Analysis and Optimization of Common Problems in the Synthesis Experiment of Acetylsalicylic Acid

The synthetic experiment of acetylsalicylic acid is one of the classical experiments offered in undergraduate course teaching. In order to solve many problems in using classical catalyst concentrate sulfuric acid, in this paper, we obtained the most suitable catalyst sodium carbonate for the undergraduate experiments by screening from the tested 14 kinds of catalysts. The optimum reactant ratio was n (salicylic acid)∶n (acetic anhydride) = 1∶1.8, the reaction temperature was 80 ℃, and the reaction time was 30 min. And the crystallization time was shortened by adjusting the hydrolysis steps of acetic anhydride. Furthermore, the analysis of the by-products of the two catalysts found that sodium carbonate anhydrous was less by-products when it was used as catalyst than concentrated sulfuric acid.