Determination and modeling of activity coefficients of the ionic liquid 1-ethyl-3-methylimidazolium chloride in the (water + formamide) mixed solvent system at 298.2 K

Abstract

In this work, the results relating to the mean activity coefficient measurements for 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) in the (formamide+water) mixed solvent system using the potentiometric method have been reported. The electromotive force (emf) measurements were performed on the galvanic cell of the type: Ag|AgCl|[EMIm]Cl (m), formamide (wt.%), H2O (1−wt) %|EMIm-ISE, in various mixed solvent systems containing 0, 10, 20, 30, and 40% mass fractions of formamide over ionic strength ranging from 0.0010 to 2.5000mol·kg−1 at T=298.2K. The modeling of this ternary system was made based on the Pitzer ion-interaction model. The values of the mean activity coefficients, the osmotic coefficients, the excess Gibbs free energy and the solvent activity together with Pitzer ion-interaction parameters (β(0), β(1) and Cϕ) for the series under investigated system were determined.