开环聚合催化剂用于脂肪族聚酯合成的研究进展

Research Progress on Ring-opening Polymerization Catalysts and the Synthesis of Aliphatic Polyesters

与广泛使用的聚烯烃材料相比,脂肪族聚酯由于其独特的生物相容性和可降解性,在电子、包装和生物医学等领域都有广泛的应用.开环聚合(ROP)是目前合成脂肪族聚酯的主要方法,本文针对催化开环聚合用于合成脂肪族聚酯,总结了该领域所涉及的2类主要催化体系,即金属基催化剂和无金属有机催化剂,同时对新兴的酶催化体系做了初步介绍.列举了相关重要催化体系的化学结构,旨在揭示各类体系的催化反应特点,重点关注和评述了催化剂结构对催化效率、可控性、分子量和立体选择性的影响.金属基催化剂主要包括中心金属与N-杂环卡宾、硫脲等配位生成的配合物,其在结构上具有较大的可调性,可根据催化的需要选择不同的结构;而无金属有机催化剂如有机碱催化剂(如磷腈碱和N-杂环卡宾等),有机酸催化剂(如磷酸和方酸等),往往具有高效催化效率、摩尔质量控制和立体选择性的优点;除此以外脂肪酶催化剂具有反应范围广、反应温和以及无金属污染残留的特点.

Compared with widely used polyolefin materials,aliphatic polyesters can show the same properties,and their unique biocompatibility and degradability make them widely used in electronics,absorbable surgical suture,food packaging,biomedicine and so on.They have become an environmentally friendly substitute for traditional polyolefin plastics,especially aliphatic polyester materials derived from biomass.Ring opening polymerization(ROP)is the main method for synthesizing aliphatic polyester at present.Aiming at the application of catalytic ring opening polymerization in the synthesis of aliphatic polyester,this paper summarizes two main catalytic systems involved in this field,namely metal based catalyst and metal free organic catalyst,and gives a preliminary introduction to the emerging enzyme catalytic system.This paper lists the chemical structures of relevant important catalytic systems,aims to reveal the catalytic reaction characteristics of various systems,and focuses on and comments on the effects of catalyst structure on catalytic efficiency,controllability,molecular weight and stereoselectivity.Specifically,metal based catalysts mainly include complexes formed by the coordination of central metal with N-heterocyclic carbene and thiourea,which have great adjustability in structure,and different structures can be selected according to the needs of catalysis;Metal free organic catalysts such as organic base catalysts(phosphonitrile base,N-heterocyclic carbene,etc.)and organic acid catalysts(phosphoric acid,squaric acid,etc.)often have the advantages of high catalytic efficiency,molar mass control and stereoselectivity.In addition,lipase catalyst has the characteristics of wide reaction range,mild reaction and no metal pollution residue.