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Author: Subject: Sodium Permanganate
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[*] posted on 9-9-2018 at 20:46
Sodium Permanganate


I can't get my hands on potassium permanganate, so I figured that I would make sodium permanganate from sodium hydroxide and manganese dioxide. My method will be to add manganese dioxide to sodium hydroxide and bubbling oxygen through
it.

The reaction is
4MnO2+4NaOH+3O2—>2H2O+4NaMnO4

Just wanted to try it out and compare it to NurdRages KMnO4 method and see how feasible it is.




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[*] posted on 9-9-2018 at 20:54


Well I don't think that would work in aqueous solution.
How would you bubble O2 into the solution? fishtank bubblers? How would you remove CO2 from air?




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[*] posted on 9-9-2018 at 21:19


This will simply not work even if you melt the reagents. In order to achieve a decent yield of manganate, industry uses precise temperature and pressure control. The exact temperatures, pressures and concentrations of oxygen in the gas stream pumped through the melt are trade secrets.

Also NaOH doesn't work at all here. The oxidation stops at manganate (V) which is so unstable that it decomposes by the time the melt solidifies.

Nurdrage didn't really make permanganate in those videos. His extraction washes were just purple, but even a 0.01M solution of KMnO4 is almost black.





[Edited on 10-9-2018 by CobaltChloride]
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[*] posted on 9-9-2018 at 21:25


I think I might try it on a small scale just in case. Im bubbling pure oxygen through it with a bubbler and H2O2 and MnO2




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[*] posted on 10-9-2018 at 00:00


Well, this should work (somewhat) if molten reagents are used, but workup of the permanganate will be hard. In aqueous solution it will not work.

In the melt of NaOH and MnO2 you get manganate(VI), a dark green compound. This can be dissolved in water and when the solution is made neutral (or weakly acidic), then the green manganate disproportionates to MnO2 and permanganate. The MnO2 must be allowed to settle and then by addition of a potassium salt (e.g. K2CO3) you might be able to get some crystals of KMnO4. Getting pure material, however, will be hard and assessing the purity of your product also will be very hard, due to the very very dark color of the solution of KMnO4.




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[*] posted on 10-9-2018 at 01:18


Quote: Originally posted by CobaltChloride  
Also NaOH doesn't work at all here. The oxidation stops at manganate (V) which is so unstable that it decomposes by the time the melt solidifies.
Where do you get such info? I've never heard of this before.



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[*] posted on 10-9-2018 at 01:28


The specific info I presented there is in part from Nurdrage's video on making KMnO4 where he says that sodium salts will not work and also from the document I attached.

"The price of sodium permanganate is about 5 to 8 times that of KMnO4. This is mainly due to the fact that NaMnO4 cannot be made in the same way as KMnO4, because the oxidation of MnO2 in a NaOH melt does not lead to the required Na2MnO4 (with hexavalent Mn) but only to Na3MnO4 with pentavalent Mn"

Attachment: reidies2000.pdf (560kB)
This file has been downloaded 278 times

[Edited on 10-9-2018 by CobaltChloride]
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[*] posted on 10-9-2018 at 03:24


I do not think it makes a big difference in the melt's behavior. With sodium ions you get oxidation to the +6 state as well.

The reason of the high price of NaMnO4 is that it is much more difficult to purify than KMnO4. KMnO4 only is sparingly soluble in cold water and easily forms crystals. NaMnO4 is extremely soluble in water and even in highly concentrated solution it does not form crystals. Getting this compound in a pure dry state is very difficult and as long as it is wet, it is not stable on storage (slow release of O2, solution becomes alkaline, and hydrous MnO2 is formed). With all of these issues it is easy to understand why NaMnO4 is so expensive.




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[*] posted on 10-9-2018 at 05:56


While the method you proposed isn't going to work at all, you could try reacting MnO2 with an aqueous solution of NaOH while using NaOCl as the oxidizer. The sodium hypochlorite that is sold as bleach is about 6% NaOCl, so you will have to make a small scale synthesis.
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[*] posted on 10-9-2018 at 06:21


That method isn't very good as illustrated in another thread (https://www.sciencemadness.org/whisper/viewthread.php?tid=84...). Firstly, you have to use potassium salts if you want to recover any solid permanganate (as woelen also said). Secondly, this means that you also get KClO3 as a side product and this is very hard to separate from KMnO4. The only good way of making KMnO4 at home is by the catalyzed persulfate oxidation using Na2S2O8 specifically.

@woelen, what you are saying sounds plausible. The document might be wrong. Let's see what are the results of Abromination's experiment.

[Edited on 10-9-2018 by CobaltChloride]
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[*] posted on 10-9-2018 at 07:52


At this point, I might just do this as an experiment instead of a plausible synthesis. My variable might be concentration of hypochlorite, control would be attempting in an aqueous solution instead of a solution of sodium hypochlorite.



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[*] posted on 10-9-2018 at 18:39


Does anyone know a better way to open a AA battery? I broke the number one rule and tryed to open it with dull pipe cutters and it vented its electrolyte all over my crotch.



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[*] posted on 10-9-2018 at 22:02


I wouldn't suggest using a AA battery. Get the cheapest and biggest battery you can find. Those contain just the very impure MnO2, a Zn casing and a graphite rod. They don't contain any liquid electrolyte.

I usually just peel off the steel casing from this using pliers and then I can extract what's inside.

[Edited on 11-9-2018 by CobaltChloride]
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[*] posted on 11-9-2018 at 17:12


Quote: Originally posted by CobaltChloride  
I wouldn't suggest using a AA battery. Get the cheapest and biggest battery you can find. Those contain just the very impure MnO2, a Zn casing and a graphite rod. They don't contain any liquid electrolyte.

I usually just peel off the steel casing from this using pliers and then I can extract what's inside.

[Edited on 11-9-2018 by CobaltChloride]


Would D or C batteries work?




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[*] posted on 11-9-2018 at 17:25


Quote: Originally posted by CobaltChloride  
I wouldn't suggest using a AA battery. Get the cheapest and biggest battery you can find. Those contain just the very impure MnO2, a Zn casing and a graphite rod. They don't contain any liquid electrolyte.

I usually just peel off the steel casing from this using pliers and then I can extract what's inside.

[Edited on 11-9-2018 by CobaltChloride]
I would only go for used batteries as the new ones can be used to power things. Using new ones just for the chemicals inside isn't worth the $. Also the MnO2 in alkaline ones are purer than Zn/C ones. If possible I'd also choose pottery grade over battery grade. The former doesn't need the hassle of opening the batts and removing the C impurity from MnO2.



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[*] posted on 11-9-2018 at 18:12


Quote: Originally posted by fusso  
Quote: Originally posted by CobaltChloride  
I wouldn't suggest using a AA battery. Get the cheapest and biggest battery you can find. Those contain just the very impure MnO2, a Zn casing and a graphite rod. They don't contain any liquid electrolyte.

I usually just peel off the steel casing from this using pliers and then I can extract what's inside.

[Edited on 11-9-2018 by CobaltChloride]
I would only go for used batteries as the new ones can be used to power things. Using new ones just for the chemicals inside isn't worth the $. Also the MnO2 in alkaline ones are purer than Zn/C ones. If possible I'd also choose pottery grade over battery grade. The former doesn't need the hassle of opening the batts and removing the C impurity from MnO2.

Im not going for purity though, I just want to see if the reaction is possible.




List of materials made by ScienceMadness.org users:
https://docs.google.com/spreadsheets/d/1nmJ8uq-h4IkXPxD5svnT...
--------------------------------
Elements Collected: H, Li, B, C, N, O, Mg, Al, Si, P, S, Fe, Ni, Cu, Zn, Ag, I, Au, Pb, Bi, Am
Last Acquired: B
Next: Na
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