Journal of Physical Chemistry A, Vol.116, No.12, 3282-3289, 2012
On the Gas-Phase Co+-Mediated Oxidation of Ethane by N2O: A Mechanistic Study
The potential energy surface (PES) corresponding to the Co+-mediated oxidation of ethane by N2O has been investigated by using density functional theory (DFT). After initial N2O reduction by Co+ to CoO+, ethane oxidation by the nascent oxide involves C-H activation followed by two possible pathways, i.e., C-O coupling accounting for ethanol, Co+-mediated beta-H shift giving the energetically favorable product of CoC2H4+ + H2O, with minor CoOH2+ + C2H4. CoC2H4+ could react with another N2O to yield (C2H4)Co+O, which could subsequently undergo a cyclization mechanism accounting for acetaldehyde and oxirane and/or a direct H-abstraction mechansim for ethenol. Loss of oxirane and ethenol is hampered by respective endothermicity and high kinetics barrier, whereas acetaldehyde elimination is much energetically favorable. CoOH2+ could facilely react with N2O to form OCoOH2+, rather than Co(OH)(2)(+) or CoO+.