Choline Ionic Liquids as Dual‐Function Solvent‐Catalysts for Mild Upcycling of BPA‐Polycarbonate Into Oil‐Water Separation Resins

ABSTRACT Bisphenol A polycarbonate (BPA‐PC) poses severe environmental risks due to its toxicity and persistence, making the development of efficient upcycling strategies an urgent priority. Herein, we report a green and mild approach for the depolymerization of waste BPA‐PC, using eco‐friendly choline ionic liquids (CILs) as dual‐function solvent‐catalysts without additional organic solvents, and further upcycling the degradation products into a high‐performance oil‐water separation resin. Through systematic screening of CIL structures, alcoholysis reagents and reaction conditions, the choline propionate‐methanol system was identified as the optimal combination, achieving 100% BPA‐PC degradation and a 95% bisphenol A (BPA) yield within 2 h at a mild temperature of 120°C. CILs exhibited excellent recyclability, maintaining high catalytic activity after five cycles for both standard BPA‐PC and real waste polycarbonate buckets. Fourier‐transform infrared (FT‐IR) analysis reveals that the solubilizing effect of CILs on the polycarbonate chain ensures BPA selectivity and minimizes the formation of oligomers. The oil‐water separation resin synthesized from the BPA‐rich degradation products of waste PC buckets achieved an 87.5% dehydration rate for crude oil within 120 min, demonstrating superior water removal performance. This work establishes a sustainable closed‐loop upcycling route for waste BPA‐PC, providing a scalable reference for the valorization of waste polyesters.