Sun Cuihong, Xu Baoen, Lv Liqiang, Zhang Shaowen
College of Chemical Engineering, Shijiazhuang University, Shijiazhuang, 050035, P. R. China.
School of Chemistry and Chemical Engineering, Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, South Zhongguancun Street #5, Haidian District, Beijing, 100081, P. R. China.
Phys Chem Chem Phys. 2019 Aug 14;21(30):16583-16590. doi: 10.1039/c9cp02644d. Epub 2019 Jul 17.
The detailed reaction mechanism of the Criegee intermediate CHOO with ethylene and acetylene has been investigated by using the HL//M06-2X/AUG-cc-pVTZ method. The 1,3-cycloaddition of CHOO to the unsaturated bond of ethylene or acetylene forms a five-membered ring adduct. For the reaction of CHOO with ethylene, the subsequent ring-opening, H-shift isomerization and decomposition result in the formation of ethenol + HCHO and acetaldehyde + HCHO, and for the reaction of CHOO with acetylene, the adduct proceeds via ring-opening and H-shift isomerization forming malonaldehyde. The calculated overall rate constant increases in the temperature range of 200-500 K, and at 298 K, it is 3.91 × 10 cm molecule s for the CHOO + CH reaction and 1.27 × 10 cm molecule s for the CHOO + CH reaction. The product branching ratio of the CHOO + CH reaction is pressure dependent, and the adduct tends to decompose to ethenol + HCHO and acetaldehyde + HCHO at lower pressures and higher temperatures. For the CHOO + CH reaction, the adduct isomerizes completely to malonaldehyde in the temperature range of 200-500 K and the pressure range of 100-1000 Torr.
采用HL//M06 - 2X/AUG - cc - pVTZ方法研究了Criegee中间体CHOO与乙烯和乙炔的详细反应机理。CHOO与乙烯或乙炔不饱和键的1,3 - 环加成形成五元环加合物。对于CHOO与乙烯的反应，随后的开环、H迁移异构化和分解导致生成乙烯醇 + 甲醛和乙醛 + 甲醛；对于CHOO与乙炔的反应，加合物通过开环和H迁移异构化生成丙二醛。计算得到的总速率常数在200 - 500 K温度范围内增大，在298 K时，CHOO + CH₂反应的总速率常数为3.91×10⁻¹⁰ cm³ molecule⁻¹ s⁻¹，CHOO + C₂H₂反应的总速率常数为1.27×10⁻¹⁰ cm³ molecule⁻¹ s⁻¹。CHOO + CH₂反应的产物分支比与压力有关，在较低压力和较高温度下，加合物倾向于分解为乙烯醇 + 甲醛和乙醛 + 甲醛。对于CHOO + C₂H₂反应，在200 - 500 K温度范围和100 - 1000 Torr压力范围内，加合物完全异构化为丙二醛。
