Predictions of log P for aromatic compounds

Abstract

In a previous paper it has been found that Hammett’s parameter σ(X)_p is not very useful as a measure of electronic effects. The equation log P(XC₆H₄Y) = log P(C₆H₆) + π(X) + π(Y) + σ(X) × ρ_p(Y) + σ(Y) × ρ_p(X) deduced for the calculation of log P values for aromatic compounds has therefore been revised. Good results are obtained when σ_p(X) is replaced by the parameter σ_p(X)_p specifically designed for use in distribution processes. A number of π(X), π(Y), and ρ_p(Y) values are given which, together with the σ′_m(X) values, can be used to calculate log P values.