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:
Jan. 03, 2023
Filed:
Jul. 21, 2022
Covestro Llc, Pittsburgh, PA (US);
Covestro Deutschland Ag, Leverkusen, DE;
Richard Adamson, Leichlingen, DE;
Dolan OConnor, Baytown, TX (US);
Stefan Wershofen, Mönchengladbach, DE;
Covestro LLC, Pittsburgh, PA (US);
Covestro Deutschland AG, Leverkusen, DE;
Abstract
The present invention relates to a process for preparing di- and polyamines of the diphenyl methane series. More specifically, the process comprises reacting aniline and formaldehyde by (1a) mixing aniline with hydrochloric acid to form aniline hydrochloride, and (1b) mixing the aniline hydrochloride with a first portion of aqueous formaldehyde; or (1c) mixing aniline with a first portion of aqueous formaldehyde to form an aminal, and (1d) mixing the aminal with hydrochloric acid; to obtain a first reaction product; (2) converting the first reaction product to a second reaction product comprising di- and polyamines of the diphenyl methane series in a cascade of 4 to 25 reaction zones arranged in series, wherein a second portion of aqueous formaldehyde is added to the second of the reaction zones, in which second reaction zone the temperature is equal to or up to 20° C. higher than the temperature in the first reaction zone, and wherein the temperature consecutively increases from the third to the last of the reaction zones, the temperature in the third of the reaction zones being from 15° C. to 50° C. higher than in the second of the reaction zones, and (3) working-up the second reaction product to obtain the di- and polyamines of the diphenyl methane series.