Method for starting a reaction during the production of aromatic amines from nitroaromatics

摘要

The present invention relates to a method of producing aromatic amines by hydrogenation of aromatic nitro compounds. This method provides a reactor containing a hydrogenation catalyst; supplies aromatic nitro compounds and hydrogen to the reactor and contacts them with a hydrogenation catalyst, in which the hydrogen which is supplied to the reactor is by a compressor and the compressor contains an operating fluid which at least partially contacts the hydrogen; and regenerates the hydrogenation catalyst by heating and contacting it with oxygen. Particular operating liquids are subsequently exchanged.

主权项

1. A process for preparing aromatic amines by hydrogenation of aromatic nitro compounds, which comprises:
A) providing a reactor with hydrogenation catalyst present therein; B) introducing aromatic nitro compounds and hydrogen into said reactor contacting with said hydrogenation catalyst, wherein at least said hydrogen is fed into the reactor by means of a compressor and said compressor contains an operating liquid which at least partially contacts said hydrogen; C) regenerating said hydrogenation catalyst by heating and contacting with oxygen; wherein D1) at least partially removing liquids which are present in said reactor and/or in plant parts fluidically connected downstream to said reactor and which were at least partly present in said reactor and/or in said plant parts during step C); and/or: D2) at least partially replacing said operating liquid of said compressor which was present in said compressor and/or in recirculation facilities connected to said compressor during step C) by an operating liquid which was not present in said compressor and/or in recirculation facilities connected to said compressor during step C); are carried out after C).