Ionic Liquid Catalysis

Ionic liquids have undergone extensive research as solvents in the majority of catalytic reactions. 1–4 Their advantage is that their physical-chemical properties can be easily adjusted by changing the anion, the cation, or its substitution pattern. Using this method, an ionic liquid can be created that has the ideal characteristics (viscosity, solubility of substrates and products, etc.) for a particular application. 5 By making a homogeneous reaction mixture bi-phasic in catalysis, this property can be advantageously exploited, combining the benefits of homogeneous and heterogeneous catalysis. The removal of products using heat is an alternative to phase separation; the solvent and catalyst can be quantitatively retained during distillation processes due to the negligibly low vapour pressure of ionic liquids. Liquid Ions Additionally, the use of ionic liquids as biocatalytic solvents has been investigated. For instance, in the lipase-catalyzed trans-esterification of various substrates4,9–11 in ionic liquids based on the 1-alkyl-3-methylimidazolium or 4-methyl-N-alkylpyridinium cation and anions like tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, etc., high enantiomeric excesses The selectivity of a biocatalytic reaction was altered as a result of interactions between the Ionic Liquid and the enzyme, which led to this discovery. After the products from the Ionic Liquid phase were extracted with diethyl ether, the Ionic Liquid and enzyme were both recyclable