论文部分内容阅读
F~-和氟乙烷的气相反应(E_2和S_N 2反应)是用从头计算法来进行研究的。研究发现,E2反应由四个基本历程构成。这四步历程分别是:1.第一中间体的形成,2.净E2反应产生第二中间体 3.第二中间体的解离,4.产物的形成。在净E2反应中,C—H键和C—F键的断裂是同步的。 S_N 2反应有三个基本历程:1.第一中间体的形成,2.净 S_N 2反应产生第二中间体,3.第二中间体的解离。S_N 2反应的第一中间体不同于E2反应的第一中间体。通过对E2和S_N 2反应比较发现,在气相中更有利E2反应的进行。本文在计算结果的基础上讨论了E2和S_N 2在溶液中的反应历程。本文还将计算结果与文献报道的实验数据进行了比较分析,并就E1_C B历程的可能性进行了讨论。
The gas-phase reaction of F ~ - with fluoroethane (E_2 and S_N 2 reactions) was studied by ab initio method. The study found that E2 reaction consists of four basic processes. This four-step process is respectively: 1. The formation of the first intermediate, 2. The net E2 reaction produces the second intermediate 3. The dissociation of the second intermediate, 4. The formation of the product. In the net E2 reaction, the cleavage of the C-H and C-F bonds is synchronous. S_N 2 reaction has three basic processes: 1. The formation of the first intermediate, 2. The net S_N 2 reaction produces the second intermediate, 3. The dissociation of the second intermediate. The first intermediate of the S_N2 reaction is different from the first intermediate of the E2 reaction. By comparing the reaction of E2 and S_N 2, it was found that the reaction of E2 was more favorable in the gas phase. In this paper, we discuss the reaction of E2 and S_N 2 in solution based on the calculated results. This paper also compares the results with the experimental data reported in the literature and discusses the possibility of the E1_C B process.