Abstract: The electrochemical reduction of 2-chloronitrobenzene was investigated in the room temperature ionic liquid 1-n-butyl-3-methylimidazolium tetrafluorobrate(BMIMBF₄) on a Cu disc microelectrode by using cyclic voltammetry and AC(Alternating Current) impedance method, with some water as the resource of hydrogen. The results show that the electroreduction of 2-chloronitrobenzene is a reaction controlled by diffusion. The AC impedance plots at different potentials show that the reaction is controlled by both electrochemical polarization and diffusion processes, which appears at higher and lower frequencies, respectively. With the increase of applied potentials, the semi-circles appeared at higher frequencies and became smaller and smaller, and it illustrates that the reaction is carried out easier. The influence of electrolysis potential, the concentration of 2-chloronitrobenzene and the passed charge were studied to optimize the electrolytic conditions, with the maximal yield to be 86.2%.

Key words: Ionic liquid, Cyclic voltammetry, AC impedance, Electrochemical impedance spectrscopy, 2-Chloronitrobenzene