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Combination and disproportionation reactions of allylic radicals with ethyl, propyl, and t-Butyl Radicals

✍ Scribed by D. L. Baulch; P. K. Chown; D. C. Montague

Publisher
John Wiley and Sons
Year
1979
Tongue
English
Weight
766 KB
Volume
11
Category
Article
ISSN
0538-8066

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✦ Synopsis

Abstract

1‐Methylallyl, 1,1‐dimethylallyl, 1,2‐dimethylallyl, 1,3‐dimethylallyl, 1,1,2‐trimethylallyl, and 1‐ethylallyl radicals have been generated in the gas phase at 20 ± 1°C by addition of H atoms, formed by Hg(6^3^P~1~) photosensitization of H~2~, to appropriate dienes. Their combination reactions with ethyl radicals have been studied and the relative reactivities of the reaction centers in each allylic radical determined. Similar measurements have been made for some combination reactions of n‐propyl, i‐propyl, and t‐butyl with 1‐methylallyl and 1,1,2‐trimethylallyl radicals. The more substituted reaction centers are found to be the less reactive. In addition the self‐combination and disproportionation of 1‐methylallyl radicals has been investigated, as has cross disproportionation of each allylic radical with ethyl. The results establish a general pattern of reactivity for these radicals, which is interpreted primarily in terms of the effects of steric interaction during reaction.

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