Analysis and prediction of hydrophobicity parameters of substituted acetanilides, benzamides and related aromatic compounds

Abstract

AbstractThe partition coefficient P in the 1‐octanol/water system was analyzed for a great number of multisubstituted benzenes of ecotoxicological importance consisting of acetanilides, benzamides, nitrobenzenes, and anisoles having various substitution patterns in terms of the Δ log P (log P – log P[unsubstituted benzene]) quantitatively with free energy‐related physicochemical substituent parameters. The analyses showed that the stereoelectronic effects of ortho, meta, and para substituents on the relative solvation of individual polar groups capable of hydrogen bonding with the partitioning solvents are very important in determining the variations in the log P value. The effects were additive in the set of complicated multisubstituted benzenes, leading to a correlation equation represented by a linear combination of terms of hydrophobic, electronic, and steric parameters summed up over substituents. It was suggested that the procedure be extended to analyze and predict the log P value of any multiply substituted benzenes.