Evonik Degussa Gmbh

Evonik Industries Ag

Evonik Operations Gmbh

Pablo Zacchi

Martin Koerfer

Hans Joachim Hasselbach

Stephan Kretz

Caspar Heinrich Finkeldei

Caspar-Heinrich Finkeldei

Dieter Buss

Martin Steurenthaler

Michael R Rinner

Wolfgang Boeck

Benjamin Fonfe

Martin Körfer

Wolfgang Böck

The invention relates to a method for thermally after-burning the waste gas flows developing during the production of acrolein in a gas phase process and for thermally after-burning the waste gas flows developing during the production of hydrocyanic acid in a gas phase process, characterized in that the waste gas flows from the production of acrolein and the waste gas flows from the production of hydrocyanic acid are supplied to a joint thermal after-burning process.

Method for thermally after-burning waste gases from acrolein and hydrocyanic acid production

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 process to produce 3-methylmercaptopropionaldehyde is provided. The process comprises: A) oxidizing a mixture of propylene and inert diluent gases with air over a heterogeneous catalyst to obtain a gaseous oxidation reaction mixture comprising acrolein and by-products; B) quenching the gaseous oxidation reaction mixture to obtain a gas stream comprising acrolein and a quench liquid comprising residual acrolein and the by-products; C) stripping the acrolein from the by-products of the quench liquid and returning the stripped acrolein to the quench; D) absorbing a first portion of the gas stream comprising acrolein from the quench B) in water to obtain an aqueous acrolein solution and an uncondensable gaseous stream comprising inert gases; D1) recycling at least a portion of the uncondensable gaseous stream to the oxidation A) to supply the inert diluent gases; E) distilling the acrolein from the aqueous acrolein solution to obtain an acrolein-free aqueous bottom product; E1) condensing the distilled acrolein; F) reacting the distilled acrolein E1) and the gas stream comprising acrolein B) with methyl mercaptan in a mixture comprising at least one of 3-methylmercaptopropionaldehyde and a hemithioacetal of methyl mercaptan and 3-methylmercaptopropionaldehyde to obtain the 3-methylmercaptopropionaldehyde.

Integrated process for preparing acrolein and 3-methylmercaptopropionaldehyde

A process for preparing methylmercaptopropionaldehyde in a single reaction unit, is provided. According to the preferred embodiment, the process comprises, simultaneously contacting a gaseous mixture comprising acrolein with a liquid mixture comprising methylmercaptopropionaldehyde, methyl mercaptan, a catalyst and methylmercaptopropionaldehyde methyl thiohemiacetal in the reactive absorber; absorbing the acrolein from the gaseous mixture into the liquid mixture; reacting the absorbed acrolein with the methyl mercaptan or the methylmercaptopropionaldehyde methyl thiohemiacetal to obtain methylmercapto-propionaldehyde; removing gaseous impurities and by-products from the liquid mixture; and separating the obtained methylmercaptopropionaldehyde product from the reactive absorber, directing a portion of the separated product to storage or further processing and recycling the remaining portion to the reactive absorber; wherein the methyl mercaptan optionally comprises dimethyl sulfide or dimethyl ether.

Process for preparing methylmercaptopropionaldehyde

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.

Growing community of inventors

Bruchkoebel, Germany

Pablo Zacchi