Efficient Conversion of Biomass-Derived Saccharides to Levulinic Acid Using Silicotungstic Acid

The conversion of biomass-derived saccharides into platform chemicals is of immense importance for biorefineries. This study demonstrated the potential of using heteropoly acid as a catalyst in a green solvent system composed of γ-valerolactone and water for the production of levulinic acid from biomass-derived saccharides. The effects of heteropoly acids with different central heteroatoms (P and Si) and addendum atoms (W and Mo) on the catalytic conversion of glucose to levulinic acid in the γ-valerolactone–water system were studied. According to the experimental results, silicotungstic acid had the highest catalytic activity. In comparison to other catalysts, silicotungstic-acid-catalyzed glucose conversion could obtain the highest levulinic acid yield under the same reaction conditions, which was mainly attributed to the lower ratio of Brønsted/Lewis acid of silicotungstic acid. In optimal circumstances, 87.7% levulinic acid was obtained by glucose conversion at 190 °C and 60 min. Meanwhile, non-protonic polar solvent γ-valerolactone could promote the slight conversion of glucose to pentose, producing about 9% furfural. In addition, a kinetic model was established to further evaluate the reaction process of glucose conversion to levulinic acid and furfural. The green reaction system was also appropriate for other saccharides. In this study, a new approach could be provided to efficiently convert saccharides into platform chemicals.