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

Abstract

Excess molar volumes V E 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 A p E = ( ∂ V E / ∂ T ) p and the partial molar excess isobaric thermal expansions A p , i E of the components at 298.15 K. The A p E 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 A p E and A p , i E curves. The model predicts qualitatively well the changes of the A p E and A p , i E 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.