In recent years ambient-temperature ionic liquids have
been studied extensively for both catalytic and electrochemical
applications.1-3 They are of interest because they have
negligible vapor pressure, large liquid temperature ranges,
wide potential windows, and high ionic conductivities, and
in some cases they are Lewis acid catalysts. Early investigations
focused on imidazolium or pyridinium cations with
chloroaluminate anions although increasing amounts of work
have been carried out using inert anions such as BF4
- and
PF6
-. Osteryoung4 showed that n-butylpyridinium salts gave
liquids over a wide range of composition with AlCl3, and
similar results were found using n-alkylimidazolium chloroaluminate
melts.5 The chemistry of these ionic liquids is
controlled by the chloroaluminate anions; the relative proportions
of each anion change considerably with melt composition.
6 These melts have been used for metal deposition, for
aluminum batteries, and as media in which to carry out a
variety of reaction