Purification of sclareol by supercritical CO2 fractionation process

The implementation and optimization of continuous supercritical CO2 fractionation of a clary sage extract containing 25 wt% of sclareol were performed in order to increase its sclareol content. After preliminary experiments confirming the feasibility of the process, different operating conditions were studied: CO(2-)over-feed mass ratio from 25 up to 115, and pressure between 11 and 13 MPa, with an internal reflux due to a thermal gradient 323-338 K along the column, through an experimental design. Four responses were highlighted: sclareol mass fraction in the raffinate, sclareol mass fraction in the extract, sclareol yield in the raffinate, and the amount of an undesirable compound exhibiting a similar behaviour to sclareol and thus, hard to separate from sclareol by conventional techniques. This work allowed us to highlight the best operating conditions: a pressure of 12.6 MPa and a CO2-over-feed mass ratio of 114.5 leading to a sclareol mass fraction in raffinate and extract of 75.3% and 4.6% respectively, to a sclareol yield of 82.4% in the raffinate, and to an amount of 0.08% of the undesirable compound in the raffinate. (C) 2016 Elsevier B.V. All rights reserved.