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:
Jul. 11, 2017
Filed:
Mar. 17, 2009
Stefan Wershofen, Mönchengladbach, DE;
Heinz-herbert Müller, Krefeld, DE;
Richard Adamson, Leichlingen, DE;
Fritz Pohl, Brunsbüttel, DE;
Knut Sommer, Krefeld, DE;
Stefan Wershofen, Mönchengladbach, DE;
Heinz-Herbert Müller, Krefeld, DE;
Richard Adamson, Leichlingen, DE;
Fritz Pohl, Brunsbüttel, DE;
Knut Sommer, Krefeld, DE;
Covestro Deutschland AG, Leverkusen, DE;
Abstract
The present invention relates to a process for producing diamines and polyamines of the diphenylmethane series (MDA) by reacting aniline and formaldehyde in the presence of an acid catalyst, wherein the aniline contains in total less than 0.5 wt. %, based on the total weight of aniline, of one or more compounds which contain at least one carbonyl group or of one or more compounds that are formed by reaction of these compounds which contain at least one carbonyl group with aniline.