First-Generation Products of <i>Trans</i>-2-Hexenal Ozonolyis: A New Look at the Mechanism

The ozonolysis reaction of <i>trans</i>-2-hexenal was studied theoretically on the basis of highly accurate CCSD(T)-F12b/AVTZ energy values obtained in M06-2X/AVTZ preoptimized nuclear configurations. The kinetics was modeled with the help of the master equation solver MESMER. Apart from the expected stable oxidation products 1-butanal (17%) and glyoxal (35%), a secondary ozonide is formed on the glyoxal channel, which is the principal first-generation product (49%). It is further shown that glyoxal is created on two competing pathways, one of which leads to simultaneous production of the ester propylformate (18%). The inclusion of all of these mechanisms explains the experimental findings and identifies for the first time the origin of the experimental carbon deficit.