Abstract'The gamma-radiation-induced free-radical chain reactions in liquid CC14-C&L-c-CsHly mixtures were studied in the temperature range of 363-448°K. T h e main products in this system are chloroform, hexachloropropene and chlorocyclohexane. These products are formed via reactions (1)- (5): (1) From this result and the previously determined Arrhenius parameters of reaction ( l ) , ti? is I'iiund t o he given by log k ? (l/mol-sec) = 7.58 -9.?9//1

No abstract

The kinetics of the gamma-radiation induced free-radical chain reaction in solutions of carbon tetrachloride in cyclohexane (RH) has been investigated in the temperature range of 303-383'K.Trichloromethyl radicals were produced by the reaction of radiolytically generated cyclohexyl radicals with carbon tetrachloride. The kinetics of the following reactions were investigated:The following rate expression was obtained: log k 3 / ( k 4 ) l l Z (cm3~2/mo1e1~2~sec1~2) = 4.78 f 0.08 -(8.81 f 0.12)/01The error limits are the standard deviation from the least mean square Arrhenius plots. Effects of phase on the kinetics of reactions (3) and (4) are considered.

No abstract

The y-radiation-induced chain reactions in liquid solution of silane (R',SiH) in CC14-c-C6H12(RH) mixtures were investigated over the temperature range 303-423 K for R' = Me and 335-423 K for R' = Et. In both systems the main products are R',SiCl, CHCl,, and RC1. By kinetic analyses of product distribution, the rate constants of hydrogen abstraction from the two silanes by CCl, radicals were competitively determined vs. hydrogen abstiraction from cyclohexane. The relative rate constants combined with the known Arrhenius parameters of t h e reference systems gave the following Arrhenius parameters for the reaction CC13 + Rt3SiH -CHC13 + R',Si: log A4 (L mol-' s-l) = 8.49 and E4 = 8.70 kcal mol-l when R' = Me, and log A4 = 8.62 and E4 = 8.06 when R' = Et. These results indicate that alkyl-substituted silanes are considerably more reactive than C13SiH in the H-atom transfer reactions with CCl, radicals. This observation is rationalized in terms of the polar effects of the alkyl substituents.