Bayer Materialscience Ag

Bayer Intellectual Property Gmbh

Franz-Ulrich Gehlen

Stefan Wershofen

Hans-Georg Pirkl

Peter Lehner

Stephan Schubert

Andre Düx

Markus Dugal

Knut Sommer

Karl-Heinz Wilke

Werner Bäcker

Ido Schwarz

Benie Marotz

Andre Lago

Horst Brinkschulte

Susanne Bucholz

Aromatic amines which have been obtained by reduction of aromatic nitro compounds are purified by mixing the crude amine obtained after phase separation with an aqueous, alkali metal hydroxide solution and subsequent distillation of this mixture over a distillation column. The distillation column has at least an upper and a lower rectifying part and a stripping part. The bottom product of the distillation column is partly to completely sluiced out and is partly evaporated in a main evaporator and at least one downstream re-evaporator and partly recycled back into the column.

Process for the purification of aromatic amines

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Krefeld, Germany

Franz-Ulrich Gehlen