|n-Butyllithium Chemical Properties|
|n-Butyllithium Usage And Synthesis|
|Outline||N-Butyllithium is colorless or slightly yellow transparent liquid and is stable at room temperature with the lithium hydride being eliminated by heating. It can be decomposed upon water and is soluble in hydrocarbons and ethers. It can also form complex with ethers, amines and sulfides. Using n-hexane as the solvent, its density is 0.675 g/ml. It is generally can be prepared into dilute solution with molar concentration of 1.0 M-1.3 M range and the mass percentage concentration being between 9% -13%. It can be widely used as drug intermediates, liquid crystal monomer and for the organic catalytic reactions in rubber industry. |
With n-Butyllithium (BuLi) as the initiator, tetrahydrofuran (THF) as a structure modulating agent, tin tetrachloride (SnCl4) as a coupling agent for synthesis of integrated rubber SIBR, the integral rubber SIBR is a kind of novel rubber used for tread with its distinguishing feature being that the molecular chain segment constituting a variety of structures with segments of different structures providing different performance of the rubber. For example, flexible segment can enable the rubber to have excellent low temperature performance while reducing the rolling friction and improving the wear resistance of the tire; while the rigid segment can increase the wet grip power of the rubber to improve the safety property of the tire in the wet road, making SIBR become by far the most comprehensive performance of the diene rubber. Owing to the excellent overall performance of SIBR, it is considered to be a kind of hot rubber of this century with good development prospects.
The preparation of the Ethyl ether solution
Under the protection of anhydrous and oxygen-free nitrogen, add 200 ml of anhydrous ether and 8.6 grams (1.25 mol) lithium wires which are cut into pieces into a 500 mL dried three-necked flask equipped with a stirrer, low temperature thermometer, windpipe, drying tube and a dropping funnel, add drop-wise of 30 droplet of solution containing 68.5 g (0.5 M) n-bromobutane and 100 mL of anhydrous ether. Cool it at a dry ice-acetone bath to -10 ℃ until seeing the solution become cloudy and the lithium wire exhibits a metallic luster bright spots which indicates the initiation of the reaction. The remaining n-bromobutane solution was added over within 30 minutes. It is further subject to slow warming to 0-10 ℃, and stirring for 1-2 hours. Under the protection of nitrogen gas, it is put through a glass tube plugged with glass wool for filtration. Transfer the ether solution of n-butyllithium to previously pre-washed nitrogen storage container, with the yield of 80-90%.
The preparation of the N-hexane solution
Under the protection of nitrogen gas, add 120 mL of n-hexane solution, 4.8 g (0.7 mol) of lithium wire to a three-necked flask equipped with a dropping funnel, a thermometer, and a condenser, add drop wise of 29.6 g (0.32 mmol) of n-butyl chloride, slowly increase the temperature and maintain steady boiling and the addition can be completed within about 1 hour, continue for refluxing of 1.5 hours, cool and stand overnight, filter under nitrogen and the filtrate was put into nitrogen gas for preservation.
|Preparation of butyllithium||Under the protection of argon atmosphere, add 3 L hexane (or petroleum ether at 60 to 90 °C) to a 5000 ml three-necked flask. Wash the 140g (20mol) lithium metal sheet with n-hexane (or petroleum ether 60-90 ℃) clean; wear disposable gloves, and quickly tear the metal lithium sheet into small pieces, and add to 5000 ml three-necked flask, fit with a mechanical stirrer, cool it using ice-salt bath to about 0 degrees (note the temperature should not too low, otherwise will lead to slower initiation); add drop wise of 925 g(10 mol) of chlorobutane, and keep the temperature at below 15 degrees (note that the color after the reaction initiation is purple gray; we should drop slowly at initial stage with the reaction being strongly exothermic; pay special attention not to punch materials), after the completion of the addition, the temperature of the ice-salt is kept below 15 degrees with stirring being continued for 2 hours, then the ice-salt bath was removed and stirred for 1 hour at room temperature and further changed to reflux device, and gradually warmed and refluxed for 4-5 hours, cool to room temperature, stand and settle overnight with the supernatant being Butyllithium solution which was compressed into the storage flask with argon gas; the residue was added with 2 L solvent for stirring, settle overnight, and the supernatant solution was merged into butyllithium for future usage.|
The residue treatment: put the above residue bottle into a pot fitted with sand and place it at safe place for exposure to air for 1-2 months (without spontaneous combustion) until the solid in the system becomes white. Immediately dump them out, add throw into water from far way in open ground. If the local climate is humid, during first few days, you should place a drying tube on both sides of the bottle. For haste usage of reaction flask, after the transfer of n-Butyllithium solution, we can slowly add drop wise of tert-butyl alcohol for treatment under an argon atmosphere and ice-salt bath cooling.
|Butyllithium titration methods and calibration||Butyllithium must be calibrated before use, double titration method is complicate and thus is generally not applied. Instead we can use single titration method. The specific methods are as follows: |
1) Titration reagents: 1mol / L of butanol/xylene solution (sec-butyl alcohol and xylene must use activated with 5A molecular sieves)
2) Indicator: 2, 2'-bipyridyl
3) Solvent: xylene (must use activated with 5A molecular sieves)
4) Methods of operation: Under the protection of argon, add a magneton, 20 mL of xylene, and a small amount of indicator into a 100 mL three-necked flask with tipping plug 100ml three-necked flask, then use 2 mL syringe with a precise 2 mL scale to take 2 ml butyllithium and immediately transfer it into the bottle (the air in the syringe requires to be replaced with argon gas, and the argon gas should be excluded during the extracting of butyllithium and the syringe be subject to pumping back and forth for several times in the butyllithium solution to avoid the negative effect of the traces of water and air in the syringe on the accuracy of titration), the reaction system becomes purple, then wash the same syringe (the reason for using the same syringe is to reduce the titration error) clean, dry, and washed with titrant for two to three times; accurately weigh the titration agent for titrate the system to yellow, this is the endpoint of the titration.
5) Repeat the titration once with the error of the two experiments being within 2% the results; then we can consider it as accurate.
6) Titration result: Titration dosage (ml)/2 is the molar concentration of butyllithium
1) In case of air, the n-Butyllithium is easily to have spontaneous combustion; when weigh it the tip of the needle will spark in the air.
2) The whole process must be used in an argon atmosphere, pay special attention to safety.
3) Upon the combustion of Butyllithium, you should extinguish fire with sand. Usually sand should be presented within reach in normal time.
4) During the preparation and usage of Butyllithium, it is best not to operate with a single person to avoid the situation in which unforeseen circumstances occur and can’t be handled by a single person.
The above information is edited by the Chemicalbook of Dai Xiongfeng.
|How to take it||Fill the syringe with nitrogen gas and put into the bottle containing n-butyllithium; take n-butyllithium and purge into the reaction system pre-filled with nitrogen gas (of course, the system includes a pressure-equalizing dropping funnel), and then rotate the plug and add drop wise of n-butyl based lithium. |
For small amount of usage, direct inhale it using a syringe and slowly add drop wise; you should of course ensure that the container is filled with nitrogen gas. Remember to prepare a flask containing a small amount of dry tetrahydrofuran or petroleum ether; further wash the used syringe.
|Chemical Properties||It is liquid at room temperature. But sometimes also exhibit as power form. Boiling point is 80-90 ℃ (0.013Pa), the relative density is 0.68-0.70. It is soluble in most organic solvent.
|Uses||It can be used as polymerization catalyst and hydrocarbon agent. |
It can be U\used as a chemical product intermediate and linker.
Butyllithium has a wide application in the field of organic synthesis and is used for elongating carbon chain and used as a basic laboratory product. 1, the metal reaction: R-H + n-Butyl-Li → R-Li + Butane, the generated alkyllithium substance can react with a variety of substances. 2, it can be used for direct metalation reaction: when aromatic compound with substitute group is reacted with n-Butyllithium, the metal lithium can be connected to the aromatic compound. 3, nucleophilic addition and substitution reactions 4, halogen - metal replacement.
N-Butyllithium solution is mainly used for the synthesis of the anionic polymerization initiator in the field of pharmaceutical intermediates and can also used in synthetic rubber, synthetic fragrances, liquid crystal materials and other industries and fields.
N-Butyllithium (n-C4H9Li) is mainly used as the catalyst of organic reactions and is widely applied to the organic catalysis in pharmaceutical intermediates, liquid crystal monomers, pesticides and rubber industry.
|Production method||Under nitrogen, cool the pure ether and lithium wire (cut into piece) to -10 ℃, start stirring, add drop wise of the ether solution of bromine butane. Upon completion, slowly warm to 0-10 ℃ and have reaction of 1-2 h, and filter to obtain a solution of n-Butyllithium in ether (trade) with a yield of being 80% -90%.
|Category||spontaneously combustible substance upon coming across water
|Explosives and hazardous properties||it is explosive when having polymerization with the styrene
|Flammability and hazard characteristics||when its concentration is greater than 20%, it can have spontaneous combustion in the air; it can also have spontaneous combustion upon contact with water, carbon dioxide; it is flammable when exposed to heat and fire.
|Storage characteristics||Treasury: ventilation low-temperature drying; it should be kept away from water and carbon dioxide
|Chemical Properties||clear yellow solution|
|Extinguishing agent||dry powder
|n-Butyllithium Preparation Products And Raw materials|
|Preparation Products||2-Cyanophenylboronic acid-->2-Bromopyridine-5-boronic acid-->1-BENZOTHIOPHENE-2-SULFONYL CHLORIDE-->4-Hydroxyphenylboronic acid-->5-Methoxypyridine-3-boronic acid-->2,3-Difluorophenylboronic acid-->5-Bromopyridine-3-boronic acid-->2-BROMOPYRIDIN-3-YLBORONIC ACID-->2-METHYL-2H-INDAZOLE-3-CARBOXYLIC ACID-->Ethyl 1-methyl-1H-pyrazole-5-carboxylate-->4-METHYLDIBENZOTHIOPHENE-->4-Methoxyphenylboronic acid ,98%-->4,5-DIBROMOTHIOPHENE-2-CARBOXALDEHYDE-->4-Carboxylphenylboronic acid pinacol ester-->2,5-Dichlorophenylboronic acid-->5-BROMOPYRIDINE-2-CARBONYL CHLORIDE-->4-N-BUTYLTOLUENE-->1-Naphthylboronic acid-->2,3,6-TRIFLUOROBENZOIC ACID-->5-Chloropyridine-2-boronic acid-->TRIS(PENTAFLUOROPHENYL)BORANE-->4-CHLORO-2-METHYLPHENYLBORONIC ACID-->3-ISOPROPYLPHENYLBORONIC ACID-->2-Bromo-5-iodopyridine-->2-Chloropyridine-5-boronic acid-->3,4,5-TRICHLOROTHIOPHENE-2-CARBONYL CHLORIDE-->5-Methyl-2-pyridineboronic acid-->3-BROMO-1-BENZOFURAN-->2,4-Dibromothiophene-->1-Methyl-1H-pyrazole-5-carboxylic acid-->2,3,4-Tribromothiophene-->2,4,6-Trifluorobenzoic acid-->METHYL 3-BROMOTHIOPHENE-2-CARBOXYLATE-->2,4,6-Trichlorobenzoic acid-->DIMETHYL(3-PHENOXY-2-OXOPROPYL)PHOSPHONATE-->Benzofuran-2-boronic acid-->ETHYL 5-CHLOROTHIOPHENE-2-CARBOXYLATE-->Isoquinoline-4-carbaldehyde-->Fenarimol-->1,3-Thiazole-2-carbaldehyde|