Name | Sodium borohydride |
Synonyms | SBH 1H-borole VenPure? SF Sodium borohydride sodium boron(-1) anion Sodiumborohydridepowder Sodium tetrahydroborate Sodiumborohydridepellets Sodiumborohydridetablets Sodium tetrahydridoborate Sodiumborohydridewhitepowder Sodiumborohydrideonneutralalumina SodiuM borohydride solution 2.0 M in triethylene glycol diMethyl ether |
CAS | 16940-66-2 |
EINECS | 241-004-4 |
InChI | InChI=1/C4H5B/c1-2-4-5-3-1/h1-5H |
InChIKey | YOQDYZUWIQVZSF-UHFFFAOYSA-N |
Molecular Formula | BH4Na |
Molar Mass | 37.83 |
Density | 1.035g/mLat 25°C |
Melting Point | >300 °C (dec.) (lit.) |
Boling Point | 500°C |
Flash Point | 158°F |
Water Solubility | 550 g/L (25 ºC) |
Appearance | tablets |
Specific Gravity | 1.4 |
Color | White |
Merck | 14,8592 |
PH | 11 (10g/l, H2O, 20℃) |
Storage Condition | Store at RT. |
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 salt |
Sensitive | Hygroscopic |
Explosive Limit | 3.02%(V) |
Physical and Chemical Properties | White crystalline powder, easy to absorb moisture, flammable in case of fire |
Use | It is used as a reducing agent for aldehydes, ketones and acid chlorides, a foaming agent for plastic industry, a bleaching agent for paper making and a hydrogenating agent for manufacturing Dihydrostreptomycin in pharmaceutical industry |
Risk Codes | R60 - May impair fertility R61 - May cause harm to the unborn child R15 - Contact with water liberates extremely flammable gases R34 - Causes burns R23/24/25 - Toxic by inhalation, in contact with skin and if swallowed. R24/25 - R35 - Causes severe burns R21/22 - Harmful in contact with skin and if swallowed. R51/53 - Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. R42/43 - May cause sensitization by inhalation and skin contact. R49 - May cause cancer by inhalation R63 - Possible risk of harm to the unborn child R62 - Possible risk of impaired fertility R36/38 - Irritating to eyes and skin. R43 - May cause sensitization by skin contact R19 - May form explosive peroxides R68 - Possible risk of irreversible effects R50/53 - Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. |
Safety Description | S53 - Avoid exposure - obtain special instructions before use. S43 - In case of fire use ... (there follows the type of fire-fighting equipment to be used.) S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S43A - S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S22 - Do not breathe dust. S50 - Do not mix with ... S36/37 - Wear suitable protective clothing and gloves. S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. |
UN IDs | UN 3129 4.3/PG 3 |
WGK Germany | 2 |
RTECS | ED3325000 |
FLUKA BRAND F CODES | 10-21 |
TSCA | Yes |
HS Code | 28500090 |
Hazard Class | 4.3 |
Packing Group | I |
Toxicity | LD50 orally in Rabbit: 160 mg/kg LD50 dermal Rabbit 230 mg/kg |
Raw Materials | Methyl alcohol Sulfuric acid Sodium Orthoboric acid Hydrogen |
Downstream Products | bumetanide |
white crystalline powder. Relative density 1- 074. In dry air temperature reaches 300 ℃ or vacuum 400 ℃ is still stable, non-volatile, melting point of 505 ℃, sodium borohydride is soluble in water, liquid ammonia, amines, slightly soluble in Tetrahydrofuran, insoluble in ether, benzene, hydrocarbons. Hydrogen is produced by interaction with water. Stable in alkaline solution, in acidic solution is quickly completely decomposed. Sodium Borohydride alkaline solution is Brown yellow.
sodium borate methyl hydride method: boric acid and an appropriate amount of methanol were added to the rectification vessel, and the mixture was heated slowly and completely refluxed at 54 ° C. For 2H, and then the methyl borate and methanol azeotropes were collected. The azeotropic liquid was treated with sulfuric acid, and the pure product was obtained after rectification. Sodium hydride obtained by the interaction of hydrogen and sodium is sent to the condensation reaction tank, and is heated to about 220 ° C. With stirring to start adding methyl borate, stop heating when reaching 260 ° C. The feeding temperature was controlled to be below 280 ° C., and stirring was continued after the feeding to fully react. After cooling to below 100 ° C., centrifugal separation, condensation product cake is obtained. Add an appropriate amount of water into the hydrolyzer, slowly add the filter cake into the hydrolyzer, control the temperature below 50 ℃, raise the temperature to 80 ℃ after feeding, centrifuge and separate, the hydrolysate is sent to the stratification device, and the automatic stratification is carried out after 1H, and the lower hydrolysis solution is sodium borohydride solution.
is a good reducing agent, which is characterized by stable performance and selective reduction. It can be used as a reducing agent for aldehydes, ketones and acid chlorides, a foaming agent for plastics, a hydrogenation agent for the manufacture of dihydrostreptomycin, an intermediate for the manufacture of potassium borohydride, a raw material for the synthesis of borane, and for the paper industry and mercury-containing wastewater treatment agents. It is also a fuel cell hydrogen source carrier.
packed in an iron drum lined with a polyethylene plastic bag. 50kg net weight per barrel. It belongs to Class II water burning articles. Risk code: GB 4.3 class 43044. UNN0.1426; IMDG CODE page 4361, Class 4.3. Should be stored in a cool, dry warehouse. Moisture-proof, shock-proof, do not mix with inorganic acid storage, away from heat sources and fire and flammable items. When there is a fire, it is not possible to use a fire extinguisher with water as a reference, and it is not possible to use a carbon dioxide and carbon tetrachloride type fire extinguisher. It can only be used for fire extinguishing with powder and dry sand. After contact with sodium borohydride Laryngalgia, Cough, shortness of breath, Head Pain, Abdominal Pain, Diarrhea, dizziness, conjunctival congestion, pain and other symptoms. Should prevent dust from flying, strengthen ventilation or wear protective masks, pay attention to the protection of the eyes, wear closed protective glasses, not to eat, drink water and smoking at work. After poisoning, he left the scene quickly, took a semi-recumbent position for rest, inhaled fresh air, washed his eyes with plenty of water, took off his contaminated clothes and rinsed his whole body. When he entered the digestive tract, he immediately gargled his mouth and drank a lot of water to induce vomiting, the patient was sent to hospital for treatment.
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
quenching method | is unstable to acid and produces borane! The quenching reaction should be very careful when the amount is large. Slowly add saturated ammonium chloride solution (dilute hydrochloric acid) to quench under the ice bath. After dissolving with methanol, fully dilute with water, add acid and place. At this time, borane, which is highly toxic, easy to spontaneously ignite and easy to burn the skin, is produced, so all operations must be carried out in the fume hood, and the waste liquid is neutralized with alkali and poured into the corresponding waste liquid barrel in the floor fume hood. Borane is extremely easy to ignite spontaneously, so CO2 fire extinguishers should be prepared. |
Overview | Sodium borohydride is an inorganic compound, white to off-white fine crystalline powder or block, which quickly reacts with methanol at room temperature to form hydrogen. Strong hygroscopicity, easy to absorb water and deliquesce, boiling point 500 ℃ (vacuum); melting point 400 ℃; soluble in water and lower alcohols, liquid ammonia, insoluble in ether, benzene, hydrocarbons; relative density (water = 1):1.07, sodium borohydride is often used as a reducing agent in inorganic synthesis and organic synthesis. Sodium borohydride has strong selective reducibility and can selectively reduce carbonyl groups to hydroxyl groups, but it does not react with carbon-carbon double bonds and triple bonds. A small amount of sodium borohydride can reduce nitriles to aldehydes, and excess amounts can be reduced to amines. |
discovery process | sodium borohydride was discovered by H. C. Brown and his boss Schlesinger at the university of Chicago in 1942. The purpose at that time was to study the properties of borane and carbon monoxide complexes, but the reducing ability of borane to organic carbonyl compounds was discovered. Since borane was a rare substance at that time, it did not attract the attention of organic chemists. The development of borane chemistry benefited from the Second World War. At that time, the US Department of Defense needed to find a volatile uranium compound with the smallest molecular weight as possible for the enrichment of fissile material uranium 235. Uranium borohydride U(BH4)4 meets this requirement. The synthesis of this compound requires the use of lithium hydride, but the supply of lithium hydride is very small, so cheap sodium hydride is used as a raw material, and sodium borohydride is found in this process. Later, because the problem of the treatment process of uranium hexafluoride was solved, the Ministry of Defense abandoned the plan to enrich uranium 235 through uranium borohydride, and Brown's research topic became how to easily prepare sodium borohydride. Army Signal Corps is interested in the use of this new compound to prepare large amounts of hydrogen in the field. With their funding, related industrial research was carried out, and a process for the later industrial production of sodium borohydride was produced: 4NaH B(OCH3)3 → NaBH4 3NaOCH3 products are two solids. Recrystallization with an ether solvent to obtain pure sodium borohydride. |
use | hydrogen of sodium borohydride shows -1 valence here, so it has strong reducibility and can reduce inorganic substances with certain oxidizing properties. it is mainly used for reducing-COOH in organic synthesis to-CH20H, which plays a great role in organic synthesis, so it is called "universal reducing agent". It is a good reducing agent, which is characterized by stable performance and selectivity in reduction. It can be used as a reducing agent for aldehydes, ketones and acid chlorides, a foaming agent for plastics, a hydrogenation agent for the manufacture of dihydrostreptomycin, an intermediate for the manufacture of potassium borohydride, a raw material for the synthesis of boranes, and a treatment agent for the paper industry and mercury-containing sewage. Sodium borohydride provides organic chemists with a very convenient and mild means of reducing aldehydes and ketones. Prior to this, metal/alcohol methods were usually used to reduce carbonyl compounds, and sodium borohydride can achieve the reduction of aldehyde and ketone carbonyl groups under very mild conditions to produce primary alcohols and secondary alcohols. The reduction step is to dissolve the substrate in a solvent, usually methanol or ethanol, then cool it with an ice bath, add sodium borohydride powder to the mixture and stir until the reaction is complete. The reaction process can be monitored by thin layer chromatography. If the solvent is not alcohol, you need to add methanol or ethanol to react together. Sodium borohydride is a medium-strength reducing agent, so it shows good chemical selectivity in the reaction, only reducing the active aldehyde and ketone carbonyl group, and does not interact with esters and amides. is a good reducing agent, which is characterized by stable performance and selectivity in reduction. It can be used as a reducing agent for aldehydes, ketones and acid chlorides, a foaming agent for plastics, a hydrogenating agent for the manufacture of dihydrostreptomycin, an intermediate for the manufacture of potassium borohydride, a raw material for the synthesis of borane, and a treatment agent for the paper industry and mercury-containing sewage. Commonly used reducing agent. Used as a reducing agent for aldehydes, ketones, and acyl chlorides, a foaming agent for plastics, a hydrogenating agent for the manufacture of dihydrostreptomycin, an intermediate for the manufacture of potassium borohydride, and a raw material for the synthesis of borane, Paper industry mercury-containing sewage treatment agent, paper bleaching agent. It is used to make other borohydride salts, reducing agents, wood pulp bleaching, and plastic foaming agents The hydrogen of sodium borohydride shows -1 valence here, so it has strong reducibility and can reduce inorganic substances with certain oxidizing properties. It is mainly used for the reduction of-COOH in organic synthesis to-CH20H, which plays a great role in organic synthesis, so it is called "universal reducing agent". It is a good reducing agent, which is characterized by stable performance and selectivity in reduction. It can be used as a reducing agent for aldehydes, ketones and acid chlorides, a foaming agent for plastics, a hydrogenation agent for the manufacture of dihydrostreptomycin, an intermediate for the manufacture of potassium borohydride, a raw material for the synthesis of boranes, and a treatment agent for the paper industry and mercury-containing sewage. Sodium borohydride is a good reducing agent, which is characterized by stable performance and selectivity in reduction. It can be used as a reducing agent for aldehydes, ketones and acyl chlorides, a foaming agent for plastics, a hydrogenation agent for the manufacture of dihydrostreptomycin, an intermediate for the preparation of potassium borohydride, a raw material for the synthesis of borane, and a treatment agent for mercury-containing sewage in the paper industry. It is used as a raw material for the manufacture of diborane and other high-energy fuels, and is also used in the pharmaceutical industry. Used as a reducing agent for aldehydes, ketones, and acyl chlorides, a foaming agent for the plastic industry, a paper bleaching agent, and a hydrogenating agent for the pharmaceutical industry to manufacture dihydrostreptomycin |
Compared with sodium cyanoborohydride | Both are reducing agents. Sodium cyanoborohydride is more moderate than sodium borohydride and has better selectivity. Sodium borohydride can achieve the reduction of aldehyde and ketone carbonyl groups under very mild conditions to produce primary and secondary alcohols. The reduction step is to dissolve the substrate in a solvent, usually methanol or ethanol, then cool it with an ice bath, add sodium borohydride powder to the mixture and stir until the reaction is complete. Sodium borohydride is a medium-strength reducing agent, so it shows good chemical selectivity in the reaction. It only reduces the active aldehyde and ketone carbonyl group, and does not interact with esters and amides, and generally does not interact with carbon-carbon double bonds, Three bonds react. A small amount of sodium borohydride can reduce nitriles to aldehydes, and excess amounts can be reduced to amines. Sodium cyanoborohydride is a mild reducing agent. It is often used to selectively reduce imines made of aldehydes/ketones to amines. It is especially suitable for reductive amination reactions (Borch reaction). It reacts slowly with water. It can be used as a solvent for the reaction of sodium cyanoborohydride. Nucleophilic reducing agents such as lithium aluminum hydride and sodium borohydride cannot reduce the indole ring system. It is easy to reduce the heterocyclic ring under acidic conditions. In the past, excessive metal-acid combination was used, but now metal hydrides that are relatively stable to acidity, such as sodium cyanoborohydride, can make the reaction conditions milder. This reduction reaction is completed by attacking the hydride of β-protonated indole-3H indole cation. |
reducing ability | sodium borohydride is a relatively mild reducing agent, which has better reducing effect on aldehydes and ketones. Commonly used solvents are alcohol, tetrahydrofuran, DMF, water, etc. He generally does not reduce ester groups, carboxyl groups, and amides, but at high concentrations, high temperatures, combined with suitable dissolution or catalyzed by Lewis acids, weaker carbonyl groups such as ester groups can be reduced. To reduce aldehydes, ketones are not only mild, but also very effective. Basic operation: using methanol or ethanol as solvent, the mass of aldehyde ketone carbonyl compound and sodium borohydride 1:1 is sufficient. The temperature can be heated in stages, such as starting at 50 degrees. When the reaction is sufficient for 1 hour, the reaction can be refluxed and the progress can be monitored in a thin layer. The reaction is generally thorough. Generally speaking, the amount of solvent as long as it can meet the reaction will not form white paste. The reaction is not allowed to be strictly anhydrous; there are even examples of using water as a solvent: for example, reducing p-formyl benzoic acid, reducing formyl (formaldehyde), first neutralizing the carboxyl group with sodium hydroxide, and then reacting in water The formyl group can be successfully reduced. Sodium borohydride will quickly decompose and release hydrogen under acidic conditions, so it cannot react under acidic conditions, but it can be used under alkaline conditions. Sodium borohydride contacts carboxylic acid to quickly decompose and release hydrogen. Therefore, it cannot reduce the carboxylic acid alone. It must be used in combination with iodine. It first reacts with the carboxylic acid until the bubble stops, then adds iodine and continues to release the gas. Then add the borate ester formed by the decomposition of hydrochloric acid to obtain alcohol. Note: The reaction must be carried out in anhydrous THF. THF must be refluxed with sodium until benzophenone turns blue before it can be used! Otherwise, milk is formed during the reaction of carboxylic acid and sodium borohydride, not a clear liquid. Zinc borohydride was prepared by reacting sodium borohydride with anhydrous zinc chloride (dehydrated and dried above 200 degrees) in anhydrous THF for 3 hours. The solution mixture does not need to be separated and purified, and can be used as zinc borohydride to reduce carboxylic acids or esters at the reflux temperature of THF. The yield is good, but the double bonds may be somewhat affected, such as reducing cinnamic acid. There will be a part of the product of double bond reduction. |
toxicity | after contact with sodium borohydride, there are sore throat, cough, shortness of breath, headache, abdominal pain, diarrhea, dizziness, conjunctival congestion, pain and other symptoms. Dust should be prevented from flying, ventilation should be strengthened or protective masks should be worn, eyes should be protected, closed protective glasses should be worn, and food, water and smoking should not be allowed at work. After poisoning, he quickly left the scene, rested in a semi-lying position, inhaled fresh air, washed his eyes with a lot of water, removed contaminated clothes, and washed his whole body; those who entered the digestive tract immediately gargle, drink a lot of water to induce vomiting, and then send them to the hospital for treatment. When leaking, wear a filter protective mask to carefully clean the leakage. |
production method | sodium hydride methyl borate method adds boric acid and appropriate amount of methanol to a rectification kettle, slowly heats, and refluxes at 54 ℃ for 2 hours, then collects the azeotropic liquid of methyl borate and methanol. The azeotropic liquid is treated with sulfuric acid and rectified to obtain a purer product. The sodium hydride obtained by the interaction of hydrogen and sodium is sent to the condensation reaction tank, heated to about 220 ℃ under stirring, and the addition of methyl borate is started, and the heating is stopped at 260 ℃; the feeding temperature is controlled at 280 ℃ Below, continue to stir after feeding to make it fully react. After the reaction is completed, it is cooled to below 100 ℃ and centrifuged to obtain the condensation product filter cake. Add appropriate amount of water to the hydrolyser, slowly add the filter cake to the hydrolyser, control the temperature below 50 ℃, raise the temperature to 80 ℃ after the feeding is completed, centrifuge separation, and the hydrolysate is sent to the stratification device to rest for 1h and then automatically stratify, and the lower hydrolysate is sodium borohydride solution. Its H3BO3 3CH3OH → B(OCH3)3 3H2O2Na H2 → 2NaH4NaH B(OCH3)3 → NaBH4 3CH3ONa |
category | articles burning in contact with water |
toxicity classification | highly toxic |
acute toxicity | oral-rat LD50: 162 mg/kg; Oral-mouse LD50: 50 mg/kg |
explosive hazard characteristics | explosive in case of acid, water and oxidant |
flammability hazard characteristics | hydrogen gas is combustible when exposed to water, humid air and oxidant |
storage and transportation characteristics | warehouse ventilation and low temperature drying; Store separately from oxidant, halogen and strong acid; Moisture proof |
fire extinguishing agent | dry powder, dry sand |
spontaneous combustion temperature | 220°C |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |