问题：甲苯干燥问题
类型：求助 (悬赏分:3分)
提问：tengfei168
等级：▲▲
版块：有机化学问题(jimuwei,fpcwin1211,netpanda,yjgzfl,Ftian,)
信誉：96%
回复：13
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时间：2009-10-27 12:12:36 编辑加入/取消收藏订制/取消短消息举报该贴

甲苯用分子筛干燥除水，需要马氏炉高温干燥分子筛后才能使用。现在我们没有这个条件，请问各位还有其他能除微量的材料吗？谢谢！

回复人：aguo551,▲▲▲▲ (学习交流进步) 时间：2009-10-27 12:32:12 编辑	1楼
无水氯化钙

回复人：mengniu,★★★★★ () 时间：2009-10-27 13:12:23 编辑	2楼
硫酸钙

回复人：xiaoyaolcl,★★★★★ (由于爱好,所以从事) 时间：2009-10-27 13:46:26 编辑	3楼
试试氢化钙吧

回复人：hxt263,▲ (终生学习) 时间：2009-10-27 14:02:25 编辑	4楼
干燥分子筛不用太高温度，真空150度就可以了。还是分子筛为甲苯除水比较好！

回复人：绿林好汉,▲ () 时间：2009-10-28 08:36:10 编辑	5楼
金属钠，

回复人：rqs1,★★★★ (技术提升为己任) 时间：2009-11-01 16:05:29 编辑	6楼
同意金属钠处理，但是没有8楼说的那样，让瓶子殉葬。

回复人：东方未明,▲▲▲ (青山之花不再怒放) 时间：2009-11-01 11:45:11 编辑	7楼
CaH回流蒸馏呀

回复人：seaword,▲▲▲▲ (人生合成，合成人生) 时间：2009-11-01 14:32:38 编辑

8楼

Toluene [108-88-31 M 92.1, b 110.6O, dl0 0.87615, d25 0.86231, n1.49693, n25 1.49413.Dried with CaC12, CaH2 or CaS04, and dried further by standing with sodium, P2O5 or CaH2. It can be fractionally distd from sodium or P2O5. Unless specially purified, toluene is likely to be contaminated with methylthiophenes and other sulfur containing impurities. These can be removed by shaking with conc H2SO4, but the temperature must be kept below 30° if sulfonation of toluene is to be avoided. A typical procedure consists of shaking toluene twice with cold conc H2SO4 (100mL of acid per L), once with water, once with aqueous 5% NaHC03 or NaOH, again with H20, then drying successively with Cas04 and P2O5, with final distn from P2O5 or over LiAlH4 after refluxing for 30min. Alternatively, the reatment with NaHC03 can be replaced by boiling under reflux with 1% sodium amalgam. Sulfur compounds can also be removed by prolonged shaking of the toluene with mercury, or by two distns from AlCl3, the distillate then being washed with water, dried with K2CO3 and stored with sodium wire. Other purification procedures include refluxing and distn of sodium dried toluene from diphenylpicrylhydrazyl, and from SnC12 (to ensure freedom from peroxides).
It has also been co-distd with 10% by volume of ethyl methyl ketone, and again fractionally distd. [Brown and Pearsall J Am Chem Soc 74 191 1952.1 For removal of carbonyl impurities see *benzene. Toluene has been purified by distn under nitrogen in the presence of sodium benzophenone ketyl. Toluene has also been dried with MgS04, after the sulfur impurities have been removed, and then fractionally distd from P2O5 and stored in the dark [Tabushi et al. J Am Chem Soc 107 4465 19851. Toluene can be purified by passage through a tightly packed column of Fuller's earth.
Rapid purification: Alumina, CaH2 and 4A molecular sieves (3% w/v) may be used to dry toluene (6h stirring and standing). Then the toluene is distd, discarding the first 5% of distillate, and is stored over molecular sieves (3A, 4A) or Na wire.

回复人：shennt,▲▲ (从事有机合成工作) 时间：2009-11-01 15:37:13 编辑	9楼
金属钠,加点二苯甲酮做指示剂,不过要注意安全,最后的钠处理是个问题,最好就连瓶子一起埋葬.

回复人：liyinping,▲ (热爱化工的新人！！) 时间：2009-11-01 17:34:32 编辑	10楼
还是用分子筛除水比较好，先问一下你确定甲苯中有水吗？

回复人：ct1228 ,▲▲ (因为喜欢，所以爱上它，因为爱上它，所以进入它玄妙的世界) 时间：2009-11-02 09:27:16 编辑	11楼
一般有机物干燥脱水，最好是用分子筛吧。实在没有条件的话，可以考虑用钠处理，注意点安全。

回复人：云龙1962,▲▲▲ () 时间：2009-11-02 09:57:53 编辑	12楼
金属钠,加点二苯甲酮做指示剂,不过要注意安全.

回复人：tengfei168,▲▲ () 时间：2009-11-02 11:39:00 编辑	13楼
已经打分了！

得分人：mengniu :1, 绿林好汉 :1, ct1228 :1,

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