The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform
Stig E. Friberg - One of the best experts on this subject based on the ideXlab platform.
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Effect of relative humidity on the evaporation path from a Phenethyl Alcohol emulsion.
Journal of colloid and interface science, 2009Co-Authors: Stig E. FribergAbstract:Abstract The evaporation path for emulsions of Phenethyl Alcohol stabilized by a non-ionic surfactant, Laureth 4, a commercial ethoxy adduct, approximately C 12 (EO) 4 , was estimated by calculations using the phase diagram. The results for emulsions with an O/W ratio equal to or greater than 1/3 showed the relative humidity only in excess of 90% to have a significant effect on the evaporation path. In fact the path was not significantly modified for relative humidities from 0% to 90%, but in the range 90–100% the modification of the evaporation path was most pronounced; not only altering the path, but causing entirely different phases to appear in the emulsion. On the other hand, for emulsions with lower O/W ratios these effects were substantial for relative humidities down to the level of 40%.
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Vapor pressures of Phenethyl Alcohol in the system water-Phenethyl Alcohol and the triblock copolymer EO4.5PO59EO4.5
Journal of Dispersion Science and Technology, 2000Co-Authors: Stig E. Friberg, Jennifer L. Barber, Qi Yin, Patricia A AikensAbstract:ABSTRACT The phase diagram of water, Phenethyl Alcohol (PEA) and the triblock copolymer EO4.5PO59EO4.5, (EO = ethylene oxide, PO = propylene oxide), L101, was determined and the vapor pressures of PEA were measured for different phases. The phase diagram was almost identical to the corresponding one with a simple nonionic surfactant, Laureth 4, (≃C12EO4), but the PEA vapor pressure variation with mole fraction was significantly different reflecting the strong molecular interaction between PEA and the polymer. This distinction was mainly due to difference in molecular size; vapor pressure plots against weight fraction gave curves with only moderate variance. The results were used to discuss the variation in the PEA vapor pressure with time after application of a vesicular solution of PEA stabilized either by L101 or Laureth 4. The moderate differences in vapor pressures had a significant influence on the estimated curves of PEA pressure versus time.
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Phase behavior of a fragrance compound system: Water/Phenethyl Alcohol/laureth 4/glycerol
Journal of Surfactants and Detergents, 1999Co-Authors: Stig E. Friberg, Abeer Al-bawab, Joel D. Sandburg, Jennifer L. Barber, Qi Yin, Patricia A AikensAbstract:The phase diagram of the system water/Phenethyl Alcohol (PEA)/Laureth 4 (L4)/glycerol was determined using visual observation, optical microscopy, small-angle X-ray diffractometry, and the vapor pressure of Phenethyl Alcohol measured by gas chromatographic analysis of headspace vapor at equilibrium. The phase diagram was shown to be dominated by three narrow isotropic liquid solubility regions along the water/glycerol, glycerol/PEA, and PEA/L4 axes. Vapor pressure measurements and tie-line determinations showed the final state of formulations after evaporation of water to be emulsions of glycerol/PEA-in-L4/PEA or L4/PEA-in-glycerol/PEA. PEA was predominantly dissolved in the L4/PEA phase because the chemical potential of PEA in glycerol was high, even at modest concentrations.
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phase behavior of a fragrance compound system water Phenethyl Alcohol laureth 4 glycerol
Journal of Surfactants and Detergents, 1999Co-Authors: Stig E. Friberg, Joel D. Sandburg, Jennifer L. Barber, Qi Yin, Abeer Albawab, Patricia A AikensAbstract:The phase diagram of the system water/Phenethyl Alcohol (PEA)/Laureth 4 (L4)/glycerol was determined using visual observation, optical microscopy, small-angle X-ray diffractometry, and the vapor pressure of Phenethyl Alcohol measured by gas chromatographic analysis of headspace vapor at equilibrium. The phase diagram was shown to be dominated by three narrow isotropic liquid solubility regions along the water/glycerol, glycerol/PEA, and PEA/L4 axes. Vapor pressure measurements and tie-line determinations showed the final state of formulations after evaporation of water to be emulsions of glycerol/PEA-in-L4/PEA or L4/PEA-in-glycerol/PEA. PEA was predominantly dissolved in the L4/PEA phase because the chemical potential of PEA in glycerol was high, even at modest concentrations.
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Vapour pressures of Phenethyl Alcohol and limonene in systems with water and Laureth 4.
International journal of cosmetic science, 1998Co-Authors: Stig E. Friberg, Qi Yin, Patricia A AikensAbstract:Synopsis The vapour pressures of Phenethyl Alcohol and limonene in their water-in-oil microemulsion region were measured by head space gas chromatography of equilibrated samples. The results showed that the vapour pressure of both fragrance compounds in their mutual solutions without surfactant or water was significantly greater than that in ideal solutions. The high vapour pressure of Phenethyl Alcohol in such solutions was strongly reduced by addition of the surfactant, Laureth 4, a commercial nonionic surfactant, approximately teteraethylene glycol dodecyl ether. Saturation of the solutions with water gave a further reduction in the vapour pressure. The high vapour pressure of limonene was not influenced to a corresponding degree; in fact, only a small influence was found. The results were interpreted as resulting from differences in intermolecular interactions due to location of the fragrance compounds in different parts of the colloidal association structures. Resume On a mesure les tensions de vapeur de l'alcool phenetylique et du limonene dans leur zone de micro-emulsion eau-dans-huile par chromatographie gazeuse head space sur des echantillons equilibres. Les resultats montrent que la tension de vapeur des deux substances odorantes dans leurs solutions mutuelles sans tensioactif ni eau est significativement plus elevee que celle en solutions ideales. La tension de vapeur elevee de l'alcool phenetylique dans de telles solutions est fortement reduite par l'addition du tensioactif, le Laureth 4, tensioactif commercial non ionique; approximativement ether dodecylique de tetraethylene glycol. La saturation des solutions avec de l'eau provoque une reduction supplementaire de la tension de vapeur. La tension de vapeur elevee du limonene n'est pas affectee a un tel degre; en fait on ne constate qu'une petite influence. Les resultats sont interpretes comme venant de differences dans les interactions intermoleculaires dues a la localisation des substances odorantes dans differentes parties des structures d'association colloidales.
George B. Delancey - One of the best experts on this subject based on the ideXlab platform.
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A predictive thermodynamic model for the bioreduction of acetophenone to Phenethyl Alcohol using resting cells of Saccharomyces cerevisiae
Biotechnology and bioengineering, 1999Co-Authors: Yujun Zhao, George B. DelanceyAbstract:Equilibrium conversions were observed in the range of 60.2-76.0% with different initial compositions of reaction media for the bioreduction of acetophenone using resting cells of Saccharomyces cerevisiae in aqueous solutions at 30 degrees C. The reduction of acetophenone in the cells under anaerobic conditions is considered to be coupled with the oxidation of ethanol to acetate in the cytoplasm. A biphasic thermodynamic model is proposed which includes a nonuniform distribution of reagents across the cell membrane, a transmembrane pH gradient, ideal and nonideal solution models, and a basic reaction stoichiometry (ACP + (1/2) EtOH + (1/2)H2O PEA + (1/2)Ac- + (1/2)H+). The intracellular activity coefficients were based on the Lewis-Randall rule for acetophenone, Phenethyl Alcohol, and H2O and Henry's law for ethanol, acetate anion, and H+. The overall standard Gibbs free energy was estimated to be -0.11 kcal/mol at a pH 7, 25 degrees C, and 1 atm. The intracellular thermodynamic activity coefficients of acetophenone and Phenethyl Alcohol were predicted to be 471.2 and 866.4, respectively, using the measured initial distribution coefficients and calculated extracellular activity coefficients. The model reflected a zero Gibbs free energy change at calculated conversions within 4% of the measured equilibrium conversions. The analysis verified the effect of the concentration ratio of the substrate acetophenone to the co-substrate ethanol on the conversion efficiency and suggested that the intracellular pH and the pH gradient across the cell transmembrane significantly affect the predicted equilibrium conversion. The intracellular pH of resting, viable cells of Bakers' yeast at the bioconversion conditions was determined experimentally to be 5.77.
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Diffusion of acetophenone and Phenethyl Alcohol in the calcium-alginate–bakers' yeast–hexane system
Biotechnology and bioengineering, 1994Co-Authors: M. Sidhoum, George B. DelanceyAbstract:The intrabead diffusion coefficients of acetophenone and Phenethyl Alcohol were measured at 30 degrees C in the triphasic immobilized yeast-water-hexane system. Saccharomyces cerevisiae cells were deactivated with hydrochloric acid and entrapped in calcium-alginate beads. Measurements of dry cell loss during deactivation, shrinkage of the beads during deactivation and the final porosity of the beads were made for various cell loadings. Final concentrations of wet cells in the beads ranged from approximately 0.25 to 0.30 g/mL. Mass transfer in the hexane phase, external to the beads, was eliminated experimentally. The estimated error of 5% to 10% in the diffusion coefficients is within the experimental error associated with the bead method. The effect of significant sampling volumes on the diffusivities was estimated theoretically and accounted for experimentally. The intrabead concentration of acetophenone and Phenethyl Alcohol was 150 to 800 ppm. The deactivated cells were shown to be impervious to acetophenone so that the measured diffusivities are extracellular parameters. The cell volume fraction in the beads ranged from 0.70 to 0.90, significantly higher than previously reported data. The effective diffusion coefficients conform to the random pore model. No diffusional interaction between acetophenone and Phenethyl Alcohol was observed. The addition of 2 vol% ethanol or methanol slightly increased the diffusivities. The thermodynamic partition coefficients were measured in the bead-free water-organic system and found to be an order of magnitude lower than the values calculated from the analysis of the diffusion data for the organic-bead system, suggesting that bead-free equilibrium data cannot be used in triphasic systems. (c) 1994 John Wiley & Sons, Inc.
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diffusion of acetophenone and Phenethyl Alcohol in the calcium alginate bakers yeast hexane system
Biotechnology and Bioengineering, 1994Co-Authors: M. Sidhoum, George B. DelanceyAbstract:The intrabead diffusion coefficients of acetophenone and Phenethyl Alcohol were measured at 30 degrees C in the triphasic immobilized yeast-water-hexane system. Saccharomyces cerevisiae cells were deactivated with hydrochloric acid and entrapped in calcium-alginate beads. Measurements of dry cell loss during deactivation, shrinkage of the beads during deactivation and the final porosity of the beads were made for various cell loadings. Final concentrations of wet cells in the beads ranged from approximately 0.25 to 0.30 g/mL. Mass transfer in the hexane phase, external to the beads, was eliminated experimentally. The estimated error of 5% to 10% in the diffusion coefficients is within the experimental error associated with the bead method. The effect of significant sampling volumes on the diffusivities was estimated theoretically and accounted for experimentally. The intrabead concentration of acetophenone and Phenethyl Alcohol was 150 to 800 ppm. The deactivated cells were shown to be impervious to acetophenone so that the measured diffusivities are extracellular parameters. The cell volume fraction in the beads ranged from 0.70 to 0.90, significantly higher than previously reported data. The effective diffusion coefficients conform to the random pore model. No diffusional interaction between acetophenone and Phenethyl Alcohol was observed. The addition of 2 vol% ethanol or methanol slightly increased the diffusivities. The thermodynamic partition coefficients were measured in the bead-free water-organic system and found to be an order of magnitude lower than the values calculated from the analysis of the diffusion data for the organic-bead system, suggesting that bead-free equilibrium data cannot be used in triphasic systems. (c) 1994 John Wiley & Sons, Inc.
Kai Guo - One of the best experts on this subject based on the ideXlab platform.
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copper tempo catalyzed synthesis of α ketoamides via tandem sp3c h aerobic oxidation and amination of Phenethyl Alcohol derivatives
Organic and Biomolecular Chemistry, 2016Co-Authors: Chengkou Liu, Zhao Yang, Shiyu Guo, Yu Zeng, Ning Zhu, Zheng Fang, Kai GuoAbstract:An efficient copper–TEMPO-catalyzed one-pot synthesis of α-ketoamides from Phenethyl Alcohol derivatives was developed firstly. Moreover, molecular oxygen in open air was employed as the oxidant with a broad substrate scope, which makes this methodology more practical. Based on some control experiments, a plausible mechanism was proposed.
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Copper–TEMPO-catalyzed synthesis of α-ketoamides via tandem sp3C–H aerobic oxidation and amination of Phenethyl Alcohol derivatives
Organic & biomolecular chemistry, 2016Co-Authors: Chengkou Liu, Zhao Yang, Shiyu Guo, Yu Zeng, Ning Zhu, Zheng Fang, Kai GuoAbstract:An efficient copper–TEMPO-catalyzed one-pot synthesis of α-ketoamides from Phenethyl Alcohol derivatives was developed firstly. Moreover, molecular oxygen in open air was employed as the oxidant with a broad substrate scope, which makes this methodology more practical. Based on some control experiments, a plausible mechanism was proposed.
Raghunath V. Chaudhari - One of the best experts on this subject based on the ideXlab platform.
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Reaction kinetics of the selective liquid phase hydrogenation of styrene oxide to β-Phenethyl Alcohol
Journal of Molecular Catalysis A-chemical, 2003Co-Authors: Chandrashekhar V. Rode, M.m. Telkar, R. Jaganathan, Raghunath V. ChaudhariAbstract:Abstract Liquid phase hydrogenation of styrene oxide using 1% Pd/C and NaOH as a promoter was found to give selectively β-Phenethyl Alcohol (PEA) under very mild conditions (313–333 K; 0.68–5.5 MPa). The kinetics of this system was investigated by collecting initial rate data in a batch slurry reactor. Rate of hydrogenation was found to decrease beyond a certain concentration of both hydrogen (>3 MPa) and styrene oxide (>0.5 kmol/m 3 ). A Langmuir–Hinshelwood type rate equation has been proposed based on the initial rate data in the kinetic regime. The model predictions agree very well with the experimentally observed concentration–time data indicating the applicability of the proposed rate model.
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Alkali promoted regio-selective hydrogenation of styrene oxide to β-Phenethyl Alcohol
Studies in Surface Science and Catalysis, 2000Co-Authors: Chandrashekhar V. Rode, M.m. Telkar, Raghunath V. ChaudhariAbstract:The selective hydrogenation of styrene oxide to 2-phenyl ethanol (β-Phenethyl Alcohol) has been investigated using different catalysts and supports. The effect of reaction conditions such as H 2 pressure, agitation speed, concentration of substrate and temperature on the initial rate of reaction was investigated. The complete conversion of styrene oxide was obtained using 1% Pd/C, as a catalyst, under milder temperature (313K) and pressure (2.048 MPa) conditions. 2-phenyl ethanol was selectively formed when alkali was used as a promoter. A plausible mechanistic pathway has also been proposed for the hydrogenation of the styrene oxide to 2-phenyl ethanol.
Bing Yan - One of the best experts on this subject based on the ideXlab platform.
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A Postsynthetic Modified MOF Hybrid as Heterogeneous Photocatalyst for α-Phenethyl Alcohol and Reusable Fluorescence Sensor
Inorganic chemistry, 2016Co-Authors: Xiao Lian, Bing YanAbstract:The recent discovery of lanthanide-based metal–organic frameworks (Ln-MOFs) offers the potential to extend the chemical sensing and catalysis capabilities of metal–organic frameworks (MOFs). Herein, a new europium functionalized material based on MIL-125(Ti)-NH2 is synthesized by covalent postsynthetic modification and shows photocatalytic oxidation properties of α-Phenethyl Alcohol, and their fluorescence quenching behaviors are investigated. The catalytic efficiency is tested by monitoring the photocatalytic oxidation of α-Phenethyl Alcohol under ultraviolet light irradiation. Furthermore, MIL-125(Ti)-AM-Eu is developed as a fluorescence sensor integrated with its photocatalytic and luminescent properties. The MIL-125(Ti)-AM-Eu is used for detecting α-Phenethyl Alcohol, which could be successfully oxidized to acetophenone by the catalyst, and the fluorescence of MIL-125(Ti)-AM-Eu has changed accordingly.
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A Postsynthetic Modified MOF Hybrid as Heterogeneous Photocatalyst for α‑Phenethyl Alcohol and Reusable Fluorescence Sensor
2016Co-Authors: Xiao Lian, Bing YanAbstract:The recent discovery of lanthanide-based metal–organic frameworks (Ln-MOFs) offers the potential to extend the chemical sensing and catalysis capabilities of metal–organic frameworks (MOFs). Herein, a new europium functionalized material based on MIL-125(Ti)-NH2 is synthesized by covalent postsynthetic modification and shows photocatalytic oxidation properties of α-Phenethyl Alcohol, and their fluorescence quenching behaviors are investigated. The catalytic efficiency is tested by monitoring the photocatalytic oxidation of α-Phenethyl Alcohol under ultraviolet light irradiation. Furthermore, MIL-125(Ti)-AM-Eu is developed as a fluorescence sensor integrated with its photocatalytic and luminescent properties. The MIL-125(Ti)-AM-Eu is used for detecting α-Phenethyl Alcohol, which could be successfully oxidized to acetophenone by the catalyst, and the fluorescence of MIL-125(Ti)-AM-Eu has changed accordingly