功能化离子液体在聚酯PET降解与合成中的应用

Degradation and Synthesis of Poly(Ethylene Terephthalate) by Functionalized Ionic Liquids

离子液体作为一类新兴的绿色环保型溶剂和催化剂,具有性质可调、溶解性好、催化活性高、热力学稳定性好和易于回收等优点而备受人们关注。聚酯具有多种优良性能,产能巨大,适用范围广,但造成的白色污染和资源浪费问题带来了严重的负面社会效应。通过化学回收方法,聚酯可降解为单体或低聚物从而被循环利用。本文概述了国内外废聚酯常用化学降解方法,包括水解法、甲醇降解法、乙醇降解法、乙二醇降解法等,并对主要化学降解方法的优缺点进行了比较。重点介绍了近年来功能化离子液体催化剂在聚对苯二甲酸乙二醇酯(PET)降解过程中的应用以及Lewis酸性离子液体催化乙二醇醇解PET机理,同时也描述了离子液体在聚酯合成环节中的应用。最后,总结了近年来国内外PET产能及消费量,探讨了离子液体催化剂在催化聚酯降解与合成中面临的诸多挑战。

As a green environmentally friendly solvent and catalyst,ionic liquids have attracted much attention because of their various properties,such as good solubility,high catalytic activity,good thermal stability and easy recycling. Polyesters have tremendous production capacity around the world with applications in wide ranges,and at the same time their wastes result in some negative effects on environment. This paper is aimed to reviewcommonly chemical degradation and recycling methods of polyester waste,and also the development in synthesis of polyester catalyzed by ionic liquids. Polyester can be easily converted into its monomers or oligomers by the method of chemical recycling for the purpose of recycling use. Several methods of chemical degradation of polyester waste locally and abroad are summarized,including hydrolysis method,methanol depolymerization method,ethanol depolymerization method,and ethylene glycol depolymerization method. The advantages and disadvantages of main chemical depolymerization methods are compared. Recent studies especially focus on degradation recycling of the most common polyester-poly（ethylene terephthalate）（PET）,using functionalized ionic liquids as catalyst. Other applications of functionalized ionic liquids catalyst in polymerization of PET and mechanism of the glycolysis of PET catalyzed by Lewis acidic ionic liquids are also introduced. At last,challenges in the synthesis and degradation of polyester catalyzed by Lewis acidic ionic liquids are overviewed.