Relative partition coefficients for organic solutes from fluid simulations

A procedure is noted for obtaining the difference in partition coefficients (log P) for two solutes between two solvents. Fluid simulations are required in which one solute is mutated to the other in both solvents, and the changes in free energies of solvation are computed. The method is illustrated for eight pairs of organic solutes partitioning between water and chloroform. Monte Carlo statistical mechanics simulations are used with statistical perturbation theory to calculate the requisite free energy changes