Preparative-scale separation of enantiomers of chiral carboxylic acids

A process for recovering a selected enantiomer from a mixture of first and second enantiomers of a chiral carboxylic acid selected from the group consisting of flurbiprofen, ibuprofen, and naproxen, said method comprising:

• (a) preparing a feed solution of solutes dissolved in a hydrophobic alkane having a boiling point between 50° C. and 150° C., said solutes comprising said first and second enantiomers, an organic acid selected from the group consisting of C1-C4 alkyl carboxylic acids and halogen-substituted C1-C4 alkyl carboxylic acids, and a tertiary alcohol;
• (b) passing said feed solution through a chromatographic separation system to achieve an extract and a raffinate as separate product solutions, said raffinate having dissolved therein said first enantiomer to the substantial exclusion of said second enantiomer, and said extract having dissolved therein said second enantiomer to the substantial exclusion of said first enantiomer;
• and
• (c) collecting said product solution containing said selected enantiomer, concentrating said collected product solution by evaporation of said hydrocarbon solvent to form a concentrated product, and storing said concentrated product for at least one hour.