Anodic Oxidation of 1-Phenylazo-2-naphthylamine in the Presence of Copper(II) Acetate

Abstract

Anodic oxidation of 1-phenylazo-2-naphthylamine(PANA) dissolved in acetonitrile in the presence of copper(II) salt has been studied. The purpose of this study was to elucidate the electrode reaction of coordinated organic ligand. This paper is the first one in a series of studies based on the same idea. The present reaction system was chosen because this system has been studied in some detail from the standpoint of autooxidation. The present study is composed of two parts, i. e., (1) the studies on the coordination compound formed between PANA and cupric ion in acetonitrile solutions by means of electrochemical as well as absorption spectral methods and (2) the studies on the product obtained by anodic oxidation and also by autooxidation with or without the presence of copper(II) salts. Polarographic studies indicated that one molecule of PANA coordinated to one copper(II) ion while spectral studies indicated that two molecules of the former coordinate to the latter. Although this discrepancy has not been solved yet, it is undoubted that a certain sort of complex compound is formed in the solution. As a result it was confirmed that PANA is oxidized anodically to form a triazole ring which is also formed by autooxidation when copper(II) acetate is present in the solution at a 100% current efficiency. Not only in the absence of acetate but in the presence of copper(II) perchlorate any triazole ring was not formed.