Selection of Ionic Liquid Solvents for Chemical Separations Based on the Abraham Model [chapter]

William E., Jr., Laura M., Michael H.
2011 Ionic Liquids: Applications and Perspectives  
Introduction Room temperature ionic liquids (RTILs) have generated considerable interest in the past decade because of their unique physical and chemical properties. Each year the number of published applications employing RTILs as solvent media has increased. New generation RTILs are a popular solvent choice for manufacturing applications involving nano-materials and new pharmaceutical drug molecules, as high-temperature lubricants for metal-to-metal contacts, as reservoirs for the controlled
more » ... for the controlled release of drug molecules in pharmaceutical formulations, as chromatographic stationary phases for gas chromatographic separations, as gas absorption agents, and as an extraction solvent system for the removal of aromatic nitrogen and sulfur compounds from coal and petroleum feedstocks. RTILs are usually made by combining a poorly coordinating cation and anion to give a highly polar ionic liquid. Ionic liquids are often immiscible with supercritical carbon dioxide, saturated linear hydrocarbons and several acyclic organic solvents. Liquid immiscibility makes RTILs ideally suited for synthetic methods involving biphasic catalysis. Currently synthetic procedures are available for preparing more than 300 different ionic liquids (ILs), including dication and tricationic bis/tris-imidazolium-based ILs, polymeric ionic liquids (PILs), and chirial ionic liquids. Methods have also been developed for introducing polar functional groups to the end of an alkyl CH 2 -chain. The overall physical and solubilizing properties of ILs result from the composite properties of the cation and anion. The anion generally controls the extent to which the RTIL is miscible with water.
doi:10.5772/14518 fatcat:l4jzeifv4jgonpbd5smn63hzcy