Synthesis of High-Purity Imidazolium Tetrafluoroborates and Bis(oxalato)borates.

The synthesis and purification of imidazolium-based ionic liquids (ILs) with boron-containing anions is reported. The scope was the optimization of the meta thesis reaction and on the purification of the synthesized ILs. It was possible to reduce the reaction and purification times, to avoid the use of acetonitrile as processing solvent, and to increase the yield compared to the known procedure for [BOB]- anion-containing ILs. Furthermore, to the best of our knowledge the flashpoints of the ILs could be determined for the first time by the continuously closed-cup flashpoint (CCCFP) method.