Bridging barriers: Integrated process intensification and catalytic strategies for valorizing waste polyolefin plastics to hydrocarbon products

Research on chemical recycling of waste plastics has expanded rapidly, yet industrial practice remains dominated by pyrolysis. Moving upcycling toward deployment requires integrated, in-depth analysis. Because polyolefins contain only carbon and hydrogen, this review focuses on reaction routes that convert them into high-value hydrocarbons: ethylene and propylene monomers, long-chain olefins, aromatics, linear alkanes, iso-alkanes and cycloalkanes. These products can displace petroleum-derived feedstocks. For each route, we summarize reaction pathways, catalyst structure–performance relationships, process-intensification strategies, and environmental and economic metrics, including life cycle assessment and techno-economic analysis. We also map how these factors interact. We highlight practical hurdles beyond catalytic activity, catalyst cost, shaping and attrition resistance, and heat and mass transfer limits with high-viscosity feeds. We stress that the resulting hydrocarbons must meet product specifications and gain market acceptance. A whole-process view is therefore essential. Beyond elegant catalytic chemistry, weak links in process engineering must be addressed. In the long term, we propose integrating artificial intelligence and renewable energy into polyolefin recycling factories to accelerate technological innovation and the deep integration of the industrial value chain. This comprehensive analysis identifies the main barriers to scale-up for each high-value pathway. It also offers guidance for applying similar strategies to other plastics and mixed plastic streams.