Synthesis of Aspirin
Name: Xuanyi Li
Teaching associate: Deirdre Zwilling
November 15, 2009
To synthesize aspirin, a common analgesic medicine, via nucleophilic acid-catalyzed substitution reaction of salicyclic acid with acetic anhydride. The whole reaction is catalyzed by phosphoric acid.
(The experiment involved three parts: The activity of acetylsalicylsaure, the isolation and filter of aspirin, and the estimation of the chastity of the last product. )
An assortment of salicylic chemical p (0. 21g, 1 . 52 mmol) and acetic anhydride (0. 52g, 5. 1mmol, 0. twenty four ml) with one drop of focused phosphoric acid solution in a conical vial was heated (50oC) till salicylic acid was dissolved whilst stirring (conical vial was added with a magnetic spinvane and attached with an air condenser). The solution was then heated for another a couple of minutes and cooled to space temperature while the air fondre and spinvane was taken out. The solution was left to crystallize within a beaker of crushed ice although water was added (3. 0mL). The crystals were collected by simply vacuum purification and washed with chilly water (2 x 1 ) 0mL) then let dry out to deliver aspirin (0. 1732, 63%) as solid form. Megapixel. 133-136 oC (lit 134-136 oC).
The reaction of synthesis of aspirin with salicylic chemical p an acetic anhydride with phosphoric acid as catalyst formed acetylsalicylic acid in 63% deliver as transparent solid. The melting point of the crystals was decided to be 133-136 oC, which is within the reported literature range and facilitates the identification of the ideal reaction product. The thin range of the melting level indicated the purity from the compound. The reaction yield could possibly be improved by adjusting how much reactant or perhaps product inside the reaction. For example, by raising the amount of acetic anhydride reactant, the reaction balance will prefer the product, which will produce a increased amount of aspirin deposits. Or, by removing the acetic acid product, the reaction sense of balance...