Dissociation constants of neutral and charged acids in methyl alcohol. The acid strength resolution Original Research Article

A comprehensive and critical compendium of the pKa values in methanol of phenol derivatives, carboxylic acids, both aliphatic and aromatic acid derivatives, protonated amines and nitrogen-protonated heterocyclic bases is given in this paper. Values have been correlated with those obtained in aqueous solution and linear relationships for each series of compounds have been established. The proposed equations can be used to estimate accurately the dissociation constant value in water or in methanol of any compound of the mentioned chemical families, from the experimental value in methanol or in water, respectively. The acid strength resolution in the alcohol with reference to water is discussed according to the chemical structure of the compounds involved and to the solvating properties of methanol and water.