Question

I have posted the procedure of the lab below. Please tell me what the theoretical yield is for aspirin based on this procedure and explain how you got it. I am not sure I am doing this right.

SYNTHESIS OF ASPIRIN

Procedure:

1. Start heating a water bath in your 250 mL beaker by filling it with ~150 mL of tap water.

2. Carefully weigh out 1.0 gram of salicylic acid. Transfer to a 50 mL Erlenmeyer flask.

3. In the fume hood, add 3.0 mL of acetic anhydride to the flask.

4. Add 3 drops of phosphoric acid to the flask.

5. Clamp the flask so that it is in the water bath. Continue heating the water bath to a boil. Stir the contents to dissolve the rest of the salicylic acid, if needed.

6. Once the water boils, turn off the heat and keep the flask in the water bath for 10 minutes.

7. After the 10 minutes, leave the flask in the water bath and slowly add ~1 mL of DI water to the flask to decompose any excess acetic anhydride.

8. After a minute, remove the flask from the water bath and add 10 mL of DI water. Let the flask cool to room temperature. If crystallization has not occurred, scratch the inside of the flask with a spatula to initiate crystallization.

9. Once crystals have begun to form, cool the flask in an ice bath for 15 minutes or until no more crystals form. Also, chill 10-15 mL of DI water in a small beaker.

10. Weigh a piece of filter paper on a watch glass before beginning the filtration process.

11. Collect the crystals using vacuum filtration.

12. Rinse the flask with about 5 mL of ice water and transfer the mixture to the funnel. Wash the crystals with 2 additional 1 mL portions of ice water.

13. Dry the crystals in an oven for 10 minutes.

14. Weigh the crude crystal, filter paper and watch glass.

15. Warm ~15 mL of DI water (no higher than 70 °C)

16. Add 5 mL of ethanol to a 50 mL beaker and transfer the crude crystals into the beaker.

17. Gently warm (do not boil) the beaker until the crystals dissolve and immediately take off the heat.

18. Add the 15 mL of warm water to the beaker and cool to room temperature.

CHM 2370 Rev 8/2019

19. Cool the mixture in an ice-water bath for 10 minutes. If crystallization has not occurred, scratch the inside of the flask with a spatula to initiate crystallization. Also, chill 10-15 mL of DI water in a beaker.

20. Weigh a piece of filter paper on a watch glass before beginning the filtration process.

21. Vacuum filtration using a Büchner funnel.

22. Rinse the flask with about 5 mL of ice water and transfer the mixture to the funnel. Wash the crystals with 2 additional 1 mL portions of ice water.

23. Dry the crystals for 5 minutes by allowing air to drawn through them while they remain in the funnel.

24. Transfer the product with the filter paper to a pre-weighed watch glass.

25. Dry in your drawer until the next lab. You want a dry product in order to get a good IR.

26. Next lab, weigh the watch glass, filter paper and pure product.

Calculations

• Calculate the theoretical yield of aspirin

no data is required to find the THEORETICAL yield.

all you need is the procedure

Answer 1