| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method advantageous in cost, for efficiently carrying out the recovery of valuable components of methionine. SOLUTION: The method for producing the methionine includes the following steps (1), (2), (3) and (4): (1) a reaction step: a step of hydrolyzing 5-[2-(methylthio)ethyl]imidazolidine-2, 4-dione in the presence of a basic potassium compound; (2) a first crystallization step: a step of crystallizing the methionine by introducing carbon dioxide to the reaction liquid obtained in the step (1), and separating the obtained slurry into a precipitate and a mother liquor; (3) a second crystallization step: a step of concentrating the mother liquor obtained in the step (2), mixing the concentrated liquor with a lower alcohol, introducing the carbon dioxide to the resultant mixed liquid to crystallize the methionine and potassium hydrogen carbonate, and separating the obtained slurry into a precipitate and a mother liquor, and (4) a heating step: a step for concentrating the mother liquor obtained in the step (3), subjecting the concentrated liquor to heat treatment within the range of 150-200°C, and recycling the heat-treated product to the step (3). COPYRIGHT: (C)2010,JPO&INPIT
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