Substituents effect on cooxidation rate of chalcones and oxalic acid using chromium (VI)

Yousif Algamal, M. A. Embaby a

Abstract

Chalcones (CHAL)were synthesized from substituted benzaldehyde and acetophenone, benzaldehyde and substituted acetophenone and substituted benzaldehyde and substituted acetophenone subjected to the cooxidation in presence of oxalic acid in aqueous acetic acid medium by chromic acid (Cr (VI)). The reactions were carried out under pseudo–first order condition, and the rate of cooxidation was found to be a unity order with respect to the [Cr (VI)], a fractional order with respect to substituted chalcones and the order with respect to oxalic acid is a fractional order. The effect of various parameter such as [H+], [NaCl],[NaO3],[pyridine]on rate of cooxidation were studied, the dielectric constant of the medium have no effect on reaction rate. Comparative study of the rates of cooxidation of substituted chalcones, were done and shown the presence of electron-releasing group at para position increases the rate of cooxidation and electron-withdrawing group at para position retards the rate of cooxidation