Process for the preparation of methionine

US9156782B2 · kind B2 · utility

Assignee

• Evonik Industries AG · 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: Feb 26, 2013
• Grant date: Oct 13, 2015
• Expiry date: Feb 26, 2033

Classification

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

Abstract

The invention relates to a process for the preparation of D,L-methionine, in which carbon dioxide is fed 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, where, for the purposes of purification, an aqueous solution of the separated-off crude methionine is prepared and subjected to a recrystallization, characterized in that the solution from which the recrystallization takes place contains potassium ions and also a crystallization additive, where the crystallization additive is a nonionic or anionic surfactant, or a mixture of different nonionic or anionic surfactants, and that the recrystallization takes place by introducing a 60 to 110° C.-hot methionine solution into a 35 to 80° C.-warm methionine suspension, the temperature of which is lower than that of the introduced solution, the temperature of the methionine suspension being maintained between 35 and 80° C. during the addition.