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Preparation of phenol from benzene derivatives Phenol was first isolated in the early nineteenth century from coal tar. Nowadays, phenol is commercially produced synthetically. In the laboratory, phenols may be prepared from benzene derivatives by any of the following methods. 1. From sodium benzene sulphonate Benezene sulphonic acid when treated with NaOH gives its sodium salt. Sodium benzene sulphonate. This when fused with NaOH at temperature between 570-620 K, gives sodium phenoxide, which on hydrolysis with dilute mineral acid gives phenol. 2. From Benzene diazonium chloride Benzene diazonium chloride is formed by treating aniline with nitrous acid (NANO2 + HCl) at 273-283 K temperature. On warming an aqueous solution of benzene diazonium chloride, it is hydrolysed to form phenol. 3. From Chlorobenzene (Dow’s process) Chlorobenzene on heating with 10% aqueous solution of NaOH at about 623K under 200 atmospheric pressure in the presence of copper salt catalyst, sodium phenoxide is ...

Preparation of Phenol From Coal Tar Phenol is commercially prepared from the middle oil fraction (443-503K) of coal tar distillate in which it occurs with cresols and naphthalene . First naphthalene is removed by chilling the fraction. The remaining oil is now treated with H 2 SO 4 to remove basic impurities and phenol is then extracted with dilute caustic soda . The aqueous layer is separated and phenol is precipitated with H 2 SO 4 or CO 2 . It is finally purified by distillation. Preparation of Phenol From Cumene Nowadays, phenol is manufactured from the hydrocarbon cumene. Cumene (isopropyl benzene) is first prepared from benzene and propene by Friedel-Crafts reaction in presence of phosphoric acid of aluminum oxide. Cumene is oxidized in presence of air to cumene hydroperoxide, which is then converted to phenol and acetone by treating it with dilute acid. Acetone, a byproduct of this reaction, is also obtained in large quantity by this method. Phenol has a melting point of 3...

When sodium salt of phenol ( sodium phenoxide ) is heated at about 400 K with carbon dioxide gas under a pressure of about 4-7 atmospheres and the product acidified, ortho hydroxy benzoic acid ( salicylic acid ) is formed as the main product. Saliccylic acid on actylation using acetic anhydride gives aspirin ( acetyl salicylic acid ). For more reaction of phenol visit Fries rearrangement: Reaction of phenol Coupling Reaction of Phenol Reimer-Tiemann reaction of phenol

Phenol reacts with dilute nitric acid at low temperature (298 k) to yield a mixture of ortho nitro phenl (15 %) and para nitrophenol (30-40 %). The ortho and para isomers of nitrophenol can be separated by steam distilation. O-Nitrophenol is steam volatile due to intra molecular hydrogen bonding while p-nitrophenol is less volatile due to intermolecular hydrogen bonding which causes the association of molecules. But, when nitration is carried out using concentrated nitric acid, phenol is converted to 2,4,6-trinitrophenol known as picric acid . In this reaction nitration is accompanied by oxidation of phenol. Preparation of Picric acid Industrially, picric acid is prepared by treating phenol, first with concentrated H 2 SO 4 which converts it to phenol-2,4-disulphuric acid. This yields picric acid on treating it with conc. HNO 3

Esters of phenols yield phenolic ketones on treatment with anhydrous aluminum chloride . This intermolecular rearrangement is called Fries rearrangement . This reaction involves the migration of an acyl group from phenolic oxygen to ortho and para positions of the aromatic ring with respect to the hydroxyl group. For example, phenyl ethanoate yields ortho- and para- hydroxy aceto phenones. Fries rearrangement is considered better than direct acylation as the yield is good. For more reaction of phenol visit Kolbe's Reaction of Phenol Coupling Reaction of Phenol Reimer-Tiemann reaction of phenol

When an ice cold solution of phenol is treated with an ice cold solution of benzene diazonium chloride in mildly alkaline medium p_hydroxy azo benzene (Azo dye) is formed. This reaction is called coupling reaction. For more reaction of phenol visit Kolbe's Reaction of Phenol Fries rearrangement: Reaction of phenol Reimer-Tiemann reaction of phenol

When phenol is heated with chloroform in presence of aqueous alkali ( NaOH ) at 340 K followed by hydrolysis of the resulting product a -CHO group is introduced at ortho position of benzene ring to form a phenolic aldehyde known as salicylaldehyde (O- hydroxy benzaldehyde) as the main product. A small amount of the para isomer is also obtained. This reaction is known as Reimer - Tiemann reaction. Instead of chloroform, if carbon tetrachloride is used in the above reaction salicylic acid (O- hydroxy benzoic acid) is obtained as the major product.

Reaction of Phenol with neutral Ferric Chloride Phenol reacts with neutral ferric chloride to give a violet coloured water soluble complex. C 6 H 5 OH + FeCl 3 --------------> [Fe(OC 6 H 5 ) 6 ] 3- + 3H + + 3HCl The complex formed is a coordination compound in which iron is hexacovalent. In fact, all compounds, whether aliphatic or aromatic containing the enol group (C=C-OH) but unlike alcohol give characteristics colours with neutral FeCl 3 . Different phenols give different colour. This reaction forms the basis of group test for the enolic grouping and may also be used to disitnguish between different phenols on the basis of the colour obtained.

Alcohols and phenols consist of two parts, an alkyl/aryl group and a hydroxyl group. The properties of alcohols and phenols are due to the OH group.The alkyl and aryl groups modify these properties. The boiling points of alcohols and phenols increase with increase in the number of carbon atoms. This is due to increase in van der Waals forces. In alcohols, the boiling points decrease with increase in branching. The reason is that when branching increases, vander Waals forces decreases due to decrease in surface area. The –OH group in alcohols and phenols contain a hydrogen bonded to an electronegative oxygen atom. Therefore, it is capable of forming hydrogen bond. Alcohols and phenols have higher boiling points than the corresponding other classes of compounds namely hydrocarbons, ether and halo alkanes/haloarenes of comparable molecular masses due to the presence of intermolecular hydrogen bonding in them. The solubility of alcohols and phenols in water is due to their ability to ...

ESTERIFICATION Alcohols and phenols react with carboxylic acids, acid chlorides and acid anhydrides to form esters. R-O-H + R' - COOH -----H+-----> ROCOR' + H 2 O Ethanol Acetic acid Ethyl acetate(Ester) C 2 -OH + CH 3 -COOH -----H 2 SO 4 ----------> C 2 H 5 O COCH 3 + H 2 O Ar-OH + R'-COOH ------------------> ArOCOR' + H 2 O Phenol Ester Ar-OH/ R-OH + (R'CO) 2 ---------H + ----------> Ar/ ROCOR' + R'COOH Anhydride Ease of esterification of alcohol is in the order primary> secondary> tertiary . The reaction with carboxylic acid and acid anhydride is carried out in presence of small amount of concentrated sulphuric acid. The reaction with carboxylic acid is reversible, and therefore, water is removed as soon as it is formed. The Reaction With Acid Chloride Is Carried Out In Presence Of A Base (Pyridine) so as to remove HCl. It also shifts the equilibrium to right hand side. The introduction of acetyl (CH3CO-) ...

Phenols react with aqueous sodium hydroxide to form sodium phenoxides. But alcohols are neutral to this reaction. The above reactions show that alcohols and phenols are acidic in nature. In fact, alcohols and phenols are Bronsted acids, that is they can donate a proton to a strong base (B:) On treating an alkoxide with water the starting alcohol is obtained. This reaction shows that water is a better proton donor than alcohol. In other words, alcohols are weaker acids than water. Also, in the above reaction, we can see that alkoxide ion is a better proton acceptor than hydroxide ion, which shows that alkoxides are stronger bases. For example, sodium ethoxide is a stronger base than sodium hydroxide. The acidic character of alcohols is due to the polar O-H bond. An electron releasing group increases the electron density over the oxygen atom tending to decrease the polarity of O-H bond. This decreases the acid strength of alcohols decreases in the following order. Obvio...

Alcohols and phenols react with highly electropositive alkali metals such as sodium, potassium etc to yield corresponding alkoxides/phenoxides and hydrogen. 2 R - OH + 2 Na ---------> 2 RONa (Sodium alkoxide) + H 2 2 C 2 H 5 OH + 2 Na ----------> 2 C 2 H 5 ONa (Sodium ethoxide)+ H 2 Related post Chemical properties of Alcohols and Phenols