Gas‐phase thermolysis of allyl propargyl amine, allyl cyanomethyl propargyl amine, allyl propargyl 2‐thiapropyl amine, and allyl methanesulfonyl propargyl amine

The title amines have been pyrolyzed in a stirred‐flow reactor, at temperatures of 360–500°C, pressures of 7–16 torr, and residence times of 0.5–2.9 s, using toluene as carrier gas. The reaction products were allene, propene, and the corresponding imines. The ratio allene:propene varied in the range 6.7–1.6. The amines with CH 2 CN and SO 2 CH 3 substituents also formed HCN and SO 2 . These appear to arise from complex free radical decomposition of the imine product. The first‐order rate coefficients for the production of allene plus propene followed the Arrhenius equations: Allyl propargl amine:\documentclass{article}\pagestyle{empty}\begin{document}$$ k\left({{\rm s}^{- 1}} \right) = 10^{10.07 \pm 0.31} \exp \left({- 133 \pm 4{\rm kj/mol\,}RT} \right) $$\end{document}Allyl cyanomethyl propargyl amine:\documentclass{article}\pagestyle{empty}\begin{document}$$ k\left({{\rm s}^{- 1}} \right) = 10^{10.73 \pm 0.30} \exp \left({- 146 \pm 4{\rm kj/mol\,}RT} \right) $$\end{document}Allyl propargyl 2‐thiapropyl amine:\documentclass{article}\pagestyle{empty}\begin{document}$$ k\left({{\rm s}^{- 1}} \right) = 10^{12.55 \pm 0.38} \exp \left({- 166 \pm 5{\rm kj/mol\,}RT} \right) $$\end{document}Allyl methanesulfonyl propargyl amine:\documentclass{article}\pagestyle{empty}\begin{document}$$ k\left({{\rm s}^{- 1}} \right) = 10^{12.56 \pm 0.34} \exp \left({- 184 \pm 5{\rm kj/mol\,}RT} \right) $$\end{document}Nonconcerted mechanisms, involving polar six center cyclic transition states, are suggested for the elimination of allene and propene. © 1994 John Wiley & Sons, Inc.