Synthesis Of Hydrazobenzene And Its Derivatives

The process for preparation of hydrazobenzene and its derivatives were studied.Hydrazobenzene compounds were synthesized by reducing starting materials nitrobenzene compounds,which were catalyzed and hydrogenated under alkaline condition.We also tried to find out an easy and common synthesis of low cost hydrazobenzene compounds.The catalyst and its amount,different kinds of alkali solutions and their concentrations,reaction temperature,hydrogenation pressure,amount of cocatalyst,different kinds of solvents and concentration were studied. Process parameters were optimized by orthogonal experiment as follows: amount of nitrobenzene 12.3 g(0.1 mol);reaction temperature 30～40℃; concentration of sodium hydroxide solution 25%;amount of cocatalyst 0.1 g.The total yield of hydrogenation is 95.3%.The influence of the cocatalyst was discussed.Experiments showed the effect of cocatalyst is reduced earlier than phenyl hydroxylamine, delaying the formation of the aniline to improve the hydrogenation alternative but not through making the catalyst part poisoned.A series of hydrazobenzene compounds such as 2,2＇-dichlorohydrazobenzene(DHB), 2,2＇-dimethylhydrazobenzene,4,4＇-dimethoxylhydrazobenzene,ect.were synthesized by changing reaction conditions.The mechanism of the reaction was also discussed.