Synthesis of high-density and low-freezing-point jet fuel via aldol condensation of lignocellulose-derived vanillin with acetone and subsequent intramolecular cyclization

Abstract

The production of sustainable aviation fuels that simultaneously exhibit high density and low freezing point from renewable resources remains a significant challenge. Herein, an integrated catalytic strategy is developed for the production of highperformance aviation fuel components from lignocellulosic biomass. Lignin-derived vanillin and holocellulose-derived acetone were efficiently coupled via aldol condensation over a heteropoly acid-modified mesoporous catalyst (HPW/Al-MCM-41), affording dehydrozingerone in a high yield of 86.5%. The subsequent hydrodeoxygenation was conducted over a Pt/C and HZSM-5 metal-acid bifunctional catalytic system, enabling effective deoxygenation accompanied by intramolecular alkylation at a mild temperature of 160 °C, selectively producing mixed cycloalkanes dominated by methylindan. The resulting fuel mixture possesses a high density of 0.90 g/mL and a low freezing point of -56.1 °C, significantly outperforming conventional JP-8 fuel. This work demonstrates a lignin-first route for constructing cyclic hydrocarbons and provides new insights into mild-condition upgrading of lignocellulosic feedstocks toward advanced sustainable aviation fuels.