CAS 16940-66-2 Sodium Borohydride For Plastic Industry Vesicant

CAS 16940-66-2 Sodium Borohydride Manufcturer For Plastic Industry Vesicant

Details :

Name:Sodium borohydride
EINECS:241-004-4
Molecular Formula:NaBH4
Registry Number:16940-66-2
Synonyms:SBH; Sodium tetrahydroborate; Sodiumborohydridepowder; Sodiumborohydrideonneutralalumina; Sodiumborohydridepellets; Sodiumborohydridetablets; Sodiumborohydridewhitepowder; Sodium tetrahydridoborate

Chemical Properties
Appearance:white crystalline powder
Molecular Weight:37.83
Density:1.07
Boiling Point:500°C
Melting Point:400℃ (dec.)
Flash Point:69℃
Storage Temperature:Store at RT.
Water solubility: 550 g/L (25 °C)
Stability:Stability Stable, but reacts readily with water (reaction may be violent). Incompatible with water, oxidizing agents, carbon dioxide, hydrogen halides, acids, palladium, ruthenium and other metal salts, glass. Flammable solid. Air-sensitive.

NaBH4 will reduce many organic carbonyls, depending on the precise conditions. Most typically, it is used in the laboratory for converting ketones and aldehydes to alcohols. It will reduce acyl chlorides, thiol esters and imines. Under typical conditions, it will not reduce esters, amides, or carboxylic acids. At room temperature, the only acid derivatives it reduces are acyl chlorides, which are exceptionally electrophilic.

Many other hydride reagents are more strongly reducing. These usually involve replacing hydride with alkyl groups, such as lithium triethylborohydride and L-Selectride (lithium tri-sec-butylborohydride), or replacing B with Al. Variations in the counterion also affect the reactivity of the borohydride.

The reactivity of NaBH4 can be enhanced or augmented by a variety of compounds. Oxidation with iodinein tetrahydrofuran gives the borane–tetrahydrofurancomplex, which can reduce carboxylic acids.Likewise, the NaBH4-MeOH system, formed by the addition of methanol to sodium borohydride in refluxing THF, reduces esters to the corresponding alcohols. Mixing water or an alcohol with the borohydride converts some of it into unstable hydride ester, which is more efficient at reduction, but the reductant will eventually decompose spontaneously to give hydrogen gas and borates. The same reaction can run also intramolecularly: an α-ketoester converts into a diol, since the alcohol produced will attack the borohydride to produce an ester of the borohydride, which then reduces the neighboring ester. The combination of NaBH4 with carboxylic acids results in the formation of acyloxyborohydride species. These can perform a variety of reductions not normally associated with borohydride chemistry, such as alcohols to hydrocarbons and nitriles to primary amines.

Coordination chemistry

BH4− is a ligand for metal ions. Such borohydride complexes are often prepared by the action of NaBH4 (or the LiBH4) on the corresponding metal halide. One example is the titanocene derivative:

2 (C5H5)2TiCl2 + 4 NaBH4 → 2 (C5H5)2TiBH4 + 4 NaCl + B2H6 + H2

Hydrogen source

In the presence of metal catalysts, sodium borohydride releases hydrogen. Exploiting this reactivity, sodium borohydride is used in prototypes of the direct borohydride fuel cell. The hydrogen is generated for a fuel cell by catalytic decomposition of the aqueous borohydride solution:

NaBH4 + 2 H2O → NaBO2 + 4 H2 (ΔH < 0)

Applications

The principal application of sodium borohydride is the production of sodium dithionite from sulfur dioxide: Sodium dithionite is used as a bleaching agent for wood pulp and in the dyeing industry.

Sodium borohydride reduces aldehydes and ketones to give the related alcohols. This reaction is used in the production of various antibiotics includingchloramphenicol, dihydrostreptomycin, and thiophenicol. Various steroids and vitamin A are prepared using sodium borohydride in at least one step.

Sodium borohydride is used as reducing agent in the synthesis of gold nanoparticles.

Sodium borohydride has been considered as a solid state hydrogen storage candidate. Although practical temperatures and pressures for hydrogen storage have not been achieved, in 2012 a core–shell nanostructure of sodium borohydride was used successfully to store, release and reabsorb hydrogen under moderate conditions.

Safety

Sodium borohydride is a source of basic borate salts which can be corrosive, and hydrogen or diborane, which are both flammable. Spontaneous ignition can result from solution of sodium borohydride in dimethylformamide.

CAS 16940-66-2 Sodium Borohydride Manufcturer For Plastic Industry Vesicant