Room-Temperature Ionic Liquids: Solvents for Synthesis and Catalysis. 2

A scientific review focuses on the use of room-temperature ionic liquids (IL) as solvents in synthesis and catalysis. The review concentrates on those studies that have sought to understand how ionic liquids can affect the reactivity of solute materials. A number of such room-temperature ionic liquids have bee prepared over a period of time to be used as solvents in synthesis and catalysis. The vast majority of these ionic liquid cations are based upon alkylated amines, with a smaller number of phosphonium and sulfonium salts used. It has also been demonstrated that the IL can be prepared by metathesis of the halide salt with a metal or ammonium salt or the conjugate acid of the required anion. This can be done in aqueous solution for hydrophobic ionic liquids with the product separating during the reaction. The aqueous solution can be washed with CH2Cl2 and the ionic liquid isolated from the CH 2Cl2 solution to increase the overall yield.