Viscosity Arrhenius Activation Energy and Derived Partial Molar Properties in Isobutyric Acid + Water Binary Mixtures Near and Far Away from the Critical Temperature, 302.15 to 313.15 K

Calculations of the viscosity Arrhenius activation energy and derived partial molar properties, from literature experimental values of viscosity in isobutyric acid + water binary mixtures from 302.15 to 313.15 K, are presented here. The close similarity between the values of the Arrhenius activation energy Ea and the enthalpy of activation of viscous flow ΔH* lead us to define the partial molar activation energies Ea1 and Ea2 for isobutyric acid and water, respectively, along with their individual separate contribution. Correlation between the two Arrhenius parameters of viscosity at all compositions shows the existence of two distinct main behaviors separated at the mole fraction in isobutyric acid equal to 0.1114. In addition, we add that correlation between Arrhenius parameters reveals the interesting Arrhenius temperature that is closely related to the vaporization temperature in the liquid–vapor equilibrium, and the limiting corresponding partial molar properties permits us to predict the boiling points of the pure components.