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yy19

至尊木虫 (小有名气)

要求不高的话,加足量无水硫酸钠即可。
11楼2006-09-26 10:59:10
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xiaohe160

金虫 (正式写手)

可以用分子筛来除水
12楼2006-09-26 13:38:36
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中流砥柱

木虫 (小有名气)

用分子筛即可。
13楼2006-09-28 11:01:54
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samuel01

金虫 (正式写手)

1,2-Dichloroethane [107-06-2] M 99.0, b 83.4°, d 1.256, n15 1.44759. Usually prepared bychlorinating ethylene, so that likely impurities include higher chloro derivatives and other chloro compoundsdepending on the impurities originally present in the ethylene. It forms azeotropes with water, MeOH, EtOH,trichloroethylene, CC14 and isopropanol. Its azeotrope with water (containing 8.9% water, and b 77°) can be used to remove gross amounts of water prior to final drying. As a preliminary purification step, it can be steam distd, and the lower layer was treated as below.
Shaken with cone H2SO4 (to remove alcohol added as an oxidation inhibitor), washed with water, then dilute KOH or aqueous Na2CO3 and again with water. After an initial drying with CaCl2, MgSO4 or by distn, it is
refluxed with P2^^ CaSO4 or CaH2 and fractionally distd. Carbonyl-containing impurities can be removed as described for chloroform.

以上是试剂纯化手册,Purification of Laboratory Chemicals, Elsevier图书,第5版,这个 书上方法我以为最可信。
泛舟东海 跃马昆仑
14楼2007-01-21 23:15:34
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