申请人:——
公开号:US20040015005A1
公开(公告)日:2004-01-22
The present invention provides a method for preparing ester or thioester that can conduct catalytic esterification reaction with an equimolar amount of carboxylic acid and alcohol, or catalytic thioesterification reaction with carboxylic acid and an equimolar amount or small amount of thiol, and can be expected as an industrial method that needs an enormous amount of synthesis in the light of green chemistry. By using hafnium chloride (IV), especially tetravalent hafnium compounds represented by hafnium chloride (IV)•(THF)
2
or hafnium (IV)t-butoxide as a (poly) condensation catalyst, direct condensation reaction is conducted from carboxylic acid and an equimolar amount of alcohol or a little smaller amount of thiol, in the nonpolar solvent such as toluene and the like, in a deoxidization atmosphere and under heating reflux, and the reaction synthesizes ester monomer or thioester monomer, polyester or polythioester. When heating reflux is conducted by using a nonpolar solvent, it is preferable to remove azeotropic water from the reaction system.
本发明提供了一种制备酯或硫酯的方法,该方法可以与等摩尔量的羧酸和醇进行催化酯化反应,或者与羧酸和等摩尔量或少量硫醇进行催化硫酯化反应,可望作为一种需要大量合成的工业方法,符合绿色化学的原则。通过使用四氯化铪(IV),特别是以四氯化铪(IV)•(THF)2或四氯化铪(IV)t-丁氧基表示的四价铪化合物作为(聚)缩聚催化剂,可以从羧酸和等摩尔量的醇或稍微较少量的硫醇,在非极性溶剂如甲苯等中,在脱氧环境和加热回流下进行直接缩聚反应,合成酯单体或硫酯单体,聚酯或聚硫酯。当使用非极性溶剂进行加热回流时,最好从反应系统中去除共沸水。