Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

A highly automated 2-step method for measuring and correlating liquid-liquid equilibria (LLEs) is presented: In step 1, samples are prepared and measurements are performed; step 2 covers data extractionand correlation with thermodynamic models. The procedure has been optimised such that a samplevolume of 1 mL per LLE is sufficient for reliable measurements. The experimental setup consists of com-mercially available modules assembled such that the setup automatically prepares the sample mixtures,waits for equilibrium, takes samples, and analyses them. Gas chromatography (GC) is employed to max-imise flexibility with respect to the mixtures that can be studied. For GC analysis, neither further dilutionnor addition of an external standard is needed. In step 2, the gathered data are converted into concentra-tion data and the gE-models UNIQUAC and NRTL are adjusted to the data. The automated 2-step methodis validated for the ternary systems cyclohexane toluene methanol, isooctane o-xylene methanol, and1-octanol ethanol water. Good agreement with literature data is achieved while experimental effort isreduced significantly