γ-Radiolysis of cyclohexane with electron scavengers. III. Perfluorocarbons as electron scavengers

Abstract

The room temperature, liquid phase radiolysis of cyclohexane in the presence of three solutes: perfluorocyclohexane (PCH), perfluoromethylcyclohexane (PMCH), and perfiuorocyclobutane (PCB) has been examined. All decrease the hydrogen yield from 5.6 to 2.6 G units by capturing electrons. However, with PMCH and PCB the yields of cyclohexene and bicyclohexyl are not decreased as much as the hydrogen yield and with PCH, dimer and olefin yields are increased. Furthermore, large yields of monohydrofluorocarbon (e.g. undecafluorocyclohexane) are produced, indicating that a carbon-fluorine bond has been broken. It is concluded that electron capture by these fluorocarbon compounds causes dissociation; possible mechanisms are discussed, but it was not possible to reach a clear conclusion on the basis of our results.The radiolysis of homogeneous solid solutions of these solutes at 77 "K has also been studied, but only PMCH was studied in detail. Under these conditions there is no evidence for dissociative electron capture and apparently the combination of solute anion and hydrocarbon cation on warming does not lead to bond breaking.

The effect of electron, positive ion, and hydrogen atom scavengers on the yields of atomic and molecular hydrogen in the radiolysis of liquid cyclohexane

“…laboratories, which are also given in Figure 1, show a form for the concentration dependence which is very similar to that given by the halides. These latter results are, in general, similar to those reported by other workers2, [16][17][18][19][20][21] though in certain cases slight differences exist in the values given for a particular solute concentration. In fact the literature values are not always internally consistent (e.g., hydrogen yields from 2.82 to 3.616 have been reported for 0.1 M N20 solutions in cyclohexane).…”

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

“…The results in Fig. 2 show that the hydrogen yield is reduced as efficiently as with C6F12 (10). In contrast to results with C6FI2 (lo), cyclohexene, and dicyclohexyl are reduced proportionately more than the hydrogen yield, so that there is a hydrogen surplus of about 1.9 G units at 0.05 M C6F6 and 1 G unit at 0.3 M C6F6.…”

“…have been described (10). Large yields of C6F1 ,H were noted and were ascribed to the effects of electron capture by C6Fl,.…”

“…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).…”

Radiolysis of trifluoroidomethane in the gas phase

“…14 The use of fluorocarbons as electron scavengers has also received attention. 15,16 These studies have in part been stimulated by the high thermal stability of such compounds. If this thermal stability was matched by their radiolytic stability they would constitute a group of compounds of considerable interest in nuclear technology.…”