One-Pot Conversion of Polyethylene Terephthalate into 1,4-Cyclohexanedicarboxylic Acid without External H₂

Exploring the atom-economic transformation strategy for polyethylene terephthalate (PET), the most staple polyester material, can provide more approaches for the upcycling of plastic waste. Herein, we propose a one-pot process to convert PET into 1,4-cyclohexanedicarboxylic acid (CHDA) via the hydrogenation of terephthalic acid (TPA) by utilizing hydrogen stored in ethylene glycol (EG). The tandem process involving PET depolymerization, EG–H₂O reforming, and TPA hydrogenation achieved high yields of CHDA (>90%) under optimized conditions. The employment of alkaline solution and combination of commercial Ru/C and Pd/C catalysts played critical roles in optimizing the reaction temperature and gaseous components so as to facilitate a one-pot reaction with enhanced hydrogen utilization. This method provides a feasible pathway for upcycling polyester waste, enabling high-selectivity product formation through efficient hydrogen utilization in a one-pot process.