Synthesis of Acetylsalicylic Acid (Aspirin)

513 Words3 Pages
Synthesis of Acetylsalicylic Acid (Aspirin) AINI A.G (2012xxxxxx) 19.03.13 (TUES) Abstract Acetylsalicylic acid was obtained from esterification reaction between salicylic acid and acetic anhydride in 97.40% yield. The product was tested for its purity by ferric chloride test and then identified by its melting point Results and Discussion Acetylsalicylic acid was obtained in 97.40% yield by allowing esterification reaction to occur between salicylic acid and acetic anhydride. Recrystallization of the crude acetylsalicylic acid gave white crystals, m.p. 101-107 0C (lit. 135-1360C [1]). The melting point of white crystals is identified to be lower than the literature melting point of pure acetylsalicylic acid (135-1360C). Melting points are very sensitive to the purity of the organic compound, thus it is possible that may be the crystal lattice of acetylsalicylic acid was disrupted by the presence of an impurity. The most likely impurities are water, acetic acid, or salicylic acid. Water is a common impurity because it is the solvent from which the acetylsalicylic acid is obtained. It would only take a small amount of water to make the melting point lower. As we have more impurities, the melting point will lower and the range of melting will become greater. A pure substance will melt with a small range of 1 to 3 °C while an impure product might melt with a range of 5 to 10 °C or more. The ferric chloride test was done to determine the purity of crystal acetylsalicylic acid. Three test tubes were prepared; Tube 1 contained water and a small amount of crystal acetylsalicylic acid added with a drop of ferric chloride showed the formation of yellow colour solution. Tube 2 which contained water and salicylic acid added with a drop of ferric chloride showed the formation of purple colour solution. Tube 3 or Control only contained water added with a drop of ferric chloride

More about Synthesis of Acetylsalicylic Acid (Aspirin)

Open Document