在微孔结构中限制对乙烯寡合化金属催化剂的活性和选择性的影响的计算研究
Hervé Toulhoat1, Mireille Lontsi Fomena, Theodorus de Bruin
1Direction Scientifique, IFP Energies nouvelles, Rueil-Malmaison, France. herve.toulhoat@ifpenergiesnouvelles.fr
Journal of the American Chemical Society
|February 10, 2011
概括
封闭在石中改变了乙烯寡合化金属催化剂的性能. 模拟显示毛孔大小影响活动和选择性,使得优化特定产品的产量,如α-octene.
科学领域:
- 不同质的催化剂.
- 材料科学 材料科学 材料科学
- 计算化学计算化学
背景情况:
- 金属催化剂对于乙烯的寡合化至关重要.
- 石结构为催化反应提供可调节的环境.
- 了解封闭效应是催化剂设计的关键.
研究的目的:
- 调查热带石封闭对金属催化剂活性和选择性的影响.
- 在乙烯寡合化中探索结构性能关系.
- 确定针对性产品形成的最佳热石孔径.
主要方法:
- 大法典蒙特卡罗 (GCMC) 模拟来模拟客户互动.
- 对各种热带石框架 (MAZ,AET,DON,FAU,VFI) 的研究.
- 微动力学建模用于预测催化活性和选择性.
主要成果:
- 建立了吸附度和分子体积之间的线性相关性,取决于焦化石孔径大小.
- 证明了固体排斥效应,限制了在较小孔隙中的吸附.
- 预测由于限制导致催化剂活性和选择性的显著变化,包括增强的α-octene的生产.
结论:
- 泽奥利特孔径大小对乙烯寡合化中的金属催化剂行为产生了关键影响.
- 限制效应可以用来控制产品的选择性.
- 模拟提供了一个设计优化的封闭催化系统的途径.
相关概念视频
Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Heterogeneous Catalysis
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The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...


