Microwave-Assisted Conversion of Fructose to 5-Hydroxymethylfurfural Using Sulfonated Porous Carbon Derived from Biomass

In this study, a series of sulfonated carbon solid acid catalysts was prepared by a template method using fructose as the carbon source and zinc chloride as the catalyst and template. The reaction involving fructose dehydration to 5-hydroxymethylfurfural (5-HMF) was investigated using these catalysts with microwave assistance in dimethyl sulfoxide. The influence of different catalysts, catalyst amount, microwave power, fructose content, and reaction temperature, as well as the reusability of the catalyst, were investigated. The prepared catalysts were characterised by X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy, nitrogen adsorption-desorption measurement, and temperature-programmed desorption of ammonia gas, and the total numbers of surface acid sites of these carbon-based solid acid catalysts were analysed by chemical adsorption-desorption of ammonia along with the standard curve for ammonia. The results revealed that the C-2-SO3H catalyst exhibited the best activity. A 5-HMF yield of 87% and fructose conversion of 99% were achieved at 170 degrees C in DMSO after 3 min. The microwave-assisted synthetic strategy was advantageous compared with the traditional method because this approach could shorten the total reaction time.