Purifying Benzil

[kld84]

A reaction to convert benzoin to benzil using a Cu+2 catalyzed oxidation didn't go to completion. Purify the benzil.

- I was thinking about recrystallizing the benzil, but wasn't sure if that was the best way to purify the benzil and I didn't know what solvent to use.

Thanks!

[Heirtzler]

Hi Kim,

Here are several suggestions for you:

1. Benzoin is likely more soluble in ethanol than benzil. So try

recrystallizing from ethanol.

2. Likely, oxygen will oxidize benzoin to benzil by itself. Maybe even

just the oxygen in the air. In that case, the cupric ion (Cu(II) ) is

really just a catalyst. So maybe just expose your reaction mixture to air,

i.e. leave it stirring. If you're concerned about the slow evaporation of

your solvent, then you can cool them mixture (which will also increase the

solubility of O2 in solvent) and bubble air through it.

Of course this will all depend on the relative amount of benzoin still

present, and its concentration.

Please follow up with us (me)!

regards

Fenton Heirtzler

Dr. F. Heirtzler