High aromatics yield (>90%, benzene and toluene) was obtained from vapor phase hydrodeoxygenation (HDO) of phenolic compound mixtures containing m-cresol, anisole, 1,2-dimethoxybenzene, and guaiacol over molybdenum carbide catalysts (Mo2C) under atmospheric pressure at 533-553 K, even with H2 to phenolic compound molar ratios of ∼3,300. Toluene selectivity increased proportionately (4%-66%) to m-cresol content in HDO of phenolic compound mixtures (molar composition: 0%-70%) at quantitative conversion. Phenol selectivity increased with decreasing conversion, implying that the aryl-methoxyl bond in guaiacol is cleaved first, before the aryl-hydroxyl bond. Low selectivity to cyclohexane and methylcyclohexane (<10%) across the conversions investigated (18-94%) demonstrates that undesired successive hydrogenation reactions of aromatics over Mo2C were inhibited, presumably due to in situ oxygen modification, as inferred from titration studies of aromatic hydrogenation reactions using methanol and water as titrants.
Bibliographical noteFunding Information:
This research was supported by Office of Basic Energy Sciences, the U.S. Department of Energy under award number DE-SC0008418 (DOE Early Career Program). We thank Ms. Seema Thakral for assistance with the X-ray diffraction studies.
- Lignin upgrading
- Molybdenum carbide