Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

In this paper, the (vapour + liquid) phase equilibrium for the (isobutane + cis-1,3,3,3-tetrafluoropropene) system was measured by the static-analytical method at six temperatures from (303.150 to 353.150) K. The combined standard uncertainties of the temperature, pressure and composition were less than +-5 mK, +-0.0005 MPa and +-0.005, respectively. The experimental results were correlated by means of the Peng Robison (PR) equation of state (EoS) with Van der Waals (VDW) mixing rule and Huron Vidal (HV) mixing rule involving the non-random two-liquid (NRTL) activity coefficient model. Good consistency is found by both models. The average absolute relative deviations of pressure are between 0.44% and 0.58% for the PR-VDW model, while the average absolute relative deviations of pressure are between 0.12% and 0.44% for the PR-HV-NRTL model. The average absolute deviations of vapour phase mole fraction lay between 0.007 and 0.008 for the PR-VDW model, while the average absolute deviations of vapour phase mole fraction lay between 0.004 and 0.008 for the PR-HV-NRTL model. The results show that the PR-HV-NRTL model has better performance than that of the PR-VDW model for the binary system. Obviously an azeotropic behaviour can be observed for the system.