What are the products of each aromatic substitution reaction? b.

Key Concepts

Aromatic Substitution Reactions

Aromatic substitution reactions involve the replacement of a hydrogen atom in an aromatic compound, such as benzene, with another substituent. These reactions typically preserve the aromaticity of the compound, which is crucial for the stability of the aromatic system. Common types include electrophilic aromatic substitution (EAS), where an electrophile attacks the aromatic ring.

Electrophilic Aromatic Substitution (EAS)

Electrophilic aromatic substitution is a specific type of aromatic substitution where an electrophile reacts with the aromatic ring. In this process, the aromatic system temporarily loses its aromaticity as the electrophile forms a sigma complex, which is then deprotonated to restore aromaticity. The reaction often requires a catalyst, such as AlBr3, to facilitate the formation of the electrophile.

Role of Catalysts in EAS

Catalysts, like AlBr3 in this reaction, are substances that increase the rate of a chemical reaction without being consumed. In EAS, AlBr3 helps generate a more reactive electrophile from CH3Br, allowing it to effectively attack the benzene ring. The presence of a catalyst is essential for overcoming the activation energy barrier associated with the reaction.