Measuring and Modeling the Density of Some Typical Binary Mixtures in the Conditions of 280–423.15 K and 0.1–9 MPa

In order to investigate the interactive effect on the density of two-component mixtures, six mixtures of methylcyclohexane(1) + n-dodecane(2)/n-tetradecane(2)/n-hexadecane(2) and ethylcyclohexane(1) + n-dodecane(2)/n-tetradecane(2)/n-hexadecane(2) were measured by using the Anton Paar DMA 4200 M densimeter and a hand-operated pressure pump in the temperature and pressure ranges of T = 280 to 423.15 K and P = 0.1 to 9 MPa, respectively. Additionally, the combined standard uncertainty in the density of binary mixtures with n-hexadecane is uc(ρ) = 1.543 kg/m3, and for other mixtures, it is uc(ρ) = 1.541 kg/m3. The experimental data were successfully correlated with the empirically modified Toscani–Szwarc equation of state with a maximum regression deviation of less than 1.0630 kg/m3 for all the binary mixtures. On the basis of the experimental data and parameters of the regression model, isobaric thermal expansivity and isothermal compressibility were calculated and exhibited nonlinear behavior against the mole fraction, which is due to different molecular interactions between the two components.