Prediction of solid solute solubility in supercritical carbon dioxide with organic cosolvents from the PR+COSMOSAC equation of state

Supercritical carbon dioxide (ScCO₂) plays an important role in industries, such as in the purification/crystallization processes in the pharmaceutical industry, in the extraction of natural flavors and nutrients in the food/pharmaceutical industry, and in wafer cleaning in the semiconductor industry. Therefore, the solubility of solid solutes in ScCO₂, with and without organic solvents, is essential information for the design and optimization of such processes. It has been shown that PR+COSMOSAC EOS is able to provide a reasonable prediction accuracy for drug solubility in organic solvents and in ScCO₂. In this study, PR+COSMOSAC EOS is applied to predict the solubility of solid solutes in mixtures of ScCO₂ + organic solvents (e.g., acetone and ethanol). The solubility of 23 solid solutes in different mixtures of ScCO₂ + organic solvents with pressures up to 40 MPa and temperatures ranging from 298.15 K to 353.15 K are used to evaluate the accuracy of PR+COSMOSAC EOS. The overall average logarithmic deviation (ALD-x) in the prediction of drug solubility in binary ScCO₂ + organic solvent mixtures is 0.76. The accuracy is slightly better than that of the drug solubility in pure ScCO₂ and similar to that in pure organic solvents. This study shows that PR+COSMOSAC EOS may be a useful tool in predicting the solubility of solid solutes when no experimental data are available.