Methylrhenium trioxide
From Wikipedia, the free encyclopedia
| methylrhenium trioxide | |
|---|---|
 |
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| Other names | methyltrioxorhenium |
| Identifiers | |
| CAS number | [70197-13-6] |
| Properties | |
| Molecular formula | CH3ReO3 |
| Molar mass | 249.24 g/mol |
| Appearance | white powder |
| Melting point |
112 °C (385 K) |
| Solubility in water | highly soluble in water |
| Hazards | |
| MSDS | External MSDS |
| S-phrases | S22, S23, S24/25 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Methylrhenium trioxide, also known as methyltrioxorhenium, is an organometallic compound with the formula CH3ReO3. It is an odorless white powder. Methylrhenium trioxide is used as a catalyst for some organic reactions. In this compound, Re has a tetrahedral coordination environment with one methyl and three oxo ligands. The oxidation state of rhenium is +7.
[edit] Synthesis
Methylrhenium trioxide is commercially available. It may be prepared when a perrhenate (M[ReO4]n, n = 1, 2 and M = Ag+, K+, Na+, Zn+, Ca+, NH4+; (CH3)3SnReO4) is treated with chlorotrimethylsilane and tetramethyltin. If poorly soluble perrhenates are used, the addition of one equivalent of H2SO4 is recommended.[1]
[edit] Uses
Methylrhenium trioxide serves as a heterogenous catalyst for a variety of transformations. Supported on Al2O3/SiO2, it catalyzes olefin metathesis at 25 °C.
Methylrhenium trioxide can be used as a catalyst for the oxidation of alkynes with hydrogen peroxide. Under this reaction, terminal alkynes yield the corresponding acid or ester and internal alkynes yield diketones.
Methylrhenium trioxide is used as a catalyst for the epoxidation of alkenes with H2O2. Typical solvents include water, tetrahydrofuran and t-butyl alcohol.
Methylrhenium trioxide is also used as a catalyst for the conversion of aldehydes and diazoalkanes into an alkene.[2]
[edit] References
- ^ Herrmann, W. A.; Kratzer R. M.; Fischer R. W. Alkylrhenium Oxides from Perrhenates: A New, Economical Access to Organometallic Oxide Catalysts (1997). "{{{title}}}". Angew. Chem. Int. Ed. Engl. 36 (23): 2652–2654. doi:.
- ^ Hudson, A. “Methyltrioxorhenium” Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons: New York, 2002.
