Low Temperature and Efficient Catalytic Depolymerization of Polyethylene Terephthalate Waste

ABSTRACT Polyethylene terephthalate (PET), one of the most extensively manufactured and utilized polyester materials, has inflicted irreversible harm on the ecological environment due to inadequate management. While glycolysis is considered the most attractive chemical recycling strategy for waste PET, existing research faces persistent challenges including high temperatures, strong dependence on metal catalysts, and slow reaction rates. In this work, a low‐temperature, highly efficient metal‐free catalytic system was designed. Acetonitrile was employed as a cosolvent; the activation energy required for the reaction was effectively reduced, enabling the green and efficient depolymerization of waste PET bottles through optimizing the ethylene glycol/acetonitrile (EG/ACN) ratio. The results demonstrated that this catalytic system attained 99.9% PET conversion at just 130°C within 3 h, yielding 81% crystalline bis(2‐hydroxyethyl) terephthalate (BHET) with 97% purity. Furthermore, the use of an organic base catalyst eliminated metal contamination, further enhancing product quality. Consequently, this catalytic system simultaneously fulfills the requirements of low‐temperature, high efficiency, and metal‐free conditions, exhibiting substantial potential for industrial‐scale applications.