Abstract: Acetylsalicylic acid was synthesized from salicylic acid and acetic anhydride catalyzed by acid bentonites. The structural features of bentonite and the optimum synthesis conditions of acetylsalicylic acid were investigated in details. The results obtained show that the acid bentonites has good catalytic behavior on synthesis of acetylsalicylic acid. The yield rate of 90.44% can be obtained under the reaction conditions as follows: the ratio of salicylic acid and acetic anhydride is 1∶3.6, the ratio of sali...