Location: Functional Foods ResearchTitle: Determination of crossover pressure for cedarwood oil in carbon dioxide
Submitted to: Journal of Supercritical Fluids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2018
Publication Date: 12/21/2018
Citation: Eller, F.J., Teel, J.A. 2019. Determination of crossover pressure for cedarwood oil in carbon dioxide. Journal of Supercritical Fluids. 145:201-204. https://doi.org/10.1016/j.supflu.2018.12.014.
Interpretive Summary: Eastern red cedar is an abundant renewable resource and represents a vast potential source of valuable natural products that may serve as natural biocides. Eastern red cedar (Juniperus virginiana L.) (Cupresseaceae) wood is the source of cedarwood oil (CWO), a valuable commodity used for perfumes, insecticides, and repellents. The wood from Eastern red cedar was extracted using liquid carbon dioxide (CO2) (i.e., 25ºC) as well as supercritical CO2 (i.e., or 85ºC) at pressures ranging from 1000 to 5000 psi. This research determined that at ca. 3453 psi, regardless of the extraction temperature, the solubility of cedarwood oil (CWO) in carbon dioxide (CO2) was equivalent. These results will be used to design efficient methods to extract CWO from juniper wood. This CWO could be used as a renewable source of natural materials while providing a source of income for farmers and ranchers as well as meet consumer demand for safe products.
Technical Abstract: A series of solubility experiments were conducted to determine the crossover pressure for cedarwood oil (CWO) in CO2. A closed stirrer reactor with an in-line loop connected to the injector of a GC was used to measure the concentration of CWO in the CO2. Cedarwood oil was placed inside the stirrer reactor and combinations of two temperatures (i.e., 25ºC or 85ºC) in conjunction with nine pressures (i.e., 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, or 5000 psi) were tested. The solubility of a commercial CWO was determined from the FID counts from the GC analysis. In addition, the CWO compositions in the CO2 were also monitored. At pressures below ca. 3000 psi, the solubility of CWO was higher in liquid CO2 (i.e., 25ºC) than supercritical CO2. From the data, the crossover pressure for CWO in CO2 was calculated to be ca. 3453 psi. The solubility isotherms for CWO in CO2 were similar to those previously reported for triglycerides in CO2, although the crossover pressure was shifted to a much lower pressure. The crossover pressure calculated from the extraction of CWO from juniper sawdust and collected CWO mass was significantly lower (i.e, 2679 psi) than that determined by the stirred reactor and FID counts.