Heat capacities and electrical conductivities of 1-ethyl-3-methylimidazolium-based ionic liquids

We present the heat capacities and electrical conductivities of five [Emim] 1-ethyl-3-methylimidazolium-based ionic liquids: [Emim][BF4] (tetrafluoroborate), [Emim][CF3SO3] (trifluoromethanesulfonate), [Emim][C2N3] (dicyanamide), [Emim][C2H5SO4] (ethylsulfate),and [Emim][MDEGSO(4)](2-(2-methoxyethoxy) ethylsulfate), The heat capacities were measured using a differential scanning calorimeter (DSC) over the temperature ranging from (303.2 to 358.2) K. The electrical conductivities were measured over the temperature ranging from (293.2 to 353.2) K using a commercial conductivity meter. The estimated uncertainties of heat capacity C-p and electrical conductivity sigma measurements were +/- 0.015 kJ . kg(-1) . K-1 and +/- 0.001 mS . cm(-1), respectively. The measured C-p and sigma are presented as a function of temperature. The temperature dependency of the C-p value was correlated using an empirical equation. A modified version of VTF-type (Vogel-Tamman-Fulcher) equation was used to describe the temperature dependency of sigma values. The correlations give satisfactory results. Also, the results of this study are in good agreement with the available literature data. The heat capacities and electrical conductivities presented in this work are in good agreement with the available literature data. The results of this study can be applied to numerous chemical processes, since C-p and sigma data are essential information for rational design. (C) 2008 Elsevier Ltd. All rights reserved.