Document Type : Regular Article
Department of Chemistry, Faculty of Science, University of Guilan, P. O. Box: 19141, Rasht, Iran
In this work, the results relating to the mean activity coefficient measurements for ionic liquid of 1- propyl -3 methylimidazolium bromide, [PMIm]Br in ethanol+ water mixtures have been reported using potentiometric measurements at T=( 298.2, 308.2 and 318.2)K. The electromotive force (emf) measurements were performed on the galvanic cell of the type:Br-ISE│[PrMIm] (m) ethanol (wt.%), H2O (1−wt) %│ [PrMIm] -ISE, in mixed solvent system containing 0, 10, 20, 30% mass fractions of ethanol over ionic strength ranging from 0.0010 to 2.0000 mol•kg−1. The Pitzer ion-interaction model was used to analyze the activity coefficients for studied system. The Pitzer ion-interaction parameters (β(0), β(1) and Cϕ) were determined and employed to calculate the mean activity coefficients, the osmotic coefficients and excess Gibbs free energies for the whole series the studied system.