Electrophilic Aromatic Substitution

Reaction type in nitration of methyl benzoate

Electrophilic aromatic substitution.

Electrophile in nitration

Nitronium ion (NO2+).

Role of sulfuric acid in nitration

Protonates nitric acid to generate NO2+.

Why add acid mixture slowly

Reaction is highly exothermic.

Why keep temperature below 15°C

To minimize side products.

Major nitration product of methyl benzoate

Meta-nitromethyl benzoate.

Why is methyl benzoate meta-directing

The ester group is electron withdrawing.

Directing effect

Controls where substitution occurs.

Activating effect

Controls reaction rate relative to benzene.

Meta-directing groups

NO2, CHO, COR, COOH, COOR, CONR2.

Ortho/para-directing activating groups

OH, OR, NR2, NHCOR.

Halogens directing effect

Ortho/para directing.

Halogens activating or deactivating

Deactivating.

Electron-withdrawing groups

Decrease ring electron density and direct meta.

Electron-donating groups

Increase ring electron density and direct ortho/para.

Nitronium ion formula

NO2+.