Process for the preparation of methionine

US9464045B2 · kind B2 · utility

Assignee

• EVONIK DEGUSSA GMBH · DE

Inventors

• Martin Koerfer · Alzenau, DE
• Hans Joachim Hasselbach · Gelnhausen, DE
• Stefan Reichert · Frankfurt, DE
• Harald Jakob · Hasselroth, DE
• Christoph Weckbecker · Gelnhausen, DE
• Klaus Huthmacher · Gelnhausen, DE
• Horst Krull · Hanau, DE
• Bernd Drapal · Alzenau, DE
• Rainer Peter · Hösbach, DE

Key dates

• Filing date: Sep 10, 2015
• Grant date: Oct 11, 2016
• Expiry date: Sep 10, 2035

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/141
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

This disclosure relates to a process for preparing D,L-methionine by feeding carbon dioxide to an aqueous potassium methioninate solution obtained by hydrolysis of 5-(2-methylmercaptoethyl)hydantoin, in order to precipitate out crude methionine, which is separated off and purified. In this process an aqueous solution of the separated-off crude methionine is purified by recrystallization from a solution containing potassium ions and also a crystallization additive. The crystallization additive is a nonionic or anionic surfactant, or a mixture of different nonionic or anionic surfactants. The recrystallization occurs by introducing a 60 to 110° C.-hot methionine solution into a 35 to 80° C.-warm methionine suspension, a temperature of which is lower than that of the introduced solution, such that the temperature of the methionine suspension being maintained between 35 and 80° C. during the addition. The crystallization additive is a sorbitan fatty acid ester or a mixture of different sorbitan fatty acid esters.