Sciencemadness Discussion Board

Removing acetone from ethers and other non polars

CrimpJiggler - 17-6-2017 at 13:47

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 - 17-6-2017 at 13:51

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.

tsathoggua1 - 17-6-2017 at 14:00

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 - 17-6-2017 at 16:18

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 - 17-6-2017 at 17:22

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 - 18-6-2017 at 07:25

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 - 19-6-2017 at 08:57

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 - 24-6-2017 at 02:27

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 - 25-6-2017 at 09:32

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 - 26-6-2017 at 06:46

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.