Radiolysis of Methylcyclohexane. II. Liquid Phase Inhibition by Benzene

Abstract

The effect of benzene on the radiolysis of liquid methylcyclohexane (MCH) has been studied over the benzene concentration range from 0.25 to 100 mole %. The dominant effect of benzene at low concentrations appears to be one of hydrogen atom scavenging. At higher concentrations, the transfer of energy (excitation or ionization) from activated MCH to benzene also becomes important. As in the liquid cyclohexane system, there seem to be two major reactive species in γ‐irradiated MCH. One species, C₇H₁₄′, decomposes to produce ``cold'' hydrogen atoms that can be scavenged by benzene. The other species, C₇H₁₄″ or C₇H₁₄⁺, produces hydrogen by a mechanism that is not subject to atom scavenging but which can be inhibited by an energy transfer process. The 100‐ev yields of the activated species in pure MCH are G(C₇H₁₄′) = 1.8±0.3 and G(C₇H₁₄″) = 3.0∓0.3. These compare with the cyclohexane yields G(C₆H₁₂′) = 2.4±0.3 and G(C₆H₁₂″) = 3.0∓0.3. Reaction mechanisms have been proposed and tested against the experimental data.