A computational study on the decomposition of formic acid catalyzed by (H2O)x, x=0-3:: Comparison of the gas-phase and aqueous-phase results

The mechanisms for the water-catalyzed decomposition of formic acid in the gas phase and aqueous phase have been studied by the high-level G2M method. Water plays an important role in the reduction of activation energies on both dehydration and decarboxylation. It was found that the dehydration is the main channel in the eras phase without any water, while the decarboxylation becomes the dominant one with water catalyzed in the gas phase and aqueous phase. The kinetics has been Studied by the rnicrocanonical RRKM in the temperature range of 200-2000 K. The predicted rate constant for the (H2O)(3)-catalyzed decarboxylation in the aqueous phase is in good agreement with the experimental data. The calculated CO2/CO ratio is 200-74 between 600-700 K and 178-303 atm, which is consistent with the average ratio of 121 measured experimentally by Yu and Savage (ref 3).