Prediction of Solubility of Psoralea Corylifolia L. Seed Extract in Supercritical Carbon Dioxide by Equation of State Models.

Solubility of bakuchiol and psoralen, key components of Psoralea corylifolia L. seed extract, in
supercritical carbon dioxide was predicted by employing well known Peng–Robinson and Soave�modified
Redlich–Kwong equations of state. Solubility (in mole fraction) of both bakuchiol and psoralen was in the
range 10–6–10–4 for the pressure 22 to 30 MPa. Both the models were found to agree with the experimental
solubilities of psoralen very well with average deviation less than 9%. If the extract was assumed as a single
pseudo�component having average critical properties of main components, the model predicted solubility of
the extract well with average deviation less than 17%. Critical properties necessary for the solubility prediction
such as critical temperature, critical pressure, and critical volume were predicted for the key components fol�
lowing group contribution methods proposed by Ambrose, Lydersen, Joback and Klincewicz–Reid. Vapor
pressure of the components was also predicted based on Riedel equation. Depending on the temperature,
vapor pressure of Psoralen is higher by a factor of 10 to 2 × 1011 compared to vapor pressure of bakuchiol.