Disproportionation‐to‐combination ratios for cyclohexyl‐h₁₁ and ‐d₁₁ radicals in the gas phase as determined by the radiolysis of water vapor–cyclohexane mixtures

Abstract

In the radiolysis of water vapor containing small concentrations of cyclohexane, the principal products which account for about 98% of all end products are found to be hydrogen, cyclohexene, and bicyclohexyl. Cyclohexene and bicyclohexyl yields were determined over a range of temperatures (70-200°C), total pressures (50-2400 torr), and total doses (0.15-2.0 Mrad). The disproportionation-combination ratio k;/kP for c -C~H I I radicals could be determined as 0.56 f 0.01 from the ratio of cyclohexene to bicyclohexyl yield. By using c-CgD12, the ratio kflkf for c-CgDII radicals is found to be 0.38 f 0.01. Comparison of the reactivity pattern of CgHll and CgDll radicals leads to (k;/kF)/(kf/kF) = 1.47 f 0.02. The corresponding values for the reactions of c-C~H11 with c-CgD11 were also determined.

Self‐ and cross‐disproportionation‐to‐combination rations for cyclopentyl and cyclohexyl radicals and their deuterated analogues

“…The effects of temperature, pressure, and dose observed in the present work are similar to those previously reported, where they weire discussed at length [12]. Neither isomerization nor pyrolysis of the cyclopentyl a Tirrad = 170OC; V = 65 mL; P = 470 torr; concentration of cyclopentane + cyclohexane…”

“…In order to ascertain the reproducibility of our previous work [12], we have redetermined the yields of cyclohexene and bicyclohexyl from water-vapor-cyclohexane mixtures as a function of dose. The agreement with our previous results is very satisfactory.…”

“…The sum of the G values for other minor hydrocarbon products does not exceed 0.2 at cyclopentane concentrations lower than 2 mol-9%. However, contribution by direct decomposition of the additive is getting more important with increasing concentration of the additive, because the radiation energy ab- In order to ascertain the reproducibility of our previous work [12], we have redetermined the yields of cyclohexene and bicyclohexyl from water-vapor-cyclohexane mixtures as a function of dose. The agreement with our previous results is very satisfactory.…”

Physicochemical Properties of Deuterated Compounds. 8th Communication. The kinetic isotope effect for the reaction of hydrogen atoms with methylcyclohexane and perdeuteromethylcyclohexane in the gas phase

“…Furthermore, the material balance expected from the reaction scheme, G(hydrogen) = G (cyclohexene) + G(bicyclohexyl), was confirmed [25] [26]. With methylcyclohexane, the radical R produced in Reactions 2 and 4 represents five isomeric radical species, i.e.…”

“…Reaction Mechanism. Since the mechanism for the radiolysis of water vapour has been described in detail in [21] [24] [25], a brief account of them will be given here. Excitation and ionisation of water vapour by radiation lead to the formation of H20*, H,O+; and e-in the initial steps.…”