Vapor-phase hydrodeoxygenation (HDO) of anisole over Mo2C catalysts at low temperatures (420-520 K) and ambient pressure showed (1) remarkable selectivity for C-O bond cleavage, giving benzene selectivity >90% among C6+products, (2) high hydrogen efficiency for the HDO reaction as indicated by low cyclohexane selectivity (<9%), and (3) good stability over ∼50 h. Methane selectivity increased at the expense of methanol selectivity as anisole conversion increased, suggesting that the phenolic C-O bond was cleaved preferentially. The concurrent near half-/zero-order dependence of benzene synthesis rates on H2/anisole pressure, and the preferential inhibition of benzene synthesis rates upon introduction of CO relative to isotopic HD exchange suggest that catalytic sites for H2activation are distinct from those required for the activation of anisole. The involvement of metallic sites on Mo2C catalysts for this reaction was demonstrated by the nearly invariant benzene synthesis rate per CO chemisorption site.
Bibliographical noteFunding Information:
This research was supported by Office of Basic Energy Sciences , the U.S. Department of Energy under award number no. DE-SC0008418 (DOE Early Career Program). Part of this work was carried out in the Characterization Facility of the University of Minnesota, which receives partial support from the National Science Foundation through the MRSEC program. We thank Professor Fabio Ribeiro of Purdue University for helpful technical discussions and Mr. Minje Kang for preparing the Pd/Al 2 O 3 catalyst used in this research.
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