SuperOxide
Hazard to Others
Posts: 487
Registered: 24-7-2019
Location: Devils Anus
Member Is Offline
|
|
Using calcium chloride to remove MeOH from EtOH - Is it possible?
I've used anhydrous calcium chloride as a desiccating agent for a while since it not only complexes with water, but also alcohols. But I just found this quora answer that suggests anhydrous calcium chloride can be used to purify EtOH by removing only the MeOH.
| Quote: | | Ethyl alcohol can be separated from methyl alcohol chemically by adding anhydrous calcium chloride which forms complex with methanol but not
with ethanol. Then the crystalline complex may be filtered and heated to get back methanol while the residue of the filtration remains as
ethanol |
I thought both EtOH and MeOH form complexes with CaCl2... Has anyone tried this before?
|
|
|
Fyndium
International Hazard
Posts: 1192
Registered: 12-7-2020
Location: Not in USA
Member Is Offline
|
|
To be honest, Quora would be one of the less credible source in my opinion. I've seen multitude of suggestions, speculation and second guessing with
things that are far away from facts that I knew of.
But, for the matter, separating IPA and ethanol would be a more interesting venture.
|
|
|
clearly_not_atara
International Hazard
Posts: 2799
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
I doubt that separating MeOH from EtOH is easier than decarboxylating lactic acid. Apparently this can be achieved by photolysis:
https://pubs.rsc.org/en/content/articlelanding/2021/CP/D0CP0...
|
|
|
SuperOxide
Hazard to Others
Posts: 487
Registered: 24-7-2019
Location: Devils Anus
Member Is Offline
|
|
Quote: Originally posted by Fyndium  | | To be honest, Quora would be one of the less credible source in my opinion. I've seen multitude of suggestions, speculation and second guessing with
things that are far away from facts that I knew of. |
Yeah... I agree. I guess it was just hopeful thinking,
lol.
Right, but I can easily
get/purify IPA, so thats not an issue. The ethanol I have and can easily get is usually denatured with MeOH (and a few other things that are easier to
remove).
|
|
|
Fyndium
International Hazard
Posts: 1192
Registered: 12-7-2020
Location: Not in USA
Member Is Offline
|
|
Would it be enough to fractional distill the methanol off from ethanol? They generally have similar properties as a solvent, so traces of neither
would not be too critical.
|
|
|
Tsjerk
International Hazard
Posts: 3032
Registered: 20-4-2005
Location: Netherlands
Member Is Offline
Mood: Mood
|
|
Methanol is more acidic than ethanol, therefore magnesium reacts faster with methanol than with ethanol. You could stir magnesium shavings with dilute
HCl to clean it, rinse with water, and stir it with dryish alcohol. Then you distill and you will have anhydrous alcohol with less methanol.
You will get an equilibrium between methoxide and ethoxide, but with e.g. 1% methanol and 99% ethanol and with let's say ten times the magnesium to
react with the methanol you will take out 99%+ of the methanol.
You could use the (m)ethoxide to dry ethanol where a bit of methanol doesn't matter.
|
|
|
SuperOxide
Hazard to Others
Posts: 487
Registered: 24-7-2019
Location: Devils Anus
Member Is Offline
|
|
| Quote: Originally posted by Fyndium | | Would it be enough to fractional distill the methanol off from ethanol? They generally have similar properties as a solvent, so traces of neither
would not be too critical. |
If it was for a solvent then just getting rid of the water would be sufficient, but I actually have a few experiments that I would like to try with
pure ethanol. diethyl oxalate, sodium ethoxide, etc.
| Quote: Originally posted by Tsjerk | Methanol is more acidic than ethanol, therefore magnesium reacts faster with methanol than with ethanol. You could stir magnesium shavings with dilute
HCl to clean it, rinse with water, and stir it with dryish alcohol. Then you distill and you will have anhydrous alcohol with less methanol.
You will get an equilibrium between methoxide and ethoxide, but with e.g. 1% methanol and 99% ethanol and with let's say ten times the magnesium to
react with the methanol you will take out 99%+ of the methanol.
You could use the (m)ethoxide to dry ethanol where a bit of methanol doesn't matter. |
Hmm... That's an interesting idea. I have like 30g of magnesium ribbon. I have more magnesium powder than I do ribbon though. But I know the magnesium
+ alcohol is exothermic, so adding powder might not be the best idea.
|
|
|
Tsjerk
International Hazard
Posts: 3032
Registered: 20-4-2005
Location: Netherlands
Member Is Offline
Mood: Mood
|
|
If you have a reflux apparatus you could use that to do the alcohol/magnesium reaction in. I don't think the reaction with magnesium powder would be
so vigorous you can't handle the possible boiling with some cooling water. But of course don't start with all powder at once to be sure.
|
|
|
SuperOxide
Hazard to Others
Posts: 487
Registered: 24-7-2019
Location: Devils Anus
Member Is Offline
|
|
| Quote: Originally posted by Tsjerk | If you have a reflux apparatus you could use that to do the alcohol/magnesium reaction in. I don't think the reaction with magnesium powder would be
so vigorous you can't handle the possible boiling with some cooling water. But of course don't start with all powder at once to be sure.
|
Right. I only have 1 liebig condenser, which isn't super efficient. I have a friedrich condenser on my to-buy list. I may buy that first, just to be
safe, lol.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
