Enantiomer enrichment by solvent extraction: A novel separation technique for some chiral compounds

ORGN 568

S. Alex Studniarz, sas33@psu.edu, Chemistry, Penn State University, 146 Shenango Ave, Sharon, PA 16146
There is a substantial interest in obtaining enantiopure compounds as, for example, in pharmaceutical medicines. A new technique is described that greatly enriches the enantiomer in solution based on solvent extraction. Although the physical properties, e.g. such as boiling points, melting points, densities, and solubilities, of the pure d and the l enantiomers are identical, the physical properties of the solid (or liquid) racemate are different then those of the enantiomers. It will be shown that the observed ratio of solubility for enantiomer to racemate depends on the enthalpy difference between the solid enantiomers and solid racemate produced largely by differences in the molecular asymmetry and also on the activity coefficient of the dissolved enantiomers. For strongly hydrogen bonded solids the enthalpy difference can be large enough to produce a factor of 5 differences in solubility, e.g., tartaric acid, thus permitting the large enrichment of the excess enantiomer by solvent extraction. Enrichment of greater than 90% of the enantiomer was obtained for tartaric acid. The theory, calculations and laboratory data will be given for tartaric acid.


Asymmetric Reactions, Heterocycles, Aromatics, Combinatorial, and Physical Organic Chemistry
8:00 PM-10:00 PM, Wednesday, 31 August 2005 Washington DC Convention Center -- Hall A, Poster

8:00 PM-10:00 PM, Monday, 29 August 2005 Washington DC Convention Center -- Hall A, Sci-Mix

Division of Organic Chemistry

The 230th ACS National Meeting, in Washington, DC, Aug 28-Sept 1, 2005