HIGH-PRESSURE VAPOR-LIQUID-EQUILIBRIA IN CARBON-DIOXIDE AND 1-ALKANOL MIXTURES

CO2 + 1-alkanol systems are of interest as solvent/co-solvent pairs in the supercritical extraction of biomaterials, in alkanol dehydration processes, in the processing of syngas, and in supercritical drying. In spite of these interests, however, only the CO2 + methanol and CO2 + ethanol systems have received much attention in the literature. Moreover, there appears to be some disagreement between the different sets of published data even for these systems. In order to compile a reliable set of data for modelling processes which involve CO2 + 1-alkanol mixtures, we have measured vapor - liquid equilibria in CO2 + ethanol, CO2 + 1-butanol, and CO2 + 1-pentanol mixtures at temperatures ranging from 314 to 337 K and pressures from 4.63 to 11.98 MPa. In this paper, we compare our data with data reported in the literature, and note trends as the 1-alkanol increases in size. The correlation of the data with a simple equation of state and an equation of state based on Statistical Associating Fluid Theory is also discussed.