A. Dows process
B. Friedel & Craft acylation
C. Friedel & Craft alkylation
D. Clemmenson reduction
¨ C. Friedel & Craft alkylation is the replacement of hydrogen of benzene by an alkyl group in the presence of an alkyl halide and aluminum chloride.
¨ Friedel & Craft alkylation is an electrophilic substitution reaction that involves the addition of an alkyl group to the benzene ring. The reaction is carried out by treating benzene with an alkyl halide (such as R-Cl or R-Br) in the presence of a Lewis acid catalyst, such as aluminum chloride (AlCl3).
¨ The reaction mechanism involves the formation of a carbocation intermediate, which is generated by the interaction between the alkyl halide and the Lewis acid catalyst. The carbocation intermediate then undergoes electrophilic attack by the benzene ring, forming a sigma complex, which then undergoes deprotonation to form the final product.
¨ For example, the reaction of benzene with ethyl chloride in the presence of aluminum chloride catalyst can be represented as:
¨ C6H6 + CH3CH2Cl → C6H5CH2CH3 + HCl
¨ The product of the reaction is ethylbenzene, which is an important intermediate in the production of various chemicals and polymers.
¨ Therefore, the replacement of hydrogen of benzene by an alkyl group in the presence of an alkyl halide and aluminum chloride is known as Friedel & Craft alkylation.
Submitted by :- Jamil Ahmed