From Ionic Liquid to Electrolyte Solution: Dynamics of 1-N-Butyl-3-N-methylimidazolium Tetrafluoroborate/Dichloromethane Mixtures

Dielec. spectra have been measured at 25 °C for mixts. of the room temp. ionic liq. 1-N-butyl-3-N-methylimidazolium tetrafluoroborate (IL) with dichloromethane (DCM) over the entire compn. range at frequencies 0.2 .ltorsim. ν/GHz ≤ 89. The spectra could be satisfactorily fitted by assuming only two relaxation modes: a Cole-Cole process at lower frequencies and a Debye process at higher frequencies. However, detailed anal. indicated that both spectral features contain addnl. modes, which could not be resolved due to overlaps. The spectra indicate that the IL appears to retain its chem. character to extraordinarily high levels of diln. (xIL ⪆ 0.5) in DCM. At even higher dilns. (xIL .ltorsim. 0.3), the IL behaves as a conventional but strongly assocd. electrolyte