On initiation reactions of acetylene oxidation in shock tubes: A quantum mechanical and kinetic modeling study

Reaction between acetylene and molecular oxygen was analyzed using quantum mechanical calculations and kinetic modeling of acetylene oxidation in shock tubes. Calculations at the G2(B3LYP) level of theory show that the direct attack of molecular oxygen on the π bond in acetylene has a larger energy barrier than acetylene↔vinylidene isomerization, such that this isomerization followed by the reaction of vinylidene with molecular oxygen is the energetically favorable initiation reaction of acetylene oxidation. It is further shown that detailed kinetic models of acetylene oxidation including this initiation process predict well the experimental shock tube ignition delay data.