Rose concrete fractionation by supercritical CO2

Supercritical CO2 extraction was used to post-process a solid rose extract produced by liquid solvent extraction. Single step supercritical extraction at 80 bar, 40 °C, and a two-stage separation procedure at 80 bar and −16 °C and at 15 bar and 0 °C, were the optimum process conditions to produce a volatile rose oil with an overall 2-phenyl ethanol content of 50.0%. This result is particularly noteworthy since this compound is water soluble and most of it is lost when steam distillation is used. Moreover, a very low content of undesired compounds like paraffins and long chain alcohols was obtained in the final product. The extraction/fractionation process evolution and its optimization was monitored by performing systematic GC-MS analysis of the extracts. These analysis indicate a large influence of the extraction time on the composition of volatile rose oil. Therefore, to obtain an accurate reproduction of rose fragrance, extraction and separation conditions as well as the duration of the extraction process must to be optimized.