IRC and Kinetic Studies of Formic Acid-Water Bihydro Concerted Exchange Reaction

The ab initio calculations have been performed on the formic acid and water to elucidate the mechanism of the hydrogen-bonding and simultaneous double proton transfer with 4-31G basis set. Full geometry optimization has been carried out both on the minimum-energy structure and on the transition-state structure. IRC path has been obtained. The results of calculations indicate that the hydrogen-bonding is a weak electrostatic interaction, being different from the covalent bond. The double proton transfer reaction of the formic acid and water proceeded in a synchroneous manner. The water molecules possess the catalytic effect. We also estimated the activated entropies and frequency factor.