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

High-Temperature and High-Pressure PVT Measurements of the Binary n-Hexane + Methyl Octanoate Mixture near the Critical Point of the Pure Solvent (n-Hexane)

“…As is well-known, according to the isomorphic principle − of the critical phenomena in the binary mixture, the near-critical thermodynamic behavior of the dilute mixture near the critical point of the pure solvent ( n -hexane) is controlled by the two characteristic parameters ( K 1 , K 2 ) and the characteristic reduced temperatures (τ 1 ,τ 2 ) and density differences (Δρ 1 ,Δρ 2 )­ where is the thermal–pressure coefficient of the pure solvent ( n -hexane) at the critical point; and are the initial ( x → 0) slopes of the critical lines ( P C – x and T C – x ) of the mixture calculated from our present and previously reported results; Γ 0 + = 0.042, A 0 + = 33.05, and B 0 = 1.710 are the asymptotical critical amplitudes of the isothermal compressibility, isochoric heat capacity, and liquid–gas coexistence curve of pure n -hexane, respectively, which are taken from our previous publication and other reported data; − and and are the reduced temperature and density differences, respectively. The values of the characteristic parameters K 1 and K 2 for strongly and weakly divergent properties (isothermal compressibility, K TX , or isobaric heat capacity, C PX, and isochoric heat capacity, C VX , respectively) of the binary mixture calculated from the present mixture critical curve data and pure solvent ( n -hexane) data are K 1 = −0.0218 and K 2 = 0.0267.…”