高等学校化学学报 ›› 2017, Vol. 38 ›› Issue (4): 613.doi: 10.7503/cjcu20160803

• 物理化学 • 上一篇    下一篇

Criegee中间体RCHOO(R=H,CH3)与NCO的反应机理

马倩, 王渭娜, 赵强莉, 刘峰毅, 王文亮()   

  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:2016-11-18 出版日期:2017-04-10 发布日期:2017-03-22
  • 作者简介:联系人简介: 王文亮, 男, 教授, 博士生导师, 主要从事理论与计算化学研究. E-mail: wlwang@snnu.edu.cn
  • 基金资助:
    国家自然科学基金(批准号: 21473108, 21473107)、 陕西省重点科技创新团队基金(批准号: 2013KCT-17)和中国博士后科学基金(批准号: 2016M592740)资助

Theoretical Studies on the Reaction Mechanism of Criegee Intermediates RCHOO(R=H, CH3) with NCO Radical

MA Qian, WANG Weina, ZHAO Qiangli, LIU Fengyi, WANG Wenliang*()   

  1. Key Laboratory for Macromolecular Science of Shaanxi Province,School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China
  • Received:2016-11-18 Online:2017-04-10 Published:2017-03-22
  • Contact: WANG Wenliang E-mail:wlwang@snnu.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos.21473108, 21473107), the Innovative Team of Key Science and Technology of Shaanxi Province, China(No.2013KCT-17) and the China Postdoctoral Science Foundation Funded Project(No.2016M592740)

摘要:

采用CCSD(T)/aug-cc-pVTZ//B3LYP/6-311+G(2df,2p)方法对Criegee中间体RCHOO(R=H,CH3)与NCO反应的机理进行了研究, 利用经典过渡态理论(TST)并结合Eckart校正模型计算了标题反应在298~500 K范围内优势通道的速率常数. 结果表明, 上述反应包含亲核加成、 氧化和抽氢3类机理, 其中每类又包括NCO中N和O分别进攻的两种形式. 亲核加成反应中O端进攻为优势通道, 氧化和抽氢反应则是N端进攻为优势通道; 甲基取代使CH3CHOO反应活性高于CH2OO; anti-CH3CHOO的加成及氧化反应活性高于syn-CH3CHOO, 而抽氢反应则是syn-CH3CHOO的活性高于anti-CH3CHOO. anti-构象对总速率常数的贡献大于syn-构象, 且总速率常数具有显著的负温度效应.

关键词: Criegee 中间体, NCO, 反应机理, 速率常数

Abstract:

A comprehensive theoretical study about the reaction of RCHOO(R=H, CH3) with NCO was performed at the CCSD(T)/aug-cc-pVTZ//B3LYP/6-311+G(2df,2p) level. The rate coefficients for the dominant reaction channels were determined at 298—500 K via conventional transition state theory(TST) with a Eckart tunneling. The results show that the detailed mechanism mainly includes addition, oxidation and hydrogen abstraction reactions. N and O atoms of the NCO radical can react to RCHOO(R=H and CH3) in each reaction mode. Moreover, the end O atom of NCO addition to RCHOO(R=H and CH3) α-C is favored for the addition reaction, while the reactions involving the end N atom of NCO is advantaged in both oxidation and hydrogen abstraction. The methyl substituents in the CH2OO produce an increase of the reactivity. Anti-CH3CHOO shows a higher reactivity than syn-CH3CHOO towards addition and oxidation reaction, but for the hydrogen abstraction, syn-CH3CHOO is significantly more reactive than anti-CH3CHOO. The contribution of anti-CH3CHOO to the overall rate constant is greater than that of syn-CH3CHOO, and the total rate constant satisfies a strong negative temperature effect.

Key words: Criegee intermediate, NCO, Reaction mechanism, Rate constant

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