Thermodynamic Properties of Ternary Liquid Mixtures of 2-Pyrrolidinone with Aromatic Hydrocarbons

Molar excess volumes, V(ijk)(E), and speeds of sound, u(ijk), of 2-pyrrolidinone (2-Py) (i) + toluene (j) + o-xylene or p-xylene (k) ternary mixtures have been determined by using a dilatometer and interferometer as a function of composition at 308.15 K. The speeds of sound of ternary mixtures have been utilized to predict their excess isentropic compressibilities. The Redlich-Kister equation has been fitted to the molar excess volumes, V(ijk)(E), and excess isentropic compressibilities, (kappa(E)(S))(ijk), to predict ternary adjustable parameters and standard deviations. The observed data have been analyzed in terms of the Flory theory and the Sanchez and Lacombe theory.