Absolute rate constants for reactions of free radicals in the high‐temperature photolysis of formamide vapor. II. Amino radicals

Abstract

The rotating‐sector method has been applied to the photoinitiated radical‐chain decomposition of formamide at 300°C to measure the rate constant for the bimolecular disappearance of NH₂ radicals. The decomposition is propagated by the reactions (1) (2) Conditions were chosen so that reaction (1) was rate controlling and NH₂ the terminating radical. A flow system was employed with C₂F₆ as a carrier gas at a pressure of 300 Tort, and the chain reaction was initiated by the photolysis of either formamide or NH₃. A value of 4.7(±2.0) × 10¹⁰ (M ·sec)⁻¹ was estimated for the termination reaction (3) and a value of 8.4 × 10⁶ (M ·sec)⁻¹ for reaction (1) in the same system, both at 300°C.