What is the role of sodium acetate in the acetylation of glucose with acetic anhydride? What is the role of acetic anhydride in the acetylation of glucose?

Answer 1

Acetic anhydride is a widely used acetylating agent. It adds an acetyl group CH₃-C=O to a nucleophilic functional group such as -OH or -NH₂. When it adds to an -OH group, it gives an ester functional group whereas when it adds to NH₂, it forms an amide group.

In the mechanism of acetylation, the -OH group first attacks the electrophilic carbonyl carbon of acetic anhydride. This gives a "protonated" oxygen atom with a net positive charge. The acetate anion helps to deprotonate this oxygen atom resulting in the localization of the electron pair on the oxygen atom giving it a formal charge of zero (neutral).