理论研究烯替代剂对氧化和硫化的抽象反应的影响
1School of Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, R.O.C. midesu@cc.kmu.edu.tw
Journal of the American Chemical Society
|October 10, 2002
概括
与氧化和硫化的烯反应是有利的,特别是与基替代剂. 脱氧化更具有外热性和动力学优势,而不是对烯的脱硫化.
科学领域:
- 计算化学计算化学
- 反应机制 反应机制
- 有机化学 有机化学
背景情况:
- 烯是具有多种应用的反应性中间体.
- 了解它们的反应途径对于合成化学至关重要.
- 氧化和硫化是常见的循环乙烯和硫乙烯.
研究的目的:
- 为了研究与氧化和硫化的烯提取反应的潜在能量表面.
- 为了确定不同烯物种的相对反应性.
- 分析替代剂对反应能量和机制的影响.
主要方法:
- 密度函数理论 (B3LYP) 的计算.
- 从一开始 (QCISD) 的计算.
- 包含零点校正以准确确定能量.
主要成果:
- 反应通过类复合体和双中心过渡状态进行.
- 基替代烯提取比pi捐赠体替代的更有利.
- 脱氧比脱硫更具有外热性和动力学上的优势.
结论:
- 烯的反应性受到替代剂类型的显著影响.
- 基替代剂增强了抽象反应的有利性.
- 脱氧反应通常比脱硫更好.
更多相关视频
相关概念视频
Redox Reactions
Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...
Oxidation-Reduction Reactions
Oxidation–Reduction Reactions
Oxidation Numbers
In redox reactions, the transfer of electrons occurs between reacting species. Electron transfer is described by a hypothetical number called the oxidation number (or oxidation state). It represents the effective charge of an atom or element, which is assigned using a set of rules.
SN2 Reaction: Kinetics
Kinetic Studies and Significance
In a chemical reaction, a relationship exists between the concentration of reactants and the rate at which the reaction proceeds. The study to measure this relationship is known as the kinetics of a chemical reaction. Kinetic studies are used to deduce the rate law of a chemical reaction, which provides information about the species involved during the transition state of the rate-determining step. Thus, kinetic studies help to derive the mechanism of a reaction.
In a chemical reaction, a relationship exists between the concentration of reactants and the rate at which the reaction proceeds. The study to measure this relationship is known as the kinetics of a chemical reaction. Kinetic studies are used to deduce the rate law of a chemical reaction, which provides information about the species involved during the transition state of the rate-determining step. Thus, kinetic studies help to derive the mechanism of a reaction.
Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...


