The physical properties, boiling point, critical temperature, critical pressure, liquid, and critical densities are investigated for the fluorinated ethers RE-218 (CF₃OCF ₂ CF₃ ) and RE-143a (CF₃ OCH₃ ) and the ether mixtures, RE-143a/RE-218, which are potential alternatives for R-12 or R-22. The vapor pressures of the RE-143a/RE-218 mixture were measured over the entire concentration range for temperatures starting from well below their boiling points up to their normal boiling points. The mixtures form an azeotrope at 0.5 RE-143a mole fraction with a normal boiling point of -30°C (-22°F), a critical temperature of 87.9°C (190.2°F), and a critical mixing temperature of well below -70°C (-94°F). The vapor pressure of the azeotropic mixture was measured up to the critical point. The potential of the azeotropic mixture as an R-12 or R-22 alternative relative to existing alternatives is discussed.

This paper also published as DA-00-10-4, part of Symposium DA-00-10, Properties Update

Units: Dual