Quantum-Chemical Calculations of the Primary Reactions of Thermal Decomposition of Cyclopentadienone

Abstract

The geometric structures, vibration frequencies, and energies of the reactants, products, and transition states in the decomposition of C₅H₄O were evaluated by quantum chemical calculations using the CCSD(T)-F12/vtz-f12B method. The calculated energy barriers for the two most probable pyrolysis pathways of C₅H₄O, equal to 96.3 and 96.5 kcal/mol, respectively, are evidence that the pyrolysis proceeds at a high temperature, and the most likely reaction products are vinylacetylene and carbon monoxide. It is shown that the formation of products such as cyclobutadiene, acetylene, and propadienal can be explained by the occurrence of an energetically favorable pathway.