The process of separation of a racemic mixture into the enantiomers.
Chemical method (salt formation method):
Consider a racemic mixture of enantiomeric organic acid (I) – HA. It can be separated into pure enantiomeric acid by reaction with an optically active base, say a laevorotatory base (-) – B. The mixture of enantiomeric acids on reaction with an optically active base result in the formation of two diastereomeric salts as shown in the figure. These diastereomeric salts have, of course, different physical properties, including solubility in a given solvent. They can, therefore, be separated, by a simple technique i.e., fractional crystallization.
