The electroreduction of technological solutions of a sodium salt of 4-nitrosodiphenylamine with a continuous extraction of formed 4-aminodiphenylamine into a water-immiscible solvent and a separation of the latter, leaves a solution containing alkali, sodium chloride, methanol, and admixtures of the initial and target compounds. Freed from the methanol, the solution may serve as anolyte in the salt electroreduction, instead of an alkali solution used for the purpose. The most suitable anode material is titanium covered with platinum or iridium. Anodically treated solutions are colorless and contain no initial and target substances but include oxygen compounds of chlorine. The formation of the compounds may be avoided by introducing 10–4 M Co2+ into solution. The ions may be used repeatedly.