ADSORPTIVE STRIPPING VOLTAMMETRY OF CHROMIUM 1,5-DIPHENYLCARBAZONATE

Electrochemical transformations of chromium 1,5-diphenylcarbazonate (the complex), absorbed on the surface of a graphite electrode from a solution of 0.15 M sulfuric acid, were studied. The complex was synthesized by mixing acetone solutions of CrCl3.6H2O and diphenylcarbazone, as well as aqueous solutions of K2Cr2O7 and aqueous acetone solutions of diphenylcarbazide. The complex is absorbed on the electrode over the potential interval 0.55-0.30 V when the circuit is open. In the presence of diphenylcarbazide this interval narrows considerably as a result of competing absorption. Electrochemical reduction of the complex proceeds in stages, with formation of a chromium-containing radical as an intermediate product that is subsequently reduced to diphenylcarbazide, with chromium(III) released to the solution. Absorbed complex is electrochemically oxidized in one stage mainly, with diphenylcarbadiazone formed as the main product.