Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

Reduction of Alkynes to trans-Alkenes: Sodium in Liquid Ammonia02:10

Reduction of Alkynes to trans-Alkenes: Sodium in Liquid Ammonia

10.9K
Alkynes can be reduced to trans-alkenes using sodium or lithium in liquid ammonia. The reaction, known as dissolving metal reduction, proceeds with an anti addition of hydrogen across the carbon–carbon triple bond to form the trans product. Since ammonia exists as a gas (bp = −33°C) at room temperature, the reaction is carried out at low temperatures using a mixture of dry ice (sublimes at −78°C) and acetone. 
When dissolved in liquid ammonia, an alkali metal, such as sodium,...
10.9K
Nitriles to Amines: LiAlH4 Reduction00:55

Nitriles to Amines: LiAlH4 Reduction

5.1K
Nitriles are reduced to amines in the presence of strong reducing agents like lithium aluminum hydride through a typical nucleophilic acyl substitution. The reaction requires two equivalents of the reducing agent. The reducing agent acts as a source of hydride ions.
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
5.1K
Rate-Determining Steps03:08

Rate-Determining Steps

39.4K
Relating Reaction Mechanisms
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
39.4K
Ladder Diagrams: Complexation Equilibria01:07

Ladder Diagrams: Complexation Equilibria

678
Ladder diagrams are useful for evaluating equilibria involving metal-ligand complexes. The vertical scale of the ladder diagram represents the concentration of unreacted or free ligand, pL. The horizontal lines on the scale depict the log of stepwise formation constants for metal-ligand complexes and indicate the dominant species in all the regions.
The formation constant, K1, for the formation of Cd(NH3)2+ complex from cadmium and ammonia is 3.55 × 102. Log K1 (i.e. pNH3) is 2.55, and...
678
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism01:37

1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism

5.3K
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
5.3K
Acid Halides to Amides: Aminolysis01:07

Acid Halides to Amides: Aminolysis

4.7K
Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
4.7K

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

Creation of an air-stable surface electrene and its application to ammonia synthesis.

Nature communications·2026
Same author

Electron-rich dianion vacancies boost diazenide intermediates for efficient chemical looping ammonia synthesis.

Nature communications·2026
Same author

Electride-Induced Electronic Modulation of Ruthenium Catalyst for Highly Efficient Alkaline Hydrogen Evolution.

Advanced science (Weinheim, Baden-Wurttemberg, Germany)·2026
Same author

Exploring Ortho-Para Hydrogen Conversion Catalysts Based on Surface Electric Field Gradient.

The journal of physical chemistry letters·2026
Same author

Amphoteric Behavior of Hydrogen in Lanthanum Oxyhydrides: Correlation with Electrochemical Properties.

Journal of the American Chemical Society·2026
Same author

Promotional Effect of Mn On NH<sub>3</sub> Synthesis Over Inverse Iron Catalyst.

ChemSusChem·2026

相关实验视频

Updated: Mar 31, 2026

Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production
08:40

Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production

Published on: December 6, 2021

4.4K

在金属绝缘器转换时,通过Ru负载的电化催化剂切换氨基合成机制

Shinji Kanbara1, Masaaki Kitano2, Yasunori Inoue1

  • 1Materials and Structures Laboratory, Tokyo Institute of Technology , 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.

Journal of the American Chemical Society
|October 27, 2015
PubMed
概括

在催化剂中用电子取代氧离子可显著增加氨合成. 这种与金属绝缘体转换相关的电子转换增强了催化活性并降低了能源需求.

更多相关视频

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction
10:57

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Published on: April 10, 2018

19.4K
Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
10:39

Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction

Published on: August 23, 2018

8.4K

相关实验视频

Last Updated: Mar 31, 2026

Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production
08:40

Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production

Published on: December 6, 2021

4.4K
Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction
10:57

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Published on: April 10, 2018

19.4K
Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
10:39

Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction

Published on: August 23, 2018

8.4K

科学领域:

  • 材料科学
  • 催化剂
  • 固态化学

背景情况:

  • 氨的合成对全球粮食生产至关重要.
  • 基于的催化剂被广泛使用,但通常需要促进剂.
  • 了解催化剂的支持特性是提高性能的关键.

研究的目的:

  • 研究[Ca24Al28O64](4+) ((O(2-)) 2中氧离子的电子替代对氨合成的催化活性的影响.
  • 在Ru加载的催化剂中将电子性能与催化性能相关联.
  • 阐明金属绝缘体转换在催化中的作用.

主要方法:

  • 有 Ru 负荷的 [Ca24Al28O64] ((4+)) ((O(2-)) x ((e(-)) 2x 催化剂的合成,电子度不同 (x).
  • 电子性质的表征,包括电子度 (Ne) 和金属绝缘体过渡.
  • 对氨合成的催化活性和明显激活能量 (Ea) 的评估.

主要成果:

  • 具有低电子度的催化剂 (Ne < 1 × 10 ⋅ 21 cm ⋅ 3) 的性能差,Ea高.
  • 将一半以上的O2-) 离子替换为电子 (Ne ≈ 1 × 10^21) cm^-3) 增加了活动量,并减半了Ea.
  • 由结构松引发的金属绝缘器转换发生在Ne ≈ 1 × 10 () 厘米 () -3.

结论:

  • 支材料的电子性质,特别是电子度和金属绝缘体过渡,对氨合成催化有着关键的影响.
  • 金属绝缘体过渡点作为催化性能的边界.
  • 定制支持的电子结构是开发先进氨合成催化剂的有希望的策略.