CORRELATION OF PARTITION-COEFFICIENTS OF ORGANIC SOLUTES BETWEEN WATER AND AN ORGANIC-SOLVENT - AN APPLICATION OF THE LINEAR SOLVATION ENERGY RELATIONSHIP

Partition coefficients of organic solutes in infinite dilution between water and 30 organic solvents at 298.15 K have been correlated by applying the linear solvation energy relationship (LSER) developed by Kamlet et al. The LSER needs five parameters to characterize a solute. Four of those parameters are determined from experimental data (densitometry and spectroscopy) while one (describing the influence of polarizability) has to be estimated. By fitting that parameter to experimental results for the partition coefficient, an essential improvement of the correlation is achieved. Partition coefficients correlated with the LSER show considerably smaller deviations from experimental data than those either predicted by UNIFAC or correlated by a recently published modification of the LSER equations by Marcus. The average absolute deviation over about 600 partition coefficients correlated with the modified LSER is 0.11 compared with 0.76 predicted with UNIFAC; the average absolute deviation over about 550 data points is 0.12 with the modified LSER and 0.34 with the modification of Marcus.