KINETICS OF REACTION OF TRIFLUOROMETHYL RADICALS WITH AMMONIA

The gas-phase reaction of trifluoromethyl radicals with ammonia has been studied over the temperature range 81-252° The trifluoromethyl radicals were generated by photolysis of CF3I. The rate constant for the reaction CF3 + NH3 → CF3H + NH2 was found to be k = (3.3 ± 1.3) × 1010 exp{(-8300 ± 200)/RT} in units of cm3 mol-1 sec-1. A comparison of CF3 and CH3 reactions with various polar and nonpolar molecules is presented The difference in activation energy for these two radicals is consistently lower with polar molecules than with nonpolar substrates. However, there appears to be no simple systematic trend between the activation energy difference and the polarity of the substrate.