Sciencemadness Discussion Board

Acetone distillation temp?

Fyndium - 25-7-2020 at 03:53

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 - 25-7-2020 at 04:27

Acetone shouldn't form any azeotrope with water (, 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]

Tsjerk - 25-7-2020 at 04:36

How wet is wet? If it is in the 5-10% range you could dry the acetone with some epsom salt or so.

Fyndium - 25-7-2020 at 06:51

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.