Effect of co-solvent and temperature on interactions in 1-ethyl-3-methylimidazolium trifluoromethanesulfonate plus ethylene glycol or/and N,N-dimethylformamide, and ethylene glycol plus N,N-dimethylformamide mixtures: Measurement of thermophysical properties

The excess molar volumes, V-E, excess molar isentropic compressibilities, K-s,m(E), viscosity deviations, Delta eta and Gibbs free energies of activation, Delta G(center dot) have been determined by using the experimentally measured values of densities, rho, speeds of sound, u, and viscosities, eta of pure 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM] [CF3SO3]), ethylene glycol (EG) and N,N-dimethylformamide (DMF) and of binary mixtures [EMIM][CF(3)SO3] + EG/DMF; EG + DMF in the mole fraction range (chi(1)) from 0 to 1 and of ternary mixture [EMIM][CF3SO3] + DMF + EG in the range of chi(1) from 0.03 to 0.8 at temperatures, (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K and pressure 0.1 MPa. The V-E, K-s,m(E) and Delta eta values of binary systems have been correlated with Redlich-Kister polynomial equation. The VE, K-s,m(E) and Delta eta values of ternary system have been correlated with Cibulka equation. The variations of measured data with composition and temperature are discussed in terms of ion-ion, ion-dipole and dipole-dipole interactions prevailing in the mixtures. We have also applied a number of semiempirical relations for correlation/prediction of our experimental dynamic viscosity data and evaluated some interactional parameters of studied binary mixtures. The excess molar volumes of each binary system have also been correlated to the Prigogine-Flory-Patterson (PFP) theory. (C) 2018 Elsevier B.V. All rights reserved.