Formation of methyl ketenimine (CH 3 CH=C=NH) and ethylcyanide (CH 3 CH 2 C≡N) isomers through successive hydrogenations of acrylonitrile (CH 2 =CH−C≡N) under interstellar conditions: The role of CH 3 C°H−C≡N radical in the activation of the cyano group chemistry
Abstract
Possible formation routes of interstellar amino acids have been proposed where the first step consists in the transformation of organic nitriles (RCH2 − C≡N) into ketenimines (RCH = C = NH). Such a transformation shows high-energy barriers and needs energetic processing to occur. We show in this study that the CN bond could be activated through H-addition reactions to form ketenimines when starting from organic α, β-unsaturated nitriles (C≡N). Consequently, both methyl ketenimine CH3CH = C = NH and ethylcyanide CH3CH2C≡N might have their origin from H2C = CH − C≡N + 2H reaction occurring on the interstellar icy grains. During the hydrogenation of H2C = CH − C≡N ice under interstellar conditions, CH3CH2C≡N has been formed with an abundance 10 times higher than that of CH3CH = C = NH. Our measurements lead us to conclude that such a distribution would be directly linked to the π-electrons delocalization H3C − C°H − C≡N ↔ H3C − CH = C = N° occurring during the reduction of the CC double bond of acrylonitrile.
Origin : Files produced by the author(s)
Loading...