Organic chemistry
Phenol | Structure, Preparation, Reactions, Properties | Crack Chemistry
Phenol – General View
Phenol is simplest Aromatic Alcohol with Moleculer formula of C₆H₅OH.
This Molecule consists of Phenyl Group (-C₆H₅) attached with the hydroxy group (-OH).
It is Acidic in Nature,it requires additional carefull handlings due to its acidic nature.
Phenol – Structure
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| Structure of Phenol |
Molecular Formula : C₆H₅OH
In Phenol,all ring carbon atoms are sp² hybridised and the Oxygen atom of the -OH group is sp³ hybridised
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| Hybridisation of Phenol |
• All Ring Carbon Atoms also have a p orbital and there are perpendicular to the plane of the Sigma Bond of the Ring.
• The Lateral Overlap of these p orbital produces a delocalised π molecular orbital
• There are Two Lone Pair of Electrons are Present in Oxygen Atom in the -OH group
Phenol – Resonance
According to the resonance theory, Phenol is considered to be a hybrid of the following resonance structures.
You can Notice that the Ortho & Para position in the resonance structure has a negative charge.
So Phenol undergoes Electrophilic Substitution reactions (E⁺)
Due to the presence of the -OH group, It undergoes Electrophilic Substitution faster than Benzene.
Because The Hydroxyl group donates the pair electrons to the ring resonance.
Phenol – Preparation
Phenol can be prepared by
From Chlorobenzene (Dow Process)
This involves the hydrolysis of the chlorobenzene with aqueous NaOH at high temperature and pressure followed by treatment with dilute HCl
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| Dow’s Process |
It was first introduced by Dow Chemical Company In U.S.A
Mechanism of Reaction
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| Mechanism of Dow’s Process |
Phenol – Electrophilic Substitution reactions
Electrophilic Substitution reactions Listed in this Posts are
• Halogenation Of Phenol
• Nitration Of Phenol
• Sulfonation Of Phenol
• Formylation Of Phenol (Reimer-Tiemann Reaction)
Halogenation Of Phenol :
Phenol reacts with bromine water (aqueous bromine) to give a precipitate of 2,4,6-tribromophenol.
This Reaction is also used in the laboratory to predict the Saturation/unsaturation Test of Organic Compounds.
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| Bromination of Phenol |
Nitration Of Phenol :
• When phenol reacts with Dilute Nitric Acid.
It gives a mixture of o- and p-nitrophenol.
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| Nitration Of Phenol |
• When phenol reacts with Excess of Concentrated Nitric Acid. It gives Picric Acid
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| Nitration Of Phenol – Excess |
Sulfonation Of Phenol :
When Phenol is treated with concentrated sulfuric acid at 20°C.It forms o-phenol sulfonic acid as a product
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| Sulfonation Of Phenol |
Reimer-Tiemann Reaction – Phenol
• This involves the treatment of Phenol with Chloroform in aqueous Sodium Hydroxide solution followed by acid-hydrolysis.
• It forms Salicyaldehyde as a product.
• Carbene Formed as an Intermediate
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| Formylation of Phenol |
To View Complete Reaction Mechanisms of Reimer Tiemann Reaction – Click Here
Kolbe Reaction – Phenol
This involves the treatment of sodium Phenoxide with carbon dioxide at 125°C under 6 atmospheres of pressure followed by acid-hydrolysis. It forms Salicylic acid at the end of the Reaction.
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| Kolbe Reaction |
Phenol – Properties
• Phenol is a Colorless, hygroscopic, crystalline solid
• Melting Point of Phenol – 42°C
• Boiling Point of Phenol – 182°C
• Phenol has a distinctive odor.
• Phenol is readily soluble in Ethanol and Organic solvents
• Below 65.8°C Phenol is Only Partially miscible with water but above this temperature, it is miscible in all proportions
Workout Test – Phenol
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