Thermodynamic Properties of 1,2-Dichloroethane and 1,2-Dibromoethane under Elevated Pressures: Experimental Results and Predictions of a Novel DIPPR-Based Version of FT-EoS, PC-SAFT, and CP-PC-SAFT

This study reports the experimental measurements of speeds of sound from 293.15 to 313.15 K and pressures up to 100 MPa in 1,2-dichloroethane, and up to 45 MPa in 1,2-dibromoethane, approaching solidification of this compound. In addition, new atmospheric pressure data on densities of 1,2-dichloroethane from 278.15 to 348.15 K are presented. These experimental data have been implemented for calculating densities, isobaric heat capacities and coefficients of thermal expansion, isentropic and isothermal compressibilities, and internal pressures as functions of pressure and temperature by using an acoustic method of Davis-Gordon-Sun. Development of a new Design Institute for Physical Properties (DIPPR)-based version of the fluctuation theory-based Tait-like equation of state (FT-EoS) is presented. This model could become a simple and reliable tool implementing the DIPPRs saturated state expressions for predicting the high-pressure densities and speeds of sound. It has also been demonstrated that both compounds under consideration can be included in the applicability range of the predictive critical point-based perturbed-chain statistical association fluid theory (CP-PC-SAFT) approach employing the DIPPRs critical constants. In spite of its poor modeling of vapor pressures of these substances away from their critical points, CP-PC-SAFT appears as a robust estimator of various thermodynamic properties of both pure compounds and mixtures in the entire pressure range, and as well of the high-pressure phase equilibria. Unlike CP-PC-SAFT, parametrization of PC-SAFT comprises fitting large experimental databases, and it cannot be implemented for simultaneous modeling of the critical and the subcritical states. Although this model is the less successful estimator of sound velocities and compressibilities, it has a doubtless advantage in modeling the low-pressure phase equilibria.