Abstract
Molar conductivities, Λ, of dil. solns. of the ionic liq. 1-ethyl-3-methylimidazolium ethylsulfate in water, acetonitrile (AN), and dichloromethane (DCM) were detd. as a function of temp. (AN: T = (273.15 to 313.15) K; DCM: T = (273.15 to 308.15) K; water: T = (278.15 to 313.15) K) in the concn. range c = (≈ 0.25 to ≈ 5) × 10-3 mol/dm-3. The data were analyzed with Barthel's low-concn. chem. ...
Abstract
Molar conductivities, Λ, of dil. solns. of the ionic liq. 1-ethyl-3-methylimidazolium ethylsulfate in water, acetonitrile (AN), and dichloromethane (DCM) were detd. as a function of temp. (AN: T = (273.15 to 313.15) K; DCM: T = (273.15 to 308.15) K; water: T = (278.15 to 313.15) K) in the concn. range c = (≈ 0.25 to ≈ 5) × 10-3 mol/dm-3. The data were analyzed with Barthel's low-concn. chem. (lcCM) model to obtain the limiting molar conductivities, Λ∞(T), and assocn. consts., KA°(T), of this electrolyte in the investigated solvents. From Λ∞(T) the Eyring activation enthalpy of charge transport was detd. and found to be slightly larger than the corresponding value for viscous flow of the solvent. Strong ion pairing was found for the electrolyte in DCM (KA° ≈ 6/104 mol-1/dm3), whereas ion assocn. in AN is rather weak (KA° ≈ 40 mol-1/dm3). From the temp. dependence of KA°(T) the enthalpy and entropy of the ion-pairing process were calcd., and ion assocn. was found to be entropy-driven for both nonaq. solvents. In water the salt is fully dissocd.
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