Properties of novel fluorinated compounds and their mixtures as alternative refrigerants

The liquid density, boiling point, critical temperature and critical density are investigated for R-161 (CH3CH2F, bp=−37.3°C), CF3SCF3 (bp=−20.1°C), and RE-218 (CF3OCF2CF3, bp=−23.7°C); which are potential R-12 and R-22 alternatives. Since the range of applicability of chemicals may be improved by considering their mixtures, the vapor pressure of the mixtures; CH3CH2F/CF3SF5, CF3CH2F/CF3SF5, and CF3(CF2)2CH2F (R-338mccq)/isopentane; were also investigated. The critical mixing temperature of the CH3CH2F/CF3SF5 mixtures is above −30°C which is greater than the normal boiling point of −40°C. Therefore, these mixtures would have limited application as R-12 and R-22 alternatives. The normal boiling point of the R-134a (CF3CH2F)/CF3SF5 mixtures at the azeotropic R-134a mole fraction, 0.60, is −30.0°C. The critical mixing temperature of the latter mixtures is well below the boiling point and is not a factor in refrigeration applications. The CF3(CF2)2CH2F (R-338mccq)/isopentane mixtures have a normal boiling point of 15.1°C and a critical mixing temperature of about −5°C which may be acceptable for some applications as a R-11 alternative.