Promoting the production of 5-hydroxymethylfurfural from glucose via a deep eutectic solvent-dimethyl sulfoxide...

A deep eutectic solvent (DES) composed of SnCl₄·5H₂O and levulinic acid (LVA) was developed and combined with dimethyl sulfoxide (DMSO) to construct an efficient reaction medium for the conversion of glucose into 5-hydroxymethylfurfural (HMF). Under the optimized conditions, the Sn/LVA-16-DMSO binary solvent, coupled with AlCl₃·6H₂O as the catalyst, afforded an HMF yield of 84% at 150 °C within 10 min. The effects of key parameters, including solvent composition, DES molar ratio, catalyst dosage, glucose dosage, reaction temperature, and reaction time, were systematically investigated. Response surface methodology (RSM) revealed that reaction temperature and glucose dosage were the most significant linear factors affecting HMF yield within the studied range. The system also showed acceptable recyclability, as HMF could be extracted from the reaction mixture with a recovery efficiency of 86%, and an HMF yield of 52% was retained after five consecutive cycles. FTIR, DSC, TG, and DTG analyses indicated that the Sn/LVA DES formed a strong hydrogen-bonding network and modified the coordination environment of Sn species, while the combination of DMSO and AlCl₃·6H₂O further provided favorable solvation and Lewis-Brønsted acid synergy for glucose conversion. Compared with previously reported DES-based systems, the present homogeneous DES-DMSO strategy combines a high HMF yield of 84% with a short reaction time of only 10 min, demonstrating an efficient approach for the rapid conversion of glucose to HMF.