Process for the preparation of di- and polyamines from the diphenylmethane series

US9815769B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Thomas Knauf · Dormagen, DE
• Stefan Wershofen · Mönchengladbach, DE
• Klaus-Gerd Gruner · Duisburg, DE
• Esteve Obis Torruella · Tarragona, ES

Key dates

• Filing date: Apr 22, 2014
• Grant date: Nov 14, 2017
• Expiry date: Apr 22, 2034

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G73/0266
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The present invention provides a process for preparing di- and polyamines from the diphenylmethane series by converting aniline and formaldehyde in the absence of an acid catalyst to give aminal and water, removing the aqueous phase and further processing the organic aminal phase to give the di- and polyamines of the diphenylmethane series, in which use of a coalescence aid in the phase separation of the process product obtained in aminal reaction reduces the proportion of water and hence also of water-soluble impurities in the organic phase containing the aminal. The di- and polyamines of the diphenylmethane series obtained by acid-catalyzed rearrangement and workup after further processing of the aminal phase are outstanding suitably for preparation of the corresponding isocyanates.