Disproportionation‐to‐combination ratios for cyclohexyl‐ h 11 and ‐ d 11 radicals in the gas phase as determined by the radiolysis of water vapor–cyclohexane mixtures

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   d H / k   c Hfor c ‐C 6 H 11 radicals could be determined as 0.56 ± 0.01 from the ratio of cyclohexene to bicyclohexyl yield. By using c ‐C 6 D 12 , the ratio k   d D / k   c Dfor c ‐C 6 D 11 radicals is found to be 0.38 ± 0.01. Comparison of the reactivity pattern of C 6 H 11 and C 6 D 11 radicals leads to ( k   d H )/( k   c H )/( k   d D / k   c D ) = 1.47 ± 0.02. The corresponding values for the reactions of c ‐C 6 H 11 with c ‐C 6 D 11 were also determined.