Sulfonic acid-functionalized mesoporous carbon/silica as efficient catalyst for dehydration of fructose into 5-hydroxymethylfurfural

Abstract

Mesoporous silica with desired pore structure (the appropriate channel length and pore size) was synthesized through a modified soft template method. Amorphous carbon layers were then introduced in mesoporous silica channels through infiltration of carbon precursor and carbonization processes. Finally, sulfonic acid groups (–SO₃H) attached onto the amorphous carbons by sulfonation reaction to form sulfonic acid-functionalized mesoporous carbon/silica which was used as a sulfonic acid catalyst. The morphology, pore structure, surface functional groups, and compositions of the obtained sulfonic acid-functionalized mesoporous carbon/silica were investigated by field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption–desorption isotherm, X-ray photoelectron spectroscopy, thermogravimetric analysis and X-ray diffraction techniques. These materials are active for the catalytic dehydration of fructose into 5-hydroxymethylfurfural. The pore structure of hard template-mesoporous silica, and homogeneous coating of amorphous carbon layers are found to be critical to obtain sulfonic acid-functionalized mesoporous carbon/silica with enhanced catalytic activity. The sulfonic acid-functionalized mesoporous carbon/silica synthesized in the desired way could exhibit a high yield of 5-HMF and good recyclability, making them highly applicable in practical applications.