Kinetic study of ruthenium(III) catalyzed oxidation of proline by bromate in acidic medium

Chemical Laboratories, Feroze Gandhi College, RaeBareli-229 001, India

E-mail : she_ila72@yahoo.com

Manuscript received 12 March 2003, revised 5 August 2003, accepted 8 September 2003

Kinetic investigation on ruthenium(Ill) catalyzed oxidation of proline by acidic solution of potassium bromate in the presence of mercuric acetate as a scavenger for Br^- ion has been made in the temperature range 30-45°. The rate shows zero order kinetics in bromate [$Br{O}_3^{-}$], but order of reaction is one with respect to the substrate and [Ru^III] respectively. Increase in [Cl^-] showed positive effect, while increase in [H⁺] showed negative effect.

Negligible effect of mercuric acetate and ionic strength of the medium is observed. A transient complex, formed between [RuCI₆]^3- and amino acid ([RuCI₆]^3- being reactive species of ruthenium(III) chloride) in 1 : 1 ratio, disproportionates in a slow and rate-determining step. Various activation parameters have been calculated. A suitable mechanism has been proposed.