Matrix Infrared Spectra and Photolysis and Pyrolysis of Isotopic Secondary Ozonides of Ethylene

Article abstract of DOI:10.1021/j100213a019

The secondary ozonide of ethylene (SOZ) has been prepared in six isotopic modifications by reacting ozone and ethylene in CF3Cl near -150 deg C.The SOZ vibrations are characterized by 18O, 13C, and D isotopic shifts from matrix infrared spectra.Photolysis and pyrolysis of the SOZ is proposed to proceed via excited hydroxymethyl formate (HMF^*).Under the conditions of pyrolysis, this activated species decomposes completely to formic acid and formaldehyde, but matrix photolysis of SOZ leads to quenching of HMF^* and trapping of the ground-state molecule.An open chain trans and a hydrogen-bonded cis conformer of HMF are observed; photoexcitation decomposes the former to formic anhydride (FAN) and the latter to a specific formaldehyde-formic acid dimer (F/A).The dimer F/A is also observed following pyrolysis of SOZ and codeposition of formic acid and formaldehyde.The origin of CO2 produced on SOZ pyrolysis and of CO2, CO, and H2O produced on SOZ photolysis is discussed.A brief comparison of results from ethylene-ozone gas-phase studies with matrix photolysis of SOZ suggests that ground- or excited-state SOZ may play an important role in the gas-phase ethylene-ozone reaction, even though it is rarely detected.