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

Abstract

5-Hydroxymethylfurfural (5-HMF) is a value-added versatile platform chemical from renewable biomass resources. 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 Brønsted 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 containing 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.