Reactions of Active Nitrogen with Hydrogen Bromide, Bromine, and Ethylene

Abstract

Measurement of the specific rate constant for the reaction $$\mathrm{N}+\mathrm{HBr}\to \mathrm{NH}+\mathrm{Br}$$ indicates that k is 3.8×10^—14 sec^—1 (molecules/cc)^—1 at 40°C. Attempts to obtain complete turbulence of reactants at a pressure of 0.85 mm were unsuccessful so that diffusion techniques were employed. The homogeneous flame reaction accompanying the above reaction was too weak to define the reaction zone, so calculations were based on the reaction tube diameter and the critical flow rates of reactants at which the orange flame initiated by a wall reaction involving active nitrogen and bromine was prevented. Spectra of flames obtained from the N+Br₂ and N+HBr reactions in a stirred‐flow reactor indicate that NBr is the source of the orange flame in the latter reaction. The flow rates of atomic nitrogen were calibrated by chemical titration with ethylene. A conventional diffusion flame technique was used to obtain k=1.6×10^—13 sec^—1 (molecules/cc)^—1 at 40°C for the reaction $$\mathrm{N}+{\mathrm{C}}_2{\mathrm{H}}_4\to \mathrm{HCN}+{\mathrm{CH}}_3.$$