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. 13, 1978
Filed:
Dec. 17, 1976
Hartmut Knofel, Leverkusen, DT;
Gunther Ellendt, Krefeld, DT;
Bayer Aktiengesellschaft, Leverkusen, DT;
Abstract
The instant invention is directed to a process for the preparation of multinuclear aromatic polyamines by condensation of aromatic amines with formaldehyde in the presence of aqueous acid catalysts followed by neutralization of the catalyst and processing of the resulting reaction mixture in known manner, characterized in that free amine is removed from the reaction mixture leaving the last condensation stage by means of a hydrophobic solvent, optionally after partial neutralization of the catalyst but before neutralization of the total quantity of catalyst put into the process, and the amine thus removed is returned to the catalyst-containing aqueous phase by return of the resulting amine-containing solvent phase into said aqueous, catalyst-containing phase at any point before the last condensation stage.