Iridium(III) catalyzed oxidation of cyclic ketones by cerium(IV)

Abstract

IrCl 3 which is considered to be a sluggish catalyst in alkaline media, was found to surpass the catalytic efficiency of even osmium and ruthenium in acidic media in the oxidation of cyclopentanone and 2-methylcyclohexanone by cerium(IV) sulphate in aqueous sulphuric acid medium. It was observed that the order of the reaction shows direct proportionality with respect to low concentrations of the oxidant and alcohols, but tends to become independent of concentration at higher concentrations. On increasing the concentrations of externally added Cl À , H þ and Ce III ions, the rate of the reaction decreases sharply initially but the decrease in rate becomes less prominent as their concentration is increased. The rate of reaction is directly proportional with respect to IrCl 3 concentrations. Kinetic data suggest that the production of Ce III ion occurs before the rate-determining step. Parameters such as the energy of activation, free energy of activation and entropy data collected at five different temperatures suggest that cyclopentanone forms the activated complex more easily.

Hexacyanoferrate(III) oxidation of arsenic and its subsequent removal from the spent reaction mixture

“…Iridium(III) chloride has been reported to catalyze the oxidation of organic compounds in acidic medium [8][9][10][11]. To our knowledge, there have been only three uncatalyzed kinetic studies [12][13][14] of the reaction of arsenic(III) with hexacyanoferratre(III) in aqueous alkaline medium and the catalyzed study of the reaction has not been reported till now which prompted us to investigate the kinetics of this reaction both in the presence as well as in the absence of iridium(III) chloride.…”

Iridium(III) catalyzed oxidation of iodide ions in aqueous acidic medium

“…Iridium(III) chloride has been reported to catalyze the oxidation of organic and inorganic compounds [1][2][3][4][5][6][7][8] in acidic [1][2][3][4][5][6] and alkaline [7,8] medium, while hexachloroiridate(IV) has been used as an oxidant for organic [9,10] and inorganic [11,12] compounds. Catalytic nature of iridium(III) chloride in the oxidation of organic compounds by alkaline hexacyanoferrate(III) [7,8,13] was not given much attention due to its sluggish behaviour in alkaline medium.…”