halogen
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Route to K2O and Na2O?
What of the possibility of Heating KCO3 or NaHCO3 to form K2O or Na2O. At what temprature would this occur and is it feasible (That is is it easier to
just buy it?)
F. de Lalande and M. Prud'homme showed that a mixture of boric oxide and sodium chloride is decomposed in a stream of dry air or oxygen at a red heat
with the evolution of chlorine.
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neutrino
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It would probably just be easier to buy it. To do this with calcium carbonate, as a comparison, requires prolonged and very high temperatures. It
might be feasible on a microscale, but nothing larger.
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12AX7
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Lot easier to calcine lime or magnesia (just a few hours at yellow heat, easy enough for someone with a pottery kiln) then precipitate the carbonate.
I don't know if alkali carbonates will release it at all.
If you want raw oxides, you'll need to dehydrate the material further, I don't know if that happens at any temperature.
Tim
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BromicAcid
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It would be incredibly energey intensive to try and preform this conversion. Potassium oxide is incredibly prone to oxidation even from atmospheric
oxygen. One possibility would be to mix concentrated KOH with concentrated H<sub>2</sub>O<sub>2</sub> to precipitate
potassium peroxide hydrate and heat this in a stream of dry air which would give mostly potassium superoxide and some peroxide then heating this under
vacuum to take away the oxygen, under these conditions though oxygen is first lost to leave the peroxide then this decomposes some to potassium metal,
some to potassium superoxide and some to potassium oxide.
Note:
Potassium peroxide is oxidized to potassium superoxide by oxygen gas even in liquid ammonia.
The following reaction is prevelent at 450C in vaccum:
2K2O ---> K2O2 + 2K(gas)
[Edited on 6/17/2005 by BromicAcid]
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garage chemist
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Zinc powder reduces NaOH to Na2O:
2NaOH + Zn --(heat)--> Na2O + ZnO + H2
We did this reaction in school to prove that the product of the reaction of sodium with water was not sodium oxide.
The produced hydrogen was ignited and therefore shown to be contained in the educt.
[Edited on 17-6-2005 by garage chemist]
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Scratch-
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http://en.wikipedia.org/wiki/Calcination
http://en.wikipedia.org/wiki/Quicklime
http://en.wikipedia.org/wiki/Limekiln
You might be able to do something similar with sodium and potassium carbonates. Although I seem to remember they have a higher decomposition
temperature.
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halogen
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| Quote: |
One possibility would be to mix concentrated KOH with concentrated H2O2 to precipitate potassium peroxide hydrate and heat this in a stream of dry air
which would give mostly potassium superoxide and some peroxide then heating this under vacuum to take away the oxygen, under these conditions though
oxygen is first lost to leave the peroxide then this decomposes some to potassium metal, some to potassium superoxide and some to potassium oxide.
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What concentrations would be suggested?
F. de Lalande and M. Prud'homme showed that a mixture of boric oxide and sodium chloride is decomposed in a stream of dry air or oxygen at a red heat
with the evolution of chlorine.
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BromicAcid
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As concentrated as you can muster, remember that the reagents need to be mixed at ~0C due to basified
H<sub>2</sub>O<sub>2</sub> being unstable at room temp. The octahydrate of sodium peroxide being formed and the dihydrate of
potassium peroxide being formed.
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