Cloves contain two principal essential oils, caryophyllene and eugenol. A student carrying out a steam distillation using cloves obtained a mixture of these two oils in the distillate. Explain how the student could separate and isolate the two essential oils using liquid-liquid extraction (hint: phenols are moderately acidic and can be deprotonated by NaOH).

Answer 1

Take the hint. Eugenol is a phenol and the other one is a hydrocarbon; add NaOH to make the Na salt and it will be soluble in water whereas the caryophyllene will more than likley be soluble in ether or some other non-polar solvent. Extract with the two liquids. The Na salt of the eugenol will stay in the water, the other compound will go with the non-polar solvent.