吉林大学张越涛团队报道了镁基路易斯酸催化剂对聚酯和聚碳酸酯的无溶剂化学回收。相关研究成果于2024年12月24日发表于国际顶尖学术期刊《德国应用化学》。

开发一种简单有效的催化剂体系，用于聚合物到单体的闭环回收，对于聚合物废物的回收和防止塑料产品的后循环来说，是一项重要但具有挑战性的任务。

该文中，研究人员采用廉价的市售路易斯酸（LA），通过脂肪族聚酯和聚碳酸酯的催化解聚实现批量闭环回收。通过热重分析实验和蒸馏实验筛选了LA的范围。MgCl₂显示出最佳的催化性能，可以在明显低于最高温度的温度下，有效地将11种脂肪族聚酯和聚碳酸酯（即聚己内酯和聚碳酸亚丙酯）解聚成单体（产率高达98%）。

此外，该催化剂体系对（共）聚酯以及聚酯和聚碳酸酯，在其他商品塑料存在下的共混物的解聚，表现出高选择性和兼容性，以及优异的回收和再利用催化剂性能。机理研究表明，单体的闭环回收是通过随机断链和末端基团环化实现的。

附：英文原文

Title: Solvent-Free Chemical Recycling of Polyesters and Polycarbonates by Magnesium-based Lewis Acid Catalyst

Author: Wuchao Zhao, Zongpeng Guo, Jianghua He, Yuetao Zhang

Issue&Volume: 2024-12-24

Abstract: Developing a simple and efficient catalyst system for closed-loop recycling of polymers to monomers is an essentially important but challenging task for the recycle of polymer wastes and preventing the downcycle of plastic products. Herein, we employ inexpensive, commercially available Lewis acids (LAs) to achieve closed-loop recycling in bulk through the catalytic depolymerization of aliphatic polyesters and polycarbonates. The scope of LAs is screened by thermogravimetric analysis experiments and distillation experiments. MgCl2 shows the best catalytic performance that can efficiently depolymerize eleven aliphatic polyesters and polycarbonates (i.e. poly(ε-caprolactone) and poly(trimethylene carbonate)), into monomers (up to 98% yield) at temperatures significantly lower than the ceiling temperature. Moreover, this catalyst system exhibits high selectivity and compatibility towards the depolymerization of (co)polyesters as well as the blends of polyesters and polycarbonates in the presence of other commodity plastics, as well as excellent recycle and reuse catalyst performance. Mechanistic studies indicate that the closed-loop recycling of monomers is achieved through the random chain scission and terminal group cyclization.

DOI: 10.1002/anie.202420688

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202420688