催化学报 ›› 2026, Vol. 86: 125-136.DOI: 10.1016/S1872-2067(26)65048-6

• 论文 • 上一篇    下一篇

溶剂工程与微波辐射协同促进高结晶度PET低温催化解聚

敖志锋,1, 何文轩,1, 滕志学, 刘熊唯, 沈志刚*()   

  1. 湘潭大学化工学院, 含碳废资源催化转化与再利用创新团队, 湖南湘潭 411105
  • 收稿日期:2025-11-01 接受日期:2026-01-13 出版日期:2026-07-05 发布日期:2026-06-12
  • 通讯作者: *电子信箱: zhigang_shen@xtu.edu.cn (沈志刚).
  • 作者简介:第一联系人:1共同第一作者.
  • 基金资助:
    国家重点研发项目(2022YFB3805400);国家自然科学基金(22178297);国家自然科学基金(22478327);湖南省科技创新计划(2024RC9009)

Synergistic solvent engineering and microwave radiation for efficient low-temperature catalytic depolymerization of high-crystallinity PET

Zhifeng Ao,1, Wenxuan He,1, Zhixue Teng, Xiongwei Liu, Zhigang Shen*()   

  1. College of Chemical Engineering, Xiangtan University, Xiangtan 411105, Hunan, China
  • Received:2025-11-01 Accepted:2026-01-13 Online:2026-07-05 Published:2026-06-12
  • About author:First author contact:1Contributed equally to this work.
  • Supported by:
    National Key Research and Development Program of China(2022YFB3805400);National Natural Science Foundation of China(22178297);National Natural Science Foundation of China(22478327);science and technology innovation Program of Hunan Province(2024RC9009)

摘要:

聚对苯二甲酸乙二醇酯(PET)作为全球产量最大的工程塑料之一, 其废弃物的大量累积已造成严重的资源浪费和环境负担. 通过乙二醇(EG)醇解法将PET解聚成单体对苯二甲酸双羟乙酯(BHET), 被认为是实现塑料循环经济的理想途径. 然而, PET化学惰性强且在EG中溶解性极低, 尤其是高结晶度PET(> 30%)中紧密堆积的晶区结构显著限制了反应物渗透与传质过程, 导致传统醇解工艺通常需在高温(> 190 ºC)条件下进行, 存在能耗高、效率低等问题. 因此, 开发适用于高结晶度PET在温和条件下高效解聚的新策略, 对于推动塑料循环经济发展具有重要意义.

本文提出了一种基于π-π相互作用导向的溶剂工程与微波辐射协同强化的PET解聚新策略, 以突破高结晶度PET(结晶度43.6%)低温解聚过程中的动力学瓶颈. 首先, 基于Hansen溶解度参数和密度泛函理论(DFT)计算, 从理论上筛选出具有强给电子特性的芳香族助溶剂(如N,N-二甲基苯胺). 实验与表征结果表明, 该类助溶剂具有双重功能: (1)通过“溶胀-刻蚀”效应显著改善PET溶解性, 使反应路径从受限的固液界面反应转变为高效的拟均相反应; (2)通过与PET分子链之间形成强π-π堆积作用, 促进电子向PET羰基氧转移, 从而调控酯键电子结构并增强Lewis酸催化剂对底物的活化能力. 为进一步降低反应能垒, 引入微波辐射技术, 利用反应溶剂EG的高介电损耗特性与微流控法合成的双功能ZnO催化剂(同时作为微波吸收剂和底物活化剂)的协同介电响应, 实现反应体系的快速、均匀加热. 动力学研究表明, 该溶剂-微波协同体系将PET解聚反应表观活化能从无助溶剂/常规加热体系的185 kJ·mol-1大幅降至45 kJ·mol-1. 在150 ºC的温和条件下, 仅需20 min即可实现PET转化率100%和BHET收率97.5%, 效率较对照组提升142倍. 此外, 该体系在5次循环实验中保持了优异的稳定性, 且对离子液体、金属盐、金属氧化物等多类催化剂均表现出良好的普适强化效果, 并能从含聚乙烯、聚丙烯、聚苯乙烯及纺织品的混合废弃物中高选择性地解聚回收PET.

综上, 本文不仅阐明了芳香族助溶剂与微波场协同强化聚合物解聚的内在机制, 还构建了一种面向高结晶度废PET高效回收的低能耗、高选择性、可持续技术平台, 为难降解塑料废弃物的资源化利用提供了新的理论基础与技术路径, 对推动废塑料循环经济与高值化利用具有重要意义.

关键词: PET乙二醇解, 过程强化, 助溶剂, 微波辐射, 选择性解聚

Abstract:

Conventional thermocatalytic recycling of plastics is typically constrained by high energy input requirements, leading to marginal gains in energy efficiency and yield. We herein report an innovative strategy that combines π-π interaction-guided solvent engineering with microwave irradiation to achieve rapid glycolysis of highly crystalline waste poly(ethylene terephthalate) (PET) under mild conditions. In spite of the lack of solubility of PET, the depolymerization pathway is shifted from a solid-liquid interfacial process to a pseudo-houmogeneous reaction through judicious cosolvent selection. Furthermore, π-π interactions between the cosolvent and PET modulate the electron density and nucleophilic character of the ester bonds, facilitating their activation by Lewis acid catalysts. Complementarily, microwave irradiation enables rapid and uniform heating via the synergistic dielectric response of ethylene glycol (high dielectric loss tangent) and a bifunctional ZnO catalyst (serving as both microwave absorber and substrate catalyst). The synergistic cosolvent-microwave system lowers the apparent activation energy for PET glycolysis from 185 to 45 kJ·mol-1, attaining 100% PET conversion and 97.5% bis(2-hydroxyethyl) terephthalate (BHET) yield at 150 °C within 20 min. This represents a 142-fold enhancement over the system devoid of cosolvent and microwave assistance. The integrated approach also exhibits excellent cycling stability, broad applicability across various catalysts, and selective PET depolymerization from mixed plastics, highlighting its potential as a sustainable platform for plastic waste valorization.

Key words: PET glycolysis, Process intensification, Cosolvent, Microwave irradiation, Selective depolymerization