Methanimine As A key Precursor Of Aimines In The Interstellar Medium: The Case Of Propargylimine



A gas-phase formation route is proposed for the recently detected propargylimine molecule. In analogy to other imines, such as cyanomethanimine, the addition of a reactive radical (C2H in the present case) to methanimine (CH2NH}) leads to reaction channels open also in the harsh conditions of the interstellar medium.

Three possible isomers can be formed in the CH2NH + C2H reaction: Z- and E-propargylimine (Z-,E-PGIM) as well as N-ethynyl-methanimine (N-EMIM). For both PGIM species, the computed global rate coefficient is nearly constant in the 20-300 K temperature range, and of the order of 2-3 × 10−10 cm3 molecule−1 s−1, while that for N-EMIM is about two orders of magnitude smaller. Assuming equal destruction rates for the two isomers, these results imply an abundance ratio for PGIM of [Z]/[E] ∼ 1.5, which is only slightly underestimated with respect to the observational datum.

Jacopo Lupi, Cristina Puzzarini, Vincenzo Barone

Comments: 10 pages, 4 figures, 2 tables. Accepted in ApJL
Subjects: Astrophysics of Galaxies (astro-ph.GA); Chemical Physics (physics.chem-ph); Computational Physics (physics.comp-ph)
Cite as: arXiv:2010.11651 [astro-ph.GA] (or arXiv:2010.11651v1 [astro-ph.GA] for this version)
Submission history
From: Jacopo Lupi
[v1] Thu, 22 Oct 2020 12:38:33 UTC (2,952 KB)
Astrobiology, Asrochemistry

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