KINETICS OF OXIDATION OF CHLOROACETIC ACIDS BY SODIUM N-BROMO-P-TOLUENESULPHONAMIDE (BROMAMINE-T) IN HCL MEDIUM AND CATALYSIS BY RU(III) ION

Kinetics of uncatalysed and Ru(m) catalysed oxidations of mono, di and trichloroacetic acids by bromamine-T (BAT) in acid medium has been st udied at 40 degrees C. The rate laws for the two Paths are rate = k[BA T][H+](x) and rate = [BAT](t)[S](t)[Ru(III)(y)[H+](-z) where x, y and z are less than unity. Added halide ions and the reaction product, tol uenesulphonamide have no effect on the rate. Variation in ionic streng th of medium has no influence on the reaction. The solvent isotope eff ect has been studied in D2O medium. Activation parameters have been ev aluated from the Arrhenius plots. Mechanisms consistent with the exper imental rate laws have been proposed. The protonation constant of mono bromamine-T to form CH3C6H4SO2NH(2)Br is evaluated from the uncatalyse d reaction as 9.3 + 1.0 at 40 degrees C. The value for the same from R u(III) catalysed reaction is 10.3 +/- 1.0. A Taft linear free-energy r elation is noted for the catalysed reaction with rho=1.22 and 0.067 i ndicating that electron withdrawing groups increase the rate. An isoki netic relation is observed with beta=457K showing that enthalpy factor s control the rate of reaction.