The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 04, 2013
Filed:
Aug. 15, 2008
Knut Sommer, Krefeld, DE;
Franz-ulrich Gehlen, Krefeld, DE;
Peter Lehner, Mülheim/Ruhr, DE;
Andre Düx, Brühl, DE;
Benie Marotz, Düsseldorf, DE;
Knut Sommer, Krefeld, DE;
Franz-Ulrich Gehlen, Krefeld, DE;
Peter Lehner, Mülheim/Ruhr, DE;
Andre Düx, Brühl, DE;
Benie Marotz, Düsseldorf, DE;
Bayer MaterialScience AG, Leverkusen, DE;
Abstract
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.