Sciencemadness Discussion Board

Electrolysis of cold anhydrous KOH-EtOH solution with iron electrodes

ave369 - 9-7-2015 at 01:12

How will the iron electrodes behave? Will they be oxidized to ferrate, like in the water solution?

MeshPL - 23-8-2015 at 10:18

Why don't you check it yourself?

Also by anhydrous EtOH and KOH you mean absolute ethanol and dry KOH? Not ethoxide or 90% alcohol?

You're not likely to produce ferrates since ferrates are oxidising agents and will likely oxidise ethanol to acetic acid or less likely something else. However high pH may make them less strong.

I'll think about potential reactions on both electrodes and will try to post them soon.

byko3y - 23-8-2015 at 10:45

What you need is potassium ethoxide, KOEt, because equilibrium KOH + EtOH <-> KOEt + H2O exists in the mixture, thus you will have water in your "anhydrous" solution. THe equilibrium constant is close to 1, so [KOH]*[EtOH] = [KOEt]*[H2O].
For the same reason you can't dehydrate ethanol with sodium/potassium - equiibrium will be shifted far to the right ( [EtOH] >> [H2O] ), so pretty much all of the metal that reacted with water and produced KOH/NaOH will be converted into ethoxide and water.
Equilibrium between Ethoxide and Hydroxide Ions in Ethanol

[Edited on 23-8-2015 by byko3y]

ave369 - 7-9-2015 at 14:07

Quote: Originally posted by MeshPL  
Why don't you check it yourself?

You're not likely to produce ferrates since ferrates are oxidising agents and will likely oxidise ethanol to acetic acid


Ethanol has a much lower freezing point than water. Hence, you can have a liquid electrolysis medium cooled by cryohol. -70+ degrees Celsius work magic in preventing ethanol oxidation by ferrate. As far as I know, even -5 degrees Celsius in a 95% ethanol solution is enough to stop the redox reaction right in its tracks.

Why don't I check it myself? Right now I have no carbon dioxide fire extinguishers in my house. Hence, no way to produce cryohol. And the salary is still far away.

[Edited on 7-9-2015 by ave369]