Question

Monobromination of toluene gives a mixture of three bromotoluene products. Draw and name them.

Short answer

Bromination of toluene is an electrophilic substitution reaction of toluene with bromine as an electrophile. The methyl group (polarizable, electron-donating group) in toluene can impart a positive inductive effect and hyperconjugation. Because of the positive inductive effect and hyperconjugation of the methyl group, the electron density on the aromatic ring increases. Methyl group act as an activating group.

Step-by-step solution

Electrophilic substitution reaction

Bromination of toluene is an electrophilic substitution reaction of toluene with bromine as an electrophile. The methyl group (polarizable, electron-donating group) in toluene can impart a positive inductive effect and hyperconjugation. Because of the positive inductive effect and hyperconjugation of the methyl group, the electron density on the aromatic ring increases. Methyl group act as an activating group.

Bromination of toluene

Toluene is brominated using bromine as the brominating reagent and ferric bromide$\left({\text{FeBr}}_3\right)$as the catalyst. Bromination is similar to the other electrophilic substitution reactions and follows the same steps as an electrophilic substitution reaction. Bromination of toluene gives three Bromo toluene products. They are o-bromo toluene, p-bromo toluene and m-bromo toluene. The reaction is represented as: