Thermodynamics of Mixtures of Aromatic Hydrocarbons with Alkanols Studied by Light Scattering

Measurement of light scattering of mixtures of aromatic hydrocarbons (benzene, toluene, ethylbenzene) and alkanols (methanol, ethanol, propan-1-ol, butan-1-ol, pentan-1-ol) having sufficiently different refractive indices, produced rather reliable thermodynamic data. From these data it was possible to deduce the composition dependence of the change in Gibbs energy of mixing ∆Gmix. These dependences were measured for eleven binary mixtures. A model of alcohol molecules forming linear aggregates which are in equilibrium was developed and used for interpretation of the data. All ∆Gmix data for the eleven mixtures as well as the ∆Hmix data obtained for these mixtures from literature could be interpreted using just two values that characterized the Gibbs energy and enthalpy of the formation of hydrogen bonds. The analysis also yielded plausible results concerning the contact interactions.