Kinetics & Mechanism of Acid Bromate Oxidation of Aliphatic, Aralkyl & Alicyclic Ketones

Abstract

Oxidation of a few typical aliphatic, aralkyl and alicyclic ketones with acid bromate has been investigated. The reaction is first order in both [bromate] and [ketone]. The rate increases with increase in [acid] of the medium. Ionic strength effect is marginal but, the oxidation rates are susceptible to change in dielectric constant of the medium. The mechanism proposed involves the attack of acid bromate on the enol-form of the ketone in the rate-determining, formation of an intermediate followed by a fast decomposition to products. The order of reactivities is: (i) ethyl methyl ketone &gt; <em>n</em>-propyl methyl ketone &gt; dimethyl ketone for simple aliphatic ketones; (ii) acetophenone &gt; propiophenone &gt; butyrophenone for aralkyl ketones; and (iii) cyclooctanone &gt; cyclohexanone &gt; cycloheptanone for alicyclic ketones. Thermodynamic parameters have been evaluated and discussed.