Evonik Degussa Gmbh

Caspar-Heinrich Finkeldei

Martin Koerfer

Stephan Kretz

Hans Joachim Hasselbach

Chiu Kee Cheung

Stefan Wenner

Ralf Maassen

Christoph Weckbecker

Dieter Buss

Martin Steurenthaler

Pablo Zacchi

Michael R Rinner

Klaus Huthmacher

Hubert Redlingshöfer

Jan-Olaf Barth

Harald Heinzel

Martin Körfer

Hubert Redlingshoefer

Wolfgang Böck

Geert Van Eester

The present invention relates to a reactor and to a process for synthesis of hydrogen sulphide from elemental sulphur and hydrogen at elevated pressure and elevated temperature. The invention further relates to the use of the reactor for preparation of hydrogen sulphide in high yield and with a low HScontent.

Reactor and process for preparing hydrogen sulphide

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.

Method for the production of D,L-methionine

A method for the production of 2-hydroxy-4-methylthiobutyric acid by hydrolysis of 2-hydroxy-4-(methylthio)butyronitrile is provided. 3-Methylmercaptopropionaldehyde is reacted with hydrogen cyanide in the presence of a base as catalyst in a main reaction zone of the multizone reactor to form a reaction mixture comprising the 2-hydroxy-4-(methylthio)butyronitrile, unreacted 3-methylmercaptopropionaldehyde, the catalyst and residual amounts of gaseous hydrogen cyanide. The 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.

Method for the production of 2-hydroxy-4-(methylthio)butyronitrile from 3-(methylthio)propanal and hydrogen cyanide

A method for the production of 2-hydroxy-4-(methylthio)butyronitrile having good storage stability in a multi-zone reactor, is provided. 3-methylmercaptopropionaldehyde is reacted with hydrogen cyanide in the presence of a base as catalyst in a main reaction zone of the multizone reactor to form a reaction mixture comprising the 2-hydroxy-4-(methylthio)butyronitrile, unreacted 3-methylmercaptopropionaldehyde, the catalyst and residual amounts of gaseous hydrogen cyanide. The 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.

The present invention relates to a process for continuously preparing methyl mercaptan from hydrogen sulphide and methanol in a direct connection with the preparation of hydrogen sulphide.

Process for preparing methyl mercaptan

Provided is a process for continuously preparing methyl mercaptan by reacting a reactant mixture comprising solid, liquid and/or gaseous carbon- and/or hydrogen-containing compounds with air or oxygen, and/or water and sulfur.

Process for continuously preparing methyl mercaptan from carbon- and hydrogen-containing compounds

The invention relates to a reaction vessel in which hydrogen sulphide is prepared from sulphur and hydrogen, wherein the reaction vessel consists partly or entirely of a material which is resistant to the reaction mixture, its compounds or elements and retains its resistance even at high temperatures.

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Alzenau, Germany

Caspar-Heinrich Finkeldei