β Scribed by A. Horowitz; G. Baruch
No coin nor oath required. For personal study only.
The addition reactions of CC13 radicals with cis-CzClzHz, trans-CzClzHz, and CzC13H in liquid cyclohexane-CC14 mixtures were studied between 323 and 448 K. The Arrhenius parameters of these reactions were competitively determined versus H-atom transfer from cyclohexane and addition to C2C14. The present data and the data obtained in previous liquid and gas phase studies show that the reactivities displayed in addition reactions of different radicals with chloroethylenes reflect primarily variations in activation energies rather than in A factors. The activation energies for the addition of CC13, CF3, and CH3 radicals to chloroethylenes appear, to a large extent, to be determined by the stability of the adduct radicals. Comparison of the reactivity trends in the addition reactions of chloro-and fluoro-substituted ethylenes indicates that these two electron-withdrawing substituents have a converse effect on the reactivity of electrophilic radicals. This behavior is ascribed to the strong mesomeric effect of vinylic chlorosubstituents.
π SIMILAR VOLUMES
The absolute rate constants have been measured for several gas-phase chlorine atommolecule reactions a t 25OC by resonance fluorescence. These reactions and their corre- sponding rate constants in units of cm3 mole-' sec-l are: The effects of varying the substrate pressure, total pressure, light in
Rate constants for the reactions of atomic oxygen ( 0 3 P ) with C&3F, C&IaCl,C@3Br, 1, l-CzHzFz, and I ,2-C&IzFz have been measured at 307' K using a discharge-flow system coupled to a mass spectrometer. The rate constants for these reactions are (in units of 1011cm3mole-1s-1)2.63 &0.38,5.22 =tO0.2
## Abstract The thermal decompositions of ethyl chloride, iso propyl chloride, and tertiary butyl chloride were studied in a static system in the pressure range of 0.1β300 torr. The following Arrhenius equations for the highβpressure limit were obtained: equation image The pressure dependence of