A discussion of the pKBH+ values of weak bases as derived by different calculation methods

Abstract

The Hammett acidity function method (HAFM), the excess acidity function method (EAM), and the Bunnett–Olsen method (BOM) have been compared in order to rationalize the differences observed between pK_BH⁺ values estimated by each classical method. The results point out that on the basis of (i) the strength and kind of bases analysed and (ii) the aqueous acid solution used to determine the ionization ratios C_BH⁺/C_B=I, it is possible to predict when the three methods give similar results and when they give different pK_BH⁺ values.