超临界二氧化碳/聚乙二醇两相体系的性质及其在催化反应中的应用

Supercritical Carbon Dioxide/Poly(ethylene glycol) Biphasic System: Properties and Application to Catalysis

非均相催化过程中常常出现产物的转化率低、选择性差的问题,而均相催化过程往往具有优异的催化性能,但是却受制于催化剂、产物难于分离而达到循环使用的缺点.近年来两相催化体系的发展为这些问题的解决提供了一条新途径.超临界二氧化碳/聚乙二醇参与的两相体系是使用超临界二氧化碳作流动相,聚乙二醇作为另一溶剂之一,用于固定和稳定催化剂,进行有机催化反应.其显著特点是:可在反应的同时实现分离的操作,可实现均相催化过程的连续化.综述了超临界二氧化碳/聚乙二醇体系的相行为及其性质,并介绍了其在催化合成反应中的应用.

Homogeneous catalysts have many advantages, including high activity and selectivity, while they generally induce problems at the separation stage of a process, both in product purification and in catalyst recovery. Biphasic systems have provided a new approach to solve these problems. The biphasic catalysis systems using supercritical carbon dioxide （scCO2） as the continuous phase and poly（ethylene glycol） （PEG） as the stationary catalyst phase are described herein for the chemical reactions. This biphasic system has the especial advantage that combines reaction and separation into only one integrated process easily, in other words, reaction and separation can be completed simultaneously. Recent progress in this field is reviewed.