Incorporation of tin oxide nanoparticles on sulfonated carbon microspheres as a bifunctional catalyst for efficient conversion of biomass-derived monosaccharides to 5-Hydroxymethylfurfural and furfural

Effective production of versatile platform molecules 5-Hydroxymethylfurfural (HMF) and furfural (FF) from biomass-derived carbohydrates is of great importance to synthesis of high-value-added bio-based chemicals and fuels. In order to highly efficient synthesis of HMF and FF, in this work, by integrating tin oxide nanoparticles with sulfonated carbon microspheres, a novel solid acid catalyst (SnOx-NPs@SC) with tunable Lewis/Brønsted acidity was developed for the conversion of glucose and xylose to HMF and FF, respectively. Characterization and experiment revealed that optimization of Sn precursor dosage and pyrolysis temperature was beneficial to the integration of SnOx with sulfonated carbon microspheres and formation of appropriate acid strength and balanced Lewis/Brønsted acid, which could enhance the selective conversion of glucose and xylose to HMF and FF. In the H2O/THF biphasic solvent system with 1.5 mol/L NaCl, the optimized catalyst (0.35-SnOx-NPs@SC-500) exhibited excellent catalytic performance by achieving 90.2% selectivity of HMF at 180 ℃ for 2 h and 85.4% selectivity of FF at 170 ℃ for 2 h, and displayed relatively high stability in five consecutive experimental cycles. The mechanism was discussed based on the physicochemical properties of the catalyst and reaction system. The results of this work provide an effective strategy for designing a bifunctional solid acid catalyst for the one-pot production of highly value-added biomass intermediates.