A series of zwitterionic‐type quaternary ammoniums(ZTQAs)with varying lengths of alkyl chains combined with KI were synthesized and considered as catalysts for the coupling reaction of CO2 and various terminal epoxid...A series of zwitterionic‐type quaternary ammoniums(ZTQAs)with varying lengths of alkyl chains combined with KI were synthesized and considered as catalysts for the coupling reaction of CO2 and various terminal epoxides.The prolonged alkyl chain of ZTQAs exhibited temperature‐responsive self‐separation in propylene carbonate(PC).The interaction between ZTQAs and KI was confirmed by X‐ray photoelectron spectroscopy and quantum chemical calculations.This interaction strengthened the nucleophilicity of the I?ion,favoring the catalytic reaction.The 3‐(dimethyltetradecylammonium)propane sulfonate(DTPS)/KI showed an excellent yield of PC(95.1%)at 125°C,1.5 MPa,and 1 mol%loading of catalyst.The precipitate formed spontaneously from the catalytic system,providing high catalytic activity of the homogeneous catalyst,as well as easy recovery of the heterogeneous catalyst.展开更多
A facile route for the synthesis of dimethyl adipate （DAP） from cyclopentanone and dimethyl carbonate （DMC） in the pres- ence of solid base catalysts has been developed. It was found that the intermediate carbomet...A facile route for the synthesis of dimethyl adipate （DAP） from cyclopentanone and dimethyl carbonate （DMC） in the pres- ence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclopentanone （CMCP） was produced from cyclopentanone with DMC in the first step, and then CMCP was further converted to DAP by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclopentanone via the abstraction of a proton in the a-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DAP.展开更多
基金supported by the National Natural Science Foundation of China(41330317,21403051)the Natural Science Foundation of Hebei province(B2016402030,B2017402079)+2 种基金the Science and Technology Foundation of Universities of Hebei Province(ZD2015113)the Science and Technology Research Development Program of Handan(1621211041-3,1622201049-2)the Program for One Hundred Innovative Talents in Universities of Hebei Province(BR2-204)~~
文摘A series of zwitterionic‐type quaternary ammoniums(ZTQAs)with varying lengths of alkyl chains combined with KI were synthesized and considered as catalysts for the coupling reaction of CO2 and various terminal epoxides.The prolonged alkyl chain of ZTQAs exhibited temperature‐responsive self‐separation in propylene carbonate(PC).The interaction between ZTQAs and KI was confirmed by X‐ray photoelectron spectroscopy and quantum chemical calculations.This interaction strengthened the nucleophilicity of the I?ion,favoring the catalytic reaction.The 3‐(dimethyltetradecylammonium)propane sulfonate(DTPS)/KI showed an excellent yield of PC(95.1%)at 125°C,1.5 MPa,and 1 mol%loading of catalyst.The precipitate formed spontaneously from the catalytic system,providing high catalytic activity of the homogeneous catalyst,as well as easy recovery of the heterogeneous catalyst.
基金supported by the Zhangjiang Science and Technology Development Foundation of Guangdong,China (2009C3101015)Doctoral Starting Foundation of Guangdong Medical College (XB0811)
文摘A facile route for the synthesis of dimethyl adipate （DAP） from cyclopentanone and dimethyl carbonate （DMC） in the pres- ence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclopentanone （CMCP） was produced from cyclopentanone with DMC in the first step, and then CMCP was further converted to DAP by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclopentanone via the abstraction of a proton in the a-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DAP.
