1. Learning Objectives 1.Properties of phenols 2.Reaction of phenols

2. Preparation of phenol From aryl sulphonic acids Aryl sulphonic acid gives corresponding phenol on heating with molten sodium hydroxide at 570-620 K.

3. Preparation of phenol Chlorobenzene is hydrolysed by treating it with NaOH at 623 K and 320 atm.

4. Preparation of phenol From hydrolysis of diazonium salt Diazonium salts are prepared by treating an aromatic primary amine with nitrous acid (NaNO 2 + HCl) at low temperature.

5. Preparation methods Synthesis from cumene By decarboxylation of salicylic acid with soda lime

6. Acidity of phenol Phenol is more acidic than aliphatic alcohols because conjugate base is stabilized by resonance.

7. Reactions of phenol Electrophilic aromatic substitution —OH group is ortho, para- directing group and activates the benzene rings.

8. Chemical reaction of phenol Fries rearrangement Distillation with Zn dust :

9. Nitration With dilute HNO 3, it gives ortho and para-isomers which can be separated easily by distillation. With concentrated HNO 3 phenol is converted to 2,4,6-trinitrophenol.

10. Bromination of phenol

11. Kolbe’s reaction

12. Reimer-Tiemann Reaction Mechanism

13. Reimer Tiemann Reaction The mechanism involves dichlorocarbene as an intermediate On treating phenol with chloroform in presence of sodium hydroxide, a —CHO group is introduced at ortho position of benzene ring.

14. Fries rearrangement Esters of phenols yield phenolic ketones on treatment with anhydrous aluminium chloride.

15. Coupling Reaction p-hydroxy azo benzene

16. Phenol Reactions: A Summary