Molar heat capacity and electrolytic conductivity of aqueous solutions of [Bmim][MeSO4] and [Bmim][triflate]

Here we report the new measurements of molar heat capacity, C-P and electrolytic conductivity, sigma for aqueous solutions of 1-butyl-3-methylimidazolium methylsulfate, [Bmim][MeSO4] and 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [Bmim][triflate]. Heat capacities were measured from 303.2 to 353.2 K with a differential scanning calorimeter. Electrolytic conductivities were measured from 293.2 to 353.2 K with a commercial conductivity meter. The estimated uncertainties of C-P and sigma measurements were +/-2 and +/-1%, respectively. The present measurements of C-P and sigma were presented as a function of temperature and composition. An excess molar heat capacity C-P(E) expression using the Redlich-Kister equation for the temperature and composition dependence was used to represent the measured C-P and a modified empirical equation was used to correlate the temperature and composition dependence of the measured sigma of the studied systems. The applied correlations represent the C-P and sigma measurements satisfactorily. The C-P and sigma values presented in this work are, in general, of sufficient accuracy for most engineering-design calculations. (C) 2009 Elsevier B.V. All rights reserved.