Thermodynamic Properties of Amines under High Temperature and Pressure: Experimental Results Correlating with a New Modified Tait-like Equation and PC-SAFT

New experimental densities for diethylamine (DEA), dibutylamine (DBA), and tributylamine (TBA) at 11 isotherms in the range of 293.15-473.15 K and 18 isobars up to 37.5 MPa are reported. P rho T measurements (176 experimental data points) have been performed using a high-pressure vibrating-tube densimeter. These data were correlated with a new modified Tait-like equation considering standard deviations of less than 2 x 10(-4) g.cm(-3), and then isothermal compressibility (kappa(T)) and thermal expansion coefficient (alpha(P)) were calculated. This study is supported by the results of modeling using the perturbed-chain statistical associating fluid theory (PC-SAFT). The parameters of PC-SAFT equation of state (EoS), for pure solvents, were rigorously determined by fitting the equation to the liquid P rho T experimental data. In this study, the correlations, which are based on minimizing the total objective functions (density, pressure, and temperature) simultaneously, were developed to estimate the PC-SAFT parameters. The model reasonably predicted the behavior of P rho T and the first- and second derivative properties such as isothermal compressibility (kappa(T)), thermal expansion coefficient (alpha(P)), isobaric heat capacities (C-P), and speed of sound (u). The results undoubtedly suggest that the model performance is enhanced for either cases of the new modified Tamman-Tait equation and the PC-SAFT EoS, based on employing the proposed parameters.