【作者】 于艳波；

【导师】 潘秀梅；

【作者基本信息】 东北师范大学 ， 物理化学， 2011， 硕士

【摘要】 氢氟醚（HF_Es）因为它的零平流层臭氧耗竭和相对较低的GWP,因此被选作氯氟碳CF_Cs的第三代替代物。HF_Es已经被广泛应用于各种工业领域。从环境,生态,健康的观点看,了解商业应用和工业生产中使用的各种HF_Es对环境的危害是很重要的。因此,为了更好的评价氢氟醚对大气环境的影响以及确定它们在同温层中的大气寿命,很多理论工作深入研究了HF_Es与自由基的反应机理和动力学行为。这些研究对控制和解决它们对环境的环境污染有重要的意义。本论文利用现代量子化学理论详细阐述了CF₃OCHF₂ + O（1D）反应的反应机理。利用从头算和密度泛函直接动力学方法研究了CHF₂OCHF₂ + Cl反应的微观机理和速率常数。从而为进一步研究和利用这些反应提供了理论依据。本论文的主要工作概括如下:一、CF₃OCHF₂ + O（1D）反应机理的理论研究。运用密度泛函DF_T （B3LYP）和MC-QCISD方法在6-311 G（d,p）基组水平上对CF₃OCHF₂ + O（1D）的反应机理进行了全面细致的研究。获得了该反应中势能面上各稳定点的几何构型、振动频率和单点能等信息。利用同构反应（Ra-Rc）,在理论上估算了反应物CF₃OCHF₂的标准生成焓数据。另外,计算了主要反应通道的反应焓。计算结果表明,CF₃OCHF₂ + O（1D）反应可能有三种起始络合方式,分别是O（1D）插入到C-H键;O（1D）插入到C-O键;O（1D）进攻F_原子。共形成七个前期络合物。通过分析比较,有五条反应路径是可以实现的。在这些反应中我们认为P2,P3和P4是主要产物,而P1和P5是次要产物。二、CHF₂OCHF₂ + Cl的微观反应机理的理论研究。应用G₃MP₂//UMP₂/6-311 G（d,p）方法研究了CHF₂OCHF₂ + Cl的H-提取反应机理。计算结果表明,在UMP₂/6-311G（d,p）理论水平下计算得到的反应物、产物的几何构型和频率值分别与可获得的实验值吻合得比较好。我们在G₃M₂//UMP₂/6-311G（d,p）水平上应用同构反应估算了CHF₂OCHF₂的标准生成焓。我们希望我们的计算对于深入研究该反应的机制可能有帮助作用,并且对于将来的实验研究也能够提供参考和帮助。更多还原

【Abstract】 Hydrofluoroethers （HFEs） are being used as third generation replacements to chlorofluorocarbons （CFCs） because of their nearly zero stratospheric ozone depletion and relatively low global warming potential. HFEs have been used in various industrial applications. From the environmental, ecological, and health points of view, it is important to understand their environmental risks for these HFEs from a diversity of commercial applications and industrial processes. Therefore, in order to better assess the atmospheric and environmental impact of HFEs, the mechanisms and kinetics of the HFEs with radicals have been studied deeply by many theoretical investigations. They are very important to control atmospheric pollutions.The quantum chemistry methods were used to investigate the reaction mechanisms of CF3OCHF2 + O（1D） reaction. Using ab initio and density function theory （DFT） chemistry methods, we studied the the detailed mechanisms and rate constant of CHF₂OCHF₂ + Cl. Thus, useful information and elementary theoretical evidence are provided for further studying these reactions experimentally.The results of this work are summarized as follows:1. The theoretical study on the of CF₃OCHF₂ + O（1D） reaction are investigated deeply using DFT （B3LYP） and MC-QCISD methods with 6-311G（d,p） basis set. The geometries, vibrational frequencies and the singlet point energy of all stationary points on potential energy surfaces （PESs） are obtained. Standard enthalpies of formation of CF₃OCHF₂ are estimated theoretically using group-balanced isodesmic reactions （Ra-Rc）. Moreover, The reaction enthalpies of the major reaction channels are calculated. The results show that seven different intermediates are located at the reactant side by three initial association ways: i.e. insertion into C-H bond, insertion into C-O bond, or addition to the F atom of CF3OCHF2, respectively. There are five reaction pathways are feasible and five products may be obtained. Among them, P₂, P_, and P₄ are primary products, while P1 and P5 are minor products.2. The theoretical investigation on the H-abstraction reaction mechanism of the reaction CHF₂OCHF₂ + Cl. The optimized geometries and harmonic frequencies of the reactants, products, hydrogen-bonded complex and transition states are obtained at the G3MP₂//UMP2/6-311G（d,p） level for the H-abstraction reaction mechanism of CHF2OCHF2 + Cl. The results are consistant with the available experimental data. Standard enthalpies of formation of CHF2OCHF2 radical are estimated theoretically using group-balanced isodesmic reactions. We hope our calculation may be useful for gaining insight into the mechanism and may provide useful information for future experimental studies of the title reaction.更多还原