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Author: Subject: Preparation of cyanides
Magpie
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[*] posted on 25-2-2012 at 18:23


Quote: Originally posted by Magpie  
I would treat that black mass you took out of your fireplace with a lot of respect. Ie, there may be more cyanide there than you think. I suggest you test it using a Prussian Blue test as follows:

1.Place about 1 mL of water in a small test tube.
2. Add a smidgen (few mg) of FeSO4*7H20 or other soluble ferrous salt and stir until dissolved.
3. Acidify with a few drops of 1M HCl.
4. Add a smidgen of your product and stir.

An intense dark blue color indicates the presence of cyanide.

[Edited on 16-2-2012 by Magpie]


I should also point out that it is necessary for some ferric ions be present also. So I add a drop or two of 0.5M FeCl3 to be sure.

An interesting paper I found shows that the ideal pH for the formation of Prussian Blue is 5.5 to 6.5 and that the Fe:CN ratio of 0.5 is best:

http://www.saimm.co.za/Journal/v092n01p017.pdf

Brewster also says that the addition of a little fluoride ion keeps the Prussian Blue in suspension thereby providing the best coloration. I have 0.5M NaF handy for this, but usually don't need it.

Some procedures also call for heating the test tube. For inorganic work anyway I have found this not to be necessary.

What are your experiences/preferences?




The single most important condition for a successful synthesis is good mixing - Nicodem
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[*] posted on 26-2-2012 at 04:23


Finally!

Heated a pinch (may even less) of K. Ferrocyanide in a test tube. Once it became white, added excess of 88% phosphoric acid and heated the solution.

It started bubbling leaving water droplets at the side (also HCN?) and the solution turned blue suggesting the experiment was a success! The solution was not as blue as in myfanwy's experiment. Guess it's because the phosphoric acid was pure and colourless.

Sniffed the contents, but didn't get any bitter almond smell. Guess I am not genetically endowed. :(
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[*] posted on 26-2-2012 at 10:50


Quote: Originally posted by madmanhere  
Finally!

Heated a pinch (may even less) of K. Ferrocyanide in a test tube. Once it became white, added excess of 88% phosphoric acid and heated the solution.

It started bubbling leaving water droplets at the side (also HCN?) and the solution turned blue suggesting the experiment was a success! The solution was not as blue as in myfanwy's experiment. Guess it's because the phosphoric acid was pure and colourless.

Sniffed the contents, but didn't get any bitter almond smell. Guess I am not genetically endowed. :(
Ferrocyanide when acidified and heated releases HCN. You may or may not have converted the ferrocyanide to cyanide; you will obtain HCN in either case.

You actually sniffed it huh? There are bold chemists and old chemists, but there are no old, bold chemists.
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[*] posted on 26-2-2012 at 14:00


As I said the quantity was very small. Less than a pinch of ferro. And I didn't smell when the reaction was going on- only after removing the test tube from the flame.

It was too tempting. Other than that I was doing some pretty lame stuff- like heating NaOH crystals with H3PO4 and the likes. ;)

[Edited on 26-2-2012 by madmanhere]
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[*] posted on 26-2-2012 at 14:09


there is a german video on youtube where a guy heats potassium ferrocyanide and potassium carbonate in a test tube and cyanide forms on the side of the mass like a white beach. the test tube is angled at about 22.5 deg. so the cyanide will run away from the fused mass instead of mixing. i read that the cyanide actually forms on the bottom when done in an upright container.i would be tempted to sniff the dried product but not when its still warm and surely not when in gas form.
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[*] posted on 29-2-2012 at 17:11


Quote: Originally posted by RisingSun96815  
Today I replaced my thick-walled crucible with a steel soup can, and sure enough I got liquid. I let it cook for an hour, and had a black mass. So how exactly do I filter this to extract any KCN that is there?


I tried today morning with soup can.I added carbon as well.I saw liquid forming not enough to separate.And after an hour looks like it fused together to a molten mass.Does this mass has KCN ? If I add warm water to this ,will it dissolve Gold ?
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[*] posted on 29-2-2012 at 18:45


i doubt you will dissolve gold with all that charcoal still absorbing all the cyanide if you succeeded. i could not get the isolated white stuff to dissolve gold only copper but after i added peroxide too. silver just disintergrated into particles.why dont you crush the stuff and filter it?

[Edited on 1-3-2012 by cyanureeves]
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[*] posted on 29-2-2012 at 18:57


Quote: Originally posted by cyanureeves  
i doubt you will dissolve gold with all that charcoal still absorbing all the cyanide if you succeeded. i could not get the isolated white stuff to dissolve gold only copper but after i added peroxide too. silver just disintergrated into particles.why dont you crush the stuff and filter it?

[Edited on 1-3-2012 by cyanureeves]


You mean filter the way you mentioned with a precaution to prevent conversion to cyanate ?Its pretty tough to do so coz I m doing all these in my kitchen :P.I am thinking the 3 hour temp scheme (dont know how to establish it above a gas stove though) will melt it to liquid.Anyhow is this mass poisonous or would be harmless as ferrocyanide ?




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[*] posted on 29-2-2012 at 19:00


Did anyone try myfanwy94 ? Condensing HCN and neutralizing with NaOH ?

http://www.youtube.com/watch?v=K5NuqpdYDhE




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[*] posted on 29-2-2012 at 19:51


i havent tried condensing hcn. i got all the chemicals and glass and even bought two gas masks but i am really scared and havent mustered the guts yet. i think the charcoal canister russian mask will be best for this task. this summer i tried making nitric acid and all the nitric vapors leaked somewhere and never condensed.i cannot allow this to happen with hcn i got new kleck clips too. i will make nitric one more time then i will do the hcn.myfanwy did condense hcn but not with NaOH. honestly i think you need fire and a good blow dryer to get the heat up there.i believe you will get ferrocyanide if you start with ,potash and blood and iron shavings but it will stink your whole house and you need lots of heat.i used deer hooves instead of blood and did isolated the salt and did make prussian blue,i used a blue propane torch bottle i got from walmart

[Edited on 1-3-2012 by cyanureeves]
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[*] posted on 29-2-2012 at 20:21


Bad post.

[Edited on 1-3-2012 by madmanhere]

[Edited on 1-3-2012 by madmanhere]
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[*] posted on 29-2-2012 at 20:26


Quote: Originally posted by madmanhere  
Quote: Originally posted by cyanureeves  
myfanwy did condense hcn but not with NaOH.

I still don't understand how he got crystallized NaCN out of the solution. Any idea? The video shows him mixing NaOH with HCN and then the crystals without mentioning how he got it.

As kotze said, one could use cold ethanol under vacuum. But I don't know how to create the vacuum..

@explnfi:
Conducting the experiment in a kitchen? :o

[Edited on 1-3-2012 by madmanhere]


He used ethanol to precipitate it.




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[*] posted on 29-2-2012 at 20:31


Quote: Originally posted by cyanureeves  
i havent tried condensing hcn. i got all the chemicals and glass and even bought two gas masks but i am really scared and havent mustered the guts yet. i think the charcoal canister russian mask will be best for this task. this summer i tried making nitric acid and all the nitric vapors leaked somewhere and never condensed.i cannot allow this to happen with hcn i got new kleck clips too. i will make nitric one more time then i will do the hcn.myfanwy did condense hcn but not with NaOH. honestly i think you need fire and a good blow dryer to get the heat up there.i believe you will get ferrocyanide if you start with ,potash and blood and iron shavings but it will stink your whole house and you need lots of heat.i used deer hooves instead of blood and did isolated the salt and did make prussian blue,i used a blue propane torch bottle i got from walmart

[Edited on 1-3-2012 by cyanureeves]


What apparatus you plan to use ? Fractional Distillation Apparutus ? Then it should be safe right ?If I try,I will not use anything less than that.It comes with an affordable price in amazon / ebay (around $200) But I am willing to take a risk if I can make this mostly unavailable species of Chemical Kingdom.But your post is scary.How did the nitric vapors leak ?Which apparatus you used ?




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[*] posted on 29-2-2012 at 20:37


Quote: Originally posted by expInfi  
Quote: Originally posted by cyanureeves  
i doubt you will dissolve gold with all that charcoal still absorbing all the cyanide if you succeeded. i could not get the isolated white stuff to dissolve gold only copper but after i added peroxide too. silver just disintergrated into particles.why dont you crush the stuff and filter it?

[Edited on 1-3-2012 by cyanureeves]


You mean filter the way you mentioned with a precaution to prevent conversion to cyanate ?Its pretty tough to do so coz I m doing all these in my kitchen :P.I am thinking the 3 hour temp scheme (dont know how to establish it above a gas stove though) will melt it to liquid.Anyhow is this mass poisonous or would be harmless as ferrocyanide ?



About this molten mass , do you think it is poisonous ? Or it is ferrocyanide still ? Coz I could successfully clear everything without falling dead:) . Just wanted to know if I was playing with a ghost without knowing :)




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[*] posted on 1-3-2012 at 09:31


Quote: Originally posted by expInfi  
Did anyone try myfanwy94 ? Condensing HCN and neutralizing with NaOH ?

http://www.youtube.com/watch?v=K5NuqpdYDhE[/url]


Can someone tell me what specific hardware this guy used, and maybe include some links to on-line sources where they can be purchased? Also, I didn't see where NaOH came in, and the use of ethanol wasn't very detailed. Can someone go into more detail about these two processes? Thanks.
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[*] posted on 1-3-2012 at 10:53


Quote: Originally posted by RisingSun96815  

Can someone tell me what specific hardware this guy used, and maybe include some links to on-line sources where they can be purchased? Also, I didn't see where NaOH came in, and the use of ethanol wasn't very detailed. Can someone go into more detail about these two processes? Thanks.


NaOH was in the receiver flask.
HCN + NaOH -> NaCN + H2O
Ethanol is used to precipitate NaCN. I think the idea is to filter the salt after precipitation.
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[*] posted on 1-3-2012 at 15:21


Quote: Originally posted by RisingSun96815  
Quote: Originally posted by expInfi  
Did anyone try myfanwy94 ? Condensing HCN and neutralizing with NaOH ?

http://www.youtube.com/watch?v=K5NuqpdYDhE[/url]


Can someone tell me what specific hardware this guy used, and maybe include some links to on-line sources where they can be purchased? Also, I didn't see where NaOH came in, and the use of ethanol wasn't very detailed. Can someone go into more detail about these two processes? Thanks.


Its a distillation apparatus.It is not fractional ,but I think the safest would be to use the vacuum distillation apparatus.I ordered one from Amazon.I dont think air should be sucked up before it is boiled.But HCN can get into to you via skin.So a mask is a must and proper clothing as well. NaOH or KOH can be prepared by those flakes mixing with water(Experts : Correct me if I am wrong).Flakes are also available in ebay or amazon.I can see that he is using airtight receiver flask.But I would need someone here to say , if it is necessary to keep the vacuum in receiver to precipitate KCN using cold ethanol.




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[*] posted on 1-3-2012 at 17:18


i'll be darned myfanwy did use sodium hydroxide,i was about to do it without hydroxide.well i've done it with potassium hydroxide then because i did the same except i used too much hydroxide and i also used a tube and bubbled it directly into the mix.i'm sure it had condense hcn going into the mix but myfanwy's method is better because he used phosphoric acid and i used sulfuric.of course max was smarter and had precise temp control. my nitric distillation set up consists of a rb boiling flask.arm adaptor and a alhinn condensor going into an rb flask, all in 24/40. in my case ,having pro glassware did not make me a pro because my nitric did not condense,i dont know where it went all i got was mostly sulfuric acid.i need to learn more about securing the glassware.i'm used to using coffee pots and teflon tape.you know what they say"you can take the boy out of the ghetto,but what for?"i just made that up.
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[*] posted on 1-3-2012 at 17:22


Quote: Originally posted by cyanureeves  
i'll be darned myfanwy did use sodium hydroxide,i was about to do it without hydroxide.well i've done it with potassium hydroxide then because i did the same except i used too much hydroxide and i also used a tube and bubbled it directly into the mix.i'm sure it had condense hcn going into the mix but myfanwy's method is better because he used phosphoric acid and i used sulfuric.of course max was smarter and had precise temp control. my nitric distillation set up consists of a rb boiling flask.arm adaptor and a alhinn condensor going into an rb flask, all in 24/40. in my case ,having pro glassware did not make me a pro because my nitric did not condense,i dont know where it went all i got was mostly sulfuric acid.i need to learn more about securing the glassware.i'm used to using coffee pots and teflon tape.you know what they say"you can take the boy out of the ghetto,but what for?"i just made that up.


Well , I hope you wont use coffe pot to make HCN ! Would you think that vacuum distiller is a safe stuff to use ? And I am going to use KOH.
Could you pls answer , if vacuum is required to precipitate KCN using ethanol ?




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[*] posted on 1-3-2012 at 17:36


Quote: Originally posted by cyanureeves  
having pro glassware did not make me a pro because my nitric did not condense,i dont know where it went
Quote: Originally posted by expInfi  
Could you pls answer , if vacuum is required to precipitate KCN using ethanol ?
You kids are playing with fire, trying to make HCN without having a clue as to the basics of this kind of chemistry.

This is what happens when you think you can learn a complicated subject by watching lame youtube videos.

[Edited on 2-3-2012 by entropy51]
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[*] posted on 1-3-2012 at 17:40


Quote: Originally posted by entropy51  
Quote: Originally posted by cyanureeves  
having pro glassware did not make me a pro because my nitric did not condense,i dont know where it went
Quote: Originally posted by expInfi  
Could you pls answer , if vacuum is required to precipitate KCN using ethanol ?
You kids are playing with fire, trying to make HCN without having a clue as to the basics of this kind of chemistry.

This is what happens when you think you can learn a complicated subject by watching lame youtube videos.

[Edited on 2-3-2012 by entropy51]


It would have been better if you could convey the answer instead of giving a blanket warning.And pls do not judge that all are 5th grade failed.




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[*] posted on 1-3-2012 at 17:53


Quote: Originally posted by expInfi  
.And pls do not judge that all are 5th grade failed.
I see no evidence to the contrary.
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[*] posted on 1-3-2012 at 17:57


Quote: Originally posted by entropy51  
Quote: Originally posted by expInfi  
.And pls do not judge that all are 5th grade failed.
I see no evidence to the contrary.


Ok.Would you mind explaining how KCN can be prepared from the solution of condensed HCN in KOH ?




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[*] posted on 1-3-2012 at 17:58


And if possible precautions to be taken for the whole procedure ..



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[*] posted on 1-3-2012 at 17:59


What type of heat source is used in the video? Where can I buy one?

Is air pumped out of the apparatus using some type of vacuum?
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