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常用溶剂的纯化事项介绍

来源:郑州天顺食品添加剂有限公司 发布时间:2022-11-01 22:02:14 关注: 0 次
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1. 烷烃
1. Alkanes
如己烷、戊烷等。首先用浓硫酸洗涤几次以除去烯烃,水洗,CaCl2干燥,必要时用钠丝或P2O5干燥,蒸馏。存放于带塞的试剂瓶中。
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. 芳香烃类
2. Aromatic hydrocarbons
如苯、甲苯、二甲苯等。CaCl2干燥,必要时用钠丝或P2O5干燥, 蒸馏。存放于带塞的试剂瓶中。
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. 氯代烷烃类
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。绝对不能用钠丝干燥,否则会发生爆炸。长期储藏应放于密闭的瓶中,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. 醚类及呋喃类
4. Ethers and furans
如乙醚、四氢呋喃等。许多醚类在和空气接触下会慢慢生成 不易挥发且结构不明的过氧化物。过氧化物在加热下容易分解而爆炸。因此贮藏过久的醚类和呋喃类化合物在使用前,尤其是在蒸馏前应当检验是否有过氧化物的存在。检验的方法:用包含一滴淀粉指示剂的1 mL 10% KI 溶液和10 mL 醚液混合,没有颜色变化, 则没有过氧化物。或者用1%硫酸亚铁铵溶液,硫酸亚铁和硫氰化钾 溶液测试。若有,则加入5% FeSO4 或偏亚硫酸氢钠溶液于醚中 并摇动,使过氧化物分解。CaCl2预干燥,在钠丝或LiAlH4中回流 蒸出。储藏于密闭的瓶中,并保存于阴凉黑暗中。
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.
常用有机溶剂的纯化-乙醚 沸点34.51℃,折光率1.3526,相对密度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过氧化物。
氢氧化钾
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.
过氧化物的检验和除去:在干净和试管中放入2~3滴浓硫酸,1mL2%碘化钾溶液(若碘化钾溶液已被空气氧化,可用稀亚硫酸钠溶液滴到黄色消失)和1~2滴淀粉溶液,混合均匀后加入乙醚,出现蓝色即表示有过氧化物存在。除去过氧化物可用新配制的硫酸亚铁稀溶液(配制方法是FeSO47H2O60g,100mL水和6mL浓硫酸)。将100mL乙醚和10mL新配制的硫酸亚铁溶液放在分液漏斗中洗数次,至无过氧化物为止。
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.
醇和水的检验和除去:乙醚中放入少许高锰酸钾粉末和一粒氢氧化钠。放置后,氢氧化钠表面附有棕色颗粒,即证明有醇存在。水的存在用无水硫酸铜检验。先用无水氯化钙除去大部分水,再经金属钠干燥。其方法是:将100mL乙醚放在干燥锥形瓶中,加入20~25g无水氯化钙,瓶口用软木塞塞紧,放置一天以上,并间断摇动,然后蒸馏,收集33~37℃的馏分。用压钠机将1g金属钠直接压成钠丝放于盛乙醚的瓶中,用带有氯化钙干燥管的软木塞塞住。或在木塞中插一末端拉成毛细管的玻璃管,这样,既可防止潮气浸入,又可使产生的气体逸出。放置至无气泡发生即可使用;放置后,若钠丝表面已变黄变粗时,须再蒸一次,然后再压入钠丝。
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.
常用有机溶剂的纯化-四氢呋喃 (THF)沸点67℃(64.5℃),折光率1.4050,相对密度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.
四氢呋喃与水能混溶,并常含有少量水分及过氧化物。如要制得无水四氢呋喃,可用氢化铝锂在隔绝潮气下回流(通常1000mL约需2~4g氢化铝锂)除去其中的水和过氧化物,然后蒸馏,收集66℃的馏分(蒸馏时不要蒸干,将剩余少量残液即倒出)。精制后的液体加入钠丝并应在氮气氛中保存。
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.
处理四氢呋喃时,应先用小量进行试验,在确定其中只有少量水和过氧化物,作用不致过于激烈时,方可进行纯化。!!!!!四氢呋喃中的过氧化物可用酸化的碘化钾溶液来检验。如过氧化物较多,应另行处理为宜。可现用CuCl回流,除去大量的过氧化物。
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.
常用有机溶剂的纯化——二氧六环 沸点101.5℃,熔点12℃,折光率1.4424,相对密度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.
二氧六环能与水任意混合,常含有少量二乙醇缩醛与水,久贮的二氧六环可能含有过氧化物(鉴定和除去参阅乙醚)。二氧六环的纯化方法,在500mL二氧六环中加入8mL浓盐酸和50mL水的溶液,回流6~10h,在回流过程中,慢慢通入氮气以除去生成的乙醛。冷却后,加入固体氢氧化钾,直到不能再溶解为止,分去水层,再用固体氢氧化钾干燥24h。然后过滤,在金属钠存在下加热回流8~12h,最后在金属钠存在下蒸馏,压入饥丝密封保存。精制过的1,4-二氧环己烷应当避免与空气接触。
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. 酰胺类
5. Amides
如二甲基甲酰胺,二甲基乙酰胺,HMPT等。加入CaH2回流, 减压蒸出,否则其容易分解。加入新活化的分子筛储藏于瓶中,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.
常用有机溶剂的纯化,N,N-二甲基甲酰胺 -DMF N,N-二甲基甲酰胺 沸点149~156℃,折光率1.430 5,相对密度0.948 7。无色液体,与多数有机溶剂和水可任意混合,对有机和无机化合物的溶解性能较好。
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。常压蒸馏时有些分解,产生二甲胺和一氧化碳。在有酸或碱存在时,分解加快。所以加入固体氢氧化钾(钠)在室温放置数小时后,即有部分分解。因此,最常用硫酸钙、硫酸镁、氧化钡、硅胶或分子筛干燥,然后减压蒸馏,收集76℃/4800Pa(36mmHg)的馏分。其中如含水较多时,可加入其1/10体积的苯,在常压及80℃以下蒸去水和苯,然后再用无水硫酸镁或氧化钡干燥,最后进行减压蒸馏。纯化后的N,N-二甲基甲酰胺要避光贮存。
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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