Vanadium carbon hydrogen radical

Other works on alkane oxidations in trifluoroacetic acid have been also described [56]. Finally, it has been found that heating an aqueous solution of sodium vanadate in the presence of methane, carbon monoxide and air gives rise to the formation of acetic acid, as well as methanol and formaldehyde in smaller amounts [57]. The yield of CH3COOH attains 3700% based on vanadium after 50 h at 100 °C, the total turnover number being 49. The reaction is sensitive to the pH of the solution. For example, the yields of the products decrease noticeably if pH > 5. The reaction apparently involves hydrogen atom abstraction from methane by a radical or radical-hke species which could be generated via the reduction of V(V) with carbon monoxide. 

Preliminary results of the reaction between vanadium(iii)-tetrasulpho-phthalocyanine complex with oxygen have been reported these data were compared with those obtained for the corresponding reaction of the hexa-aquo complex ion. The oxidation of methyl ethyl ketone by oxygen in the presence of Mn"-phenanthroline complexes has been studied Mn " complexes were detected as intermediates in the reaction and the enolic form of the ketone hydroperoxide decomposed in a free-radical mechanism. In the oxidation of 1,3,5-trimethylcyclohexane, transition-metal [Cu", Co", Ni", and Fe"] laurates act as catalysts and whereas in the absence of these complexes there is pronounced hydroperoxide formation, this falls to a low stationary concentration in the presence of these species, the assumption being made that a metal-hydroperoxide complex is the initiator in the radical reaction. In the case of nickel, the presence of such hydroperoxides is considered to stabilise the Ni"02 complex. Ruthenium(i) chloride complexes in dimethylacetamide are active hydrogenation catalysts for olefinic substrates but in the presence of oxygen, the metal ion is oxidised to ruthenium(m), the reaction proceeding stoicheiometrically. Rhodium(i) carbonyl halides have also been shown to catalyse the oxidation of carbon monoxide to carbon dioxide under acidic conditions ... 

---