It is also readily soluble in boiling water, but it is sparingly soluble in cold water (E. Gildemeister, 1913). Acetylvanillin will be formed via esterification of vanillin in a basic solution. Procedure1 In this experiment, vanillin will react with the acetylating agent acetic anhydride to form the acetate ester of the phenolic hydroxyl group. Dissolve the vanillin (3. 04 g, 0. 020 mole) in 1 M aqueous potassium hydroxide (22ml, 0. 022 mole) in a 125 ml Erlenmeyer flask. Add it to acetic anhydride (2. 1 ml, 2. 27 g, 0. 022 mole) in ether (45 ml).
Stir the mixture until it loses its yellow color and the lower, aqueous layer becomes almost colorless. Pour the mixture into a separatory funnel and draw off the aqueous layer. Decant the ethereal solution into an Erlenmeyer flask and dry the solution with anhydrous magnesium sulfate. Remove the drying agent by gravity filtration into another Erlenmeyer flask. Using the steam bath, strip off the all the ether and allow the residue of acetylavanillin to cool to crystallize. As the final procedure, Recrystlaize the crude product from 40 ml of 50% ethanol in water.