Vapour-liquid equilibrium data for the recovery of 1-octanol from ternary mixtures with methanol and water

1-Octanol is a useful solvent for the extraction of methanol from its aqueous mixtures. To investigate the recovery of the 1-octanol, we determined isobaric vapour-liquid equilibrium data for homogeneous mixtures of water + methanol + 1-octanol at 101.32 kPa. The experimental data were correlated using various models for the liquid-phase activity coefficients, and compared with the predictions of group contribution methods. The UNIQUAC correlation model afforded the smallest deviations in temperature and composition, and the UNIFAC method the best predictions. Using the UNIQUAC model to calculate the liquid-phase activity coefficients, a fractional distillation column for the recovery of 1-octanol from the ternary extract was simulated for three feeds with compositions corresponding to those of extracts deriving from a liquid-liquid extraction unit. The simulation indicated recovery of the 1-octanol by distillation to be facile. Under the range of conditions studied, the recovery yield was essentially independent of the reflux ratio, whereas it was strongly dependent on the bottoms/feed flow-rate ratio, which in turn was conditioned by the concentration of 1-octanol in the feed.