The kinetics of oxidation of benzhydrol and its p-substituted derivatives (YBH, where Cl, Br, NO 2 , CH 3 , and OCH 3 ) by sodium N-chloro-p-toluenesulfonamide or chlor-Y ฯญ H, amine-T (CAT), catalyzed by ruthenium(III) chloride, in the presence of hydrochloric acid in 30% (v/v) MeOH medium has been studied at 35ะC. The reaction rate shows a first-order dependence on [CAT] O and a fractional-order each on [YBH] O , [Ru(III)], and The reaction ฯฉ [H ]
. also has a negative fractional-order (ฯช0.35) behavior in the reduction product of CAT, ptoluenesulfonamide (PTS). The increase in MeOH content of the solvent medium retards the rate. The variation of ionic strength of the medium has negligible effect on the rate. Rate studies in D 2 O medium show that the solvent isotope effect, kะH 2 O/kะD 2 O, is equal to 0.60. Proton inventory studies have been made in H 2 O9 D 2 O mixtures. The rates correlate satisfactorily with Hammett relationship. The LFE relationship plot is biphasic and the reaction constant for electron donating groups and for electron withdrawing ฯญ ฯช2.3 ฯญ ฯช 0.32 groups at 35ะC. Activation parameters โฌH , โฌS , and โฌG have been calculated. The parameters, โฌH and โฌS , are linearly related with an isokinetic temperature indicating โค ฯญ 334 K enthalpy as a controlling factor. A mechanism consistent with the observed kinetics has been proposed.