Process for preparing aromatic amines
View Patent ↗Aromatic amines are produced from aromatic hydrocarbons by a) reacting the aromatic hydrocarbon(s) with a mixture of nitric acid and sulfuric acid to generate a two-phase reaction mixture, b) separating the reaction mixture into an aqueous acid phase and an organic phase containing the nitroaromatic compounds c) washing the organic phase to purify the nitroaromatic compound(s), d) hydrogenating the nitroaromatic compound(s) in the presence of a catalyst to produce the aromatic amine(s) and water of reaction, and e) separating the water of reaction formed in step d) from the aromatic amine(s), in which the water of reaction separated in step e) is used to wash the organic phase containing the nitroaromatic compounds in step c).
1. A process for the production of an aromatic amine comprising:
a) reacting an aromatic hydrocarbon with a mixture of nitric acid and sulfuric acid to form a two-phase reaction mixture,
b) separating the two-phase reaction mixture into an aqueous acid phase and an organic phase containing nitroaromatic compound,
c) washing the organic phase to purify the nitroaromatic compound,
d) hydrogenating the nitroaromatic compound in the presence of a catalyst to produce an aromatic amine and water, and
e) separating the water produced in step d) from the aromatic amine,
in which the water separated in step e) is used to wash the organic phase containing the nitroaromatic compounds in step c).
2. The process of claim 1 in which the water separated in step e) has a concentration of organic compounds of less than 0.1 wt. %.
3. The process of claim 1 in which the water of reaction separated step e) has a concentration of organic compounds of less than 100 ppm.
4. The process of claim 1 in which step c) is performed in two or more stages.
5. The process of claim 4 in which all or some of the water of reaction separated step d) is used in the last wash stage.
6. The process of claim 5 in which the wash water resulting from the last stage is used as wash water in the first wash stage.