Ruthenium(III) mediated Oxidation of Tripelennamine hydrochloride by Cerium(IV) in Aqueous Sulfuric Acid Medium: A Kinetic and Mechanistic Approach

The micro amounts (10^-5 mol dm^-3) of ruthenium(III) mediated oxidation of tripelennamine hydrochloride by cerium(IV) in aqueous sulfuric acid medium is studied spectrophotometrically at 25°C and at I = 0.16 mol dm^-3. The observed stoichiometry is 1:2, [TPA]: [Ce(IV)]. The oxidation products were identified by spot test and TLC techniques and characterized by IR and GC-MS spectra. The reaction showed first order kinetics in cerium(IV), ruthenium(III) concentration and an apparent less than unit order dependence in tripelennamine hydrochloride concentration. Increase in sulphuric acid concentration decrease the rate of reaction. The active species of oxidant and catalyst are Ce(OH)^3+ and [Ru(H2O)6]^3+ respectively. Based on experimental results a possible mechanism is proposed and suitable rate law is derived. The reaction constants involved in the mechanism are calculated by using these constants, theoretical rate constants are calculated and are in good agreement with experimental values under different experimental conditions. The activation parameters are also calculated with respect to the slow step of the proposed mechanism.