硫化物通过H5PV2Mo10O40聚氧甲酸盐催化的电子转移-氧转移氧化
Alexander M Khenkin1, Gregory Leitus, Ronny Neumann
1Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel 76100.
Journal of the American Chemical Society
|July 31, 2010
概括
酸性瓦纳多摩利卜酸盐通过低温电子转移-氧气转移机制催化硫化物氧化到硫氧化物. 这个过程涉及中介的基减少的多氧甲酸盐物种和沉物形成,有效地产生硫氧化物.
科学领域:
- 无机化学 无机化学
- 催化剂是一种催化剂.
- 反应机制 反应机制
背景情况:
- 硫化物氧化在化学合成和工业过程中至关重要.
- 聚氧甲酸盐 (POMs) 是具有可调节的氧化还原特性的多功能催化剂.
- 了解反应机制是优化催化效率的关键.
研究的目的:
- 为了阐明硫化物氧化催化H(5)PV(2)Mo(10)O(40的机制.
- 为了确定关键的中间体和反应途径.
- 在氧化反应中探索酸性瓦纳莫利巴达的催化潜力.
主要方法:
- 紫外线和电子磁共振 (EPR) 光谱用于中间识别.
- 红外 (IR) 光谱法用于监测产品形成.
- 晶体学用于表征反应产物.
主要成果:
- 反应通过低温电子转移-氧转移 (ET-OT) 机制进行.
- 光谱证据证实了基减少的多氧甲酸离子对的形成.
- 观察到含有VO2+) 部分的沉物,在溶解后释放硫氧化物产物.
- 在有氧条件下,产量主要为硫氧化物 (90%) 和一些二硫化物 (10%).
结论:
- H(5)PV(2)Mo(10)O(40) 通过ET-OT机制有效催化硫化物转化为硫氧化物.
- 这项研究为POM催化氧化提供了详细的机械洞察力.
- 这种催化系统对硫氧化物形成具有很高的选择性.
相关概念视频
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
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.
Oxidation of Alkenes: Syn Dihydroxylation with Potassium Permanganate
Alkenes can be dihydroxylated using potassium permanganate. The method encompasses the reaction of an alkene with a cold, dilute solution of potassium permanganate under basic conditions to form a cis-diol along with a brown precipitate of manganese dioxide.
Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
Oxidative Cleavage of Alkenes: Ozonolysis
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.
Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...

