Alkaline Ionic Liquids as Catalysts: A Novel and Green Process for the Dehydration of Carbohydrates To Give 5-Hydroxymethylfurfural

An efficient process for the conversion of carbohydrates into 5-hydroxymethylfurfural (5-HMF) catalyzed by the room temperature ionic liquid (IL) 1-butyl-3-methylimidazolium hydroxide ([BMIM]OH), using dimethyl sulfoxide (DMSO) as solvent, has been developed. The yield of 5-HMF obtained by hydrolysis of fructose at 160 °C with a mass ratio IL:fructose of 0.5 was 91.6%. The effects of varying the solvent, IL concentration, temperature, and reaction time on the reaction were studied in detail. The activation energy of fructose conversion was determined to be 99.2 kJ·mol–1, with a pre-exponential factor of 2.1 × 108. Furthermore, the catalyst also exhibited good activity for the dehydration of sucrose to 5-HMF under the same conditions.