CrimpJiggler
Hazard to Self
Posts: 75
Registered: 1-9-2011
Member Is Offline
Mood: No Mood
|
|
Removing acetone from ethers and other non polars
I see acetone is miscible with ethers, and even hydrocarbon mixtures so if you got some acetone in there, which makes things like biphase extractions
impossible (is that right?) since its also miscible with water and other polar solvents. How would you go about separating acetone from non polar
solvents like ethers? Lets say I had a mixture of 70% diethyl ether and 30% acetone, if I added water, would two phases form? If so, then I'm guessing
the aqueous phase would contain some of the acetone, so you'd have to repeat the process (adding water and discarding the aqueous phase) repeatedly in
order to get rid of the acetone.
Is my reasoning correct? Also, are there any tricks to make this work better, and additionally are there any other (possibly) better methods of
removing acetone from non polar solvents like ethers and hydrocarbon mixtures?
|
|
|
DraconicAcid
International Hazard
Posts: 4334
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Offline
Mood: Semi-victorious.
|
|
If you had a mixture of ether, acetone and water, you may or may not get two phases, depending on the quantities. Ether does have a low but
measurable solubility in water, and will be more soluble in a mixture of acetone and water. It would be easier to remove the acetone from a
hydrocarbon mixture.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
|
|
|
tsathoggua1
Hazard to Others
Posts: 335
Registered: 8-1-2017
Location: Beyond the pale
Member Is Offline
Mood: Phosphorescent
|
|
Why not add bisulfite in aq. solution, and either filter out the adduct with the ketone if if precipitates from that solvent system. If it doesn't
then form the adduct, leaving it in solution and distill the ether off. That should leave the bisulfite addict of the acetone behind, especially
considering the low BP of EtOEt.
|
|
|
CrimpJiggler
Hazard to Self
Posts: 75
Registered: 1-9-2011
Member Is Offline
Mood: No Mood
|
|
Its only got about 5-10% acetone, the rest is ethers (ethyl + diisopropyl) and naptha. If you excluded the acetone, it would be 33%/33%/33%
EtOEt/IPOIP/naptha. tsathoggua1 nice one, that was the kinda answer I was looking for. I was considering doing a nucleophilic substitution of some
sort, but couldn't think of a decent nucleophile.
I don't have any bisulfite atm. Are there any easy routes to generating it using H2SO4?
|
|
|
JJay
International Hazard
Posts: 3440
Registered: 15-10-2015
Member Is Offline
|
|
I think you can make it from burning sulfur and sodium hydroxide... it's one of the most easily accessible chemicals, available from hardware stores
and brewing stores.
|
|
|
Tsjerk
International Hazard
Posts: 3032
Registered: 20-4-2005
Location: Netherlands
Member Is Offline
Mood: Mood
|
|
I would go for the water washings, the loss of ether should be manageable, while aceton is miscible with water.
The bisulfate route should work nicely as long as you have enough of it and a way to vacuum filter the ether of your adduct without causing the ether
to evaporate too much.
|
|
|
alking
Hazard to Others
Posts: 252
Registered: 11-3-2016
Member Is Offline
Mood: No Mood
|
|
Water washing is the easiest way unless you have a lot of acetone in it as mentioned. If there's too much then forming the adduct is probably the
easiest, if you can't do that another option would be to react it with an acid or base which will cause the acetone to polymerize, it will turn red,
brown, and eventually black, but you'll have to reflux it or wait a day or so at RT. Then you can distill off the ether.
|
|
|
CrimpJiggler
Hazard to Self
Posts: 75
Registered: 1-9-2011
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by DraconicAcid  | | If you had a mixture of ether, acetone and water, you may or may not get two phases, depending on the quantities. Ether does have a low but
measurable solubility in water, and will be more soluble in a mixture of acetone and water. It would be easier to remove the acetone from a
hydrocarbon mixture. |
I got two phases alright. But how much of acetone will remain in the non polar phase is the question. I like the idea of forming the bisulfite adduct,
I just didn't have any bisulfite handy so I didn't get around to trying it. I didn't have a proper sealable container for the volatiles so I had to
let it go. I'll try again another day. God it would be handy to have a freezer I could dedicate to storing volatiles and heat sensitive reagents.
Shaking the layers up, the top or bottom layer would go cloudy (I saw both happen). I'm not that interested in ether (well its a mighty useful solvent
to have, but I don't have the right containers to store it at the moment so I don't intend on procuring it right now), it was just an experiment, I'll
try again another day. Thanks for all the responses, I have a much better understanding of all this now.
[Edited on 24-6-2017 by CrimpJiggler]
|
|
|
tsathoggua1
Hazard to Others
Posts: 335
Registered: 8-1-2017
Location: Beyond the pale
Member Is Offline
Mood: Phosphorescent
|
|
Bisulfite (or more likely, metabisulfite, which ends up as bisulfite in aqueous solution anyhow) is freely available from home brewing stores. Thats
where I got mine from.
Another possibility is forming a NaI adduct. Not sure if KI will substitute, only seen references to NaI, this forms an adduct with carbonyl compounds
which hydrolyses on heating in aqueous solution.
If I'm not mistaken, that mixture..starting fluid? worth checking for other brands. Some contain a mixture of solvents other than diethyl or
diisopropyl ether, acetone, xylene sometimes, naphtha.
Forming an adduct should rid the fluid of acetone, whilst distillation should separate the hydrocarbon fraction, xylene certainly given its high BP.
If it is starting fluid, the hydrocarbon is liable to be heptane, DIPE has a boiling point of 68.5 'C whilst n-heptanes BP is 98.38 'C so unless there
is additional light naphtha in the mixture which could be quite difficult to separate via distillation from an EtOEt/DIPE mixture.
Also-watch it with the diisopropyl ether. Its highly prone to peroxidation. Check it at minimum every 3 months for peroxides. Compare to diethyl ether
which a yearly check is acceptable AFAIK.
And getting a fridge for volatiles is a real good idea. I have one and its a vast improvement on sticking things in a cool dark cupboard. It actually
got bought partly for me, and partly for my old man to store his fishing bait (maggots, casters etc.) and they seem to do fine in a fridge full of
CH2CL2, MeCN and ICl. Wouldn't eat out of it, thats for sure but there can't be too much escape if they are still living considering some of the
things that have been kept in there.
|
|
|
Melgar
Anti-Spam Agent
Posts: 2004
Registered: 23-2-2010
Location: Connecticut
Member Is Offline
Mood: Estrified
|
|
Why not treat with chlorine bleach? Ethers should be stable under those conditions for at least a few hours at room temperature, and acetone, as we
all know, certainly is not. Then just dry the ethers (using your choice of desiccant) after the acetone is done reacting to remove any water that got
in the organic layer.
The first step in the process of learning something is admitting that you don't know it already.
I'm givin' the spam shields max power at full warp, but they just dinna have the power! We're gonna have to evacuate to new forum software!
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
