THE ETHENE-OZONE REACTION IN THE GAS-PHASE

The ethene-ozone reaction was investigated in a 570 L spherical glass reactor at atmospheric pressure, using long-path FTIR spectroscopy for detection of the individual products. Experiments were performed in t he presence of hydroxy and carbonyl compounds to identify the reaction s of the Criegee intermediate CH2OO formed in ethene ozonolysis. Using C-13-labeled HCHO, this reaction was found to proceed via an unstable cyclic adduct which decays to the detected products HCHO, HCOOH and C O. [CH2OO + HCHO --> HCHO + HCOOH (eq 13); CH2OO + HCHO --> HCHO + CO + H2O (eq 14a); CH2OO + HCHO --> HCHO + HCO + OH (eq 14b)] The relativ e rates of the reactions of CH2OO with HCOOH and HCHO were determined from the product analysis. In addition, evidence was found that the re action of CH3CHO with the CH2OO intermediate does not exclusively prod uce secondary propene ozonide, but also HCHO and CO2. The results of t his study have been combined with data from previous investigations to give a complete description of the gas phase ozonolysis of ethene and are discussed in comparison with ozonolysis reactions occurring in th e liquid phase.