Fyndium
International Hazard
Posts: 1192
Registered: 12-7-2020
Location: Not in USA
Member Is Offline
|
|
Acetone distillation temp?
I think I should get back to basics for now, because I got a little confused. I've used to expect acetone is very easy to separate from water and
other impurities, but now I have to ask this probably very beginner question.
When I was distilling wet acetone, it started to come over as usual at 56-58 and it stayed there for most of the part, but it slowly creeped up to
61-62 and at the end it raised to 70. So do I only collect the fraction that distills at 56-ish C? This would result in huge losses,
because probably only half of the input acetone will distill at this temp. I suppose it should be ran under fractional reflux to get all water our?
I suspect that wet acetone might be the reason why my isomerization failed. If there is water present, it will go all wrong. I dried acetone with
calcium sulfate prior and it did not clump, but it is somewhat hard to say because it always forms a mud.
|
|
|
Fulmen
International Hazard
Posts: 1716
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
Acetone shouldn't form any azeotrope with water (https://en.wikipedia.org/wiki/Azeotrope_tables), and the difference in BP should make it fairly easy to separate. A fractional column should
improve yields though, as the pot concentration drops more water will come over. I would keep the 56-fraction as pure and keep the "tails" as a crude
product for either re-distillation or non-critical use.
[Edited on 25-7-20 by Fulmen]
We're not banging rocks together here. We know how to put a man back together.
|
|
|
Tsjerk
International Hazard
Posts: 3032
Registered: 20-4-2005
Location: Netherlands
Member Is Offline
Mood: Mood
|
|
How wet is wet? If it is in the 5-10% range you could dry the acetone with some epsom salt or so.
|
|
|
Fyndium
International Hazard
Posts: 1192
Registered: 12-7-2020
Location: Not in USA
Member Is Offline
|
|
Wet in this instance is anything between 10 to over 50%, meaning the cetone is extracted from waterous residues or from a reaction that has water as
one component.
I was thinking of getting or making as pure as possible acetone for isomerization and use crude for reactions that are not water sensitive.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
