synthesis of aspirin

        Variables(Independant): The substances mixed with Ferric Chloride solution.

        (Dependant): Pureness

        (Controlled): amount of ferric chloride solution, amount of distilled water, clean test tubes.

Planning B

        Chemicals:

• Acetic anhydride
• Salicylic acid
• 85% phosphoric acid

        Materials:

• 125 mL Erlenmeyer flask
• 5 mL or 10 mL graduated cylinder
• 600 mL beaker
• 400 mL beaker
• thermometer
• burner
• suction flask
• buchner funnel
• vertical upright
• extension clamp with clamp holder
• top loading balance
• test tube with cork
• split cork to hold thermometer

        

        Method:

• Warning: Be careful when using Acetic Anhydride and Phosphoric Acid. Both chemicals can cause serious burns. Use gloves when handling and use in hood.
• Using a top loading balance to approximately weigh 1.50 grams of salicylic acid to the nearest 0.01 grams. Place the salicylic acid in a 125 mL Erlenmeyer flask.
• Measure 3.00 mL of Acetic Anhydride in a 5.00 mL graduated cylinder.
• Add the acetic anhydride to the salicylic acid in the flask. Use the acetic anhydride to wash down any salicylic acid remaining on the side of the flask. Swirl the flask gently.
• Add 10 drops of 85% phosphoric acid to the flask.
• Fill a 600 mL beaker half way. Heat up to 85 degrees C. Place the flask in the beaker to heat up for 5 minutes.
• Immediately add 3.00 mL of distilled water to  flask while the reaction is still hot.
• Once decomposition is complete, add 25.0 mL of distilled water to rinse down the inside of the flask. Swirl flask until solution mixed. Place flask in ice water bath and stir until crystallization begins. Let flask stand for 15 minutes until crystallization is complete.
• Filter product using suction flask. Wash three times with 15.0 mL portions of cold water. After suction, pull air through the product to remove excess moisture.  Continue filtering for about 15 minutes to enhance drying.
• Label and weigh a clean watch glass.
• Transfer product on watch glass then place in oven at less than 90 degrees C for 10-15 minutes. Remove watch glass from oven and let cool at room temperature. Weigh and record watch glass and product.
• Place cooled watch glass back in oven for 10 minutes. Remove, allow to cool and record mass again. If the two weights are 0.05 grams or less apart, then product is dry. If not, then repetition of heating and weighing must continue until products agree to 0.05 grams or less.
• Place dry product in a labeled test tube.
• Obtain three small test tubes
• Into the first test tube, add a few crystals of salicylic acid and 5.00 mL of distilled water. Now add a few crystals of your aspirin and 5.00 mL of distilled water in the second test tube. In the third test tube, add a little of crushed commercial aspirin and 5.00 mL of distilled water.
• Once the crystals dissolved, add one drop of Ferric Chloride to each test tube. Observe and record the color changes.

Data Collection

        

Data Analysis

        Actual Yeid of Crude Aspirin:

        Theoretical Yield:

        Percen Yield:

Evaluation