Hydroprocessing of 4-methylanisole as a representative of lignin-derived bio-oils catalyzed by sulphided CoMo/γ-Al2O3: A semi-quantitative reaction network.

Catalytic hydroprocessing of 4-methylanisole as a representative of lignin-derived bio-oils was catalyzed by a commercial sulphided CoMo/γ-Al₂O₃ catalyst in a fixed-bed flow reactor at various space velocities, temperatures, pressures, and feed compositions. An approximate reaction network is presented that accounts for the major products, and approximate kinetics are also presented. The kinetically significant reactions are 4-methylanisole conversion to (a) 4-methylphenol via hydrogenolysis, (b) toluene and benzene via hydrodeoxygenation, (c) cyclohexanone and methylcyclohexanone via hydrogenation, and (d) methylphenol derivatives via alkylation and transalkylation. The formation of toluene and benzene along with water and methanol from 4-methylanisole is inferred to result from direct scission of the C_aromatic-O bond. Cleavage of the C_methyl-O bond is faster than cleavage of the C_aromatic-O bond. The main pathway to toluene formation is the hydrogenolysis of the C_aromatic-O bond of the intermediate 4-methylphenol. [ABSTRACT FROM AUTHOR]