Here’s a explanation of the difference between nucleophilic and electrophilic aromatic substitution:
Nucleophilic Aromatic Substitution (NAS)
- A nucleophile (electron-rich species) attacks the aromatic ring.
- Works best if the ring has electron-withdrawing groups (like –NO₂).
- A halogen or leaving group is replaced.
- Often needs strong nucleophiles and high temperature.
- Example: Chlorobenzene + NaOH → Phenol
Electrophilic Aromatic Substitution (EAS)
- An electrophile (electron-poor species) attacks the aromatic ring.
- Works best if the ring has electron-donating groups (like –OH or –CH₃).
- A hydrogen atom is replaced.
- Usually happens under mild conditions with a catalyst.
- Example: Benzene + Br₂/FeBr₃ → Bromobenzene
Simple Rule:
- NAS → Nucleophile replaces a leaving group on an electron-poor ring.
- EAS → Electrophile replaces hydrogen on an electron-rich ring.