Sodium aluminium hydride
Encyclopedia
Sodium aluminium hydride (NaAlH4) or sodium alanate is a chemical compound
used as a reducing agent
. It is similar to lithium aluminium hydride
.
It is used for hydrogen storage
in hydrogen tank
s, the sodium tetrahydroaluminate can absorb up to 7.4 wt of hydrogen, with hydrogen released when heated at 200 °C (392 °F). absorption can be slow and take up to 15 minutes to fill a tank.
Sodium aluminium hydride is a strong reducing agent. Similar in reactivity to lithium aluminum hydride. May react violently with oxidizing agents.Its action is simailar to DIBAL in organic reactions.
LAH is the more powerful reducing agent than sodium borohydride due to the weaker Al-H bond compared to the B-H bond. The reactivity of sodium borohydride can be modified by addition of iodine or methanol in BH3-THF to reduce esters into the corresponding alcohols like the reaction of benzyl benzoate to benzyl alcohol
NaH
can be used to efficiently produce sodium aluminium hydride
(NaAlH4) by metathesis
in THF
:
By adding titanium
the kinetics of hydrogen release and recharge are improved.
Sodium aluminium hydride is highly flammable. Does not react in dry air at room temperature. Very sensitive to moisture. Ignites or explodes on contact with water or moist air.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
used as a reducing agent
Reducing agent
A reducing agent is the element or compound in a reduction-oxidation reaction that donates an electron to another species; however, since the reducer loses an electron we say it is "oxidized"...
. It is similar to lithium aluminium hydride
Lithium aluminium hydride
Lithium aluminium hydride, commonly abbreviated to LAH or known as LithAl, is an inorganic compound with the chemical formula LiAlH4. It was discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters,...
.
It is used for hydrogen storage
Hydrogen storage
Hydrogen storage describes the methods for storing H2 for subsequent use. The methods span many approaches, including high pressures, cryogenics, and chemical compounds that reversibly release H2 upon heating...
in hydrogen tank
Hydrogen tank
A Hydrogen tank is used for hydrogen storage. The first type IV hydrogen tanks for compressed hydrogen at 700 Bar were demonstrated in 2001, the first fuel cell vehicles on the road with type IV tanks are the Toyota FCHV, Mercedes-Benz F-Cell and the HydroGen4.At the hydrogen station Hamburg...
s, the sodium tetrahydroaluminate can absorb up to 7.4 wt of hydrogen, with hydrogen released when heated at 200 °C (392 °F). absorption can be slow and take up to 15 minutes to fill a tank.
Sodium aluminium hydride is a strong reducing agent. Similar in reactivity to lithium aluminum hydride. May react violently with oxidizing agents.Its action is simailar to DIBAL in organic reactions.
- RCOOR' + H2 + NaAlH4(reducing agent) → RCOOH + R'OH
LAH is the more powerful reducing agent than sodium borohydride due to the weaker Al-H bond compared to the B-H bond. The reactivity of sodium borohydride can be modified by addition of iodine or methanol in BH3-THF to reduce esters into the corresponding alcohols like the reaction of benzyl benzoate to benzyl alcohol
NaH
Sodium hydride
Sodium hydride is the chemical compound with the empirical formula NaH. It is primarily used as a strong base in organic synthesis. NaH is representative of the saline hydrides, meaning it is a salt-like hydride, composed of Na+ and H− ions, in contrast to the more molecular hydrides such as...
can be used to efficiently produce sodium aluminium hydride
Hydride
In chemistry, a hydride is the anion of hydrogen, H−, or, more commonly, a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties. In compounds that are regarded as hydrides, hydrogen is bonded to a more electropositive element or group...
(NaAlH4) by metathesis
Metathesis (chemistry)
Salt metathesis is a molecular process involving the exchange of bonds between the two reacting chemical species, which results in the creation of products with similar or identical bonding affiliations. This is represented by the general reaction scheme:These chemical species can either be ionic...
in THF
ThF
Follicular B helper T cells , are antigen-experienced CD4+ T cells found in the B cell follicles of secondary lymphoid organs such as lymph nodes, spleens and Peyer's patches, and are identified by their constitutive expression of the B cell follicle homing receptor CXCR5...
:
- LiAlH4 + NaH → NaAlH4 + LiH
By adding titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
the kinetics of hydrogen release and recharge are improved.
Sodium aluminium hydride is highly flammable. Does not react in dry air at room temperature. Very sensitive to moisture. Ignites or explodes on contact with water or moist air.