52299-08-8

The kinetics of ruthenium(III) catalyzed oxidation of atenolol by diperiodatocuprate(III) in aqueous alkaline medium at a constant ionic strength of I = 0.10 M has been studied spectrophotometrically at 27°C. The reaction between diperiodatocuprate(III) and atenolol in alkaline medium in presence of ruthenium(III) exhibits 2: 1 stoichiometry (atenolol: diperiodatocuprate(III)). The main products were identified by spot test, IR, NMR, and LC-MS. The reaction is of first order in DPC concentrations and has less than unit order in both ATN and alkali concentrations. The order in ruthenium(III) was unity. Intervention of free radicals was observed in the reaction. Increase in periodate concentration decreases the rate. The oxidation reaction in alkaline medium has been shown to proceed via a ruthenium(III)-atenolol complex, which reacts with monoperiodatocuprate(III) in a rate determining step followed by other fast steps to give the products. Probable mechanism is proposed and discussed. The activation parameters with respect to the slow step of the mechanism and thermodynamic quantities were determined and discussed. Pleiades Publishing, Ltd., 2012.

The kinetics of the oxidative degradation of atenolol (ATN) by permanganate in aqueous alkaline medium at constant ionic strength of 0.30 mol dm -3 has been studied spectrophotometrically using a rapid kinetic accessory. The reaction is first order in [permanganate ion] and has less than unit order each in [ATN] and [alkali]. Initial addition of products and change in ionic strength have no significant effect on the reaction rate. However, decrease in dielectric constant of the medium increases the rate. The oxidation in alkaline medium has been shown to proceed via permanganate-atenolol complex, which decomposes slowly in a rate determining step followed by a fast reaction between a free radical of atenolol and another molecule of permanganate species to give the products. The main products have been identified by IR, NMR, fluorimetric and mass spectral studies. The reaction constants involved in the mechanism are evaluated and a good agreement between observed rate constants and the calculated rate constants is obtained. The activation parameters are computed with respect to slow step of the proposed mechanism.

The kinetics of oxidation of atenolol by diperiodatonickelate(IV) (DPN) in aqueous alkaline medium at a constant ionic strength of 1.0 mol dm-3 was studied spectrophotometrically. The reaction is first order in [DPN], less than unit order in [alkali] and zero order in [ATN]. Addition of periodate has no effect on the reaction. Effect of added products, ionic strength and dielectric constant of the reaction medium have been investigated. The main products were identified by I.R., N.M.R., fluorimetry and mass spectral studies. A mechanism involving the deprotonated diperiodatonickelate (IV) (DPN) as the reactive species of the oxidant has been proposed. The reaction constants involved in the different steps of mechanism are calculated. The thermodynamic activation parameters with respect to the slow step of the mechanism are computed and discussed.