Ionic liquids as media for electro-organic synthesis

The IL’s used in this study were either synthesized or commercially available. Preparation of the IL’s involved 2 step processes: firstly the heating of distilled 1-methylimidazole with distilled 1-chlorobutane under reflux to obtain 1-butyl-3- methylimidazolium chloride; secondly, the metathesis reaction of sodium tetrafluoroborate with 1-butyl-3-methylimidazolium chloride to obtain 1-butyl-3- methylimidazolium tetrafluoroborate. The addition of sodium tetrafluoroborate, sodium hexafluorophosphate and lithium trifluoromethane sulfonamide with 1-butyl-3-methylimidazolium chloride produced good yields of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide respectively. The IL’s are hygroscopic and must be stored under a nitrogen atmosphere. The IL’s were analyzed using 1H and 13C NMR analysis with CDCl3 as solvent. The physical and chemical properties of these IL’s were compared to commercial products. The physical and chemical properties compared well to reference values from the literature. The physical properties measured include the density, conductivity and electrochemical window. The electrochemical window is dependant primarily on the resistance of the cation to reduction and the resistance of the anion to oxidation. The electrochemical windows of the IL’s were very similar to the reference windows obtained from literature and it can be seen that some IL’s have a slightly lower window which can be due to water present. Water content in the IL’s was determined with the use of a Karl Fischer titrator, with Hydranal 5 Composite as titrant and HPLC grade methanol as the base. The concentration of halide in the IL’s was determined with a Perkin-Elmer ICP-MS