I did an experiment in lab where we isolated eugenic from clove oil using acid b

Question

I did an experiment in lab where we isolated eugenic from clove oil using acid base extraction and I just do not understand why we added certain chemicals to isolate it and why we added the chemicals in the specific order that they were in. Summary of the experiment is below We added oil with diethyl ether and then NaOH in separator funnel. I understand the NaOH was used to deprotonate the eugenic but what was the purpose of the diethyl ether? I then drained out the lower aqueous layer into a beaker and added HCI to the drained out solution which I know was used to protonate the eugenic. We then added diethyl ether again but what did the diethyl ether do? Next I added the above solution back into the separator funnel containing the previous aqueous solution. Diethyl ether was again added and the extraction procedure was repeated and finally the diethyl ether was removed by hot plate. Basically, what was the purpose of the diethyl ether and can you please go in a little more depth into what was happening in the experiment? Thank you so much

Explanation / Answer

Your oil will not be soluble in water but would be soluble in diethylether..

So we add diethylether as a solvent to dissolve oil. When you add NaOH oil forms ionic species which goes in water layer. You separate the water layer and acidify with HCl to reprotonate the salt of oil to neutral oil. Again once neutral your oil will be insoluble in water, so you add diethylether here. This you can judge well as you are extracting your oil from water by adding diethylether, which tells that your oil has greater solubility in diethylether than in water. finally the total diethylether phase collected is dried (I suppose you might have added a drying agent as Na2SO4 or MgSO4) and solvent diethylether is removed to isolate the oil.

The overall experiment is purification of oil. You have initial sample of oil with soluble impurities in it. When you add NaOH, you specifically deprotonate the oil which goes in water, leaving behind the soluble impurities in the diethylether layer. Reacidification and extraction of oil from aqueous phase gives you the pure oil fraction from the sample.

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