Effect of an Electron-scavenging Solute on the Radiolysis of Cyclohexane

Abstract

ALTHOUGH a considerable body of evidence exists indicating that solutes of a radical scavenging nature depress the yields of the principal products (hydrogen, cyclohexene, dicyclohexyl) from the gamma radiolysis of cyclohexane¹, the effect of electron scavenging solutes is less well characterized. Scholes and Simic² have shown that in the presence of nitrous oxide, a powerful electron but feeble hydrogen atom scavenger, the hydrogen yield is decreased by a factor of two (G(H₂) = 2.78 at [N₂O] = 100 mM), G(N₂) being 3.75 at the same concentration. In the course of similar investigations on carefully de-aerated cyclohexane we have observed a marked increase in the gamma radiolysis yield of dicyclohexyl (see Table 1). The measured yields are independent of dose rate in the range 0.2–2.5 M rads/h and independent of nitrous oxide concentration in the range 15–130 mM. Impoverishment of nitrous oxide in the liquid phase was avoided by the use of low total doses (< 0.5 M rad) and by performing irradiations on samples in which gas–liquid equilibration was facilitated by a high surface to volume ratio of the liquid.