Partial hydrogenation of phenol will give cyclohexanone, a precursor to nylon. Condensation of alkylphenols, phenol, or diphenols with formaldehyde will give phenolic resins, a well-known example of which is Bakelite. Condensation with acetone develops bisphenol-A, a key precursor to epoxide resins and polycarbonates. The main uses of phenol, consuming two-thirds of its making, include its transformation to precursors for plastics.
Finally, sodium phenoxide on acidification makes phenols. When chlorobenzene is reacted with sodium hydroxide at 623K and 320 atm sodium phenoxide is formed. Some of the approaches of preparation of phenols are explained below:Ĭhlorobenzene is an example of haloarenes which is made by mono replacement of the benzene ring. In laboratories, phenol is mainly created from benzene derivatives. Nowadays, with developments in technologies, some new methods have come up for the making of phenols in laboratories. They are weak acids and mostly form phenoxide ions by dropping one positive hydrogen ion (H+) from the hydroxyl group., phenol was mainly manufactured from coal tar. Preparation of phenols from diazonium salts, benzene sulphonic acid, haloarenes, cumene. When phenol reacts with iron(III) chloride solution, a powerful violet-purple solution is produced. In the presence of boron trifluoride (BF 3 ) phenol is reacted with diazomethane and as a result anisole is obtained as the main product and nitrogen gas as a byproduct.Ĭ 6 H 5 OH + CH 2 N 2 → C 6 H 5 OCH 3 + N 2
Phenol is transformed to benzene when it is distilled with zinc dust, or when phenol vapor is passed over grains of zinc at 400☌: This is a case of the Schotten-Baumann reaction:Ĭ 6 H 5 OH + C 6 H 5 COCl → C 6 H 5 OCOC 6 H 5 + HCl When a mixture of phenol and benzoyl chloride is shaken in the occurrence of dilute sodium hydroxide solution, phenyl benzoate is produced. It is easily neutralized by sodium hydroxide giving sodium phenate but is weaker than carbonic acid, it cannot be neutralized by sodium bicarbonate or sodium carbonate to release carbon dioxide. The aqueous mixture of phenol is weakly acidic and changes blue litmus somewhat to red. It reacts with dilute nitric acid at room temperature to produce a mixture of 2-nitrophenol and 4-nitrophenol while with concentrated nitric acid, many nitro groups get replaced on the ring to produce 2, 4, 6-trinitrophenol which is also known as picric acid. However, phenol's ring is so powerfully activated-second only to aniline-that chlorination or bromination of phenol will lead to replacement on all carbon atoms para and ortho to the hydroxy group, not only on one carbon. By this overall approach, several groups can be attached to the ring, through halogenation, sulfonation, acylation, and other methods. Phenol is extremely reactive to electrophilic aromatic substitution as the oxygen atom's pi electrons give electron density into the ring.
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