Measurement of Phase Equilibrium for R-1233zd(E) with Three Pure Esters between 298.15 and 343.15 K

The increasing concerns of the global warming impact of traditional refrigerants (R-410a, R-245fa, R-134a, R-404a, etc.) drive the requirement for substitutes more compelling. Due to the remarkable properties (near-zero ozone depletion potential, ultralow global warming potential, nonflammable, nontoxic, high normal boiling point, etc.), trans-1-chloro-3,3,3-trifluoropropene (R-1233zd(E)) is attracting a great deal of attention in high-temperature heat pumps, chillers, and organic Rankine cycles. To increase the phase-equilibrium database for R-1233zd(E) with lubricants, the vapor–liquid phase equilibrium was measured for R-1233zd(E) in three pure polyol esters (PEC4, PEC6, and PEC8) from 298.15 to 343.15 K using an isochoric saturation method. Phase equilibrium of R-1233zd(E)/oil mixtures was successfully correlated by the NRTL model. The results show that the solubilities increase with increasing pressure and decrease with rising temperature. In addition, no liquid–liquid phase and vapor–liquid–liquid split were found. The solubilities of R-1233zd(E) in different PEC oils indicate that the solubility order increases from PEC4 to PEC8.