PREDICTION OF THE EXCESS VOLUME AND ISOBARIC THERMAL-EXPANSION FOR 1-ALKANOL PLUS N-ALKANE SYSTEMS IN TERMS OF AN ASSOCIATION MODEL WITH A FLORY CONTRIBUTION TERM

The predictive ability of the model proposed by Treszczanowicz and Ben son [A.J. Treszczanowicz, G.C. Benson, Fluid Phase Equilib. 23 (1985) 117] is tested for all available excess volume V-E and excess thermal expansion A(p)(E) = (partial derivative V-E/partial derivative T)(p) d ata for 1-alkanol + alkane mixtures. The model takes into consideratio n the chemical effect of H-bond disruption described by an athermal-as sociated mixture model and the free-volume effect described by a Flory equation of state contribution. The model predicts V-E and A(p)(E) we ll for mixtures formed by alkanols from ethanol to 1-dodecanol and n-a lkanes from n-pentane to n-hexadecane. In particular, the model predic ts an intersection point for series S-shaped V-E and A(p)(E) isotherms . This phenomenon is discussed as resulting from a balance between the positive (association, non-specific interactions) and negative(free-v olume) contributions. (C) 1997 Elsevier Science B.V.