Nonphotochemical base-catalyzed hydroxylation of 2,6-dichloroquinone by H2O2 occurs by a radical mechanism.

Kinetic and structural studies have shown that peroxidases are capable of the oxidation of 2,4,6-trichlorophenol (2,4,6-TCP) to 2,6-dichloro-1,4-benzoquinone (2,6-DCQ). Further reactions of 2,6-DCQ in the presence of H(2)O(2) and OH(-) yield 2,6-dichloro-3-hydroxy-1,4-benzoquinone (2,6-DCQOH). The reactions of 2,6-DCQ have been monitored spectroscopically [UV-visible and electron spin resonance (ESR)] and chromatographically.

Revisiting the peroxidase oxidation of 2,4,6-trihalophenols: ESR detection of radical intermediates.

The peroxidase oxidation of 2,4,6-trichlorophenol (TCP) has been clearly shown to result in 2,6-dichloro-1,4-benzoquinone (DCQ). DCQ is a 2-electron oxidation product of TCP that has undergone para dechlorination. Many peroxidases show similar oxidation of the substrate, TCP, to yield the quinone, DCQ.