Experiment 1 5t504u

Raeshaun Jones CH 237 – Section 11 February 3, 2014 Experiment 1: Separating the Components of Panacetin and Identifying a Constituent of Panacetin

Theoretical Yield: 10% sucrose, 40% aspirin, 50% unknown Of a 3.00 g sample of Panacetin: 3.00g(10%)=0.3g of sucrose; 3.00g(40%)=1.2g of aspirin; 3.00g(50%)=1.5g of acetanilide or phenacetin Actual Yield: (Original Weight: 3.08g) Sucrose 0.37g/3.08g = 12.0% Aspirin 1.15g/3.08g = 37.3% Unknown 1.55g/3.08g = 50.3% (Amount Recovered: 3.07g) Sucrose 0.37g/3.07g = 12.1% Aspirin 1.15g/3.07g = 37.5% Unknown 1.55g/3.07g = 50.5% Melting Ranges (in degrees Celsius) Unknown (Unk.) 105 – 115 Unk. + Phenacetin 85 – 113 Unk. + Acetanilide 110 – 115 (Acetanilide is the unknown) Results and Discussion: This experiment was enacted to determine the components of “Panacetin” when aspirin and sucrose where the two known components. Either Acetanilide or Phenacetin is the third and final component to make up the mixture. Separation of the components using DCM was first employed. This step separated sucrose from the rest of the mixture. The liquid portion was then combined with NaHCO3 creating two separate layers, an aqueous top layer and an organic bottom layer. The aqueous layer was then combined with HCl and the aspirin portion of the mixture was found using a vacuum. The organic layer was then quickly sent through a machine that evaporated the liquid portion leaving me with the solid unknown. In order to determine the unknown three separate groups (one pure culture, one with unknown and acetanilide, and one with unknown and phenacetin) was placed in a machine and the melting ranges were found. There was a melting decrease in the tube containing phenacetin letting me know that the mixture was not pure, leading to the conclusion that the unknown product is acetanilide. The numbers found from my experiment are within the range of what is acceptable to make this an accurate experiment from the book’s standards. Errors could have occurred in the transferring of the material from one space to another in order to weigh it, and if the vacuum and cooling times were not adequate the sample would have yielded an error. The purity of the unknown leads much to be desired though. With such a wide melting range the purity of it is clearly not as good as we desire. Acetanilide is the most likely unknown component because of the vast difference in 1

Raeshaun Jones CH 237 – Section 11 February 3, 2014 melting range of the mixture containing phenacetin and pure unknown with a much lower starting point. The amount of sucrose recovered was slightly high while the aspirin was low. Questions/Problems Experiment 2, Exercise 2 a. Not allowing for the DCM to fully be mixed into the Panacetin would mean that not all the aspirin and unknown would be taken up. The percent composition would be high for sucrose and low for aspirin and the unknown b. If the aqueous and organic layers were not mixed well then not all of the aspirin would be converted to water soluble. The yield would be too low for aspirin and too high for the unknown. c. Using HCl instead of NaHCO3 would mean that no aspirin would convert to a salt, so the amount of reported aspirin would be low and too high for the amount of unknown. d. Having a pH of 7 instead of 2 would mean that not all of the aspirin would be converted back to insoluble and the soluble salt would be lost in the filtration of the vacuum filtration causing the aspirin reported to be low. Experiment 3, Exercise 3 & 4 3a. If the product was not sufficiently dried before taking the weight then the yield would be raised, and the purity of the unknown lowered. c. If all the aspirin was not extracted from the DCM as a water soluble salt then some would be recovered with the unknown, instead of the aspirin. The purity of the unknown would decrease and the yield would be increased for the unknown. 4a. Decrease; broaden melting point range (added water) b. Decrease; broaden melting point range (added impurities) c. Decrease; broaden melting point range (added aspirin)

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