Direct formation of acetate from the partial oxidation of ethylene on a Au/TiO2 catalyst

Isabel Xiaoye Green, Monica McEntee, Wenjie Tang, Matthew Neurock, John T. Yates

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The partial oxidation of ethylene to form adsorbed acetate on a Au/TiO 2 catalyst at temperatures as low as 370 K is reported here using Fourier transform infrared (FTIR) spectroscopy, gas chromatography-mass spectrometry (GC-MS) and density functional theory (DFT) calculations. Ethylene reacts with oxygen on Au/TiO2 to produce acetate on the TiO 2 support as determined by the comparison with a blank TiO 2 and Au/SiO2 catalyst. As shown by DFT calculations, O2 dissociation occurs at the dual-perimeter Au-Ti4+ sites of Au/TiO2 catalysts. Surprising, no ethylene oxide on the catalyst surface or in the gas phase is detected by either FTIR or GC-MS techniques at temperatures up to 673 K. The reaction pathway to ethylene oxide involves a higher barrier (~1.0-1.5 eV) than the pathway for acetate formation (~0.1-0.6 eV). The rate-limiting step to form adsorbed acetate was found to be the protonation of the H2C*C(OH)O*intermediate to produce the bound acetic acid. The theoretical initial deuterium kinetic isotope effect is ~3 which is consistent with the experimental data. Graphical Abstract: [Figure not available: see fulltext.]

Original languageEnglish (US)
Pages (from-to)1512-1524
Number of pages13
JournalTopics in Catalysis
Volume56
Issue number15-17
DOIs
StatePublished - Nov 2013

Keywords

  • Acetate
  • Density functional theory
  • Deuterium kinetic isotope effect
  • Dual catalytic sites
  • Ethylene oxide

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