This is a question from my 11th grade textbook, why does the alkylation of benzene with 1-chloropropane gives 2-propyl benzene and not 1-propylbenzene?

Question

Delilah Anderson · Accepted Answer

This I think is an example of Friedel Craft alkylation......

And this usually occurs in the presence of a strong Lewis acid such as #AlCl_3#. i.e. #H_3C-CH_2CH_2Cl + AlCl_3 rarr H_3C-CH_2CH_2^+ + AlCl_4^(-)# And, formally, we gots a primary carbocation.... #H_3C-CH_2CH_2^+# WHICH MAY undergo sigmatropic reaction to give the more stable secondary carbocation....i.e. #H_3C-CH_2CH_2^+ rarr H_3C-stackrel(+)CHCH_3# And the #2^@# carbocation may be the reactive intermediate in the alkylation. Are you happy with this?

Carter Allen · Answer

undefined The alkylation of benzene with 1-chloropropane predominantly yields 2-propylbenzene due to the stabilization of the carbocation intermediate formed during the reaction. The intermediate carbocation undergoes rearrangement via a hydride shift, resulting in a more stable secondary carbocation. This rearrangement leads to the formation of 2-propylbenzene as the major product rather than 1-propylbenzene.