Abstract
The reactions of C1-C4 aliphatic alcohols over (WO 3) 3 clusters were studied experimentally and theoretically using temperature-programmed desorption, infrared reflection-absorption spectroscopy, and density functional theory. The results reveal that all C1-C4 aliphatic alcohols readily react with (WO 3) 3 clusters by heterolytic cleavage of the RO-H bond to give alkoxy (RO-) bound to W(VI) centers and a proton (H +) attached to the terminal oxygen atom of a tungstyl group (WdO). Two protons adsorbed onto the cluster readily react with the doubly bonded oxygen to from a water molecule that desorbs at 200-300 K and the alkoxy that undergoes decomposition at higher temperatures into the corresponding alkene, aldehyde, and/or ether. Our theory predicts that all three channels proceed over the W(VI) Lewis acid sites with energy barriers of 30-40 kcal/mol, where dehydration is favored over the others. We also present further analysis of the yield and reaction temperature as a function of the alkyl substituents and discuss the origin of the reaction selectivity among the three reaction channels.
Original language | English |
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Pages (from-to) | 9721-9730 |
Number of pages | 10 |
Journal | Journal of Physical Chemistry C |
Volume | 113 |
Issue number | 22 |
DOIs | |
Publication status | Published - Jun 4 2009 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Energy(all)
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films