For the aspirin synthesis and many syntheses involving the acetylation of a phenol hydroxy group I noticed that along with the acetic anhydride there is often sodium acetate present. When thinking about the aspirin synthesis it just made sense to me to have the hydroxybenzoic acid in solution with acetic anhydride and maybe some acid catalyst. Why have two equilibrium conditions going by adding some acetate ions also?
I cant wrap my head around it, could it possibly function as a reaction regulator? slowing down the reaction to avoid a largely exothermic reaction?