Kinetics and Mechanism of the Oxidation of Aromatic Aldehydes by Hexachloroiridate(IV)

Article abstract of DOI:10.1021/jo00200a005

The kinetics of oxidation of benzaldehyde and some substituted benzaldehydes by hexachloroiridate(IV) have been studied spectrophotometrically in the visible region.The reaction is first order in benzaldehyde and in iridium(IV).The influence of acidity on the reaction is small.The activation parameters of the reaction have been calculated.The oxidation reaction is found to have a deuterium isotope effect, k_H/k_D, of 7.0, indicating that the cleavage of the C-H bond of the aldehyde is the rate-determining step.The reaction appears to be of outer-sphere type and occurs through the intermediate formation of free radicals.