Mechanism of the Ozonolysis of Ethylene-Acetaldehyde Mixtures

Article abstract of DOI:10.1021/ja00322a025

Ethylene-1,1-d2 was ozonized in the presence of acetaldehyde.The yields of ethylene ozonide-d0, -d2, and -d4 and propylene ozonide-d0, and -d2 were determined by proton NMR, microwave spectroscopy, and manometric measurements.The ratio of propylene ozonide-d0/propylene ozonide-d2 decreased as the concentration of acetaldehyde increased.This indicates that an inverse kinetic secondary isotope effect is associated with the recombination reactions of the carbonyl oxide (Criegee intermediate).A kinetic model was employed to describe the Criegee reaction mechanism and to estimate the final product ratios.This model resulted in quantitative estimates of the KSIE for the carbonyl oxide, the relative dipolarophilicity of formaldehyde and acetaldehyde, and the cage effect upon primary ozonide decomposition.The inverse KSIE for the carbonyl oxide and formaldehyde in their recombination reaction is consistent with a concerted process.