EBULLIOMETRIC MEASUREMENT OF THE VAPOR-PRESSURE OF 1-CHLORO-1,1-DIFLUOROETHANE AND 1,1-DIFLUOROETHANE

The vapor pressures of 1-chloro-1,1-difluoroethane (R142b) and 1,1-dif luoroethane (R152a) have been measured at temperatures between 224.8 a nd 284.7 K for R142b and between 219.9 and 273.1 K for R152a by a comp arative ebulliometric technique. Our results have been combined with s elected published results to provide a smoothing equation for the vapo r pressure. For R142b, our equation is valid from 200 to 300 K while f or R152a the temperature range goes from 215 K to the critical tempera ture, near 386 K.