Extraction of Natural Substances with Supercritical Gases, 10. Communication: Qualitative and Quantitative Determination of Solubilities of Steroids in Supercritical Carbon Dioxide

The solubility of 35 steroids in supercritical carbon dioxide at 40°C was examined qualitatively and quantitatively for the pressure range between 80 and 200 bat. Relations between structure of the compound and its solubility were established and rules of thumb worked out which enable us to estimate the solubility of a steroid in an extraction with supercritical gases, based upon the number of hydroxyl and carboxyl groups of the steroid basic structure. In the most favourable case we obtained solubilities of sterols with approximately 1 mg/Nl at 200 bar. All compounds with more than three hydroxyl or carboxyl groups in the molecule, and the corresponding glycosides are insoluble.