Terpenes, main constituents of essential oils, commonly called “essences”, are widely spread both in the animal and plant kingdoms in the form of apparently different substances but all united by the same basic structure, all recognized as multiples of the compound 2 -methyl-1,3-butadiene or isoprene.
Supercritical CO2 has an excellent yield and produces high quality terpene mixes as the temperatures involved are very low and therefore do not undergo the typical deterioration associated with high temperatures. The extraction of terpenes into supercritical CO2 is very fast and takes place at low pressure (about 80 bar) and low temperature (about 45 ° C). Terpenes dissolve under relatively low conditions, just above the supercritical values for CO2. The extraction of CO2 with supercritical CO2 produces a clear extract, rich in essential oils in which the terpenes are dissolved.
The high selectivity of the supercritical CO2 allows to obtain a high purity.