Theoretical study on the mechanism of CH 3 NH 2 and O 3 atmospheric reaction

Abstract

Reaction pathways of methylamine with ozone on the singlet potential energy profile have been investigated at the RB3LYP/6-311 ++G (3df–3pd) computational level. Calculated results reveal that six kinds of products P1 (CH3NO + H2O2), P2 (CH3NH + OH + O2), P3 (NH2CH + HO2+ OH), P4 (CH2NH + H2O +O2), P5 (NH2CH2OH + O2), P6 (NH3+ CH2O +O2) are obtained through variety of transformation of one reactant complex C1. Cleavage and formation of the chemical bonds in the reaction pathways have been discussed using the structural parameters. Based on the calculations, the title reaction leads to NH3+ CH2O + O2 as thermodynamic adducts in an exothermic process by −76.28 kcal/mol in heat realizing and spontaneous reaction by −86.71 kcal/mol in standard Gibbs free energy. From a kinetic viewpoint, the production of CH3NH + OH + O2 adducts with one transition state is the most favoured path. A possible mechanism for the CH3NH2+O3 reaction on the singlet state are suggested. Six kinds of products from one reactant complex C1 are obtained. Cleavage and formation of chemical bonds in the reaction pathways are discussed using structural parameters.