英文名 | Acetic acid (glacial) |
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中文名 | 冰醋酸 |
类型 | 脂肪族化合物 |
CAS号 | 64-19-7 |
物理性质 | M 60.1, m 16.6℃, b 118℃, d4201.049, nD25 1.37171, n251.36995, pK25 4.76. |
提纯方法 | Usual impurities are traces of acetaldehyde and other oxidisable substances and water.(Glacial acetic acid is very hygroscopic. The presence of 0.1% water lowers its m by 0.2℃.) Purify it by adding some acetic anhydride to react with water present, heat it for 1hour to just below boiling in the presence of 2g CrO3 per 100 mL and then fractionally distil it [Orton & Bradfield J Chem Soc 960 1924, Orton & Bradfield J Chem Soc 983 1927]. Instead of CrO3, use 2-5% (w/w) of KMnO4, and boil under reflux for 2-6 hours.Traces of water have been removed by refluxing with tetraacetyl diborate (prepared by warming 1 part of boric acid with 5 parts (w/w) of acetic anhydride at 60℃, cooling, and filtering off, followed by distillation [Eichelberger & La Mer J Am Chem Soc 55 3633 1933]. Refluxing with acetic anhydride in the presence of 0.2g % of 2-naphthalenesulfonic acid as catalyst has also been used [Orton & Bradfield J Chem Soc 983 1927]. Other suitable drying agents include anhydrous CuSO4. |
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