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:
Sep. 05, 2000
Filed:
Jun. 16, 1998
Karlheinz Drauz, Freigericht, DE;
Andreas Bommarius, Frankfurt, DE;
Michael Karrenbauer, Moss-Bankholzen, DE;
Gunter Knaup, Bruchkobel, DE;
Degussa Aktiengesellschaft, Frankfurt, DE;
Abstract
The disclosure relates to a process for obtaining optically active L-.alpha.-aminocarboxylic acids from the corresponding racemic D,L,.alpha.-aminocarboxylic acids. The following steps are involved: (a) the D,L,.alpha.-aminocarboxylic acids are acetylated; (b) the N-acetyl-L-.alpha.-aminocarboxylic acid present in the mixture of N-acetyl-D,L,.alpha.-aminocarboxylic acids thus obtained is broken down enzymatically into the L-.alpha.-aminocarboxylic acid; (c) the L-.alpha.-aminocarboxylic acid is separated from the mixture, a quantity of a solution of N-acetyl-D(L)-.alpha.-aminocarboxylic acids and a quantity of acetate equivalent to the L-.alpha.-aminocarboxylic acid being retained; and (d) the N-acetyl-D(L)-.alpha.-aminocarboxylic acid is racemized and recycled for enzymatic breakdown. Known extraction processes involving steps (a) to (d) have the disadvantage of producing large quantities of salt. Specifically, the processes are far removed from the ideal equation, according to which one hundred percent of the acetic anhydride and the D,L,.alpha.-aminocarboxylic acids are converted to L-.alpha.-aminocarboxylic acids and acetic acid. Adjusting the retained solution from step (c) in such a way as to obtain a solution consisting essentially of N-acetyl-D-(L)-.alpha.-aminocarboxylic acid salt and free acetic acid in equilibrium with acetate and free N-acetyl-D(L)-.alpha.-aminocarboxylic acid and from which acetic acid is extracted by distillation makes it surprisingly easy to feed the solution formed as 'mother liquor' following separation of the L-.alpha.-aminocarboxylic acid in the circuit and to achieve a materials balance as close as possible to the ideal.