Kinetics and Mechanism of the Ruthenium (III) Catalysed Oxidation of Some Aliphatic and Cyclic Ketones by Periodate Ion in Aqueous Alkaline Medium: A Novel Behaviour of Ruthenium (III)

Abstract

AbstractKinetics of ruthenium (III) chloride catalysed oxidation of acetone, ethyl methyl ketone, isobutylmethyl ketone, pentan‐2‐one, cyclopentanone and cyclohexanone by sodium metaperiodate in aqueous alkaline medium at constant ionic strength is reported. The order with respect to [IO‐4] is found to be zero. The order with respect to [substrate] is unity for acetone, ethylmethyl ketone, isobutylmethyl ketone and cyclopentanone, whereas, pentan‐2‐one and cyclohexanone exhibit fractional dependence on substrate, in the entire range of substrate concentration studied. Strikingly, the order with resnect to [ruthenium (III)] is fractional in case of the ketones where substrate dependence is unity and Unity where the substrate dependence is fractional.The reaction rate increases linearly following a nearly unit dependence on [OH−] at lower concentration of alkali and levels off after a particular [OH−].The activation parameters have been evaluated. A suitable mechanism has been postulated and rate laws have been deduced.