Microwave assisted catalytic hydrolysis of fibrous cellulose over framework catalysts: effects of acidity and pore structure

Abstract

Catalytic hydrolysis of fibrous cellulose (CHFC) over framework catalysts (HY zeolites, SBA-15 zeolites and MCM-41) was studied under the microwave (MW) irradiation (MW density of 5 kW/L) at 200 °C. Results showed that CHFC processes were enhanced by the mesoporous catalysts (cellulose conversion of ~ 40%, mcatalyst/mcellulose = 1/1) which is 225% higher than the conversion of catalyst-free system. Pore size and structure of the materials play a dominant role on the catalytic hydrolysis of polymer products and acidity plays a secondary role which will further decompose the secondary products, e.g. decomposing glucose and xylose into 5-HMF, furfural and low molecular acids. The catalyst kept high activity after used three times. The MW assisted CHFC mechanism is accounting for the first step decomposition of cellulose over MW system and then further transformation of short-chain cellulose molecules in the mesopores of the catalysts.