The reactions of hydrocarbons and carboxylic acids on Fe(100) were studied by temperatureprogrammed reaction spectroscopy (TPRS) and X-ray photoelectron spectroscopy (XPS). Adsorbed methyl groups were observed to be stable surface intermediates formed from CH3Cl adsorption. The methyl groups reacted to form H2 and surface carbide; the rate of this reaction was given by −dσCH3 /dt = (8 × 1012 s−1)σCH3 exp(− 110 kJ/mole/RT). TPRS results did show that oleflns formed stable surface intermediates, though no definitive identification was possible from the studies reported here. Carboxylic acids were found to form stable carboxylate intermediates, which decomposed by first-order kinetics to form H2 and either CO2 or CO and adsorbed oxygen. The rates for formate and acetate decomposition were −dσHCOO/dt = (7 × 1013s−1)σHCOOexp (−130 kJ/mole/RT), −dσCH3COO/dt = (8 × 1013s−1)σCH3COOexp(−140 kJ/mole/RT). The stability of surface formates on various metal surfaces were compared and shown to correlate with the oxygen metal bond strength.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry