Prediction of soil adsorption coefficient Koc for phenylthio, phenyisulfinyl and phenylsulfonyl acetates

Soil adsorption coefficients (Koc) have been measured by the batch equilibrium method for 25 phenyhhio, phenylsulfinyl and phenylsulfonyl acetates. Their Koc values were correlated with their HPLC capacity factors. The determination of Koc via HPLC capacity factor has been studied, including the effect of mobile phase composition on the correlation between Log Koc and Log k′. Partial molecular connectivity indices (MCls) have been calculated for these compounds and used to descnbed their Log Koc values. Results demonstrate that while HPLC capacity factors (k′), molecular connectivity indices (MCIs) and octanol/water partition coefficients (Kow) can correlate with Koc significantly, the k′w, a theoretical capacity factor which has been obtained by extrapolation of retention data in a binary solvent system to pure water eluent, has the most powerful ability in prediction of Koc for these studied compounds.