加金属钠和少量  二苯甲酮,煮沸直到溶液变为 深蓝色,蒸馏即可!一般需要3天时间,要有耐性哦!

如果THF重水的含量较大时，先用氢氧化钾干燥一周，后用 钠砂回流干燥，直至二苯甲酮变蓝色或紫色为止，我们就是这样做的，效果很好。



沸点67℃(64.5℃)，折光率1.405 0，相对密度0.889 2。

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。

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。

有几种方法可用：
1）Na，二苯甲酮法
THF中加入钠沙，二苯甲酮，回流，直至变蓝为止，蒸馏出THF，封存，即可，一般不要超过1周；

2）CaH2法
最简单方便，干燥效果最好：THF加入CaH2，回流3小时，直接蒸馏出来，封存

Tetrahydrofuran  [109-99-91  M 72.1, b 25O/176mm,  66°/760mm,  diO 0.889,  ny 1.4070,  pK -2.48 (aq H2SOq).  It is obtained  commercially  by  catalytic hydrogenation  of  furan  from  pentosan- containing agricultural residues.  It was purified by refluxing with, and distilling from LiAIH4 which removes water, peroxides, inhibitors and other impurities [Jaeger et al. JAm Chem Soc 101 717 19791.  Peroxides can also be removed by passage through a column of activated alumina, or by treatment with aq ferrous sulfate and sodium bisulfate, followed by solid KOH.  In both cases, the solvent is then dried and fractionally distd from sodium.  Lithium wire or vigorously stirred molten potassium have also been used for this purpose. CaH2 has also been used as a drying agent. Several methods are available for obtaining the solvent almost anhydrous.  Ware [J Am Chem Soc 83 1296 19611 dried vigorously with sodium-potassium alloy until a characteristic blue colour was evident in the solvent at Dry-ice/cellosolve temperatures. The solvent was kept in contact with the alloy until distd for use. Worsfold and Bywater [J Chem Soc  5234 19601, after refluxing and distilling from P2O5 and KOH, in turn, refluxed the solvent with sodium-potassium alloy and fluorenone until the green colour of the disodium salt of fluorenone was well established.  [Alternatively, instead of fluorenone, benzophenone, which forms a blue ketyl, can be used.]  The tetrahydrofuran  was then fractionally distd, degassed and stored above CaH2. p-Cresol  or hydroquinone inhibit peroxide formation. The method described by Coetzee and Chang [Pure Appl Chem 57
633 198.51 for 1,4-dioxane also applies here.  Distns should always be done in the presence of a reducing agent, e.g.  FeS04. It  irritates  the  skin, eyes  and  mucous membranes and  the  vapour  should  never be  inhaled.  It  is  HIGHLY  FLAMMABLE and  the  necessary precautions should  be  taken.

Rapid purification:  Purification as for diethyl ether，

四氢呋喃先用氯化钙干燥，然后加入钠丝或钠砂回流，加入少许二苯甲酮做指示剂，回流直到变蓝，蒸出。整个过程最好氮气保护。

引用回帖:

Originally posted by johnso at 2009-2-7 13:08:
加金属钠和少量  二苯甲酮,煮沸直到溶液变为 深蓝色,蒸馏即可!一般需要3天时间,要有耐性哦!

三天！时间太长了吧！
我用钠－二苯甲酮干燥THF只要过夜就可以了！
方法是：THF预干燥，氮气保护下加钠屑回流过夜（如果达到了干燥效果，钠屑会变成松散的钠球），加入一小片二苯甲酮即可变色（先是蓝色后会变成暗紫色）。