Acidity functions and the protonation of weak bases. Part VI. The amide acidity function: its extension and application to N-oxides

Abstract

The protonation of pyridine 1-oxides of low basicity in aqueous sulphuric acid solutions is correlated by the amide acidity function rather than the Hammett acidity function. The HA-scale has been extended by measurements of the second protonation of phenazine 5,10-dioxide.