Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The surface tension of binary mixtures of heavy water and homologous series of aliphatic alcohols (methanol, ethanol and 1-propanol) were measured over the entire concentration range at various temperatures. The surface tensions of these aqueous binary mixtures show more concentration dependence on the heavy eater-rich side. Addition of a small amount of alcohol reduces the surface tension of heavy water drastically. The surface thermodynamic functions such as surface entropy and surface enthalpy have been derived from the temperature dependence of the surface tension values. The magnitude of these thermodynamically quantities is discussed in terms of the nature and type of intermolecular interactions in binary mixtures. The presence of a maximum point in the surface entropy diagram in all systems is explained by the formation of clathrate-like solvates at the surface of these systems. The surface tensions of the above mentioned binary systems were correlated with empirical and thermodynamic based models. The Myers-Scott (MS) model with three adjustable parameters gives good results when delta-sigma are large.