Phase behavior of the binary system ethane+linalool

As part of a study to assess the capacity of supercritical fluids in deterpenating citrus essential oils, high-pressure vapor–liquid equilibria of the binary system ethane+linalool were determined experimentally. Bubble and dew points were measured at ethane mole fractions ranging from 0.2 to 0.9998 and within temperature and pressure ranges of 278–368 K and 2.6–11.4 MPa, respectively. This binary system also exhibited a region of liquid–liquid two-phase split, resulting in the presence of a three-phase liquid–liquid–vapor equilibrium. Experimental values of the upper and lower critical endpoints, in addition to normal critical points are presented. From the experimental results it could be concluded that the system ethane+linalool shows type-V fluid phase behavior in the classification of Van Konynenburg and Scott. The experimental results also show the interesting phenomenon of double retrograde vaporization, in which the dew point curve has a double-domed shape. In this limited region, increasing the pressure at fixed concentration results in triple- or quadruple-valued dew points. The experimental results were correlated by the Stryjek–Vera modified version of the Peng–Robinson equation of state using the Mathias–Klotz–Prausnitz mixing rule.