Abstract: The present invention relates to a process for the preparation of methionine comprising the step of contacting a solution or suspension comprising 2-amino-4-(methylthio)butanenitrile and/or 2-amino-4-(methylthio)butaneamide with water in the presence of a catalyst to give a methionine comprising mixture, wherein the catalyst comprises CeO2 comprising particles, wherein the CeO2 comprising particles have a BET surface area of from 175 to 300+/?10% m2/g measured according to DIN ISO 9277-5 (2003), a mean maximum Feret diameter xFmax, mean of from 3+/?10% to 40+/?10% nm and a mean minimum Feret diameter xFmin, mean of from 2+/?10% to 30+/?10% nm, both measured according to DIN ISO 9276-6 (2012).

Abstract: The present invention relates to a process for the preparation of methionine comprising the step of contacting a solution or suspension comprising 2-amino-4-(methylthio)butanenitrile and/or 2-amino-4-(methylthio)butaneamide with water in the presence of a catalyst to give a methionine comprising mixture, wherein the catalyst comprises CeO2 comprising particles, wherein the CeO2 comprising particles comprise from 50 to 100 wt.-% of CeO2, have a BET surface area of from 35 to 65 m2/g measured according to DIN ISO 9277-5 (2003), a mean maximum Feret diameter xFmax, mean of from 10 to 40 nm and a mean minimum Feret diameter xFmin, mean of from 5 to 30 nm, both measured according to DIN ISO 9276-6 (2012).

Abstract: The present invention relates to a process for the preparation of methionine comprising the step of contacting a solution or suspension comprising 2-amino-4-(methylthio)butanenitrile and/or 2-amino-4-(methylthio)butaneamide with water in the presence of a catalyst to give a methionine comprising mixture, wherein the catalyst comprises CeO2 comprising particles, wherein the CeO2 comprising particles have a BET surface area of from 175 to 300+/?10% m2/g measured according to DIN ISO 9277-5 (2003), a mean maximum Feret diameter xFmax, mean of from 3+/?10% to 40+/?10% nm and a mean minimum Feret diameter xFmin, mean of from 2+/?10% to 30+/?10% nm, both measured according to DIN ISO 9276-6 (2012).

Abstract: The invention refers to the use of a particulate catalyst containing 60.0 to 99.5 wt. % ZrO2 stabilised with an oxide of the element Hf and at least one oxide of the element M, wherein M=Ce, Si, Ti, or Y, for the hydrolysis reaction of methionine amide to methionine, wherein the median particle size x50 of the particulate catalyst is in the range of from 0.8 to 9.0 mm, preferably of from 1.0 to 7.0 mm. The invention also refers to a process for preparing methionine comprising a step of contacting a solution or suspension comprising methionine amide and water with said particulate catalyst to provide a reaction mixture comprising methionine and/or its ammonium salt from which methionine can be isolated.

Abstract: The present invention relates to a process for the preparation of methionine comprising the step of contacting a solution or suspension comprising 2-amino-4-(methylthio)butanenitrile and/or 2-amino-4-(methylthio)butaneamide with water in the presence of a catalyst to give a methionine comprising mixture, wherein the catalyst comprises CeO2 comprising particles, wherein the CeO2 comprising particles comprise from 50 to 100 wt.-% of CeO2, have a BET surface area of from 35 to 65 m2/g measured according to DIN ISO 9277-5 (2003), a mean maximum Feret diameter xFmax, mean of from 10 to 40 nm and a mean minimum Feret diameter xFmin, mean of from 5 to 30 nm, both measured according to DIN ISO 9276-6 (2012).

Abstract: The invention relates to a process for preparing 2,6-bis(methionyl)-1,4-dketopiperazine, comprising the following steps: a) heating a reaction mixture comprising methionine and polar protic solvent at a temperature of less than 170.0° C., while passing an inert gas stream over or through the reaction mixture; b) obtaining 2,6-bis(methionyl)-1,4-diketopiperazine.

Abstract: The invention relates to a method for production of D- and/or L-methionine via D- and/or L-homoserine with subsequent chemical transformation to give methionine.

Abstract: The invention relates to a method for production of D- and/or L-methionine via D- and/or L-homoserine with subsequent chemical transformation to give methionine.

Abstract: A process for the preparation of ?-substituted carboxylic acids from the series including ?-hydroxycarboxylic acids and N-substituted-?-aminocarboxylic acids by cathodic carboxylation with carbon dioxide of a compound corresponding to the general formula R1—C(?X)R2 which is constituted by aldehydes, ketones or N-substituted imines. In the past, that carboxylation has taken place in an undivided electrolytic cell with the use of a sacrificial anode. As described herein, the carboxylation takes place in the absence of a sacrificial anode in an electrolytic cell divided by a separator, at a diamond film cathode. The anode is formed of a material which is stable under electrolytic conditions; in particular, it is a diamond film electrode. The catholyte includes an organic solvent and a conducting salt.

Abstract: The invention relates to a process for the preparation of methionine of high bulk density, in which a mixture which comprises a compound which has a foaming action and a compound which influences the crystallization is added to the hydrolysis solution, and to the mixture itself.