Question

Which of the following is a method for the preparation of benzaldehyde?

Hint:

The Gattermann-Koch reaction is a useful method for synthesizing aromatic aldehydes like benzaldehyde.

Answer 1

The Gattermann-Koch reaction is a method for preparing benzaldehyde. It involves the reaction of benzene with carbon monoxide and hydrochloric acid in the presence of a Lewis acid catalyst (such as AlCl3). This reaction introduces an aldehyde group (-CHO) to the benzene ring, forming benzaldehyde. Other methods:
- Friedel-Crafts acylation is typically used to form ketones, not aldehydes.
- Reduction of benzoic acid leads to benzyl alcohol, not benzaldehyde.
- Ozonolysis of styrene produces aldehydes or ketones, but not benzaldehyde specifically.
Therefore, the correct answer is the Gattermann-Koch reaction.