问题：傅克酰基化反应的问题
类型：求助 (悬赏分:3分)
提问：qqqqa
等级：▲
版块：有机化学问题(jimuwei,fpcwin1211,netpanda,yjgzfl,Ftian,)
信誉：56%
回复：8
阅读：1079
时间：2009-03-17 17:19:16 编辑加入/取消收藏订制/取消短消息举报该贴

我用噻吩和乙酰氯反应，氯化氢气体呼呼的往外冒，但是就是得不到产品，求帮助一下。我个人认为后处理可能有问题。我先蒸出溶剂，然后加入甲苯萃取，水洗，水洗的时候，三氯化铝或者氯化锌的水溶液跟有几层不是分的很好，加大量的水，水层也有颜色，水少的时候水溶液就很浑浊，不知道怎么办才好

回复人：hzl82612,★ (相信我，没错的！) 时间：2009-03-17 17:29:30 编辑	1楼
三氯化铝作催化剂，可先水解，再水洗、脱溶，可能效果会好点

回复人：claymore,★★★★★ (C-H活化，kumada,suzuki,stille,negishi.cross-coupling.) 时间：2009-03-17 18:27:49 编辑	2楼
http://www.orgsyn.org/orgsyn/pdfs/CV2P0008.pdf

回复人：chemwu70,★ (共同进步) 时间：2009-03-17 20:32:36 编辑	3楼
1楼说的对,应先冰解再水洗、脱溶，

回复人：claymore,★★★★★ (C-H活化，kumada,suzuki,stille,negishi.cross-coupling.) 时间：2009-03-17 18:26:44 编辑	4楼
这个亲电反应很困难吗?跟着Organic Synthesis 走,连脑子都可以不用动...

回复人：claymore,★★★★★ (C-H活化，kumada,suzuki,stille,negishi.cross-coupling.) 时间：2009-03-17 18:27:16 编辑

5楼

1. Procedure
In a 500-cc. round-bottomed, three-necked flask provided with a thermometer, dropping funnel, a
liquid-sealed stirrer, and calcium chloride tube are placed 16.8 g. (0.2 mole) of thiophene (p. 578), 15.6
g. (14 cc., 0.2 mole) of acetyl chloride, and 200 cc. of dry benzene. The solution is cooled to 0°, and 52
g. (23 cc., 0.2 mole) of freshly distilled stannic chloride is added dropwise, with efficient stirring, during
the course of about forty minutes. The reaction mixture assumes a purple color when the first drops of
stannic chloride are added, and soon a purple solid precipitates.
After all the stannic chloride has been added, the cooling bath is removed and the mixture stirred for
one hour longer. The addition product is hydrolyzed by the slow addition of a mixture of 90 cc. of water
and 10 cc. of concentrated hydrochloric acid. The yellow benzene layer is separated, washed with 25 cc.
of water, and dried over 5–10 g. of anhydrous calcium chloride. Benzene and unchanged thiophene
(Note 1) are distilled through a short fractionating column (using an oil bath), and the residual liquid is
distilled under reduced pressure. The yield of 2-acetothienone, b.p. 89–91°/9 mm., is 20–21 g. (79–83
per cent of the theoretical amount) (Note 2).
2. Notes
1. By shaking the recovered benzene-thiophene mixture with a solution of 5.5 g. of mercuric chloride,
10 g. of sodium acetate, and 10 cc. of alcohol in 80 cc. of water, the unchanged thiophene is converted
to the 2-chloromercurithiophene (containing a small amount of the dimercurichloride); from this the free
thiophene can be obtained by treatment with hydrochloric acid. The recovered thiophene amounts to 2–
2.5 g.
2. 2-Acetothienone has the following physical constants: d20 1.168, n20 1.566. Its semicarbazone melts
at 186–187° (corr.).
3. Discussion
2-Acetothienone has been prepared by treating thiophene with acetyl chloride in the presence of
aluminum chloride1 or stannic chloride,2 and by treating 2-chloromercurithiophene with acetyl chloride.3
The present method is essentially that of Stadnikoff and Goldfarb.2 Stannic chloride is superior to
aluminum chloride as a catalyst for this reaction as aluminum chloride induces polymerization of the
thiophene.

回复人：jams,▲ (有机化学就是一旦有机会就要在变化中不停的学习) 时间：2009-03-25 00:37:56 编辑	6楼
后处理的时候,将反应液缓慢放入碎冰中，并不停搅拌，萃取时可以调节PH至弱酸性，那样水层就不会有太多的产物在内

回复人：claymore,★★★★★ (C-H活化，kumada,suzuki,stille,negishi.cross-coupling.) 时间：2009-03-25 06:48:39 编辑	7楼
已经打分了！

得分人：hzl82612 :1, chemwu70 :1, jams :3,

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