Physical Properties Of Phenol 5p4d2k

PHYSICAL PROPERTIES OF PHENOL Pure phenols are generally colourless solids or liquids. The light colour usually associated with phenols is due to its oxidation by air in presence of light

(b) When phenol is treated with bromine water, 2,4,6-tribromophenol is formed as white precipitate. Kolbe’s reaction :

Phenols, in general, are insoluble in water; but phenol itself, and polyhydric phenols are fairly soluble in water which is believed to be due to the formation of hydrogen bonds with water. (iii) Due to intermolecular hydrogen bonding, phenols usually have relatively high boiling points than the corresponding hydrocarbons, aryl halides and alcohols They possess characteristic colour. They are highly toxic in nature and possess antiseptic properties. They may produce wounds on skin.

CHEMICAL PROPERTIES OF PHENOL Nitration: (a) When phenol react with dilute nitric acid at low temperature (298 K), gives a mixture of ortho and para nitrophenols. (b) When phenol is react with concentrated nitric acid, gives 2,4,6-trinitrophenol. 2. Halogenation: (a) When the reaction is carried out in solvents of low polarity such as CHCl or CS and at low 3 2 temperature, monobromophenols are formed.

Reimer-Tiemann reaction : 0n treating phenol with chloroform in the presence of sodium hydroxide, a -CH0 group is introduced at ortho position of benzene ring. This reaction is known as Reimer - Tiemann reaction.The intermediate substituted benzal chloride is hydrolysed in the presence of alkali to produce salicylaldehyde. The mechanism ofthe Reimer-Tiemann reaction is believed to involve the formation of dichlormethylene. Na0H+CHCl :CCl +NaCl+H 0 3 2 2 Libermann’s Reaction : When phenol is treated with sodium dissolved in conc. Sulphuric acid, a red colouration appears, which changes to blue on adding aqueous Na0H. This reaction is called Libermann’s reaction 2NaN02 + H2S04 Na2S04 + 2HN02 Nitrous acid

5. Reaction of phenol with zinc dust : When phenol is heated with zinc dust gives benzene. 6. Oxidation:0xidation of phenol with chromic acid produces a conjugated diketone known as benzoquinone. In the presence of air, phenols are slowly oxidised to dark coloured mixtures containing quinones. Lab preparation

Reaction type : Oxidation Summary

 This industrial method is the primary source of phenol.

 Oxidation at the benzylic position gives the hydroperoxide which cleaves to give phenol and acetone.

 Cheap reagents and important products make the process attractive.

Phenol derivatives are also used in the preparation of cosmetics including sunscreens,[19] hair colorings, and skin lightening preparations.[20] sources

Notable sources of natural phenols in human nutrition include berries, tea, beer, olive oil, chocolate or cocoa, coffee, pomegranates, popcorn, yerba maté, fruits and fruit based drinks (including cider, wine and vinegar) and vegetables. Herbs and spices, nuts (waln uts, peanut) and algae are also potentially significant for supplying certain natural phenols. Natural phenols can also be found in fatty matrices like olive oil.[111] Cloudy olive oil has the higher levels of phenols, or polar phenols that form a complex phenol-protein complex. Phenolic compounds, when used in beverages, such as prune juice, have been shown to be helpful in the color and sensory components, such as alleviating bitterness.[112] Some advocates for organic farming claim that organically grown potatoes, oranges, and leafy vegetables have more phenolic

Uses: Its major uses involve its conversion to plastics or related materials. Phenol and its chemical derivatives are key for building polycarbonates, epoxies, Bakelite, nyl on, detergents, herbicides such as phenoxy herbicides, and numerouspharmaceutical drugs. Phenol is also used as an oral anesthetic/analgesic in products such as Chloraseptic or other brand name and generic equivalents, commonly used to temporarily treat pharyngitis.

compounds and these may provide antioxidantprotection against heart disease and cancer.[113] However evidence on substantial differences between organic food and conventional food is insufficient to make claims that organic food is safer or more healthy than conventional food.[114][115]