We report that molybdenum carbides are selective catalysts for upgrading lignin-derived phenolic monomers, including anisole, m-cresol, 1,2-dimethoxybenzene, and guaiacol, to aromatics with &gt;90% C6+ yield under ambient hydrogen pressure and low temperatures (420–553 K). Kinetic studies of anisole and m-cresol hydrodeoxygenation (HDO) on molybdenum carbides show that high benzene and toluene selectivity (&gt;90% C6+ selectivity) are a result of selective cleavage of aromatic-oxygen bonds (Ar-OH and Ar-OCH3). Low selectivity to sequentially hydrogenated aromatics, cyclohexane and methylcyclohexane, is due to the oxophilicity of molybdenum carbides, which are modified by oxygenates in situ during HDO reactions, as inferred from both transient kinetic studies of anisole HDO and in situ chemical titration studies of aromatic hydrogenation reactions using methanol and water. Metallic sites are required for selective HDO of phenolic compounds as inferred from CO chemical titration under reaction conditions; the number of sites measured by this technique corresponds to ~10% of that measured using ex situ CO chemisorption.

Hydrodeoxygenation of lignin-derived phenolic compounds on transition metal carbides

251st National Meeting (2016)

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