General Description
1-Butyl-3-methylimidazolium hexafluorophosphate is an imidazolium-based, hydrophobic, room temperature ionic liquid (RTIL). It can be prepared by reacting 1-methylimidazole with chlorobutane. Gaseous hydrofluorocarbons (HFCs) such as fluoromethane, fluoroethane and 1,1,2,2-tetrafluoroethane are soluble in BMIMPF6.
Synthesis
81.89 g (1.0 mol) of 1-methylimidazole, 128.95 g (1.0 mol) of and 92.0 g (1.0 mol) of potassium hexafluorophosphate in a 500 ml three-necked round bottom flask with a reflux condenser at 80 °C for 12 h. 1-bromobutane De-ionized water (100 ml) was added and a bi-phase was formed. The immiscible ionic liquid layer was separated from the water phase with a separating funnel. The ionic liquid was washed with de-ionized water (2 × 50 ml) until the water phase did not react with 0.001 M aqueous silver nitrate (AgNO3). Diethyl ether(2 × 30ml) was added to the ionic liquid and separated in a separating funnel. The ionic liquid 1-Butyl-3-methylimidazolium hexafluorophosphate was dried in a vacuum for 2 h. A colourless liquid was obtained Yield (86 per cent). 1H NMRof the ionic liquid sample (300MHz, DMSO) contains peaks at δ: 9.05 (s, 1H-imidazole), 7.77 (s, 1H-imidazole), 7.65 (s, 1H-imidazole),4.16 (s, N–CH3), 3.8 (s, N–methyl), 1.8 (s, CH2), 1.30 (s, CH2), and 0.92(t, methyl).
