高等学校化学学报 ›› 2016, Vol. 37 ›› Issue (3): 513.doi: 10.7503/cjcu20150742

• 物理化学 • 上一篇    下一篇

Criegee中间体CH3CHOO与OH自由基反应机理的理论研究

高志芳, 王渭娜, 马倩, 刘峰毅, wlwang@snnu.edu.cn   

  1. 陕西省大分子科学重点实验室, 陕西师范大学化学化工学院, 西安 710119
  • 收稿日期:2015-09-22 出版日期:2016-03-10 发布日期:2016-01-24
  • 基金资助:
    国家自然科学基金(批准号: 21473108, 21473107)和陕西省重点科技创新团队基金(批准号: 2013KCT-17)资助

Theoretical Studies on the Reaction Mechanism of Criegee Intermediates CH3CHOO with OH Radicals

GAO Zhifang, WANG Weina, MA Qian, LIU Fengyi, WANG Wenliang*   

  1. School of Chemistry and Chemical Engineering, Shaanxi Normal University, Key Laboratory for Macromolecular Science of Shaanxi Province, Xi’an 710119, China
  • Received:2015-09-22 Online:2016-03-10 Published:2016-01-24
  • Contact: WANG Wenliang
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos.21473108, 21473107) and the Innovative Team of Key Science and Technology of Shaanxi Province, China(No.2013KCT-17)

摘要:

采用CCSD(T)//B3LYP/6-311+G(d,p)方法研究了Criegee中间体CH3CHOO与OH自由基反应的微观机理. 结果表明, 上述反应存在抽氢、 加成-分解和氧化3类反应通道, 其中, syn-CH3CHOO+OH以抽β-H为优势通道, 表观活化能为-4.88 kJ/mol; anti-CH3CHOO+OH则以加成-分解反应为优势通道, 表观活化能为-13.25 kJ/mol. 在加成-分解和氧化反应通道中, anti-构象的能垒均低于syn-构象, 而抽氢反应则是syn-(β-H)的能垒低于anti-构象. 速率常数计算表明, anti-构象的加成-分解反应通道具有显著的负温度效应; syn-和anti-构象的氧化通道具有显著的正温度效应. 3类反应具有显著不同的温度效应, 说明通过改变温度可显著调节3类反应的相对速率.

关键词: Criegee中间体, CH3CHOO自由基, OH自由基, 反应机理, 速率常数

Abstract:

The reaction mechanism of CH3CHOO with OH was studied at the CCSD(T)//B3LYP/6-311+G(d,p) level. The results show that the detailed mechanism mainly includes hydrogen abstraction, addition-decomposition and oxidation reactions. The calculations show that β-H abstraction reaction is favoured in the syn-CH3CHOO reaction with OH with a apparent activation energy(Eapp) of -4.88 kJ/mol, whereas the addition-decomposition channel is advantaged in the reaction of anti-CH3CHOO with OH in combination with a Eapp of -13.25 kJ/mol. The barriers of anti-CH3CHOO are lower than that of the syn-CH3CHOO in addition-decomposition and oxidation reactions, while the syn-CH3CHOO is lower than anti-CH3CHOO in the β-H abstraction pathway. The rate constant of addition-decomposition in the reaction of anti-CH3CHOO satisfies a strong negative temperature dependent, while oxidation channels of syn-/anti-CH3CHOO obey a positive temperature effect. The temperature dependent of three kind of reactions are different, which makes their relative rate can be controlled by adjusting the temperature.

Key words: Criegee intermediate, CH3CHOO radical, OH radical, Reaction mechanism, Rate constant

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