ABSTRACT

Temperature-dependent conductivity, viscosity, and density of four ionic liquids (ILs), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIM][NTf2]), and 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]), were measured with high precision from +80 deg C down to -35 deg C, if possible. Fitting parameters for the Vogel-Fulcher-Tammann (VFT) equation were obtained for conductivity and viscosity data, and obtained data were analyzed with the help of the fractional Walden rule and the Walden plot. Excellent linear behavior is observed for all ILs; however, the average slope is not unity as expected for the ideal Walden rule, but 0.92 +- 0.02. The so-called ideal KCl line that is used to compare ILs within the Walden plot is discussed, as literature data for aqueous KCl solutions show that its assumed ideality has to be modified.

Compounds

#	Formula	Name
1	C6H11BF4N2	1-ethyl-3-methylimidazolium tetrafluoroborate
2	C8H15BF4N2	1-butyl-3-methylimidazolium tetrafluoroborate
3	C8H11F6N3O4S2	1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide
4	C8H11N5	1-ethyl-3-methylimidazolium dicyanamide

Datasets

The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type	Compound-#	Property	Variable	Constraint	Phase	Method	#Points
POMD	1	Electrical conductivity, S/m ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Symmetrical Wheatstone bridge	13
POMD	1	Viscosity, Pa*s ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Capillary tube (Ostwald; Ubbelohde) method	12
POMD	1	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	5
POMD	2	Electrical conductivity, S/m ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Symmetrical Wheatstone bridge	11
POMD	2	Viscosity, Pa*s ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Capillary tube (Ostwald; Ubbelohde) method	8
POMD	2	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	5
POMD	3	Electrical conductivity, S/m ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Symmetrical Wheatstone bridge	12
POMD	3	Viscosity, Pa*s ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Capillary tube (Ostwald; Ubbelohde) method	12
POMD	3	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	5
POMD	4	Electrical conductivity, S/m ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Symmetrical Wheatstone bridge	13
POMD	4	Viscosity, Pa*s ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Capillary tube (Ostwald; Ubbelohde) method	14
POMD	4	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	5

Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

Fractional Walden Rule for Ionic Liquids: Examples from Recent Measurements and a Critique of the So-Called Ideal KCl Line for the Walden Plot

Schreiner, C.[Christian], Zugmann, S.[Sandra], Hartl, R.[Robert], Gores, H. J.[Heiner J.]

ABSTRACT