Sodium borohydride
[CAS# 16940-66-2]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Boride, borate and perborate
• Name: Sodium borohydride
• Synonyms: Sodium tetrahydroborate
• Molecular Formula: NaBH₄
• Molecular Weight: 37.83
• CAS Registry Number: 16940-66-2
• EC Number: 241-004-4
• SMILES: [BH4-].[Na+]

Properties

• Density: 1.07
• Melting point: 400 °C (dec.)
• Flash point: 69 °C
• Water solubility: 550 g/L (25 °C)

Safety Data

• Hazard Symbols: GHS02;GHS05;GHS06;GHS07;GHS08 Danger
• Risk Statements: H260-H301-H311-H314-H318-H332-H360
• Safety Statements: P203-P223-P231+P232-P260-P261-P262-P264-P264+P265-P270-P271-P280-P301+P316-P301+P330+P331-P302+P335+P334-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P318-P321-P330-P361+P364-P363-P370+P378-P402+P404-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	3	H301
Substances or mixtures which in contact with water emit flammable gases	Water-react.	1	H260
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1C	H314
Reproductive toxicity	Repr.	1B	H360
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	3	H311
Acute toxicity	Acute Tox.	4	H332
Acute toxicity	Acute Tox.	1	H330
Acute toxicity	Acute Tox.	3	H332
Skin corrosion	Skin Corr.	1	H314
Skin corrosion	Skin Corr.	1A	H314
Reproductive toxicity	Repr.	1B	H360FD
Acute toxicity	Acute Tox.	2	H330
Acute toxicity	Acute Tox.	3	H331
Reproductive toxicity	Repr.	1B	H360F
Substances or mixtures which in contact with water emit flammable gases	Water-react.	2	H261

• Transport Information: UN 1426

Discovery and Applications

Sodium borohydride (NaBH4) is a powerful reducing agent that is widely used in chemical synthesis and industrial applications. Sodium borohydride was first synthesized by Herbert C. Brown at the University of Chicago in the early 1940s. Brown's research on borohydrides led to the discovery of NaBH4, a breakthrough that earned him the 1979 Nobel Prize in Chemistry. This discovery provided chemists with a milder and more versatile reducing agent than earlier methods.

NaBH4 is ??a white crystalline powder that is stable under normal conditions but reacts violently with water to release hydrogen gas. Its key property is its ability to donate hydrogen ions (H?), which facilitates the reduction of various functional groups such as aldehydes, ketones, and nitro compounds to their corresponding alcohols and amines.

Sodium borohydride is essential in synthetic organic chemistry. It is used for the reduction of aldehydes and ketones. NaBH4 is ??effective in reducing these carbonyl compounds to alcohols, which is essential for the synthesis of various pharmaceuticals, fragrances, and intermediates. NaBH4 is ??the reducing agent of choice due to its selectivity and mild reaction conditions, making it ideal for the production of primary and secondary alcohols. Sodium borohydride is used in combination with other reagents to convert ketones and aldehydes to amines, a key step in the synthesis of many biologically active molecules.

In addition to its use in laboratory synthesis, sodium borohydride is also used in the pulp and paper industry. Sodium borohydride is used to bleach pulp, which reduces environmental impact compared to chlorine-based methods. NaBH4 is ??used in the production of various pharmaceuticals, where its selectivity can increase the yield and purity of active pharmaceutical ingredients (APIs). Sodium borohydride can be used as a reducing agent to remove heavy metals and other contaminants from industrial wastewater.

While sodium borohydride is a valuable reagent, it requires careful handling. It reacts with water and acids to produce flammable hydrogen gas. Proper storage under dry conditions and handling under inert gas is essential to prevent hazardous reactions. Personal protective equipment (PPE) and safety procedures are essential to safely manage its reactivity.

References

2018. From alkylarenes to anilines via site-directed carbon-carbon amination. Nature Chemistry, 11(1).
DOI: 10.1038/s41557-018-0156-y

2018. ‘Green’ synthesis of metals and their oxide nanoparticles: applications for environmental remediation. Journal of Nanobiotechnology, 16(1).
DOI: 10.1186/s12951-018-0408-4

2020. Amperometric hydrazine sensor based on the use of a gold nanoparticle-modified nanocomposite consisting of porous polydopamine, multiwalled carbon nanotubes and reduced graphene oxide. Microchimica Acta, 187(1).
DOI: 10.1007/s00604-019-4014-4