Methyltrioxorhenium
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| Surname | Methyltrioxorhenium | ||||||||||||
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| Molecular formula | CH 3 ReO 3 | ||||||||||||
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| Molar mass | 249.24 g mol −1 | ||||||||||||
| Physical state |
firmly |
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| Melting point |
111 ° C |
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| solubility |
soluble in water (50 g / l) and organic solvents |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | |||||||||||||
Methyltrioxorhenium (MTO) is a chemical compound of rhenium . It is one of the organometallic compounds . Methyltrioxorhenium can be used as a catalyst in a variety of organic chemistry reactions.
Extraction and presentation
The starting point for the production of methyltrioxorhenium is usually rhenium (VII) oxide . This is converted to methyltrioxorhenium with organic tin compounds such as tetramethyltin .
- THF = tetrahydrofuran , solvent, Me = methyl
Since the rhenium (VII) oxide is not completely converted to MTO in this synthesis and toxic organic tin compounds are required for this synthesis, alternatives were sought. A possible alternative is the reaction of silver perrhenate with acetyl chloride and methyl zinc acetate .
properties
Physical Properties
Methyltrioxorhenium is very stable in comparison with other organometallic compounds. It can be sublimated without decomposition and only decomposes at temperatures> 300 ° C. Sublimated methyltrioxorhenium crystallizes in characteristic needles.
Chemical properties
Methyltrioxorhenium does not react with water , oxygen or organic solvents at room temperature . A gold-colored polymeric solid with octahedrally coordinated metal centers forms in warm water .
use
Methyltrioxorhenium serves as a catalyst in several reactions in organic chemistry. It catalyzes the oxidation of olefins with the help of hydrogen peroxide to epoxides . MTO initially forms a peroxo complex with hydrogen peroxide . An oxygen atom is then transferred from this to the olefin and the epoxide is formed.
Another reaction that is catalyzed by methyltrioxorhenium is the conversion of aldehydes with triphenylphosphine and diazo compounds to form olefins. It is also possible to carry out metathesis reactions with the aid of methyltrioxorhenium, which has been applied to aluminum oxide, as a catalyst.
Individual evidence
- ↑ a b Data sheet methyltrioxorhenium (VII) from Sigma-Aldrich , accessed on October 16, 2016 ( PDF ).
- ^ FE Kühn, R. Fischer, W. Herrmann : Methyltrioxorhenium. In: Chemistry in Our Time . 1999, 33, pp. 192-198, doi : 10.1002 / ciuz.19990330403 .
- ^ WA Herrmann, AMJ Rost, JKM Mitterpleininger, N. Szesni, S. Sturm, RW Fischer, FE Kühn: Inexpensive, efficient and environmentally friendly synthesis of the versatile catalyst methyltrioxorhenium (MTO) , in: Angew. Chem. 2007, 119, pp. 7440-7442, doi : 10.1002 / anie.200703017 .
literature
- FE Kühn, R. Fischer, W. Herrmann : Methyltrioxorhenium. In: Chemistry in Our Time . 1999, 33, pp. 192-198, doi : 10.1002 / ciuz.19990330403 .
- F. Kühn, A. Scherbaum, W. Herrmann: Methyltrioxorhenium and its applications in olefin oxidation, metathesis and aldehyde olefination. In: Journal of Organometallic Chemistry . 2004, 689, pp. 4149-4164, doi : 10.1016 / j.jorganchem.2004.08.018 .
- AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1634.