Question

If you are given a mixture consisting of anisole, benzoic acid, and fluorenone how would you devise a method to separate and isolate the two major components of this mixture (anisole and benzoic acid). The possible techniques to be used would be distillation, extraction, or recrystallization.

Answer 1

The boiling point of anisole = 153.8 ^oC, that of benzoic acid = 249.2 ^oC, that of fluorenone = 342 ^oC.

Therefore, the order of boiling points of the three components of the mixture is as follows.

Anisole < benzoic acid < fluorenone

Lower the boiling point, faster it will distillate out from the mixture.

Among the mixture of the above three components in water, anisole solution will be distilled out in the first fraction, benzoic acid solution will be distilled out from the second fraction, and fluorenone solution will be left in the distillation flask.

Now, all the three aqueous fractions can be individually extracted using certain organic solvent (let's say dichloromethane or ethyl acetate).

Now, the individual organic layers will be concentrated using rotary evaporation technique, followed by recrystallization in certain solvent combinations will give the pure individual components.