High pressure vapor–liquid equilibrium for the ternary system ethanol/(±)-menthol/carbon dioxide

Abstract

In this work the phase behavior of the ternary system ethanol/(±)-menthol/CO2 was studied at the temperatures of 313 and 323K, in the pressure range 8–10MPa. Experiments were performed using a high pressure phase equilibrium apparatus with a visual cell. CO2 is more selective toward ethanol, separation factors ranging from 1.6 to 7.6 at the conditions tested. The pTxy data obtained were correlated with the Peng–Robinson equation of state combined with the Mathias–Klotz–Prausnitz mixing rule. The model gave a good fitting to the data, with a total average absolute deviation of 3.7%, and was able to predict the occurrence of a three-phase region observed experimentally at 313K and 9MPa.