Solubility of large crown ethers in supercritical carbon dioxide

The equilibrium solubilities of dibenzo-24-crown-8 (DB24C8), dibenzo-27-crown-9 (DB27C9), and dibenzo-30-crown-10 (DB30C10) have been measured in supercritical carbon dioxide. The measurements were performed in the pressure range from 120 to 440 atm at temperatures 35, 45, 55 and 65°C for DB24C8 and in the pressure range from 120 to 480 atm at temperatures 35, 45, 55, 65 and 75°C for DB27C9 and DB30C10. The solubility of the crown ethers in supercritical carbon dioxide was found to vary in the order DB24C8>DB27C9⪢DB30C10. The measured solubilities were correlated using a semi-empirical model. The calculated results show satisfactory agreement with the experimental data.