Potentiometric investigation of acid dissociation and anionic homoconjugation equilibria of substituted phenols in dimethyl sulfoxide

Abstract Standard acidity constants, K a DMSO (HA), expressed as p K a DMSO (HA) values, and anionic homoconjugation constants, K DMSO AHA − , (in the form of lg K DMSO AHA − values) have been determined for 11 substituted phenol–phenolate systems a polar protophilic aprotic solvent, dimethyl sulfoxide (DMSO) with a potentiometric titration. A linear relationship has been determined between lg K DMSO AHA − and p K a DMSO (HA). The tendency towards anionic homoconjugation in these systems increases with increasing p K a DMSO (HA) that is with declining phenol acidity. The p K a DMSO (HA) are correlated with both p K a W (HA) water and other polar non-aqeous solvents.