Sciencemadness Discussion Board

Sodium percarbonate

Chemgineer - 27-10-2025 at 15:39

I have too much sodium percarbonate that I don't know what to do with. Would it be reasonable to make a saturated solution in water and then cool it to 0 deg C to get as much of the sodium carbonate out of it and then have a fairly strong hydrogen peroxide?

Keras - 27-10-2025 at 22:44

This might seem tempting, but it’s ultimately bound to fail, or to give measly results. The solubility of sodium percarbonate is not very high at 20/25 °C, and any attempt to increase it by heating water will result in hydrogen peroxide faster decomposition to plain water. This is not a problem when you’re using it as a bleaching agent, because that’s what you seek, but if your goal is to get hydrogen peroxide, I think you’ll be better off buying a 12% solution and distilling it under reduced pressure, with the usual warning about peroxide handling.

Precipitating the carbonate out of solution will not increase hydrogen peroxide concentration anyway.

There are rumours of solvents able to 'leech out' the peroxide while leaving the carbonate untouched, but so far I've failed to put my hand on one.

Sir_Gawain - 28-10-2025 at 04:59

Diethyl ether should work, but a solution of pure peroxide in diethyl ether sounds a little suicidal.

Sodium percarbonate is less soluble in water than sodium carbonate so separation by crystallization won't work.

chempyre235 - 28-10-2025 at 05:38

You could always put some in with the laundry. It gets rid on stains very well. :P

On the other hand, there is a thread that goes into some ideas on this. I don't think anyone's had any successful experiments, so this is all theoretical.
https://www.sciencemadness.org/whisper/viewthread.php?tid=16...

bnull - 28-10-2025 at 06:35

Take a look at the sodium percarbonate article in the Encyclopedia of Reagents for Organic Synthesis (https://doi.org/10.1002/047084289X.rn00950).

Quote: Originally posted by Chemgineer  
Would it be reasonable to make a saturated solution in water and then cool it to 0 deg C to get as much of the sodium carbonate out of it and then have a fairly strong hydrogen peroxide?

No, for two reasons. First, hydrogen peroxide decomposes at high pH (which is above 10 for a strong sodium carbonate solution). Second, sodium carbonate will recrystallize as a perhydrate or, who knows, a mixed hydrate-perhydrate, if such thing exists.


Quote:
On the other hand, there is a thread

I remember that one. "Dissolve it in ethanol." I still don't know why I wrote that.

[Edited on 28-10-2025 by bnull]