| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method improving the recovering amount in secondary crystallization.SOLUTION: This method for producing the methionine is provided by comprising the following processes (1) to (3): (1) a reaction process of hydrolyzing 5-[2-(methylthio)ethyl]imidazolidine-2,4-dione in the presence of a basic potassium compound, (2) a first crystallization process of introducing carbon dioxide into the reaction liquid obtained from the process (1) to precipitate the methionine and separating the obtained slurry into the precipitate and mother liquor, and (3) a second crystallization process of adding the basic potassium compound to the mother liquor obtained in the process (2), heat-treating, then introducing carbon dioxide to precipitate the methionine and potassium hydrogen carbonate and separating the obtained slurry into the precipitate and mother liquor. |
