Kinetics of the oxidation of benzene-l,4-diol by palladium(II) compounds in aqueous solution

Abstract

Kinetic studies on the oxidation of benzene-l,4-diol (H₂bqn) by palladium(II) compounds in aqueous solution show that the reactions occur in two stages. The first stage involves the conjugate base of a palladium(II) aqua-ion and results in the formation of a palladium(0)–benzoquinone intermediate which then slowly decomposes in the second stage. A palladium(0)–benzoquinone compound has been isolated from reaction mixtures. The reactions are inhibited by chloride ion and show some mechanistic similarities to those in which palladium(II) compounds actas homogeneous catalysts for olefin oxidation.