Equilibrium Thermophysical Properties of CO ₂ + Cyclohexanol + Toluene Mixtures at <i>T</i> = 293.15–353.15 K and <i>p</i> = 0.1–30 MPa

Equilibrium thermophysical properties of ternary carbon dioxide (CO2) + cyclohexanol + toluene mixtures were investigated at temperatures of 293.15–353.15 K and pressures of 0.1–30 MPa. The study covered phase behavior, density, and Henry’s law constant. Measurements focused on the binary cyclohexanol/toluene (70 wt %/30 wt %) mixture and its combinations with CO2 across 11 mole fractions (0.1004–0.9747 mol/mol). A high-pressure cell with adjustable volume facilitated bubble and dew point pressure detection via visual phase transition observation, yielding saturation pressures from 1.67 to 15.90 MPa. Density data were acquired using a vibrating U-tube densimeter. Phase transition analysis revealed liquid–liquid immiscibility at CO2 mole fractions exceeding 0.6 mol/mol. Molecular simulations estimated the density and Henry’s law constant for the ternary mixture and its binary subsystem (cyclohexanol + toluene). At lower temperatures (293.15 and 303.15 K), density increased with rising CO2 mole fraction. At higher temperatures (333.15 and 353.15 K), density rose for low CO2 mole fractions (0.1–0.3 mol/mol) while decreasing at higher fractions (0.4–0.6 mol/mol). Experimental and simulated density values showed an average deviation of 1.6%, peaking at around 2.8%.