Trimethyl borate
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| Names | |||
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| Other names trimethoxyborane, boron trimethoxide | |||
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ChemSpider |
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ECHA InfoCard | 100.004.063 | ||
EC Number | 204-468-9 | ||
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| Properties | |||
Chemical 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 to 69 °C (154 to 156 °F; 341 to 342 K) | ||
Solubility in water | decomposition | ||
| Hazards | |||
| Main hazards | flammable | ||
| Related compounds | |||
Other cations | Trimethyl phosphite Tetramethyl orthosilicate | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
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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. It is a weak Lewis acid (AN = 23, Gutmann-Beckett method). [2]
Green fire of boric acid in methanol
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:.[3][4]
- ArMgBr + B(OCH3)3 → MgBrOCH3 + ArB(OCH3)2
- ArB(OCH3)2 + 2 H2O → ArB(OH)2 + 2 HOCH3
References
^ abc 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
^ M.A. Beckett, G.C. Strickland, J.R. Holland, and K.S. Varma, "A convenient NMR method for the measurement of Lewis acidity at boron centres: correlation of reaction rates of Lewis acid initiated epoxide polymerizations with Lewis acidity", Polymer, 1996, 37, 4629–4631. doi: 10.1016/0032-3861(96)00323-0
^ Kazuaki Ishihara, Suguru Ohara, Hisashi Yamamoto (2002). "3,4,5-Trifluorophenylboronic Acid". Organic Syntheses. 79: 176.CS1 maint: Multiple names: authors list (link) .mw-parser-output cite.citationfont-style:inherit.mw-parser-output qquotes:"""""""'""'".mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:inherit;padding:inherit.mw-parser-output .cs1-lock-free abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-lock-subscription abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcolor:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em; Collective Volume, 10, p. 80
^ R. L. Kidwell, M. Murphy, and S. D. Darling (1969). "Phenols: 6-Methoxy-2-naphthol". Organic Syntheses. 49: 90.CS1 maint: Multiple names: authors list (link) ; Collective Volume, 10, p. 80
External links
- National Pollutant Inventory - Boron and compounds
- MSDS for Trimethyl Borate
- WebBook page for BC3H9O3
