Question

Friedel craft reaction of benzene with isobutyl chloride produces

• A. isobutylbenzene
• B. tert-Butylbenzene
• C. n-Butylbenzene
• D. sec-Butylbenzene

Answer 1

The correct option is B tert-Butylbenzene

Friedel Crafts Alkylation:
In this reaction, one H-atom of the ring get replace by alkyl group. The attacking electrophile is an alkyl carbocation (R+) made available by the reaction of alkyl halide and an anhydrous lewis acid.

Mechanism
Step 1: Formation of electrophile.
Isobutyl chloride react with anhydrous lewis acid $AlC{l}_3$ to form a less stable primary carbocation. Then it undergoes 1, 2 H-shift to form a stable tertiary carbocation which act as an electrophile.

Step 2: Formation of arenium ion
Now, benzene attacks the stable tertiary carbocation to form arenium ion.

Step 3: Removal of $H^{+}$ from arenium ion to form the product


Thus, the product formed after friedel craft alkylation of benzene is tert-Butylbenzene.