Phenols undergo the same kind of substitution reactions that other aromatic compounds do. Formulate the reaction of p-methylphenol with Br₂ to give a mixture of two substitution products.

Verified step by step guidance

1. Step 1: Recognize that phenols are aromatic compounds with an -OH group attached to the benzene ring. The -OH group is an activating group, meaning it increases the reactivity of the benzene ring toward electrophilic substitution reactions.
2. Step 2: Identify the substituent already present on the benzene ring. In p-methylphenol, there is a methyl group (-CH3) in the para position relative to the hydroxyl group (-OH). Both groups are activating and direct substitution to the ortho and para positions.
3. Step 3: Introduce Br2 as the electrophile in the reaction. Bromine reacts with the benzene ring in the presence of the activating groups, leading to electrophilic aromatic substitution.
4. Step 4: Predict the positions where bromine will substitute. The -OH group directs substitution to the ortho and para positions relative to itself, while the -CH3 group also directs substitution to its ortho and para positions. This results in two major products: bromine substitution at the ortho position relative to the -OH group and bromine substitution at the ortho position relative to the -CH3 group.
5. Step 5: Write the chemical equations for the reaction. Use MathML to represent the structures of p-methylphenol and the two substitution products formed. Ensure the reaction mechanism shows the formation of the bromonium ion and its attack on the activated positions of the benzene ring.

Key Concepts

Aromatic Substitution Reactions

Aromatic substitution reactions involve the replacement of a hydrogen atom in an aromatic compound with another atom or group. This process preserves the aromaticity of the compound, which is a key characteristic of aromatic systems. In the case of phenols, these reactions typically occur at the ortho and para positions relative to the hydroxyl group, due to its electron-donating effects.

Electrophilic Aromatic Substitution (EAS)

Electrophilic Aromatic Substitution (EAS) is a specific type of aromatic substitution where an electrophile reacts with an aromatic compound. The presence of electron-donating groups, like the hydroxyl group in phenols, enhances the reactivity of the aromatic ring towards electrophiles, facilitating the substitution process. In the case of p-methylphenol reacting with Br2, the bromine acts as the electrophile.

Regioselectivity in Substitution Reactions

Regioselectivity refers to the preference of a chemical reaction to occur at one location over another in a molecule. In the context of p-methylphenol, the methyl group directs the incoming electrophile to the ortho and para positions relative to the hydroxyl group, leading to a mixture of substitution products. Understanding regioselectivity is crucial for predicting the outcomes of substitution reactions in aromatic compounds.