The Effect of Chloromethanes on Hydrogen Formation in the Radiolysis of Methylcyclohexane and 3-Methylpentane at −196°C

Abstract

Abstract The effect of chloromethanes (CH2Cl2, CHCl3 and CCl4) on hydrogen formation from γ-irradiated methylcyclohexane (MCH) and 3-methylpentane (3MP) at −196°C was investigated. It was found that the decrease in hydrogen yield by the presence of CH2Cl2 was almost the same as that caused by an electron scavenger such as N2O, n-butyl chloride, SF6 or iodobenzene, but the hydrogen yield was much lower in the presence of CHCl3 or CCl4 than other electron scavengers. Although the yield of CCl3. radicals formed from dissociative electron attachment to CCl4 in CCl4-MCH systems was ∼1.4G, the decrease in hydrogen yield was ∼3G. A similar result was obtained for CHCl3-MCH systems. Thus we have ascribed the effect of CH2Cl2 on hydrogen formation to electron scavenging and that of CHCl2 or CCl4 to excitation transfer as well as electron scavenging. ESR studies on radical formation from these systems also support the above interpretation.