Vapor–liquid equilibria for CF3OCF2H/fluorinated ethane and CF3SF5/fluorinated ethane mixtures as potential R22 alternatives

New vapor pressure data are reported as a function of temperature and concentration for the mixtures: CF3SF5/CF3CH3, CF3SF5/CF3CF2H, CF3OCF2H/CH3CH2F, CF3OCF2H/CH3CF2H, CF3OCF2H/CF3CH3, CF3OCF2H/CF3CH2F, and CF3OCF2H/CF3CF2H. As is expected, large positive deviations from the ideal mixing vapor pressure are observed for CF3SF5 mixed with ethane derivatives of a low fluorine content and these deviations become small as the fluorine content approaches that of CF3CF2H. In contrast to this expected vapor pressure behavior, the ether (CF3OCF2H)/fluorinated ethane mixtures exhibit significantly smaller deviations which may be positive or negative. The mixture, CF3OCF2H/CH3CH2F, exhibits sufficiently large negative deviations from ideality to produce an azeotrope at 0.21 mol fraction of CH3CH2F with boiling point of −33.3°C. The mixtures CF3OCF2H/CH3CF2H, CF3OCF2H/CF3CH3 and CF3OCF2H/CF3CF2H are nearly ideal and the mixture CF3OCF2H/CF3CH2F exhibits positive deviations from ideality. All of the mixtures have boiling points that range from −22 to −48°C. The mixtures that have boiling points below −30°C have potential as R22 alternatives.