Question

What is the role of ${\mathrm{AlCl}}_3$ in Fridels craft reaction?

Answer 1

Friedel-craft reaction:

1. The reaction between the alkyl halide and acyl halide in the presence of Lewis acid is called the Friedel-craft reaction.
2. The difference between the alkyl group and acyl group reaction is that during alkylation the benzene attack first on the carbon that attracts the electron-rich elements and during acylation, the pi-bond between C-O break first.
3. The reaction between Anisole and Ethanoyl chloride in the presence of anhydrous Aluminum chloride to form 2-Methoxy-acetophenone at ortho and para position with minor and major products.
4. The general reaction of the Friedel-craft reaction is shown below:

The importance of Aluminum chloride in the Friedel-craft reaction is given below:

1. It acts as a Lewis acid that undergoes an electrophile substitution reaction.
2. Aluminum chloride is a covalent compound in which three Aluminum electrons are shared with the three Chlorine atoms through a covalent bond. It acts as an electrophile due to electron deficiency.
3. Lewis acid removes the halide from the alkyl halide and acyl halide and forms carbocation.