(703h) Synergistic Catalysis of Metal Salt in Ionic Liquid on the Production of 5-Hydroxymethylfurfural from Glucose

Given the scarcity of fossil fuels and the increasing demand for renewable and sustainable energy sources, there has been a greater focus on converting biomass into valuable products. 5-hydroxymethyl furfural (5-HMF) is a key feedstock for fuel and fine chemical production that can be obtained through the effective conversion of glucose, which has shown promise but remains a significant challenge. In this study, chromium salt and the ionic liquids including [MIM(CH₂)₄HSO₃]⁺X^-, and [MIM]X^- (where MIM represents methylimidazolium and X represents HSO₄^-, Cl^-, Br^-, or I^-) were utilized to develop and optimize a suitable dual-catalyst system for the 5-HMF production with high selectivity. In addition, we investigated the use of several metal chlorides to improve the catalytic efficiency of the ionic liquid-catalyst-glucose conversion systems. The dual catalyst with the highest catalytic activity, CrCl₂-[MIM]HSO₄, selectively converted glucose to 5-HMF in dimethyl sulfoxide (DMSO) at 140 °C. The use of DMSO with high polarity as an organic solvent was chosen since it facilitates solvation with the substrate, enhancing the 5-HMF productivity while lowering costs via reducing the amount of use of ionic liquid. Catalytic activity experiments demonstrate that the structure and properties of the ionic liquids significantly impact the glucose conversion and selectivity of the 5-HMF. This research provides an approach for developing a dual-catalyst system capable of selectively synthesizing 5-HMF from glucose.