The Rate-Limiting Step for Olefin Combustion on Silver: Experiment Compared to Theory

✍ Scribed by J.T. Roberts; R.J. Madix; W.W. Crew

• Book ID: 102968512
• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 538 KB
• Volume: 141
• Category: Article
• ISSN: 0021-9517
• DOI: 10.1006/jcat.1993.1137

✦ Synopsis

The oxidation of propylene by atomically adsorbed oxygen on (\mathrm{Ag}(110)) has been studied over a wide range of oxygen adatom coverages between 0.05 and 0.5 monolayers. Over the entire range of coverage combustion occurs easily, the only products observed are (\mathrm{CO}{2}) and (\mathrm{H}{2} \mathrm{O}), and all absorbed oxygen is found to react readily. The absence of acrolein as a product mitigates against the formation of allyl oxide as a combustion intermediate under these conditions. These results are in contrast to theoretical predictions concerning the mechanism of olefin combustion which invoke both homolytic (\mathrm{C}-\mathrm{H}) cleavage and oxygen insertion into a (\mathrm{C}-\mathrm{H}) bond to produce allyl oxide as an intermediate. Combustion of propylene and higher molecular weight (\mathbf{I})-alkenes is proposed to occur predominantly via an acid-base reaction with chemisorbed oxygen. ₹i 1993 Aciademic Pres., Inc