Sodium methoxide is a chemical compound with the formula CH3ONa. This white solid, which is formed by the deprotonation of methanol, is a widely used reagent in industry and the laboratory. It is also a dangerously caustic base.
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||54.02 g/mol|
|Melting point||127 °C (261 °F; 400 K)|
|Boiling point||350 °C (662 °F; 623 K) (decomposition)|
|Reacts with water|
|Solubility||Soluble in ethanol, methanol|
Insoluble in hydrocarbons
|Safety data sheet||Sigma|
|GHS Signal word||Danger|
|H251, H302, H314|
|P235+410, P280, P305+351+338, P310|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation and structureEdit
Sodium methoxide is prepared by treating methanol with sodium:
- 2 Na + 2 CH
3OH → 2 CH
3ONa + H
The reaction is so exothermic that ignition is possible. The resulting solution, which is colorless, is often used as a source of sodium methoxide, but the pure material can be isolated by evaporation followed by heating to remove residual methanol. The solid hydrolyzes in water to give methanol and sodium hydroxide. Indeed, samples of sodium methoxide are often contaminated with sodium hydroxide. The compound absorbs carbon dioxide (and water vapor) from the air, thus diminishing the alkalinity of the base.
- 2 CH
3ONa + CO
2 + H
2O → 2 CH
3OH + Na
The structure, and hence the basicity, of sodium methoxide in solution depends on the solvent. It is a significantly stronger base in DMSO where it is more fully ionized and free of hydrogen bonding.
Sodium methoxide is a routinely used base in organic chemistry, applicable to the synthesis of numerous compounds ranging from pharmaceuticals to agrichemicals. As a base, it is employed in dehydrohalogenations and various condensations. It is also a nucleophile for the production of methyl ethers.
Sodium methoxide is used as an initiator of anionic addition polymerization with ethylene oxide, forming a polyether with high molecular weight. Biodiesel is prepared from vegetable oils and animal fats, that is, fatty acid triglycerides, by transesterification with methanol to give fatty acid methyl esters (FAMEs). This transformation is catalyzed by sodium methoxide.
The ratings for this substance vary widely.
|Source||State of Connecticut||DuPont||Pharmco AAPR||ScienceLab(Both ratings on same sheet)|
- Chandran, K.; Kamruddin, M.; Ajikumar, P.K.; Gopalan, A.; Ganesan, V. (2006). "Kinetics of thermal decomposition of sodium methoxide and ethoxide". Journal of Nuclear Materials. 358 (2–3): 111–128. doi:10.1016/j.jnucmat.2006.07.003. ISSN 0022-3115.
- Sigma-Aldrich Co., Sodium methoxide. Retrieved on 2018-05-24.
- E. Weiss (1964). "Die Kristallstruktur des Natriummethylats" [The Crystal Structure of Sodium Methylate]. Zeitschrift für Anorganische und Allgemeine Chemie (in German). 332 (3–4): 197–203. doi:10.1002/zaac.19643320311.
- Y. El-Kattan; J. McAtee; B. Bessieres (2006). "Sodium Methoxide". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.rs089m.pub2.
- O. E. Curtis, Jr., J. M. Sandri, R. E. Crocker, H. Hart (1958). "Dicyclopropyl ketone". Organic Syntheses. 38: 19. doi:10.15227/orgsyn.038.0019.CS1 maint: multiple names: authors list (link); Collective Volume, 4, p. 278
- F. Reverdin (1927). "3,5-Dinitroanisole". Organic Syntheses. 7: 28. doi:10.15227/orgsyn.007.0028.; Collective Volume, 1, p. 219
- "The Code Officials Perspective" (PDF).
- "DuPont Material Safety Data Sheet" (PDF).
- "Pharmco AAPR Material Safety Data Sheet" (PDF).
- "ScienceLab Material Safety Data Sheet".