Terran
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Help with carbon reduction of cyanate
So on the sciencemadness wiki I found the preparation for potassium cyanide, but this part confuses me, "One route involves melting cyanuric acid or
urea with potassium hydroxide. This gives potassium cyanate. Crush the resulting solid and grind it. Mix it with a reducing agent, such as carbon and
heat it until no more gases are released."
I've looked around but I cannot figure out how the carbon works in this reaction, or what it's for.
http://www.sciencemadness.org/smwiki/index.php/Potassium_cya...
Understand the theory before attempting the praxis.
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j_sum1
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KCN is similar to NaCN in synthesis and use.
The page you cited links to the page for NaCN.
http://www.sciencemadness.org/smwiki/index.php/Sodium_cyanid...
This has the answer to your question and a notable warning.
I would be hesitant about making cyanides myself and would not recommend it to anyone without a lot of experience and knowledge. The fact
that you are asking about a process as straightforward as carbon reduction raises warning flags. Just don't do it.
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Terran
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Thank you, I'm not planning to make any quite yet, I just have never come across carbon reduction before.
Understand the theory before attempting the praxis.
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XeonTheMGPony
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Quote: Originally posted by Terran  | | Thank you, I'm not planning to make any quite yet, I just have never come across carbon reduction before. |
It is used as a fuel in a great many reductions it is mainly used in metal industry. Most classical is gun powder
Learn it as it is vital for a great deal of things
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Tsjerk
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| Quote: Originally posted by XeonTheMGPony | | Quote: Originally posted by Terran | | Thank you, I'm not planning to make any quite yet, I just have never come across carbon reduction before. |
It is used as a fuel in a great many reductions it is mainly used in metal industry. Most classical is gun powder
Learn it as it is vital for a great deal of things |
I would call the production of iron the most classic  about 3200 years old.
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PirateDocBrown
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Much easier to make KCN from laundry bluing.
Heat the bluing gently, to drive off the water.
When it's dry, it's essentially Fe7(CN)18.
Add KOH, and raise the temp to a melt.
Hold, excluding air, for a couple of hours for the reaction to finish.
Dissolve in anhydrous EtOH. Neither unreacted Prussian Blue nor iron oxides/hydroxides are soluble in it, but KCN is.
Separate from unreacted KOH via recrystallization.
All OTC, lower temps, nothing in (insanely toxic) gas phase, easy separation.
https://www.amazon.com/Mrs-Stewarts-Bluing-1101-MPLS-8oz/dp/...
[Edited on 12/18/19 by PirateDocBrown]
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Tsjerk
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How do you suggest doing the recrystallization?
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Dan Vizine
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The KOH/KCN separation is sure not going to be a walk in the park. It probably has a definite learning curve.
I think it's a matter of first extracting the pulverized reaction mass with boiling, fairly anhydrous EtOH. You then clarify by filtration and
concentrate the solution to incipient crystallization. Just getting sufficiently dry alcohol might be quite difficult.
On the other hand, this is the same exact type of horrible separation that the cyanate route suffers from it its final stages. Just horrible.
I'd go by the pyrolytic route. The cyanate route is really just an industrial process that is ill-suited for home synthesis.
[Edited on 12/19/2019 by Dan Vizine]
"All Your Children Are Poor Unfortunate Victims of Lies You Believe, a Plague Upon Your Ignorance that Keeps the Youth from the Truth They
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PirateDocBrown
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KOH is far more soluble in cold EtOH than KCN.
Dissolve the mix in a minimum of boiling EtOH, then chill.
The crystals formed will be much purer than you started, assuming you have excluded atmospheric contamination (Basically, O2 to react to KOCN, and CO2
to react KOH to KHCO3).
I'd do the recrystallization at least twice.
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chemplayer...
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We tried the cyanate reduction (it's in one of the videos) and the results were pretty terrible. You can determine via a prussian blue test that there
is cyanide in the product, but a low uncertain concentration.
Ultimately the only method we tried that produced cyanide salts pure enough for synthetic purposes (e.g. to prepare mandelic or malonic acid) was the
reaction of anhydrous potassium ferrocyanide powder with sodium metal.
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