Catalytic oxidations using cobalt(II) complexes - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 314

The detailed reaction mechanism proposed is shown in Figure 64.
The main mechanistic features of the catalytic oxidation/oxygenation of
2,6-di- tert -butylphenol are analogous to those described earlier 177 .
The phenoxy radical generated by one-electron transfer can be attacked
by either the superoxo complex (oxygenase action) or another

phenoxy radical to form either a adduct or TTBDQ,

respectively.
The adduct releases benzoquinone and yields the species; the
latter abstracts an electron from another phenol molecule, releasing water
and regenerating the

catalyst.