Gas phase isochores and vapor pressures of pure refrigerants: difluoromethane (R 32), pentafluoroethane (R 125), 1,1,1,2-tetrafluoroethane (R 134a), and l,l,1,2,3,3,3-heptaffuoropropane (R 227ea)

Abstract

Experimental pressure-temperature (P-T) data at severa/ constant densítíes were obtained for gaseous non­ chlorinated refrigerant fiuids, difiuoromethane (R 32), pentajluoroethane (R 125), 1,1,1,2-tetrajlu.oroethane (R 134a), and 1,1,1,2,3,3,3-heptafiuoropropane (R 227ea), by using of a new constant-volume ceU constructed to work at high pressures at temperatures from 273.15 Kto 353.15 K. The vapor pressures were estimated graphically at tM break point of the measured P-T curves. The vapor pressure values were co"elated using Antoine and Wagner equations. These data, and the derived acentric factors and enthalpies of vaporization, agree within 2 to 5 % with literature values.