Insights into the reaction mechanism of criegee intermediate with NO radical

The reaction mechanism of H2COO + NO, syn-CH3 CHOO + NO, and anti-CH3CHCOO + NO is studied using density functional theory (DFT) analysis. By analysis, four reaction pathways are obtained for each reaction. Among of them, the process of cyclization dissociation is the major pathway in all reaction systems, and the adsorbent process between criegee intermediate and NO is the rate-determining step in this pathway. The electron donating effect is dominant and plays a positive role in anti-CH3CHOO + NO reaction, while the steric hindrance effect is dominant and plays a negative role in syn-CH3CHOO + NO. Furthermore, the conformer-selective of electron donating effect from CH3 is stronger in anti-conformer than in syn-conformer. The present results enable a deep understanding of criegee intermediate chemistry.