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Dynamic viscosity and specific electrical conductivity on three binary systems of 1-alkyl-3-methyl imidazolium tetrafluoroborate [CnMIM][BF 4 ] with water covering all ranges of concentrations are presented. Viscosity was measured at 15.0 °C, 25.0 °C, 35.0 °C, and 45.0 °C, while conductivity was measured at those four temperatures for equimolar mixtures only and at 25 °C over the whole composition range. The alkyl chains of the ILs used were ethyl [EMIM][BF 4 ], butyl [BMIM][BF 4 ], and hexyl [HMIM][BF 4 ]. Note that [HMIM][BF 4 ] is only partially miscible in water at the studied temperatures and atmospheric pressure.Viscosity deviations and molar conductivity were derived from experimental data and fitted to suitable equations. Experimental data were also compared with those previously published, and a good agreement was observed. Transport properties were discussed in terms of Walden's rule, which is partially correct. This paper complements one recently published by us, where density and surface tension at 25 °C for exactly the same systems are presented. The goal of this work is to study the effect on the transport magnitudes of the alkyl chain length in the n-alkyl methyl imidazolium cation and to compare the two main transport magnitudes.

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We present experimental measurements of specific electrical (or ionic) conductivity of seven binary systems of 1-ethyl-3-methyl imidazolium alkyl sulfate (EMIM-C(n)S) with water or ethanol. Electrical conductivity was measured at 298.15 K in all ranges of concentrations and selected mixtures also at 288.15, 308.15, and 318.15 K. The alkyl chains of the anions used are ethyl (EMIM-ES), butyl (EMIM-BS), hexyl (EMIM-HS), and, only for mixtures with ethanol, octyl (EMIM-OS). Let us note that the four ionic liquids (ILs) measured are miscible in water and ethanol at those temperatures and atmospheric pressure in all ranges of concentrations, but EMIM-OS jellifies for a given range of concentration with water. We compare the measured data in terms of the alkyl chain length and solvent nature. Data are compared with previously scarce results for these same systems and also for other aqueous and ethanol mixtures with ILs. In addition, we verify that our data fit the universal theoretical expression with no fitting parameters given by the pseudolattice-based Bahe-Varela model, except for IL concentrated mixtures. To fit well all ranges of concentrations, we add to the original equation two phenomenological terms with one fitting parameter each. Finally, we calculate the molar conductivity and fit it successfully with an expression derived from Onsager theory.