Kinetics and mechanism of iridium(III) chloride catalyzed oxidation of ethylene glycol and methyl glycol by hexacyanoferrate(III) in aqueous alkaline medium

Department of Chemistry. Kanya Gurukul Mahavidhyalaya, Gurukul Kangri University, Jwalapur,

Hardwar-249 407, India

E-mail : dr_anjaligoel@rediffmail.com                 Fax : 91-0133-452290

Chemistry Department, S. D. (P.G.) College, Muzaffernagar-251 001, India

Chemical Laboratories, University of Allahabad, Allahabad-21 1 002, India

Manuscript received 28 July 2000, revised 27 September 2001. accepted 21 March 2002

The iridiurn(III) chloride catalyzed oxidation of ethylene glycol and methyl glycol by alkaline hexacyanoferrate(III) ion is first order at lower concentration of organic substrate and hexacyanoferrate(III) ion, tending towards zero order at their higher concentrations. The order of reaction with respect to hydroxide ion and iridium(III) chloride is unity even upto many folds of variation. The course of reaction has been considered to proceed through the formation of an activated complex between the anion of organic substrate and iridium(III) species. This complex slowly reacts with hexacyanoferrate(III) ion resulting into Irⁱ species and the corresponding intermediate product. The fast oxidation of Ir^l with hexacyanoferrate(III) results Ir^III species and hexacyanoferrate(II).