Polyfluoroalkyl derivatives of nitrogen. Part XXXIV. The kinetics of the gas-phase thermal decomposition of trifluoroacetyl nitrite. The slow reaction

Abstract

The kinetics of the gas-phase thermal decomposition of trifluoroacetyl nitrite have been studied over the temperature range 119–172°C. The formation of CO₂ is quantitative and the decomposition is first order in reactant. The rate constant for the decomposition: log k(s^–1)=(14·26 ± 0·23)–(33,800 ± 440)/4·576 T is independent of the initial pressure of reactant from 7·7–22·2 Torr and independent of the surface: volume ratio of the reaction vessel; it is also unaffected by the presence of nitric oxide, propene, trifluoronitrosomethane, and carbon dioxide. The formation of trifluoronitrosomethane is inhibited by propene and by any trifluoronitrosomethane initially present, but is enhanced by the presence of nitric oxide. It is concluded that the reaction occurs by a homogeneous radical non-chain process, in which the initial rate-determining step is the cleavage of the O–NO bond to produce nitric oxide and the trifluoroacetoxyl radical.