Electrophilic Aromatic Substitution

Flashcards focused on key terms and concepts related to electrophilic aromatic substitution, including definitions and mechanisms for various reactions.

Electrophilic Aromatic Substitution

A reaction where a hydrogen atom in benzene is replaced by an electrophile, preserving the aromaticity of the ring.

Resonance-Stabilized Carbocation

An intermediate formed during electrophilic aromatic substitution characterized by delocalized positive charge across multiple resonance structures.

Halogenation

A type of electrophilic aromatic substitution where a hydrogen atom is replaced by a halogen (Cl or Br) using a Lewis acid catalyst.

Nitration

Electrophilic aromatic substitution that introduces a nitro group (NO₂) onto the benzene ring, commonly using HNO₃ and H₂SO₄.

Sulfonation

A reaction where a hydrogen atom in benzene is replaced by a sulfonyl group (SO₃H) in electrophilic aromatic substitution.

Friedel-Crafts Alkylation

A reaction involving the addition of an alkyl group to a benzene ring using an alkyl halide and a Lewis acid.

Friedel-Crafts Acylation

Substitution reaction that introduces an acyl group (RCO) to the benzene ring using an acid chloride and a Lewis acid.

Directing Effects

The influence of substituents on the position of further electrophilic substitution on an aromatic ring, indicating whether it favors ortho, meta, or para positions.

Ortho/Para Directors

Substituents that activate the benzene ring and direct electrophilic substitution primarily to the ortho and para positions.

Meta Directors

Substituents that deactivate the benzene ring and direct substitution primarily to the meta position.

Inductive Effect

The effect of electronegative atoms that can withdraw electron density away from the benzene ring, impacting the reactivity in electrophilic substitution.

Resonance Effect

The stabilization of a molecule through the delocalization of electrons, affecting the direction and rate of electrophilic aromatic substitution.

Diazotization

A chemical reaction forming a diazonium salt by treating a primary amine with nitrous acid.

Azo Coupling

Formation of azo compounds by reacting diazonium salts with strongly electron-donating aromatic compounds.

Nucleophilic Aromatic Substitution

A substitution reaction where a nucleophile replaces a leaving group on a benzene ring, commonly involving an electron-withdrawing group.

Benzylic Bromination

A radical reaction that selectively substitutes bromine at the benzylic position of alkyl benzenes due to the stability of the benzylic radical.

Reduction of Nitro Compounds

The process of converting nitro groups (NO₂) into amino groups (NH₂) through various reduction methods.