Reductive Catalytic Upcycling of Polyethylene Using 2-Propanol as Direct Hydrogen-Donor Source

The catalytic upcycling of polyolefins represents a promising strategy for mitigating plastic waste by converting it into valuable liquid hydrocarbons. Herein, we report the reductive upcycling of polyethylene (PE) using a commercial Ru/Al₂O₃ catalyst under an inert atmosphere in the presence of hydrogen-donor alcohols. Among the alcohols tested, 2-propanol (2-PrOH) enabled the highest PE conversion (65%) indicating that external molecular hydrogen is not required under the applied conditions. The process affords high selectivity toward C₁₂– C₂₀ liquid hydrocarbons with minimal gas formation (<5%), with 2-propanol playing a dual role: serving as the reaction medium, thus improving polymer diffusion and mass transfer, and acting as a direct in-situ hydrogen donor. In contrast, negligible conversion was observed in absence of 2-PrOH, highlighting the crucial role of the liquid phase in driving the reductive catalytic upcycling of polyethylene. The method proved to be effective also for real post-consumer polyolefin waste, yielding valuable liquid hydrocarbons from PE-based plastic bags and tissue wrappers. These findings highlight alcohol-mediated catalytic upcycling as a hydrogen-free approach for the valorization of polyolefin waste.