Vapor–liquid equilibrium data for the sulfur dioxide (SO2) + 1,1,1,2,3,3,3-heptafluoropropane (R227ea) system at temperatures from 288.07 to 403.19 K and pressures up to 5.38 MPa: Representation of the critical point and azeotrope temperature dependence

Isothermal vapor–liquid equilibrium data have been measured for the binary system SO2 + R227ea (1,1,1,2,3,3,3-heptafluoropropane) at 10 temperatures between 288.07 and 403.19 K, and at pressures in the range 0.276–5.38 MPa. The peculiarity of this system is the existence of an azeotrope. The experimental method used in this work is of the static-analytic type, taking advantage of two pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in the Cenerg/TEP laboratory. The data were obtained with uncertainties within ±0.02 K, ±0.0015 MPa and ±1% for molar compositions. othermal P, x, y data are well represented with the Peng–Robinson equation of state using the Mathias Copeman alpha function and the Wong–Sandler mixing rules involving the NRTL model.