In the Friedel-Crafts reaction, an alkyl halide is used to generate an electrophile (a carbocation) in the presence of a Lewis acid like anhydrous $\text{AlCl}_3$. In chlorobenzene, bromobenzene, and chloroethene (vinyl chloride), the halogen atom is directly attached to an $sp^2$ hybridised carbon atom. Because of resonance, the $\text{C-X}$ bond acquires a partial double bond character, making it very difficult to cleave. Consequently, they do not form carbocations readily. On the other hand, isopropyl chloride is an alkyl halide that readily undergoes heterolytic cleavage to form a stable secondary carbocation, making it a suitable halide component for the Friedel-Crafts reaction.