Mass spectrometric study of the vacuum pyrolysis of perfluorohexene-2 and determination of the ionization potential of the perfluoro-2-buten-4-yl radical

The ionization potential (IP) of the perfluoro-2-buten-4-yl radical, generated at 950C and 1·10⁵ torr by vacuum pyrolysis of perfluorohexene-2, was found to be 10.3 ± 0.1 eV by the electron impact method. This value is close to the IP of the perfluoro radicals n-C₃F₇ (10.06 ± 0.1 eV) and i-C₃F₇ (10.5 ± 0.1 eV); however, it is 1.8 eV higher than that of the perfluoroallyl radical, possibly because of the weak delocalization of the unpaired electron. At pyrolysis temperatures above 800C, the perfluoro-2-buten-4-yl radical decomposed to the tetrafluoroallene and trifluoromethyl radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1220–1223, May, 1991.