Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

A computer-aided equipment for precise measurements of vapour liquid equilibrium (VLE) data at normal and low pressures using the dynamic method will be introduced. The apparatus consists of a circulation still which allows isothermal and isobaric measurements. The digital measurement and control system is accomplished by a multimeter coupled with a PC via IEEE-card. The quality of the measurement data is demonstrated by a comparison of the measured vapour pressure data of the pure substances toluene, n-octane and cyclohexylamine with the vapour pressure equation of Daubert and Danner. Furthermore, vapour liquid equilibrium data were measured in the binary systems cyclohexylamine + aniline or water or n-octane. The measured data were regressed according to the activity coefficient models NRTL, UNIQUAC and to the Elliott Suresh Donohue-equation of state (ESD-EOS).