Catalytic Activity of Rhodium (Iii) on Oxidation of Some A–Amino-Acids by Ceric (Iv) in Aqueous Perchloric Acid Medium - A Kinetic and Mechanistic Approach

Jhabbu Prasad*, J. Singh And R.A. Singh

Department of Chemistry, Udai Pratap College, Varanasi - 221 002 (India)

The kinetics of the Rh(III) catalysed oxidation of alanine and valine with Ce(IV) has been studied in perchloric acid medium at different temperatures (25°C-40°C) under the conditions [amino-acid]T >> [Ce(IV)]>>[Rh(III)] T in 1.0 mol dm-3 perchloric acid media. Analysis of the results shows the observed rates of oxidation indicate zero order in [oxidant] and first order dependence on amino acids viz, alanine, valine] respectively. The reaction exhibits first order dependence on Rh(III) and fractional order dependence on the concentration of medium (i.e. HClO4). Variation of ionic strength by adding NaClO4 have no significant effect on the reaction rate. The observation shows that the rate determining step proceeds through an ion-dipole type interaction. A plausible rate law can be proposed as

Catalytic activity; Rh (III); Ce (IV); kinetic and mechanistic approach