Hydrodeoxygenation of Furfural over Unsupported, SiO₂-supported or Metal-promoted Mo Carbides: Tunning the Selectivity between 2-Methylfuran and C₁₀ Furoins Diesel Precursors

The hydrodeoxygenation of furfural (FF) over Mo carbides in liquid phase at 200 degrees C, 30 bar of H-2 for 4 h in 2-butanol was investigated. Unsupported and SiO2-supported Mo carbide with different crystallographic phases (beta-Mo2C/SiO2 and alpha-MoC/SiO2), and in the presence of Cu and Ni as promoters were studied. The reactivation treatment under H-2 atmosphere of the passivated Mo carbides was investigated by XAS. The results show that Mo is present in different states of oxidation in the passivated catalysts, with more severe oxidation in the bimetallic systems, in which the original carbides are not restored after reactivation. Finally, the product distribution in the HDO of furfural is modified as a function of catalyst oxidation degree. Using the less oxidized Mo carbide (beta-Mo2C), a higher yield to 2-methylfuran is obtained, while C-10 condensation products are formed for the more oxidized catalysts.