Kinetics of oxidation of α,β-unsaturated alcohols by pyridinium bromo chromate

M. Vellaisamy and M. Sharmila

Abstract

Oxidation of α,β- unsaturated alcohols (allyl, crotyl and cinnamyl alcohol) by Pyridinium bromochromate has been studied in 50% acetic acid- water (v/v) medium in the presence of perchloric acid at 303 K. The reaction is first order each in [oxidant] , [substrate] and [H+].Decrease in dielectric constant of the medium increases the rate of the reaction. Increase in ionic strength by the addition of sodium perchlorate has no effect on the rate constant. There is no polymerization with acrylonitrile. The rate of the reaction has been conducted at five different temperatures and activation parameters were calculated. From the observed kinetic results a suitable mechanism with rate data has been proposed. The order of reactivity is Cinnamyl alcohol > Crotyl alcohol > Allyl alcohol.