Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by tetraamminecopper (II) permanganate

The oxidative deoximination of several aldo- and keto-oximes by tetraamminecopper (II) permanganate (TACP), in aqueous acetic acid, exhibits a first order dependence each on both the oxime and TACP. Successive scanning of the reaction mixture has shown the presence of an excellent isosbestic point The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlate well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicates a nucleophilic attack by a permanganate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step, has been proposed.