Prediction of the excess volume and isobaric thermal expansion for 1-alkanol + n-alkane systems in terms of an association model with a Flory contribution term

Abstract

The predictive ability of the model proposed by Treszczanowicz and Benson [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 = ( ∂V E ∂T ) p data for 1-alkanol + alkane mixtures. The model takes into consideration the chemical effect of H-bond disruption described by an athermal-associated mixture model and the free-volume effect described by a Flory equation of state contribution. The model predicts V E and A p E well for mixtures formed by alkanols from ethanol to 1-dodecanol and n-alkanes from n-pentane to n-hexadecane. In particular, the model predicts 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-volume) contributions.