Synthesis of Aspirin Lab

Summary

This video demonstrates the process of making aspirin (acetylsalicylic acid) from salicylic acid and acetic anhydride. The procedure involves weighing the ingredients, mixing them in an acidic environment, and heating the mixture. After the reaction, cold water is added to form aspirin crystals, which are then filtered using a suction filtration system. The aspirin is recrystallized with alcohol and warm water, followed by another filtration to isolate pure aspirin. The final product is air-dried, weighed, and presented with a close-up view of the crystals.

Takeaways

• 😀 The goal of the procedure is to make acetylsalicylic acid (aspirin) using salicylic acid and acetic anhydride.
• 😀 2.27 grams of salicylic acid is weighed out for the reaction.
• 😀 Between 4 to 5 milliliters of acetic anhydride is added to the salicylic acid.
• 😀 The mixture is swirled to ensure all the salicylic acid is dissolved in the acetic anhydride.
• 😀 Five drops of concentrated sulfuric acid are added to create an acidic environment and accelerate the reaction.
• 😀 The reaction is heated in a boiling water bath for 10 minutes until the solution takes on a yellowish-brown tint.
• 😀 After heating, 10 milliliters of cold water is added to the reaction mixture.
• 😀 The aspirin crystals are allowed to form in a cold water bath.
• 😀 The aspirin is then filtered using a sidearm flask, suction filter, and aspirator to create low pressure for efficient filtration.
• 😀 Ethanol is used to rinse the aspirin crystals, which helps remove impurities and ensures a pure product.
• 😀 The aspirin is recrystallized by dissolving it in warm water to form larger, purer crystals, which are then filtered and dried.

Q & A

What is the main objective of this experiment?

The main objective of the experiment is to synthesize aspirin (acetylsalicylic acid) by combining salicylic acid and acetic anhydride in an acidic environment, followed by crystallization and purification.

How much salicylic acid is used in the experiment?

The experiment uses 2.27 grams of salicylic acid, which is recorded before starting the process.

Why is acetic anhydride added to the salicylic acid?

Acetic anhydride reacts with salicylic acid to form aspirin, and it also provides an acidic environment that facilitates the esterification reaction to form acetylsalicylic acid.

What role does concentrated sulfuric acid play in the experiment?

Concentrated sulfuric acid is added to create an acidic environment and to accelerate the esterification reaction between salicylic acid and acetic anhydride.

How long is the mixture heated in the boiling water bath?

The mixture is heated for 10 minutes in the boiling water bath, which causes the reaction to proceed and results in a yellowish-brown color change.

What is the purpose of adding cold water after heating the mixture?

Adding cold water cools the mixture and helps in the precipitation of aspirin crystals from the solution.

Why is a suction filtration setup used in this experiment?

A suction filtration setup is used to separate the aspirin crystals from the solution by creating a low-pressure environment that helps to pull the liquid through the filter, leaving the solid aspirin behind.

Why is ethanol used to rinse the aspirin crystals?

Ethanol is used to rinse the aspirin crystals to help purify them by removing any residual impurities and to aid in recrystallization.

What is the purpose of recrystallizing the aspirin?

Recrystallization helps to purify the aspirin by dissolving it in warm ethanol and allowing it to crystallize again, resulting in larger, purer crystals of acetylsalicylic acid.

How is the purity of the final aspirin product ensured in the experiment?

Purity is ensured by filtering the aspirin crystals, rinsing them with ethanol, and recrystallizing them from a warm solution. Additionally, the dried crystals are weighed to check for any remaining impurities.