Selective Conversion of Polyolefin Waste to Branched Alkanes via Methane‐Free Tandem Hydrocracking–Isomerization

ABSTRACT In recent years, catalytic hydrocracking has emerged as a promising waste‐to‐feedstock solution for processing plastic waste. Although ruthenium nanoparticle catalysts exhibit high activity in converting polyolefins into small alkanes, they also tend to produce undesirable methane (CH 4 ) via terminal C─C bond hydrogenolysis. Herein, we report a Ru‐supported sulfated zirconia (RuSZ 1 ) catalyst for the efficient isomerization and hydrocracking of polyolefins without generating CH 4 . Various high‐M w polyethylene and polypropylene samples (up to 1 000 000 g/mol) were fully converted into branched alkanes (C 4 ‐C 20 ). Control experiments using RuSZ 1 revealed negligible scission activity for alkanes with fewer than seven carbons, suggesting that isomerization precedes hydrocracking. Hydrogenolysis to form C 1 and C 2 products is likely inhibited by saturation of sulfate species at the Ru sites, and these products were not observed under any reaction conditions. Full conversion of polyolefins under solvent‐free conditions was achieved, with up to 93% yield of C 3 ‐C 12 alkanes.