Ramachandra, H. and Rangappa, K. S. and Mahadevappa, D. S. (1997) Oxidation of diphenylcarbinols with bromamine-B in acid medium catalyzed by Ru(III), a kinetic and mechanistic study. Oxidation Communications, 20 (4). pp. 565-575.
Full text not available from this repository. (Request a copy)Abstract
The kinetics of oxidation of six p-substituted diphenylcarbinols (Y-DPC, where Y = H, Cl, Br, NO2, CH3 and OCH3) by sodium-N-bromo-benzenesulphonamide or bromamine-B (BAB) in the presence of HCl and catalyzed by RuCl3 in 30% vol. methanol medium has been studied at 35 degrees C. The experimental rate law is, rate = -dBAB]/dt = k'BAB](0)DPC](0)RuCl3](x)H+](y), where x and y are fractions. Addition of reaction product, benzenesulphonamide (ArNH2) retards the reaction. An increase in the dielectric constant of the medium decreases the rate. Rate studies in D2O medium showed that the solvent isotope effect k'(H2O)/k'(D2O) = 0.55. Proton inventory studies have been carried out in H2O-D2O mixtures. The rates correlate satisfactorily with Hammett sigma relationship and plot is biphasic. The reaction constant rho is -2.33 for electron releasing substituents and -0.36 for electron withdrawing groups at 35 degrees C. The activation parameters Delta H*, Delta S*, Delta G* and 1g A are calculated. Delta H* and Delta S* are linearly related and an isokinetic relationship is observed with beta = 329 K indicating enthalpy as a controlling factor.
| Item Type: | Article |
|---|---|
| Subjects: | C Chemical Science > Chemistry |
| Divisions: | Department of > Chemistry |
| Depositing User: | Users 23 not found. |
| Date Deposited: | 27 May 2021 08:46 |
| Last Modified: | 07 Jul 2022 07:59 |
| URI: | http://eprints.uni-mysore.ac.in/id/eprint/16657 |
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