Synthesis Of The Phenylenediamine

Phenylenediamine is an important organic synthetic intermediate,which is widely used in synthetic pesticides,medicine and rubber et al.However,the synthesis process of phenylenediamine is complex,the separation of nitryl chlorobenzene is difficult and the cost is high.Based on the condition,this paper relates to a process for producing mixed phenylenediamine with mixed nitrochlorobenzenes by ammonolysis and catalytic hydrogenation.In the first step,mixed nitroanilines were synthesized with mixed nitrochlorobenzenes by ammonolysis,during which the effects of the influencing factors,such as time,temperature and concentration of aqueous ammonia etc,on reaction were studied.The results showed that when the reaction time was 10 h,the reaction temperature was 180℃,the concentration of aqueous ammonia was 40%,ammonia ratio was 12 and steirring speed was 500 rpm,the yield of ammonia solution was above 98%.In addition,waste water of ammonolysis was dealt with the adsorption of resin.The results showed that the adsorption rate of the organics was higher than 98%,the COD removal rate of the waste water was higher than 97%,the desorption rate of the organic matter was higher than 96%,when the H103 resin was used to adsorbing the organics of the wastewater.In the second step,mixed phenylenediamines were synthesized with mixed nitroanilines by catalytic hydrogenation.The influence of catalyst,solvent systems,reaction temperature,reaction pressure and steirring speed on the yield of catalytic hydrogenation were studied.The higher than 98% yield of catalytic hydrogenation was obtained when the dosage of the catalyst was 2% of the nitro substrate,the mass ratio of methanol versus water was 1:4,the reaction temperature was 80℃,the reaction pressure was 3.0Mpa and the steirring speed was 500 rpm.Besides,the lifetime of the catalyst was also studied in above conditions.The experimental results showed that the catalyst was recycled by 38 times.In the last,the total yield of the mixed nitroanilines based on the starting nitrochlorobenzenes was higher than 96%.