Ionic liquid extraction systems utilizing ion recognition

Abstract

Ionic liquids have attracted much attention as the third liquid because they possess different properties from those of water and organic solvents. Their unique properties have encouraged us to develop liquid-liquid extraction systems using ionic liquids as extracting media. In this review, we describe metal ion and protein extractions in ionic liquid-water biphasic systems using the size recognition ability of macrocyclic compounds. Furthermore, we report the potential utility of ionic liquids as novel reaction media for biological catalysis with proteins extracted.