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| Names | |
|---|---|
| IUPAC name Sodium methoxide | |
| Other names Sodium methylate | |
| Identifiers | |
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3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.004.273 |
| UNII | |
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| Properties | |
| CH3NaO | |
| Molar mass | 54.02 g/mol |
| Appearance | White solid |
| Melting point | 127 °C (261 °F; 400 K) |
| Boiling point | 350 °C (662 °F; 623 K)[1] (decomposition) |
| Reacts with water | |
| Solubility | Soluble inethanol,methanol Insoluble in hydrocarbons |
| Structure | |
| Hexagonal | |
| Hazards | |
| GHS labelling: | |
   | |
| Danger | |
| H251,H302,H314[2] | |
| P235+P410,P280,P305+P351+P338,P310[2] | |
| Safety data sheet (SDS) | Sigma[2] |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Sodium methoxide is the simplestsodiumalkoxide. With the formulaCH3ONa, it is a white solid, which is formed by thedeprotonation ofmethanol. It is a widely usedreagent in industry and the laboratory. It is also a dangerously causticbase.
Sodium methoxide is prepared by treating methanol with sodium:
The reaction is soexothermic 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.
As a solid, sodium methoxide ispolymeric, with sheet-like arrays ofNa+ centers, each bonded to four oxygen centers.[3]
The structure, and hence the basicity, of sodium methoxide in solution depends on the solvent. It is a significantly stronger base inDMSO where it is more fully ionized and free ofhydrogen bonding.[4]
Sodium methoxide is a routinely used base in organic chemistry, applicable to the synthesis of numerous compounds ranging frompharmaceuticals toagrichemicals.[4] As a base, it is employed indehydrohalogenations and variouscondensations.[5] It is also anucleophile for the production ofmethylethers.[6]
Sodium methoxide is used as aninitiator ofanionic addition polymerization withethylene oxide, forming apolyether with high molecular weight.[7]Biodiesel is prepared from vegetable oils and animal fats (fatty acid triglycerides) bytransesterification with methanol to givefatty acid methyl esters (FAMEs). Sodium methoxide acts as a catalyst for this reaction, but will combine with anyfree fatty acids present in the oil/fat feedstock to formsoap byproducts.[citation needed]
The solid hydrolyzes in water to give methanol andsodium hydroxide. Indeed, samples of sodium methoxide are often contaminated with sodium hydroxide, which is difficult to detect. The compound absorbscarbon dioxide from the air to form methanol andsodium carbonate, thus diminishing the alkalinity of the base.[citation needed]
Commercial batches of sodium methoxide show variable levels of degradation, and were a major source of irreproducibility when used inSuzuki reactions.[8]
Sodium methoxide is highlycaustic and reacts with water to givemethanol, which is toxic and volatile.
The ratings for this substance vary widely.
| Rating | |||||
|---|---|---|---|---|---|
| Source | State of Connecticut[9] | DuPont[10] | Pharmco AAPR[11] | ScienceLab[12](Both ratings on same sheet) | |
