Trimethyl borate
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| Names | |||
|---|---|---|---|
| Other names
trimethoxyborane, boron trimethoxide | |||
| Identifiers | |||
121-43-7  | |||
| ChEBI | CHEBI:38913 | ||
| ChemSpider | 8157 | ||
| EC number | 204-468-9 | ||
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| Jmol-3D images | Image | ||
| PubChem | 8470 | ||
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| Properties | |||
| Molecular formula |
C3H9BO3 | ||
| Molar mass | 103.91 g·mol−1 | ||
| Appearance | colourless liquid | ||
| Density | 0.932 g/ml | ||
| Melting point | −34 °C (−29 °F; 239 K) | ||
| Boiling point | 68 °C (154 °F; 341 K) | ||
| decomposition | |||
| Hazards | |||
| Main hazards | flammable | ||
| Related compounds | |||
| Other cations |
Trimethyl phosphite Tetramethyl orthosilicate | ||
| Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | |||
verify (what is: / ?) | |||
| Infobox references | |||
Trimethyl borate is the organoboron compound with the formula B(OCH3)3. It is a colourless liquid that burns with a green flame.[1] It is an intermediate in the preparation of sodium borohydride and is a popular reagent in organic chemistry.
Borate esters are prepared by heating boric acid or related boron oxides with alcohols under conditions where water is removed.[1]
Applications
Trimethyl borate is the main precursor to sodium borohydride by its reaction with sodium hydride:
- 4 NaH + B(OCH3)3 → NaBH4 + 3 NaOCH3
It is a gaseous anti-oxidant in brazing and solder flux. Otherwise, trimethyl borate has no announced commercial applications. It has been explored as a fire retardant, as well as being examined as an additive to some polymers.[1] It is a useful reagent in organic synthesis, as a precursor to boronic acids, which are used in Suzuki couplings. These boronic acids are prepared via reaction of the trimethyl borate with Grignard reagents followed by hydrolysis:.[2][3]
- ArMgBr + B(OCH3)3 → MgBrOCH3 + ArB(OCH3)2
- ArB(OCH3)2 + 2 H2O → ArB(OH)2 + 2 HOCH3
References
- ↑ 1.0 1.1 1.2 Robert J. Brotherton, C. Joseph Weber, Clarence R. Guibert, John L. Little "Boron Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2000, Wiley-VCH. doi:10.1002/14356007.a04_309
- ↑ Kazuaki Ishihara, Suguru Ohara, Hisashi Yamamoto (2002). "3,4,5-Trifluorophenylboronic Acid". Org. Synth. 79: 176.; Coll. Vol. 10, p. 80
- ↑ R. L. Kidwell, M. Murphy, and S. D. Darling (1969). "Phenols: 6-Methoxy-2-naphthol". Org. Synth. 49: 90.; Coll. Vol. 10, p. 80