title: Guaiacol hydrodeoxygenation mechanism on Pt(111): insights from density functional theory and linear free energy relations.
abstract: Density functional theory is used to study the adsorption of guaiacol and its initial hydrodeoxygenation (HDO) reactions on Pt(111). Previous Brønsted-Evans-Polanyi (BEP) correlations for small open-chain molecules are inadequate in estimating the reaction barriers of phenolic compounds except for the side group (methoxy) carbon-dehydrogenation. New BEP relations are established using a select group of phenolic compounds. These relations are applied to construct a potential-energy surface of guaiacol-HDO to catechol. Analysis shows that catechol is mainly produced via dehydrogenation of the methoxy functional group followed by the CHx (x<3) removal of the functional group and hydrogenation of the ring carbon, in contrast to a hypothesis of a direct demethylation path. Dehydroxylation and demethoxylation are slow, implying that phenol is likely produced from catechol but not through its direct dehydroxylation followed by aromatic carbon-ring hydrogenation.
authors.affiliation: Catalysis Center for Energy Innovation, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, 19716 (USA).
authors.forename: Kyungtae
authors.initials: K
authors.lastname: Lee
authors.forename: Geun Ho
authors.initials: GH
authors.lastname: Gu
authors.forename: Charles A
authors.initials: CA
authors.lastname: Mullen
authors.forename: Akwasi A
authors.initials: AA
authors.lastname: Boateng
authors.forename: Dionisios G
authors.initials: DG
authors.lastname: Vlachos
mesh_terms: D000327:Adsorption; D002396:Catechols / Q000737:chemistry; D006139:Guaiacol / Q000737:chemistry*; D006865:Hydrogenation; D008958:Models, Molecular; D008968:Molecular Conformation; D010984:Platinum / Q000737:chemistry*; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D002396:Catechols; D010984:Platinum; D006139:Guaiacol; C034221:catechol
keywords: DFT; biomass; guaiacol; hydrodeoxygenation; platinum