Efficient conversion of glucose and cellulose to 5-hydroxymethylfurfural in DBU-based ionic liquids

Abstract

Development of an efficient catalytic system for the dehydration of carbohydrates to produce 5-hydroxymethylfurfural (HMF), which is a platform molecule for biomass transformation, is a very attractive topic. In this work, three DBU-based ionic liquids (ILs) were prepared and used as the solvent for the conversion of carbohydrates into HMF. It was found that all these new ILs were excellent solvents for the dehydration of glucose, cellulose, fructose, sucrose, inulin, and cellobiose to form HMF using CrCl₃·6H₂O as the catalyst. The effects of temperature, reaction time, catalyst amount, and substrate/solvent weight ratio on the dehydration of glucose in CrCl₃·6H₂O/Bu-DBUCl were studied systematically. It was shown that the yield of HMF could reach 64% from glucose. In addition, the CrCl₃·6H₂O/Bu-DBUCl system could be easily separated from the product, and could be reused five times without considerably decreasing in activity and selectivity.