Kinetics of oxidative hydrolysis of benzaldoximes, acetophenoneoxime and benzophenoneoxime by manganese(III) acetate

Abstract

The kinetics of oxidative hydrolysis of benzaldoximes, acetophenone oximes and benzophenone oximes by manganese(III) acetate have been studied at 28 ± 0.2°C in acetic acid (76%, v/v). Respective aldehydes/ketones are obtained in about 80% yield at ambient temperature. One mole of oxime requires about two moles of Mn^III(OAc)₃ for the reaction. The electronic influence on the rate of Mn^III(OAc)₃ reaction with benzaldoximes is in contrast to polar effect observed on the rate of the reaction with ketoximes as revealed by the change in Hammett reaction constant from - 1.0 to +0.73 and +0.33 respectively. Possibly one electron transfer to Mn^III(OAc)₃ occurs in a slow step in the reactions with aldoximes while the addition of Mn^III(OAc)₃ to C = N bond seems to be rate limiting in the reaction with ketoximes.