乙酰丙酮锌高效催化废弃PET醇解机理  

Glycolysis mechanism of efficient catalyzing waste polyethylene terephthalate by zinc acetylacetonate

作　　者：曹静静 范楚梦 张蕾 江伟 曾桂香 孙平[1] 周天鹏 林予恒 李爱民[1] 张全兴[1] Jingjing Cao;Chumeng Fan;Lei Zhang;Wei Jiang;Guixiang Zeng;Ping Sun;Tianpeng Zhou;Yuheng Lin;Aimin Li;Quanxing Zhang(State Key Laboratory of Pollution Control and Resources Reuse,National Engineering Research Center for Organic Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210023,China;Kuang Yarning College and Institute of Brain Science,Nanjing University,Nanjing 210023,China;Institute of Theoretical and Computational Chemistry,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学环境学院,污染控制与资源化研究国家重点实验室,国家有机毒物污染控制与资源化工程技术研究中心,南京210023 [2]南京大学匡亚明学院和脑科学研究所,南京210023 [3]南京大学化学化工学院,理论和计算化学研究所,南京210023

出　　处：《中国科学：化学》2021年第12期1637-1645,共9页SCIENTIA SINICA Chimica

基　　金：国家重点研发计划(编号:YFC20181901404)资助项目。

摘　　要：聚对苯二甲酸乙二醇酯(PET)乙二醇醇解是把PET解聚为对苯二甲酸双羟乙酯(BHET)单体的高效方法,对解决废弃PET回收资源化问题具有重要意义.本研究针对传统醇解PET催化反应温度高、反应时间长、单体产率低等问题,开发了乙酰丙酮锌催化废弃PET高效解聚为BHET单体的方法.与已报道金属盐和离子液体催化剂相比,乙酰丙酮锌催化性能优异.在较温和的反应条件下(反应温度为175℃,反应时间为30 min,常压),PET的降解率达到100%以及BHET单体的产率可达88.1%.动力学研究结果表明PET催化降解反应符合收缩动力学反应模型.红外光谱和密度泛函理论计算表明,Zn(acac);与液相(EG)之间首先发生配体交换产生活性物种Zn(acac)(OCH;-CH;OH).随后PET的醇解反应通过Zn;和去质子化乙二醇配体的协同反应机制进行.Glycolysis of polyethylene terephthalate (PET) is an important method to depolymerize PET into bis(hydroxyethyl terephthalate)(BHET),which is of great significance to deal with the problem of recycling waste PET.In order to solve the problems of high temperature,long reaction time and low monomer yield in traditional glycolysis of PET,a new method of efficient depolymerization of waste PET to BHET monomer catalyzed by zinc acetylacetonate was developed.Experimentally,the reaction occurs quickly (30 min) under mild conditions (175℃ and atmospheric pressure) with excellent performance (degradation rate of 100% and BHET monomer yield of 88.1%) as compared with the metal salts and ionic liquids catalyzed reactions.Kinetic studies showed that the catalytic degradation of PET by Zn(acac);is in accordance with the shrinking-core model.Infrared spectrum and DFT calculations demonstrated that the active species of the catalytic reaction is Zn(acac)(OCH;CH;OH),which was produced through the ligand exchange between Zn(acac);and EG.Glycolysis of PET mediated by Zn(acac)(OCH;CH;OH) takes place through the cooperative functions of Zn;and deprotonated ethylene glycol ligand.

关 键 词：乙酰丙酮锌 废弃PET 协同催化 BHET 

分 类 号：X705[环境科学与工程—环境工程] TQ426[化学工程] TQ323.4