Kinetics and Mechanism of Oxidation of Iminodiacetatochromium(III) by Periodate

The oxidation of chromium from the trivalent to hexavalent states is an important environmental process because of the high mobility and toxicity of chromium(VI) [1]. Periodate oxidations have been reported to play an important role in biological determinants [2, 3]. They are used to degrade carbohydrate determinants in proteins without altering protein or lipid epitopes [2, 3]. The oxidation of hexacyanoferrate(II) by periodate has been investigated previously in weakly alkaline and neutral phosphate buffer solution and the kinetic were observed to be simple [4]. The oxidation kinetics of hexacyanoferrate(II) by periodate in acetate buffer was also studied [5]. It was reported that the mechanism of oxidation greatly differed on going from alkaline to acidic solution, whereas in acidic solutions the reaction rate was not only independent of periodate, but also inhibited by its increasing concentration. Symons [6] reported that the oxidation of iron(II) by periodate proceeds via a series of one electron-transfer steps. The polymerization of added acrylonitrile was taken as a criterion for the formation Inorganic Reaction Mechanisims, Vol. 6, pp.39-47 © 2006 Old City Publishing, Inc. Reprints available directly from the publisher Published by license under the OCP Science imprint, Photocopying permitted by license only a member of the Old City Publishing Group.