在 HX (X = Br,I) + C2H5反应中,H抽象和X抽象路径之间的竞争
1MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary. cangtaoyin@foxmail.com.
在HX (X=Br,I) 和C2H5之间的高能反应表现出复杂的动态. 碰撞能量的增加有利于X-抽象而不是H-抽象,振动刺激会以不同的方式影响这两种途径.
科学领域:
- 化学动力学和反应机制
- 计算化学和理论建模理论建模
背景情况:
- 准确的潜在能量表面 (PES) 对于理解化学反应至关重要.
- 之前对HX + C2H5反应的研究受限于可用的PES的能量范围.
研究的目的:
- 改进和扩展HX + C2H5反应的高水平初始潜在能量表面.
- 为了研究这些反应在较高的碰撞能量 (30-80 kcal mol-1) 的动态.
- 阐明振动激发和碰撞能量对反应路径的影响.
主要方法:
- 使用先进的初始方法 (ManyHF-UCCSD(T) -F12a + SOcorr ((MRCI-F12+Q)) 在旋转轨道校正的潜在能量表面上开发新的高能点.
- 在改进的PES上进行了准经典的轨迹模拟.
- 分析反应概率,振动效应,效应和散射分布.
主要成果:
- 碰撞能量的增加导致H抽象概率降低,X抽象反应活性显著增加.
- 在高碰撞能量时,H和X抽象路径都成为共同的主导.
- 在 HX 中的振动激发增强了这两种途径,特别是 X 抽象; C2H5 振动模式显示了模式特定的效果,抑制了 H 抽象.
- 分散分析表明,H和X抽象的直接剥离/反弹机制分别为H和X抽象.
结论:
- 这项研究提供了对HX + C2H5反应动态在扩大能量范围的更全面的了解.
- 碰撞能量和振动模式在确定H和X抽象路径之间的竞争中发挥着关键作用.
- 这些发现强调了准确的PES和轨迹模拟对于预测反应结果的重要性.
更多相关视频
06:34Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS
Published on: June 20, 2014
08:25Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
相关概念视频
Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene
Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control
Radical Formation: Abstraction
Even though homolysis produces radicals, it is different from radical...
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
