Sodium bis(2-methoxyethoxy)aluminumhydride

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Sodium bis(2-methoxyethoxy)aluminumhydride
Structural formula of sodium bis(2-methoxyethoxy)aluminumhydride
Identifiers
Abbreviations SMEAH
CAS number 22722-98-1 N
PubChem 16684438
ChemSpider 21169529 YesY
Jmol-3D images Image 1
Image 2
Properties
Molecular formula C6H16AlNaO4
Molar mass 202.16 g mol−1
Appearance Transparent crystals
Density 1.036 g/mL (>60% solution)
Viscosity 65.1 cps (70% solution)[citation needed]
Hazards
Main hazards Unstable toward water
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Sodium bis(2-methoxyethoxy)aluminumhydride (trade names Red-Al, Synhydrid, Vitride) is an organoaluminium compound with the formula NaAlH2(OCH2CH2OCH3)2. The trade name Red-Al refers to its being a reducing aluminium compound. It is a predominantly as a reducing agent in organic synthesis. The compound features a tetrahedral aluminium center attached to two hydride and two alkoxide groups, the latter derived from 2-methoxyethanol. Commercial solutions are colourless/pale yellow and viscous. At low temperatures, the solution solidifies to a glassy pulverizable substance.

Sodium bis(2-methoxyethoxy)aluminumhydride is a versatile hydride reducing agent. It readily converts aldehydes, ketones, carboxylic acids, esters, acyl halides, and anhydrides to primary alcohols. The cyclic compounds such a lactones and epoxides are reduced to diols. Nitrogen derivates such a amides, nitriles, imines, and most other organonitrogen compounds are reduced to the corresponding amines. Nitroarenes can be converted to azoxyarenes, azoarenes, or hydroazoarenes, depending on the reaction conditions.[1]

Some common functional group reductions using sodium bis(2-methoxyethoxy)aluminumhydride can be found below:

Red-Al Reductions.png

Comparison with lithium aluminium hydride[edit]

As a reagent, sodium bis(2-methoxyethoxy)aluminumhydride is comparable with lithium aluminum hydride (LAH, LiAlH4).

It is a safer substitute for LAH and related hydrides. Sodium bis(2-methoxyethoxy)aluminumhydride exhibits similar reducing effects, but does not have the inconvenient pyrophoric nature, short shelf-life, or limited solubility of LAH. Upon contact with air and moisture, Sodium bis(2-methoxyethoxy)aluminumhydride reacts exothermically but does not ignite, and tolerates temperatures up to 200 °C. Under dry conditions it has unlimited shelf life. It is soluble in aromatic solvents, whereas LAH is only soluble in ethers. For example, a solution greater than 60 wt.% concentration in toluene is commercially available. The reagent can be modified to effect partial reductions.[1]

References[edit]

  1. ^ a b Gugelchuk, M.; Silva, L. F. III; Vasconcelos, R. S.; Quintiliano, S. A. P. (2007). "Sodium Bis(2-methoxyethoxy)aluminum Hydride". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/9780470842898.rs049.pub2. 

External links[edit]