Influence of Modifier in Supercritical CO 2 on Qualitative and Quantitative Extraction Results of Eucalyptus Ecential Oil

Abstract

A supercritical CO2 extraction behavior of Eucalyptus oil was investigated under different conditions of pressure, temperature and time with or without cosolvent. The pressure range was from 8 to 25 MPa, temperature from 35 to 55˚C and CO2 flow rate from 10 to 26 g/min. For 1,8-cineole the appropriate extracting pressure was 15 MPa and temperature was 45˚C. When CO2 flow rate was 18 g/min, it was benefit to extract the other three substances (limonene, p-cymene and γ-terpinene, respectively) except 1,8-cineole. Prolonging extraction time could not obviously increase the extract concentration, but the extract yield would increase. The results also indicated that ethanol as a modifier could improve extraction velocity and extraction concentration.