In the previous videos on Organic Chemistry, i have discussed about the 3 General Steps involved in Electrophilic Aromatic Substitution Reaction Mechanism and the Halogenation of Benzene. Do check them out if you have missed that. Today, we will look at how Nitration of Benzene proceeds via Electrophilic Substitution Mechanism.
3 Steps in Nitration of Benzene via Electrophilic Substitution Reaction Mechanism:
1: Production of the electrophile (the nitronium ion, NO2+ ion) using conc. H2SO4 and conc. HNO3
Conc. HNO3 acts as a base in the presence of the stronger acid, conc. H2SO4.
The nitronium ion, NO2+ formed is a stronger electrophile.
Equation is HNO3 (base) + 2H2SO4 (acid) → NO2+ (electrophile) + 2HSO4– + H3O+
2: Formation of the carbocation intermediate from the attack of the NO2+ on the benzene ring
This is the slow rate-determining step since it involves the formation of an unstable carbocation intermediate from a stable aromatic compound.