Synthesis of acetylsalicylic acid

• Main Author: Chan, Stephanie C.
• Format: text
• Published: Animo Repository 2011
• Subjects: Aspirin—Synthesis; Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/13402
• Institution: De La Salle University

The purpose of this experiment was to produce acetylsalicylic acid through an esterification reaction. The reaction involves salicylic acid and acetic anhydride in the presence of phosphoric acid to produce acetylsalicylic acid and acetic acid as the by-product. The product was recrystallized using hot water to remove insoluble impurities. The synthesized product was analyzed via melting point analysis, solubility test, thin layer chromatography, IR and ESI-MS. The results were compared with the commercial aspirin, The melting point of the synthesized aspirin and commercial aspirin were 126.2-146.4 oC and 135.2 oC, respectively. Compared with the literature value of 128-137oC, the three values were fairly close. Both samples were found to be insoluble in water and slightly soluble in toluene. Moreover, based on TLC, no trace of the initial reactant was found on the synthesized aspirin based on the spot it travelled. Furthermore, the major peaks expected based on the structure of the compound in the IR spectra were present. Lastly, the ESI-MS result gave an [M+Na] of 203.0318, which confirms that the product obtained was acetylsalicylic acid. From these results, it can be asserted that the experiment was indeed successful with a calculated percent yield of 70.9%.