揭示甲非氧化合对铁含有热石的活性位点和反应途径
Hao Zhang1, Aleksei Bolshakov1, Raghavendra Meena2,3
1Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands.
Angewandte Chemie (International ed. in English)
|July 3, 2023
概括
甲的非氧化合将天然气转化为乙烯使用[Fe]二氧化. 在MFI和CHA的热带石结构中,对乙烯和乙具有很高的选择性,活性铁位点能够有效地再生.
科学领域:
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 非氧化甲合提供了直接通往有价值的烯的途径,如天然气中的乙烯.
- 含有铁 ([Fe]zeolites) 的化被探索为这种转变的催化剂.
- 了解活性位点和反应机制对于催化剂优化至关重要.
研究的目的:
- 为了合成和表征有性[Fe]二氧化物与MFI和CHA拓的非氧化甲合.
- 调查催化性能,特别是对乙烯和乙的选择性.
- 阐明在甲转化过程中涉及的活性位点和反应中间体的性质.
主要方法:
- 合成具有MFI和CHA结构的性[Fe]化物.
- 甲合的气相催化反应.
- 在现场X射线吸收光谱 (XAS) 用于活性部位的特征.
- 光电子光离子巧合光谱 (PEPICO) 用于中间识别.
主要成果:
- 实现了对乙烯 (>90%对于MFI,>99%对于CHA) 和乙的高选择性.
- 通过焦炭燃烧证明了非活化催化剂的再生.
- XAS显示了Fe3+的减少到活性Fe2+和Fe (氧) 碳化物物种.
- 佩皮科确定了甲基激素作为关键中间体,以太因激素合和脱而形成.
结论:
- 具有MFI和CHA拓的[Fe]zeolites是非氧化甲与乙烯和乙烯合的有效催化剂.
- 反应通过甲基中间体进行,对于MFI和CHA拓观察到不同的途径.
- 对于[Fe]MFI的拟议反应网络,可以考虑多芳香物种的形成,这种物种在[Fe]CHA.中不存在.
相关概念视频
02:50Catalysis
27.1K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
27.1K
01:46Oxidative Cleavage of Alkenes: Ozonolysis
10.6K
In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
10.6K
01:22Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
1.9K
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction.
1.9K
02:13Reduction of Alkenes: Catalytic Hydrogenation
12.2K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
12.2K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.8K
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
7.8K
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
10.4K
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
10.4K