Experimental investigation of the thermal properties of a binary $n$-hexane–water mixture at high temperatures and pressures

The results are presented of an experimental investigation of the thermal properties of a binary $n$–$\mathrm{C}_6\mathrm{H}_{14}+\mathrm{H}_2\mathrm{O}$ mixture (system) in the ranges of temperature from $372.75$ to $690.55$ K, density from $66.87$ to $834.30$ kg/m, and pressure from $0.4$ to $65.7$ MPa. Measurements are performed for seven values of water concentrationx (in molar fractions), namely, $0.166$, $0.257$, $0.347$, $0.615$, $0.827$, $0.935$, and $0.964$. The investigations cover the region of liquid-vapor phase equilibrium and extend further into the homogeneous region. In order to describe the $P$–$V$–$T$–$x$ properties of a binary $n$-hexane-water mixture, the Soave–Redlich–Kwong formula is used (the average error is $3\%$, and the maximum error is $8\%$). Based on the scaling equations, the critical indices and amplitudes for the curves of liquid–vapor coexistence are calculated for three values of water concentration.