The benzene alkylation process for the production of ethylbenzene has undergone significant improvements during recent decades.Various environmentally benign zeolite-catalyzed ethylbenzene processes,including ZSM-5-ze...The benzene alkylation process for the production of ethylbenzene has undergone significant improvements during recent decades.Various environmentally benign zeolite-catalyzed ethylbenzene processes,including ZSM-5-zeolite-based vapor-phase ethylbenzene processes and Y-,β-,and MCM-22-zeolite-based liquid-phase processes,have been developed and commercialized.Pure ethylene,ethanol,and dilute ethylene have been used as ethylation agents.Here,the development and industrial application of alkylation catalysts and benzene ethylation techniques are summarized,and some other promising innovations are discussed.Recent advances in benzene alkylation over hierarchical zeolites with improved access to active sites and molecular transport are also covered.Zeolites with short diffusion lengths are promising candidates as better alkylation catalysts.The key point is how to obtain such materials easily and economically.The structure-activity relationships of commercial zeolites in these processes are discussed.Liquid-phase processes catalyzed by β and MCM-22 are more profitable than vapor-phase processes catalyzed by ZSM-5.展开更多
Methyl 3-hydroxypropanoate was synthesized via hydroesterification of ethylene oxide with CO in the presence of dicobalt octacarbonyl catalyst and methanol solvent. The catalyst exhibited high catalytic activity. The ...Methyl 3-hydroxypropanoate was synthesized via hydroesterification of ethylene oxide with CO in the presence of dicobalt octacarbonyl catalyst and methanol solvent. The catalyst exhibited high catalytic activity. The effect of reaction temperature, CO pressure, methanol dosage, catalyst dosage and reaction time on catalytic reaction was investigated. The test results revealed that this reaction was greatly affected by reaction temperature, but it was not significantly affected by the CO pressure, the methanol dosage, the catalyst dosage and the reaction time. Under the optimal conditions, the conversion of ethylene oxide was equal to 92.24%, while the selectivity and yield of methyl 3-hydroxypropanoate reached 88.99% and 84.35%, respectively.展开更多
Highly efficient asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed with （R）-oxynitrilase from defatted Prunus Japonica seed meal for the prep...Highly efficient asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed with （R）-oxynitrilase from defatted Prunus Japonica seed meal for the preparation of optically active （R）-2-trimethylsilyl-2-hydroxyl-propionitrile was successfully carried out for the first time. For better understanding of the reaction, various influential variables were examined with respect to the initial reaction rate, the substrate conversion and the product enantiomeric excess （e.e.）. Diisopropyl ether was found to be the best organic phase for this reaction among all the organic solvents tested. The optimal concentrations of Prunus Japonica seed meal powder, acetyltrimethylsilane and acetone cyanohydrin, volume ratio of aqueous phase to organic phase, buffer pH value and the reaction temperature were 34.5g·L^-1 and 14mmol· L^-1, 28mmol· L^-1, 13% （by volume）, 5.0 and 30℃, respectively, while the initial reaction rate, the substrate conversion and the product enantiomeric excess were 1.34 mmol·L^-1·h^-1, 99.0% and 99.0%, respectively. The comparative study demonstrated that silicon atom in substrate showed great effect on the reaction and acetyltrimethylsilane was a much better substrate for （R）-hydroxynitrile lyase from Prunus Japonica seed than its carbon analogue 3,3-dimethyl-2-butanone.展开更多
文摘The benzene alkylation process for the production of ethylbenzene has undergone significant improvements during recent decades.Various environmentally benign zeolite-catalyzed ethylbenzene processes,including ZSM-5-zeolite-based vapor-phase ethylbenzene processes and Y-,β-,and MCM-22-zeolite-based liquid-phase processes,have been developed and commercialized.Pure ethylene,ethanol,and dilute ethylene have been used as ethylation agents.Here,the development and industrial application of alkylation catalysts and benzene ethylation techniques are summarized,and some other promising innovations are discussed.Recent advances in benzene alkylation over hierarchical zeolites with improved access to active sites and molecular transport are also covered.Zeolites with short diffusion lengths are promising candidates as better alkylation catalysts.The key point is how to obtain such materials easily and economically.The structure-activity relationships of commercial zeolites in these processes are discussed.Liquid-phase processes catalyzed by β and MCM-22 are more profitable than vapor-phase processes catalyzed by ZSM-5.
基金supported by the Guangdong Province Natural Science Foundation (No. 10152500002000019)the Maoming City Science and Technology Planning Project (NO.2008024)
文摘Methyl 3-hydroxypropanoate was synthesized via hydroesterification of ethylene oxide with CO in the presence of dicobalt octacarbonyl catalyst and methanol solvent. The catalyst exhibited high catalytic activity. The effect of reaction temperature, CO pressure, methanol dosage, catalyst dosage and reaction time on catalytic reaction was investigated. The test results revealed that this reaction was greatly affected by reaction temperature, but it was not significantly affected by the CO pressure, the methanol dosage, the catalyst dosage and the reaction time. Under the optimal conditions, the conversion of ethylene oxide was equal to 92.24%, while the selectivity and yield of methyl 3-hydroxypropanoate reached 88.99% and 84.35%, respectively.
文摘Highly efficient asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed with （R）-oxynitrilase from defatted Prunus Japonica seed meal for the preparation of optically active （R）-2-trimethylsilyl-2-hydroxyl-propionitrile was successfully carried out for the first time. For better understanding of the reaction, various influential variables were examined with respect to the initial reaction rate, the substrate conversion and the product enantiomeric excess （e.e.）. Diisopropyl ether was found to be the best organic phase for this reaction among all the organic solvents tested. The optimal concentrations of Prunus Japonica seed meal powder, acetyltrimethylsilane and acetone cyanohydrin, volume ratio of aqueous phase to organic phase, buffer pH value and the reaction temperature were 34.5g·L^-1 and 14mmol· L^-1, 28mmol· L^-1, 13% （by volume）, 5.0 and 30℃, respectively, while the initial reaction rate, the substrate conversion and the product enantiomeric excess were 1.34 mmol·L^-1·h^-1, 99.0% and 99.0%, respectively. The comparative study demonstrated that silicon atom in substrate showed great effect on the reaction and acetyltrimethylsilane was a much better substrate for （R）-hydroxynitrile lyase from Prunus Japonica seed than its carbon analogue 3,3-dimethyl-2-butanone.
