NAMED REACTION :

Acylation reaction, Kolbe's reaction, Reimer Tiemann's reaction

Acylation

The phenyl esters on treatment with anhydrous AlCl₃ in the presence of CS₂ as solvent,undergo FRIES REARRANGMENT in which the acyl group migrates from the phenolic oxygen atom to o- and p- position  of the benzene ring to give ortho and para ketones.

Kolbe's reaction

 this involves the interaction of sodium phenoxide with cabon dioxide at 400k under the pressure of 4-7 atmospheres followed by acid hydrolysis,salyicylic acid is formed.

Reimer Tiemann's reaction

On treating phenol with chloroform and sodium hydroxide at 340 K, followed by acid hydrolysis yields salicyladehyde (O – hydroxybenzaldehyde) (salicylaldehyde) and a very small amount of para-hydroxybenzaldehyde  is also formed .however, when carbon tetra chloride  is used, salicylic acidis formed.

Mechanism

The electrophile,dichloro methylene :ccl₂ is generated from chloro form by the action of the base

Riemer –tiemann reaction involves electrophilic substitution  on highly reactive phenoxide ring.