Abstract

KINETICS AND MECHANISM OF RUTHENIUM (III) CATALYZED OXIDATION OF ASPIRIN BY CHLORAMIN-T: IN ACIDIC MEDIUM

Amrita Srivastava and *Neha Agarwal

Abstract

The present paper deals with the kinetics and mechanism of Ru(III) catalysed oxidation of Aspirin by Chloramine-T (CAT) in aqueous acidic medium at 313 K. The experimental results confirm first order dependence on Aspirin, first order dependence on catalyst i.e Ru(III) and Zero order dependence on oxidant and hydrogen ion concentration. Variation of Ionic strength (I) and addition of halide ion had no significant effect on the reaction rate. The rate of reaction increased with the successive addition of CH3COOH indicated negative dielectric effect on the rate of reaction. The oxidation product has been identified by UV and FTIR spectroscopic techniques. A suitable mechanism has been proposed which explains the observed orders and kinetic observations. The reaction proceeds through the formation of oxidant-catalyst complex which decomposes in the slow step providing reduced species of oxidant and the catalyst is separated. The activation parameters with respect to slow step of the mechanism are computed and various thermodynamic parameters are also determined. The rate law has been derived on the basis of obtained data.

Keywords: Aspirin, Kinetics, Oxidation, Ru(III) Chloride, Chloramine-T.