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:
Nov. 05, 1985
Filed:
Mar. 21, 1983
Degussa Aktiengesellschaft, Frankfurt, DE;
Abstract
The subject matter of the invention is a process for the recovery of S-(carboxymethyl)-(R)-cysteine and S-(carboxymethyl)-(S)-cysteine from a mixture of the two enantiomers. The mixture to be separated is dissolved in water in the presence of sufficient ammonia that the ammonium salt solution formed has a pH between 6 and 9. Then there is brought about in the solution of ammonium salt a state of supersaturation by the addition of seeding crystals of the ammonium salt of one of the two enantiomers, insofar as the starting material contains one of the two enantiomers in excess, the ammonium salt of this enantiomer, the ammonium salt of one of the two enantiomers is brought to crystallization and separated off. Subsequently by addition of seeding crystals of the ammonium salt of the other enantiomers to the remaining mother liquor the ammonium salt of this enantiomer is likewise brought to crystallization and separated off. Finally the respective S-(carboxymethyl)-cysteine is set free from the two ammonium salts.