Thermodynamics of mixtures containing alkoxyethanols Part XXVII. Predictions on isobaric thermal expansion coefficients, compressibilities and speeds of sound from the Flory theory

The Flory model is applied to predict the isobaric expansion coefficients, alpha(p), isentropiC, kappa(S), and isothermal, kappa(T), compressibilities and speeds of sound, u, of the highly complex mixtures: hydroxyether + alkane, + dibutylether, + 1-butanol or + 2-methoxyethanol, 1-alkanol + alkane, and 1-alkanol + dibutylether. Predictions were obtained using the energetic parameter, chi(12), determined from values of excess enthalpies, H-E and from values of the excess isochoric internal energies, U-V(E), at equimolar composition. No meaningful differences exist between such predictions. Deviations between experimental and calculated values are lower than 2% for mixtures containing alkoxyethanols. Poorer results are obtained for 1-alkanol + dibutylether mixtures with deviations up to 5%. It is shown that predictions on alpha(p), kappa(S), kappa(T), and u essentially depend on structural effects and not on the orientational effects present in the studied mixtures. Results are improved using chi(12) values fitted to molar excess volumes. In this case, deviations are similar to those obtained from semiempirical models as free length theory, collision factor theory, or Nomoto or Junjie equations. (C) 2008 Elsevier B.V. All rights reserved.