Subatmospheric <i>P-T-x-y</i> Measurements and Modeling for the Butan-1-ol/Butan-2-ol + Oct-1-ene Systems in the Range of <i>T</i> = (323.2–363.2) K

The phase behaviors of alkene-oxygenate mixtures are highly nonideal and not well studied in the literature. To expand the available literature for these systems, isothermal vapor–liquid equilibrium (VLE) data were measured for the butan-1-ol/butan-2-ol + oct-1-ene systems using the dynamic circulation method. The measurements were conducted at three temperatures in the subatmospheric range (T = 333.2, 343.2, 363.2) K, and complex azeotropic behavior was observed. The data were fit using the γ-Φ formulation to the NRTL and UNIQUAC activity coefficient models combined with the virial equation of state using parameters from the Hayden-O’Connell correlation. A temperature-dependent activity coefficient model parameter term was used. The NRTL model combination generally resulted in a superior fit of the VLE data when considering deviations in pressure and vapor composition. This is attributed to the model strength and the additional regressed nonrandomness parameter. The VLE data were found to be thermodynamically consistent according to the Area, Point, and Infinite dilution tests.