【摘要】 研究了不同类型的酸催化剂对碳酸二甲酯与苯酚酯交换合成碳酸二苯酯的影响.实验结果表明,碳酸二甲酯与苯酚的酯交换反应是软碱(酚氧)亲硬酸(羰基碳)的反应;硬Lewis酸比软Lewis酸、交界Lewis酸和Brnsted酸有更高的酯交换选择性.将不同的磺基引入n-Bu2SnO分子中,制得一系列硬Lewis酸催化剂[n-Bu2Sn(OH)OS(O)2R(H2O)]2[R=p-NH2C6H4(Ⅰ),p-CH3C6H4(Ⅱ),C6H5(Ⅲ),p-ClC6H4(Ⅳ),Me(Ⅴ),CF3(Ⅵ)].在酯交换反应中,由于磺基的强吸电子效应增强了[n-Bu2Sn(OH)OS(O)2R(H2O)]2中Sn的Lewis酸性,其催化活性比n-Bu2SnO的高,而且磺基上取代基的吸电子效应越强,催化剂中Sn的Lewis酸性越强,催化活性越高,但取代基的吸电子效应过强会降低其对酯交换反应的选择性.更多还原

【Abstract】 Effect of different types of acid catalysts on the transesterification of dimethyl carbonate with phenol to diphenyl carbonate was investigated.The results show that the transesterification is the reaction of soft base(phenoxy)binding to hard acid(the carbonyl carbon in dimethyl carbonate),and hard Lewis acids exhibit higher transesterification selectivity than soft Lewis acids,border Lewis acids and Brnsted acids.When n-Bu2SnO was modified by different sulfonic acids,a series of hard Lewis acid catalysts [n-Bu2Sn(OH)OS\5(O)2R(H2O)]2 [R=p-NH2C6H4(Ⅰ),p-CH3C6H4(Ⅱ),C6H5(Ⅲ),p-ClC6H4(Ⅳ),Me(Ⅴ),CF3(Ⅵ)] were prepared.When they were used as the transesterification catalysts,their catalytic activities were higher than that of n-Bu2SnO because of the strong electron-withdrawing effect of sulfonic groups.And the stronger the electron-withdrawing effect of the substituent on the sulfonic group was,the greater the Lewis acidity of Sn in [n-Bu2Sn(OH)OS(O)2R(H2O)]2 was,the higher the catalytic activity was,but the excess electron-withdrawing effect of the substituent could decrease its transesterification selectivity.更多还原