三氟甲烷与乙烯基自由基气相反应的机理研究
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摘要
文章对CHF3与C2H3·反应的微观机理及反应路径特性进行了研究,并预测了不稳定物种CH2CHCF2·与CHF2CHFCH2·的生成焓(-222.2±6.7与-496.2±6.0kJ/mol)。计算显示,除氢抽提通道外,标题反应尚存在氟抽提(R1)、消氟化氢(R2)与自由基形成(R3)三类反应,其中,以氟抽提R1为基础的双步自由基形成通道R3′,是除氢抽提反应以外的热力学最佳路径。
Trifluoromethane is a strong greenhouse gas.The mechanism and the reaction path properties between CHF3 and C2H3 · were investigated,and the formation enthalpies of the unstable species CH2CHCF2·and CHF2CHFCH2· were predicted(-222.2±6.7and-496.2±6.0kJ/mol).The calculations indicate that the title reaction owns the fluorine abstraction(R1),the hydrogen fluoride elimination(R2)and the radical formation(R3)three reactions,besides the hydrogen abstraction reaction.Of which,the two-step radical formation channel R3′based on the fluorine abstraction R1 is the dominant reaction pathway thermodynamically,except for the hydrogen abstraction reaction.
Trifluoromethane is a strong greenhouse gas.The mechanism and the reaction path properties between CHF3 and C2H3 · were investigated,and the formation enthalpies of the unstable species CH2CHCF2·and CHF2CHFCH2· were predicted(-222.2±6.7and-496.2±6.0kJ/mol).The calculations indicate that the title reaction owns the fluorine abstraction(R1),the hydrogen fluoride elimination(R2)and the radical formation(R3)three reactions,besides the hydrogen abstraction reaction.Of which,the two-step radical formation channel R3′based on the fluorine abstraction R1 is the dominant reaction pathway thermodynamically,except for the hydrogen abstraction reaction.
引文
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[3]刘援,孙丹妮,张建君,等.中国履行《蒙特利尔议定书(基加利修正案)》减排三氟甲烷的对策分析[J].气候变化研究进展,2018,14(4):423-428.Liu Y,Sun D N,Zhang J J,et al.Measures Analysis for HFC-23Emission Mitigation in China Under the Kigali Amendment to the Montreal Protocol[J].Climate Change Research,2018,14(4):423-428.
[4] Han W,Kennedy E M,Kundu S K,et al.Experimental and Chemical Kinetic Study of the Pyrolysis of Trifluoroethane and the Reaction of Trifluoromethane with Methane[J].Journal of Fluorine Chemistry,2010,131:751-760.DOI:10.1016/j.jfluchem.2010.03.012.
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[7]冯丽霞,郑慧敏,田宏伟.CHF3与O(3P)反应机理的理论研究[J].分子科学学报,2014,30(1):12-17.Feng L X,Zheng H M,Tian H W.Theoretical Study on the Reaction Mechanism of CHF3 with O(3P)[J].Journal of Molecular Science,2014,30(1):12-17.
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[10]冯丽霞,郑慧敏,左玉.CH3F与O(3P)反应机理的量子化学研究[J].太原师范学院学报(自然科学版),2010,9(2):31-35.Feng L X,Zheng H M,Zuo Y.Quantum Chemistry Study on the Reaction Mechanism of CH3F with O(3P)[J].Journal of Taiyuan Normal University,2010,9(2):31-35.
[11]冯丽霞,贾杰,杨玉伟.二氟甲烷与氧原子大气反应机理的计算研究[J].陕西师范大学学报(自然科学版),2017,45(3):49-55.Feng L X,Jia J,Yang Y W.Computational Study on the Mechanism of Atmospheric Reaction Between Difluoromethane and Atomic Oxygen[J].Journal of Shaanxi Normal University,2017,45(3):49-55.
[12] Frisch M J,Trucks G W,Schlegel H B,et al.Gaussian 09[CP].Revision B.01,Gaussian Inc.:Wallingford CT,2010.
[13] Feng L,Jia J,Wang A,et al.Direct Dynamics Study on the Hydrogen Abstraction Reaction of Fluoromethanes with Vinyl Radical[J].Computational and Theoretical Chemistry,2013,1020:143-150.DOI:org/10.1016/j.comptc.2013.07.025.
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[15] Berkowitz J,Ellison G B,Gutman D.Three Methods to Measure RH Bond Energies[J].J Phys Chem,1994,98(11):2744-2765.DOI:0022-3654/94/2098-2144$04.50/0.
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