Sodium Borohydride (NaBH4) is a white crystalline powder used as a reducing agent in organic synthesis and as a hydrogen source for fuel cells. It is highly reactive and water-sensitive.
| IUPAC Name | Sodium Tetrahydroborate |
| Molecular Formula | NaBH4 |
| CAS Number | 16940-66-2 |
| Synonyms | Sodium Borohydride, Sodium Tetrahydridoborate, Sodium Borohydride Hydrate, Sodium Tetrahydroborate Hydrate |
| InChI | InChI=1S/BH4.Na/h1H4;/q+1;-1 |
Sodium Borohydride Properties
Sodium Borohydride boiling point
Sodium Borohydride does not have a well-defined boiling point as it decomposes upon heating. The decomposition temperature depends on the temperature and pressure conditions.
Sodium Borohydride melting point
Sodium Borohydride has a melting point of 240-242°C. At this temperature, the solid form of NaBH4 transitions to a liquid state.
Sodium Borohydride density g/ml
The density of Sodium Borohydride is 1.33 g/ml. It is a white crystalline solid that is relatively dense compared to other substances.
Sodium Borohydride molar mass
The molar mass of Sodium Borohydride (NaBH4) is 37.83 g/mol. It is calculated by adding the atomic masses of all the atoms present in the molecular formula of NaBH4 (1 sodium atom, 1 boron atom, and 4 hydrogen atoms).
Sodium Borohydride molecular weight
The molecular weight of Sodium Borohydride is 37.83 g/mol. This is the sum of the atomic masses of the individual atoms in the molecular formula of NaBH4.
Sodium Borohydride Structure
Sodium Borohydride is a tetrahedral molecule with a sodium ion at the center and four boron hydride groups attached to it. The boron atom is bonded to four hydrogen atoms, creating a tetrahedral structure.
Sodium Borohydride formula
The chemical formula of Sodium tetrahydroborate is NaBH4. It is composed of one sodium (Na) atom, one boron (B) atom, and four hydrogen (H) atoms. This formula represents the chemical composition of this substance and its elemental makeup.
| Appearance | White crystalline powder |
| Specific Gravity | 1.33 g/ml |
| Color | White |
| Odor | Odorless |
| Molar Mass | 37.83 g/mol |
| Density | 1.33 g/ml |
| Melting Point | 240-242°C |
| Boiling Point | Decomposes upon heating |
| Flash Point | Not applicable |
| Water Solubility | Soluble in water |
| Solubility | Soluble in organic solvents |
| Vapor Pressure | Not applicable |
| Vapor Density | Not applicable |
| pKa | Not applicable |
| pH | Not applicable |
Sodium Borohydride Safety and Hazards
Sodium tetrahydroborate is flammable and reactive with water. It can release hydrogen gas, which is flammable and can form explosive mixtures with air. Sodium tetrahydroborate is also a skin and eye irritant. Adequate ventilation and personal protective equipment must be used to minimize exposure while handling Sodium tetrahydroborate. Store it in a cool, dry place away from ignition sources and water.
| Hazard Symbols | Flammable, Irritant |
| Safety Description | S26, S36/37 |
| UN IDs | UN3375 |
| HS Code | 2827.90.90 |
| Hazard Class | 4.3 |
| Packing Group | II |
| Toxicity | Moderately toxic by ingestion, inhalation, and skin contact |
Sodium Borohydride Synthesis Methods
Sodium Borohydride (NaBH4) can be synthesized through several methods including:
- Sodium Metal Reduction: This method involves the reduction of boron trioxide (B2O3) with sodium metal to produce NaBH4.
- Sodium Hydride Reduction: Sodium hydride (NaH) can be used to reduce boron trihalides to produce NaBH4.
- Lithium Aluminum Hydride Reduction: Lithium aluminum hydride (LiAlH4) can be used to reduce boron halides to produce NaBH4.
- Hydrogenation: Sodium borohydride can be synthesized by the hydrogenation of sodium borohydride hydride (NaBH3H).
Specialized equipment and trained personnel in a well-ventilated environment must carry out all these methods because Sodium tetrahydroborate is flammable and reactive. The synthesis method selected will depend on the desired yield, purity, and cost considerations.
Sodium Borohydride Uses
Sodium tetrahydroborate (NaBH4) is a versatile reducing agent and has a wide range of applications in various fields. Some of the common uses of Sodium tetrahydroborate are:
- Organic Synthesis: NaBH4 is used in the reduction of carbonyl compounds, esters, nitriles, and amides to their corresponding alcohols, aldehydes, and amines.
- Pharmaceuticals: Sodium tetrahydroborate is used in the synthesis of various active pharmaceutical ingredients and in the preparation of chiral compounds.
- Polymer Science: NaBH4 is used in the reduction of epoxy resins and unsaturated polyester resins.
- Environment: Sodium tetrahydroborate can be used in the treatment of wastewater to reduce pollutants such as heavy metals and dyes.
- Food Industry: NaBH4 is used as a reducing agent in the production of low-fat spreads, ice cream, and chocolate.
Overall, Sodium tetrahydroborate has proven to be a valuable tool in the field of chemical synthesis due to its mild reducing properties and ability to selectively reduce functional groups in complex molecular structures.
Questions:
Which of these compounds can be reduced by sodium borohydride? check any and all that apply.
Sodium tetrahydroborate (NaBH4) can reduce a wide range of compounds, including:
- Carbonyl compounds, such as aldehydes and ketones
- Nitriles
- Esters
- Amides
- Epoxy resins
- Unsaturated polyester resins
- Certain dyes
- Heavy metals
- Chiral compounds
It is important to note that the specific conditions and reaction parameters can affect the efficiency of the reduction and the selectivity of the reduction process. Also, not all compounds are suitable for reduction with sodium tetrahydroborate, as some may undergo unwanted side reactions.
Why is it important to exposing sodium borohydride to moisture?
Exposure of sodium tetrahydroborate (NaBH4) to moisture is important for several reasons:
- Reactivity: Sodium tetrahydroborate is highly reactive and can decompose rapidly in the presence of moisture, generating hydrogen gas and heat. This can pose a risk of explosion and fire if not handled properly.
- Hydrolysis: Sodium tetrahydroborate readily hydrolyzes in the presence of moisture to form sodium tetrahydroborate hydrate (NaBH4.xH2O), which has reduced reducing properties compared to the anhydrous form.
- Storage Stability: Moisture can cause the gradual decomposition of sodium tetrahydroborate, reducing its shelf life and effectiveness as a reducing agent.
Therefore, it is important to store sodium borohydride in a dry and airtight container, and to handle it in a well-ventilated environment to minimize exposure to moisture. If moisture exposure is unavoidable, the use of moisture-scavenging agents or protective atmospheres can help to minimize its effects on the stability and reactivity of sodium tetrahydroborate.
Is sodium borohydride a catalyst?
Sodium tetrahydroborate (NaBH4) is not typically considered a catalyst, but rather a reducing agent. A catalyst is a substance that speeds up a chemical reaction without undergoing a permanent change itself. Sodium tetrahydroborate transforms chemically as it reduces, consuming itself in the reduction reaction.
Organic synthesis and reduction reactions commonly use sodium tetrahydroborate as a source of hydride ions (H-). Sodium tetrahydroborate transfers these hydride ions to the substrate molecule, reducing functional groups such as carbonyls, nitriles, and esters. Despite its role as a reducing agent, sodium tetrahydroborate may play a secondary role as a proton acceptor, making it a mild base that can influence the reaction conditions and affect the outcome of the reaction.
What flammable gas is produced if sodium borohydride is mixed with water?
If sodium tetrahydroborate (NaBH4) is mixed with water, it undergoes rapid hydrolysis to form sodium borohydride hydrate (NaBH4.xH2O) and hydrogen gas. The hydrogen gas produced is flammable and can pose a risk of explosion and fire if not handled properly.
The reaction between sodium tetrahydroborate and water can be exothermic and generate heat, which can further accelerate the rate of hydrolysis and increase the release of hydrogen gas. The reaction can also generate a large volume of gas in a short period of time, creating a risk of over-pressurization and explosion.
Therefore, it is important to handle sodium tetrahydroborate in a well-ventilated environment and to avoid exposing it to moisture or water. If exposure to moisture is unavoidable, the use of moisture-scavenging agents or protective atmospheres can help to minimize the rate of hydrolysis and the release of hydrogen gas.
How many moles of camphor react with sodium borohydride?
The number of moles of camphor that will react with sodium tetrahydroborate (NaBH4) depends on several factors, including the stoichiometry of the reaction, the concentration and purity of the reactants, and the reaction conditions. The stoichiometry of the reaction can be determined from the chemical equation for the reduction of camphor to isoborneol using sodium tetrahydroborate:
C10H16O + 4 NaBH4 → C10H18O + 4 NaBO2 + 4 H2
From the equation, one mole of camphor reacts with 4 moles of sodium tetrahydroborate. The actual amount of camphor that will react with a given amount of NaBH4 will depend on the concentration and purity of the reactants, as well as the reaction conditions such as temperature, time, and catalyst.
Therefore, without more specific information, it is not possible to determine the exact number of moles of camphor that will react with sodium tetrahydroborate.