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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 1013.37 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.

The reactions of trifluoromethyl radicals with methylamine and trideuteromethylamine have been studied in the temperature range 30–160°C in order to determine the rates at which hydrogen and deuterium atoms are abstracted from the molecules. With methylamine, radical attack is favoured at the alkyl position, and substitution of deuterium for hydrogen alters the positional reactivity by an amount in accord with the zero-point energy difference. The pre-exponential factors for attack at the nitrogen site have been explained in terms of a low steric factor due to repulsion forces between the polar molecule and the radical. Arrhenius parameters (based upon a value of 1013.34 mole–1 cm3 sec–1 for the rate constant of combination of trifluoromethyl radicals ) have been measured for the reactions : CF3+CD3NH2→CF3H+CD3NH 9.94±0.22 4.4±0.4, CF3+CD3NH2→CF3D+CD2NH2 11.03±0.09 6.1±0.2, CF3+CH3NH2→CF3H+(CNH4) 10.79±0.16 4.2±0.3, CF3+CH3NH2→CF3H+CH2NH2 10.72±0.39 4.2±0.6, and have been calculated for NHCH3+CF3H→NH2CH2+CH3 9.9 18.4, (units of A, mole–1 cm3 sec–1; and E, kcal mole–1).

The reactions of trifluoromethyl radicals with methanol and trideuteromethanol have been studied in the temperature range 84–162°C in order to determine the rate at which hydrogen and deuterium atom abstraction occurs. Over this temperature range, abstraction from the hydroxyl group is slightly favoured over abstraction from the methyl group. Substitution of deuterium for hydrogen alters the positional reactivity by an amount in accord with the zero-point energy difference. Arrhenius parameters (based upon a value of 1013.34 mole–1 cm3 sec–1 of the rate constant of combination of trifluoromethyl radicals) have been measured for the reactions : [graphics omitted] and have been calculated for [graphic omitted] (units of A mole–1 cm3 sec–1 and E kcal mole–1).

The reactions of trifluoromethyl radicals, generated by the photolysis of hexafluoroacetone, with the aldehydes HCOCF3, HCOC2F5 and HCOC3F7 have been studied and the following Arrhenius parameters determined : [graphic omitted] The rate of hydrogen atom abstraction from the fluoroaldehydes at 164°C is independent of the size of the fluoroalkyl group. Direct photolysis of the aldehydes HCOCF3, HCOC2F5 and HCOC3F7 is complicated by the intramolecular elimination reactions : [graphic omitted] A value of 1.95, which is independent of temperature, has been obtained for the cross-combination of CF3 and C2F5 radicals.