Question

how will prepared asprin

Answer 1

To prepare aspirin, salicylic acid is reacted with an excess of acetic anhydride. A small amount of a strong acid is used as a catalyst which speeds up the reaction. In this experiment, phosphoric acid will be used as the catalyst.

Answer 2

Accurately weigh 3.00 grams of salicylic acid and transfer to a dry Erlenmeyer flask. If you will be calculating actual and theoretical yield, be sure to record how much salicylic acid you actually measured.

Add 6 mL of acetic anhydride and 5-8 drops of 85% phosphoric acid to the flask.

Gently swirl the flask to mix the solution. Place the flask in a beaker of warm water for ~15 minutes.

Add 20 drops of cold water dropwise to the warm solution to destroy the excess acetic anhydride.

Add 20 mL of water to the flask. Set the flask in an ice bath to cool the mixture and speed crystallization.

When the crystallization process appears complete, pour the mixture through a Buckner funnel.

Apply suction filtration through the funnel and wash the crystals with a few milliliters of ice cold water. Be sure the water is near freezing to minimize loss of product.

Perform a recrystallization to purify the product. Transfer the crystals to a beaker. Add 10 mL of ethanol. Stir and warm the beaker to dissolve the crystals.

After the crystals have dissolved, add 25 mL of warm water to the alcohol solution. Cover the beaker. Crystals will reform as the solution cools. Once crystallization has started, set the beaker in an ice bath to complete the recrystallization.

Pour the contents of the beaker into a Buckner funnel and apply suction filtration.

Remove the crystals to dry paper to remove excess water.

Confirm you have acetylsalicylic acid by verifying a melting point of 135°C.