Romain
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Oxone® triple salt: Separation into its components?, Reaction with copper?
Hi,
I recently bought some oxone. It is a free-flowing white powder sold as "Oxygène Actif" (which probably translates to "Active Oxygen") used to
disinfect swimming pools. My bottle says it contains 1000 mg/kg of "Potassium Bis(peroxymonosulfate)bis(sulfate)" and there is a corrosive label.
After a quick google search, I found out it's a triple salt of potassium peroxymonosulfate, potassium bisulfate and potassium sulfate:
2KHSO5·KHSO4·K2SO4.
So my question is: Is it possible to separate the Oxone into it's components? I was thinking of using fractional crystallization but since a triple
salt is formed through crystallization of 3 salts in the same crystal lattice, I guess it won't work. What would you suggest?
I was also wondering if you could etch copper with KHSO5? I'm currently away from my lab so I don't have any copper to test for a reaction.
I do however have a zinc-plated steel paper staple and a soda can aluminium "pop tab".
I dissolved a teaspoon of oxone into about 50 ml of water: bubbles are evolved (presumably oxygen gas). I immersed the staple and the pop tab in the
solution and very few bubbles slowly appeared. The staple turned dark brown. After some time, the solution turned faint orange-brown around the
staple, indicating that iron reacts with oxone to form some iron(III) compound. If that's true, then copper probably reacts too, since iron(III)
chloride is used to etch copper. What do you think?
Sources:
The wikipedia page about KHSO5
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12AX7
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Is there a KHSO5.K2SO4, K2SO5.KHSO4 or K2SO5.K2SO4 (i.e., one or the other monobasic, or both fully ionized) double salt in the system as well? If
not, it might help to add some K2CO3 (or KHCO3 or KOH or whatever) to neutralize one or both monobasic anions and force it into crystallizing as
something else.
For etching, it's probably not bad as is. More acid may help (if the solution seems to be slowing down or leaving chalky deposits, add some
sulfuric). KHSO5, or something along those lines, is frequently used for this purpose.
Aluminum won't corrode in a sulfate solution; try adding a few grains of CuCl2 near the aluminum surface, this should catalyze things. Beware, if it
takes off properly, it will be rather... vigorous.
Tim
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woelen
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The free salt K2SO5 or KHSO5 is very unstable and cannot be kept around for any length of time. I also purchased this triple salt and this is the
common form in which it appears. It is the only stable form which (when kept perfectly dry) can be kept around for a very long time. This material is
not hygroscopic and keeps indeed very well. So, I would keep it as is.
In the wet state, the material very quickly looses its oxidizing power. A solution just becomes an acid solution (potassium hydrogen sulfate) after a
day or so.
Keep in mind that double salts and triple salts are not simply mixtures. They really are chemical compounds with a well-established and precisely
determined stoichiometry. So, you bought a pure compound. And the name of this compound is "oxone". The wiki page about KHSO5 is wrong in my opinion,
calling KHSO5 "oxone".
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Romain
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Thanks for the infos!
About the bubbles on the aluminium surface: I think it's because the surface of the aluminium creates nucleation points for the oxygen to bubble out
of solution. Just like when you put a carbonated drink in a dirty glass.
I'll try to etch a PCB, hopefully it'll work.
Also have you ever heard or made Oxone flash powder? I'd be interested to know if it would work.
In any case I also read it's a useful oxidant in organic synthesis so I may aswell use it this way.
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Romain
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I just found DuPont's technical datasheet for their product Oxone. They say peroxymonosulfate is the active anion when Oxone is dissolved and they also give an
idea of it's oxidizing power.
Peroximonosulfate can:
Oxidize halides to halogens (tested with chloride, I guess it works for bromide and iodide though I don't have any of these)
Oxidize copper metal to Cu2+ (So etching copper WILL work)
Oxidize Fe2+ to Fe3+ (tested with an iron staple)
Interesting info anyway...
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