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常用溶劑的純化事項(xiàng)介紹

發(fā)布來源:http://www.laiyanglicheng.com    更新時(shí)間:2022-01-08 點(diǎn)擊數(shù):93

1. 烷烴

1. Alkanes
如己烷、戊烷等。用濃硫酸洗滌幾次以除去烯烴,水洗,CaCl2干燥,必要時(shí)用鈉絲或P2O5干燥,蒸餾。存放于帶塞的試劑瓶中。
Such as hexane, pentane, etc. First, wash several times with concentrated sulfuric acid to remove olefins, wash with water, dry CaCl2, dry with sodium wire or P2O5 if necessary, and distill. Store in reagent bottle with stopper.
2. 芳香烴類
2. Aromatic hydrocarbons
如苯、甲苯、二甲苯等。CaCl2干燥,必要時(shí)用鈉絲或P2O5干燥, 蒸餾。存放于帶塞的試劑瓶中。
Such as benzene, toluene, xylene, etc. CaCl2 is dried and, if necessary, dried with sodium wire or P2O5 and distilled. Store in reagent bottle with stopper.
3. 氯代烷烴類
3. Chloroalkanes
如二氯甲烷、氯仿、四氯化碳、二氯乙烷等。水洗除去醇等,CaCl2干燥,在P2O5,或CaH2中回流蒸出。不能用鈉絲干燥,否則會(huì)發(fā)生爆炸。長期儲(chǔ)藏應(yīng)放于密閉的瓶中,并保存于黑暗中。
Such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, etc. Wash with water to remove alcohol, etc., dry CaCl2, reflux and evaporate in P2O5 or CaH2. Never dry with sodium wire, otherwise it will explode. Long term storage should be placed in closed bottles and kept in the dark.
4. 醚類及呋喃類
4. Ethers and furans
如乙醚、四氫呋喃等。許多醚類在和空氣接觸下會(huì)慢慢生成 不易揮發(fā)且結(jié)構(gòu)不明的過氧化物。過氧化物在加熱下容易分解而爆炸。因此貯藏過久的醚類和呋喃類化合物在使用前,尤其是在蒸餾前應(yīng)當(dāng)檢驗(yàn)是否有過氧化物的存在。檢驗(yàn)的方法:用包含一滴淀粉指示劑的1 mL 10% KI 溶液和10 mL 醚液混合,沒有顏色變化, 則沒有過氧化物。或者用1%硫酸亞鐵銨溶液,硫酸亞鐵和硫氰化鉀 溶液測試。若有,則加入5% FeSO4 或偏亞硫酸氫鈉溶液于醚中 并搖動(dòng),使過氧化物分解。CaCl2預(yù)干燥,在鈉絲或LiAlH4中回流 蒸出。儲(chǔ)藏于密閉的瓶中,并保存于陰涼黑暗中。
Such as ether, tetrahydrofuran, etc. Many ethers will slowly form non-volatile peroxides with unknown structure in contact with air. Peroxide is easy to decompose and explode under heating. Therefore, ether and furan compounds stored for too long should be checked for the presence of peroxide before use, especially before distillation. Test method: Mix 1 ml of 10% ki solution containing a drop of starch indicator and 10 ml of ether solution. If there is no color change, there is no peroxide. Or test with 1% ammonium ferrous sulfate solution, ferrous sulfate and potassium thiocyanide solution. If so, add 5% FeSO4 or sodium metabisulfite solution into ether and shake to decompose the peroxide. CaCl2 is pre dried and refluxed in sodium filament or LiAlH4. Store in closed bottles and keep in a cool dark place.
常用有機(jī)溶劑的純化-乙醚 沸點(diǎn)34.51℃,折光率1.3526,相對密度0.71378。普通乙醚常含有2%乙醇和0.5%水。久藏的乙醚常含有少量過氧化物。
氫氧化鉀
Purification of common organic solvents- ether boiling point 34.51 ℃, refractive index 1.3526 and relative density 0.71378. Ordinary ether usually contains 2% ethanol and 0.5% water. Long stored ether often contains a small amount of peroxide.
過氧化物的檢驗(yàn)和除去:在干凈和試管中放入2~3滴濃硫酸,1mL2%碘化鉀溶液(若碘化鉀溶液已被空氣氧化,可用稀亞硫酸鈉溶液滴到黃色消失)和1~2滴淀粉溶液,混合均勻后加入乙醚,出現(xiàn)藍(lán)色即表示有過氧化物存在。除去過氧化物可用新配制的硫酸亞鐵稀溶液(配制方法是FeSO47H2O60g,100mL水和6mL濃硫酸)。將100mL乙醚和10mL新配制的硫酸亞鐵溶液放在分液漏斗中洗數(shù)次,無過氧化物為止。
Inspection and removal of peroxide: put 2 ~ 3 drops of concentrated sulfuric acid, 1mL2% potassium iodide solution (if the potassium iodide solution has been oxidized by air, dilute sodium sulfite solution can be used to drop to the yellow to disappear) and 1 ~ 2 drops of starch solution into the clean test tube. Mix evenly and add ether. The presence of blue indicates the presence of peroxide. The peroxide can be removed by using the newly prepared dilute ferrous sulfate solution (the preparation method is feso47h2o60g, 100ml water and 6ml concentrated sulfuric acid). Wash 100ml of ether and 10ml of newly prepared ferrous sulfate solution in the separating funnel for several times until there is no peroxide.
醇和水的檢驗(yàn)和除去:乙醚中放入少許高錳酸鉀粉末和一粒氫氧化鈉。放置后,氫氧化鈉表面附有棕色顆粒,即證明有醇存在。水的存在用無水硫酸銅檢驗(yàn)。先用無水氯化鈣除去大部分水,再經(jīng)金屬鈉干燥。其方法是:將100mL乙醚放在干燥錐形瓶中,加入20~25g無水氯化鈣,瓶口用軟木塞塞緊,放置以上,并間斷搖動(dòng),然后蒸餾,收集33~37℃的餾分。用壓鈉機(jī)將1g金屬鈉直接壓成鈉絲放于盛乙醚的瓶中,用帶有氯化鈣干燥管的軟木塞塞住?;蛟谀救胁逡荒┒死擅?xì)管的玻璃管,這樣,既可防止潮氣浸入,又可使產(chǎn)生的氣體逸出。放置無氣泡發(fā)生即可使用;放置后,若鈉絲表面已變黃變粗時(shí),須再蒸一次,然后再壓入鈉絲。
Inspection and removal of alcohol and water: put a little potassium permanganate powder and a grain of sodium hydroxide into ether. After placing, brown particles are attached to the surface of sodium hydroxide, which proves the existence of alcohol. The presence of water was tested with anhydrous copper sulfate. First remove most of the water with anhydrous calcium chloride, and then dry with metal sodium. The method is as follows: put 100ml ether into a drying conical flask, add 20 ~ 25g anhydrous calcium chloride, plug the bottle mouth with a cork, place it for more than one day, shake it intermittently, then distill and collect the fraction at 33 ~ 37 ℃. Use a sodium press to directly press 1g metal sodium into sodium wire, put it into a bottle containing ether, and plug it with a cork with a calcium chloride drying tube. Or insert a glass tube whose end is pulled into a capillary in the wooden plug, so as to prevent moisture from entering and make the generated gas escape. Place it until there is no bubble; After placing, if the surface of the sodium wire has turned yellow and thick, it must be steamed again, and then pressed into the sodium wire.
常用有機(jī)溶劑的純化-四氫呋喃 (THF)沸點(diǎn)67℃(64.5℃),折光率1.4050,相對密度0.8892。
Purification of common organic solvents tetrahydrofuran (THF) has a boiling point of 67 ℃ (64.5 ℃), a refractive index of 1.4050 and a relative density of 0.8892.
四氫呋喃與水能混溶,并常含有少量水分及過氧化物。如要制得無水四氫呋喃,可用氫化鋁鋰在隔絕潮氣下回流(通常1000mL約需2~4g氫化鋁鋰)除去其中的水和過氧化物,然后蒸餾,收集66℃的餾分(蒸餾時(shí)不要蒸干,將剩余少量殘液即倒出)。精制后的液體加入鈉絲并應(yīng)在氮?dú)夥罩斜4妗?/div>
Tetrahydrofuran is miscible with water and often contains a small amount of water and peroxide. If anhydrous tetrahydrofuran is to be prepared, lithium aluminum hydride can be refluxed in isolation of moisture (usually 1000ml requires about 2 ~ 4G lithium aluminum hydride) to remove the water and peroxide, and then distilled to collect the fraction at 66 ℃ (do not evaporate dry during distillation, pour out a small amount of residual liquid). The refined liquid shall be added to sodium wire and stored in nitrogen atmosphere.
處理四氫呋喃時(shí),應(yīng)先用小量進(jìn)行試驗(yàn),在確定其中只有少量水和過氧化物,作用不致過于激烈時(shí),方可進(jìn)行純化。?。。。?!四氫呋喃中的過氧化物可用酸化的碘化鉀溶液來檢驗(yàn)。如過氧化物較多,應(yīng)另行處理為宜??涩F(xiàn)用CuCl回流,除去大量的過氧化物。
When treating tetrahydrofuran, a small amount should be tested first, and the purification can be carried out only when it is determined that there is only a small amount of water and peroxide and the effect is not too intense.!!!!! The peroxide in tetrahydrofuran can be tested with acidified potassium iodide solution. If there are many peroxides, it should be treated separately. CuCl can be used for reflux to remove a large amount of peroxide.
常用有機(jī)溶劑的純化——二氧六環(huán) 沸點(diǎn)101.5℃,熔點(diǎn)12℃,折光率1.4424,相對密度1.0336。
Purification of common organic solvents - dioxane has a boiling point of 101.5 ℃, a melting point of 12 ℃, a refractive index of 1.4424 and a relative density of 1.0336.
二氧六環(huán)能與水任意混合,常含有少量二乙醇縮醛與水,久貯的二氧六環(huán)可能含有過氧化物(鑒定和除去參閱乙醚)。二氧六環(huán)的純化方法,在500mL二氧六環(huán)中加入8mL濃鹽酸和50mL水的溶液,回流6~10h,在回流過程中,慢慢通入氮?dú)庖猿ド傻囊胰@鋮s后,加入固體氫氧化鉀,直到不能再溶解為止,分去水層,再用固體氫氧化鉀干燥24h。然后過濾,在金屬鈉存在下加熱回流8~12h,在金屬鈉存在下蒸餾,壓入饑絲密封保存。精制過的1,4-二氧環(huán)己烷應(yīng)當(dāng)避免與空氣接觸。
Dioxane can be mixed with water at will. It often contains a small amount of diethanol acetal and water. Dioxane stored for a long time may contain peroxide (see ether for identification and removal). Purification method of dioxane: add 8ml concentrated hydrochloric acid and 50ml water solution into 500ml dioxane and reflux for 6 ~ 10h. In the reflux process, slowly inject nitrogen to remove the generated acetaldehyde. After cooling, add solid potassium hydroxide until it cannot be dissolved again, remove the water layer, and then dry it with solid potassium hydroxide for 24h. Then it is filtered, heated and refluxed in the presence of metal sodium for 8 ~ 12h, distilled in the presence of metal sodium, pressed into hungry silk and sealed for storage. Refined 1,4-dioxane should avoid contact with air.
5. 酰胺類
5. Amides
如二甲基甲酰胺,二甲基乙酰胺,HMPT等。加入CaH2回流,    減壓蒸出,否則其容易分解。加入新活化的分子篩儲(chǔ)藏于瓶中,并注明日期。
Such as dimethylformamide, dimethylacetamide, hmpt, etc. Add CaH2 to reflux and evaporate it under reduced pressure, otherwise it is easy to decompose. Add the newly activated molecular sieve and store it in a bottle with date.
常用有機(jī)溶劑的純化,N,N-二甲基甲酰胺 -DMF N,N-二甲基甲酰胺 沸點(diǎn)149~156℃,折光率1.430 5,相對密度0.948 7。無色液體,與多數(shù)有機(jī)溶劑和水可任意混合,對有機(jī)和無機(jī)化合物的溶解性能較好。
Purification of common organic solvents, N, N-dimethylformamide DMF, N, N-dimethylformamide, boiling point 149 ~ 156 ℃, refractive index 1.430 5, relative density 0.948 7. Colorless liquid, which can be freely mixed with most organic solvents and water. It has good solubility in organic and inorganic compounds.
N,N-二甲基甲酰胺含有少量水分。常壓蒸餾時(shí)有些分解,產(chǎn)生二甲胺和一氧化碳。在有酸或堿存在時(shí),分解加快。所以加入固體氫氧化鉀(鈉)在室溫放置數(shù)小時(shí)后,即有部分分解。因此,常用硫酸鈣、硫酸鎂、氧化鋇、硅膠或分子篩干燥,然后減壓蒸餾,收集76℃/4800Pa(36mmHg)的餾分。其中如含水較多時(shí),可加入其1/10體積的苯,在常壓及80℃以下蒸去水和苯,然后再用無水硫酸鎂或氧化鋇干燥,進(jìn)行減壓蒸餾。純化后的N,N-二甲基甲酰胺要避光貯存。
N. N-dimethylformamide contains a small amount of water. Some decompose during atmospheric distillation to produce dimethylamine and carbon monoxide. Decomposition is accelerated in the presence of acid or base. Therefore, after adding solid potassium hydroxide (sodium) and placing it at room temperature for several hours, it will be partially decomposed. Therefore, calcium sulfate, magnesium sulfate, barium oxide, silica gel or molecular sieve are most commonly used for drying, followed by vacuum distillation to collect the fraction of 76 ℃ / 4800pa (36mmhg). If there is much water, 1 / 10 volume of benzene can be added, the water and benzene can be evaporated under normal pressure and 80 ℃, then dried with anhydrous magnesium sulfate or barium oxide, and finally distilled under reduced pressure. The purified n, N-dimethylformamide should be stored away from light.

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