Efficient production of 5-hydroxymethylfurfural from fructose catalyzed by acidic ion-functionalized porous carbon solid acid

Efficient production of 5-hydroxymethylfurfural (5-HMF) from fructose dehydration is a crucial step of biomass to chemicals and fuels. Herein, a strong acidic ion-functionalized porous carbon (PCN-ILSO3CF3) was prepared via bonding with trifluoromethanesulfonic groups for catalyzing fructose dehydration. The various reaction parameters including solvent, catalyst amount, reaction temperature, and time were investigated and showed that the full conversion of fructose with highest 5-HMF yield of 95.6% could be obtained at relatively mild conditions of 110 °C, 50 min in DMSO. The characterization techniques revealed that PCN-ILSO3CF3 possessed the strong Brønsted acid density of 1.25 mmol/g and a porous structure with super-high surface area over 1400 m2/g. Adsorption tests indicated that PCN-ILSO3CF3 was conducive to the adsorption of reactant fructose, but not product of 5-HMF. These characteristics will favor the availability of fructose with the active sites of catalyst, as well as the rapid removal of 5-HMF from the catalyst surface, which had a great contribution to the high selectivity of 95.6%. Moreover, PCN-ILSO3CF3 showed good reusability in reaction with a 5-HMF yield of 84.0% after five runs owing to the stable porous structure and acidic ion groups.