Abstract Thermodynamic dissociation constants in various water-organic solvent mixtures are given for benzylammonium, benzyldialkylammonium, and (2-phenylethyl) ammonium ions. Deviations from the Hammett equation (Eqn. 1) are similar to those observed for carboxylic acids, but of opposite sign. The extended Hammett equation (Eqn. 3), containing the hydrophobic constant, π, yields good correlations. Derived secondary normal sigma ...
