The Experts below are selected from a list of 108063 Experts worldwide ranked by ideXlab platform
Lidia Mabel Yudi - One of the best experts on this subject based on the ideXlab platform.
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Cation adsorption at a distearoylphosphatidic acid layer adsorbed at a liquid/liquid Interface
Electrochimica Acta, 2007Co-Authors: Lorena M. A. Monzon, Lidia Mabel YudiAbstract:The interfacial behaviour of tetraethylammonium cations (TEA+) at a liquid–liquid Interface modified with an anionic phospholipid layer, distearoyl phosphatidic acid (DSPA), is analysed, with the purpose of characterising the permeation properties of the film. The TEA+ concentration in aqueous solution and the amount of DSPA solution employed to generate the lipidic layer, were varied. The results indicate that the layer is tightly compact and the transfer of TEA+ cations by permeation does not take place. Instead of this, TEA+ ions adsorb at the polar head groups of DSPA, and these adsorbed cations could be acting as nucleation centres of DSPA molecules when the DSPA amount is low.
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ohmic drop effects in square wave voltammetry response for an ion transfer process at a liquid liquid Interface
Journal of Electroanalytical Chemistry, 2005Co-Authors: A V Juarez, Ana M. Baruzzi, Lidia Mabel YudiAbstract:Abstract The effect of ohmic drop on square-wave voltammetry experiments (SWV) at a liquid–liquid Interface is analyzed. The study is based on the distortion of SW voltammetric profiles of the tetraethyl ammonium transfer process across the water/1,2-dichloroethane Interface when an uncompensated resistance, R Ω , is present. Depending on the experimental conditions significant R Ω values arise as a consequence of the low electrical conductivity of the organic solvent characteristic of these systems, and efficient IR compensation is needed. When R Ω is not totally removed, a non-linear dependence of peak current (Δ I p ) on the square root of the frequency, an increase of half-peak width (Δ E p/2 ) and a shift of peak potential ( E p ) towards more positive values are observed in the SW profiles. The influence of signal frequency and R Ω values on SWV parameters (Δ I p , E p and Δ E p/2 ) is evaluated.
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Ohmic drop effects in square-wave voltammetry response for an ion transfer process at a liquid–liquid Interface
Journal of Electroanalytical Chemistry, 2005Co-Authors: A V Juarez, Ana M. Baruzzi, Lidia Mabel YudiAbstract:Abstract The effect of ohmic drop on square-wave voltammetry experiments (SWV) at a liquid–liquid Interface is analyzed. The study is based on the distortion of SW voltammetric profiles of the tetraethyl ammonium transfer process across the water/1,2-dichloroethane Interface when an uncompensated resistance, R Ω , is present. Depending on the experimental conditions significant R Ω values arise as a consequence of the low electrical conductivity of the organic solvent characteristic of these systems, and efficient IR compensation is needed. When R Ω is not totally removed, a non-linear dependence of peak current (Δ I p ) on the square root of the frequency, an increase of half-peak width (Δ E p/2 ) and a shift of peak potential ( E p ) towards more positive values are observed in the SW profiles. The influence of signal frequency and R Ω values on SWV parameters (Δ I p , E p and Δ E p/2 ) is evaluated.
Richard G Compton - One of the best experts on this subject based on the ideXlab platform.
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insights into the role of the liquid liquid Interface in biphasic reactions the reaction of vitamin b12s aq with vicinal dibromides oil
ChemPhysChem, 2005Co-Authors: Trevor J Davies, Christopher A Garner, Stephen G Davies, Richard G ComptonAbstract:Electrocatalytic processes can take place either homogeneously in a single liquid phase or heterogeneously at the Liquid-Liquid Interface formed in emulsions. This Article addresses the question as to whether a change in rate and/or mechanism can occur between the two possibilities. Specifically, cyclic voltammetry and electrosynthetic experiments are used to demonstrate that for the vitamin B12 mediated reduction of vicinal dibromides producing olefins, electric field effects likely operate at the Liquid-Liquid Interface which can change the populations of different conformers relative to the single homogeneous-phase experiment, leading to significant changes in rate.
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cyclic voltammetry at microdroplet modified electrodes a comparison of the reaction of vicinal dibromides with vitamin b12s at the liquid liquid Interface with the corresponding homogeneous process evidence for polar solvent effects at the liquid liq
Journal of Electroanalytical Chemistry, 2004Co-Authors: Trevor J Davies, Christopher A Garner, Stephen G Davies, Richard G ComptonAbstract:Abstract The electrocatalytic reactions of vitamin B12s with three vicinal dibromides (cis-1,2-dibromocyclohexane, trans-1,2-dibromocyclohexane and 1,2-dibromobutane) are investigated in homogeneous and heterogeneous media. In the latter, cyclic voltammetry with basal plane pyrolytic graphite electrodes modified with microdroplets of dodecane + dibromide is employed to obtain kinetic parameters for the liquid/liquid reaction. The homogeneous and interfacial reactions exhibit marked differences in reactivity and the contrasting behaviour of the two systems suggests the liquid/liquid Interface has a major role in the B12s/RBr2 reaction, consistent with a polar solvent effect.
Shinichi Ohashi - One of the best experts on this subject based on the ideXlab platform.
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synthesis of β caryophyllene oxide via regio and stereoselective endocyclic epoxidation of β caryophyllene with nemania aenea sf 10099 1 in a liquid liquid Interface bioreactor l l ibr
Journal of Bioscience and Bioengineering, 2011Co-Authors: Kanako Fujinuma, Akihito Inoue, Shinichi OhashiAbstract:Abstract Nemania aenea SF 10099-1, a basidiomycete isolated from a forest soil sample, regio- and stereoselectively epoxidized β-caryophyllene (Car) to (−)-β-caryophyllene oxide (Car-Ox) in a liquid–liquid Interface bioreactor (L–L IBR) consisted of a liquid medium (a bottom phase), a fungus-ballooned microsphere (MS) mat (a middle phase), and an organic phase containing Car (a top phase). The cultivation conditions, such as carbon and nitrogen sources, kind of MS, initial medium pH and Car concentration, were optimized in the L–L IBR system. The best carbon and nitrogen sources were xylose and tryptone, respectively. The most suitable polyacrylonitrile MS was MMF-DE-1 (former MFL-80SDE; non-coated type). Although the strain could not grow below pH 5.5, the endocyclic epoxidation of Car efficiently proceeded at a wide range of initial medium pH (6.0 to 9.0). The bioconversion system exhibited an excellent alleviation effect toward substrate and product inhibitions. While Car could be added into an organic phase (KF-96L-1CS, dimethyl silicone oil) at 50% (w/v), the accumulation of Car-Ox reached over 30 g/l in spite of these strong microbial toxicities. Moreover, the epoxidation reaction smoothly proceeded in a novel L–L IBR system, a multistory L–L IBR systems, consisted of 5 stacked reactor units. The optical rotation of Car-Ox produced was (−) and the enantiomeric excesses of (−)-β-Car-Ox purified by 1st and 2nd recrystallization from methanol reached 97.51 and 99.33%, respectively.
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Synthesis of (−)-β-caryophyllene oxide via regio- and stereoselective endocyclic epoxidation of β-caryophyllene with Nemania aenea SF 10099-1 in a liquid–liquid Interface bioreactor (L–L IBR)
Journal of Bioscience and Bioengineering, 2011Co-Authors: Kanako Fujinuma, Akihito Inoue, Shinichi OhashiAbstract:Abstract Nemania aenea SF 10099-1, a basidiomycete isolated from a forest soil sample, regio- and stereoselectively epoxidized β-caryophyllene (Car) to (−)-β-caryophyllene oxide (Car-Ox) in a liquid–liquid Interface bioreactor (L–L IBR) consisted of a liquid medium (a bottom phase), a fungus-ballooned microsphere (MS) mat (a middle phase), and an organic phase containing Car (a top phase). The cultivation conditions, such as carbon and nitrogen sources, kind of MS, initial medium pH and Car concentration, were optimized in the L–L IBR system. The best carbon and nitrogen sources were xylose and tryptone, respectively. The most suitable polyacrylonitrile MS was MMF-DE-1 (former MFL-80SDE; non-coated type). Although the strain could not grow below pH 5.5, the endocyclic epoxidation of Car efficiently proceeded at a wide range of initial medium pH (6.0 to 9.0). The bioconversion system exhibited an excellent alleviation effect toward substrate and product inhibitions. While Car could be added into an organic phase (KF-96L-1CS, dimethyl silicone oil) at 50% (w/v), the accumulation of Car-Ox reached over 30 g/l in spite of these strong microbial toxicities. Moreover, the epoxidation reaction smoothly proceeded in a novel L–L IBR system, a multistory L–L IBR systems, consisted of 5 stacked reactor units. The optical rotation of Car-Ox produced was (−) and the enantiomeric excesses of (−)-β-Car-Ox purified by 1st and 2nd recrystallization from methanol reached 97.51 and 99.33%, respectively.
A V Juarez - One of the best experts on this subject based on the ideXlab platform.
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ohmic drop effects in square wave voltammetry response for an ion transfer process at a liquid liquid Interface
Journal of Electroanalytical Chemistry, 2005Co-Authors: A V Juarez, Ana M. Baruzzi, Lidia Mabel YudiAbstract:Abstract The effect of ohmic drop on square-wave voltammetry experiments (SWV) at a liquid–liquid Interface is analyzed. The study is based on the distortion of SW voltammetric profiles of the tetraethyl ammonium transfer process across the water/1,2-dichloroethane Interface when an uncompensated resistance, R Ω , is present. Depending on the experimental conditions significant R Ω values arise as a consequence of the low electrical conductivity of the organic solvent characteristic of these systems, and efficient IR compensation is needed. When R Ω is not totally removed, a non-linear dependence of peak current (Δ I p ) on the square root of the frequency, an increase of half-peak width (Δ E p/2 ) and a shift of peak potential ( E p ) towards more positive values are observed in the SW profiles. The influence of signal frequency and R Ω values on SWV parameters (Δ I p , E p and Δ E p/2 ) is evaluated.
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Ohmic drop effects in square-wave voltammetry response for an ion transfer process at a liquid–liquid Interface
Journal of Electroanalytical Chemistry, 2005Co-Authors: A V Juarez, Ana M. Baruzzi, Lidia Mabel YudiAbstract:Abstract The effect of ohmic drop on square-wave voltammetry experiments (SWV) at a liquid–liquid Interface is analyzed. The study is based on the distortion of SW voltammetric profiles of the tetraethyl ammonium transfer process across the water/1,2-dichloroethane Interface when an uncompensated resistance, R Ω , is present. Depending on the experimental conditions significant R Ω values arise as a consequence of the low electrical conductivity of the organic solvent characteristic of these systems, and efficient IR compensation is needed. When R Ω is not totally removed, a non-linear dependence of peak current (Δ I p ) on the square root of the frequency, an increase of half-peak width (Δ E p/2 ) and a shift of peak potential ( E p ) towards more positive values are observed in the SW profiles. The influence of signal frequency and R Ω values on SWV parameters (Δ I p , E p and Δ E p/2 ) is evaluated.
Trevor J Davies - One of the best experts on this subject based on the ideXlab platform.
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insights into the role of the liquid liquid Interface in biphasic reactions the reaction of vitamin b12s aq with vicinal dibromides oil
ChemPhysChem, 2005Co-Authors: Trevor J Davies, Christopher A Garner, Stephen G Davies, Richard G ComptonAbstract:Electrocatalytic processes can take place either homogeneously in a single liquid phase or heterogeneously at the Liquid-Liquid Interface formed in emulsions. This Article addresses the question as to whether a change in rate and/or mechanism can occur between the two possibilities. Specifically, cyclic voltammetry and electrosynthetic experiments are used to demonstrate that for the vitamin B12 mediated reduction of vicinal dibromides producing olefins, electric field effects likely operate at the Liquid-Liquid Interface which can change the populations of different conformers relative to the single homogeneous-phase experiment, leading to significant changes in rate.
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cyclic voltammetry at microdroplet modified electrodes a comparison of the reaction of vicinal dibromides with vitamin b12s at the liquid liquid Interface with the corresponding homogeneous process evidence for polar solvent effects at the liquid liq
Journal of Electroanalytical Chemistry, 2004Co-Authors: Trevor J Davies, Christopher A Garner, Stephen G Davies, Richard G ComptonAbstract:Abstract The electrocatalytic reactions of vitamin B12s with three vicinal dibromides (cis-1,2-dibromocyclohexane, trans-1,2-dibromocyclohexane and 1,2-dibromobutane) are investigated in homogeneous and heterogeneous media. In the latter, cyclic voltammetry with basal plane pyrolytic graphite electrodes modified with microdroplets of dodecane + dibromide is employed to obtain kinetic parameters for the liquid/liquid reaction. The homogeneous and interfacial reactions exhibit marked differences in reactivity and the contrasting behaviour of the two systems suggests the liquid/liquid Interface has a major role in the B12s/RBr2 reaction, consistent with a polar solvent effect.