Room-temperature co-upcycling of polyvinyl chloride and polypropylene

Abstract

Co-upcycling of mixed plastics offers a viable approach to reusing carbon resources in plastic wastes and realizing circular economy. However, the presence of polyvinyl chloride (PVC) often complicates the co-upcycling processes, because chlorine (Cl) released from PVC can deactivate catalysts and enter final products. Moreover, existing plastic upcycling processes usually require harsh reaction conditions. Here we present a strategy enabling efficient co-upcycling of PVC and polypropylene (PP) at mild conditions. We use chlorine-resistant ionic liquids butylpyridinium chloride-aluminium chloride to dechlorinate PVC and simultaneously depolymerize the PP–PVC mixture into Cl-free liquid hydrocarbons, with the co-production of hydrogen chloride (HCl) as byproduct. This conversion approach operates at room temperature without the use of external hydrogen or noble metal catalysts. The Cl-free liquid hydrocarbon yield is up to 97.4 wt% of C and H in the feed PP–PVC mixture. This work can incentivize further technical development in plastic upcycling and improve the sustainability of plastic waste management. Upcycling of mixed plastics containing polyvinyl chloride is challenging. This study reports a strategy to co-upcycle polyvinyl chloride with polypropylene to obtain dechlorinated liquid hydrocarbons at high yields at room temperature without the use of external hydrogen or noble metal catalysts.