Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic...Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled proc-ess using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite mem-branes is given and possible future research is outlined.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Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled proc-ess using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite mem-branes is given and possible future research is outlined.
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.
