Efficient Glycolysis of Waste PET at Room Temperature Enabled by a Bifunctional Catalyst System and Co-solvent

Abstract Chemical recycling represents a viable pathway for achieving closed-loop recycling of polyethylene terephthalate (PET). Although numerous chemical recycling methods for PET have been reported, depolymerization at room temperature remains rarely adopted. In this study, waste PET bottle flakes underwent glycolysis assisted by a co-solvent and a bifunctional catalyst system (TFA–TBD–Zn(OAc)2), achieving quantitative PET conversion (100%) and yielding 96.1 and 90.8% bis(2-hydroxyethyl) terephthalate (BHET) under two distinct reaction regimes: 140 °C for 1.5 h and 30 °C for 3 h, respectively. Response surface methodology (RSM) identified temperature and reaction time as the most influential factors affecting glycolysis efficiency under near-ambient conditions (30−50 °C), facilitating the optimization of reaction parameters and elucidation of the reaction mechanism. This integrated approach demonstrates an effective room-temperature chemical recycling strategy for waste PET bottles, significantly enhancing the economic feasibility of industrial-scale polyester recycling.