The aliphatic amines, especially methylamine [CH3NH2], dimethylamine [(CH3)2NH] and trimethylamine [(CH3)3N], are emitted to the atmosphere from animal husbandry and by industry. These amines have received some attention in the context of their potential role as precursors of HCN and N2O, which is a greenhouse gas and the main source of stratospheric NOx. The photo-oxidation products of methylamine are nitrosamine, a carcinogen, and methanimine (CH2=NH); other imines originate from photo-oxidation of other alkyl amines. The atmospheric fate of CH2=NH is not known. Because the compound is highly reactive, soluble in water, and sticky, experiments will be difficult. Methaneimine is isoelectronic with C2H4 and H2CO, which might be good analogues for its atmospheric reactions, except that they react so differently from each other. Thus theoretical methods may be useful. CCSD(T) and BHandHLYP with the aug-cc-pVTZ basis set are used to compute geometries and frequencies of all species and minimum energy paths involved in the OH + CH2=NH reaction system. Canonical VTST, SCTST, and RRKM/ME calculations provided temperature- and pressure-dependent rate constants. The results show that OH radicals can both add to the double bond in CH2=NH and abstract hydrogen atoms; it thus has similarities to both OH + H2C=O and OH + H2C=CH2.

Reaction of OH + CH<sub>2</sub>=NH (methanimine): A theoretical study

248th National Meeting (2014)

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Reaction of OH + CH2=NH (methanimine): A theoretical study

Reaction of OH + CH₂=NH (methanimine): A theoretical study