Question

I need to do an extraction experiment with a mixture of 50% phenanthrene, 40% methyl 4-aminobenzoate and 10% 1,4-dibromobenzene. What solvent should I use? I was thinking about using diethyl ether. After extraction, I plan on doing crystallization with the organic layer using hot ethanol.

Solvents available: diethyl ether, 95% ethanol, methanol, isopropyl alcohol, acetone, hexane, toluene, methylene chloride, and anhydrous sodium sulfate. Which one?

Answer 1

First make your solution acidic by adding HCl to the solution, methyl 4-aminobenzoate becomes water soluble, as it forms ammonium salt, now extract with diethyl ether,

organic layer contains phenantherene and 1,4-dibromobenzene which can be recrystallized from hot hexane to get phenantherene as pure crystals and mother liquor contains mixture of both phenantherene and 1,4-dibromobenzene.

Aqueous layer contains methyl 4-aminobenzoate can be neutralised with NaOH and the extraction with diethyl ether can give pure methy 4-aminobenzoate, then recrystallized with hot alchol.