Simultaneous production of furfural and levulinic acid from sugarcane bagasse using a novel, magnetically recoverable tin-based solid acid catalyst in hydrothermal treatment

Catalytic biomass conversion is a crucial pathway for high-value utilization of renewable resources, yet current catalysts face limitations such as insufficient acid sites, poor product selectivity, and low cycling stability. This study developed a magnetic tin-based solid acid catalyst (Fe 3 O 4 @PDA-Sn) using 5-sulfoisophthalic acid sodium salt as a ligand and dopamine hydrochloride-coated Fe 3 O 4 for targeted catalytic conversion of sugarcane bagasse. Results demonstrated that the catalyst achieved a furfural yield of 86.2% and a levulinic acid yield of 32.5% at 170°C for 90 min, with FT-IR, NMR, and XRD confirming its differential deconstruction capability toward cellulose and hemicellulose. Mechanistic analysis demonstrated that the coordinated interaction between Brønsted and Lewis acid sites played a crucial role in steering the reaction toward specific pathways: hemicellulose hydrolysis products underwent dehydration to furfural (enriched in the organic phase), while cellulose was selectively cleaved to form levulinic acid. The catalyst maintained stable performance over 5 cycles without regeneration, with 97.3% magnetic recovery efficiency, offering a novel "facile magnetic separation–excellent cycling performance" strategy for hierarchical biomass conversion. This work provides critical insights into the design of multifunctional biorefinery catalysts for sustainable biomass valorization.