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:
Oct. 25, 1994
Filed:
Apr. 06, 1992
Applicant:
Inventors:
Hartmut Knofel, Odenthal, DE;
Michael Brockelt, Leverkusen, DE;
Marcel Petinaux, Pittsburgh, PA (US);
Rudolf Uchdorf, Krefeld, DE;
Hans-Peter Schal, Dormagen, DE;
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ; C07C / ; C07C / ;
U.S. Cl.
CPC ...
564331 ; 564333 ; 564334 ;
Abstract
The invention relates to an improved process for the production of polynuclear aromatic polyamines by condensation of aniline with formaldehyde in the presence of water and acidic catalysts and working up of the reaction mixture by extraction with a hydrophobic solvent, the acid catalyst accumulating in the aqueous phase of the extraction step being reused.