Synergistic Co-Upcycling of Polycarbonate and Organophosphate Ester Wastes via Chemically Complementary Reactivity

Abstract

The concurrent accumulation of polycarbonate (PC) plastic and organophosphate esters (OPEs) wastes poses a persistent environmental challenge, as these chemically distinct hazardous streams are conventionally managed through separate, energy-intensive treatment pathways that result in resource loss and secondary pollution. Herein, we report a synergistic co-upcycling strategy that chemically couples these two waste streams within a single catalytic process, transforming them into value-added chemicals with reduced environmental and health risks. Using mild carbonate catalysts, complete depolymerization of PC is achieved concurrently with selective alkylation of the released bisphenol A (BPA), with OPEs serving as in situ alkylating agents. This one-pot process exhibits broad substrate generality across diverse commercial PC wastes and OPEs, affording bisphenol A alkyl ethers in high yields (92-99%). The approach also remains effective in chemically complex matrices representative of industrial waste streams, including trioctyl phosphate solvent waste from anthraquinone-based hydrogen peroxide production and tributyl phosphate extraction waste from metallurgical solvent-extraction operations. A distinguishing feature is the controlled mono-dealkylation of OPEs, exemplified by the quantitative conversion of trimethyl phosphate into dimethyl phosphate, a valuable industrial intermediate, without over-dealkylation. This work demonstrates a waste-towaste co-upcycling approach that leverages chemical complementarity between two hazardous waste streams to reduce environmental burdens while recovering chemical value.