USING QUANTUM-CHEMISTRY TO PREDICT SOLUBILIZATION IN DETERGENT MICELLES

Experimental K-s, values for the solubilization of 66 non-ionic solute s in micelles of the anionic detergent sodium dodecyl sulfate can be r eproduced using quantum chemical surrogate parameters, the calculation of which requires only a knowledge of the solute molecular structure. The parameters evaluated include the solute molar volume (V-x), the s olute HOMO and LUMO energies, the magnitudes of the charges of the mos t positive hydrogen and most negative atom of the molecule (q(+) and \ q(-)\ respectively), the molecular dipole moment and the solute ''dipo larity'' (the molecular polarizability divided by V-x). The resultant linear solvation free energy relationship (LSER) based on these surrog ate parameters (log K-s = -0.487 + 1.27q(+) - 3.76\q(-)\ + 2.97V(x)) i s chemically reasonable and consistent with the LSER for micellar solu bilization based on experimentally-derived solute parameters. The use of quantum chemical parameters to develop LSERs should thus prove to b e a convenient approach for predicting solubilities in organized media from solute molecular structure. (C) 1997 Elsevier Science B.V.