THE CRITICAL PROPERTIES OF PERFLUORO N-ALKANES

The critical temperatures, pressures and densities of four perfluoro n -alkanes (perfluoropentane, perfluorohexane, perfluoroheptane and perf luorooctane) have been measured using a sealed ampoule method and a lo w residence time flow method. Our data have been compared with literat ure data whenever possible and several inconsistencies in the literatu re data have been resolved by the present work. Available literature d ata on the critical properties of all perfluoro n-alkanes have been co mpiled and trends in the data with chain length of the perfluorocarbon are noted. The performance of several group contribution methods has also been examined and shown to be generally poor for the prediction o f critical properties of the homologous series of perfluoroalkanes.