How do you recrystallize naphthalene and maleic anhydride?

1 Answer
May 2, 2017

This is the province of experiment...........


When you recrystallize something, what works, works. And there is really no way we can predict what is going to work. This being said, most organic chemists have had a lot of success using hot ethanol. Because this is a water-like solvent, organic solutes should not have too great a solubility in the COLD solvent. The high boiling point of ethanol gives you a good temperature range. Also (and importantly), ethanol is none too flammable; meaning that I could use a heat gun on a flask of ethanol. I would not do so on a flask of hexanes.

Chloroform is a much more powerful solvent than ethanol, but this means that the crystals MAY NEVER come out of solution (if you can get them into solution in the first place). Sometimes you can layer such a solvent with say hexanes or pentane, and crystals form as the layers slowly mix.

I think you will find that naphthalene and maleic anhydride to be stubborn beasts. Can you sublime them? I have a vague recollection that you can. You will have to heat it fiercely. You lose a lot of mass in a sublimation, but the sublimate (so-called) that you do recover is usually very pure.