Method for the production of D,L-methionine

US9206121B2 · kind B2 · utility

Assignee

• EVONIK DEGUSSA GMBH · DE

Inventors

• Dieter Buss · Aschaffenburg, DE
• Martin Steurenthaler · Singapore, SG
• Michael R. Rinner · Singapore, SG
• Stephan Kretz · Bad Orb, DE
• Hans Joachim Hasselbach · Gelnhausen, DE
• Caspar-Heinrich Finkeldei · Alzenau, DE
• Martin Koerfer · Alzenau, DE
• Pablo Zacchi · Bad Mergentheim, DE

Key dates

• Filing date: Mar 27, 2015
• Grant date: Dec 8, 2015
• Expiry date: Mar 27, 2035

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C319/20
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A method to produce D,L-Methionine from 2-hydroxy-4-(methylthio)butyronitrile by reaction with ammonia, optionally in the presence of carbon dioxide, is provided. The 2-hydroxy-4-(methylthio)butyronitrile is obtained by reaction of 3-methylmercaptopropionaldehyde with hydrogen cyanide in the presence of a base as catalyst in a main reaction zone of a multizone reactor. Residual gaseous hydrogen cyanide is removed from the main reaction zone to an absorption and post-reaction zone of the reactor which comprises a mixture of 3-methylmercaptopropionaldehyde and the catalyst; and the gaseous hydrogen cyanide is further reacted with the 3-methylmercaptopropionaldehyde in the absorption and post reaction zone. A molar ratio of hydrogen cyanide to 3-(methylthio)propanal in the main reaction zone is from 0.98 to 1.03.