Question

Calculate theoretical and percent yield.

In this experiment, salicylic acid and acetic anhydride will be reacted to form acetylsalicylic acid in an acid catalyzed reaction. In a reaction tube, add approx. 140 mg salicylic acid, a boiling chip and a small drop of 85% phosphoric acid. Add 0.3mL acetic anhydride, which should wash the reactants to the bottom of the tube. Mix thoroughly. Heat in a beaker of water at 90oC for 5 min. Cautiously add 0.2 mL water to the reaction mixture to decompose the excess anhydride. This reaction is extremely exothermic. When the reaction is complete, add 0.3mL water and allow the tube to cool slowly tor room temperature. The product should crystallize from the reaction mixture. If it doesn’t, scratch the surface of the glass to initiate crystallization. Cool in ice for at least 10 min to complete crystallization. Remove the solvent with a pipet. If the crystals are too fine, collect the crystals by vacuum filtration on a Hirsch funnel. Complete the transfer with a very small quantity of ice water. Turn the product onto a piece of filter paper and squeeze the crystals between pieces of filter paper to absorb excess water. Allow product to air dry before collecting the mass, IR spectrum and melting point temperature

Salicylic acid added- 0.149g

Mass recovered-0.034g