How would you purify Fluorene contaminated with ethyl-4-aminobenzoate? What method and solvent you would use? Please help...
Fluorene is a polycyclic aromatic hydrocarbon that is soluble in non polar solvents.
Ethyl 4-amino benzoate is soluble is dilute aqueous acids and solvents like ethyl acetate.
If you partition the mixture between cold 0.1 M HCl and a nonpolar solvent, say petrolum ether, in a separating funnel. The aqueous layer will contain the amine and the organic layer the fluorene. Separate. Wash the aqueous layer once with petrolum ether. Combine the organics in a separating funnel and wash the mixture again with dilute acid. Evaporate the organic to recover the fluorene.
If you need to recover the amine. Return the aqueous layer to a separating funnel add base, extract with ethylacetate.
I have just had a few further thoughts. You didn't say how much fluorene you have or the % contamination. If you have a relatively small amount (50 mg - 1g) a small chromatography column would be quick. Pack a small column with silica gel. Take up the mixture in a small volume of petroleum ether (you may need to add a few % of ethyl acetate to get it all in solution). Load onto the column and flush through with petroleum ether. The amine will stick to the origin and the fluorene will pass straight through.
An even sneakier (quick and dirty) way is to dissolve/suspend the mixture in petroleum ether in a beaker and add silica gel. The amine will stick to the silica. Filter the mixture, wash the silica with petroleum ether. Evaporate the pet ether to recover the fluorene.
thank you so much Dr. Russ...yes the question assumes the containment comprises only a small percentage of the mixture...
p.s.: do u happen to know the answer to my other question as well? under the same assumptions...
To purify Fluorene contaminated with ethyl-4-aminobenzoate, you can use a process called solvent extraction. Solvent extraction is a technique used to separate compounds based on their solubility in different solvents. In this case, we need to find a solvent that can selectively dissolve ethyl-4-aminobenzoate while leaving Fluorene behind.
Here's how you can purify Fluorene contaminated with ethyl-4-aminobenzoate:
1. Choose a suitable solvent: Start by selecting a solvent that can dissolve ethyl-4-aminobenzoate but has minimal solubility for Fluorene. In general, polar solvents are good for extracting polar compounds like ethyl-4-aminobenzoate. Common solvents that can be used include methanol, ethanol, or acetone.
2. Dissolve the mixture: Dissolve the Fluorene contaminated with ethyl-4-aminobenzoate in a minimal amount of the chosen solvent. Stir the mixture to ensure proper mixing.
3. Extract the compound: Once the solution is prepared, transfer it to a separatory funnel. Add an appropriate volume of the solvent to ensure efficient extraction. Shake the funnel gently to allow the two compounds to separate into distinct layers.
4. Separate the layers: Allow the layers to settle so that a clear separation between the organic and aqueous phases occurs. The ethyl-4-aminobenzoate will preferentially dissolve into the solvent, while Fluorene will remain in the organic phase.
5. Collect the organic phase: Carefully drain the lower organic phase (containing Fluorene) from the separatory funnel into a clean container. This step separates the two compounds.
6. Recover the solvent and purify Fluorene: To obtain purified Fluorene, the solvent needs to be removed from the organic phase. One method is to evaporate the solvent under reduced pressure, such as using a rotary evaporator, leaving behind the purified Fluorene.
It is important to note that the effectiveness of solvent extraction depends on several factors, like the solubility of the compounds, their ratio in the mixture, and the chosen solvents. If necessary, repeat the process or consider using alternative purification methods like column chromatography or recrystallization for further purification.