Thermodynamic properties of some binary liquid mixtures containing an aromatic fluorocarbon.

The excess enthalpies, volumes and Gibbs free energies of mixing have been measured for a series of cyclic ethers with hexafluorobenzene. These results indicate the presence of a specific interaction in these systems. Use of a stronger fluorocarbon acceptor, pentafluorobenzonitrile, was found to enhance this interaction. The freezing curve of the system tetrahydropyran + hexaflucrobenzene has been determined shewing only a simple eutectic, indicating that the complex exists only in solution. Nuclear magnetic resonance studies of some of these systems gave an insight into the possible orientation of the complex. An improved static vapour pressures apparatus is described, using a liquid burette system for mixture preparation and incorporating a pressure transducer system. The freezing curves and enthalpies of mixing of some aromatic hydrocarbon systems with pentafluorobenzonitrile have been measured. The results indicate relatively strong interactions between the components of these mixtures.