Analysis and Optimization of Common Problems in Acetylsalicylic Acid Synthesis Experiment

The synthesis experiment of acetylsalicylic acid is one of the classic experiments offered in undergraduate teaching. To address the numerous problems associated with the use of concentrated sulfuric acid as a classic catalyst in teaching, this paper screens anhydrous sodium carbonate as a suitable catalyst for undergraduate teaching experiments from 14 tested catalysts. Through experimental optimization, the optimal reactant ratio is determined as n (salicylic acid)∶n (acetic anhydride) = 1∶1.8, with a reaction temperature of 80 ℃ and a reaction time of 30 min. The crystallization time is shortened by adjusting the hydrolysis operation steps of acetic anhydride. The analysis of by-products from the two catalysts reveals that anhydrous sodium carbonate produces fewer by-products than concentrated sulfuric acid.