MKSStal - 26-12-2016 at 02:41
I have a solvent containing both methyl acetate and acetone. They have very similar boiling points and what is more form an azeotrope with close b.p.
Acetone is miscible with water and AcOMe is about 25g/100g H2O so it want help very much as acetone will dissolve in methyl acetate layer. Any ideas
how to separate those two?
[Edited on 26-12-2016 by MKSStal]
[Edited on 26-12-2016 by MKSStal]
Metacelsus - 26-12-2016 at 07:33
You could try hydrolyzing the methyl acetate, and then separating the acetone from the methanol and acetic acid.
Other than that, I can't think of any good way to separate them.
Tsjerk - 26-12-2016 at 07:38
4A sieves absorp aceton but not methyl acetate.
Cryolite. - 26-12-2016 at 13:58
4A sieves also induce aldol-type polymerization of acetone...
Tsjerk - 26-12-2016 at 23:29
Does it when the acetone itself is absorpted? Can acetone condense when bound to sieves? For that to happen there should be an binding preference for
water over acetone.
JJay - 27-12-2016 at 02:17
I think you could use sodium bisulfite to bind the acetone, distill off the methyl acetate, use alkali to free the acetone, and distill.
MKSStal - 27-12-2016 at 11:03
Do you think that standing over sodium bisulfite even for long time with some shaking might do the work? I don't want to add to the mixture of
solvents: methyl, ethyl and butyl acetates, acetone and methyl ethyl ketone another solvents like water and ethanol.
Tsjerk - 27-12-2016 at 13:07
Bisulfite has to be dissolved to form adducts, if sodium bisulfite is soluble in your system, I'm pretty sure the acetone adduct will also be soluble,
I don't know if these adducts are heat stable enough to survive distillation.
Edit: a bisulfite solution in water just concentrated enough to allow the acetone adduct to fully dissolve in the water could possibly take up the
acetone while salting out the methyl acetate. Or they form one big mixture, also possible.
[Edited on 27-12-2016 by Tsjerk]
JJay - 27-12-2016 at 13:38
You don't have to add any alcohol to form the adducts; just water and sodium bisulfite should be enough.
I don't know how heat stable the acetone-sodium bisulfite adduct is, but you could vacuum distill the acetone if necessary. Right?
[Edited on 28-12-2016 by JJay]
Tsjerk - 27-12-2016 at 22:25
I wonder what the vapour pressure is of acetone above the acetone bisulfite, if any. If there is none vacuum distillation should work.
JJay - 28-12-2016 at 02:35
One vendor reports acetone-sodium bisulfite adduct's melting point as 300 C. *shrug*
Tsjerk - 28-12-2016 at 07:20
OK, then JJay's proposed method should work.
Methyl acetate forms an azeotrope with water at basically its boiling point (56.1 - 57 degrees respectivally) at 95% methyl acetate, but you can dry
the methyl acetate afterwards.