Selective production of 5-hydroxymethylfurfural from fructose in the presence of an acid-functionalized SBA-15 catalyst modified with a sulfoxide polymer

Abstract

Biomass is a renewable carbon feedstock that can be converted to 5-hydroxymethylfurfural (HMF), a useful platform chemical that can be modified to produce valuable chemicals and fuels. Previous research has shown that high HMF selectivity can be achieved in organic solvents such as dimethyl sulfoxide (DMSO) because of its capability to stabilize HMF in solution, but DMSO is an undesirable solvent to use industrially as product separation from the reaction solution is difficult. Surface functionalization of porous catalysts has been shown as a method to introduce solvent-effects at the surface of heterogeneous catalysts, thus avoiding the need for high boiling solvents like DMSO. Poly(ethylene sulfoxide) (PESO) is added to the surface of sulfonic acid (SA) functionalized SBA-15 silica to obtain the bifunctional catalyst SA-PESO-SBA-15. Co-localization of the sulfoxide polymer with sulfonic acid groups inside the catalyst pores (SA-PESO-SBA-15) increased HMF selectivity to 51% from 26% obtained by monofunctional SA-SBA-15 at 27% fructose conversion in water. Additionally, this bifunctional catalyst performs best in 4 : 1 (w/w) THF : water cosolvent, a more industrially preferred cosolvent system, obtaining 79% HMF selectivity at 87% fructose conversion. Overall, these materials are promising for the selective conversion of fructose to HMF.