A Gasphase Kinetic Investigation of the System F + HNO₃ and the Determination of Absolute Rate Constants for the Reaction of the NO₃ Radical with CH₃SH, 2‐Methylpropene, 1,3‐Butadiene and 2,3‐Dimethyl‐2‐Butene

The reaction of HNO 3 with atomic fluorine (1) has been studied in a discharge‐flow system at 298 K. Mass spectrometric detection with single ion counting was employed. The rate constant for the primary reaction (1) at 298 K. has been determined from the rate of HF and NO, formation under conditions [HNO 3 ] ≫ [F] 0 and the rate of HNO 3 ‐removal under conditions [F] ≫ [HNO 3 ] 0 From the patterns of growth and decay of the primary product NO 3 and the secondary product FO under various ratios of the initial concentrations of the reactants, the rate constants of the following secondary reactions have been determined: Further, the rate constants for the reactions of NO 3 with CH 3 SH, 2‐methylpropene, 1,3‐butadiene and 2,3‐dimethyl‐2‐butene at 298 K have been determined by introducing these reactants into the flow system and measuring their consumption under pseudo‐first‐order conditions. The values of the rate constants obtained are 7.7 ± 0.5, 3.3 ± 0.5, 1.7 ± 0.3 and 384 ± 38 in units of 10 −13 cm 5 s −1 respectively. A comparison is made between the values determined in this work and those reported in the literature.