Effect of multifunctional compound monoethanolamine on Criegee intermediates reactions and its atmospheric implications.

Abstract

The reactions of Criegee intermediates with trace gases (such as alcohols, amines, and acids) are primarily dependent on the trace gases' functional group activity. In this study, we used density functional theory calculations and ab initio dynamics simulation methods to explore the synergistic effect of NH2 and OH groups, in the multifunctional compound monoethanolamine (MEA), on the Criegee reaction. The results showed that among the four evaluated MEA configurations, two functional groups in the g'Gg' and tGg' configurations, -NH2 and -OH, have the synergistic effect on the C2 stabilized Criegee intermediates (sCIs). At the gas-liquid interface, sCIs react with NH2 groups of MEA molecules directly or are mediated by water molecules, resulting in additional product formation. The rate calculation indicated that the reaction of sCIs with NH2 groups of MEA molecules is prior to that with OH groups. In addition, OH groups promote the reactions between sCIs and NH2 groups of MEA, while the presence of NH2 groups weakens the reactions of sCIs and OH groups of MEA to some extent. At 298K, the total rate constant of anti-CH3CHOO with NH2 group of MEA is 4.26×10-11cm3molecule-1s-1, which is four orders of magnitude higher than that of anti-CH3CHOO hydration. Under low humidity conditions, the reactions between sCIs and MEA could contribute to the removal of sCIs.