Direct Hydrodeoxygenation of Epoxy Resin into Aviation-Fuel-Range Cycloalkanes over Ni/HZSM-5 Catalysts

The upcycling of thermoset epoxy resins remains challenging due to their highly cross-linked and chemically inert network structures. Herein, an efficient catalytic hydrodeoxygenation (HDO) route is developed for the direct conversion of bisphenol A-based epoxy resin into aviation-fuel-range cycloalkanes over Ni/HZSM-5 catalyst. Under mild conditions (220 °C, 4 MPa H2), the optimized 15Ni/HZSM-5(360) catalyst achieves a total cycloalkane yield of 92.4%, with the C15 dicycloalkane propane-2,2-diyldicyclohexane accounting for 78.5%. Systematic tuning of Ni loading and support acidity reveals that a balanced interplay between Ni hydrogenation sites and moderated Brønsted acidity is essential for promoting selective C–O bond scission while suppressing excessive C–C bond scission. Time-dependent product analysis suggests C15 cycloalcohols as key intermediates, elucidating a stepwise depolymerization and HDO pathway. Combined techno-economic analysis and life-cycle assessment further demonstrate the economic competitiveness and environmental viability of this catalytic strategy for epoxy resin waste valorization.