The reaction of 2,5‐dimethylpyrrole with O 2 ( a 1 Δ g ) in the gas phase

The chemical reaction of 2,5‐dimethylpyrrole (C 6 H 9 N) with O 2 ( 1 Δ g )was studied in the gas phase in an isothermal flow reactor at room temperature and low pressures. The C 6 H 9 N concentration profiles were studied under pseudo‐first order conditions [C 6 H 9 N] ∘ ≪ [O 2 ( 1 Δ g )] with mass‐spectrometric detection of C 6 H 9 N. O 2 ( 1 Δ g ) was produced either in a microwave discharge or in a chemical reaction. The value for the rate constant:\documentclass{article}\pagestyle{empty}\begin{document}$$ k_{1c} (298{\rm K)} = (1.0 \pm 0.3)10^{11} {\rm cm}^{\rm 3} \cdot {\rm mol}^{ - {\rm 1}} \cdot {\rm s}^{ - {\rm 1}} $$\end{document}was measured. The rate constant is compared to the value obtained for the quenching process. The primary product C 6 H 9 NO 2 was detected by mass spectrometry and the reaction mechanism is proposed. The possibility of using this reaction as a gas phase titration reaction for O 2 ( 1 Δ g ) is discussed.