Solubility of non-psychoactive cannabinoids in supercritical carbon dioxide and comparison with psychoactive cannabinoids

The solubilities of two different non-psychoactive cannabinoids i.e., cannabigerol (CBG) and cannabidiol (CBD), in supercritical carbon dioxide (CO2) have been determined at 315, 326 and 334 K and in the pressure range from 11.3 to 20.6 MPa. These solubility data have been compared to the previously determined solubilities of two psychoactive cannabinoids i.e., (−)-Δ9-tetrahydrocannabinol (Δ9-THC) and cannabinol (CBN), in supercritical CO2. An analytical method with a quasi-flow apparatus was used for the experimental determination. Within the investigated temperature and pressure range, the molar solubility of CBG ranged from 1.17 to 1.91 × 10−4 and the molar solubility of CBD ranged from 0.88 to 2.69 × 10−4. The solubility of the different cannabinoids in supercritical CO2 increases at 326 K in the following order: Δ9-THC < CBG < CBD < CBN. The solubility data were correlated using the Peng–Robinson equation of state in combination with Van der Waals mixing rules. Deviations between calculated results and the experimental data ranged from 0.81 to 6.35% absolute average relative deviation (AARD), except for CBD at 334 K, where the AARD was 18.4%.