AN EMPIRICAL-METHOD TO EVALUATE THE ENHANCEMENT FACTORS OF SOLIDS IN SUPERCRITICAL GASES

A method is proposed to correlate and to predict the solubilities of p ure solids in supercritical gases. The method is based on a very simpl e thermodynamic model which links the properties of pure components to the enhancement factor E. The only parameters of pure solids required in order to evaluate their solubilities in compressed gases are densi ty, melting point and vapor pressure. According to the proposed method , each supercritical solvent deserves an 'ad hoc' rule. The reliabilit y of the method was tested on the basis of the literature data for sev eral polar and non polar solids in four supercritical solvents (ethane , CO2, CHF3 and CCLF3). Some other equilibrium data pertaining to the solubility of solid hydrocarbons and caffeine in supercritical CO2 are also considered. Further, a well known literature relation which link s the enhancement factor, E, to the solvent density, rho, is justified according the proposed thermodynamic model. (C) 1998 Elsevier Science B.V.