kinetic, mechanistic, and thermodynamic investigations of iridium (iii) catalyzed oxidation of d-mannitol by n-chloro-p-toluenesulfonamide in perchloric acid medium

The present paper deals with the kinetics and mechanism of homogeneously ir(iii) chloride catalyzed oxidation of d-mannitol by chloramine-t [cat] in perchloric acid medium in the temperature range of 30 to 45 °c. the reaction is carried out in the presence of mercuric acetate as a scavenger for chloride ion. the experimental results show first-order kinetics with respect to the oxidant [cat] and catalyst [ir(iii)], while zero-order with respect to substrate, i.e., d-mannitol was observed. the reaction shows negligible effect of [hg(oac)2], [h^+] and ionic strength of the medium. chloride ion positively influences the rate of reaction. the reaction between chloramine-t and d-mannitol in acid medium shows 2:1 stoichiometry. to calculate activation parameters, the reactions have been studied at four different temperatures between 30 to 45 °c. a mechanism involving the complex formation between catalyst and oxidant has been proposed. mannonic acid has been identified chromatographically and spectroscopically as the final product of oxidation of d-mannitol. based on the kinetic data, reaction stoichiometry, and product analysis, a reaction mechanism has been proposed and rate law derived.