RELATIONSHIPS BETWEEN SOLUTE MOLECULAR-PROPERTIES AND SOLUBILITY IN SUPERCRITICAL CO2

For 21 organic compounds, we have investigated the dependence of solubility in supercritical C02 upon several properties of the solute molecules, which were calculated at the ab initio SCF STO-5G*//STO-3G* level. Good double-variable linear regressions were found that relate solubility to (a) the total variance of the electrostatic potential on the molecular surface and (b) the molecular volume. Solubility varies inversely with the variance of the surface potential, consistent with solute-solute interactions dominating over solute-solvent interactions in determining solubility in low-density supercritical solutions.