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:
Dec. 25, 2007
Filed:
Jan. 24, 2007
Berthold Keggenhoff, Krefeld, DE;
Richard Adamson, Leichlingen, DE;
Rudolf Uchdorf, Shanghai, CN;
Fritz Pohl, Brunsbüttel, DE;
Berthold Keggenhoff, Krefeld, DE;
Richard Adamson, Leichlingen, DE;
Rudolf Uchdorf, Shanghai, CN;
Fritz Pohl, Brunsbüttel, DE;
Bayer MaterialScience AG, Leverkusen, DE;
Abstract
The present invention relates to a process for the production of mixtures of di- and polyamines of the diphenylmethane series (MDA) containing less than 1,000 ppm of water and less than 200 ppm of aniline by reaction of aniline and formaldehyde in the presence of acid catalysts and subsequent separation of the acid catalyst and subsequent distillative separation of water and aniline in an at least a two-stage distillation including a flash evaporation and subsequent cooling.