LOW-TEMPERATURE METHOD FOR ANILINE THROUGH HYDROGENATION OF NITROBENZENE Russian patent published in 2008 - IPC C07C209/36 C07C211/46 

FIELD: chemistry.

SUBSTANCE: invention pertains to improved method of obtaining aniline through catalytic hydrogenation of nitrobenzene, by putting trickling gas mixture of reagents onto layer of catalyst so as to form thin film, as well as water and nitrobenzene, at temperature in the catalyst layer of 170-230°C, partly maintained by evaporation of the formed aniline. Passing the trickling gas mixture of nitrobenzene and hydrogen or hydrogen containing gas in the contact zone is usually achieved by mixing nitrobenzene vapour with hydrogen or a hydrogen containing gas, heated to 70-80°C. The trickling gas mixture is preferably formed by spraying nitrobenzene heated to 130-205°C, using atomisers, and hydrogen or hydrogen containing gas at 130-205°C. The process can also be carried out by substituting 15-30% nitrobenzene with aniline. Since considerable heat from the reaction is taken from the working zone of the catalyst due to evaporation of aniline, water and nitrobenzene and excessive heating of their vapours, temperature in the catalyst layer drops sharply and this also allows for removing the remaining heat using a low temperature heat carrier. That way, the low heat load on the contact apparatus allows for eliminating from the process flow scheme an energy intensive, complex and inefficient heating stage and heat removal based on high temperature heat carriers, and the little excess hydrogen is its recycling system.

EFFECT: a better method of obtaining aniline.

5 cl, 9 ex