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 deg C.Most common RTILs are composed of unsymmetrically substituted nitrogen-containing cations(e.g.,imidazole,pyrrolidine,pyridine)with inorganic anions(e.g.,Cl~-,PF_6~-,BF_4~-).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.
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