Oxidation, reduction, and condensation of alcohols over (MO3)3 (M = Mo, W) nanoclusters

Zongtang Fang, Zhenjun Li, Matthew S. Kelley, Bruce D. Kay, Shenggang Li, Jamie M. Hennigan, Roger Rousseau, Zdenek Dohnálek, David A. Dixon

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The reactions of deuterated methanol, ethanol, 1-propanol, 1-butanol, 2-propanol, 2-butanol, and tert-butanol over cyclic (MO3)3 (M = Mo, W) clusters were studied experimentally with temperature-programmed desorption and theoretically with coupled cluster CCSD(T) theory and density functional theory. The reactions of two alcohols per M3O9 cluster are required to provide agreement with experiment for D2O release, dehydrogenation, and dehydration. The reaction begins with the elimination of water by proton transfers and forms an intermediate dialkoxy species that can undergo further reaction. Dehydration proceeds by a β-hydrogen transfer to a terminal M = O. Dehydrogenation takes place via an α-hydrogen transfer to an adjacent MoVI = O atom or a WVI metal center with redox involved for M = Mo and no redox for M = W. The two channels have comparable activation energies. H/D exchange to produce alcohols can take place after olefin is released or via the dialkoxy species, depending on the alcohol and the cluster. The Lewis acidity of the metal center with WVI being larger than MoVI results in the increased reactivity of W3O9 over Mo3O9 for dehydrogenation and dehydration. However, the product selection of aldehyde or ketone and olefin is determined by the reducibility of the metal center. Our calculations are consistent with the experiment in terms of the dehydrogenation, dehydration, and H/D exchange reactions. The condensation reaction requires a third alcohol with the sacrifice of an alcohol to form a metal hydroalkoxide, a strong gas-phase Brønsted acid. This Brønsted acid-driven reaction is different from the dehydrogenation and dehydration reactions that are governed by the Lewis acidity of the metal center.

Original languageEnglish
Pages (from-to)22620-22634
Number of pages15
JournalJournal of Physical Chemistry C
Volume118
Issue number39
DOIs
Publication statusPublished - Oct 2 2014

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Nanoclusters
Dehydrogenation
nanoclusters
Dehydration
Condensation
alcohols
Alcohols
condensation
Metals
dehydrogenation
oxidation
Butenes
dehydration
Alkenes
Propanol
Acidity
Olefins
Hydrogen
metals
tert-Butyl Alcohol

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Fang, Z., Li, Z., Kelley, M. S., Kay, B. D., Li, S., Hennigan, J. M., ... Dixon, D. A. (2014). Oxidation, reduction, and condensation of alcohols over (MO3)3 (M = Mo, W) nanoclusters. Journal of Physical Chemistry C, 118(39), 22620-22634. https://doi.org/10.1021/jp5072132

Oxidation, reduction, and condensation of alcohols over (MO3)3 (M = Mo, W) nanoclusters. / Fang, Zongtang; Li, Zhenjun; Kelley, Matthew S.; Kay, Bruce D.; Li, Shenggang; Hennigan, Jamie M.; Rousseau, Roger; Dohnálek, Zdenek; Dixon, David A.

In: Journal of Physical Chemistry C, Vol. 118, No. 39, 02.10.2014, p. 22620-22634.

Research output: Contribution to journalArticle

Fang, Z, Li, Z, Kelley, MS, Kay, BD, Li, S, Hennigan, JM, Rousseau, R, Dohnálek, Z & Dixon, DA 2014, 'Oxidation, reduction, and condensation of alcohols over (MO3)3 (M = Mo, W) nanoclusters', Journal of Physical Chemistry C, vol. 118, no. 39, pp. 22620-22634. https://doi.org/10.1021/jp5072132
Fang, Zongtang ; Li, Zhenjun ; Kelley, Matthew S. ; Kay, Bruce D. ; Li, Shenggang ; Hennigan, Jamie M. ; Rousseau, Roger ; Dohnálek, Zdenek ; Dixon, David A. / Oxidation, reduction, and condensation of alcohols over (MO3)3 (M = Mo, W) nanoclusters. In: Journal of Physical Chemistry C. 2014 ; Vol. 118, No. 39. pp. 22620-22634.
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