Electrochemical oxidation of propanil and related N-substituted amides

The electrochemical behaviour of propanil and related N-substituted amides (acetanilide and N,N-diphenylacetamide) was studied by cyclic and square wa ve voltammetry using a glassy carbon electrode. Propanil has been found to have chemical stability under the established analytical conditions and sho wed an oxidation peak at +1.27 V versus Ag/AgCl at pH 7.5. N,N-diphenylacet amide has a higher oxidation potential than the other compounds of +1.49 V versus Ag/AgCl. Acetanilide oxidation occurred at a potential similar to th at of propanil, +1.24 V versus Ag/AgCl. These results are in agreement with the substitution pattern of the nitrogen atom of the amide. A degradation product of propanil, 3,4-dichloroaniline (DCA), was also studied, and showe d an oxidation peak at +0.66 V versus Ag/AgCl. A simple and specific quanti tative electroanalytical method is described for the analysis of propanil i n commercial products that contain propanil as the active ingredient, used in the treatment of rice crops in Portugal. (C) 2001 Elsevier Science B.V. All rights reserved.