Dehydration of fructose to 5-hydroxymethylfurfural over a mesoporous sulfonated high-crosslinked polymer in different solvents

Abstract

The dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) is a crucial step in the biorefinery process, and finding a recyclable solid-acid catalyst and green solvent remains a challenge. In this work, a mesoporous sulfonated high-crosslinked polymer (abbreviated as SHCP) was synthesized following a facile route and used in the dehydration of fructose to 5-HMF in different solvents. The structure and properties of SHCP were characterized using N₂ adsorption–desorption, XRD, Raman, SEM, TEM, FTIR, ¹³C CP/MAS NMR and XPS techniques. It was confirmed that SHCP possesses high surface area, uniform mesoporous and abundant sulphonic groups, and it can promote the dehydration of fructose to 5-HMF under mild reaction conditions. At the same time, the performance of SHCP in different solvents was tested in detail, it was found that SHCP exhibited similar initial activity in 1,4-dioxane/H₂O mixture as that in dimethyl sulfoxide (DMSO), while the stability of SHCP in 1,4-dioxane/H₂O mixture was enhanced obviously compared with that in DMSO. The reason for the deactivation of SHCP in different solvents was discussed, and it was disclosed that a small amount of water in DIO could depress the oligomerization of 5-HMF and enhance the stability of SHCP.