COMPUTATIONAL DETERMINATION OF THE KINETICS, MECHANISMS AND THERMODYNAMICS OF THE DECOMPOSITION REACTION OF PYRUVIC ACID

Abstract

The gas phase decarboxylation of Pyruvic acid (CH₃COCOOH) yielded Hydroxyethylidene (CH₃COH). The kinetics, mechanism, and thermodynamics studies of pyrolysis of pyruvic acid at 623k was studied using semi-empirical(PM3) and DFT with B3LYP/6-31G* basis set. The reaction was found to be first order rate equation. The temperature dependence of the rate coefficients is given by the following Arrhenius equation: log A(S^-1) with PM3 = 12.60 and DFT/B3LYP at 6-31G* = 13.05. The calculation values for the energy of activation, entropy, Gibb’s free energy and enthalpy of activation were predicted. The theoretical calculations suggest a molecular mechanism involving a concerted polar five membered cyclic transition state which involves O₃-H₃ and C₂-C₃ bond breaking and O₁-H₃ bond formed.