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Ionic Liquids In Analytical Chemistry, Jared L. Anderson, Daniel W. Armstrong, Guor-Tzo Wei

Jared L. Anderson

Room-temperature ionic liquids (RTILs), also known as liquid organic, molten, or fused salts, are a class of nonmolecular ionic solvents with low melting points. The accepted definition of an RTIL is any salt that has a melting point lower than ambient temperature (1). However, “ionic liquid” (IL) is often applied to any compound that has a melting point <100 °C. Most common RTILs are composed of unsymmetrically substituted nitrogen-containing cations (e.g., imidazole, pyrrolidine, pyridine) with inorganic anions (e.g., Cl–, PF6 –, BF4 –). ILs are also interesting because of their other useful and intriguing physicochemical properties. Wilkes et al. first reported ambient-temperature ILs based on the 1-alkyl-3-methylimidazolium cation in 1982 (2). Since then, many ILs containing a variety of cations and anions of different sizes have been synthesized to provide specific characteristics.