components of oil deposits and commonly find their way into surface waters as a result of discharges from refineries, waste oil, disposal, and accidental spills. Organic solvents can make their way into the environment as industrial wastes. Because of their carcinogenic potential, contamination of soil and water by solvents is cause for serious concern. Relatively few reports have been published on the comparative toxicity of solvents towards test organisms, and these dealt primarily with fish and aquatic invertebrates. However, only few data of toxicity effects of solvents on algae have been published. Phytoplankton species vary in their tolerance to trace metals. Diatoms in particular are able to detoxify trace metals by the excretion of organic compounds. A previous study reported that diatoms collected form different sites in the Gulf of Mexico varied in their physiological characteristics. Algae have been considered to be good indicator s of bioactivity of industrial wastes. Unicellular algae vary in their response to a variety of toxicants. Little is known, however, about toxicity of solvents to marine diatoms. The work reported here was done to examine the effect of selected solvents on seven diatom species to determine whether they differed in their responses to these chemicals. 16 refs., 1 fig.

  2. Effect of solvent characteristics on coal liquefaction

    SciTech Connect

    Huang, He; Wang, Shaojie; Wang, Keyu; Klein, M.T.; Calkins, W.H.

    1996-12-31

    It has been known for a long time that the characteristics of the liquefaction solvent has a profound effect on direct coal liquefaction. The amount of hydrogen consumed during the liquefaction process, the degree and quantity of retrograde reactions that occur, and the quality of the liquid products are all influenced by the process solvent. A number of analytical approaches have been developed to determine the important characteristics of the solvent for coal liquefaction. The hydrogen donor ability has clearly been important. However, such other characteristics of a liquefaction solvent as solubility parameter, content and type of higher aromatic hydrocarbons, and phenolic content have also been found to be significant. Finseth et al. have shown that the bulk of the hydrogen consumed from an uncatalyzed donor solvent liquefaction above 400{degrees}C is consumed in gas generation, heteroatom removal and hydrogenolysis of the coal matrix. Wilson et al. have also shown that the major role of hydrogen in uncatalyzed liquefaction is consumed by alkyl fission and hydrogenolysis reactions and not with hydrogenating aromatic rings. McMillan et al. have postulated that a radical hydrogen transfer process along with donor solvent capping of thermally produced radicals from the coal as possible processes involved with the hydroaromatic donor solvents in coal liquefaction. With the development of a short contact time batch reactor (SCTBR), determining the influence of the processing solvent on the liquefaction rates, conversion profiles and the quality of the liquid product at a particular time became possible. The influence of type of solvent, combined with other effects, such as gas atmosphere (i.e., in hydrogen and in nitrogen) and catalyst, on the coal liquefaction is reported in this paper.

  3. THE DESIGN OF TECHNOLOGICALLY EFFECTIVE AND ENVIRONMENTALLY BENIGN SOLVENT SUBSTITUTES

    EPA Science Inventory

    There is presently considerable interest in finding environmentally benign replacement solvents that can perform in many different applications as solvents normally do. This requires solvents with desirable properties, e.g., ability to dissolve certain compounds, and without oth...

  4. Firing of pulverized solvent refined coal

    DOEpatents

    Lennon, Dennis R.; Snedden, Richard B.; Foster, Edward P.; Bellas, George T.

    1990-05-15

    A burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired successfully without any performance limitations and without the coking of the solvent refined coal on the burner components. The burner is provided with a tangential inlet of primary air and pulverized fuel, a vaned diffusion swirler for the mixture of primary air and fuel, a center water-cooled conical diffuser shielding the incoming fuel from the heat radiation from the flame and deflecting the primary air and fuel steam into the secondary air, and a watercooled annulus located between the primary air and secondary air flows.

  5. Switchable solvents and methods of use thereof

    DOEpatents

    Jessop, Philip G.; Eckert, Charles A.; Liotta, Charles L.; Heldebrant, David J.

    2011-07-19

    A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

  6. Switchable solvents and methods of use thereof

    DOEpatents

    Jessop, Philip G.; Eckert, Charles A.; Liotta, Charles L.; Heldebrant, David J.

    2013-08-20

    A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

  7. Mechanism of paint removing by organic solvents

    SciTech Connect

    Del Nero, V.; Siat, C.; Marti, M.J.; Aubry, J.M.; Lallier, J.P.; Dupuy, N.; Huvenne, J.P.

    1996-01-01

    The mechanism of paint removing has been studied by comparing the stripping efficiency of a given solvent with its ability to swell the film. The most effective solvents have a Hildebrand{close_quote}s parameter, {delta}{sub H}, ranging from 10.5 to 12 and a Dimroth parameter, ET{sub (30)}, ranging from 0.25 to 0.4. The synergy observed with the mixtures DMSO/non polar solvent is explained by a dissociation of the DMSO clusters into individual molecules which diffuse more easily. {copyright} {ital 1996 American Institute of Physics.}

  8. What makes critical-solvent processes work

    SciTech Connect

    Brule, M.R.; Corbett, R.W.

    1984-06-01

    Critical-solvent processing (sometimes called supercritical-gas extraction) is an ongoing technology based on phase-equilibrium phenomena in the critical region. Many new practical applications of critical-solvent processing are being conceived and implemented in the food, drug and chemical industries. The advantages afforded by critical-solvent processing in performing difficult separations such as caffeine from coffee, nicotine from tobacco, chemotherapeutic drugs from plants, and chemical feedstocks from petroleum and synfuels residua have been realized just in the last decade or so.

  9. Reduction of solvent emissions from vapor degreasing

    SciTech Connect

    Buresh, P.

    1989-12-31

    Hutchinson Tehnology, Inc. (HTI) implemented a number of low cost, low technology procedures to reduce emissions and prevent solvent loss from two open-top freon (CFC-113) vapor degreasers (Branson No. 1 and No. 2). HTI is a computer components manufacturer that uses freon vapor degreasing systems to remove fluxes and other residues remaining on the flexible printed circuits from the soldering process. With relatively minor changes in operation, solvent emissions were reduced by an average of 2.8 gallons per day (GDP) for both degreasers combined. It is anticipated that HTI will follow through with installation of an automatic cover, which can result in further solvent emissions reduction.

  10. Optical nonlinearity of HBI in different solvents

    NASA Astrophysics Data System (ADS)

    Wu, Feng; Ma, Lina; Geng, Yaohui; Zhang, Siwen; Wang, Zhe; Cheng, Xiaoman

    2014-04-01

    2-(2'-Hydroxyphenyl) benzimidazole (HBI) is one kind of organic molecules featuring excited-state proton transfer (ESPT). The nonlinear optical properties of 2-(2'-hydroxyphenyl) benzimidazole (HBI) in different polar solvents were investigated by means of Z-scan technique under the excitation of the 1064 nm picoseconds laser pulse. The experimental results show that the nonlinear refractive indices decrease with the enhancement of the polarity of the solvent. The nonlinear refractive indices sensitive to the solvent polarity allow them to be widely used for the optoelectronic devices.

  11. Switchable solvents and methods of use thereof

    SciTech Connect

    Jessop, Philip G; Eckert, Charles A; Liotta, Charles L; Heldebrant, David J

    2014-04-29

    A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

  12. Cleaning solvent substitution in electronic assemblies

    SciTech Connect

    Meier, G.J.

    1993-09-01

    Alternatives to chlorinated and fluorinated solvents have been identified, qualified, and implemented into production of complex electronic assemblies. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, has been selected as the solvent of choice for cleaning complex electronic assemblies, and has been found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data.

  13. Genomic and Genetic Approaches to Solvent Tolerance

    SciTech Connect

    Eleftherios T. Papoutsakis

    2005-06-10

    The proposed research is to understand and exploit the molecular basis that determines tolerance of the industrially important anaerobic clostridia to solvents. Furthermore, we aim to develop general genomic and metabolic engineering strategies for understanding the molecular basis of tolerance to chemicals and for developing tolerant strains. Our hypothesis is that the molecular basis of what makes bacterial cells able to withstand high solvent concentrations can be used to metabolically engineer cells so that they can tolerate higher concentrations of solvents and related chemicals.

  14. Energy requirements for wet solvent extraction of lipids from microalgal biomass.

    PubMed

    Martin, Gregory J O

    2016-04-01

    Biofuel production from microalgae requires energy efficient processes for extracting and converting triacylglyceride lipids to fuel, compatible with coproduction of protein feeds and nutraceuticals. Wet solvent extraction involves mechanical cell rupture, lipid extraction via solvent contacting, physical phase separation, thermal solvent recovery, and transesterification. A detailed analysis of the effect of key process parameters on the parasitic energy demand of this process was performed. On a well-to-pump basis, between 16% and 320% of the resultant biodiesel energy was consumed depending solely on the process parameters. Highly positive energy balances can be achieved, but only if a correctly designed process is used. This requires processing concentrated biomass (ca 25%w/w) with a high triacylglyceride content (ca 30%w/w), and an efficient extraction process employing a non-polar solvent, low solvent-to-paste ratio, and efficient energy recovery. These requirements preclude many laboratory scale processes and polar co-solvents as viable options for large-scale biofuel production.

  15. Physical Solvents that are Alternatives for PEGDME in CO{sub 2} Absorption

    SciTech Connect

    Miller, M.B.; Luebke, D.R.; Enick, R.M.

    2011-03-01

    Advanced gasification power plants will employ the water-gas shift reaction producing a high pressure gas-phase mixture containing CO{sub 2}, H{sub 2} and water. This gas mixture at elevated pressures provides ample driving force in order to use a physical solvent that will selectively absorb, not chemically bind, to the CO{sub 2}. Potential physical absorbers include (a) liquid mixtures of CO{sub 2}-philic polydisperse oligomers, (b) small, volatile, liquid CO{sub 2}-philic solvents, and (c) CO{sub 2}-philic solids capable of melting in the presence of CO{sub 2}. The objective of this study was to identify alternative physical solvents that would selectively dissolve only CO{sub 2} from this mixture. The first phase of our research involved the comparison of the CO{sub 2} solvent strength of PEGDME with that of other low volatility oligomers that are known to be “CO{sub 2}-philic”. Small volatile CO{sub 2} solvents were also examined in the second phase of this work. Lastly, solid CO{sub 2}-philes have been investigated as a potential CO{sub 2} solvent.

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

    PubMed

    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. PMID:26822320

  17. Graduate Employability: A Conceptual Framework for Understanding Employers' Perceptions

    ERIC Educational Resources Information Center

    Cai, Yuzhuo

    2013-01-01

    This study provides a conceptual framework for understanding what employers think about the value of graduates with similar educational credentials in the workplace (their employability), using insights from the new institutionalism. In this framework, the development of employers' beliefs about graduates' employability is broken into a number of…

  18. Biological monitoring of chlorinated hydrocarbon solvents

    SciTech Connect

    Monster, A.C.

    1986-08-01

    The possibility of biological monitoring of exposure to some volatile, halogenated hydrocarbons will be discussed. Most of these agents are widely used as solvents. All agents act on the nervous system as narcotics and differ widely in toxicity. Most of the solvents undergo biotransformation to metabolites. This allows biological assessment of exposure by measurement of the solvent and/or metabolites in exhaled air, blood, and/or urine. However, the same metabolites may occur with exposure to different chlorinated hydrocarbons, eg, trichloroethanol and trichloroacetic acid from exposure to trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane. On the other hand, these agents differ widely in the percentage that is metabolized. There are large gaps in our knowledge, however, and much research will have to be carried out before even tentative data can be established for most of the solvents.

  19. "Solvent Effects" in 1H NMR Spectroscopy.

    ERIC Educational Resources Information Center

    Cavaleiro, Jose A. S.

    1987-01-01

    Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

  20. United States Air Force Wipe Solvent Testing

    NASA Technical Reports Server (NTRS)

    Hornung, Steven D.; Beeson, Harold D.

    2000-01-01

    The Wright-Patterson Air Force Base (WPAFB), as part of the Air Force Material Command, requested that NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) conduct testing and analyses in support of the United States Air Force Wipe Solvent Development Project. The purpose of the wipe solvent project is to develop an alternative to be used by Air Force flight line and maintenance personnel for the wipe cleaning of oxygen equipment. This report provides material compatibility, liquid oxygen (LOX) mechanical impact, autogenous ignition temperature (AIT), and gauge cleaning test data for some of the currently available solvents that may be used to replace CFC-113 and methyl chloroform. It provides data from previous WSTF test programs sponsored by the Naval Sea Systems Command, the Kennedy Space Center, and other NASA programs for the purpose of assisting WP AFB in identifying the best alternative solvents for validation testing.

  1. Innovative Technologies for Chlorinated Solvent Remediation

    NASA Astrophysics Data System (ADS)

    Pennell, Kurt D.; Cápiro, Natalie L.

    2014-07-01

    The following sections are included: * INTRODUCTION * TRADITIONAL REMEDIATION TECHNOLOGIES (1980s) * RESEARCH AND DEVELOPMENT OF INNOVATIVE REMEDIATION TECHNOLOGIES (1990s-2000s) * CURRENT TRENDS IN CHLORINATED SOLVENT REMEDIATION (2010s) * CLOSING THOUGHTS * REFERENCES

  2. Surface functionalization of SBA-15 by the solvent-free method

    SciTech Connect

    Wang Yimeng; Zheng Yingwu; Zhu Jianhua . E-mail: jhzhu@netra.nju.edu.cn

    2004-10-01

    A solvent-free technique was employed for fast modification of mesoporous materials. Copper, chromium and iron oxide species could be highly dispersed in SBA-15 by manually grinding the corresponding precursor salts and the host, followed by calcinations for the first time. This method is more effective to spontaneously disperse oxide species onto SBA-15 than impregnation, probably forming monolayer or submonolayer dispersion of salts or oxides. Besides, Cr(VI) species dominate in the mixing sample while Cr(III) species dominate in the impregnation one. In the temperature programmed surface reaction of nitrosamines, the sample prepared by solvent-free method showed a higher catalytic activity than the impregnation one.

  3. Water as a Solvent for Life

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; Pratt, Lawrence R.

    2015-01-01

    "Follow the water" is our basic strategy in searching for life in the universe. The universality of water as the solvent for living systems is usually justified by arguing that water supports the rich organic chemistry that seeds life, but alternative chemistries are possible in other organic solvents. Here, other, essential criteria for life that have not been sufficiently considered so far, will be discussed.

  4. Screening evaluation of alternative cleaning solvents

    SciTech Connect

    Nigrey, P.J.

    1991-01-01

    The cleaning efficiency of five alternative solvents for chlorofluorocarbons (CFCs) and chlorohydrocarbons (CHCs) used in the manufacture of certain electronic components was studied. These solvents were evaluated in the first phase of a two-phase program to remove various manufacturing contaminants such as oils, greases, mold release, and body oils. Results have shown that EXXATE 1000 and EC-7 were able to effectively remove these contaminants from copper board substrates. 4 refs., 5 figs., 1 tab.

  5. Dispersion of carbon nanotubes using organic solvents.

    PubMed

    Dumonteil, S; Demortier, A; Detriche, S; Raes, C; Fonseca, A; Rühle, M; Nagy, J B

    2006-05-01

    Phenyl ethyl alcohol was used for fast and stable dispersion of carbon nanotubes. This solvent, more effective than ethanol and toluene, allows easy dispersion of carbon nanotubes for TEM characterization. For TEM grids prepared at high dilution, it is possible to observe each tube separately. Applying that solvent, it was possible to measure the length, the diameter and the solubility of different carbon nanotubes samples.

  6. Method of stripping metals from organic solvents

    DOEpatents

    Todd, Terry A.; Law, Jack D.; Herbst, R. Scott; Romanovskiy, Valeriy N.; Smirnov, Igor V.; Babain, Vasily A.; Esimantovski, Vyatcheslav M.

    2009-02-24

    A new method to strip metals from organic solvents in a manner that allows for the recycle of the stripping agent. The method utilizes carbonate solutions of organic amines with complexants, in low concentrations, to strip metals from organic solvents. The method allows for the distillation and reuse of organic amines. The concentrated metal/complexant fraction from distillation is more amenable to immobilization than solutions resulting from current practice.

  7. Biofiltration of solvent vapors from air

    SciTech Connect

    Oh, Young-sook.

    1993-01-01

    For various industrial solvent vapors, biofiltration promises to offer a cost-effective emission control technology. Exploiting the full potential of this technology will help attain the goals of the Clean Air Act Amendments of 1990. Concentrating on large volumes of volatile industrial solvents, stable multicomponent microbial enrichments capable of growing a mineral medium with solvent vapors as their only source of carbon and energy were obtained from soil and sewage sludge. These consortia were immobilized on an optimized porous solid support (ground peat moss and perlite). The biofilter material was packed in glass columns connected to an array of pumps and flow meters that allowed the independent variation of superficial velocity and solvent vapor concentrations. In various experiments, single solvents, such as methanol, butanol, acetonitrile, hexane and nitrobenzene, and solvent mixtures, such as benzene-toluene-xylene (BTX) and chlorobenzene-o-dichlorobenzene (CB/DCB) were biofiltered with rates ranging from 15 to334 g solvent removed per m[sup 3] filter volume /h. Pressure drops were low to moderate (0-10 mmHg/m) and with periodic replacement of moisture, the biofiltration activity could be maintained for a period of several months. The experimental data on methanol biofiltration were subjected to mathematical analysis and modeling by the group of Dr. Baltzis at NJIT for a better understanding and a possible scale up of solvent vapor biofilters. In the case of chlorobenzenes and nitrobenzene, the biofilter columns had to be operated with water recirculation in a trickling filter mode. To prevent inactivation of the trickling filter by acidity during CB/DCB removal, pH control was necessary, and the removal rate of CB/DCB was strongly influenced by the flow rate of the recyling water. Nitrobenzene removal in a trickling filter did not require pH control, since the nitro group was reduced and volatilized as ammonia.

  8. Solvent extraction behaviour of thiocyanic acid.

    PubMed

    Jurriaanse, A; Kemp, D M

    1968-11-01

    The solvent extraction behaviour of thiocyanic acid with isobutyl methyl ketone and xylene as solvents is described. In the ketone system the thiocyanic acid is solvated in the organic phase to give a complex with a proposed composition of HSCN. 2IBMK. Deviations from ideal behaviour, which can be attributed to variations in the activity coefficient of the acid in the aqueous phase, are shown.

  9. Competitive solvent-molecule interactions govern primary processes of diphenylcarbene in solvent mixtures

    PubMed Central

    Knorr, Johannes; Sokkar, Pandian; Schott, Sebastian; Costa, Paolo; Thiel, Walter; Sander, Wolfram; Sanchez-Garcia, Elsa; Nuernberger, Patrick

    2016-01-01

    Photochemical reactions in solution often proceed via competing reaction pathways comprising intermediates that capture a solvent molecule. A disclosure of the underlying reaction mechanisms is challenging due to the rapid nature of these processes and the intricate identification of how many solvent molecules are involved. Here combining broadband femtosecond transient absorption and quantum mechanics/molecular mechanics simulations, we show for one of the most reactive species, diphenylcarbene, that the decision-maker is not the nearest solvent molecule but its neighbour. The hydrogen bonding dynamics determine which reaction channels are accessible in binary solvent mixtures at room temperature. In-depth analysis of the amount of nascent intermediates corroborates the importance of a hydrogen-bonded complex with a protic solvent molecule, in striking analogy to complexes found at cryogenic temperatures. Our results show that adjacent solvent molecules take the role of key abettors rather than bystanders for the fate of the reactive intermediate. PMID:27708264

  10. Competitive solvent-molecule interactions govern primary processes of diphenylcarbene in solvent mixtures

    NASA Astrophysics Data System (ADS)

    Knorr, Johannes; Sokkar, Pandian; Schott, Sebastian; Costa, Paolo; Thiel, Walter; Sander, Wolfram; Sanchez-Garcia, Elsa; Nuernberger, Patrick

    2016-10-01

    Photochemical reactions in solution often proceed via competing reaction pathways comprising intermediates that capture a solvent molecule. A disclosure of the underlying reaction mechanisms is challenging due to the rapid nature of these processes and the intricate identification of how many solvent molecules are involved. Here combining broadband femtosecond transient absorption and quantum mechanics/molecular mechanics simulations, we show for one of the most reactive species, diphenylcarbene, that the decision-maker is not the nearest solvent molecule but its neighbour. The hydrogen bonding dynamics determine which reaction channels are accessible in binary solvent mixtures at room temperature. In-depth analysis of the amount of nascent intermediates corroborates the importance of a hydrogen-bonded complex with a protic solvent molecule, in striking analogy to complexes found at cryogenic temperatures. Our results show that adjacent solvent molecules take the role of key abettors rather than bystanders for the fate of the reactive intermediate.

  11. Process for solvent refining of coal using a denitrogenated and dephenolated solvent

    DOEpatents

    Garg, Diwakar; Givens, Edwin N.; Schweighardt, Frank K.

    1984-01-01

    A process is disclosed for the solvent refining of non-anthracitic coal at elevated temperatures and pressure in a hydrogen atmosphere using a hydrocarbon solvent which before being recycled in the solvent refining process is subjected to chemical treatment to extract substantially all nitrogenous and phenolic constituents from the solvent so as to improve the conversion of coal and the production of oil in the solvent refining process. The solvent refining process can be either thermal or catalytic. The extraction of nitrogenous compounds can be performed by acid contact such as hydrogen chloride or fluoride treatment, while phenolic extraction can be performed by caustic contact or contact with a mixture of silica and alumina.

  12. Employment in the Public Sector.

    ERIC Educational Resources Information Center

    Organisation for Economic Cooperation and Development, Paris (France).

    This report synthesizes the findings from several areas of work undertaken to assess what impact public sector employment has had on both the level and structure of employment. It also examines the impact of the public sector as employer on the labor market from two viewpoints: the level and share of public sector employment and the structure of…

  13. Employability Skills Assessment Tool Development

    ERIC Educational Resources Information Center

    Rasul, Mohamad Sattar; Rauf, Rose Amnah Abd; Mansor, Azlin Norhaini; Puvanasvaran, A. P.

    2012-01-01

    Research nationally and internationally found that technical graduates are lacking in employability skills. As employability skills are crucial in outcome-based education, the main goal of this research is to develop an Employability Skill Assessment Tool to help students and lecturers produce competent graduates in employability skills needed by…

  14. Employability. NIACE Briefing Sheet 88

    ERIC Educational Resources Information Center

    National Institute of Adult Continuing Education, 2009

    2009-01-01

    Employability skills are central to gaining and keeping employment (e.g. whether paid or unpaid, as an employee or self employed) as well as career progression. The lack of such skills is regularly referred to as one reason for the United Kingdom's often cited long tail of underachievement. Employability skills are at the forefront of government…

  15. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1991-08-01

    Research continued on the determination of pore size and number distribution changes after swelling the coal samples with various solvents. A paper has just been submitted to the journal Fuel on the Low temperature Swelling of Argonne Premium Coal samples using solvents of varying polarity. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities. A copy of this paper has been attached to this report. Wojciech Sady has determine the structural changes in the pores that occur when APCS coal is dehydrated prior to swelling with polar solvents. These changes are different from those that occur in the absence of prior dehydration. He has also completed a study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents. A statistical analysis of the data is currently underway to determine important trends in his data. 9 refs.

  16. Solvent dependent photophysical properties of dimethoxy curcumin

    NASA Astrophysics Data System (ADS)

    Barik, Atanu; Indira Priyadarsini, K.

    2013-03-01

    Dimethoxy curcumin (DMC) is a methylated derivative of curcumin. In order to know the effect of ring substitution on photophysical properties of curcumin, steady state absorption and fluorescence spectra of DMC were recorded in organic solvents with different polarity and compared with those of curcumin. The absorption and fluorescence spectra of DMC, like curcumin, are strongly dependent on solvent polarity and the maxima of DMC showed red shift with increase in solvent polarity function (Δf), but the above effect is prominently observed in case of fluorescence maxima. From the dependence of Stokes' shift on solvent polarity function the difference between the excited state and ground state dipole moment was estimated as 4.9 D. Fluorescence quantum yield (ϕf) and fluorescence lifetime (τf) of DMC were also measured in different solvents at room temperature. The results indicated that with increasing solvent polarity, ϕf increased linearly, which has been accounted for the decrease in non-radiative rate by intersystem crossing (ISC) processes.

  17. Solvent dependent photophysical properties of dimethoxy curcumin.

    PubMed

    Barik, Atanu; Indira Priyadarsini, K

    2013-03-15

    Dimethoxy curcumin (DMC) is a methylated derivative of curcumin. In order to know the effect of ring substitution on photophysical properties of curcumin, steady state absorption and fluorescence spectra of DMC were recorded in organic solvents with different polarity and compared with those of curcumin. The absorption and fluorescence spectra of DMC, like curcumin, are strongly dependent on solvent polarity and the maxima of DMC showed red shift with increase in solvent polarity function (Δf), but the above effect is prominently observed in case of fluorescence maxima. From the dependence of Stokes' shift on solvent polarity function the difference between the excited state and ground state dipole moment was estimated as 4.9 D. Fluorescence quantum yield (φ(f)) and fluorescence lifetime (τ(f)) of DMC were also measured in different solvents at room temperature. The results indicated that with increasing solvent polarity, φ(f) increased linearly, which has been accounted for the decrease in non-radiative rate by intersystem crossing (ISC) processes. PMID:23314392

  18. Solvent Extraction and Ion Exchange in Radiochemistry

    NASA Astrophysics Data System (ADS)

    Skarnemark, G.

    In 1805, Bucholz extracted uranium from a nitric acid solution into ether and back-extracted it into pure water. This is probably the first reported solvent-extraction investigation. During the following decades, the distribution of neutral compounds between aqueous phases and pure solvents was studied, e.g., by Peligot, Berthelot and Jungfleisch, and Nernst. Selective extractants for analytical purposes became available during the first decades of the twentieth century. From about 1940, extractants such as organophosphorous esters and amines were developed for use in the nuclear fuel cycle. This connection between radiochemistry and solvent-extraction chemistry made radiochemists heavily involved in the development of new solvent extraction processes, and eventually solvent extraction became a major separation technique in radiochemistry. About 160 years ago, Thompson and Way observed that soil can remove potassium and ammonium ions from an aqueous solution and release calcium ions. This is probably the first scientific report on an ion-exchange separation. The first synthesis of the type of organic ion exchangers that are used today was performed by Adams and Holmes in 1935. Since then, ion-exchange techniques have been used extensively for separations of various radionuclides in trace as well as macro amounts. During the last 4 decades, inorganic ion exchangers have also found a variety of applications. Today, solvent extraction as well as ion exchange are used extensively in the nuclear industry and for nuclear, chemical, and medical research. Some of these applications are discussed in the chapter.

  19. Caustic-Side Solvent Extraction: Chemical and Physical Properties of the Optimized Solvent

    SciTech Connect

    Delmau, L.H.

    2002-10-08

    This work was undertaken to optimize the solvent used in the Caustic Side Solvent Extraction (CSSX) process and to measure key chemical and physical properties related to its performance in the removal of cesium from the alkaline high-level salt waste stored in tanks at the Savannah River Site. The need to adjust the solvent composition arose from the prior discovery that the previous baseline solvent was supersaturated with respect to the calixarene extractant. The following solvent-component concentrations in Isopar{reg_sign} L diluent are recommended: 0.007 M calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) extractant, 0.75 M 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) phase modifier, and 0.003 M tri-n-octylamine (TOA) stripping aid. Criteria for this selection included BOBCalixC6 solubility, batch cesium distribution ratios (D{sub Cs}), calculated flowsheet robustness, third-phase formation, coalescence rate (dispersion numbers), and solvent density. Although minor compromises within acceptable limits were made in flowsheet robustness and solvent density, significant benefits were gained in lower risk of third-phase formation and lower solvent cost. Data are also reported for the optimized solvent regarding the temperature dependence of D{sub Cs} in extraction, scrubbing, and stripping (ESS); ESS performance on recycle; partitioning of BOBCalixC6, Cs-7SB, and TOA to aqueous process solutions; partitioning of organic anions; distribution of metals; solvent phase separation at low temperatures; solvent stability to elevated temperatures; and solvent density and viscosity. Overall, the technical risk of the CSSX process has been reduced by resolving previously identified issues and raising no new issues.

  20. Influence of solvent polarity on preferential solvation of molecular recognition probes in solvent mixtures.

    PubMed

    Amenta, Valeria; Cook, Joanne L; Hunter, Christopher A; Low, Caroline M R; Vinter, Jeremy G

    2012-12-13

    The association constants for formation of 1:1 complexes between a H-bond acceptor, tri-n-butylphosphine oxide, and a H-bond donor, 4-phenylazophenol, have been measured in a range of different solvent mixtures. Binary mixtures of n-octane and a more polar solvent (ether, ester, ketone, nitrile, sulfoxide, tertiary amide, and halogenated and aromatic solvents) have been investigated. Similar behavior was observed in all cases. When the concentration of the more polar solvent is low, the association constant is identical to that observed in pure n-octane. Once a threshold concentration of the more polar solvent in reached, the logarithm of the association constant decreases in direct proportion to the logarithm of the concentration of the more polar solvent. This indicates that one of the two solutes is preferentially solvated by the more polar solvent, and it is competition with this solvation equilibrium that determines the observed association constant. The concentration of the more polar solvent at which the onset of preferential solvation takes place depends on solvent polarity: 700 mM for toluene, 60 mM for 1,1,2,2-tetrachloroethane, 20 mM for the ether, ester, ketone, and nitrile, 0.2 mM for the tertiary amide, and 0.1 mM for the sulfoxide solvents. The results can be explained by a simple model that considers only pairwise interactions between specific sites on the surfaces of the solutes and solvents, which implies that the bulk properties of the solvent have little impact on solvation thermodynamics. PMID:23190174

  1. Influence of solute-solvent coordination on the orientational relaxation of ion assemblies in polar solvents

    NASA Astrophysics Data System (ADS)

    Ji, Minbiao; Hartsock, Robert W.; Sung, Zheng; Gaffney, Kelly J.

    2012-01-01

    We have investigated the rotational dynamics of lithium thiocyanate (LiNCS) dissolved in various polar solvents with time and polarization resolved vibrational spectroscopy. LiNCS forms multiple distinct ionic structures in solution that can be distinguished with the CN stretch vibrational frequency of the different ionic assemblies. By varying the solvent and the LiNCS concentration, the number and type of ionic structures present in solution can be controlled. Control of the ionic structure provides control over the volume, shape, and dipole moment of the solute, critical parameters for hydrodynamic and dielectric continuum models of friction. The use of solutes with sizes comparable to or smaller than the solvent molecules also helps amplify the sensitivity of the measurement to the short-ranged solute-solvent interaction. The measured orientational relaxation dynamics show many clear and distinct deviations from simple hydrodynamic behavior. All ionic structures in all solvents exhibit multi-exponential relaxation dynamics that do not scale with the solute volume. For Lewis base solvents such as benzonitrile, dimethyl carbonate, and ethyl acetate, the observed dynamics strongly show the effect of solute-solvent complex formation. For the weak Lewis base solvent nitromethane, we see no evidence for solute-solvent complex formation, but still see strong deviation from the predictions of simple hydrodynamic theory.

  2. CHEMICAL STABILITY OF POLYPHENYLENE SULFIDE IN THE NEXT GENERATION SOLVENT FOR CAUSTIC-SIDE SOLVENT EXTRACTION

    SciTech Connect

    Fondeur, F.; Fink, S.

    2011-12-08

    The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. For simplicity, this solvent is referred to as the Next Generation Solvent (NGS). The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The initial deployment target envisioned for the technology was within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with polyphenylene sulfide (PPS), the polymer used in the coalescers within MCU. This report provides the data from exposing PPS polymer to NGS. The test was conducted over a three month period. PPS is remarkably stable in the presence of the next generation solvent. Testing showed no indication of swelling or significant leaching. Preferential sorption of the Modifier on PPS was observed but the same behavior occurs with the baseline solvent. Therefore, PPS coalescers exposed to the NGS are expected to perform comparably to those in contact with the baseline solvent.

  3. Fluorophore exchange kinetics in block copolymer micelles with varying solvent-fluorophore and solvent-polymer interactions.

    PubMed

    Xie, Michelle; Wang, Shu; Singh, Avantika; Cooksey, Tyler J; Marquez, Maria D; Bhattarai, Ashish; Kourentzi, Katerina; Robertson, Megan L

    2016-07-20

    Fluorescence spectroscopy was employed to characterize the kinetics of guest exchange in diblock copolymer micelles composed of poly(ethylene oxide-b-ε-caprolactone) (PEO-PCL) diblock copolymers in water/tetrahydrofuran (THF) mixtures which encapsulated fluorophores. The solvent composition (THF content) of the micelle solution was varied as a means of modulating the strength of interactions between the fluorophore and solvent as well as between the micelle core and solvent. A donor-acceptor fluorophore pair was employed consisting of 3,3'-dioctadecyloxacarbocyanine perchlorate (DiO, the donor) and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI, the acceptor). Through the process of Förster resonance energy transfer (FRET), energy was transferred from the donor to acceptor when the fluorophores were in close proximity. A micelle solution containing DiO was mixed with a micelle solution containing DiI at t = 0, and the emission spectra of the mixed solution were monitored over time (at an excitation wavelength optimized for the donor). In micelle solutions containing 5 and 10 vol% THF in the bulk solvent, an increase in the acceptor peak intensity maximum occurred over time in the post-mixed solution, accompanied by a decrease in the donor peak intensity maximum, indicating the presence of energy transfer from the donor to the acceptor. At long times, the FRET ratios (acceptor peak intensity divided by the sum of the acceptor and donor peak intensities) were indistinguishable from that determined from pre-mixed micelle solutions of the same THF content (in pre-mixed solutions, DiO and DiI were encapsulated within the same micelle cores). In the micelle solution containing 20 vol% THF, the fluorophore exchange process occurred too quickly to be observed (the FRET ratios measured from the solutions mixed at t = 0 were commensurate to that measured from the pre-mixed solution). A time constant describing the guest exchange process was

  4. Stability of the Caustic-Side Solvent Extraction (CSSX) Process Solvent: Effect of High Nitrite on Solvent Nitration

    SciTech Connect

    Bonnesen, P.V.

    2002-06-26

    The purpose of this investigation was to determine whether nitrated organic compounds could be formed during operation of the Caustic-Side Solvent Extraction (CSSX) process, and whether such compounds would present a safety concern. The CSSX process was developed to remove cesium from alkaline high-level salt waste stored at the US Department of Energy Savannah River Site (SRS). The solvent is composed of the cesium extractant calix[4]arene-bis-(4-tert-octylbenzo-crown-6) (BOBCalixC6), a fluorinated alcohol phase modifier, tri-n-octylamine (TOA), and an isoparaffinic diluent (Iospar{reg_sign}). During the CSSX process, the solvent is expected to be exposed to high concentrations of nitrate and nitrite dissolved in the alkaline waste feed. The solvent will also be exposed to dilute (50 mM) nitric acid solutions containing low concentrations of nitrite during scrubbing, followed by stripping with 1 mM nitric acid. The solvent is expected to last for one year of plant operation, and the temperatures the solvent may experience during the process could range from as low as 15 C to as high as 35 C. Excursions from standard process conditions could result in the solvent experiencing higher temperatures, as well as concentrations of nitrate, nitrite, and most importantly nitric acid, that exceed normal operating conditions. Accordingly, conditions may exist where nitration reactions involving the solvent components, possibly leading to other chemical reactions stemming from nitration reactions, could occur. To model such nitration reactions, the solvent was exposed to the types of nitrate- and nitrite-containing solutions that might be expected to be encountered during the process (even under off-normal conditions), as a function of time, temperature, and concentration of nitrate, nitrite, and nitric acid. The experiments conducted as part of this report were designed to examine the more specific effect that high nitrite concentrations could have on forming nitrated

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

    PubMed

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

    1994-06-01

    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.

  6. Effect of surfactant and solvent on spin-lattice relaxation dynamics of magnetic nanocrystals.

    PubMed

    Maiti, Sourav; Chen, Hsiang-Yun; Chen, Tai-Yen; Hsia, Chih-Hao; Son, Dong Hee

    2013-04-25

    The effect of varying the surfactant and solvent medium on the dynamics of spin-lattice relaxation in photoexcited Fe3O4 nanocrystals has been investigated by measuring the time-dependent magnetization employing pump-probe transient Faraday rotation technique. The variation of the surfactants having surface-binding functional groups modified not only the static magnetization but also the dynamics of the recovery of the magnetization occurring via spin-lattice relaxation in the photoexcited Fe3O4 nanocrystals. The variation of the polarity and size of the solvent molecules can also influence the spin-lattice relaxation dynamics. However, the effect is limited to the nanocrystals having sufficiently permeable surfactant layer, where the small solvent molecules (e.g., water) can access the surface and dynamically modify the ligand field on the surface. PMID:23003213

  7. High-throughput determination of quantitative structure-property relationships using a resonant multisensor system: solvent resistance of bisphenol a polycarbonate copolymers.

    PubMed

    Potyrailo, Radislav A; McCloskey, Patrick J; Wroczynski, Ronald J; Morris, William G

    2006-05-01

    Polymers are important materials for sensor, microfluidic, and other demanding applications. High-throughput screening methodology has been applied for the evaluation of the solvent resistance of a family of polycarbonate copolymers prepared from the reaction of bisphenol A (BPA), hydroquinone (HQ), and resorcinol (RS) in different solvents of practical importance, such as chloroform, tetrahydrofuran (THF), and methyl ethyl ketone (MEK). We employed a 24-channel acoustic-wave sensor system that provided previously unavailable capabilities for parallel evaluation of polymer solvent resistance. This high-throughput polymer evaluation approach assisted in construction of detailed solvent-resistance maps of polycarbonate copolymers and in determination of quantitative structure-property relationships. The best absolute solvent resistance of all studied copolymers was achieved in MEK, followed by chloroform and THF. A D-optimal mixture design was employed to explore the relationship between the copolymer compositions and their solvent resistance. The applied special cubic model for each solvent took into account the primary mixture terms such as BPA, HQ, and RS; binary interaction terms such as BPA-HQ, BPA-RS, and HQ-RS; and a ternary interaction term BPA-HQ-RS. A combination of the normal distribution of the model residuals and the very high values of adjusted R2 (0.97-0.99) demonstrated a good quality of the model. At a HQ concentration of 40 mol %, the solvent resistance was the highest for all tested solvents, and different concentrations of BPA (40 and 60 mol %) and RS (0 and 20 mol %) did not affect the solvent resistance. Without HQ, solvent resistance was decreasing with an increase of RS and decrease of BPA. Overall, with an increase of HQ concentration from 0 to 40 mol %, the solvent resistance of BPA-HQ-RS copolymers was improved by up to 3 times in THF, by 21 times in chloroform, and by 32 times in MEK.

  8. Employment outcomes in Massachusetts Clubhouses.

    PubMed

    McKay, Colleen; Johnsen, Mathew; Stein, Reva

    2005-01-01

    Employment outcomes of individuals participating in 17 Massachusetts Clubhouses certified by the International Center for Clubhouse Development were examined through an annual survey. Major components of employment programs in contemporary clubhouses are identified and individual employment outcomes are described. Within contemporary practice in ICCD clubhouses in this sample, clubhouses provided a three-pronged approach to employment. Between 1998-2001, 1702 individuals worked in 2714 separate job placements, employed in Transitional (TE), Supported (SE), and Independent Employment (IE). Forty percent of members with more than one job (N = 385) participated in at least one TE. Individuals with longer memberships tended to work longer and had higher job earnings.

  9. Scale-up of recovery process for waste solvents

    NASA Astrophysics Data System (ADS)

    Bohnert, G. W.; Carey, D. A.

    1991-02-01

    Recycling of spent cleaning solvents, 1,1,1 trichloroethane, trichloroethylene, and trichlorotrifluoroethane at KCP was evaluated. Gas chromatography was used to identify stabilization levels in virgin and recycled solvent. Segregation, pretreatment, and distillation processes were defined. Existing distillation equipment was modified and a solvent drying process was added. Recycled solvent quality of several production lots is also presented.

  10. Scale-up of recovery process for waste solvents

    SciTech Connect

    Bohnert, G.W.; Carey, D.A.

    1991-02-01

    Recycling of spent cleaning solvents, 1,1,1 trichloroethane, trichloroethylene, and trichlorotrifluoroethane at KCP was evaluated. Gas chromatography was used to identify stabilization levels in virgin and recycled solvent. Segregation, pretreatment and distillation processes were defined. Existing distillation equipment was modified and a solvent drying process was added. Recycled solvent quality of several production lots is also presented. 3 figs., 4 tabs.

  11. Solvent disperser for removing oil from sponge core

    SciTech Connect

    Di Foggio, R.

    1988-09-20

    This patent describes method for dispersing solvent for use in determining the oil saturation of an earth formation by means of sponge coring, comprising: (a) receiving solvent dripping downwardly, and (b) conducting the received solvent by means of capillary action to an application zone located and dimensioned for passing such solvent to the sponge in a sponge core barrel.

  12. Preferential Solvation of a Highly Medium Responsive Pentacyanoferrate(II) Complex in Binary Solvent Mixtures: Understanding the Role of Dielectric Enrichment and the Specificity of Solute-Solvent Interactions.

    PubMed

    Papadakis, Raffaello

    2016-09-01

    In this work, the preferential solvation of an intensely solvatochromic ferrocyanide(II) dye involving a 4,4'-bipyridine-based ligand was examined in various binary solvent mixtures. Its solvatochromic behavior was rationalized in terms of specific and nonspecific solute-solvent interactions. An exceptional case of solvatochromic inversion was observed when going from alcohol/water to amide/water mixtures. These effects were quantified using Onsager's solvent polarity function. Furthermore, the sensitivity of the solvatochromism of the dye was determined using various solvatochromic parameters such as π* expressing the dipolarity/polarizability of solvents and α expressing the hydrogen-bond-donor acidity of solvents. This analysis was useful for the rationalization of the selective solvation phenomena occurring in the three types of alcohol/water and amide/water mixtures studied. Furthermore, two preferential solvation models were employed for the interpretation of the experimental spectral results in binary solvent mixtures, namely, the model of Suppan on dielectric enrichment [J. Chem. Soc. Faraday Trans. 1 1987, 83, 495-509] and the model of Bosch, Rosés, and co-workers [J. Chem. Soc., Perkin Trans. 2, 1995, 8, 1607-1615]. The first model successfully predicted the charge transfer energies of the dye in formamide/water and N-methylformamide/water mixtures, but in the case of MeOH/water mixtures, the prediction was less accurate because of the significant contribution of specific solute-solvent interactions in that case. The second model gave more insights for both specific solute-solvent as well as solvent-solvent interactions in the cybotactic region. The role of dielectric enrichment and specific interactions was discussed based on the findings. PMID:27525362

  13. Preferential Solvation of a Highly Medium Responsive Pentacyanoferrate(II) Complex in Binary Solvent Mixtures: Understanding the Role of Dielectric Enrichment and the Specificity of Solute-Solvent Interactions.

    PubMed

    Papadakis, Raffaello

    2016-09-01

    In this work, the preferential solvation of an intensely solvatochromic ferrocyanide(II) dye involving a 4,4'-bipyridine-based ligand was examined in various binary solvent mixtures. Its solvatochromic behavior was rationalized in terms of specific and nonspecific solute-solvent interactions. An exceptional case of solvatochromic inversion was observed when going from alcohol/water to amide/water mixtures. These effects were quantified using Onsager's solvent polarity function. Furthermore, the sensitivity of the solvatochromism of the dye was determined using various solvatochromic parameters such as π* expressing the dipolarity/polarizability of solvents and α expressing the hydrogen-bond-donor acidity of solvents. This analysis was useful for the rationalization of the selective solvation phenomena occurring in the three types of alcohol/water and amide/water mixtures studied. Furthermore, two preferential solvation models were employed for the interpretation of the experimental spectral results in binary solvent mixtures, namely, the model of Suppan on dielectric enrichment [J. Chem. Soc. Faraday Trans. 1 1987, 83, 495-509] and the model of Bosch, Rosés, and co-workers [J. Chem. Soc., Perkin Trans. 2, 1995, 8, 1607-1615]. The first model successfully predicted the charge transfer energies of the dye in formamide/water and N-methylformamide/water mixtures, but in the case of MeOH/water mixtures, the prediction was less accurate because of the significant contribution of specific solute-solvent interactions in that case. The second model gave more insights for both specific solute-solvent as well as solvent-solvent interactions in the cybotactic region. The role of dielectric enrichment and specific interactions was discussed based on the findings.

  14. Barriers to Employment: Personality and Cognitive Predictors of Employment Status

    ERIC Educational Resources Information Center

    McTurk, Carolyn; Shakespeare-Finch, Jane

    2006-01-01

    Barriers to employment are linked to individual factors such as thinking styles and personality traits. Personality and cognitive differences between employed (n = 55) and unemployed (n = 57) cohorts were analysed to quantify the association between these variables and employment status. Using the Myers-Briggs Type Indicator (MBTI) and the…

  15. Consumer and Employer Strategies for Overcoming Employment Barriers. Technical Report.

    ERIC Educational Resources Information Center

    Crudden, Adele; Williams, Wendy; McBroom, Lynn W.; Moore, J. Elton

    This report on strategies for overcoming employment barriers for persons with visual impairments summarizes comments and suggestions of 7 focus groups comprised of either consumers (n=49) or employers (n=19). The report first reviews the literature concerning employment barriers and how consumers in previous studies suggested these barriers be…

  16. A Conceptual Understanding of Employability: The Employers' View in Rwanda

    ERIC Educational Resources Information Center

    Bamwesiga, Penelope Mbabazi

    2013-01-01

    Many governments believe that investing in human capital should increase citizens' employability, which is why it is often presented as a solution to the problems of knowledge-based economies and societies, rising unemployment rates and economic competiveness. The aim of this study is to understand employers' views regarding the employability of…

  17. Disability and Supported Employment: Impact on Employment, Income, and Allowances

    ERIC Educational Resources Information Center

    Germundsson, Per; Gustafsson, Johanna; Lind, Martin; Danermark, Berth

    2012-01-01

    In this article, we examine supported employment and its impact on the level of employment, disposable income, and sum of allowances, targeting a group of individuals with disabilities. We have particularly focused on individuals with psychiatric disabilities. Supported employment is a vocational rehabilitation service with an empowerment approach…

  18. Temporary Employment and Perceived Employability: Mediation by Impression Management

    ERIC Educational Resources Information Center

    De Cuyper, Nele; De Witte, Hans

    2010-01-01

    Perceived employability (PE) has been advanced as the upcoming resource for career development, particularly for temporary workers. The question is how temporary workers become employable. Our hypothesis is that temporary workers more than permanent workers use impression management to become employable, both on the internal and the external labor…

  19. Integration of ceramic membrane and compressed air-assisted solvent extraction (CASX) for metal recovery.

    PubMed

    Li, Chi-Wang; Chiu, Chun-Hao; Lee, Yu-Cheng; Chang, Chia-Hao; Lee, Yu-Hsun; Chen, Yi-Ming

    2010-01-01

    In our previous publications, compressed air-assisted solvent extraction process (CASX) was developed and proved to be kinetically efficient process for metal removal. In the current study, CASX with a ceramic MF membrane integrated for separation of spent solvent was employed to remove and recover metal from wastewater. MF was operated either in crossflow mode or dead-end with intermittent flushing mode. Under crossflow mode, three distinct stages of flux vs. TMP (trans-membrane pressure) relationship were observed. In the first stage, flux increases with increasing TMP which is followed by the stage of stable flux with increasing TMP. After reaching a threshold TMP which is dependent of crossflow velocity, flux increases again with increasing TMP. At the last stage, solvent was pushed through membrane pores as indicated by increasing permeate COD. In dead-end with intermittent flushing mode, an intermittent flushing flow (2 min after a 10-min or a 30-min dead-end filtration) was incorporated to reduce membrane fouling by flush out MSAB accumulated on membrane surface. Effects of solvent concentration and composition were also investigated. Solvent concentrations ranging from 0.1 to 1% (w/w) have no adverse effect in terms of membrane fouling. However, solvent composition, i.e. D(2)EHPA/kerosene ratio, shows impact on membrane fouling. The type of metal extractants employed in CASX has significant impact on both membrane fouling and the quality of filtrate due to the differences in their viscosity and water solubility. Separation of MSAB was the limiting process controlling metal removal efficiency, and the removal efficiency of Cd(II) and Cr(VI) followed the same trend as that for COD.

  20. Hazardous solvents: Innovative alternatives offer choices

    SciTech Connect

    Melody, M.

    1993-01-01

    Use of hazardous solvents pose various problems for industry, including contributing to depletion of the stratospheric ozone layer, creating hazardous wastes and exposing workers to dangerous chemicals. Several environmental laws regulate the use of hazardous solvents, but only mandated phaseouts have prompted action by businesses. The CAA Amendments and the Montreal Protocol on Substances That Deplete the Ozone Layer are generating industry response, because they order the phaseout of two popular solvents -- CFCs and 1,1,1-trichloroethane. Regulations and hazardous waste disposal costs are the major factors influencing companies to switch to alternative cleaning solvents and technologies. Another factor contributing to the demand for alternative cleaners and processes is increased awareness of risks associated with hazardous solvents. Although most alternative cleaners do not have hazardous characteristics, the contaminants they remove may be hazardous. Vendors, therefore, are cautious about discussing waste disposal. Many facilities switching to aqueous and semi-aqueous systems need to install or modify wastewater treatment facilities, add a filtration system to recycle water, or buy water evaporators.

  1. Non-aqueous cleaning solvent substitution

    NASA Technical Reports Server (NTRS)

    Meier, Gerald J.

    1994-01-01

    A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of AlliedSignal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, was selected as the solvent of choice, and it was found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally-safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

  2. Non-aqueous cleaning solvent substitution

    SciTech Connect

    Meier, G.J.

    1994-01-01

    A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of Allied Signal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, has been selected as the solvent of choice, and has been found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

  3. Solvent gating of intramolecular electron transfer

    SciTech Connect

    Miller, R.M. ); Spears, K.G.; Gong, J.H.; Wach, M. )

    1994-02-03

    The rates for ionic photodissociation of malachite green leucocyanide to form cyanide ion and a malachite green carbonium ion were measured as a function of solvent and temperature. The observed rates in mixtures of polar and nonpolar solvents all had an activation energy of about 1 kcal/mol for a wide range of dielectric constants. This dissociative intramolecular electron transfer (DIET) is unusual because it is the first example where solvent configurational entropy changes are required to enable a large amplitude molecular distortion leading to a nonadiabatic electron transfer and ionic dissociation. This solvent gated intramolecular electron-transfer mechanism is supported by analysis of the preexponential and activation energy trends in dipolar aprotic solven mixtures and alcohol solvents. The large amplitude motion is not separately measurable due to the slow gating rates, but viscosity effects on both the preexponential and the activation energy are analyzed to demonstrate consistency with a barrierless diffusion model having a structural dependence on electron-transfer rate. The rate has an inverse dependence on viscosity raised to the 0.53 power. 36 refs., 6 figs., 4 tabs.

  4. Solvent extraction of phenols from water

    SciTech Connect

    Greminger, D.C.; Burns, G.P.; Lynn, S.; Hanson, D.H.; King, C.J.

    1980-02-01

    Methyl isobutyl ketone (MIBK) and diisopropyl ether (DIPE) have been evaluated as solvents for extraction of phenols, at high dilution, from water. Equilibrium distribution coefficients (K/sub D/) have been measured for phenol, dihydroxybenzenes and trihydroxybenzenes in both solvents as a function of pH. Particularly for the multihydric phenols, MIBK gives substantially higher values of K/sub D/ than does DIPE. The effect of pH can be described quantitatively through a simple ionization model, using published values of dissociation constants for the various phenols. Some method for removal of residual dissolved solvent must ordinarily be included in any extraction process for phenols. Possibilities include atmospheric-steam or inert-gas stripping, vacuum-steam stripping, and extraction with a second solvent. Vacuum-steam stripping is a particularly attractive choice for removal of MIBK; this reinforces the utility of MIBK as a solvent. The optimal temperature for vacuum stripping is generally the temperature of the extraction operation, which in turn is related to the effect of temperature on K/sub D/. Values of K/sub D/ for phenol-water-MIBK were determined at 30, 50, and 75/sup 0/C, and were found to decrease with increasing temperature at all concentrations.

  5. Towards ultra-fast solvent evaporation, the development of a computer controlled solvent vapor annealing chamber

    NASA Astrophysics Data System (ADS)

    Nelson, Gunnar; Wong, J.; Drapes, C.; Grant, M.; Baruth, A.

    Despite the promise of cheap and fast nanoscale ordering of block polymer thin films via solvent vapor annealing, a standardized, scalable production scheme remains elusive. Solvent vapor annealing exposes a nano-thin film to the vapors of one or more solvents with the goal of forming a swollen and mobile state to direct the self-assembly process by tuning surface energies and mediating unfavorable chain interactions. We have shown that optimized annealing conditions, where kinetic and thermal properties for crystal growth are extremely fast (<1s), exist at solvent concentrations just below the order-disorder transition of the film. However, when investigating the propagation of a given morphology into the bulk of a film during drying, the role of solvent evaporation comes under great scrutiny. During this process, the film undergoes a competition between two fronts; phase separation and kinetic trapping. Recent results in both theory and experiment point toward this critical element in controlling the resultant morphologies; however, no current method includes a controllable solvent evaporation rate at ultra-fast time scales. We report on a computer-controlled, pneumatically actuated chamber that provides control over solvent evaporation down to 15 ms. Furthermore, in situ spectral reflectance monitors solvent concentration with 10 ms temporal resolution and reveals several possible evaporation trajectories, ranging from linear to exponential to logarithmic. Funded by Dr. Randolph Ferlic Summer Research Scholarship and NASA Nebraska Space Grant.

  6. Changes in psychological performances of solvent-poisoned and solvent-exposed workers

    SciTech Connect

    Lindstroem, K.

    1980-01-01

    The changes in psychological performances associated with long-term exposure to organic solvents and solvent mixtures were studied in a group of 56 male workers diagnosed as having an occupational disease caused by solvents. Their mean duration of exposure was 9.1 +/- SD 8.3 years, and they were exposed mainly to halogenated and aromatic hydrocarbons and to mixtures of paint solvents. The psychological performances of these solvent-exposed patients were compared with those of 98 styrene-exposed workers and a nonexposed group of 43 construction workers. The applied psychological test variables were factor analyzed, before other statistical analysis, in order to clarify what they measured in the present study. The solvent-exposed group was characterized by a decline in visuomotor performance and decreased freedom from distractibility. The poor visuomotor performances were also related to the long duration of solvent exposure in this group of patients. The index applied for the exposure level revealed no significant relationships to psychological performances among the solvent-exposed patients. The psychological performances of the styrene-exposed group differed only very slightly from those of the nonexposed workers.

  7. Chlorinated solvent replacements recycle/recovery review report

    SciTech Connect

    Beal, M.; Hsu, D.; McAtee, R.E.; Weidner, J.R.; Berg, L.; McCandless, F.P.; Waltari, S.; Peterson, C.

    1992-08-01

    This report is a literature review of waste solvents recycle/recovery methods and shows the results of solvent separations using membrane and distillation technologies. The experimental solvent recovery methods were conducted on solvent replacements for chlorinated solvents at Montana State University. The literature review covers waste solvents separation using distillation, membranes decantation, filtration, carbon adsorption, solvent extraction, and other vapor-phase separation techniques. The results of this study identify solvent distillation methods as the most common separation technique. The alternative separation methods typically supplement distillation. The study shows the need for industries to identify waste solvent disposal methods and investigate the economics of waste solvent recycling as a possible waste reduction method.

  8. Development of deep eutectic solvents applied in extraction and separation.

    PubMed

    Li, Xiaoxia; Row, Kyung Ho

    2016-09-01

    Deep eutectic solvents, as an alternative to ionic liquids, have greener credentials than ionic liquids, and have attracted considerable attention in related chemical research. Deep eutectic solvents have attracted increasing attention in chemistry for the extraction and separation of various target compounds from natural products. This review highlights the preparation of deep eutectic solvents, unique properties of deep eutectic solvents, and synthesis of deep-eutectic-solvent-based materials. On the other hand, application in the extraction and separation of deep eutectic solvents is also included in this report. In this paper, the available data and references in this field are reviewed to summarize the applications and developments of deep eutectic solvents. Based on the development of deep eutectic solvents, an exploitation of new deep eutectic solvents and deep eutectic solvents-based materials is expected to diversify into extraction and separation.

  9. Ion Exchange and Solvent Extraction: Supramolecular Aspects of Solvent Exchange Volume 21

    SciTech Connect

    Gloe, Karsten; Tasker, Peter A; Oshima, Tatsuya; Watarai, Hitoshi; Nilsson, Mikael

    2013-01-01

    inverse micelles swollen with water molecules. Extraction systems involving long-chain cations such as alkylammonium species or long-chain anions such as sulfonates or carboxylates proved especially prone to extensive aggregate formation. The related phenomenon of third-phase formation in SX systems, long misunderstood, is now yielding to spectroscopic and scattering techniques showing extensive long-range organization. Over the last 50 years, tools for studying the structure and thermodynamics of aggregation have grown increasingly sophisticated, leading to a rich and detailed understanding of what we can now recognize as SC phenomena in SX. In the 1970s and 1980s, the rapid growth of SC elicited a paradigm shift in SX. The influence of SC principles had two major effects on the course of SX research. First, it provided a framework for understanding the supramolecular behavior that was already well appreciated in the field of SX, though earlier without the SC terminology. Second, it provided the conceptual tools to control supramolecular behavior in SX, direct it for intended functionality, and to simplify it. Extraction by designed reagents has been steadily progressing ever since, with commercial applications emerging to successfully validate this approach. With the discovery of crown ethers in the late 1960s, the advancement of extractant design has fruitfully employed the concept of inclusion. While considerable initial progress occurred with such molecules, especially because of their affinity and selectivity for alkali and alkaline earth metals, other molecular platforms such as calixarenes have proven more versatile. Multidentate receptors for partial to full inclusion of cations, anions, ion pairs, as well as neutral species, have now become commonplace for selective extraction. This volume of Ion Exchange and Solvent Extraction examines how the principles of SC are being employed both in advancing the design of new highly selective SX systems and in

  10. Solvent effects on chemical processes. 8. Demethylation kinetics of aspartame in binary aqueous-organic solvents.

    PubMed

    Skwierczynski, R D; Connors, K A

    1994-12-01

    The kinetics of demethylation of aspartame were studied in binary aqueous-organic solvent mixtures at 25 degrees C under two solution conditions, namely 1.0 M HCl (pH 0.28 in water) and carbonate buffer (pH 10.1 in water). Under these conditions solvent effects on the acid dissociation constants of aspartame do not complicate the interpretation of the kinetics. The organic cosolvents were acetone, acetonitrile, dimethyl sulfoxide, dioxane, tetrahydrofuran, and methanol. The observed kinetic solvent effects were modest in magnitude, not exceeding a factor of 3 in rate constant, relative to the fully aqueous solution. The rate changes included both increases and decreases, and in some solvent mixtures extrema were observed. It is concluded that at least two contributory factors, identified as an electrostatic (dielectric constant) effect and a solvation effect, must be operating to produce the observed kinetic solvent effects.

  11. Direct photolithography of perfluoropolyethers for solvent-resistant microfluidics.

    PubMed

    Vitale, Alessandra; Quaglio, Marzia; Marasso, Simone L; Chiodoni, Angelica; Cocuzza, Matteo; Bongiovanni, Roberta

    2013-12-17

    In this work, photocurable perfluoropolyethers (PFPEs) have been used for the fabrication of microfluidic devices by a direct photolithographic process. During this mask-assisted photopolymerization technique, the material is directly photopolymerized in the presence of a mask, avoiding the use of a master. We demonstrate the high level of control in transferring micropattern features with high density, a minimum transferred size of 15 μm, a high aspect ratio (at least up to 6.5), and complex shapes useful for microfluidic applications. Moreover, we successfully apply this technology to fabricate sealed devices; the fabrication time scale for the overall process is around 5 min. The devices are able to withstand a flow pressure of up to 3.8 bar, as required for most microfluidics. Finally, the devices are tested with a model reaction employing organic solvents.

  12. 40 CFR Table 3 to Subpart Nnnn of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Default Organic HAP Mass Fraction for...—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in... formulation data. Solvent/solvent blend CAS. No. Average organic HAP mass fraction Typical organic...

  13. 40 CFR Table 6 to Subpart Kkkk of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the.... Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP, percent by mass...

  14. 40 CFR Table 4 to Subpart Oooo of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Default Organic HAP Mass Fraction for... 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction... formulation data. Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP,...

  15. 40 CFR Table 3 to Subpart Rrrr of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the...: Solvent/Solvent blend CAS. No. Average organic HAP mass fraction Typical organic HAP, percent by mass...

  16. 40 CFR Table 5 to Subpart Qqqq of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Default Organic HAP Mass Fraction for...—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in... formulation data. Solvent/solvent blend CAS. No. Average organic HAP mass fraction Typical organic...

  17. 40 CFR Table 5 to Subpart Qqqq of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Default Organic HAP Mass Fraction for...—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in... formulation data. Solvent/solvent blend CAS. No. Average organic HAP mass fraction Typical organic...

  18. 40 CFR Table 3 to Subpart Nnnn of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Default Organic HAP Mass Fraction for...—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in... formulation data. Solvent/solvent blend CAS. No. Average organic HAP mass fraction Typical organic...

  19. 40 CFR Table 3 to Subpart IIIi of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Default Organic HAP Mass Fraction for... of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass... manufacturer's formulation data Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical...

  20. 40 CFR Table 6 to Subpart Kkkk of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the.... Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP, percent by mass...

  1. 40 CFR Table 6 to Subpart Kkkk of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the.... Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP, percent by mass...

  2. 40 CFR Table 3 to Subpart Rrrr of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the...: Solvent/Solvent blend CAS. No. Average organic HAP mass fraction Typical organic HAP, percent by mass...

  3. 40 CFR Table 4 to Subpart Oooo of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for... 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction... formulation data. Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP,...

  4. 40 CFR Table 3 to Subpart IIIi of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the... Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP, percent by mass...

  5. 40 CFR Table 3 to Subpart Nnnn of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Default Organic HAP Mass Fraction for...—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in... formulation data. Solvent/solvent blend CAS. No. Average organic HAP mass fraction Typical organic...

  6. 40 CFR Table 3 to Subpart IIIi of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Default Organic HAP Mass Fraction for... of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass... manufacturer's formulation data Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical...

  7. 40 CFR Table 3 to Subpart IIIi of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the... Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP, percent by mass...

  8. 40 CFR Table 3 to Subpart IIIi of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Default Organic HAP Mass Fraction for... of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass... manufacturer's formulation data Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical...

  9. 40 CFR Table 5 to Subpart Qqqq of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Default Organic HAP Mass Fraction for... HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the.... Solvent/solvent blend CAS. No. Average organic HAP mass fraction Typical organic HAP, percent by mass...

  10. Photochemistry of 5-aminoquinoline in protic and aprotic solvents.

    PubMed

    Bridhkoti, Jagat P; Mishra, Hirdyesh; Joshi, H C; Pant, Sanjay

    2011-08-01

    Photophysical properties of 5-aminoquinoline (5AQ) have been investigated in various non-polar and polar (protic and aprotic) solvents using steady state and time resolved fluorescence. In aprotic solvents, the spectral maxima depend on the polarity. However, in protic solvents both the fluorescence intensity as well decay time show decrease depending on the hydrogen bonding ability of the solvent. The results suggest that photochemistry 5AQ is quite sensitive towards the polarity as well as protic character of the solvent.

  11. Effect of solvents on physical properties and release characteristics of monolithic hydroxypropylmethylcellulose matrix granules and tablets.

    PubMed

    Cao, Qing-Ri; Choi, Yun-Woong; Cui, Jing-Hao; Lee, Beom-Jin

    2005-04-01

    Effect of solvents on physical characteristics and release characteristics of monolithic acetaminophen (APAP) hydroxypropylmethylcellulose (HPMC) matrix granules and tablets were examined. Various types and amounts of solvents were employed for granulation and cOAting. APAP and other excipients were mixed and were then wet-granulated in a high-speed mixer. The dried granules were then directly compressed and film-coated with low viscosity grade HPMC. As the amount of water increased, the size of granules also increased, showing more spherical and regular shape. However, manufacturing problems such as capping and lamination in tableting occurred when water was used alone as a granulating solvent. The physical properties of HPMC matrix granules were not affected by the batch size. The initial release rate as well as the amount of APAP dissolved had a tendency to decrease as the water level increased. Addition of nonaqueous solvent like ethanol to water resulted in good physical properties of granules. When compared to water/ethanol as a coating solvent, the release rate of film-coated HPMC matrix tablets was more sensitive to the conditions of coating and drying in methylene chloride/ethanol. Most of all, monolithic HPMC matrix tablet when granulated in ethanol/water showed dual release with about 50% drug release immediately within few minutes followed by extended release. It was evident that the type and amount of solvents (mainly water and ethanol) were very important for wet granulation and film-coating of monolithic HPMC matrix tablet, because the plastic deforming and fragmenting properties of material were changed by the different strengths of the different solvents. PMID:15918526

  12. Hazardous Solvent Substitution Data System tutorial

    SciTech Connect

    Twitchell, K.E.; Skinner, N.L.

    1993-07-01

    This manual is the tutorial for the Hazardous Solvent Substitution Data System (HSSDS), an online, comprehensive system of information on alternatives to hazardous solvents and related subjects. The HSSDS data base contains product information, material safety data sheets, toxicity reports, usage reports, biodegradable data, product chemical element lists, and background information on solvents. HSSDS use TOPIC{reg_sign} to search for information based on a query defined by the user. TOPIC provides a full text retrieval of unstructured source documents. In this tutorial, a series of lessons is provided that guides the user through basic steps common to most queries performed with HSSDS. Instructions are provided for both window-based and character-based applications.

  13. Employment Impact of Electronic Business.

    ERIC Educational Resources Information Center

    Hecker, Daniel E.

    2001-01-01

    Electronic business is stimulating employment in some sectors across industries, such as computer-related and customer service occupations, and diminishing employment in others, such as administrative support and marketing/sales. Similarly, employment impacts will vary by industry. (Contains 56 notes and references.) (SK)

  14. Employment Initiatives. Second Year Report.

    ERIC Educational Resources Information Center

    Maryland State Dept. of Human Resources, Baltimore.

    During its second year, Maryland's Employment Initiatives (EI) program continued to help Aid for Dependent Children applicants and recipients obtain unsubsidized employment. It provided employment and training opportunities to Work Incentive Demonstration Program participants at two sites: Baltimore City (OPTIONS) and Wicomico County (Basic…

  15. Employment Discrimination in Higher Education.

    ERIC Educational Resources Information Center

    Lee, Barbara A.

    1999-01-01

    Reviewed academic employment discrimination cases decided in 1998. Concludes that such cases added little to civil rights jurisprudence, but demonstrated the frustration felt by many over the fact that federal employment discrimination statures were not designed with universities in mind. The complexity of academic employment decisions ensures…

  16. Effect of casting solvent on crystallinity of ondansetron in transdermal films.

    PubMed

    Pattnaik, Satyanarayan; Swain, Kalpana; Mallick, Subrata; Lin, Zhiqun

    2011-03-15

    The purpose of the present investigation is to assess the influence of casting solvent on crystallinity of ondansetron hydrochloride in transdermal polymeric matrix films fabricated using povidone and ethyl cellulose as matrix forming polymers. Various casting solvents like chloroform (CHL), dichloromethane (DCM), methanol (MET); and mixture of chloroform and ethanol (C-ETH) were used for fabrication of the transdermal films. Analytical tools like scanning electron microscopy (SEM), X-ray diffraction (XRD) studies, differential scanning calorimetry (DSC), etc. were utilized to characterize the crystalline state of ondansetron in the film. Recrystallisation was observed in all the transdermal films fabricated using the casting solvents other than chloroform. Long thin slab-looking, long wire-like or spherulite-looking crystals with beautiful impinged boundaries were observed in SEM. Moreover, XRD revealed no crystalline peaks of ondansetron hydrochloride in the transdermal films prepared using chloroform as casting solvent. The significantly decreased intensity and sharpness of the DSC endothermic peaks corresponding to the melting point of ondansetron in the formulation (specifically in CHL) indicated partial dissolution of ondansetron crystals in the polymeric films. The employed analytical tools suggested chloroform as a preferred casting solvent with minimum or practically absence of recrystallization indicating a relatively amorphous state of ondansetron in transdermal films. PMID:21237257

  17. Solvent-Dictated Lithium Sulfur Redox Reactions: An Operando UV-vis Spectroscopic Study.

    PubMed

    Zou, Qingli; Lu, Yi-Chun

    2016-04-21

    Fundamental understanding of solvent's influence on Li-S redox reactions is required for rational design of electrolyte for Li-S batteries. Here we employ operando UV-vis spectroscopy to reveal that Li-S redox reactions in high-donor-number solvents, for example, dimethyl sulfoxide (DMSO), undergo multiple electrochemical and chemical reactions involving S8(2-), S6(2-), S4(2-), and S3(•-), where S3(•-) is the most stable and dominant reaction intermediate. In low-donor-number solvents, for example, 1,3-dioxolane:1,2-dimethoxyethane, the dominant reaction intermediate, is found to be S4(2-). The stability of these main polysulfide intermediates determines the reaction rates of the disproportionation/dissociation/recombination of polysulfides and thereby affects the reaction rates of the Li-S batteries. As an example, we show that dimethylformamide, a high-donor-number solvent, which exhibits stronger stabilization of S3(•-) compared with DMSO, significantly reduces Li-S cell polarization compared with DMSO. Our study reveals solvent-dependent Li-S reaction pathways and highlights the role of polysulfide stability in the efficiency of Li-S batteries. PMID:27050386

  18. Recovery of isopropyl alcohol from waste solvent of a semiconductor plant.

    PubMed

    Lin, Sheng H; Wang, Chuen S

    2004-01-30

    An important waste solvent generated in the semiconductor manufacturing process was characterized by high isopropyl alcohol (IPA) concentration over 65%, other organic pollutants and strong color. Because of these characteristics, IPA recovery was deemed as a logic choice for tackling this waste solvent. In the present work, an integrated method consisting of air stripping in conjunction with condensation and packed activated carbon fiber (ACF) adsorption for dealing with this waste solvent. The air stripping with proper stripping temperature control was employed to remove IPA from the waste solvent and the IPA vapor in the gas mixture was condensed out in a side condenser. The residual IPA remaining in the gas mixture exiting the side condenser was efficiently removed in a packed ACF column. The air stripping with condensation was able to recover up to 93% of total IPA in the initial waste solvent. The residual IPA in the gas mixture, representing less than 3% of the initial IPA, was efficiently captured in the packed ACF column. Experimental tests were conducted to examine the performances of each unit and to identify the optimum operating conditions. Theoretical modeling of the experimental IPA breakthrough curves was also undertaken using a macroscopic model. The verified breakthrough model significantly facilitates the adsorption column design. The recovered IPA was found to be of high purity and could be considered for reuse.

  19. Ionic liquid solutions as extractive solvents for value-added compounds from biomass

    PubMed Central

    Passos, Helena; Freire, Mara G.; Coutinho, João A. P.

    2014-01-01

    In the past few years, the number of studies regarding the application of ionic liquids (ILs) as alternative solvents to extract value-added compounds from biomass has been growing. Based on an extended compilation and analysis of the data hitherto reported, the main objective of this review is to provide an overview on the use of ILs and their mixtures with molecular solvents for the extraction of value-added compounds present in natural sources. The ILs (or IL solutions) investigated as solvents for the extraction of natural compounds, such as alkaloids, flavonoids, terpenoids, lipids, among others, are outlined. The extraction techniques employed, namely solid–liquid extraction, and microwave-assisted and ultrasound-assisted extractions, are emphasized and discussed in terms of extraction yields and purification factors. Furthermore, the evaluation of the IL chemical structure and the optimization of the process conditions (IL concentration, temperature, biomass–solvent ratio, etc.) are critically addressed. Major conclusions on the role of the ILs towards the extraction mechanisms and improved extraction yields are additionally provided. The isolation and recovery procedures of the value-added compounds are ascertained as well as some scattered strategies already reported for the IL solvent recovery and reusability. Finally, a critical analysis on the economic impact versus the extraction performance of IL-based methodologies was also carried out and is here presented and discussed. PMID:25516718

  20. Neurologic effects of solvents in older adults. (UW retired worker study). Final performance report

    SciTech Connect

    Daniell, W.E.

    1993-11-12

    The possibility that previous occupational exposure to solvents might be associated with clinically significant neurological dysfunction in older adults was investigated in a cross-sectional study. Subjects included 67 painters, 22 aerospace painters and fuel cell sealers, and a comparison group of 126 carpenters. All subjects had retired from regular employment at least 1 year prior to the study. As measured by semiquantitative exposure index, the cumulative histories of lifetime occupational solvent exposure were on the average comparable in the two exposed study groups, painters and aerospace workers. The carpenters differed from the other groups in solvent exposure by several orders of magnitude. The painters had a significantly higher history of consuming alcoholic beverages than did the other two study groups. The painters had a significantly higher score on the Beck Depression Inventory, a measure of current depressive symptoms. The painters reported significantly more general neurologic symptoms than did the other two groups. The aerospace workers showed much greater evidence of possible adverse effects from former solvent exposure on current neuropsychological function than did the painters when determined by reasoning and memory tests, memory visual motor speed and motor tests. No evidence of persistent effects on liver or renal excretory function was seen in solvent exposed subjects.

  1. High-repetition-rate, narrow-band dye lasers with water as a solvent for dyes

    NASA Astrophysics Data System (ADS)

    Ray, Alok K.; Sinha, Sucharita; Kundu, Soumitra; Kumar, Sasi; Nair, Sivagiriyal Karunakaran Sreenivasan; Pal, Tamal; Dasgupta, Kamalesh

    2002-03-01

    The performance of a copper vapor laser-pumped narrow-band dye laser in oscillator-amplifier configuration with water-based binary mixture solvents is described. Although oscillator efficiency in water-surfactant (sodium lauryl sulfate) solvent was comparable with that that employed pure ethanolic solvent, amplifier efficiency was found to be lower. Experiments that were carried out with vertically polarized pump beams and either horizontally or vertically polarized signal beams show that, in case of both the pump and signal having orthogonal polarization (horizontal) and same polarization (vertical), the extraction efficiency for both ethanolic and water-micelle media increased substantially from 15.7% to 18.5% and from 10% to 12.5%, respectively. However, the relative difference remained nearly the same, indicating that a slower orientational diffusion of excited dye molecules in a micellar medium is not responsible for a decrease in amplifier efficiency. Amplifier efficiency comparable with that containing ethanolic dye solutions could be obtained with a binary solvent that comprises a mixture of water and about 30% n-propanol. The performances of two efficient dyes, Rhodamine-6G and Kiton Red S, using water-based solvents were studied.

  2. Solvent-Dictated Lithium Sulfur Redox Reactions: An Operando UV-vis Spectroscopic Study.

    PubMed

    Zou, Qingli; Lu, Yi-Chun

    2016-04-21

    Fundamental understanding of solvent's influence on Li-S redox reactions is required for rational design of electrolyte for Li-S batteries. Here we employ operando UV-vis spectroscopy to reveal that Li-S redox reactions in high-donor-number solvents, for example, dimethyl sulfoxide (DMSO), undergo multiple electrochemical and chemical reactions involving S8(2-), S6(2-), S4(2-), and S3(•-), where S3(•-) is the most stable and dominant reaction intermediate. In low-donor-number solvents, for example, 1,3-dioxolane:1,2-dimethoxyethane, the dominant reaction intermediate, is found to be S4(2-). The stability of these main polysulfide intermediates determines the reaction rates of the disproportionation/dissociation/recombination of polysulfides and thereby affects the reaction rates of the Li-S batteries. As an example, we show that dimethylformamide, a high-donor-number solvent, which exhibits stronger stabilization of S3(•-) compared with DMSO, significantly reduces Li-S cell polarization compared with DMSO. Our study reveals solvent-dependent Li-S reaction pathways and highlights the role of polysulfide stability in the efficiency of Li-S batteries.

  3. Measurement of thickness and composition of a solvent film on a bubble.

    PubMed

    Tarkan, H M; Gélinas, S; Finch, J A

    2006-05-15

    Solvent-coated air bubbles in the air-assisted solvent extraction (AASX) process achieve the dual role of high solvent specific surface area and ease of phase separation. The properties and thickness of the solvent film control the process. As an approach to the study, the layer interferometry (in the UV-vis region) and FT-IR spectroscopy were used to measure the time dependent thickness and chemical composition, respectively, of a film formed by blowing an air bubble in kerosene-based solvents. The film was stabilized by the presence of 1.5 ppm silicone oil, as employed in AASX. The film appears to comprise two layers; an outer layer of almost constant thickness and an inner layer which decreased in thickness with time. The latter is considered relevant to AASX. Generally, the initial thickness was approximately 3 microm which decreased over several minutes to a final rupture thickness of 500 nm. The initial thickness is of the order determined indirectly. The chemical composition of the layer did not change with time.

  4. Translational diffusion in mixtures of imidazolium ILs with polar aprotic molecular solvents.

    PubMed

    Marekha, Bogdan A; Kalugin, Oleg N; Bria, Marc; Buchner, Richard; Idrissi, Abdenacer

    2014-05-22

    Self-diffusion coefficients of cations and solvent molecules were determined with (1)H NMR in mixtures of 1-n-butyl-3-methylimidazolium (Bmim(+)) tetrafluoroborate (BF4(-)), hexafluorophosphate (PF6(-)), trifluoromethanesulfonate (TfO(-)), and bis(trifluoromethylsulfonyl)imide (TFSI(-)) with acetonitrile (AN), γ-butyrolactone (γ-BL), and propylene carbonate (PC) over the entire composition range at 300 K. The relative diffusivities of solvent molecules to cations as a function of concentration were found to depend on the solvent but not on the anion (i.e., IL). In all cases the values exhibit a plateau at low IL content (x(IL) < 0.2) and then increase steeply (AN), moderately (γ-BL), or negligibly (PC) at higher IL concentrations. This behavior was related to the different solvation patterns in the employed solvents. In BmimPF6-based systems, anionic diffusivities were followed via (31)P nuclei and found to be higher than the corresponding cation values in IL-poor systems and lower in the IL-rich region. The inversion point of relative ionic diffusivities was found around equimolar composition and does not depend on the solvent. At this point, a distinct change in the ion-diffusion mechanism appears to take place.

  5. Dispersion and coalescence of oil droplets by ultrasound and application for solvent extraction of gallium

    NASA Astrophysics Data System (ADS)

    Yasuda, Keiji; Thanh Nguyen, Tam; Okura, Risa; Nakayama, Shingo; Asakura, Yoshiyuki; Jin, Jiye

    2015-07-01

    To improve the performance of solvent extraction of rare metals, the effects of ultrasonic and organic solvent conditions on the demulsification of emulsions were examined. Optimized conditions were adopted in the solvent extraction of gallium by ultrasonic irradiation. As organic solvents, chloroform, 1,2-dichloromethane, p-bromotoluene, bromobenzene, and 1,2-dibromoethane were employed. Emulsification was carried out using a horn-type transducer at 20 kHz. Demulsification was performed with plate-type transducers at 1.0-4.8 MHz. The demulsification time decreased with increasing ultrasonic frequency and power because the primary and secondary acoustic forces of droplets become stronger. Inclining the vessel shortened the demulsification time. In the case of chloroform at a low solution pH, the demulsification time was shortest since the zeta potential of droplets was close to zero. The sequential ultrasonic irradiation at 20 kHz and 4.8 MHz greatly shortens the operation time needed for solvent extraction of gallium from an aqueous solution.

  6. Solubility of C[sub 60] in a variety of solvents

    SciTech Connect

    Ruoff, R.S.; Tse, D.S.; Malhotra, R.; Lorents, D.C. )

    1993-04-01

    The room temperature solubility of pure C[sub 60] has been determined in 47 solvents. The solubilities cover a wide range, from 0.01 mg/mL in methanol to 50 mg/mL in 1-chloronaphthalene. The solubilities in CS[sub 2], toluene, and hexane, three of the commonly employed solvents, are 7.9, 2.8, and 0.04 mg/mL, respectively. An examination of the solubilities of C[sub 60] as a function of the solvent properties such as index of refraction, dielectric constant, molecular size, Hildebrand solubility parameter, and H-bonding strength reaffirms the century-old principle like dissolves like. No single solvent parameter can uniformly predict the solubility of C[sub 60], but a composite picture of solvents with high solubility for C[sub 60] emerges: large index of refraction, dielectric constant around 4, large molecular volume, Hildebrand solubility parameter equal to 10 cal[sup 1/2] cm[sup [minus]3/2], and tendency to act as a moderate strength nucleophile. 18 refs., 4 figs., 1 tab.

  7. Recovery of isopropyl alcohol from waste solvent of a semiconductor plant.

    PubMed

    Lin, Sheng H; Wang, Chuen S

    2004-01-30

    An important waste solvent generated in the semiconductor manufacturing process was characterized by high isopropyl alcohol (IPA) concentration over 65%, other organic pollutants and strong color. Because of these characteristics, IPA recovery was deemed as a logic choice for tackling this waste solvent. In the present work, an integrated method consisting of air stripping in conjunction with condensation and packed activated carbon fiber (ACF) adsorption for dealing with this waste solvent. The air stripping with proper stripping temperature control was employed to remove IPA from the waste solvent and the IPA vapor in the gas mixture was condensed out in a side condenser. The residual IPA remaining in the gas mixture exiting the side condenser was efficiently removed in a packed ACF column. The air stripping with condensation was able to recover up to 93% of total IPA in the initial waste solvent. The residual IPA in the gas mixture, representing less than 3% of the initial IPA, was efficiently captured in the packed ACF column. Experimental tests were conducted to examine the performances of each unit and to identify the optimum operating conditions. Theoretical modeling of the experimental IPA breakthrough curves was also undertaken using a macroscopic model. The verified breakthrough model significantly facilitates the adsorption column design. The recovered IPA was found to be of high purity and could be considered for reuse. PMID:15177106

  8. Solvent-assisted lipid bilayer formation on silicon dioxide and gold.

    PubMed

    Tabaei, Seyed R; Choi, Jae-Hyeok; Haw Zan, Goh; Zhdanov, Vladimir P; Cho, Nam-Joon

    2014-09-01

    Planar lipid bilayers on solid supports mimic the fundamental structure of biological membranes and can be investigated using a wide range of surface-sensitive techniques. Despite these advantages, planar bilayer fabrication is challenging, and there are no simple universal methods to form such bilayers on diverse material substrates. One of the novel methods recently proposed and proven to form a planar bilayer on silicon dioxide involves lipid deposition in organic solvent and solvent exchange to influence the phase of adsorbed lipids. To scrutinize the specifics of this solvent-assisted lipid bilayer (SALB) formation method and clarify the limits of its applicability, we have developed a simplified, continuous solvent-exchange version to form planar bilayers on silicon dioxide, gold, and alkanethiol-coated gold (in the latter case, a lipid monolayer is formed to yield a hybrid bilayer) and varied the type of organic solvent and rate of solvent exchange. By tracking the SALB formation process with simultaneous quartz crystal microbalance-dissipation (QCM-D) and ellipsometry, it was determined that the acoustic, optical, and hydration masses along with the acoustic and optical thicknesses, measured at the end of the process, are comparable to those observed by employing conventional fabrication methods (e.g., vesicle fusion). As shown by QCM-D measurements, the obtained planar bilayers are highly resistant to protein adsorption, and several, but not all, water-miscible organic solvents could be successfully used in the SALB procedure, with isopropanol yielding particularly high-quality bilayers. In addition, fluorescence recovery after photobleaching (FRAP) measurements demonstrated that the coefficient of lateral lipid diffusion in the fabricated bilayers corresponds to that measured earlier in the planar bilayers formed by vesicle fusion. With increasing rate of solvent exchange, it was also observed that the bilayer became incomplete and a phenomenological

  9. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1990-11-01

    Research continued on the swelling of coal. Changes in the size and number distribution of the accessible regions in five Argonne Premium Coal Samples (APCS No.3, No.4, No.5, No.6, and No.8) upon swelling with the solvents, cyclohexane, toluene, nitrobenzene and pyridine were examined by an EPR spin probe method. It was found that as the basicity of the solvent increased the number and length of the cylindrical pores increased with decreasing rank. The number of cylindrical pores also increased with oxygen content (with decreasing rank) suggesting a destruction of the hydrogen-bond network upon swelling with pyridine. 6 refs.

  10. Catalog solvent extraction: anticipate process adjustments

    SciTech Connect

    Campbell, S.G.; Brass, E.A.; Brown, S.J.; Geeting, M.W.

    2008-07-01

    The Modular Caustic-Side Solvent Extraction Unit (MCU) utilizes commercially available centrifugal contactors to facilitate removal of radioactive cesium from highly alkaline salt solutions. During the fabrication of the contactor assembly, demonstrations revealed a higher propensity for foaming than was initially expected. A task team performed a series of single-phase experiments that revealed that the shape of the bottom vanes and the outer diameter of those vanes are key to the successful deployment of commercial contactors in the Caustic-Side Solvent Extraction Process. (authors)

  11. Copper leaching, solvent extraction, and electrowinning technology

    SciTech Connect

    Jergensen, G.V. II

    1999-07-01

    This volume recognizes the growing role of solvent extraction and electrowinning technology in the global copper business. This process is an efficient and cost effective way to extract copper. This proceedings documents the present status of the SX-EW business. It represents a substantial body of historical, scientific, engineering, and commercial information regarding the growth and application of the technology. Sections include: the business and technology of SX-EW, theory and practice of copper leaching, theory and practice of tankhouse operations, and theory and practice of solvent extraction.

  12. Solvent-resistant microporous polymide membranes

    DOEpatents

    Miller, W.K.; McCray, S.B.; Friesen, D.T.

    1998-03-10

    An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

  13. Solvent-resistant microporous polymide membranes

    DOEpatents

    Miller, Warren K.; McCray, Scott B.; Friesen, Dwayne T.

    1998-01-01

    An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

  14. A multi-step solvent-free mechanochemical route to indium(iii) complexes.

    PubMed

    Wang, Jingyi; Ganguly, Rakesh; Yongxin, Li; Díaz, Jesus; Soo, Han Sen; García, Felipe

    2016-05-10

    Mechanochemistry is well-established in the solid-phase synthesis of inorganic materials but has rarely been employed for molecular syntheses. In recent years, there has been nascent interest in 'greener' synthetic methods with less solvent, higher yields, and shorter reaction times being especially appealing to the fine chemicals and inorganic catalyst industries. Herein, we demonstrate that main-group indium(iii) complexes featuring bis(imino)acenaphthene (BIAN) ligands are readily accessible through a mechanochemical milling approach. The synthetic methodology reported herein not only bypasses the use of large solvent quantities and transition metal reagents for ligand synthesis, but also reduces reaction times dramatically. These new main-group complexes exhibit the potential to be reduced to indium(i) compounds, which may be employed as photosensitizers in organic catalyses and functional materials. PMID:27112317

  15. A multi-step solvent-free mechanochemical route to indium(iii) complexes.

    PubMed

    Wang, Jingyi; Ganguly, Rakesh; Yongxin, Li; Díaz, Jesus; Soo, Han Sen; García, Felipe

    2016-05-10

    Mechanochemistry is well-established in the solid-phase synthesis of inorganic materials but has rarely been employed for molecular syntheses. In recent years, there has been nascent interest in 'greener' synthetic methods with less solvent, higher yields, and shorter reaction times being especially appealing to the fine chemicals and inorganic catalyst industries. Herein, we demonstrate that main-group indium(iii) complexes featuring bis(imino)acenaphthene (BIAN) ligands are readily accessible through a mechanochemical milling approach. The synthetic methodology reported herein not only bypasses the use of large solvent quantities and transition metal reagents for ligand synthesis, but also reduces reaction times dramatically. These new main-group complexes exhibit the potential to be reduced to indium(i) compounds, which may be employed as photosensitizers in organic catalyses and functional materials.

  16. Phase formation during supercritical solvent deashing of solvent-refined coal. Final report

    SciTech Connect

    Henry, J.D. Jr.; Verhoff, F.H.

    1982-11-01

    A constant volume high temperature - pressure phase contacting cell was used in conjunction with an x-ray measurement technique to experimentally determine the volumes of the phases that are formed when supercritical solvents are contacted with solvent refined coal. A material balance technique is used in conjunction with the x-ray data to determine the mass of the phases. The constant volume technique can be used to independently vary temperature and pressure. In addition to temperature pressure variation, the ratio of solvent to solvent refined coal was a major parameter in this investigation. Solvent/W. SRC ratios of 2, 3 and 4 were investigated. Experiments were conducted on the following five systems: Wilsonville Solvent Refined Coal (W. SRC) - Heptane, W. SRC - Toluene, W. SRC - Pyridine, Asphaltene - Toluene and Preasphaltene - Toluene. Pyridine dissolved virtually all of the solvent refined coal. Toluene dissolved intermediate quantities and Heptane dissolved the least. A solubility maximum was observed with the W. SRC - Toluene system. The maximum solubility occurred significantly below the critical point of toluene and at temperatures above the critical point, dissolved solutes were rejected. Qualitatively the same behavior was observed with the asphaltene - toluene system. Toluene did not dissolve preasphaltenes. The maximum solubility with the W. SRC - Toluene system was found to be pressure insensitive at a toluene/W. SRC ratio of 3:1. At a ratio of 4:1 the maximum solubility was more pressure sensitive. 50 figures, 45 tables.

  17. High power, solvent-free electrochemical double layer capacitors based on pyrrolidinium dicyanamide ionic liquids

    NASA Astrophysics Data System (ADS)

    Wolff, Christian; Jeong, Sangsik; Paillard, Elie; Balducci, Andrea; Passerini, Stefano

    2015-10-01

    In this manuscript are reported the synthesis and physicochemical characterization of low viscosity pyrrolidinium dicyanamide (DCA-) ionic liquids (ILs). Due to their high ionic conductivity, these fluorine-free, molecular solvent-free ILs are excellent candidates to be employed as electrolytes in electrochemical double layer capacitors (EDLCs). Tests of lab-scale prototypes reported herein show that DCA--based EDLCs display high power at room temperature as well as high cycling stability.

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

    SciTech Connect

    Smith, Tara E.; Scherman, Carl; Martin, David; Suggs, Patricia

    2015-01-14

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

  19. DEGRADED TBP SOLVENT REGENERATION TECHNOLOGY USING BUTYLAMINE AS A SOLVENT WASHING TO REDUCE SOLID SALT WASTE

    SciTech Connect

    Asakura, T.; Itoh, Y.; Hotoku, S.; Morita, Y.; Uchiyama, G.

    2003-02-27

    Normal butylamine compounds are studied as salt-free wash reagents for degraded solvent used in PUREX process in spent fuel reprocessing. The solvent wash tests were carried out with two types of butylamine compounds, n-butylamine oxalate and n-butylamine bicarbonate, by counter-current mode using a small size mixer-settler composed of two 4-stage wash steps. Di-n-butyl phosphoric acid (HDBP), the main degradation product from TBP, was removed from real degraded solvent with decontamination factor of 2.5 {approx} 7.9. The study on electrolytic decomposition of butylamine compounds was also conducted for waste treatment.

  20. Structure and Solvent Properties of Microemulsions

    ERIC Educational Resources Information Center

    Katz, Civia A.; Calzola, Zachary J.; Mbindyo, Jeremiah K. N.

    2008-01-01

    A microscale laboratory experiment to investigate the formation and utility of microemulsions is described. Microemulsions are technologically important fluids that can reduce the use of toxic organic solvents. In the experiment, students prepare a microemulsion and compare the solubility of sudan III dye in the microemulsion and in dodecane. They…

  1. Crystal growth in fused solvent systems

    NASA Technical Reports Server (NTRS)

    Ulrich, D. R.; Noone, M. J.; Spear, K. E.; White, W. B.; Henry, E. C.

    1973-01-01

    Research is reported on the growth of electronic ceramic single crystals from solution for the future growth of crystals in a microgravity environment. Work included growth from fused or glass solvents and aqueous solutions. Topics discussed include: crystal identification and selection; aqueous solution growth of triglycine sulphate (TGS); and characterization of TGS.

  2. Microbial responses to solvent and alcohol stress.

    PubMed

    Taylor, Mark; Tuffin, Marla; Burton, Stephanie; Eley, Kirstin; Cowan, Don

    2008-11-01

    Increasing fuel prices and doubts over the long-term availability of oil are currently major global concerns. Such concerns have led to national policies and objectives to develop microbially produced alcohols as fuel additives or substitutes. However, in South Africa this solution poses the further dilemma of sourcing a suitable fermentative carbohydrate that will not impact negatively on the availability of staple foods. The solution lies in the use of lignocellulosic materials, currently a waste product of the food and agriculture industries, which could be used in conjunction with a catabolically suitable production strain. In the pursuit of lignocellulosic biofuel production, conventional fermentation strains have been shown to have limited catabolic versatility. However, catabolically versatile engineered strains and novel isolates engineered with ethanologenic pathways have subsequently been shown to exhibit limitations in solvent tolerance, hindering their full potential as economically viable production strains. A considerable volume of research has been reported on the general cellular mechanisms and physiological responses to solvent shock as well as adaptive changes responsible for solvent tolerant phenotypes in mutant progeny. Here we review a number of the more common cell responses to solvents with particular focus on alcohol tolerance.

  3. Solvent treatment of coal for improved liquefaction

    DOEpatents

    Appell, Herbert R.; Narain, Nand K.; Utz, Bruce R.

    1986-05-06

    Increased liquefaction yield is obtained by pretreating a slurry of solid carbonaceous material and a liquid hydrocarbonaceous solvent at a temperature above 200.degree. C. but below 350.degree. C. for a period of 10 minutes to four hours prior to exposure to liquefaction temperatures.

  4. EXXON donor solvent coal liquefaction process

    NASA Technical Reports Server (NTRS)

    Epperly, W. R.; Swabb, L. E., Jr.; Tauton, J. W.

    1978-01-01

    A solvent coal liquefaction process to produce low-sulfur liquid products from a wide range of coals is described. An integrated program of laboratory and engineering research and development in conjunction with operation of a 250 T/D pilot plant is discussed.

  5. Selective solvent absorption in coal conversion

    SciTech Connect

    Larsen, J.W.; Lapucha, A.; Lazarov, L.; Amui, J.

    1992-04-01

    The objectives of this project are: (1) to determine the importance of the presence of added hydrogen donor compounds within the coal in the first stage of direct liquefaction processes; and (2) to determine the composition of the solvent absorbed by and present within the coal in the first stage of direct coal liquefaction.

  6. Solvent-Free Synthesis of Chalcones

    ERIC Educational Resources Information Center

    Palleros, Daniel R.

    2004-01-01

    The synthesis of twenty different chalcones in the absence of solvent is presented. The results indicated that out of the twenty different chalcones investigated seventeen can be obtained in a matter of minutes by mixing the corresponding benzaldehyde and acetophenone in the presence of solid NaOH in a mortar with pestle.

  7. REPLACING SOLVENT CLEANING WITH AQUEOUS CLEANING

    EPA Science Inventory

    The report documents actions taken by Robert Bosch Corp., Charleston, SC, in replacing the cleaning solvents 1, 1, 2- trichloro-1, 2, 2-trifluoroethane (CFC-113) and trichloroethylene (TCE) with aqueous solutions. Bosch has succeeded in eliminating all their CFC-113 use and so f...

  8. SOLVENT FREE CHEMICAL TRANSFORMATION USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes will be described that involve the exposure of neat reactants to microwave (MW) irradiation in the presence of supported reagents or catalysts on mineral oxides. Recent developments will be presented on the synthetic utility o...

  9. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1991-01-01

    The EPR-spin probe method was used to study the swelling of covalently cross-linked 2%, 4%, 6%, 8% and 12% polystyrene-divinyl benzene copolymers, used as models of APCS coal structural elements. The results were compared with swelling studies on APCS coals and confirmed results showing that coal was polymeric, that it had covalent cross-links increasing with rank, that it was structurally anisotropic, and that its swelling was anisotropic. The low temperature swelling of Argonne Premium Coal Samples using solvents of varying polarity was investigated. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities. The structural changes in coal pores that occur when APCS coal is dehydrated prior to swelling with polar solvents has been determined. These changes are different from those that occur in the absence of prior dehydration. Most impressive is the huge change that occurs in lignite coal (Beulah-Zap). It appears that this coal has collapsed upon dehydration preventing any spin probe from being trapped in the dehydrated lignite upon swelling. Various sized probes have been studied. A study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents has also been completed. A statistical analysis of the data has been completed to determine important trends in the data. 9 refs.

  10. Gas separation by composite solvent-swollen membranes

    DOEpatents

    Matson, S.L.; Lee, E.K.L.; Friesen, D.T.; Kelly, D.J.

    1989-04-25

    There is disclosed a composite immobilized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorus or sulfur atom, and having a boiling point of at least 100 C and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation. 3 figs.

  11. Gas separation by composite solvent-swollen membranes

    DOEpatents

    Matson, Stephen L.; Lee, Eric K. L.; Friesen, Dwayne T.; Kelly, Donald J.

    1989-01-01

    There is disclosed a composite immobulized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorous or sulfur atom, and having a boiling point of at least 100.degree. C. and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation.

  12. Studies on tropane alkaloid extraction by volatile organic solvents: dichloromethane vs. chloroform.

    PubMed

    El Jaber-Vazdekis, Nabil; Gutierrez-Nicolas, Fátima; Ravelo, Angel G; Zárate, Rafael

    2006-01-01

    In order to investigate the production of tropane alkaloids by hairy roots of Atropa baetica, transgenic for the gene h6h encoding the enzyme hyoscyamine 6beta-hydroxylase, solvent extraction with chloroform and with dichloromethane of the metabolites present in the liquid medium and in the root tissue was compared. The extraction of scopolamine from the liquid medium was equally effective with either solvent, giving maximum values of around 850 microg/flask. For the roots, three different extraction methods were employed: A, employing chloroform:methanol: (25%) ammonia (15:5:1) for initial extraction, followed by treatment with sulfuric acid and ammonia, and using chloroform for the final extraction and washes; B, as A but using dichloromethane for extraction and washes; and C, as B but substituting chloroform for dichloromethane in the extraction cocktail. Scopolamine was the most abundant metabolite (present in amounts of 3250-3525 microg/g dry weight) and presented similar extraction efficiencies with all of the extraction methods employed. The highest amounts of hyoscyamine and the intermediate 6beta-hydxoxyhyoscyamine were present on day 31 (800 and 975 microg/g dry weight, respectively) and no statistical differences between the three extraction methods employed were detected. This study confirms that, for the extraction of tropane alkaloids, dichloromethane can replace the commonly employed chloroform, the use of which incurs major health, security and regulation problems. PMID:16634287

  13. Ruthenium-catalyzed alkylation of indoles with tertiary amines by oxidation of a sp3 C-H bond and Lewis acid catalysis.

    PubMed

    Wang, Ming-Zhong; Zhou, Cong-Ying; Wong, Man-Kin; Che, Chi-Ming

    2010-05-17

    Ruthenium porphyrins (particularly [Ru(2,6-Cl(2)tpp)CO]; tpp=tetraphenylporphinato) and RuCl(3) can act as oxidation and/or Lewis acid catalysts for direct C-3 alkylation of indoles, giving the desired products in high yields (up to 82% based on 60-95% substrate conversions). These ruthenium compounds catalyze oxidative coupling reactions of a wide variety of anilines and indoles bearing electron-withdrawing or electron-donating substituents with high regioselectivity when using tBuOOH as an oxidant, resulting in the alkylation of N-arylindoles to 3-{[(N-aryl-N-alkyl)amino]methyl}indoles (yield: up to 82%, conversion: up to 95%) and the alkylation of N-alkyl or N-H indoles to 3-[p-(dialkylamino)benzyl]indoles (yield: up to 73%, conversion: up to 92%). A tentative reaction mechanism involving two pathways is proposed: an iminium ion intermediate may be generated by oxidation of an sp(3) C-H bond of the alkylated aniline by an oxoruthenium species; this iminium ion could then either be trapped by an N-arylindole (pathway A) or converted to formaldehyde, allowing a subsequent three-component coupling reaction of the in situ generated formaldehyde with an N-alkylindole and an aniline in the presence of a Lewis acid catalyst (pathway B). The results of deuterium-labeling experiments are consistent with the alkylation of N-alkylindoles via pathway B. The relative reaction rates of [Ru(2,6-Cl(2)tpp)CO]-catalyzed oxidative coupling reactions of 4-X-substituted N,N-dimethylanilines with N-phenylindole (using tBuOOH as oxidant), determined through competition experiments, correlate linearly with the substituent constants sigma (R(2)=0.989), giving a rho value of -1.09. This rho value and the magnitudes of the intra- and intermolecular deuterium isotope effects (k(H)/k(D)) suggest that electron transfer most likely occurs during the initial stage of the oxidation of 4-X-substituted N,N-dimethylanilines. Ruthenium-catalyzed three-component reaction of N-alkyl/N-H indoles, paraformaldehyde, and anilines gave 3-[p-(dialkylamino)benzyl]indoles in up to 82% yield (conversion: up to 95%).

  14. Ionic liquids and deep eutectic solvents in natural products research: mixtures of solids as extraction solvents.

    PubMed

    Dai, Yuntao; van Spronsen, Jaap; Witkamp, Geert-Jan; Verpoorte, Robert; Choi, Young Hae

    2013-11-22

    Mixtures of solid chemicals may become liquid under certain conditions. These liquids are characterized by the formation of strong ionic (ionic liquids) or hydrogen bonds (deep eutectic solvents). Due to their extremely low vapor pressure, they are now widely used in polymer chemistry and synthetic organic chemistry, yet little attention has been paid to their use as extraction solvents of natural products. This review summarizes the preparation of ionic liquids and deep eutectic solvents with natural product components and recent progress in their applications to the extraction and analysis of natural products as well as the recovery of extracted compounds from their extracts. Additionally, various factors affecting extraction features of ionic liquids and deep eutectic solvents, as well as potential useful technologies including microwave and ultrasound to increase the extraction efficiency, are discussed.

  15. 29 CFR 779.19 - Employer, employee, and employ.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... of oppressive child labor. The Act provides its own definitions of “employer,” “employee”, and... relation to an employee but shall not include the United States or any State or political subdivision of a State (except with respect to employees of a State or a political subdivision thereof, employed (a) in...

  16. 29 CFR 779.19 - Employer, employee, and employ.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... of oppressive child labor. The Act provides its own definitions of “employer,” “employee”, and... relation to an employee but shall not include the United States or any State or political subdivision of a State (except with respect to employees of a State or a political subdivision thereof, employed (a) in...

  17. 29 CFR 779.19 - Employer, employee, and employ.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... of oppressive child labor. The Act provides its own definitions of “employer,” “employee”, and... relation to an employee but shall not include the United States or any State or political subdivision of a State (except with respect to employees of a State or a political subdivision thereof, employed (a) in...

  18. Graduates', University Lecturers' and Employers' Perceptions towards Employability Skills

    ERIC Educational Resources Information Center

    Wickramasinghe, Vathsala; Perera, Lasantha

    2010-01-01

    Purpose: The purpose of this study is to explore employability skills that employers, university lecturers and graduates value to bring to the workplace, when graduates are applying for entry-level graduate jobs in the field of computer science in Sri Lanka. Design/methodology/approach: A total of three samples were selected for this exploratory…

  19. Conceptualizing Learning and Employability "Learning and Employability Framework"

    ERIC Educational Resources Information Center

    Sumanasiri, Erabaddage Gishan Tharanga; Yajid, Mohd Shukri Ab; Khatibi, Ali

    2015-01-01

    Extensive studies have been done on employability and the factors that lead to employability. Previous studies have focused on career development programs, internships, work experience programs, soft-skill development programs, and even university admission criteria which can be considered external factors to university student learning…

  20. Graduates' Employment and the Discourse of Employability: A Critical Analysis

    ERIC Educational Resources Information Center

    Moreau, Marie-Pierre; Leathwood, Carole

    2006-01-01

    In a context of considerable changes in the labour market and higher education sector in the UK, a discourse of employability has become increasingly dominant. Universities are urged to ensure that they produce "employable" graduates, and graduates themselves are exhorted to continually develop their personal skills, qualities and experiences in…

  1. 20 CFR 404.1003 - Employment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Employment. 404.1003 Section 404.1003...- ) Employment, Wages, Self-Employment, and Self-Employment Income Employment § 404.1003 Employment. Employment....1010. Section 404.1004 states the general rule on the kinds of work covered as employment....

  2. Breastfeeding and employment: an assessment of employer attitudes.

    PubMed

    Libbus, M Kay; Bullock, Linda F C

    2002-08-01

    Both research and anecdotal reports suggest that maternal employment is associated with failure to initiate breastfeeding and early breastfeeding attrition. The objective of this study was to describe the experience with and attitudes toward breastfeeding of a sample of employers in a small Midwestern city in the United States. Based on an analysis of 85 mail-out questionnaires, we found that less than half of the employers had personal experience with breastfeeding. A large percentage of the sample, however, indicated that they would be willing to facilitate women who wished to breastfeed or express milk in the workplace. However, these employers also stated that they saw little value to their business of supporting breastfeeding in the work environment. Thus, enhancement of breastfeeding opportunity in the work environment may come as a result of public and employer education but, more likely, will require some type of directive from official sources.

  3. Effect of solvent volume on the physical properties of aluminium doped nanocrystalline zinc oxide thin films deposited using a simplified spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Jabena Begum, N.; Mohan, R.; Ravichandran, K.

    2013-01-01

    Aluminium doped zinc oxide (AZO) thin films were deposited by employing a low cost and simplified spray technique using a perfume atomizer from starting solutions having different volumes (10, 20, … , 50 mL) of solvent. The effect of solvent volume on the structural, electrical, optical, photoluminescence (PL) and surface morphological properties was studied. The electrical resistivity of the AZO films is remarkably influenced by the variation in the solvent volume. The X-ray diffraction profiles clearly showed that all the films have preferential orientation along the (0 0 2) plane irrespective of the solvent volume. The crystallite size was found to be in the nano range of 35-46 nm. The optical transmittance in the visible region is desirably high (>85%). The AFM images show columnar morphology with varying grain size. The PL studies revealed that the AZO film deposited from 50 mL of solvent volume has good quality with lesser defect density.

  4. Development of solvent-free ambient mass spectrometry for green chemistry applications.

    PubMed

    Liu, Pengyuan; Forni, Amanda; Chen, Hao

    2014-04-15

    Green chemistry minimizes chemical process hazards in many ways, including eliminating traditional solvents or using alternative recyclable solvents such as ionic liquids. This concept is now adopted in this study for monitoring solvent-free reactions and analysis of ionic liquids, solids, and catalysts by mass spectrometry (MS), without using any solvent. In our approach, probe electrospray ionization (PESI), an ambient ionization method, was employed for this purpose. Neat viscous room-temperature ionic liquids (RTILs) in trace amounts (e.g., 25 nL) could be directly analyzed without sample carryover effect, thereby enabling high-throughput analysis. With the probe being heated, it can also ionize ionic solid compounds such as organometallic complexes as well as a variety of neat neutral solid chemicals (e.g., amines). More importantly, moisture-sensitive samples (e.g., [bmim][AlCl4]) can be successfully ionized. Furthermore, detection of organometallic catalysts (including air-sensitive [Rh-MeDuPHOS][OTf]) in ionic liquids, a traditionally challenging task due to strong ion suppression effect from ionic liquids, can be enabled using PESI. In addition, PESI can be an ideal approach for monitoring solvent-free reactions. Using PESI-MS, we successfully examined the alkylation of amines by alcohols, the conversion of pyrylium into pyridinium, and the condensation of aldehydes with indoles as well as air- and moisture-sensitive reactions such as the oxidation of ferrocene and the condensation of pyrazoles with borohydride. Interestingly, besides the expected reaction products, the reaction intermediates such as the monopyrazolylborate ion were also observed, providing insightful information for reaction mechanisms. We believe that the presented solvent-free PESI-MS method would impact the green chemistry field. PMID:24670064

  5. Synergistic Effects of Binary-Solvent Annealing for Efficient Polymer-Fullerene Bulk Heterojunction Solar Cells.

    PubMed

    Wu, Fu-Chiao; Li, Yi-Hao; Tsou, Chieh-Jen; Tung, Kuo-Cheng; Yen, Chia-Te; Chou, Fang-Sheng; Tang, Fu-Ching; Chou, Wei-Yang; Ruan, Jrjeng; Cheng, Horng-Long

    2015-09-01

    Conjugated polymer-fullerene-based bulk-heterojunction (BHJ) organic solar cells (OSCs) have attracted tremendous attention over the past two decades because of their potential to develop low-cost and easy methods to produce energy from light. The complicated microstructure and morphology with randomly organized architecture of these polymer-fullerene-based active layers (ALs) is a key factor that limits photovoltaic performance. In this study, a binary-solvent annealing (BSA) approach was established to improve the poly(3-hexylthiophene):indene-C60 bisadduct-based AL for efficient BHJ-type OSCs by varying the second solvents with different boiling points (BP). Thus, we were able to change the evaporation behavior of cosolvents and consequently obtain the various microstructural properties of the AL. An in-depth study was conducted on the solvent-evaporation driven morphology of the active layer under various cosolvent conditions and its effect on the photovoltaic parameters of OSCs. Under the BSA processes, we found that the specimens with low-BP second solvents allows us to observe a more ideal AL for increasing photon absorption and efficient charge transport and collection at the respective electrodes, resulting in enhanced PCE of the corresponding OSCs. By contrast, the specimens with high-BP second solvents exhibit random microstructures, which are detrimental to charge transport and collection and lead to diminished PCE of the corresponding OSCs. By appropriately selecting the composition of a binary solvent, BSA can be employed as an easy method for the effective manipulation of the microstructures of ALs. BSA is a promising technique for the performance enhancement of not only OSCs but also other organic/polymeric-based electronic devices. PMID:26267758

  6. Development of solvent-free ambient mass spectrometry for green chemistry applications.

    PubMed

    Liu, Pengyuan; Forni, Amanda; Chen, Hao

    2014-04-15

    Green chemistry minimizes chemical process hazards in many ways, including eliminating traditional solvents or using alternative recyclable solvents such as ionic liquids. This concept is now adopted in this study for monitoring solvent-free reactions and analysis of ionic liquids, solids, and catalysts by mass spectrometry (MS), without using any solvent. In our approach, probe electrospray ionization (PESI), an ambient ionization method, was employed for this purpose. Neat viscous room-temperature ionic liquids (RTILs) in trace amounts (e.g., 25 nL) could be directly analyzed without sample carryover effect, thereby enabling high-throughput analysis. With the probe being heated, it can also ionize ionic solid compounds such as organometallic complexes as well as a variety of neat neutral solid chemicals (e.g., amines). More importantly, moisture-sensitive samples (e.g., [bmim][AlCl4]) can be successfully ionized. Furthermore, detection of organometallic catalysts (including air-sensitive [Rh-MeDuPHOS][OTf]) in ionic liquids, a traditionally challenging task due to strong ion suppression effect from ionic liquids, can be enabled using PESI. In addition, PESI can be an ideal approach for monitoring solvent-free reactions. Using PESI-MS, we successfully examined the alkylation of amines by alcohols, the conversion of pyrylium into pyridinium, and the condensation of aldehydes with indoles as well as air- and moisture-sensitive reactions such as the oxidation of ferrocene and the condensation of pyrazoles with borohydride. Interestingly, besides the expected reaction products, the reaction intermediates such as the monopyrazolylborate ion were also observed, providing insightful information for reaction mechanisms. We believe that the presented solvent-free PESI-MS method would impact the green chemistry field.

  7. The Ideal Solvent for Paper Chromatography of Food Dyes.

    ERIC Educational Resources Information Center

    Markow, Peter G.

    1988-01-01

    Uses paper chromatography with food dyes to provide a simple and inexpensive basis for teaching chromatography. Provides experimental methodology and tabled results. Includes a solvent system comparison (Rf) for seven dyes and twenty-two solvents. (MVL)

  8. Safety in the Chemical Laboratory: Cyclohexane as a Cryoscopic Solvent.

    ERIC Educational Resources Information Center

    Steffel, Margaret J.

    1981-01-01

    Suggests that cyclohexane be used as a solvent in experiments usually using benzene, which has been placed on the list of chemicals that are confirmed carcinogens. Reasons for selection of cyclohexane and experimental procedures using this solvent are described. (CS)

  9. Organic Solvent Tropical Report [SEC 1 and 2

    SciTech Connect

    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.

  10. The effect of pressure, isotopic (H/D) substitution, and other variables on miscibility in polymer-solvent systems. The nature of the demixing process; dynamic light scattering and small angle neutron scattering studies. Final report

    SciTech Connect

    Van Hook, W.A.

    2000-01-01

    A research program examining the effects of pressure, isotope substitution and other variables on miscibility in polymer solvent systems is described. The techniques employed included phase equilibrium measurements and dynamic light scattering and small angle neutron scattering.

  11. Employer Evaluation of Occupational Programs.

    ERIC Educational Resources Information Center

    Willett, Lynn H.; Piland, William E.

    In an effort to meet the need for a more comprehensive program evaluation, staff at Moraine Valley Community College developed a questionnaire and interview schedule to obtain feedback from employers concerning career programs. Questionnaires were sent to all employers who hired graduates of occupational programs between 1969-71; over 80% returned…

  12. Employment Obtaining and Business Starting

    ERIC Educational Resources Information Center

    Lan, Jian

    2009-01-01

    The implementation of business starting education in higher vocational colleges is of important and realistic meanings for cultivating advanced technology application-type talents and for releasing the employment obtaining pressure of higher vocational students. Based on the analysis on the employment situation of higher vocational graduates, this…

  13. Employability Skills. At a Glance

    ERIC Educational Resources Information Center

    Wibrow, Bridget

    2011-01-01

    In a competitive workforce it is not just having the right qualification or technical skills that will land an individual a job; it could very well be their interpersonal skills. How someone communicates is often the first impression an employer has of a possible worker. Yet, it is precisely communication skills that employers feel applicants are…

  14. Employment and People with Disabilities.

    ERIC Educational Resources Information Center

    Nathanson, Jeanne H., Ed.

    1990-01-01

    This newsletter issue offers six articles on employment of people with disabilities. "Employment and People with Disabilities: Challenges for the Nineties" (Frank Bowe) discusses the Americans with Disabilities Act, issues in unemployment and under-education, earnings, and implications for the Office of Special Education and Rehabilitative…

  15. Employment Discrimination in Higher Education.

    ERIC Educational Resources Information Center

    Hustoles, Thomas P.; Griffin, Oren R.

    2000-01-01

    Reviews court decisions related to employment discrimination in higher education. The most significant development was a series of cases affirming that Eleventh Amendment immunity from private money damage claims brought pursuant to various federal employment discrimination statutes applied to state colleges and universities. (SLD)

  16. Special Issue on Casual Employment.

    ERIC Educational Resources Information Center

    Australian Bulletin of Labour, 2001

    2001-01-01

    Includes "Editor's Introduction" (Cully); "A New Estimate of Casual Employment?" (Campbell, Burgess); "A New Estimate of Casual Employment?: Reply" (Murtough, Waite); "The 'Long-term or Permanent Casual'--An Oxymoron or 'A Well Enough Understood Australianism' in the Law?" (Owens); and "The ACTU's [Australian Council of Trade Unions] Response to…

  17. Tracking Success in Youth Employment.

    ERIC Educational Resources Information Center

    Rieder, Corinne H.

    1979-01-01

    Youthwork, Incorporated, was created by the Youth Employment and Demonstration Projects Act of 1977 (YEDPA) to keep track of youth employment and training programs. Privately-owned Youthwork administers federal demonstration grants across the country to help provide job guidance, work experience credit, private sector involvement, and…

  18. MEETING TODAY'S CHALLENGE FOR EMPLOYMENT.

    ERIC Educational Resources Information Center

    HELER, EDWARD; MCNULTY, EMMETT T.

    POVERTY IS LINKED TO THE OPPORTUNITY FOR AND THE AVAILABILITY OF EMPLOYMENT. THE IMPOVERISHED LACK THE SKILLS, EDUCATION, FLEXIBILITY, AND MOBILITY REQUIRED FOR EMPLOYMENT. THIS IS ESPECIALLY TRUE OF ARIZONA'S MINORITY GROUPS--INDIANS, NEGROES, AND MEXICAN-AMERICANS. COMPETITION FOR JOBS NOT REQUIRING EXTENSIVE EDUCATION, AND THE FLOOD OF THE…

  19. Employment Outlook, Life Science Occupations.

    ERIC Educational Resources Information Center

    Bureau of Labor Statistics (DOL), Washington, DC.

    The nature of the work performed by biologists and biochemists is described in general terms, and for the subcategories such as agronomists, pharmacologists and entomologists. The types of employment opportunities, the necessary training the employment outlook and typical salaries and working conditions are described. Addresses for requesting…

  20. Employer Demands from Business Graduates

    ERIC Educational Resources Information Center

    McMurray, Stephen; Dutton, Matthew; McQuaid, Ronald; Richard, Alec

    2016-01-01

    Purpose: The purpose of this paper is to report on research carried out with employers to determine demand for business and management skills in the Scottish workforce. Design/methodology/approach: The research used a questionnaire in which employers were interviewed (either telephone or face to face), completed themselves and returned by e-mail,…

  1. Employability: Review and Research Prospects

    ERIC Educational Resources Information Center

    Guilbert, Laure; Bernaud, Jean-Luc; Gouvernet, Brice; Rossier, Jérôme

    2016-01-01

    Professional transition, employment, and reemployment are major concerns for nations facing adverse economic situations. The employability construct represents a scientific challenge in order to better understand the relationship between the job seekers' issues and the expectations of the world of work. This paper presents a review of the concept…

  2. Primer of Equal Employment Opportunity.

    ERIC Educational Resources Information Center

    Anderson, Howard J.

    This booklet presents laws and court cases concerning discrimination in hiring. It begins with a presentation of the laws and orders regulating equal employment opportunity and the remedies available. It lists those employees and employers to whom the laws apply and exemptions. Sections deal with discrimination on the basis of race, sex, sexual…

  3. Supported Employment. Missouri LINC Module.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Coll. of Education.

    This module provides information on supported employment as outlined in the Rehabilitation Act Amendments of 1986, P.L. 99-506. It discusses models of supported employment; the roles of vocational rehabilitation counselors, school district personnel, and job coaches; and what school district personnel can do to prepare students for supported…

  4. Employment Survey 1982. AIP Report.

    ERIC Educational Resources Information Center

    Ellis, Susanne D.

    The employment status of 1981-1982 degree recipients in physics and astronomy was surveyed. Information is presented on changes in occupational status of physics and astronomy degree recipients which occurred between the summer of 1982 and the following winter. The characteristics of graduates of both fields who were employed full-time or…

  5. Consumer Leadership in Supported Employment.

    ERIC Educational Resources Information Center

    Inge, Katherine J., Ed.

    1992-01-01

    This newsletter issue provides rehabilitation professionals with various information pieces concerning consumer leadership in supported employment of people with disabilities. First, a chart lists five questions concerning self advocacy and supported employment, and provides consumer responses to the questions. A second item describes…

  6. Preferential Remedies for Employment Discrimination

    ERIC Educational Resources Information Center

    Edwards, Harry T.; Zaretsky, Barry L.

    1975-01-01

    An overview of the problem of preferential remedies to achieve equal employment opportunities for women and minority groups. Contends that "color blindness" will not end discrimination but that some form of "color conscious" affirmative action program must be employed. Temporary preferential treatment is justified, according to the author, by the…

  7. Functionalization of graphene using deep eutectic solvents

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  8. Myoglobin solvent structure at different temperatures

    SciTech Connect

    Daniels, B.V.; Korszun, Z.R.; Schoenborn, B.P.

    1994-12-31

    The structure of the solvent surrounding myoglobin crystals has been analyzed using neutron diffraction data, and the results indicate that the water around the protein is not disordered, but rather lies in well-defined hydration shells. We have analyzed the structure of the solvent surrounding the protein by collecting neutron diffraction data at four different temperatures, namely, 80, 130, 180, and 240K. Relative Wilson Statistics applied to low resolution data showed evidence of a phase transition in the region of 180K. A plot of the liquidity factor, B{sub sn}, versus distance from the protein surface begins with a high plateau near the surface of the protein and drops to two minima at distances from the protein surface of about 2.35{Angstrom} and 3.85{Angstrom}. Two distinct hydration shells are observed. Both hydration shells are observed to expand as the temperature is increased.

  9. Structuring of polymer solutions upon solvent evaporation

    NASA Astrophysics Data System (ADS)

    Schaefer, C.; van der Schoot, P.; Michels, J. J.

    2015-02-01

    The morphology of solution-cast, phase-separated polymers becomes finer with increasing solvent evaporation rate. We address this observation theoretically for a model polymer where demixing is induced by steady solvent evaporation. In contrast to what is the case for a classical, thermal quench involving immiscible blends, the spinodal instability initially develops slowly and the associated length scale is not time invariant but decreases with time as t-1 /2. After a time lag, phase separation accelerates. Time lag and characteristic length exhibit power-law behavior as a function of the evaporation rate with exponents of -2 /3 and -1 /6 . Interestingly, at later stages the spinodal structure disappears completely while a second length scale develops. The associated structure coarsens but does not follow the usual Lifshitz-Slyozov-Wagner kinetics.

  10. Selective solvent absorption in coal conversion

    SciTech Connect

    Larsen, J.W.; Amui, J.

    1992-06-01

    The objectives of this research are: (1) to determine the importance of the presence of added hydrogen donor compounds within the coal in the first stage of direct liquefaction processes; and (2) to determine the composition of the solvent absorbed by and present within the coal in the first stages of direct coal liquefaction. Scope of work study the conversion of Argonne Premium coals in tetralin and 2-t-butyltetralin and compare the following: conversion to soluble products and product composition. Hydrogen donated by both solvents will be measured by gas chromatography and the same technique will be used to establish the amount of dealkylation of 2-t-butyltetralin. Reactions will be performed at several different temperatures for varying amounts of time.

  11. Indentation of polydimethylsiloxane submerged in organic solvents

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    This study 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 curve measured experimentally to that derived from the theory of poroelasticity, one can identify elastic constants and permeability. The measured elastic constants are interpreted within the Flory-Huggins theory. The measured permeabilities indicate that the solvents migrate in PDMS by diffusion, rather than by convection. This work confirms that indentation is a reliable and convenient method to characterize swollen elastomers.

  12. Development of a solvent processed insensitive propellant

    NASA Technical Reports Server (NTRS)

    Trask, R.; Costa, E.; Beardell, A. J.

    1980-01-01

    Two types of low vulnerability propellants are studied which are distinguished by whether the binder is a rubber, such as polyurethane or CTBN, or a plasticizable polymer such as ethyl cellulose or cellulose acetate. The former propellants are made by a partial cure extrusion process while the latter are made by the conventional solvent process. Emphasis is given to a cellulose binder (plasticizer) RDX composition. The type of binder used, the particle size of the RDX and the presence of small quantities of nitrocellulose in the solvent processed compositions have important influences on the mechanical and combustion characteristics of the propellant. The low temperature combustion is of particular concern because of potential breakup of the grains that can lead to instability.

  13. Gamma Ray Radiolysis of the FPEX Solvent

    SciTech Connect

    B. J. Mincher; S. P. Mezyk; D. R. Peterman

    2006-09-01

    Slide presentation. FPEX contains a calixarene for Cs extraction, a crown ether for Sr extraction, Cs7SB modifier, and TOA to aid in stripping, in Isopar L diluent. The radiation stability FPEX must be evaluated prior to process use. Radiolytic degradation of species in solution are due to reaction with the direct radiolysis products of the diluent. In Isopar L, the reactive species produced include e-, •H and alkane radicals, resulting in a reducing environment. However, in nitric acid, oxidizing hydroxyl (•OH) and nitro (•NO2) radicals dominate system chemistry. Thus, the nature of diluent and the presence of radical scavengers affect the results of irradiation. We report the preliminary results of a new program to investigate the radiolysis of FPEX using the 60Co irradiation of FPEX neat solvent, acid pre-equilibrated solvent and mixed aerated phases. The Cs and Sr distribution ratios were used as metrics.

  14. Production of biodiesel using expanded gas solvents

    SciTech Connect

    Ginosar, Daniel M; Fox, Robert V; Petkovic, Lucia M

    2009-04-07

    A method of producing an alkyl ester. The method comprises providing an alcohol and a triglyceride or fatty acid. An expanding gas is dissolved into the alcohol to form a gas expanded solvent. The alcohol is reacted with the triglyceride or fatty acid in a single phase to produce the alkyl ester. The expanding gas may be a nonpolar expanding gas, such as carbon dioxide, methane, ethane, propane, butane, pentane, ethylene, propylene, butylene, pentene, isomers thereof, and mixtures thereof, which is dissolved into the alcohol. The gas expanded solvent may be maintained at a temperature below, at, or above a critical temperature of the expanding gas and at a pressure below, at, or above a critical pressure of the expanding gas.

  15. Interfacial chemistry in solvent extraction systems

    SciTech Connect

    Neuman, R.D.

    1992-01-01

    Research last year emphasized the nature of microscopic interfaces, i. e., reversed micelles and other association microstructures, which form in both practical and simplified acidic organophosphorus extraction systems associated with Ni, Co and Na in order to improve on a recently proposed model for aggregation of metal-extractant complexes. Also, the macroscopic interfacial behavior of extractant molecules and their interactions with metal ions which occur in hydrometallurgical solvent extraction systems were further investigated.

  16. Coupling of protein dynamics with the solvent

    NASA Astrophysics Data System (ADS)

    Caliskan, Gokhan; Sauzan, Azzam; Mehtani, Disha; Sokolov, Alexei

    2003-03-01

    Glycerol and trehalose are among the many viscous solvents that are widely used for biostabilization and controlling the dynamics of proteins. It is believed that the suppression of the structural relaxations by high viscosity of solvent is responsible for improved stability in proteins. However, results of [1] and [2] demonstrate stronger suppression of biochemical activity and dynamics of proteins by liquid glycerol than by solid trehalose in a wide temperature range. The authors tried to explain the counterintuitive observations by a possible decoupling of the dynamics of the protein from trehalose. In order to test the validity of this assumption and to investigate the influence of the fast dynamics in proteins, the low frequency Raman scattering spectroscopy technique is used. Both relaxational and vibrational dynamics of glycerol, trehalose, and lysozyme in glycerol and in trehalose are studied in a wide temperature range. Dynamics of lysozyme in glycerol follows the strong temperature dependence of relaxational and vibrational dynamics of the bulk glycerol. On the other hand, the weak temperature dependence of dynamics of lysozyme in trehalose follows exactly the behavior of pure trehalose. This proves that there is a strong dynamic coupling between the protein and the solvents used. Interestingly, stronger relaxations in solid trehalose as compared to liquid glycerol are observed in the GHz region at low temperatures. This could be the reason for the enhanced protein activity observed in trehalose, compared to that in glycerol in this temperature range. Suppression of these fast relaxations should be the key for providing long-term stability to proteins. 1. Sastry, G.M. and N. Agmon, Trehalose prevents myoglobin collapse and preserves its internal mobility. BIOCHEMISTRY, 1997, 36(23): p. 7097-108. 2. Caliskan, G., et al., Influence of solvent on dynamics and stability of a protein. Journal of Non-Crystalline Solids, 2002, 307-310: p. 887-893.

  17. ALKYL PYROPHOSPHATE METAL SOLVENT EXTRACTANTS AND PROCESS

    DOEpatents

    Long, R.L.

    1958-09-30

    A process is presented for the recovery of uranium from aqueous mineral acidic solutions by solvent extraction. The extractant is a synmmetrical dialkyl pyrophosphate in which the alkyl substituents have a chain length of from 4 to 17 carbon atoms. Mentioned as a preferred extractant is dioctyl pyrophosphate. The uranium is precipitated irom the organic extractant phase with an agent such as HF, fluoride salts. alcohol, or ammonia.

  18. Solvent extraction of Southern US tar sands

    SciTech Connect

    Penney, W.R.

    1990-01-01

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

  19. 27 CFR 21.125 - Rubber hydrocarbon solvent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative....

  20. 27 CFR 21.125 - Rubber hydrocarbon solvent.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative....