Acetylation of compounds containing the amino or hydroxyl group is usually accomplished by means of — Physical Chemistry — Thermodynamics Chemistry Question

Acetylation of compounds containing the amino or hydroxyl group is usually accomplished by means of acetyl chloride or acetic anhydride. The reaction is catalyzed by a catalyst such as pyridine or sulfuric acid.

Aspirin may be prepared from salicylic acid and acetic anhydride. Sulfuric acid is frequently used as a catalyst in this reaction.
HOC₆H₄COOH + (CH₃CO)²O +H
CH₃COOC₆H₄COOH + CH₃COOH

Procedure
In a 125 cm 3 Erlenmeyer flask place 3.5 g of salicylic acid, 3.5 cm 3 of acetic anhydride (density: 1.08 g/cm 3 ), and 5 drops of concentrated sulfuric acid (some heat may be generated). Heat the flask in a hot water bath and stir for 5 minutes. During this time, the solid dissolve completely.
Remove the flask from the bath and add 15 cm 3 of ice water to it. Cool the flask to crystallize the products. Collect the crystals by suction filtration.
Transfer the crystals to a 125 cm 3 Erlenmeyer flask, add 8 cm 3 of ethanol. Heat the flask in a water bath until the solid has dissolved. Add 20 cm 3 of hot water to the flask and heat it until the solution clears. Remove the flask from the bath, cover it, and allow it to cool at room temperature. Collect the needle–like crystals by suction filtration. Wash the crystals with cold water and allow it to dry thoroughly.
Weight the crystals obtained and calculate the percentage yield of this experiment.
Determine the melting points of the products.