Radiolysis in the adsorbed state. I. Cyclohexane adsorbed on silica gel

Abstract

Isotopic labelling techniques have been used to study the Co-60 γ-radiolysis of cyclohexane adsorbed at low coverage on silica gel. It has been shown that some of the energy absorbed in the silica gel is able to cause decomposition of the hydrocarbon, but it has also been shown that the silica gel takes part in the system as a chemical reactant. The effect on the radiolysis of changing the chemical nature of the gel by varying the water content was studied and it is shown that the radiolysis is quite different over gels with low and high water content. These changes are ascribed to the replacement of silanol groups by siloxane groups, with the removal of chemisorbed water.The effect of the additives N2O and SF6 was studied in an attempt to determine how much of the reactivity was transferred from the solid by an ionic mechanism. It was concluded that over gels with a high water content more than one half of the reactivity was ionic in nature, whereas over gels with low water content much less was ionic.