Temperature dependence of heat capacity and pressure for one ternary mixture of water+n-hexane+1-propanol

The investigations of the isochoric heat capacity of the 0.7168 (molar fraction) H2O+0.1058 n-C6H14+0.1774 n-C3H7OH ternary system were made at constant composition in the range of temperatures (T) 314–590 K and densities (ρ) 191.3–450.0 kg/m3 with the adiabatic calorimeter. The curves of the phase equilibrium liquid–liquid and vapour–liquid were defined from jumps of the isochoric heat capacity. The forms of the phase equilibrium curves allow determining some special points. In the interval of densities 191.3–406.5 kg/m3 both lines of phase equilibrium have the forms of parabolas. Therefore, the special points are points of a maximum, which give the possibility to evaluate the forms of the left-hand and right-hand boundary curves. The following special point is the point of intersection of curves phase equilibria liquid–liquid and vapour–liquid, where occurs the duplication of the isochoric heat capacity jump on a isochore and the point at ρ=406.5 kg/m3 and T=496.15 K, in which we observe the sharp change of solubility character of the components.