Question

What is the major product of chlorination of ethylbenzene?

Answer 1

Chlorination of ethylbenzene:

• During chlorination and in the presence of light or heat, the alkyl side chain is substituted.
• When ethylbenzene reacts with chlorine in presence of light or heat, then it results in the formation of $1-\mathrm{chloro}-1-\mathrm{phenylethane}$ and $2-\mathrm{chloro}-1-\mathrm{phenylethane}$.
• In this reaction, $1-\mathrm{chloro}-1-\mathrm{phenylethane}$ is a major product and $2-\mathrm{chloro}-1-\mathrm{phenylethane}$ is a minor product.

• Chlorination of ethylbenzene in a nucleophilic substitution reaction.
• The stability of the carbocation affects the formation of the major product.
• A more stable secondary carbocation is produced when a nucleophile attacks $\mathrm{\alpha }$ carbon atom.
• Since it is a secondary alkyl halide, $1-\mathrm{chloro}-1-\mathrm{phenylethane}$ is a major product.

Chemical Reaction:

• The chemical reaction is shown below in the image.

Hence, the major product of chlorination of ethylbenzene is $\mathbf{1}\mathbf{-}\mathbf{chloro}\mathbf{-}\mathbf{1}\mathbf{-}\mathbf{phenylethane}$.