CORRELATION AND PREDICTION OF PARTITION-COEFFICIENTS OF ORGANIC SOLUTES BETWEEN WATER AND AN ORGANIC-SOLVENT WITH A GENERALIZED FORM OF THE LINEAR SOLVATION ENERGY RELATIONSHIP

The linear solvation energy relationship (LSER) is extended to estimate partition coefficients of organic solutes in infinite dilution between water and organic solvents at 298 K. The LSER needs five parameters to characterize a solute as well as six parameters to characterize the organic solvent/water system. To extend the applicability of the LSER, estimation rules for all parameters are desirable. In the first part of the present work rules either given in the literature or developed here are applied to determine the parameters of 101 organic substances. Predicted partition coefficients show that the estimation is reliable. Furthermore a generalized LSER equation-here called LSER36-was developed, which allows estimating infinite dilution partition coefficients of organic solutes in organic solvent/water systems at 298 K, when no individual LSER equations are known. That generalized LSER contains 36 universal constants and for each organic solvent those 5 parameters which are used to characterize the same substance as solute. Partition coefficients predicted by LSER36 agree better with experimentell data than results from other methods like UNIFAC or Marcus' recently published generalization of the LSER equation.