Kinetic and Mechanistic Study of Oxidation of Phenylacetic Acid by N-Sodio-N-Bromobenzenesulphonamide (Bromamine-B) in Acid Solution : Catalysed by Ru (Iii)

*Mallamma Rangaswamy and S. Ananda

Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore- 570 006 (India)

Kinetics of oxidation of phenyl acetic acid (a-Toluic acid) by Bromoamine-B (BAB) has been investigated at 303 K in acid solution in presence and absence of Ru(III) as catalyst. The oxidation behaviour obeys the rate law, rate = k[BAB][H+] for uncatalyzed reaction of rate = k[BAB][Ru(III)][H+] for catalysed reaction. Added halide ions, the reaction product, benzenesulphonamide, variation of ionic strength and dielectric constant of the medium do not have any significant effect on the rate. The rate of oxidation of phenyl acetic acid by BAB has been studied for various concentrations of Ru(III) at different temperatures and the catalytic constants have been calculated. Activation parameters have been evaluated from Arrhenius plot. A mechanism consistent with experimental results has been proposed.

Phenyl acetic acid; bromamine-B; oxidation; Ru(III)