Measurement and correlation of solubility of benzamide in supercritical carbon dioxide with and without cosolvent

The experimental equilibrium solubility of benzamide in supercritical carbon dioxide was measured at temperatures between 308 K and 328 K and for pressures from 11.0 MPa to 21.0 MPa using a dynamic flow method. The effects of three cosolvents – ethanol, acetone and ethylene glycol, were investigated at a cosolvent molar concentration of 3.5%. The results showed that the solubility was enhanced by the presence of the three cosolvents, and ethanol exhibited the highest cosolvent effect. The solubility data in the absence and presence of cosolvents were correlated by two density-based models. The calculated results showed satisfactory agreement with the experimental data.

Comparison of solubility isotherms of benzamide in supercritical carbon dioxide at 318 K.Figure optionsDownload as PowerPoint slideHighlights
► We determined the solubility of benzamide in supercritical carbon dioxide with and without cosolvent for the first time, using a flow-type apparatus.
► The cosolvent effect for the three investigated cosolvents is: ethanol > acetone > glycol. The strong attractive molecular interactions between ethanol and benzamide could enhance the solubility by up to 11 times.
► The correlated results using two density-based models show satisfactory agreement with the experimental data.