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 Alkenes: Catalytic Hydrogenation02:13

Reduction of Alkenes: Catalytic Hydrogenation

14.0K
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...
14.0K
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation02:17

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

3.9K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.9K
Hydrogen Bonds00:26

Hydrogen Bonds

133.1K
Hydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.
Hydrogen Bonds Control the World!
Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are unequally shared....
133.1K
Hydrogen Bonds01:04

Hydrogen Bonds

14.1K
A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another polar molecule, such as water (H2O), hydrogen fluoride (HF), or ammonia (NH3). The huge electronegativity difference between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom...
14.1K
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation02:24

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

9.0K
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.
9.0K
Solvents01:12

Solvents

71.0K
A solvent is a substance, most often a liquid, that can dissolve other substances. Here, the substance being dissolved is called a solute. When a solvent and a solute combine, they form a solution - a homogenous mixture of both the solvent and the solute. Water is a universal biological solvent. Its polar structure allows it to dissolve many other polar compounds. The ability of water to dissolve is governed by a balance between water molecules binding to each other and binding to the solute.
A...
71.0K

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

Inside-Out, Dual Light-, and pH-Triggered Release from Oil-Core Microcapsules Via CATCH Cleavage Mechanism.

ACS macro letters·2026
Same author

Reaction Pathways in the (De)hydrogenation of N-Heterocyclic Liquid Hydrogen Carriers Over Supported Pd Catalysts.

ChemSusChem·2026
Same author

Catalyst Potential Prescribes Intermediate Coverages in Thermocatalytic Gluconic Acid Oxidation on Pt Nanoparticles.

Journal of the American Chemical Society·2026
Same author

Controlled Placement of Trivalent Heteroatoms in MFI Zeolite Frameworks Using Structure-Directing Agents.

JACS Au·2026
Same author

Microcalorimetric quantification of hydrogen adsorption thermodynamics in water-solvated systems on Pt/C.

Faraday discussions·2026
Same author

Mercaptan-Mediated Ethylene Formation in Sulfur Oxidative Ethane Dehydrogenation on Iron Sulfide (FeS<sub>2</sub>) Catalysts.

ACS catalysis·2026

相关实验视频

Updated: Jan 30, 2026

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes
12:08

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Published on: June 24, 2022

4.1K

水友孔和溶剂之间的合作作用:结对化物中氧化物的催化后果

Daniel T Bregante1, Alayna M Johnson1, Ami Y Patel1

  • 1Department of Chemical and Biomolecular Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.

Journal of the American Chemical Society
|January 17, 2019
PubMed
概括
此摘要是机器生成的。

水友酸盐通过破坏水集群显著提高了氧化率和选择性. 这一发现挑战了传统的热催化理解,强调了水相互作用的作用.

更多相关视频

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

4.3K
Solvent Bonding for Fabrication of PMMA and COP Microfluidic Devices
04:54

Solvent Bonding for Fabrication of PMMA and COP Microfluidic Devices

Published on: January 17, 2017

17.2K

相关实验视频

Last Updated: Jan 30, 2026

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes
12:08

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Published on: June 24, 2022

4.1K
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

4.3K
Solvent Bonding for Fabrication of PMMA and COP Microfluidic Devices
04:54

Solvent Bonding for Fabrication of PMMA and COP Microfluidic Devices

Published on: January 17, 2017

17.2K

科学领域:

  • 催化剂
  • 材料科学
  • 物理化学

背景情况:

  • 酸盐对于使用过氧化 (H2O2) 的烯环氧化至关重要.
  • 传统上认为疏水空隙对于高催化活性和选择性至关重要.
  • 在酸盐催化过程中,醇组和水网络的作用尚不清楚.

研究的目的:

  • 为了研究醇组密度对Ti-替代的酸 (Ti-BEA) 催化性能的影响.
  • 阐明醇组影响反应速率和选择性的机制.
  • 挑战传统的观点,即疏水性空隙是高催化效率的唯一原因.

主要方法:

  • 合成了一系列的Ti-BEA催化剂,它们具有不同密度的西兰醇 ((SiOH) 4).
  • 在合成的催化剂中比较了1 - 氧化和H2O2分解的周转率.
  • 使用光谱,热力学和动力学分析来探测反应机制和过渡状态.

主要成果:

  • 最多的水性Ti-BEA催化剂的环氧化转换率是无缺陷Ti-BEA的100倍.
  • 所有西拉诺密度的H2O2分解率都相似,表明氧化过程有选择性增强.
  • 与预期相反,增加的水友性导致更高的环氧化选择性.
  • 热力学分析显示,从破坏水集群中获得有利的率可以提高氧化率.

结论:

  • 醇组及其相关的联水网络在提升Ti-BEA催化剂的氧化率和选择性方面发挥着至关重要的作用.
  • 催化增强归因于当环氧化过渡状态破坏这些水网络时实现的增强,而不是活跃位置电子的变化.
  • 这些发现为热石催化提供了新的视角,强调了反应剂,溶剂和催化剂表面之间的分子相互作用的重要性.