Efficient selective dehydration of fructose and sucrose into 5-hydroxymethylfurfural (HMF) using dicationic room temperature ionic liquids as a catalyst

Abstract

Abstract Dicationic room temperature ionic liquids (RTILs), with short oligo ethylene glycol linkers have been found to be highly active catalyst for the selective dehydration of fructose and sucrose into 5-hydroxymethylfurfural (HMF). The bis ( N -methylimidazolium) cations containing short oligo ethylene glycol linkers and mesylate (CH 3 SO 3 − ) anions based ILs were employed in catalytic amount for sugar dehydration reactions. As a result, 92.3% of HMF yield was obtained from fructose in 40 min with one equivalent of [TetraEG(mim) 2 ][OMs] 2 at 120 °C. While, 67.2% of HMF was achieved from dehydration of sucrose at 120 °C in 150 min using two equivalents of [TetraEG(mim) 2 ][OMs] 2 . Among those dicationic RTILs, [TetraEG(mim) 2 ][OMs] 2 RTIL was observed to be the most efficient catalyst, demonstrated by its ability to achieve 100% conversion and highest yield of HMF. In addition, effect of reaction time, molar ratio, temperature, and co-catalyst effect were discussed. The use of dicationic RTILs as a catalyst in sugar dehydration greatly reduces the equimolar ratio of catalyst and reaction time required for conversion of sugar into HMF.