如何制备无水四氯化碳？ carbon tetrachloride [56-23-51 m 153.8, b 76.s0, d25 1.5842. for many purposes, careful fractional distn gives adequate purification. carbon disulfide can be removed by shaking vigorously for several hours with saturated koh, separating, and washing with water: this treatment is repeated. the ccl4 is shaken with conc h2so4 until there is no further coloration, then washed with water, dried with cac12 or mgs04 and distd (from p2o5 if desired). it must not be dried with sodium. an initial refluxing with mercury for 2h removes sulfides. other purification steps include passage of dry cc4 through activated alumina, and distn from kmn04. carbonyl containing impurities can be removed by percolation through a celite column impregnated with 2,4-dinitrophenylhydrazine (dnph), h3p04 and water. (prepared by dissolving 0.5g dnph in 6ml of 85% h3p04 by grinding together, then mixing with 4ml of distd water and log celite.) [schwartz and parks anal chem 33 1396 19611. hotochlorination of ccl4 has also been used: ccl4 to which a small amount of chlorine has been added is illuminated in a glass bottle (e.g. for 24h with a 200w tungsten lamp near it), and, after washing out the excess chlorine with 0.02m na2s03, the ccl4 is washed with distd water and distd from p2o5. it can be dried by passing through 4a molecular sieves and distd. another purification procedure is to wash cc14 with aq naoh, then repeatedly with water and n2 gas bubbled through the liquid for several hours. after drying over cac12 it is percolated through silica gel and distd under dry n2 before use [klassen and ross j phys chem 91 3664 19871. rapid purification: distil, discarding the first 10% of distillate or until the distillate is clear. the distilled ccl4 is then stored over 5a molecular sieves. ref: purification of laboratory chemicals 前段时间我回过一个帖子处理四氯化碳，他是用的koh+h2o+etoh萃取，在用cacl2除去乙醇， 我后来也没弄明白加乙醇的目的。 查看更多
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