Which one of the following reactions is most suitable for the preparation of n-propyl benzene

Options

A. Friedel-Crafts alkylation
B. Wurtz reaction
C. Wurtz-Fitting reaction
D. Grignard reaction

Answer

C

Explanation

F.C. alkylation occurs-through carbocation intermediate. Therefore, initially formed n-propyl carbocation undergoes rearrangement by 1,2,-hydride shift to give the more stable isopropyl carbocation.
`CH_(3)CH_(2)CH_(2)-Cl underset(-Cl^(-))overset("Ionization")to underset("n-Propyl carbocation (less stable)")(CH_(3)-CH_(2)-overset(+)(C)H_(2)) underset("Shift")overset(1,2-"Hydride")to underset("Isopropyl carbocation (more stable)")(CH_(3)-overset(+)(C)H-CH_(3))`
thus, F.C. alkylation of benzene with n-propyl chloride can either give exclusively isopropylbenzene or a mixture of n-propyl and isopropylbenzenes depending upon the reaction conditions. In contrast, Wurtz-Fittig reaction does not involve carbocation intermediate but may involve either free-radicals or carbanion intermediates both of which do not rearrange. therefore, n-propyl chloride reacts with benzene in presence of sodium to give n-propylbenzene as the major product.