Preparation of Aspirin and IR Spectroscopy

REPORT SHEET

Experiment 7: Preparation of Aspirin and IR Spectroscopy

Name________________                               Date___________

Lab Section____________

 

Draw the reaction scheme for the synthesis of aspirin:

 

 

 

 

 

 

Observations

5.037 g of salicylic acid added into a 125-mL Erlenmeyer flask with magnetic stir bar. 6mL of acetic anhydride with 3-4 drops of concentrated sulfuric acid added to flask and placed in a water bath by clamping the flask to a ring stand and placing a 600-mL beaker under the flask. The beaker filled with two-thirds full of water and heated the system about 25 minutes. Flask removed and rested in ice bath until crystallization completed. After few minute crystals washed with small amount of ice-cold water to remove traces of unreacted acetic anhydride. It took long time to be dry under vacuum and weighted.

When Fecl3 added to salicylic, it turned to dark purple and when Fecl3 added to the sample we weighted it turned to light purple.

Obtained the melting point of sample and used a KBR pellet with ration of 1;1000 to obtain an IR of experimental aspirin

 

 

 

Mass of Salicylic Acid ___5.037 g _______                          Percent yield  ______44.93_____

Calculation of theoretical yield and percent yield:

 

 

Actual/theoretical *100

 

 

2.26/5.03*100

 

Table 1. IR Data Table

Bond or Functional Group Regions	Lit. Salicylic Acid	Lit. Acetic Anhydride	Lit. Aspirin	Experimental Aspirin
OH
O=C-OH
C=O

Ferric Chloride Test Results:

 

 

 

 

 

Melting point data: _____125C________

 

Questions

1. Did you make aspirin? Use the melting point, ferric chloride test, and IR data to support your answer.  Just saying that “they looked the same” is not a sufficient answer.  Include percent error for the IR literature comparisons.

 

 

 

 

 

 

 

 

Yes but there was some errors.  The melting point was lower than the melting point of aspirin and the % transmittance shows that there was OH from water in sample that would be the error happened and means the crystals were not pure and did not dry properly.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. Discuss your % yield.  Was it acceptable?  Unacceptable?

 

 

 

 

No it is not.Its was so low and the main reason is I lost a lot of sample during filtration.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3. Is your aspirin pure? Why or why not?

 

 

 

 

 

No it isn’t. it has OH from water.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4. Was the synthetic method employed an effective method for the preparation of aspirin? Why or why not?