Chiral Ionic Liquids and Chromatography: Synergistic Effects in Enantioseparations

Abstract

Chiral ionic liquids (CILs) are a subcategory of ionic liquids that possess a chiral moiety. The need for chiral separations in several industries, including pharmaceutical, food, and chemical industries, has led to an increasing search for materials capable of performing such separations. CILs have emerged as effective candidates for the separation of enantiomers because of their advantageous properties like low melting point, little vapor pressure, high thermal stability, good electrical conductivity, and low cost. They are being employed in chromatographic methods as chiral ligands, stationary phases, and chiral selectors for the separation of chiral compounds. As compared to other chiral selectors (cyclodextrins, polysaccharides, surfactants, and crown ethers), CILs show better solubility, easy synthesis, and low cost. They represent an intriguing opportunity for use in chromatography because of their wide range of solubility in organic and inorganic solvents, as well as their miscibility with common solvents (methanol and acetonitrile). Considering the flourishing research in the field, the present chapter summarizes the advancement in the application of CILs as chiral ligands, stationary phases, and chiral selectors in liquid and gas chromatographic techniques. Furthermore, the chiral recognition mechanism and prospects for the use of CILs in enantioseparations have been examined.