Methane peroxynitrous acid oxidation

One-electron oxidation. The oxidation of methane with metastable peroxynitrous acid... 

While it is well established that HO—ONO can be involved in such two-electron processes as alkene epoxidation and the oxidation of amines, sulfides and phosphines, the controversy remains concerning the mechanism of HO-ONO oxidation of saturated hydrocarbons. Rank and coworkers advanced the hypothesis that the reactive species in hydrocarbon oxidations by peroxynitrous acid, and in lipid peroxidation in the presence of air, is the discrete hydroxyl radical formed in the homolysis of HO—ONO. The HO—ONO oxidation of methane (equation 7) on the restricted surface with the B3LYP and QCISD methods gave about the same activation energy (31 3 kcalmol" ) irrespective of basis set size . ... 

Recent studies by Bach and coworkers at the B3LYP/6-311- -G(d,p) level also suggest a classical activation barrier for methane oxidation on the restricted ( S > = 0.0), two-electron surface, of AE = 31.1 kcalmol (TS-6r, Figure 11). However, the more important question is whether hydrocarbon oxidation proceeds by a one-electron process involving the metastable form of peroxynitrous acid. 

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