The Effects of Substituents on the pK_α, Values of "meta"-Substituted 1- and 2-Naphthols

Abstract

pK_a values (H₂O at 25°C) have been measured for 3-substituted 1-naphthols and 4-substituted 2-naphthols and the results show that the behaviour of these compounds is similar to that of the equivalent naphthylamines. ΔpK_a values satisfy equations of the type: ΔpK_a = ρ_Iσ_I + ρ_Rσ_R, where σ_I and σ_R are inductive and mesomeric constants applying to meta-substituents. Reaction constants ρ_I and ρ_M are interpreted in terms of the energy terms involved and can be correlated with the a-electron distributions in the molecular species concerned.