Modeling of supramolecular ordering and physicochemical properties in cyclohexane-ethanol mixtures

The quasichemical model of the nonideal associated solution (QCNAS) was used to analyze the excess thermodynamic functions and permittivity of cyclohexane-ethanol mixtures in the entire range of compositions and in a wide temperature range. A new model of supramolecular organization was substantiated, taking into account chain and cyclic aggregation of alcohol with the formation of chain aggregates of arbitrary size, which describes a set of physicochemical properties of this mixture with complicated behavior of both thermodynamic and dielectric properties. Equilibrium constants and thermodynamic parameters of H bonding having cooperative character and integral and differential characteristics of aggregation and the structural parameters of aggregates were determined. It was established that the role of nonpolar cyclic structures increases as alcohol concentration decreases. The model describes the permittivity of solutions in the entire range of compositions and reproduces a minimum of the dipolar correlation factor in the range of dilute alcohol solutions. The new data obtained on the supramolecular ordering characterized by the long-range molecular correlations due to H bonding are discussed in detail.