Liquid-phase dehydration of d-xylose over silica–alumina catalysts with different alumina contents

Abstract

The dehydration of d-xylose into furfural was examined using SiO2–Al2O3 catalysts with varying alumina contents to determine the effects of surface acidity on the catalytic performance. For comparison, SiO2 and Al2O3 catalysts were also examined. d-Xylose conversion increased with increasing alumina content in the SiO2–Al2O3 catalysts. Conversely, furfural selectivity at a similar d-xylose conversion decreased with increasing alumina content in the SiO2–Al2O3 catalyst. Lewis acid sites appeared to catalyze the isomerization of d-xylose into lyxose and xylulose, decomposition of d-xylose into C1–C3 products, and polymerization of d-xylose and furfural into humin.