Molar Conductivities and Association Constants of 1-Butyl-3-methylimidazolium Chloride and 1-Butyl-3-methylimidazolium Tetrafluoroborate in Methanol and DMSO

Molar conductivities, Λ, of dilute solutions of the ionic liquids 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium tetrafluoroborate in methanol and DMSO were determined as a function of temperature (methanol, T = (273.15 to 313.15) K; DMSO, T = (293.15 to 318.15) K). The data were analyzed with Barthel’s low-concentration chemical model (lcCM) model to obtain the limiting molar conductivities, Λ∞(T), and association constants, KA°(T), of these electrolytes. From Λ∞(T), the Eyring activation enthalpy of charge transport and (where possible) the ion conductivity of the cation, λ∞([bmim]+), were determined.