Original scientific paper

Kinetics and Mechanism of Oxidation of Methionine by Chromium(VI): Edta Catalysis

Subbiah Meenakshisundaram ; Department of Chemistry, Annamalai University, Annamalainagar – 608 002, India
Rajagopal Vinothini ; Department of Chemistry, Annamalai University, Annamalainagar – 608 002, India

Abstract

The kinetics of the oxidation of DL-methionine to sulfoxide by CrVI has been studied in aqueous acetic acid in the presence of sodium salt of ethylenediaminetetraacetic acid (edta). It appears that CrVI-edta is the active electrophile. The low dielectric constant of the medium favours the reactivity. Ionic strength and MnII have no significant effect on the conversion. The ratio k(D₂O) / k(H₂O) ≈ 1 does not seem to indicate any significant solvent isotope effect. Highly negative ΔS# values indicate a structured transition state. A ternary intermediate has been envisaged for describing the enhanced reactivity.

Keywords

kinetics; oxidation; edta catalysis; methionine; chromium(VI)

Hrčak ID:

103071

URI

https://hrcak.srce.hr/103071

Publication date:

30.4.2003.

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