The Experts below are selected from a list of 504 Experts worldwide ranked by ideXlab platform
Tomokazu Yoshimura - One of the best experts on this subject based on the ideXlab platform.
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adsorption and aggregation properties of homogeneous polyoxypropylene polyoxyethylene alkyl Ether type nonionic surfactants
Langmuir, 2017Co-Authors: Shiho Yada, Satoru Hashimoto, Toshiyuki Suzuki, Tomokazu YoshimuraAbstract:Homogeneous polyoxypropylene (PO)–polyoxyethylene (EO) alkyl Ether type nonionic surfactants comprising alkyl, EO, and PO chains with identical chain length distributions (CnEOxPOy; alkyl chain length n = 10, 12, 14, or 16; EO chain length x = 4, 6, or 8; and PO chain length y = 1, 2, or 3) were synthesized from homogeneous polyoxyethylene alkyl Ether bromide and monosodium polyoxypropylene by Williamson Ether Synthesis. The adsorption and aggregation properties of these surfactants were characterized (cloud point, surface tension, dynamic light scattering, small-angle X-ray scattering, polarization microscopy, and cryogenic transmission electron microscopy) and compared to those of conventional homogeneous EO alkyl Ether type nonionic surfactants (CnEOx). The introduction of a PO chain to the EO terminal group of the CnEOx species lowered the cloud points, especially for x = 6. Contrary to our expectations, the CnEOxPOy surfactants adsorbed efficiently at the air/water interface, despite their complex st...
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Adsorption and Aggregation Properties of Homogeneous Polyoxypropylene–Polyoxyethylene Alkyl Ether Type Nonionic Surfactants
Langmuir, 2017Co-Authors: Shiho Yada, Satoru Hashimoto, Toshiyuki Suzuki, Tomokazu YoshimuraAbstract:Homogeneous polyoxypropylene (PO)–polyoxyethylene (EO) alkyl Ether type nonionic surfactants comprising alkyl, EO, and PO chains with identical chain length distributions (CnEOxPOy; alkyl chain length n = 10, 12, 14, or 16; EO chain length x = 4, 6, or 8; and PO chain length y = 1, 2, or 3) were synthesized from homogeneous polyoxyethylene alkyl Ether bromide and monosodium polyoxypropylene by Williamson Ether Synthesis. The adsorption and aggregation properties of these surfactants were characterized (cloud point, surface tension, dynamic light scattering, small-angle X-ray scattering, polarization microscopy, and cryogenic transmission electron microscopy) and compared to those of conventional homogeneous EO alkyl Ether type nonionic surfactants (CnEOx). The introduction of a PO chain to the EO terminal group of the CnEOx species lowered the cloud points, especially for x = 6. Contrary to our expectations, the CnEOxPOy surfactants adsorbed efficiently at the air/water interface, despite their complex st...
Marsha R Baar - One of the best experts on this subject based on the ideXlab platform.
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Microwave-Enhanced Organic Syntheses for the Undergraduate Laboratory: Diels−Alder Cycloaddition, Wittig Reaction, and Williamson Ether Synthesis
Journal of Chemical Education, 2020Co-Authors: Marsha R Baar, Danielle Falcone, Christopher M GordonAbstract:Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels−Alder cycloaddition, a Wittig salt formation, and a Williamson Ether Synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig salt and Ether preparations. The Diels-Alder cycloaddition of N-phenylmaleimide and 1,3-cyclohexadiene in absolute ethanol in a closed vessel and 130 °C gave 84−90% yields. Formation of the Wittig salt, benzyltriphenylphosphonium chloride, from triphenylphosphine and benzyl chloride gave yields greater than 90% when heated in acetonitrile at 200 °C Yields doubled in the Williamson Ether Synthesis of 2-ethoxynaphthalene, from 2-naphthol, methanolic potassium hydroxide, and iodoethane with microwave heating at 130 °C.
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research experience for the organic chemistry laboratory a student centered optimization of a microwave enhanced Williamson Ether Synthesis and gc analysis
Journal of Chemical Education, 2018Co-Authors: Marsha R BaarAbstract:An inquiry-based experiment for the organic chemistry laboratory was developed to provide students with a cognitively rich research experience. Student teams were charged with optimizing the reaction conditions for the Williamson Ether Synthesis of 2-fluorophenetole from 2-fluorophenol, ethyl bromide, and potassium carbonate in either absolute ethanol or acetonitrile. Microwave acceleration of this SN2 reaction followed by rapid GC–MS analysis allowed students to review results, revise experimental conditions, and repeat the modified reaction and its analysis within a 3 h laboratory period. Variables that could be manipulated were reagent equivalencies, solvents and their volume, microwave reaction time, temperature, and wattage. Post-laboratory, all team data were available to the entire class for additional evaluation and each student was required to suggest new conditions for improvement in his/her laboratory report.
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pedagogical comparison of five reactions performed under microwave heating in multi mode versus mono mode ovens diels alder cycloaddition wittig salt formation e2 dehydrohalogenation to form an alkyne Williamson Ether Synthesis and fischer esterifica
Journal of Chemical Education, 2014Co-Authors: Marsha R Baar, William Gammerdinger, Jennifer Leap, Erin Morales, Jonathan Shikora, Michael H WeberAbstract:Five reactions were rate-accelerated relative to the standard reflux workup in both multi-mode and mono-mode microwave ovens, and the results were compared to determine whEther the sequential processing of a mono-mode unit could provide for better lab logistics and pedagogy. Conditions were optimized so that yields matched in both types of microwave ovens for a Diels–Alder cycloaddition, Wittig salt formation, Fischer esterifications, an E2 alkyne formation, and Williamson Ether Synthesis. Typically, a 10-fold rate acceleration was observed under mono-mode heating versus multi-mode heating, reducing the total run-time between 1.5 and 3.0 min per sample, which rivals the batch run-time of a multi-mode unit in ∼16 student lab sections. Thus, the mono-mode microwave oven required a similar quantity of total reaction time in the lab, allowing students to run their experiments individually with less wait-time, competition for chemicals, equipment, and instrumentation and to complete the experiments in the lab ...
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Pedagogical Comparison of Five Reactions Performed under Microwave Heating in Multi-Mode versus Mono-Mode Ovens: Diels–Alder Cycloaddition, Wittig Salt Formation, E2 Dehydrohalogenation To Form an Alkyne, Williamson Ether Synthesis, and Fischer Ester
Journal of Chemical Education, 2014Co-Authors: Marsha R Baar, William Gammerdinger, Jennifer Leap, Erin Morales, Jonathan Shikora, Michael H WeberAbstract:Five reactions were rate-accelerated relative to the standard reflux workup in both multi-mode and mono-mode microwave ovens, and the results were compared to determine whEther the sequential processing of a mono-mode unit could provide for better lab logistics and pedagogy. Conditions were optimized so that yields matched in both types of microwave ovens for a Diels–Alder cycloaddition, Wittig salt formation, Fischer esterifications, an E2 alkyne formation, and Williamson Ether Synthesis. Typically, a 10-fold rate acceleration was observed under mono-mode heating versus multi-mode heating, reducing the total run-time between 1.5 and 3.0 min per sample, which rivals the batch run-time of a multi-mode unit in ∼16 student lab sections. Thus, the mono-mode microwave oven required a similar quantity of total reaction time in the lab, allowing students to run their experiments individually with less wait-time, competition for chemicals, equipment, and instrumentation and to complete the experiments in the lab ...
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microwave enhanced organic syntheses for the undergraduate laboratory diels alder cycloaddition wittig reaction and Williamson Ether Synthesis
Journal of Chemical Education, 2010Co-Authors: Marsha R Baar, Danielle Falcone, Christopher M GordonAbstract:Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels−Alder cycloaddition, a Wittig salt formation, and a Williamson Ether Synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig salt and Ether preparations. The Diels-Alder cycloaddition of N-phenylmaleimide and 1,3-cyclohexadiene in absolute ethanol in a closed vessel and 130 °C gave 84−90% yields. Formation of the Wittig salt, benzyltriphenylphosphonium chloride, from triphenylphosphine and benzyl chloride gave yields greater than 90% when heated in acetonitrile at 200 °C Yields doubled in the Williamson Ether Synthesis of 2-ethoxynaphthalene, from 2-naphthol, methanolic potassium hydroxide, and iodoethane with microwave heating at 130 °C.
Shiho Yada - One of the best experts on this subject based on the ideXlab platform.
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adsorption and aggregation properties of homogeneous polyoxypropylene polyoxyethylene alkyl Ether type nonionic surfactants
Langmuir, 2017Co-Authors: Shiho Yada, Satoru Hashimoto, Toshiyuki Suzuki, Tomokazu YoshimuraAbstract:Homogeneous polyoxypropylene (PO)–polyoxyethylene (EO) alkyl Ether type nonionic surfactants comprising alkyl, EO, and PO chains with identical chain length distributions (CnEOxPOy; alkyl chain length n = 10, 12, 14, or 16; EO chain length x = 4, 6, or 8; and PO chain length y = 1, 2, or 3) were synthesized from homogeneous polyoxyethylene alkyl Ether bromide and monosodium polyoxypropylene by Williamson Ether Synthesis. The adsorption and aggregation properties of these surfactants were characterized (cloud point, surface tension, dynamic light scattering, small-angle X-ray scattering, polarization microscopy, and cryogenic transmission electron microscopy) and compared to those of conventional homogeneous EO alkyl Ether type nonionic surfactants (CnEOx). The introduction of a PO chain to the EO terminal group of the CnEOx species lowered the cloud points, especially for x = 6. Contrary to our expectations, the CnEOxPOy surfactants adsorbed efficiently at the air/water interface, despite their complex st...
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Adsorption and Aggregation Properties of Homogeneous Polyoxypropylene–Polyoxyethylene Alkyl Ether Type Nonionic Surfactants
Langmuir, 2017Co-Authors: Shiho Yada, Satoru Hashimoto, Toshiyuki Suzuki, Tomokazu YoshimuraAbstract:Homogeneous polyoxypropylene (PO)–polyoxyethylene (EO) alkyl Ether type nonionic surfactants comprising alkyl, EO, and PO chains with identical chain length distributions (CnEOxPOy; alkyl chain length n = 10, 12, 14, or 16; EO chain length x = 4, 6, or 8; and PO chain length y = 1, 2, or 3) were synthesized from homogeneous polyoxyethylene alkyl Ether bromide and monosodium polyoxypropylene by Williamson Ether Synthesis. The adsorption and aggregation properties of these surfactants were characterized (cloud point, surface tension, dynamic light scattering, small-angle X-ray scattering, polarization microscopy, and cryogenic transmission electron microscopy) and compared to those of conventional homogeneous EO alkyl Ether type nonionic surfactants (CnEOx). The introduction of a PO chain to the EO terminal group of the CnEOx species lowered the cloud points, especially for x = 6. Contrary to our expectations, the CnEOxPOy surfactants adsorbed efficiently at the air/water interface, despite their complex st...
Seiji Iwasa - One of the best experts on this subject based on the ideXlab platform.
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Williamson Ether Synthesis with phenols at a tertiary stereogenic carbon formal enantioselective phenoxylation of β keto esters
Chemistry: A European Journal, 2015Co-Authors: Kazutaka Shibatomi, Manato Kotozaki, Nozomi Sasaki, Ikuhide Fujisawa, Seiji IwasaAbstract:The enantioselective formation of α-aryloxy-β-keto esters is described for the first time. Lewis acid catalyzed enantioselective chlorination of β-keto esters and subsequent SN 2 reactions with phenols yielded α-aryloxy-β-keto esters with up to 96% ee. Favorskii rearrangement of α-chloro-β-keto esters was also found to give 1,2-diesters with slightly reduced enantiopurity.
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Williamson Ether Synthesis with Phenols at a Tertiary Stereogenic Carbon: Formal Enantioselective Phenoxylation of β‐Keto Esters
Chemistry: A European Journal, 2015Co-Authors: Kazutaka Shibatomi, Manato Kotozaki, Nozomi Sasaki, Ikuhide Fujisawa, Seiji IwasaAbstract:The enantioselective formation of α-aryloxy-β-keto esters is described for the first time. Lewis acid catalyzed enantioselective chlorination of β-keto esters and subsequent SN 2 reactions with phenols yielded α-aryloxy-β-keto esters with up to 96% ee. Favorskii rearrangement of α-chloro-β-keto esters was also found to give 1,2-diesters with slightly reduced enantiopurity.
Bernard Boutevin - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of glycerin carbonate-based intermediates using thiol–ene chemistry and isocyanate free polyhydroxyurethanes therefrom
Polymer Chemistry, 2011Co-Authors: Sofia Benyahya, Stéphane Carlotti, Myriam Desroches, Remi Auvergne, Sylvain Caillol, Bernard BoutevinAbstract:A new Synthesis of 4-[(prop-2-en-1-yloxy)methyl]-1,3-dioxolan-2-one (AGC) was performed by Williamson Ether Synthesis from 4-(hydroxymethyl)-1,3-dioxolan-2-one. Dicyclocarbonates were synthesized by UV thiol–ene coupling of allyl-cyclocarbonate with a 2,2′-oxydiethanethiol. This photochemical thiol–ene reaction was carried out under air, with neither solvent nor photoinitiator. The products, obtained with high yield, were characterized by 1H NMR and FTIR analysis. The synthesized dicyclocarbonates were used without purification to synthesize polyhydroxyurethanes without isocyanate by step growth polyaddition with 1,10-diaminodecane. The synthesized polyhydroxyurethanes were characterized by 1H NMR, FTIR, ATG and DSC analysis. These polyhydroxyurethanes exhibited glass transition temperatures from −31 °C to −14 °C, molecular weight from 7,000 g mol−1 to 9000 g mol−1 and degradation temperature for 5% of weight loss (Td 5%) between 227 °C and 250 °C.
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Synthesis of glycerin carbonate-based intermediates using thiol–ene chemistry and isocyanate free polyhydroxyurethanes therefrom
Polymer Chemistry, 2011Co-Authors: Sofia Benyahya, Stéphane Carlotti, Myriam Desroches, Remi Auvergne, Sylvain Caillol, Bernard BoutevinAbstract:A new Synthesis of 4-[(prop-2-en-1-yloxy)methyl]-1,3-dioxolan-2-one (AGC) was performed by Williamson Ether Synthesis from 4-(hydroxymethyl)-1,3-dioxolan-2-one. Dicyclocarbonates were synthesized by UV thiol-ene coupling of allyl-cyclocarbonate with a 2,2[prime or minute]-oxydiethanethiol. This photochemical thiol-ene reaction was carried out under air, with neither solvent nor photoinitiator. The products, obtained with high yield, were characterized by 1H NMR and FTIR analysis. The synthesized dicyclocarbonates were used without purification to synthesize polyhydroxyurethanes without isocyanate by step growth polyaddition with 1,10-diaminodecane. The synthesized polyhydroxyurethanes were characterized by 1H NMR, FTIR, ATG and DSC analysis. These polyhydroxyurethanes exhibited glass transition temperatures from -31 [degree]C to -14 [degree]C, molecular weight from 7,000 g mol-1 to 9000 g mol-1 and degradation temperature for 5% of weight loss (Td 5%) between 227 [degree]C and 250 [degree]C.
