ChemInform Abstract: ABSOLUTE RATE CONSTANTS FOR THE REACTIONS BETWEEN AMINO AND ALKYL RADICALS AT 298 K

Abstract

The absolute rate constants for the reactions of NH2 radicals with ethyl, isopropyl, and t-butyl radicals have been measured at 298 K, using a flash photolysis–laser resonance absorption method. Radicals were generated by flashing ammonia in the presence of an olefin. A new measurement of the NH2 extinction coefficient and oscillator strength at 597.73 nm was performed. The decay curves were simulated by adjusting the rate constants of both the reaction of NH2 with the alkyl radical and the mutual interactions of alkyl radicals. The results are k(NH2 + alkyl) = 2.5 (±0.5), 2.0 (±0.4), and 2.5 (±0.5) × 1010M−1·s−1 for ethyl, isopropyl, and t-butyl radicals, respectively. The best simulations were obtained when taking k(alkyl + alkyl) = 1.2, 0.6, and 0.65 × 1010M−1·s−1 for ethyl, isopropyl, and t-butyl radicals, respectively, in good agreement with literature values.