M. Panda et Sc. Pati, RUTHENIUM(VIII) MEDIATED OXIDATION OF SOME ALIPHATIC AND ALICYCLIC KETONES BY PERIODATE-RUTHENIUM(III) SYSTEM IN AQUEOUS HCLO4 MEDIUM, International journal of chemical kinetics, 28(6), 1996, pp. 453-460
The kinetics of Ruthenium(III) chloride mediated oxidation of acetone,
2-butanone, 4-methyl-2-pentanone, 2-pentanone, cyclopentanone, and cy
clohexanone by sodium periodate in aqueous HClO4 media was zero-order
in [IO4-] and first-order in [ketone]. The reaction was independent of
added [Ru(III)] and showed First-order dependence on [H+] for all the
ketones studied, except acetone. In the case of acetone at [H+] < 0.0
5 M, the rate was independent of [H+], the order in [Ru(III)] being un
ity; but at [H+] > 0.05 M the reaction showed unit dependence on [H+]
and the order in [Ru(III)] was zero. Ruthenium(VIII) generated in situ
is postulated as the hydride abstracting species. A mechanism involvi
ng enolization as the rate determining step is proposed. Acetone at lo
wer acidity of the medium is shown to react directly with Ru(VIII). in
the absence of ruthenium(III) chloride, the kinetics were First-order
in [IO4-], [ketone], and [H+] Structure-reactivity relationship is di
scussed and thermodynamic parameters are reported. (C) 1996 John Wiley
& Sons, Inc.