Sublimation Pressure of Low-volatile Solids from High Pressure Solubility Data Using Genetic Algorithms

Sublimation pressure of pure solids are calculated from high pressure solubility data using genetic algorithms. The Peng-Robinson equation of state with the mixing rules proposed by Wong and Sandler are used as the thermodynamic model to evaluate the fugacity coefficients in the classical solubility equation. The sublimation pressure is considered as a parameter to be determined by regression analysis of experimental solubility data. Four gas-solid systems, including 13 isotherms and a total of 254 PTy data points were used for the study. The systems considered were binary mixtures containing supercritical carbon dioxide with naphthalene, phenanthrene, capsaicin and B-carotene. The proposed method allows to calculate sublimation pressures of the solids considered in this study with high accuracy.