问题：提纯乙酰丙酮
类型：求助 (悬赏分:3分)
提问：jingxiawu
等级：▲
版块：有机化学问题(jimuwei,fpcwin1211,netpanda,yjgzfl,Ftian,)
信誉：50%
回复：1
阅读：835
时间：2006-06-13 08:25:47 编辑加入/取消收藏订制/取消短消息举报该贴

我现在有一实验怀疑是乙酰丙酮出问题了,请教各位高手知道怎么提纯?谢谢!

回复人：pccs,★ (知之为知之, 不知Google之...) 时间：2006-06-13 09:20:13 编辑

1楼

Acetylacetone (2,4-pentanedione) [123-54-6] M 100.1, b 45°/30mm, d30-2 0.9630, n18-5
1.45178, pKi -5.0 (enol), -6.6 (keto), pK2 8.95 Small amounts of acetic acid were removed by
shaking with small portions of 2M NaOH until the aqueous phase remained faintly alkaline. The sample, after
washing with water, was dried with anhydrous Na2SO^ and distd through a modified Vigreux column [Cartledge
/ Am Chem Soc 73 4416 7957]. An additional purification step is fractional crystn from the liquid.
Alternatively, there is less loss of acetylacetone if it is dissolved in four volumes of *benzene and the soln is
shaken three times with an equal volume of distd water (to extract acetic acid): the *benzene is then removed by
distn at 43-53° and 20-30mm through a helices-packed column. It is then refluxed over ?2O5 (lOg/L) and
fractionally distd under reduced pressure. The distillate (sp conductivity 4 x 10~8 ohm" 1Cm'1) was suitable for
polarography [Fujinaga and Lee Talanta 24 395 7977]. To recover used acetylacetone, metal ions were stripped
from the soln at pH 1 (using 10OmL O. IM H2SO4/L of acetylacetone). The acetylacetone was washed with
(1:10) ammonia soln (lOOmL/L) and with distd water (lOOmL/L, twice), then treated as above. It complexes
with Al, Be, Ca, Cd, Ce , Cu, Fe2+, Fe3+, Mn, Mg, Ni, Pb and Zn.

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