Question

convert benzene to benzophenone

Answer 1

The most obvious method has been mentioned by others here - the Friedel-Crafts acylation of benzene with benzoyl chloride in the presence of a Lewis Acid (e.g. AlCl3).

It is also possible to produce benzophenone from the reaction of benzene with CO2 under appropriate conditions. Profs. Olah and Prakash observed significant production of benzophenone when trying to optimize the carboxylation of benzene with CO2 under AlCl3/Al catalysis. In this case, you have a Friedel-Crafts carboxylation of benzene with CO2 (which is quite challenging to do!) followed by an in situ acylation with benzene by the intermediate benzoyl cation.

Answer 2

Explanation :

When benzene react with benzyol chloride in the presence of $AlCl_3$ as a catalyst to form benzophnone. This reaction is known as the Friedel-crafts acylation.

Mechanism :

Step 1 : The carbonyl oxygen of acid chloride forms complex with $AlCl_3$. This complex forms acylium ion that behaves as strong electrophile.

Step 2 : The attack of acylium ion on benzene ring results in the formation of arenium ion which is stabilized through denationalization.

Step 3 : In order to regain the aromaticity, the arenium ion undergoes los of proton to form $AlCl_3$  and simultaneously removal of HCl.

By following these three steps, we can get the benzophenone from the benzene.

The reaction are shown below.