PROCEDEU PENTRU PREPARAREA AMINELOR AROMATICE

摘要

A continuous process for the prepn. of aromatic amines comprises catalystic hydrogenation of mononitro cpds. with the catalyst suspended in the liq. phase which comprises the amine to be produced as a solvent. The amine is recycled to the reactor having a water content below saturation and the amt. recycled is such that the formation of an aq. phase in the reactor is avoided. The process is used esp. for aniline and also for chloroanilines, toluidines, hydrocyanilines and diamines. Previous processes using the amine as solvent have avoided the formation of an aq. phase either by using excess gas, which is costly, or by a higher reaction temp. which leads to more by-prods. and lower productivity. The above provides a simple means of overcoming this problem. Pref. the amt. of amine recycled in ratio to the amine produced is not >10. The recycled amine contains is not >10% water and/or the above ratio is 0.1-10. A pref. process for aniline employs a recycling ratio as above of 0.5-5, esp. 1-1.5, a temp. of 120-150 degrees C and a hydrogen pressure of 10-20 atmos.