Kinetic Investigations of Osmium(VIII) Catalysed Oxidation of Thiamine Hydrochloride by Diperiodatocuprate(III) in Aqueous Alkaline Medium

The osmium (VIII) (Os(VIII)) catalysed oxidation of thiamine (TA) by diperiodatocuprate (III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.18 mol dm -3 was investigated spectrophotometrically. 1:3 stoichiometry (thaimine:DPC) exhibited between the reaction of thiamine and DPC was observed in aqueous alkaline medium. The orders of the reaction with respect to [DPC], [Os(VIII)] and [thiamine] were unity, unity and less than unity respectively, in the concentrations range studied. The rate of the reaction increased as the concentration of alkali increased and periodate had retarding effect on the rate of reaction. Ionic strength had a negligible effect on the reaction rate. The main reaction products were identified by spot test and spectroscopic analysis. A mechanism involving reaction paths via free radical was proposed. The activation parameters for the slow step of the mechanism and also the thermodynamic quantities for different steps of mechanism were determined and discussed.

The authors declare no conflict of interest.

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The datasets used in this study are openly available at [repository link] and the source code is available on GitHub at [GitHub link].

This work did not receive any external funding.