Separation of an Acid and Base

Extraction of R’-NH2
For both of the organic acid and organic base extraction, the addition of the respective inorganic acid or inorganic base (HCl or NaOH) to the three-component mixture caused an immiscible appearance of the solution in the separatory funnel. By briskly shaking the separatory funnel with the mixed components created a build up of pressure which was released through the stopcock forming small disappearing bubbles within the tip of the separatory funnel. Once the funnel was placed back into the iron ring and the stopper was removed, the distinct upper ether layer had an oily appearance and a visible barrier separating it from the lower water-organic base or organic acid layer. After pouring out the ether layer into a beaker and adding anhydrous sodium sulfate, all that remained in the funnel was the neutral extract.

Isolation
The preliminary steps in the isolation of the organic acid and organic base required volumes of approximately 10 mL and 8mL respectively of the inorganic acid or base (HCl or NaOH) in order to initiate the cloudy appearance in solution. Vacuum filtration of the NaOH extract (organic acid) produced a shiny white crystalline product collected in the filter paper. Likewise, vacuum filtration of the HCl extract (organic base) produced a dull white crystalline product collected in the filter paper, which was comparable to powdered chalk. After the ether evaporated, the neutral extract remained in the bottom of the beaker and was a mixture of white and slightly tinted green and yellow crystalline product.

Sources of Error

In every scientific experiment there is bound to be experimental error present and this should undoubtedly be accounted for in the analysis of the experiment. A source of error that was unavoidable in this experiment was due to the inability to transfer the entire quantity of recrystallized product from the filter paper to the watch glass. Further experimental error was that some of the water layer containing either the organic base or acid, as a salt, might not have been extracted into the collecting flask. Even though two extractions were performed per substance to be extracted, it was possible that the water layer was not entirely removed, therefore leaving behind some components of the mixture to mix with the ether layer. This could have resulted in a reduction in the purity of the recrystallized products ultimately affecting the melting point of that recrystallized product. Finally, an error due to contamination and poor clean up by a previous group could have resulted in other substances mixing with the organic and inorganic substances that were used in our experiment.