Nikita A. Kovalenko

Thermodynamic properties of solutions in the system o-xylene–di-2(ethylhexyl)phosphoric acid

The saturated vapor pressure in the temperature range of 298.15–308.15 K and the density of solutions in the o-xylene–di-2(ethylhexyl)phosphoric acid system at 298.15 K are measured. The activity coefficients of o-xylene in the above temperature range are calculated on the basis of the resulting data. The parameters of the thermodynamic model UNIQUAC are determined and analytical relationships are proposed to describe the bulk properties of the solution.

Phase equilibria in water-(1-, 2-, iso-)butanol-18-crown-6 systems

We present the results from measuring the solubility of 18-crown-6 in isobutanol in the temperature interval of 280–308 K and information about liquid-liquid equilibria in water-(1-, 2-, iso-)butanol-18-crown-6 systems at 298 K. The parameter values of the extended UNIQUAC model were determined on the basis of information about the thermodynamic properties and phase equilibria in the binary systems. It is shown that we must use parameters of ternary interaction in addition to binary parameters to adequately describe the miscibility gap on the basis of the results of turbidimetric titration in ternary water-(1-,2-, iso)butanol-18-crown-6 systems.