Density functional theory response to the calculations of p Ka values of some carboxylic acids in aqueous solution

Abstract

The acidity of 28 carboxylic acids in aqueous solution has been calculated using density functional theory. The calculations are carried out at the B3LYP level with inclusion of entropic and thermochemical correction to yield free energies of dissociations. The Polarized Continuum Model (PCM) is used to describe the solvent. The model provides p K a values in better agreement with experimental data than those obtained at the level of Hartree–Fock using 6-31G(d,p) basis set. The role of relaxation energies in improving the results has been investigated.