Selective conversion of polyethylene wastes to methylated aromatics through cascade catalysis

Abstract

Upcycling polyethylene into aromatics has attracted much attention for converting plastic wastes into valuable chemicals, but the general routes strongly depend on harsh conditions, precious metals, and/or wide product distributions. Herein, we report the catalytic conversion of polyethylene to methylated aromatics with high yields over the catalysts of aluminosilicate MFI zeolite nanosheets (s-ZSM-5) and mesoporous MFI zeolite modified with zinc species (Zn/meso-ZSM-5) for cascade reactions of polyethylene depolymerization and olefin aromatization, respectively. Following this route, polyethylene was fully converted into C₅₊ products yielding 60.1%, of which 76.7% were aromatics at 400 °C, and 93.4% of the collected aromatics were industrially important methylated aromatics, including toluene, xylene, and mesitylene. This strategy can be extended to convert single-use plastics into methylated aromatics, such as polyethylene bottles, shopping bags, food packages, and DKR-310 plastics.