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Conductometric properties of selected ionic liquids in ethylene glycol in the temperature range T = (278.15 - 313.15) K

Conductometric measurements of the investigated ionic liquids: 1-methylimidazolium chloride, 1, 3- dimethylimidazolium chloride, 1-ethyl-3- methylimidazolium chloride, and 1-butyl-3- methylimidazolium chloride in ethylene glycol were carried out in a wide range of temperatures T = (278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K and in the concentration range from about 0.0002 mol dm-3 to about 0.017 mol dm-3. Conductometric measurements made it possible to determine the values of limiting molar conductances and using a chemical model of low concentration (lcCM) the values of the association constants of the studied ionic liquids. Using the temperature values of limiting molar conductivity the value of Eyring activation enthalpy of charge transfer was determined. The values of thermodynamic functions of ion pair formation (such as Gibbs energy, entropy and enthalpy) and the values of the diffusion coefficient were also determined and discussed. The obtained results are the first data in the literature that allow the assessment of the influence of the physicochemical properties and the internal structure of the solvent on the conductivity values and the determined thermodynamic functions of the studied ionic liquids.

ionic liquids ; ethylene glycol ; conductometry

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