D. James, E. Steacie
Mar 25, 1958
Citations
0
Influential Citations
6
Citations
Journal
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
Abstract
The kinetic study of the addition of the ethyl radical to the multiple bond has revealed the effect of various structural factors upon molecular reactivity. Hydrocarbons were selected as representative of the classes: 1-alkyne, 1-alkene and 2-methyl 1-alkene. Values for the energy of activation (E7 ‒ ½E2) are distinct at 8·8 ± 0·4, 7·0 ± 0·2 and 5·7 ± 0·9 kcal mole-1 respectively for these classes. The value of the frequency factor is sensitive to any structural feature able to restrict the access of the ethyl radical to the double bond. The absolute value for the addition rate constant for 1-heptene is k7 = 3·2 × 10-13exp (‒ 8000 ± 700)/RT cm3 mol.-1 s-1. A quantitative explanation is proposed for the failure of radical catalysts to polymerize 1-heptene or 1-heptyne. A number of physical models for the addition reaction are examined in relation to the results of this paper.