Ruthenium(III)-catalyzed mechanistic studies of oxidation of benzhydrols by sodium N-chloro-p-toluenesulfonamide in HCl medium

Ramachandra, H. and Mahadevappa, D. S. and Rangappa, K. S. and Made Gowda, N. M. (1997) Ruthenium(III)-catalyzed mechanistic studies of oxidation of benzhydrols by sodium N-chloro-p-toluenesulfonamide in HCl medium. International Journal of Chemical Kinetics, 29 (10). pp. 773-780.

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Abstract

The kinetics of oxidation of benzhydrol and its p-substituted derivatives (YBH, where Y = H, Cl, Br, NO2, CH3, and OCH3) by sodium N-chloro-p-toluenesulfonamide or chloramine-T (CAT), catalyzed by ruthenium(III) chloride, in the presence of hydrochloric acid in 30% (v/v) MeOH medium has been studied at 35 degrees C. The reaction rate shows a First-order dependence on CAT](o) and a fractional-order each on YEH](o), Ru(III)], and H+]. The reaction also has a negative fractional-order (-0.35) behavior in the reduction product of CAT, p-toluenesulfonamide (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 D2O medium show that the solvent isotope effect, k'H2O/k'D2O, is equal to 0.60. Proton inventory studies have been made in H2O-D2O mixtures. The rates correlate satisfactorily with Hammett sigma relationship. The LFE relationship plot is biphasic and the reaction constant rho = -2.3 for electron donating groups and rho = -0.32 for electron withdrawing groups at 35 degrees C. Activation parameters Delta H, Delta S, and Delta G have been calculated. The parameters, Delta H and Delta S, are linearly related with an isokinetic temperature beta = 334 K indicating enthalpy as a controlling factor. A mechanism consistent with the observed kinetics has been proposed. (C) 1997 John Wiley & Sons, Inc.

Item Type:	Article
Subjects:	C Chemical Science > Chemistry
Divisions:	Department of > Chemistry
Depositing User:	Users 23 not found.
Date Deposited:	02 Jun 2021 06:46
Last Modified:	04 Jul 2022 09:26
URI:	http://eprints.uni-mysore.ac.in/id/eprint/16601

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