Conductometric Studies of 1-Ethyl-3-methylimidazolium Tetrafluoroborate and 1-Butyl-3-methylimidazolium Tetrafluoroborate in 1-Propanol at Temperatures from (283.15 to 318.15) K

Abstract

The electrical conductances of dilute solutions of the ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate [emim][BF4] and 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4] in 1-propanol have been measured in the temperature range from (283.15 to 308.15) K at 5 K intervals. The ionic association constant, KA, limiting molar conductances, Λo, and distance parameters, R, were obtained using the low concentration Chemical Model (lcCM). The examined electrolytes are strongly associated in 1-propanol in the whole temperature range. From the temperature dependence of the limiting molar conductivities the Eyring’s activation enthalpy of charge transport was estimated. The thermodynamic functions such as Gibbs energy, entropy, and enthalpy of the process of ion pair formation were calculated from the temperature dependence of the association constants.