Temperature dependence of the excess molar volume of 1-hexanol + 1-alkene systems in terms of an association and equation of state model

Excess molar volumes VE measured at 288.15 and 308.15 K for (1-hexanol + 1-hexene), (1-hexanol + 1-octene) and (1-hexanol + 1-decene) systems are reported. The data and the measurements reported before at 298.15 K for this series of mixtures were used to estimate the excess molar isobaric thermal expansion ApE=(∂VE/∂T)p and the partial molar excess isobaric thermal expansions Ap,iE of the components at 298.15 K. The ApE as a function of concentration, changes from positive–negative for the systems formed by short-chain 1-alkenes like 1-hexene to positive for 1-decene over the whole concentration range. The modified Treszczanowicz and Benson model (TB) is applied to interpret and to predict changes in the size and shape of the ApE and Ap,iE curves. The model predicts qualitatively well the changes of the ApE and Ap,iE values in the series of mixtures as a superposition of the contributions due to self-association of alkanol, free volume, OH⋯π interactions and residual van der Waals interactions. These contributions to the properties investigated are estimated and discussed in the series of mixtures. The results obtained are compared with those for 1-alkanol + n-alkane systems.