Kinetic Study of Some Para-Substituted Benzhydrols with Selenium Dioxide

This paper discusses SeO2 led kinetic studies of the oxidation of Þ-Br, Þ-CH3, and Þ-CH3CH2 benzhydrols in aqueous acetic acid medium. The study afforded a good yield of a series of variously p-substituted benzophenones as the oxidation products. The rate of reaction was found to vary as a first-power of concentration of oxidant, substrate and acid. The postulated H2SeO3 + reacting species participated in the reaction mechanism with stoichiometric mole ratio 1:2. The effect of changing dielectric constant of the medium on the rate indicates the reaction to be of dipole-dipole type. The activation parameters are computed for the slow step of the mechanism.

Keywords: p-bromobenzhydrol, p-methylbenzhydrol, p-ethylbenzhydrol, selenium dioxide, inductive effect.