Reactions of radicals containing fluorine. Part 3.—Hydrogen and deuterium atom abstraction from dimethylamine, dimethylamine-d, trimethylamine and ethyleneimine

Abstract

The reactions of trifluoromethyl radicals with dimethylamine, dimethylamine-d, trimethylamine and ethyleneimine have been studied in the temperature range 27–161°C. Arrhenius parameters (based upon a value of 10^13.37 mole^–1 cm³ sec^–1 for the velocity constant for the combination of trifluoromethyl radicals) have been obtained for the reactions : [graphic omitted] With dimethylamine, radical attack is favoured, on a “per-atom basis,” at the nitrogen atom but the difference in reactivities of the C—H and N—H bonds is much less marked than with methyl radicals. Assuming a zero secondary isotope effect, substitution of D for H in dimethylamine alters the reactivity of the amino group by an amount in accord with zero-point-energy difference.