Separate Neutral Compounds

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In this experiment, extraction was used as a separation technique to separate the acid, base, and neutral compounds. In extraction, two immiscible solvents with different polarities are used to dissolve and separate different solute components, so they form two distinct liquid layers. In this experiment, ethyl acetate, an organic solvent, and an aqueous solution, were used as the two immiscible solvents. The extraction solvent must be capable of dissolving one of the mixture components, without irreversibly reacting with it. While initially it seems as though the organic acid, base, and neutral compounds would never pass into the aqueous layer, the conjugate acid and base of the organic base and acid respectively are soluble in water. The conjugate…show more content…
The two solvents were added to the funnel, and the funnel was capped and the stopcock was closed to avoid spilling of solution. The funnel was then turned over several times for several minutes to let the aqueous and organic layer make contact by increasing surface area of reaction. The stopcock was periodically opened to relieve the air pressure that built up due to gaseous products formed by the reactions. In the first step, HCl was added to the ethyl acetate, which protonated the organic base, forming the base’s conjugate acid, which was polar and hence soluble in the aqueous solution. The aqueous layer was drained, and NaOH was added to neutralize the solution, and deprotonate the conjugate acid to reform the original base, which, as an organic base, was mostly insoluble in an aqueous solution, and precipitated out. Similarly, NaOH deprotonated the organic acid to form a polar water soluble conjugate base. When HCl was added to neutralize the solution, the conjugate base was reprotonated, and the largely insoluble organic acid precipitated out. Sodium sulfate crystals were added to the neutral compound in the organic solvent, because of their hygroscopic property, in order to remove all water from the ethyl acetate solution. The crystals were then filtered out using a piece of cotton with a glass funnel, which ideally trapped and removed all sodium sulfate
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