Sciencemadness Discussion Board

ethanol, MEK or MeOH

Jor - 2-5-2011 at 05:37

What would you guys recommend to buy. I am about to buy a liter of ethanol, but I dont want to buy the very expensive duty taxed stuff. So I have the choice of buying it with 5% by weight of MeOH or 2% MEK. I currently have about 400mLs left of EtOH containing 1% MEK, however i only used it for washing inorganic salts and doing some recrystallisations.
Can the MEK be easily removed if I am ever going to perform a reaction where this really interferes? Such as when you prepare a sodium ethoxide solution you would get condensation products right? Would adding half (or more) the volume of aqueous bisulfite solution followed by filtration and distillation give pure 96% EtOH?

Sedit - 2-5-2011 at 05:47

I would go with the MEK tainted stuff since it would be simpler to remove if you really need to. Is there H2O in this Ethanol Jor?

Jor - 2-5-2011 at 15:26

No it's about absolute ethanol from Acros. The problem is that Carl Roth selled a liter aboslute with 1% MEK for only 8 euro, but it seems they have withdrawn that product. :(
So now I have to find an alternative ethanol source.

That is exactly the problem. The MeOH can almost not be removed while the MEk probably can, and it's present in lower concentration, however it does need to be purifed in some reactions as ketones can give those nasty Dies-Alder condensation products.

Lambda-Eyde - 2-5-2011 at 16:04

Quote: Originally posted by Jor  

That is exactly the problem. The MeOH can almost not be removed while the MEk probably can, and it's present in lower concentration, however it does need to be purifed in some reactions as ketones can give those nasty Dies-Alder condensation products.

Surely you mean Aldol condensation, not Diels-Alder reaction? :P

I'd go for the MEK any day. It's less poisonous as well as being easier to separate when needed.