Abstract: Nitrobenzene was electroreduced to azobenzene in ionic liquid BMimBF4-H2O on Pt electrode at room temperature. The concentrations of nitrobenzene and water in BMimBF4 had complicated influence on the peak potential and peak current of cyclic voltammogram. The results from cyclic voltammetry and constant-potential electrolysis experiments showed that the reaction was a two-molecule and three-step electrochemical process with 8 electrons transferred. In the reaction, anion radical arose in first step, 2 electrons were transferred in second step and accompanied with coupling reaction of radicals, 2 electrons were transferred in third step, and azobenzene was produced.

Key words: Nitrobenzene, Ionic liquid, Water, Electroreduction