Carbonaceous microspheres prepared by hydrothermal carbonization of glucose for direct use in catalytic dehydration of fructose

Abstract

A carbonaceous microsphere material was prepared by hydrothermal carbonization (HTC) of glucose, and was used directly for the catalytic dehydration of fructose into 5-HMF without any in situ functionalization or post-modification. The prepared material was found to be a good solid acid catalyst for the production of 5-HMF from fructose in ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), where a 5-HMF yield of 88.1% was obtained at 100 °C for 90 min reaction time, which is due to the contribution of the –COOH groups in the catalyst. It is the first time that a HTC material is reported in the efficient catalytic conversion of biomass without any in situ functionalization or post-modification. In addition, the catalytic system was shown to be applicable to higher fructose concentrations up to ca. 10 wt%. The HTC material catalyst exhibited constant activity for five successive reuses.