ELECTROSYNTHESIS OF 4,4'-DINITROAZOBENZENE FROM PARA-NITROANILINE IN ACETONITRILE WATER MEDIA/

4,4'-Dinitroazobenzene was electrosynthesized from p-nitroaniline at g raphite, (Ir-Ru)O-2, NiCo2O4, PbO2, PdOy and PtOx-coated titanium elec trodes in acetonitrile/water media. The influences of CH3CN volume con tent, OH- concentration, and anolyte temperature on the current effici ency (C.E.) of 4,4'-dinitroazobenzene formation were also investigated . The formation of 4,4'-dinitroazobenzene was found to be mainly depre ssed by the adsorption of a thick organic layer (mainly consisted of 4 ,4'-dinitroazobenzene) on the electrode surface, rendering an increase in electrode potentials during bulk electrolysis, which enhances the evolving rate of oxygen. The low activation energy for the chemical co mbination step of the 4,4'-dinitroazobenzene formation implied that th e intermediate species oxidized from p-nitroaniline possessed radical properties.