Question

Is 9-fluorenone and/or 4-methylacetophenone miscible in diethyl ether? Rationalize with the structure of the ketones. Furthermore, when completing a reduction reaction with 4-methylacetophenone using NaBH4, would the product need to be extracted through liquid liquid extraction, or will it precipitate and be extracted through recrystallization. Why would this be true given its structure?

Answer 1

Both the compounds are highly hydrophobic and are expected to be miscible in ether.

There is no specific rule for the solubility of a substance in a solvent. Generally "like dissolves like" is considered as a rule of solubility.

The ketone functional group in both the compounds are non polar in nature. So non-polar substance can be dissolved in a non polar Solvent. So they are miscible in ether solvent.

When the 4-methyl acetyl phenone is reduced by NaBH4, the keto group becomes alcohol which is polar in nature. By adding a suitable polar solvent such as Ethyl acetate or dichloromethane the compound can be extracted by liquid liquid extraction method.

For recrystallization, we need a solvent which dissolves the substance partially at room temperature. We can expect the reduced ketone to be recrystallized from ether also from its structure.