Measurement and Correlation of High Pressure Vapor–Liquid Equilibria in CO₂–Ethanol–Essential Oil Ternary Systems Applied to Supercritical Counter–Current Extractions

Abstract

Vapor–liquid equilibrium measurements in (CO₂(1)–ethanol(2)–myrcene(3)) and CO₂(1)–ethanol(2)–linalool(3)) ternary systems were carried out at temperatures of 333–373 K and pressures of 6–10 MPa with a continuous flow apparatus for selective separation of essential oil components. The experimental data were correlated with the results calculated with the Peng–Robinson equation of state combined with the van der Waals mixing rule based on fundamental critical properties estimated by a group contribution method. In counter-current extractions in CO₂(1)–ethanol(2)–myrcene(3)–linalool(3) systems for myrcene and linalool, the purity of myrcene reached about 90 mol% at 333 K and 6 MPa from an equimolar feed of myrcene and linalool. From the results of supercritical counter-current extractions, myrcene was separated from linalool, with a purity of 91 mol% for myrcene in the vapor phase.