Separation of Three Compounds by Extraction

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Exp. 2 Separation of Three Compounds by Extraction
The purpose of this experiment is do demonstrate the proper procedures of extraction and to develop a practical understanding of this method. In this experiment, extraction is used to separate a known acid, base, and neural compound from each other. The first two compounds undergo proton transfer reactions in the presence of acids or bases. Acids RCOOH, like benzoic acid, was deprotonated to form RCOO-. Bases RNH2, like ethyl 4-aminobenzoate are protonated to form RHN3+. Once the compounds separated into either the aqueous or organic layers, neutralizing the aqueous solution reverses the proton transfer. The major reaction mechanisms are shown below:

The results for this experiment are summarized in the data table below. Compound| Real Comp.| Obs. Comp.| Actual Yield| Theoretical Ratio| Obs. Ratio| Obs.m.p.| Physical Appearance| Ethyl 4-aminobenzoate| .233g| .2093| 89%| 30%| 20%| 89 ° C| Off white appearance; powdery| Benzoic Acid| .233g| .243| 104%| 30%| 20%| 125 ° C| Clear crystals| 9-fluorenone| .311g| .623| 200%| 40%| 60%| 82 ° C| Yellow, filmy,flakes|

Based on the results, the most accurate extraction achieved was the first compound, ethyl 4-aminobenzoate. With an 89% actual yield of the compound, a 3rd or 4th extraction would acid would have yielded more compound, since several extractions with small amounts is more efficient than one extraction with a larger amount. During the first extraction of benzoic acid with NaOH, it was noticeably hard to distinguish the aqueous and ether layer because both were yellow. Since 9-fluorenone is soluble in both the aqueous and organic solutions, it is possible for some of this compound to be present in the aqueous layer. In the second extraction, however, the two layers were clearly defined, and there was not as much 9-fluorenone in the aqueous layer, due to the fact that the...
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