andre178 - 4-2-2011 at 10:19
hi,
I would like to separate ethyl acetate from toluene, both solvents are pure, the etoac is roughly 5% of the toluene.
What is the best way to do this? I tried raising the temperature just slightly above the bp of etoac (77*C) but nothing happened. I have a rotovap
and all the distillation apparati
thank you!
Ozone - 4-2-2011 at 13:11
Toluene does not appear to form an azeotrope with ethyl acetate (if it does, I can't find it easily, and it's not in Lang's). If you distill enough
*toluene* (110.8°C) over, the EtOAc will come with it.
Or, I suppose we could over complicate by adding water, a trace of acid and following the two ternary azeotropes:
water : ethanol : toluene @ 74.4 °C @ 12% w/w water: 37 % ethanol:51 % toluene
water : acetic acid : toluene @ who the hell knows.
Wait...a minute. Was that 77°C at the still head, or in the liquid?
O3
andre178 - 4-2-2011 at 13:17
it was the solution, the still head was 25. It seemed like a straight forward frac dist but it does not work
Ozone - 4-2-2011 at 13:58
That's what I thought. The *head* temperature needs to be at least 77°C before anything will come over. Wrap the column with aluminum foil. By the
time you get toluene (head @ 110°C) your EtOAc should be gone.
Cheers,
O3
andre178 - 4-2-2011 at 14:06
thank you, so to get this straight, the water bath temperature will be pretty high? i might even have to go on and use a flame?
Lambda-Eyde - 4-2-2011 at 14:09
You can't use a water bath for anything that boils at 100 degrees or higher... I thought that was obvious? Normally, water baths are used for
substances with boiling points of less than 80 degrees. You have to use an oil/air/sand bath or a heating mantle.
andre178 - 4-2-2011 at 14:10
yes Lambda, EtOAc boils at 77.
Lambda-Eyde - 4-2-2011 at 14:17
Woops! I only read toluene (110)! My fault. 
Anyways, wrap the column with mineral wool and aluminium foil. Don't use a flame when distilling flammable solvents!