Kinetic study of the oxidation of aliphatic aldehydes bybis(2,2′-bipyridyl) copper(II) permanganate

Abstract

Kinetics of oxidation of aliphatic aldehydes, to the corresponding carboxylic acids, by bis(2,2′-bipyridyl)copper(II) permanganate (BBCP) has been studied. The reaction is first order with respect toBBCP. Michaelis-Menten type kinetics were observed with respect to the aldehyde. The formation constants for the aldehyde-BBCP complexes and the rates of their decomposition, at different temperatures, have been evaluated. Thermodynamic parameters for the complex formation and the activation parameters for their decomposition have also been determined. The reaction is catalysed by hydrogen ions; the acid-dependence being of the form:k obs = a +b [H+]. The oxidation of MeCDO exhibited a substantial kinetic isotope effect (k H/k D = 4.33 at 303 K). The role of aldehyde hydrate in the oxidation process has been discussed. A mechanism involving formation of permanganate ester and its slow decomposition has been proposed.