Sodium borohydride
IUPAC name	Sodium tetrahydridoborate
Identifiers
CAS number	[16940-66-2]
Properties
Molecular formula	NaBH4
Molar mass	37. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 83 g/mol
Density	1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 0740 g cm-3
Melting point	400 °C[1]
Boiling point	500 °C (dec. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid )[1]
Hazards
NFPA 704	1 2 2 W
Related compounds
Other anions	Sodium cyanoborohydride Sodium hydride Sodium borate Borax
Other cations	Lithium borohydride
Related compounds	Lithium aluminium hydride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Sodium borohydride, also known as sodium tetrahydroborate, has the chemical formula NaBH₄. Symbolism The four divisions are typically color-coded with blue indicating level of Health Hazard, red indicating An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Sodium cyanoborohydride ( Na[[Boron B]] H3 ( C[[Nitrogen N]] is a Chemical compound. Sodium hydride is the Chemical compound with the formula NaH It is primarily used as a strong base in Organic synthesis. Borax (from Persian burah) also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important Boron Borax (from Persian burah) also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important Boron An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Lithium borohydride (LiBH4 is known in organic synthesis as a Reducing agent for Esters It is also renowned for one of the highest Energy Lithium aluminium hydride ( Li[[Aluminium Al]] H4) commonly abbreviated to LAH, is a Reducing agent used in Organic synthesis In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 This white solid, usually encountered as a powder, is a specialty reducing agent used in the manufacture of pharmaceuticals and other organic and inorganic compounds. A reducing agent (also called a reductant or reducer) is the element or a compound in a Redox (reduction-oxidation reaction (see Electrochemistry Pharmacology (from Greek grc φάρμακον pharmakon, "drug" and grc -λογία -logia) is the study of how Drugs It is soluble in methanol and water, but reacts with both in the absence of base. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. ^[2]

The compound was discovered in the 1940's by H. I. Schlessinger, who led a team that developed metal borohydrides for wartime applications. Hermann Irving Schlesinger ( October 11, 1882 - October 3, 1960) was an American inorganic chemist, working in Boron ^[3]

Contents 1 Synthesis and handling 2 Reactivity 2.1 Organic synthetic applications 2.2 Related reagents 2.3 Other reactions 3 Fuel cells 4 See also 5 References 6 External links

Synthesis and handling

Sodium borohydride is prepared by the reaction of sodium hydride on trimethylborate at 250-270°C:

B(OCH₃)₃ + 4 NaH → NaBH₄ + 3 NaOCH₃

It can also be generated by the action of NaH on powdered borosilicate glass. Sodium hydride is the Chemical compound with the formula NaH It is primarily used as a strong base in Organic synthesis. Trimethyl borate, or boron trimethoxide, has formula B(OCH33 It is a clear liquid Borosilicate glass is a type of Glass with the main glass-forming constituents Silica and Boron oxide. ^[4]

NaBH₄ can be recrystallized by dissolving in warm (50 °C) diglyme followed by cooling the solution. Diglyme, or bis(2-methoxyethyl ether is a Solvent with a high Boiling point. ^[5]

Reactivity

Organic synthetic applications

Sodium borohydride reduces aldehydes and ketones into alcohols, as well as the more reactive carboxylic acid derivatives acyl chlorides and thiol esters. Organic reductions or organic oxidations or organic redox reactions are Redox reactions that take place with Organic compounds In Organic An aldehyde is an organic compound containing a terminal Carbonyl group. A ketone (pronounced as key tone) is either the Functional group characterized by a Carbonyl group (O=C linked to two other Carbon atoms or In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon In Organic chemistry, an acyl chloride (or acid chloride) is an Organic compound which is a reactive derivative of a Carboxylic acid. Thioesters are compounds resulting from the bonding of Sulfur with an Acyl group with the general formula R-S-CO-R'. However, unlike the powerful reducing agent lithium aluminium hydride, sole use of NaBH₄ with gentle reaction conditions will not reduce esters, amides, or carboxylic acids. Lithium aluminium hydride ( Li[[Aluminium Al]] H4) commonly abbreviated to LAH, is a Reducing agent used in Organic synthesis Esters are a class of Chemical compounds and Functional groups Esters consist of an inorganic or organic Acid in which at least In Chemistry, an amide is one of three kinds of Compounds (sometimes called acid amide the organic Functional group characterized Carboxylic acids are Organic acids characterized by the presence of a Carboxyl group, which has the formula -C(=OOH usually written -COOH or -CO2H ^[6] An example of the use of sodium borohydride is the industrial production of fexofenadine which includes a reduction step^[7]:

Related reagents

The activity of borohydride reducing agents can be attenuated by stabilising the boron-hydride bond. Fexofenadine hydrochloride (brand names include Allegra and Telfast) is an Antihistamine drug used in the treatment of Hayfever This is done through attaching sterically bulky groups or electron withdrawing groups. Acetyl (sodium triacetoxyborohydride, (NaBH(OCOCH₃)₃) or cyano (sodium cyanoborohydride (NaCNBH₃)) groups have been used for such a purpose. Sodium cyanoborohydride ( Na[[Boron B]] H3 ( C[[Nitrogen N]] is a Chemical compound. As a result, they find use in the reductive amination reaction. Reductive amination (also known as Reductive alkylation) is a Chemical reaction which involves the conversion of a Carbonyl group to an Amine Here, the imine intermediate must be selectively reduced in the presence of the aldehyde or ketone starting material.

Stronger reducing agents can be generated by destabilising the boron-hydride bond. This is found in compounds such as superhydride (Lithium triethylborohydride) and L-Selectride (lithium tri-sec-butylborohydride). Lithium triethylborohydride ( Li[[Ethyl group|Et3]] B[[Hydride H]] commonly abbreviated to LiTEBH or Superhydride, is a powerful L-selectride, is an Organic compound. It is used in Organic chemistry as a Reducing agent, for example in the reduction of a Ketone, as part ^[8]

Other reactions

Oxidation of NaBH₄ with iodine in tetrahydrofuran creates the BH₃-THF complex, which can reduce esters. Ball-and-stick models and Space-filling models (also known as Calotte models) are 3D or spatial Molecular models which serve to display the structure Iodine (ˈaɪədaɪn ˈaɪədɪn or /ˈaɪədiːn/ from ιώδης iodes "violet" is a Chemical element that has the symbol I and Atomic "THF" redirects here For other uses see THF (disambiguation. Diborane is the Chemical compound with the formula B2H6 It is a colorless gas at room temperature with a repulsively sweet odor "THF" redirects here For other uses see THF (disambiguation. Likewise the NaBH₄-MeOH system, formed by the addition of methanol to sodium borohydride in refluxing THF reduces esters to the corresponding alcohols for instance benzyl benzoate to benzyl alcohol. Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a Chemical compound Benzyl benzoate is the Organic compound with the formula C6H5CH2O2CC6H5 Benzyl alcohol is an Organic compound with the formula C6H5CH2OH ^[9]

BH₄⁻ is an excellent ligand for metal ions. In Chemistry, a ligand is either an Atom, Ion, or Molecule (see also Functional group) that bonds to a central metal generally Such borohydride complexes are often prepared by the action of NaBH₄ (or the LiBH₄) on the corresponding metal halide, e. g. Zr(BH₄)₄.

Fuel cells

For more details on this topic, see Direct borohydride fuel cell. Direct borohydride fuel cells (DBFCs are a subcategory of Alkaline fuel cells that use a solution of Sodium borohydride for fuel

Sodium borohydride is also used in experimental fuel cell systems. A fuel cell is an electrochemical conversion device It produces electricity from Fuel (on the Anode side and an oxidant (on the As a fuel it is less flammable and less volatile than gasoline but more corrosive. It is relatively environmentally friendly because of the low toxicity of borates. The hydrogen is generated for a fuel cell by catalytic decomposition of the aqueous borohydride solution:

NaBH₄ + 2H₂O → NaBO₂ + 4H₂

See also

• Lithium borohydride

References

External links

• Material Safety Data Sheet
• National Pollutant Inventory - Boron and compounds
• Hydrogen Storage via Sodium Borohydride, Millennium Cell inc. (PDF)
• Materials & Energy Research Institute Tokyo, Ltd.
• Chemo- and stereoselectivity using Borohydride reagents

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