PNNL

Abstract

Polyvinyl chloride (PVC) and polyolefins are the largest fractions of plastics produced globally, together accounting for approximately 60%. Traditional waste-to-energy methods, such as incineration and pyrolysis, as well as most chemical upcycling methods for PVC utilization, require thorough, high-temperature dechlorination to prevent the release of toxic chlorinated compounds. We present here a strategy for upgrading discarded PVC into chlorine-free fuel range hydrocarbons and HCl in a single-stage process, catalyzed by chloroaluminate ionic liquids. This approach effectively combines endothermic dechlorination and C-C bond cleavage with exothermic alkylation and hydrogen transfer by isobutane or isopentane in a low-temperature tandem process. The light isoalkanes are available via refinery processes and partly via recycling of product stream. The process is suitable for handling real-world mixed and contaminated PVC and polyolefin waste streams, providing an advanced solution for conversion into products compatible with existing refineries.