Integrated low-temperature PVC and polyolefin upgrading.

Polyolefins and their chlorinated derivatives such as polyvinyl chloride (PVC) are among the most prevalent plastics in global production and waste streams. 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 hydrogen chloride in a single-stage process catalyzed by chloroaluminate ionic liquids. This approach offsets endothermic dechlorination and carbon-carbon bond cleavage with exothermic alkylation and hydrogen transfer by isobutane or isopentane in a low-temperature tandem process. The light isoalkanes are available from refinery processes and partly from recycling of the product stream. This process is suitable for handling real-world mixed and contaminated PVC and polyolefin waste streams. Editor's summary: Polyvinyl chloride (PVC) is a widely used plastic, particularly in plumbing applications, but its end-of-life processing can produce toxic chlorocarbon compounds, a growing problem as waste continues to accumulate. Zhang et al. report an efficient protocol to remove the chloride in PVC waste as hydrogen chloride using a room-temperature chloroaluminate ionic liquid medium. Mixed-waste streams including polyethylene are also compatible with this chemical process. The carbon chains are concurrently broken down into fuel-range hydrocarbons. —Jake S. Yeston [ABSTRACT FROM AUTHOR]