Regulation of Brønsted acid sites to enhance the decarburization of hexoses to furfural

Abstract

Heterogeneous decarburization of hexose is a promising but challenging route to produce the platform molecule furfural, replacing the traditional production process of dehydration of pentose in homogeneous acid. Herein, H-Beta zeolites with varied Si/Al ratios have been prepared and evaluated to catalyze the decarburization of various hexoses (fructose, glucose, starch and cellulose) to furfural. A synergistic catalytic effect between the *BEA channel and framework-Al was found to be crucial to the formation of linear isomers and the selective cleavage of C–C bonds. Specifically, the *BEA channel favors the formation of the linear hexose isomer, and the framework-Al promotes the decarburization of hexose. Moreover, Brønsted acid was proved to be the active site of C–C bond fracture to generate the C5-intermediate, which promotes the further dehydration to furfural. Among these saccharides, the optimum performance with a FAL yield of 66.0% was obtained from fructose, which is the highest level among previous reports. Notably, a more valuable result of an FAL yield of 32.3% was achieved from cellulose, which is more widespread in nature. This work opens a prospective pathway to produce furfural from sustainable biomass materials.