Separation of pure optical stereoisomers by pressure crystallization
US5019658A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 23, 1989 |
| Grant date | May 28, 1991 |
| Priority date | — |
| Expiry date | Oct 23, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C2601/14
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The instant invention is an improvement in the method of producing optically pure sterioisomers from a racemic mixture. The method is based on the well-known fact that a supersaturated solution or melt of the racemic mixture can be seeded with just the crystals of the desired stereoisomer, which will then crystallize out selectively, leaving the undesired stereoisomer behind in the liquid mother liquor. The desired isomer, in crystaline form, can then be separated by simple liquid/solid separation from the undesired isomer remaining behind in the mother liquor. In the conventional method, supersaturation is achieved by careful cooling of a saturated solution or melt. In the present invention, supersaturation is achieved by increasing the ambient pressure over the saturated solution or melt of the racemic mixture, and relying on the fact that the melting temperature of a substance increases with increasing pressure, provided there is an increase in molar volume when the substance melts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.