Question

For preparing monoalkyl benzene, acylation process is preferred than direct alkylation because:

• A. in alkylation, a poisonous gas is evolved
• B. in alkylation, large amount of heat is evolved
• C. in alkylation, polyalkylated product is formed
• D. alkylation is very costly

Answer 1

The correct option is C in alkylation, polyalkylated product is formed

When benzene is alkylated, the ring is activated because of presence of $-C{H}_3$ group, so along with mono alkyl benzene, polyalkylation products can be obtained. Hence, instead of direct alkylation, acylation is preferred. Because in acylation , there is prsence of $-COC{H}_3$ group which deactivates the ring and prevents it from further substitution reaction. The acylated product can be hydrogenated to give alkylated product. Hence, the correct answer is option (c).