Journal of Chemical and Engineering Data, Vol.61, No.11, 3788-3793, 2016
Conductance and Ionic Association of Imidazolium-Based Ionic Liquids in N,N-Dimethylacetamide
The electrical conductivity of dilute solutions of the ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate [emim] [BF4] and 1-butyl-3-methylimidazolium tetrafluoroborate [bmim] [BF4] in N,N-dimethylacetamide (DMA) have been measured over the temperature range from (283.15 to 318.15) K. The conductance data was analyzed using the low concentration Chemical Model (lcCM) in terms of the ionic association constant, K-A, the limiting molar conductivities, Lambda(o), and distance parameters, R. Slight ionic association was found for the ionic liquids in DMA within the investigated temperature range. From the temperature dependence of the limiting molar conductivities the Eyring activation enthalpy of charge transport was designated. The thermodynamic parameters such as Gibbs free energy, entropy, and enthalpy for the process of ion pair formation were estimated from the ion association constants at various temperatures. The obtained results were compared with those in N,N-dimethylformamide.