Reaction of Benzene with Propene

Friedel-Crafts reaction of benzene with propene in the presence of AlCl₃ gives
A. n-Propyl benene
B. 4-Ethyltaulene
C. Isopropylbenene
D. 2-Ethyltoluene

[KSET 2013]

Friedel-Crafts reaction of benzene with propene in the presence of AlCl₃−HCl as the catalyst at 110°C under high pressure exhibited the highest selectivity for cumene of 99%.

When the propene reacts with the HCl, there are two different ways that the initial stage of the addition reaction could happen.

The secondary carbocation (carbonium ion) is the more stable and forms more readily. Due to more stable carbocation, it is the electrophile that will be attach to the benzene ring and forms cumene (isopropylbenzene).
The chloride ion is immediately picked up by the aluminium chloride to form an AlCl₄^- ion. That prevents the chloride ion from reacting with the carbocation to form chloropropane.


Itroduction of electrophile to benzene ring-


Correct answer is option C. Isopropylbenene also called Cumene

Try to draw the mechanism of this reaction