What is the role of acetic anhydride in the acetylation reaction of 4-aminophenol?

In the acetylation reaction of 4-aminophenol, acetic anhydride functions as the acetylating agent. This means that it provides the acetyl group (−COCH3) necessary for the acetylation process. When 4-aminophenol reacts with acetic anhydride, the acetyl group is transferred to the amine functional group of 4-aminophenol, resulting in the formation of acetyl-4-aminophenol.

The significance of acetic anhydride lies in its ability to react with nucleophiles, such as the nitrogen atom in the amine group of 4-aminophenol. This reaction leads to the formation of a more stable acetylated product, enhancing the solubility, stability, and biological activity of the compound.

While the other options refer to possible roles a substance could play in a reaction, they do not accurately describe acetic anhydride's function in this particular context. Understanding the role of acetic anhydride as the acetylating agent is crucial for grasping the mechanism and outcome of acetylation reactions in organic chemistry.