Page 163 - Pharm.Org.Chem-I 02-06-05-101
P. 163
Sulphonation occurs in conc. Or fuming H2SO4
SO3H
+ H2SO4 + H2O
Mechanism:
2 H2SO4 SO3 + H3O+ +HSO4 -
Sulfur trioxide (E+)
Benzene sulfonic acid
Sulphonation reaction is reversible
it proceeds with strong conc. acid and desulfonation can be accomplished using hot dilute aqueous
acid (dilute sulfuric acid).
23
4) Friedel-Crafts Alkylation
An aromatic ring can be alkylated by an alkyl halide in presence of lewis acid which
serves to generate a carbocation electrophile.
For example reaction of benzene and isopropyl chloride in presence of aluminium
chloride.
E.g.
24
161
