Two different reactions are taking place here Kolbe–Schmitt reaction and esterification reaction (treatment of the product of Kolbe–Schmitt reaction with (CH3CO)2O(ester).
The two reactions can be written as follows:
1.Kolbe–Schmitt reaction: reaction of phenol with carbon dioxide in the presence of sodium hydroxide, followed by acidification converts phenol to 1−1− hydroxybenzoic acid (Salicylic acid).
2.Esterification reaction: The salicylic acid is then reacted with acetic anhydride (CH3CO)2O)to form aspirin.




