Kinetic studies on the oxidation of diethylenetriaminepentaacetato chromium(III) by periodate

Abstract

The kinetics of the oxidation of diethylenetriaminepentaacetato chromium (III), (Cr(III)-DTPA), by periodate were studied spectrophotometrically over pH range 6.10-7.15 at 14-22oC. The reaction follows first order with respect to Cr(III)DTPA and [IO4-] and inversely dependent on [H+]. The mechanism involves the formation of an intermediate between the monohydroxochromium(III) complex and periodate which decomposes in rate determining step. The values of the intramolecular electron transfer, the formation constant of the intermediate and the hydrolysis constant of the complex were calculated. The activation parameters were calculated.