Aromatic Hydroxylation with an Iron(III)-Catechol-H2O2 System. Mechanistic Implication of the Role of Catechol

Article abstract of DOI:10.1246/bcsj.62.148

The role of catechol in benzene hydroxylation with Fe³⁺/catechol/H2O2 system, the so-called Hamilton system, has been mechanistically investigated by using tiron as a substitute for pyrocatechol.The yield of phenol progresses linearly with reaction time.The phenol yield is dependent on the mole ratio of Fe³⁺ relative to tiron, and the ratio of more than unity is particularly important for the effective functioning of the catalyst system.The o-, m-, and p-product isomer distributions for a few aromatic hydrocarbons are nearly identical with those of the Fenton reaction.These and the separate experimental results are consistent with the mechanism involving the rate-limiting redox reaction between tiron and Fe³⁺ and then the follow-up radical chain sequence as in the Fenton reaction.