al-Razi
Harmless
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Registered: 14-6-2019
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Potassium or sodium perooxide synthesis
Hello to everybody. I'm new in the forum.
I'm interested in the synthesis of sodium or potassium peroxides.
I'm thinking of thermally decomposing KNO3 with a 20 Amp welding machine.
The idea is to set up a pot (made of thick steel) and an iron rod connected to the welder and pour molten KNO3 in it.
The reaction would be: KNO3 -----> K20 + N2 + NOx.
I will later oxidise the potassium oxide with air to generate the peroxide.
Wikipedia says that heating KNO2 could cause an explosion. Given that it will be formed during the heating process, do you think it's an issue here?
Do you think it's a good idea?
Thank for sharing your ideas.
Next post will be about the syinthesis of sodium peroxide via thermal decomposition of the carbonate inside a tube connected to a calcium oxide pot
(in vacuum) to absorb the carbon dioxide.
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Keras
National Hazard
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Sodium peroxide might be easier to synthesise. Just look at the Wikipedia page dedicated to it…
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Prepic
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So I saw on the science madness wiki page it mentions that sodium ascorbate can decompose to Na2O at only ~ 220 °C! I've added the reference which
the wiki page states below.
I tried looking for the book and sadly couldnt find, also I some how doubt this reaction might even happen but perhaps someone else with experience /
more knowledge would be able to speak about this.
Decomposition of sodium ascorbate (potentially potassium ascorbate too) would be far easier and safer.
Reference:
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004.,
p. 310
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AJKOER
Radically Dubious
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Quote: Originally posted by Prepic  | So I saw on the science madness wiki page it mentions that sodium ascorbate can decompose to Na2O at only ~ 220 °C! I've added the reference which
the wiki page states below.
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Heating Lead ascorbate could produce PbO, but for more active metals, as the thermal decomposition of acetate in air produces CO2, I would expect what
happens practically is the decomposition forms Na2CO3. Heating the salt in a very thin layer under nitrogen gas, and excellent venting of exhaust
gases may allow some unreactive Na2O, but I'm still doubtful.
This is possibly a good example of the difference between a theoretical reaction, and what normally happens in a simple lab experiment (and not the
manufacturing of glass, see https://en.wikipedia.org/wiki/Sodium_oxide, where Na2O is usually made by employing sodium metal acting on NaOH or NaNO2).
On the SM Wiki page (see https://en.wikipedia.org/wiki/Sodium_oxide ), note the comment "The last three reactions give hot sodium oxide which can rapidly absorb moisture
and carbon dioxide and convert back to sodium hydroxide/carbonate. "
[Edited on 19-6-2019 by AJKOER]
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woelen
Super Administrator
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I agree with AJKOER. Any alkali salt of an organic acid, which contains oxygen, will lead to formation of Na2CO3 on strong heating. The other material
will be lost as CO2, H2O, CH4, C or other larger hydrocarbons in some rarer cases.
Making Na2O is quite difficult, even more difficult than making Na2O2. If you burn Na in air, you get mostly Na2O2 and only a minor amount of Na2O.
For this reason you hardly see any commercially available Na2O.
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