The steam of (CAS NO. ) was passed through a boiling soln containing lmole of phenol and 1.5-2.0moles of NaOH in 5L of H₂O until all non-acidic material had distd. The residue was cooled, acidified with 20% (vh) H₂SO₄, and the phenol was separated, dried with CaSO₄ and fractionally distd under reduced pressure. It was then fractionally crystd several times from its melt. Purification via the benzoate has been used by Berliner, Berliner and Nelidow. The benzoate was crystd from 95% EtOH, then hydrolysed to the free phenol by refluxing with two equivalents of KOH in aq EtOH until the soln became homogeneous. It was acidified with HCl and extracted with diethyl ether. The ether layer was freed from benzoic acid by thorough extraction with aqueous NaHCO₃, and, after drying and removing the ether, the phenol was distd.

Phenol has also been crystd from a 75% w/w soln in water by cooling to 11 °C and seeding with a crystal of the hydrate. The crystals were centrifuged off, rinsed with cold water (0-2 °C) satd with phenol, and dried. It can be crystd from pet ether.

Draper and Pollard added 12% water, 0.1% aluminium (can also use zinc), and 0.05% NaHCO₃ to phenol, and distd at atmospheric pressure until the azeotrope was removed, The phenol was then distd at 25mm. Phenol has also been dried by distn from the benzene soln to remove the water-benzene azeotrope and the excess benzene, followed by distn of the phenol at reduced pressure under nitrogen. Processes such as this are probably adequate for analytical grade phenol which has as its main impurity water. Phenol has also been crystd from pet ether/benzene or pet ether (b 40-60°C). Purified material is stored in a vacuum desiccator over P₂O₅ or CaSO₄.