Enhanced Production of 5-Hydroxymethylfurfural from Cellulose via Synergistic Catalysis of Solid Acid and Molten Salt Hydrates Solvent

Graphical In this study, a typical Lewis acid Sn-β with low B/L ratio were synthesized and used for one-pot conversion of cellulose into 5-HMF in MSH/acetone system. The addition of Sn-β acid compensates for the Lewis acidity deficiency of MSH and efficiently promoted 5-HMF selectivity. Under the optimized reaction condition, a high 66.88 % yield of 5-HMF was obtained from cellulose conversion. The catalyst maintained a stable 5-HMF conversion rate after three cycles, achieving a direct conversion of cellulose to 5-HMF with excellent industrial application prospects. Producing 5-hydroxymethylfurfural (5-HMF) from abundant and renewable cellulose is a practical method for lignocellulosic biomass valorization. Nonetheless, the high crystallinity of cellulose restricts the accessibility of catalysts, and the complex reaction pathway generally results in the formation of intermediate by-products and 5-HMF degradation. Molten salt hydrates (MSHs) are unique in dissolving crystalline cellulose and their weak Brønsted acidity can facilitate cellulose hydrolysis to glucose. In this work, one-pot conversion of cellulose into 5-HMF was carried out in LiBr MSHs/acetone biphasic system. The solid acid, Sn-β, was used in the conversion to compensate for the shortages of MSH Lewis acidity. Under the optimized reaction condition at 180 °C for 20 min, a high 5-HMF yield of 66.88 % was obtained from cellulose conversion. The influences of reaction conditions on 5-HMF production were studied, and the synergistic effects of solvents and solid acid were established. The catalyzed can be readily recycled and regenerated via calcination. This technique provides a theoretical foundation and technical basis for constructing a one-step conversion of commercial cellulose to value-added 5-HMF, which proposes significant effects on lignocellulose valorization.