The actual mechanism may not be as simple as implied by this equation, however. For example, Narita and Tezuka (1982) have shown that, in the solution phase oxidation at least, some of the cresol product contains an oxygen atom from the 02. In addition, in the case of reaction of benzene, phenol may be formed by direct displacement of a hydrogen atom by OH (Bjergbakke et al., f 996; Koch, 1997; Pagsberg, 1997).
There are also data suggesting that 02 reacts with the OH-aromatic adduct by abstraction of the hydroxyl hydrogen to give an epoxide that photolyzes to the alcohol. Such epoxides are known to be in equilibrium with the isomeric oxepins. For the benzene reaction, for example, the formation of phenol may occur via the following mechanism:
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