Catalytic Deconstruction of Ethylene Vinyl Acetate Copolymer and Polyethylene Mixtures via Hydroconversion: Challenges and Solutions

We explore hydrogenolysis over ruthenium supported on zirconia (Ru/ZrO2) and hydrocracking over platinum (Pt) supported on zeolites as an effective end-of-life strategy for ethylene vinyl acetate (EVA)─a widely used performance heat sealant in hard-to-recycle multilayer packaging. For Ru/ZrO2 hydrogenolysis, EVA reacts slower than low-density polyethylene (LDPE) and the catalyst deactivates due to carbonaceous deposits originating from polyenes generated in situ during EVA thermal degradation. High H2 pressures and temperatures can overcome catalyst deactivation; however, CH4 yields are excessive due to cascade hydrogenolysis stemming from strong C═C/metal interactions. Polyene hydrogenation allows chains anchored by C═C to desorb from Ru, shifting product selectivity from CH4 to higher-value liquids. Hydrogenolysis of mixed EVA and linear low-density polyethylene (LLDPE), mirroring typical frozen food packaging formulations, results in comparable catalyst activity and CH4 yield as the pure EVA resin. For Pt/zeolite hydrocracking, pure EVA and EVA:LLDPE mixtures are deconstructed to propane or light naphtha with minimal CH4 production. Among catalysts tested, Pt/HY gives the highest liquid productivity (gC5+products/gcat·h). These findings showcase the recalcitrant nature of EVA and its associated mixtures for Ru/ZrO2 hydrogenolysis, highlighting that hydrocracking catalysts may be superior for complex packaging waste.