Unlocking the potential of lignocellulosic biomass in biodiesel production: a novel co-catalytic strategy for one-pot hydrodeoxygenation and esterification of biomass-derived compounds

Abstract

As global energy demand surges and environmental issues from fossil fuels deteriorate, the focus on renewable and eco-friendly energy sources has intensified, with biofuels—especially biodiesel—becoming crucial for the transition to sustainable energy. Unlike traditional biodiesel production relying on esterification and transesterification of oil feedstocks, this study presents a novel conversion route—depolymerization of lignocellulose, condensation of platform compounds, and selective hydrodeoxygenation and esterification (HDOE)—for the production of fatty acid methyl ester (FAME) biodiesel. Based on this technical route, a sulfonated catalyst combined with a hydrogenation metal co-catalyst was developed to successfully tackle the challenges of low selectivity and yield associated with the one-pot HDOE process. The co-catalytic system achieves over 90% yield of FAME from selected biomass-derived long-chain oxygenated compounds with carbon numbers of 7, 8, 10, and 11. Even for more structurally complex C₁₅ substrates, yields still surpass 70%. The acid catalyst significantly influences the reaction by dominating esterification and deoxygenation, while the dual role of methanol is pivotal, facilitating both esterification and the ring-opening of furan derivatives, thereby affecting product selectivity and making it a key determinant of product selectivity. This innovative approach not only explores new potential for the valorization of lignocellulosic biomass waste but also offers a sustainable, green alternative to traditional biodiesel synthesis, advancing the global shift away from fossil fuel dependence.