Efficient chemical recycling of mixed plastics by intramolecular glycolysis
Yanfen Wu, Xin Tang, Shuairen Qian, Helai Huang, Yizhen Che, Qikun Hu, Mingze Sun, Yi Cheng, Zhiqiang Niu
Abstract
Abstract Post‐consumer plastic waste is often composed of different types of polymers, making the selective recycling of these mixtures challenging. Herein, we report an intramolecular catalysis for the sequential depolymerization of mixed polycarbonate (PC) and polyesters (polyethylene terephthalate [PET] and polybutylene terephthalate) utilizing a binuclear manganese catalyst. While the conventional glycolysis occurs via an intermolecular nucleophilic substitution, the binuclear catalyst can bind the polymer and ethylene glycol at the adjacent metal sites and induce an intramolecular transesterification pathway, thus exhibiting a rate enhancement of up to 100‐fold compared with the state‐of‐the‐art organocatalysts. This catalyst achieves a turnover frequency of 1564 h −1 for PC and 642 h −1 for PET, the highest value reported to date. This approach facilitates the selective depolymerization of PC/polyesters, achieving a separation efficiency of 99.8% under mild reaction conditions. Life cycle assessment and techno‐economic analysis further demonstrate the sustainability and economic potential of this approach for closed‐loop recycling of waste plastics.