Kinetics and Mechanism of Oxidation of Aromatic Aldehydes by Imidazolium Dichromate

摘要

The kinetics of oxidation of para and meta-substituted benzaldehydes by imidazolium dichromate has been studied in 70% acetic acid-water medium. The order with respect to substrate and [H+] is found to be unity. The rate increases with the increase in the percentage of acetic acid .An increase of ionic strength has an appreciable effect on the rate. The reaction does not induce polymerisation of acrylonitrile indicating the absence of free radical pathway. The retardation of the rate by the addition of Mn~(2+) ions confirms that a two electron transfer process is involved in the reacion.Electron releasing substituents retard the reaction rate and the electron withdrawing substituents enhace the rate of the reaction. From the kinetic data obtained, the activation paramters have been computed and a suitable mechanism has been proposed.