Mass spectrometry study of the pyrolysis of perfluoroolefin oxides

The pyrolysis of perfluoroolefin oxides has been studied by gas chromatography/mass spectrometry at 400–700°C, in a current of He (1∶10 dilution, contact time 1 sec). For oxides containing a terminal CF2 group, the sole degradation route is through the elimination of difluorocarbene. Pyrolysis of symmetrical disubstituted oxides results in the elimination of a perfluoroalkylfluorocarbene, which subsequently isomerizes to the corresponding perfluoroolefin. In the pyrolysis of unsymmetric disubstituted oxides the elimination of perfluoroalkylfluorocarbenes occurs by both of the possible routes. Trisubstituted oxides eliminate bis-perfluoroalkylcarbenes. The decomposition of tetrasubstituted oxides proceeds along several directions concurrently.