Seperating the Components of Panacetin

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Alex Wilson
9/11/12
Experiment #2

Separating the Components of Panacetin:
Introduction:
Of the three components likely to be present in your sample of Panacetin (aspirin, acetanilide, and starch), only starch is insoluble in the organic solvent dichloromethane (or methylene chloride), CH2 Cl2. If a sample of Panacetin is dissolved as completely as possible in dichloromethane, the insoluble starch can be filtered out, leaving acetanilide and aspirin in solution. The purpose of this experiment is to extract the components of Panacetin.

Although the acetanilide and aspirin are both quite insoluble in water at room temperature, the sodium salt of aspirin is very soluble in water but insoluble in dichloromethane. Because aspirin is a reasonably strong acid, it can be converted to the salt, sodium acetylsalicylate, by reaction with the basic sodium hydroxide. While the two layers are thoroughly mixed, the aspirin will react with the sodium hydroxide in the bottom layer, which then migrates to the aqueous layer and can be easily separated in a separatory funnel. Adding some dilute hydrochloric acid to the aqueous solution restores free aspirin as an insoluble white solid; evaporating the solvent from the bottom layer leaves the acetanilide behind.

Experimental:
For the separation of sucrose, we weighed out 3.048g of Panacetin onto a filter, and 50 mL of dichloromethane in a graduated cylinder. Then we transferred both the panacetin and dichloromethane into an Erlenmeyer flask and stirred it until the panacetin was dissolved. We let it dry by gravity and set it aside to dry. The filter paper weighed about 1.320g and sucrose weighed out at 1.028g. Sucrose also ended up on the outside rim of the filter paper. We then proceed to separate the aspirin. We measured 30mL of NaHCO3 and mixed it with 7mL of 6M HCl. We drained the organic layer into a pre-weighed Erlenmeyer flask and save it for recovery of acetanilide. We took the combined aqueous extracts in...
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