Ai Li-ling, Liu Jing-yao
Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun, 130023, People's Republic of China.
J Mol Model. 2014 Apr;20(4):2179. doi: 10.1007/s00894-014-2179-7. Epub 2014 Mar 19.
A detailed theoretical investigation was performed on the mechanisms for the reactions of E/Z-CF₃CF= CFCF₃ with OH radicals by means of density functional theory (DFT). The geometries and frequencies of all the stationary points and the minimum energy path (MEP) are calculated at the M06-2X/aug-cc-pVDZ level. To obtain more reliable energy information, the high-level single-point energies are further refined at the MCG3/3 level. Possible reaction pathways including the addition-elimination and the OH-initiated oxidation pathways are considered. A complete description of the possible degradation mechanisms of E/Z-CF₃CF = CFCF₃ in the absence and presence of O₂/NO has been presented. The calculated results demonstrate that the most accessible products are CF₃, CF(OH)= CFCF₃, CF(O)CHFCF₃, CF₃C(O)F, and CHFCF₃ via the dissociation reactions starting from the addition intermediates IM1E/IM1Z in the absence of O₂/NO. While in the atmosphere, IM1E/IM1Z can further react with O₂/NO to form the likely products CF₃C(O)F and HO₂. The calculated results are consistent with the experimental results.
借助密度泛函理论（DFT），对E/Z-CF₃CF= CFCF₃与OH自由基反应的机理进行了详细的理论研究。在M06-2X/aug-cc-pVDZ水平上计算了所有驻点的几何结构和频率以及最小能量路径（MEP）。为了获得更可靠的能量信息，在MCG3/3水平上进一步优化了高水平单点能量。考虑了包括加成-消除和OH引发的氧化途径在内的可能反应途径。给出了在不存在和存在O₂/NO的情况下E/Z-CF₃CF = CFCF₃可能的降解机理的完整描述。计算结果表明，在不存在O₂/NO的情况下，通过从加成中间体IM1E/IM1Z开始的解离反应，最容易得到的产物是CF₃、CF(OH)= CFCF₃、CF(O)CHFCF₃、CF₃C(O)F和CHFCF₃。而在大气中，IM1E/IM1Z可进一步与O₂/NO反应形成可能的产物CF₃C(O)F和HO₂。计算结果与实验结果一致。
