Exploration on Hydroxymethylation of Furfural to 5-Hydroxymethylfurfural Over Mesoporous Niobium Phosphate Catalyst

Abstract

5-Hydroxymethylfurfural (HMF) is mainly produced by dehydration of hexasaccharides which were limited by the source availability and low yield of the process. Accounting to this, the current study was thus designed to first identify the mesoporous niobium phosphate was a tailored catalyst and further to develop a suitable reaction system for hydroxymethylation of furfural to HMF. The mesoporous niobium phosphate was prepared by a two-step sol–gel hydrothermal method used to catalyze this hydroxymethylation reaction either in a pure water solvent or in an aqueous organic solvent system. Detailed investigation on reaction activity and HMF selectivity was carried out by varying reaction conditions. A highest HMF yield of 51.1% was obtained with a 79.2% furfural conversion under the aqueous dimethyl sulfoxide (DMSO) at 90 °C for 20 h over the current catalyst. Moreover, the mesoporous niobium phosphate could be recovered and reused at least for 6 runs without obvious loss in catalytic activity. Mesoporous niobium phosphate was synthesized by a two-step sol–gel hydrothermal method and firstly investigated for the catalytic hydroxymethylation of furfural to HMF. The results suggest that mesoporous niobium phosphate shows a superior activity and selectivity. The highest yield of 51.1% of HMF was obtained with a 79.2% furfural conversion. The excellent catalytic performance could be attributed to attributed to the strong acid sites and larger porous structure in the catalyst.