Retention of halocarbons on a hexafluoropropylene epoxide-modified graphitized carbon black II. Ethane-based compounds

Abstract

The retention characteristics of 18 ethane-based chlorofluorocarbon, bromochlorofluorocarbon and fluorocarbon fluids have been studied as a function of temperature on a stationary phase consisting of a 5% (mass/mass) coating of a low-molecular-mass polymer of hexafluoropropylene epoxide on a graphitized carbon black adsorbent. Measurements were made at −20, 0, 20 and 40°C for hexafluoroethane (R-116), pentafluoroethane (R-125), 1,1,2,2-tetrafluoroethane (R-134), 1,1,1,2-tetrafluoroethane (R-134a), 1,1,2-trifluoroethane (R-143), 1,1,2-tri-fluoroethane (R-143a), 1,1-difluoroethane (R-152a), and fluoroethane (R161). Measurements were made at 40, 60, 80 and 100°C for 1,2-dichlorotetrafluoroethane (R-114), 1,1-dichlorotetrafluoroethane (R-114a), chloropentafluoroethane (R-115), 2,2-dichloro-1,1,1-trifluoroethane (R-123), 2-chloro-1,1,1- trifluoroethane (R-133a), 1,1-dichloro-1-fluoroethane (R-141b), 1-chloro-1,1-difluoroethane (R-142b), and 1-chloroethane (R-160). Measurements were performed at 60, 80, 100 and 120°C for 1-bromo-2-chlorotetrafluoroethane (R-114B1). Net retention volumes, corrected to a column temperature of 0°C, were calculated from retention time measurements, the logarithms of which were fitted against reciprocal thermodynamic temperature. The relative retentions, also as a function of temperature, were calculated with respect to the retention of tetrafluoromethane and hexafluoroethane. Qualitative features of the data are examined, and trends are identified. In addition, the data were fitted to linear models for the purpose of predicting retention behavior of these compounds to facilitate chromatographic analysis.