Experimental study of the one-, two-, and three-phase isochoric heat capacities of n-hexane + water mixtures near the lower critical line. Part II. Krichevskii parameter and thermodynamic and structural properties

Abstract Using the experimental isochoric heat capacity, vapor-pressure data for the pure solvent ( n -hexane), and the critical properties data for n -hexane + water mixtures reported in the first part of this paper the value of the Krichevskii parameter was calculated. The thermodynamic ( V ¯ 2 ∞ , H ¯ 2 ∞ , K D ∞ , B 12 ) and structural ( N exc ∞ , C 12 , H 12 ) properties of dilute n -hexane + water mixture near the critical point of pure solvent ( n -hexane) were calculated using the Krichevskii parameter principle. The measured, in the first part of this paper, C VX behavior and saturated density ( T S , ρ S ) data of the mixtures near the critical points have been analyzed and interpreted in terms of isomorphism of the critical phenomena in binary mixtures. Measured critical lines data for the mixtures together with vapor-pressure data for pure solvent ( n -hexane) were used to accurately calculate the values of the characteristic parameters ( K 1 , K 2 ), temperatures ( τ 1 , τ 2 ), and the characteristic density differences ( Δρ 1 , Δρ 2 ). The derived values of the characteristic parameters were used to analyze the critical behavior of the strong ( C P , K T ) and weakly ( C V ) singular properties in terms of the principle of isomorphism of critical phenomena in binary mixtures.