Question

Acetophenone is prepared from:
A. Rosenmund reaction
B. Sandmayer reaction
C. Wurtz reaction
D. Fridel craft reaction

Answer 1

Hint: Acetophenone is considered as a carbonyl compound in which we see that the ketone is attached to the benzene ring. To form the acetophenone we use the catalyst called anhydrous aluminium chloride. So the reaction which carries out the formation of acetophenone is an electrophilic substitution reaction.

Complete step by step solution:
We can form the acetophenone which is also known as methylphenyl from benzene by the friedel craft reaction. There are two types of friedel craft reaction which are the alkylation and acylation reactions. The friedel craft acylation reaction is a convenient reaction which is used widely for the preparations of the aromatic ketones in which we observe that the ketonic groups get directly attached to the aromatic ring. This reaction shows the treatment of the aromatic hydrocarbon with the acid halide in the presence of the acid called the Lewis acid such as aluminium chloride.

Here to get acetophenone as the product we react the benzene with the acyl halide in the presence of the catalyst called anhydrous aluminium chloride which tends to give the acyl benzene as the product. So firstly we would react with the ethanoyl chloride with the aluminium chloride which gives us the electrophile. Now this formed electrophile tends to react with the benzene ring which undergoes the reaction of electrophilic substitution to form the product called acetophenone. The reaction is the following:
${C_6}{H_6}$$+$$C{H_3}COCl\xrightarrow{anhydrous\;aluminium\;chloride} {C_6}{H_5}COC{H_3} +HCl$
So here we see from the above reaction that the acetophenone is formed by the friedel craft reaction(acylation).

Hence the correct answer is option D.

Note: The limitations of the friedel craft acylation is that it only forms ketones because the formyl chloride tends to decompose into CO and HCl when they get exposed to certain conditions. The aromatic compounds do tend to react in the reaction if it is less reactive than the given monochlorobenzene. The use of aryl amines is prohibited because they tend to form the unreactive complexes with the Lewis acid catalyst.