From ionic liquid to electrolyte solution: Dynamics of 1-n-butyl-3-N- methylimidazolium tetrafluoroborate/ dichloromethane mixtures

Hunger, J., Stoppa, A., Buchner, R. and Hefter, G. (2008) From ionic liquid to electrolyte solution: Dynamics of 1-n-butyl-3-N- methylimidazolium tetrafluoroborate/ dichloromethane mixtures. Journal of Physical Chemistry B, 112 (41). pp. 12913-12919.

Abstract

Dielectric spectra have been measured at 25°C for mixtures of the room temperature ionic liquid 1-N-butyl-3-W-methylimidazolium tetrafluoroborate (IL) with dichloromethane (DCM) over the entire composition range at frequencies 0.2 ≲ v/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 analysis indicated that both spectral features contain additional modes, which could not be resolved due to overlaps. The spectra indicate that the IL appears to retain its chemical character to extraordinarily high levels of dilution (xIL ≳ 0.5) in DCM. At even higher dilutions (xIL ≲ 0.3), the IL behaves as a conventional but strongly associated electrolyte.