PROCESS FOR THE PREPARATION OF METHIONINE

The invention relates to a process for the preparation of D,L-methionine, in which carbon dioxide is fed to an aqueous potassium methioninate solution obtained by hydrolysis of 5-(2-methylmercaptoethyl)hydantoin, in order to precipitate out crude methionine, which is separated off and purified, wher...

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Bibliographische Detailangaben
Hauptverfasser: KRULL, HORST, REICHERT, STEFAN, KÖRFER, MARTIN, PETER, RAINER, HASSELBACH, HANS JOACHIM, DRAPAL, BERND, JAKOB, HARALD, WECKBECKER, CHRISTOPH, HUTHMACHER, KLAUS
Format: Patent
Sprache:eng
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Zusammenfassung:The invention relates to a process for the preparation of D,L-methionine, in which carbon dioxide is fed to an aqueous potassium methioninate solution obtained by hydrolysis of 5-(2-methylmercaptoethyl)hydantoin, in order to precipitate out crude methionine, which is separated off and purified, where, for the purposes of purification, an aqueous solution of the separated-off crude methionine is prepared and subjected to a recrystallization, characterized in that the solution from which the recrystallization takes place contains potassium ions and also a crystallization additive, where the crystallization additive is a nonionic or anionic surfactant, or a mixture of different nonionic or anionic surfactants, and that the recrystallization takes place by introducing a 60 to 110°C-hot methionine solution into a 35 to 80°C- warm methionine suspension, the temperature of which is lower than that of the introduced solution, the temperature of the: methionine suspension being maintained between 35 and 80°C during the addition.