Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (12): 2898-2904.doi: 10.3866/PKU.WHXB201609142

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Reaction Mechanism of Criegee Intermediate CH3CHOO with H2O and the Acid Catalytic Effect

Zhi-Fang GAO,Li-Ting ZHOU,Wei-Na WANG,Feng-Yi LIU,Wen-Liang WANG*()   

  • Received:2016-07-18 Published:2016-11-30
  • Contact: Wen-Liang WANG
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21473108,21473107);Fundamental Research Funds for ShaanxiInnovative Team of Key Science and Technology, China(2013KCT-17);and Fundamental Research Funds for the Central Universities, China(JK201601005)


The catalytic effect of H2O and six kinds of organic acids (e.g., formic acid) on the reaction of CH3CHOO with H2O is studied at the CCSD(T)//B3LYP/6-311+G(d,p) level. The results reveal that two possible channels exist as the double proton transfer and addition, of which the latter dominates for the non-catalytic reactions. For the additions, the OH of water is added to the α-C of CH3CHOO, and the H atoms migrate to the end oxygen atoms. Catalysts such as H2O and organic acid can form a hydrogen-bonded complex with CH3CHOO, which promotes the H transfer and thus significantly reduces the elementary reaction energy barrier and apparent activation energy when compared with that of the non-catalytic reaction. The catalytic effect is proportional to the strength of the organic acids. For example, for the formation of syn-HAHP catalyzed by H2O (pKa=15.7), formic acid (pKa=3.75) and oxalic acid (pKa=1.23), the energy barrier is reduced from 69.12 to 40.78, 18.88 and 10.61 kJ·mol-1, respectively. In addition, the non-catalytic reaction has a positive activation energy, whereas the catalytic reactions have an negative apparent activation energy.

Key words: Criegee intermediate, CH3CHOO, Acid catalysis, Addition reaction