Selective catalytic degradation of polyethylene by aluminum pyridine-based ionic liquids under mild conditions

Formulating effective strategies for the degradation of polyethylene (PE), a principal constituent of recalcitrant plastic waste, is vital for both scientific advancement and environmental preservation. Herein, a series of aluminum-pyridine ionic liquids were synthesized and employed for the catalytic degradation of PE under mild conditions. The structures and thermal properties of the catalysts were characterized by 1 H NMR, FT-IR, ICP, and TG. The effects of temperature and reaction time on degradation performance were systematically investigated. The results indicate that the unsubstituted pyridine-aluminum ionic liquid exhibited optimal catalytic activity. Under optimized conditions (37 °C, 150 min), the conversion of medium-density polyethylene reached 45.7%, with selectivities of 33.4% for isoalkanes and 24.4% for isodecanes. Furthermore, a plausible carbocation mechanism was proposed to elucidate the reaction pathway. This study provides fundamental insights for addressing the environmental challenges posed by PE waste.