For many purposes, careful fractional distn gives adequate purification. disulfide can be removed by shaking vigorously for several hours with saturated KOH, separating, and washing with water: this treatment is repeated. The (CAS NO. ) is shaken with conc H₂SO₄ until there is no further coloration, then washed with water, dried with CaCl₂ or MgSO₄ 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 CCl₄ through activated alumina, and distn from KMnO₄. Carbonyl containing impurities can be removed by percolation through a Celite column impregnated with 2,4-dinitrophenylhydrazine (DNPH), H₃PO₄ and water. (Prepared by dissolving 0.5g DNPH in 6mL of 85% H₃PO₄ by grinding together, then mixing with 4mL of distd water and log Celite.)

Photochlorination of Carbon tetrachloride 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 Na₂SO₃, 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 CCl₄ with aq NaOH, then repeatedly with water and N₂ gas bubbled through the liquid for several hours. After drying over CaCl₂ it is percolated through silica gel and distd under dry N₂ before use.

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.