Process for preparing benzidine by electrolytic process and electrolytic device

The present invention discloses electrolytic process and apparatus for preparing benzidine. Inside conic electrolyzer with ionic film as diaphragm, iron cathode, nickel anode and 10-30 % concentration sodium hydroxide medium, nitrobenzene compound dissolved in xylene solvent and catalyst lead monoxide in 1-15 % of nitrobenzene compound are heated to 50-60 deg.c and DC powered to electrolyze in electrolytic voltage of 1.8-3.6 V and current of 610-960 A while replenishing sodium hydroxide solution to the anode area constantly. After electrolysis, separating xylene solvent, eliminating side product with hydrochloric acid, concentration, cooling to crystallize hydrazinoylene benzene compound, which is then re-arranged with hydrochloric acid to obtain benzidine. The process of the present invention is superior to available electrolysis process with ceramic diaphragm, which is easy to block to cause current and voltage lowering, and is stable, simple and high product purity.