A New Model for the Solubility of Solids in Supercritical Fluids

This work deals with a new approach for the calculation of solubility of organic solids in supercritical fluids using equations of state. The novelty of the approach is the use of the critical properties and vapor pressure of the solute as adjustable parameters. Calculations are presented with the Peng-Robinson equation of state. The values of the interaction parameter, critical properties, and vapor pressure were obtained by minimizing an objective function with the Fibonacci (Golden Section) optimization method. The calculations were made based on experimental data for which there were at least three different solvents for each solute to compare critical properties of the solute obtained from different solute-solvent combinations. The results are encouraging since the critical properties for the same solute in different solvents are similar. The sublimation pressures obtained by this technique at different temparatures followed a van't Hoff trend.