Isobaric vapor-liquid equilibrium for ethanol/water and binary linear siloxane mixtures at 100 kPa

Abstract

Isobaric vapor-liquid equilibrium (VLE) measurements are performed for ethanol/water, hexamethyldisiloxane (MM)/octamethyltrisiloxane (MDM), hexamethyldisiloxane (MM)/decamethyltetrasiloxane (MD2M) and octamethyltrisiloxane (MDM)/decamethyltetrasiloxane (MD2M) mixtures at 100 kPa using a recirculation still and Raman-spectroscopy for sample analysis. The experimental results for ethanol/water show a good agreement with the calculated values of NRTL, UNIQUAC, UNIFAC and Refprop v.10.0. For the first time, measurement data for MDM/MD2M at 100 kPa are recorded and the results of MM/MDM, MDM/MD2M and MM/MD2M reveal a good accordance with the NRTL, UNIFAC model and Refprop v.10.0. Furthermore, binary interaction parameters for NRTL and UNIQUAC are determined for the first time for the mixtures MM/MDM, MDM/MD2M and MM/MD2M. Thereby, a better description of the vapor-liquid phase equilibrium could be achieved for all three mixtures than with the conventional models using estimated binary interaction parameters from the UNIFAC model. With new binary interaction parameters from Keulen et al. for the multi-fluid Helmholtz energy equation of state for mixtures for Refprop, also a better consistency could be achieved for MM/MDM and MM/MD2M compared to the other calculation models.