Sciencemadness Discussion Board

Electrolysis of salts in alcohols / non-water solvents?

elementcollector1 - 20-10-2012 at 21:05

What would be the electrolytic reactions for, say, pure isopropanol?
Is this a viable method towards electroplating or displacing some of the more reactive metals from their salts?

weiming1998 - 20-10-2012 at 23:04

Quote: Originally posted by elementcollector1  
What would be the electrolytic reactions for, say, pure isopropanol?
Is this a viable method towards electroplating or displacing some of the more reactive metals from their salts?


In non polar solvents, certainly not. They don't conduct electricity, and solutes dissolved in it isn't ionised. In protic solvents (like alcohol or water), no, because the solvent self-ionises into H+ and its conjugate base. The H+ competes with the reactive metal to be reduced as H2 at the cathode, yielding nothing but H2 gas.

In polar, aprotic solvents, possibly. In fact, electrolysis of LiCl in pyridine is a way of preparing lithium metal without doing a molten salt electrolysis.


[Edited on 21-10-2012 by weiming1998]

elementcollector1 - 21-10-2012 at 07:44

Does pyridine work for other metal chlorides, or just lithium?

blogfast25 - 21-10-2012 at 09:06

For hobbyists, electrolysis of salts in polar organic solvents is difficult to carry out. Both salts and solvents generally have to be bone dry and that's hard to achieve/maintain in a 'home' setting.

Pyridine also smells terribly. I remember carrying out an acid/base titration with it as solvent (at Uni) and getting just a bit on my fingers: horrible skunk like smell. And it ain't cheap either.

Here's a thread that gives some ideas about the difficulties:

http://www.sciencemadness.org/talk/viewthread.php?tid=1974