Simultaneous determination of partition coefficients and acidity constants of chlorinated phenols and gualacols by gas chromatography

The partition coefficients, P, in the n-octanol/water system and the acidity constants, K_a, of 15 chlorinated phenols and guaiacols at 20° were simultaneously determined by investigating the pH dependence of the apparent partition coefficients, P_a. For determining P_a, the relative responses of individual phenols and guaiacols in the aqueous phase after equilibration were measured by glass-capillary gas chromatography with electron-capture detection and compared with those in the octanol phase before partition. Curvefitting, linear regression, and non-linear regression were used for treating the partition data. The values of pK_a and log P were compared with the values which could be found in the literature, and are discussed in relation to their affinity to methanol/water and acetonitrile/water mixtures.