Catalytic Hydrodeoxygenation of Lignin and Its Model Compounds to Hydrocarbon Fuels over a Metal/Acid Ru/HZSM-5 Catalyst

Abstract

The hydrodeoxygenation (HDO) reaction represents an important process for the high-value utilization of lignin and its model compounds. Here, the Ru/HZSM-5 catalyst containing a large number of acid sites was prepared by an incipient wetness impregnation method. Diphenyl ether (DPE) as a typical model compound in lignin could be completely converted into cyclohexane over the Ru/HZSM-5 catalyst under mild conditions (210 °C, 1 MPa H2, and 2 h). The oxygen atoms in lignin and other model compounds could be also effectively removed via the HDO reaction catalyzed by Ru/HZSM-5 in this study. The coexistence of both the function of Ru metal for hydrogenolysis and acid sites in the pores of HZSM-5 for deoxidation was responsible for the entire HDO reaction. The structure–performance relationship of the Ru/HZSM-5 catalyst in the HDO was investigated and the reaction pathway for the HDO of DPE was analyzed.