Kaipara Revathy, Rajakumar B
Department of Chemistry , Indian Institute of Technology Madras , Chennai 600036 , India.
J Phys Chem A. 2018 Nov 1;122(43):8433-8445. doi: 10.1021/acs.jpca.8b06603. Epub 2018 Oct 18.
The temperature-dependent kinetics for the reaction of a Criegee intermediate (CHOO) with propionaldehyde (CHCHCHO) was investigated using canonical variational transition state theory (CVT) in conjunction with the small curvature tunneling (SCT) method and the interpolated single point energy (ISPE) method at the CCSD(T)/AUG-cc-pVTZ//B3LYP/6-311G(d,p) level of theory. A rich chemistry was depicted by the title reaction, though the contributions of all of the reaction pathways were limited to atmospheric pressure conditions. The reaction of CHOO with CHCHCHO was identified to proceed via the formation of secondary ozonide (SOZ), which then underwent a sequence of unimolecular isomerization and decomposition reactions to form a variety of products. The obtained rate coefficient for the formation of SOZ at 298 K was determined to be k = 2.44 × 10 cm molecule s. At low temperature, collisionally stabilized SOZ was found to be the more stable product. Contrarily, at high temperature, SOZ degraded to HCHO, and CHCHCOOH was found to be the major product. The complete degradation mechanism and thermochemistry for the reaction of CHOO with CHCHCHO along with their rate coefficients over the temperature range of 200-1000 K are reported.
在CCSD(T)/AUG-cc-pVTZ//B3LYP/6-311G(d,p)理论水平下，采用正则变分过渡态理论（CVT）结合小曲率隧道效应（SCT）方法和内插单点能量（ISPE）方法，研究了Criegee中间体（CHOO）与丙醛（CH₃CH₂CHO）反应的温度相关动力学。尽管所有反应途径的贡献都局限于大气压力条件下，但该反应呈现出丰富的化学反应。已确定CHOO与CH₃CH₂CHO的反应通过形成二级臭氧化物（SOZ）进行，然后SOZ经历一系列单分子异构化和分解反应以形成多种产物。在298 K时，得到的SOZ形成速率系数确定为k = 2.44×10⁻¹² cm³ molecule⁻¹ s⁻¹。在低温下，发现碰撞稳定的SOZ是更稳定的产物。相反，在高温下，SOZ降解为HCHO，并且发现CH₃CH₂COOH是主要产物。报道了CHOO与CH₃CH₂CHO反应的完整降解机理和热化学，以及它们在200 - 1000 K温度范围内的速率系数。
