Relaxation and equilibrium properties of dilute aqueous solutions of alcohols

Abstract

Regularities of equilibrium state establishment in dilute aqueous solutions of alcohols and the concentration and temperature dependences of the contraction, which is one of the simplest and important thermodynamic characteristics of solutions, were considered. The equilibrium state in aqueous solutions of the alcohols is established for days and even weeks after preparation. Such a slow relaxation process is directly related to the formation of the microheterogeneous state of the system and peculiarities of its time evolution. The character of the temperature and concentration dependences of the contraction is satisfactorily explained on the basis of the simplest virial equation of state assuming that its parameters are determined by the averaged potentials of intermolecular interaction. The physical nature of peculiar points of aqueous solutions of alcohols, i.e., intersection points of the contraction curves or points in the vicinity of which the intensity of molecular light scattering anomalously increases, was considered. The appearance of peculiar points depends on orientational correlations in water. The possibility of existence of peculiar points in other binary solutions is also discussed.