The γ-radiolysis of cyclohexane with electron scavengers. V. C₆F₁₂ as an electron scavenger in the vapor phase

Abstract

about 90 kcal/mole of excess energy, and this is much greater than the 50 kcal/mole3 activation energy for its rearrangement to propionaldehyde. Under these circumstances it would not survive long enough to be collisionally stabilized and thus does not appear as a product in the oxygen atom -propylene system. Thus, while persistent heterogeneous reactions have frustrated the original purpose of this study of the thermal reactions of propylene oxide, a new process has been observed which may be of interest in other systems where it is not directly observable. The radiolysis of cyclohexane in the vapor phase has been examined in the presence of up t o 3 mole % perfluorocyclohexane. The results indicate that perfluorocyclohexyl radicals are produced with a yield of 2.0 G units at 3 % perfluorocyclohexane. It is concluded that these radicals are formed when the perfluorocyclohexyl anions are neutralized. The relevance of this neutralization to the liquid phase radiolysis of cyclohexane is discussed.

Reduction of Polyfluorinated Compounds

“…In this aspect, an interesting issue was to determine whether the first electron transfer and the first fluoride expulsion proceed in a stepwise (path 1a + 1b) or a concerted (path 2) mechanism as postulated for other carbon−halogen bonds, whether, in a rough approximation, the halogen atom is borne by an aromatic or an aliphatic moiety . The behavior of cyclic perfluoroalkanes could be different, since, due to the high C−F bond energy, stable radical anions can be formed in the gas phase, by electron attachment − and γ-ray irradiation, or in apolar solutions or in weakly polar solid glasses at low temperature …”

Radiolysis of 1,1-difluoroethane

“…7 The radiation chemistry of perfluoroalkanes is dominated by the breaking of carbon-fluorine bonds by mechanisms that are not yet completely elucidated. 8 The mercury photosensitized decomposition of 1,1 -difluoroethane occurs mostly through reactions of the 1,1-difluoroethyl radical. 9 1,1-Difluoroethane was chosen for this work because its lack of symmetry will lead to readily distinguishable products for many of the possible decomposition modes.…”

γ-Radiolysis of cyclohexane with electron scavengers. VII. Perfluorocyclohexane and perfluorobenzene as electron scavengers

“…The C6FllH was determined on an XE-60 column at 40 'C and C6FsH on a squalane column at 60 "C. For CsF6 solutions, cyclohexene was determined on a B,P-oxydipropionitrile -silver nitrate column, as its retention time on the normally more satisfactory 1,2,3-tris(2-cyanoethoxy)propane column was close to that of C6F6. Products were identified by retention time and by mass spectrometry (10,15).…”