Chiral purification by enantioselective extraction: Principles and recent development

Due to its crucial importance in many industries, such as food, agrochemicals, and pharmaceuticals, chirality has gained increasing attention in recent decades. To address the need for a pure enantiomer, several methods have been developed such as crystallization, chromatographic approaches, kinetic resolution enzymatic methods, microbiological methods, and extraction. This review provides an overview of enantioselective extraction methods as being flexible, cost-effective, and suitable for large-scale production. Solid-liquid extraction (SLE) and liquid-liquid extraction (LLE) are the most used chiral extraction methods, showing significant benefits and leading to the widespread application of the method at large scale for industrial purposes. Several novel methods have been developed over the last few years to perform LLE and SLE, however, the traditional methods are still widely utilized. Throughout the paper monophasic recognition chiral extraction, biphasic recognition chiral extraction, and multi-stage LLE techniques, as well as the magnetic, molecularly imprinted polymer, metal-organic frameworks-based SLE methods are discussed as the most frequently used methods in the context of both benefits and limitations. Although there have been several publications on enantioselective LLE and SLE, no comprehensive review has been reported during the past few years. In this study, different categories and applications of both techniques have been considered.