Conversion of carbohydrates into 5-hydroxymethylfurfural in highly concentrated low melting mixtures

Abstract

Highly concentrated melt systems consisting of choline chloride (ChCl) and up to 50 wt% of
carbohydrates, corresponding to carbohydrate concentrations of 2.9 to 3.1 mol/L, have been used
for the conversion of the carbohydrate content into 5-hydroxymethylfurfural (HMF) in the
presence of catalysts. Apart from the monosaccharides D-fructose and D-glucose, the disaccharide
sucrose and the polyfructan inulin were successfully converted into HMF. The reported conditions
with short reaction times at high concentrations may allow for high space-time yields, which may
be of interest for the development of efficient continuous processes for the conversion of
carbohydrates into HMF. In a preliminary ecological evaluation, the ChCl/D-fructose system is
compared to other representative solvents for the synthesis of 5-hydroxymethylfurfural. The melts
have an inherent low toxicological impact due to their negligible vapour pressure.