1626-1630The oxidation of various aliphatic alcohols
by ox one catalyzed by Kegin type [CoIIW12O40]6-
has been studied
in a buffer medium of pH = 4. The reaction proceeds by the oxidation of [CoIIW12O40]6- to [CoIIIW12O40]5- by oxone which then oxidizes
the alcohol in a rate determining step generating
alcohol free radical. The reaction is accelerated by increase in the pH of
the solution due to the protonation equilibria of the oxidant. The reaction between
oxone and [CoIIW12O40]6-
has also studied
and is found to proceed in two one-electron steps, involving formation HSO52-
free radical in a slow first step
followed by its reaction with reductant in a fast step. The reaction rate is inhibited
by the [H+] due to protonation equili bria of HSO5-
which is the active species. Decreasing the relative permittivity of the medium
increases the rate of the reaction which is attributed to the formation of an outer-sphere complex between the reactants.
The activation parameters determined for both the reactions support the proposed
mechanisms