Introduction
To convert phenol into benzophenone, a multi-step synthesis is required. This process involves the protection of phenol, followed by a Friedel-Crafts acylation reaction.
Step 1: Protection of Phenol
- The hydroxyl (-OH) group of phenol can be protected to prevent it from reacting during the subsequent steps.
- Use a suitable protecting group like trimethylsilyl chloride (TMSCl) to convert phenol into trimethylsilyl phenyl ether.
Step 2: Friedel-Crafts Acylation
- The protected phenol can now undergo Friedel-Crafts acylation with benzoyl chloride (C6H5COCl) in the presence of a Lewis acid catalyst, such as aluminum chloride (AlCl3).
- This reaction involves the electrophilic substitution where the acyl group (C6H5CO-) is introduced onto the aromatic ring, leading to the formation of an aryl ketone.
Step 3: Deprotection
- After the acylation reaction is complete, the protecting group needs to be removed to regenerate phenol.
- This can be achieved by treatment with a base or acidic conditions that can effectively cleave the trimethylsilyl ether.
Step 4: Final Product
- The final product of this reaction sequence is benzophenone (C6H5)2CO.
- This compound can be purified using recrystallization or other appropriate methods.
Conclusion
The overall transformation of phenol to benzophenone involves careful protection, acylation, and deprotection steps to ensure successful synthesis. Each step must be conducted under controlled conditions to achieve the desired product efficiently.