Production of crude 5-hydroxymethylfurfural from glucose by dual catalysts with functional promoters in low-boiling hybrid solvent

5-Hydroxymethylfurfural (5-HMF) is a value-added versatile platform chemical from renewable biomass re-sources. In addition to improving the efficiency of catalysts for glucose conversion in reaction media, the product separation and purification represent another significant barrier in large scale production of 5-HMF. In this work, 5-HMF production from carbohydrates using a combination of Lewis and Bronsted acid catalysts was investigated in a low boiling point solvent consisting of ethylene glycol dimethyl ether (GDE) and water, allowing for feasible recycling of catalysts and product separation. High yield (70%) of 5-HMF from glucose is achieved in the presence of reaction additives, isopropanol (IPA) and NaCl, that help to stabilize 5-HMF and promote fructose dehydration, respectively. The results are validated in larger scale (glucose 140 g, reaction volume 2.2 L). To recover product free of the catalysts, the low-boiling polar solvents are evaporated and the crude product con-taining 80% 5-HMF is recovered by dissolution in a small amount of ethyl acetate (EA) followed by evaporation of EA. This 5-HMF production system offers the advantage of high 5-HMF yield from glucose and the feasibility of product separation.