The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 11, 2016
Filed:
Sep. 10, 2015
Martin Koerfer, Kahl, DE;
Hans Joachim Hasselbach, Gelnhausen, DE;
Stefan Reichert, Frankfurt, DE;
Harald Jakob, Hasselroth, DE;
Christoph Weckbecker, Gruendau, DE;
Klaus Huthmacher, Gelnhausen, DE;
Horst Krull, Hanau, DE;
Bernd Drapal, Alzenau, DE;
Rainer Peter, Krombach, DE;
Martin Koerfer, Kahl, DE;
Hans Joachim Hasselbach, Gelnhausen, DE;
Stefan Reichert, Frankfurt, DE;
Harald Jakob, Hasselroth, DE;
Christoph Weckbecker, Gruendau, DE;
Klaus Huthmacher, Gelnhausen, DE;
Horst Krull, Hanau, DE;
Bernd Drapal, Alzenau, DE;
Rainer Peter, Krombach, DE;
EVONIK DEGUSSA GmbH, Essen, DE;
Abstract
This disclosure relates to a process for preparing D,L-methionine by feeding carbon dioxide 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. In this process an aqueous solution of the separated-off crude methionine is purified by recrystallization from a solution containing potassium ions and also a crystallization additive. The crystallization additive is a nonionic or anionic surfactant, or a mixture of different nonionic or anionic surfactants. The recrystallization occurs by introducing a 60 to 110° C.-hot methionine solution into a 35 to 80° C.-warm methionine suspension, a temperature of which is lower than that of the introduced solution, such that the temperature of the methionine suspension being maintained between 35 and 80° C. during the addition. The crystallization additive is a sorbitan fatty acid ester or a mixture of different sorbitan fatty acid esters.