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12AX7
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A 5% excess of NaOH should get the pH in the 13 range, which should be good enough to keep HCN gas down. Don't know about hydrolysis, it can't be too
bad...but maybe it can.
I would try to get it in crystalline form, being careful about heat and atmospheric CO2 and H2O decomposing it to HCN and NaOH. Once solid, it should
be pretty stable, although it may still be prone to decomposition.
It would be a lot nicer if HCN were more acidic and had a much lower odor threshold than its lethal dose...
Tim
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Antwain
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Yeah, cyanide is the most poisonous thing I have ever attempted. But safety first - the minimum quoted minimum lethal dose corresponds to 160mg (for
me) so I have some idea of how much that is in real terms. Not that I want to try taking 80mg.
Also, I forgot to post after my experiment... I was expecting a yield of ~70g theoretical. what I now have is a slurry in some ethanol which is ~25g
and is probably only <5g of something (white powder), and 700mL of 80% ethanol solution with god only knows what in it. Sodium cyanide is quoted as
being 'slightly soluble in ethanol' by merck and other sources, but is soluble in water 1:1@0*C, 2:1@100*C. Also sodium formate is 'almost insoluble
in ethanol' and sodium hydroxide dissolves 1g in 7.2mL ethanol. Also given that the solution I had poured like conc. NaOH, ie. like honey, I wonder if
maybe I never made much cyanide. A lot of gas bubbled through the solution (possibly because the base was too concentrated and it clogged) but I had a
bleach soaked cotton ball in the release tube and a fan blowing into the shed.
Can anyone tell me if the concentration of the distillation mixture should be strong or weak? And does anyone know a good method for ensuring good
contact between a gas/liquid interface. Also, I am thinking of using KOH (lab grade) next time, so if i dissolve this in ethanol so that the cyanide
will precipitate out (1-3g per 100g ethanol solubility) is this going to help, or should I stick with aqueous solutions?
I have NO experience with practical gas chemistry so any help would be useful.
PS. I am currently thinking of using an upturned funnel, which is a pain because of the diameter of the beaker or whatever required + I can think of a
bunch of ways in which this could fail and release HCN, or bubbling it through a long thin coloumn, of which I have none.
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kmno4
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NaCN can be made in the same way as KCN, from K4[Fe....] and H2SO4/H3PO4. Diffrence is that NaCN crystallises as hydrate ( NaCNx0,5H2O or x1H2O) from
EtOH so H2O must be quickly evaporated or hydrate should be kept at lower (<10 C) temperature. But it is much easier filter off NaCN than KCN,
because of its much larger crystalls. It has also lower molar mass: 49g NaCN corresponds 65g KCN and there are less problems with stirring/filtering
suspentions.
Generally, cyanides should not be kept/heated for a long time in strongly alkaline solutions - they decompose to brown products (propably polymeric
CxNy ).
BTW.
Carl Scheele (discoverer of HCN and many others chemicals...) described smell and taste of HCN, ha ! It was hard man, almost dead
because of Cl2... Great oldschool chemist 
On the picture: about 60g NaCN (two runs). One run takes about 4-5 hours (from starting distilation to placing dry NaCN in a jar)
Everything can be done....
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JohnWW
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| Quote: | Originally posted by kmno4(cut)
Generally, cyanides should not be kept/heated for a long time in strongly alkaline solutions - they decompose to brown products (propably polymeric
CxNy ). |
That would be (CN)x, polycyanogen, for which cyanides would firstly have to be hydrolysed to cyanogen, (CN)2. If a form of it exists as a long-chain
linear molecule, amorphous and like a plastic, its formulation would be probably:
=N(+)=C(-)-N=C=N(+)=C(-)-N=C=N(+)=C(-)- etc.,
with the N atoms being alternately in the (V) and (III) oxidation states, and carbanion Cs bonded to quaternary ammonium Ns. This would be
electrically conducting due to resonance delocalization of the electrons, resulting in the double and single bonds alternating in position, like
graphite and polyacetylene and the electrically conducting plastics developed in recent years especially by Prof. Alan MacDiarmid (from New Zealand),
and, similarly, likely to absorb all wavelengths of visible light. Two- and 3-dimensional polymeric structures may also be possible, but may not be
electrically-conducting, or else may conduct electricity only in one direction.
With such an unsaturated structure, it is likely to react fairly readily with halogens and oxidants, and possibly sulfure, which has been reported.
I obtained 34 results for "polycyanogen" on Google, some of which are as follows.
This patent describes the electrochemical polymerization of cyanogen in solution, to give a polymer with a molecular weight over 500: http://www.freepatentsonline.com/4649038.html
According to http://doi.wiley.com/10.1002/pola.1993.080311020 (password-protected) and http://cat.inist.fr/?aModele=afficheN&cpsidt=8786062 it can be made by the reaction of KCN and ICN.
http://www.springerlink.com/index/P772VQ47H3552500.pdf and http://doi.wiley.com/10.1002/pola.1988.080260915 and http://linkinghub.elsevier.com/retrieve/pii/S004060900300304... and http://www.turpion.org/php/full/infoFT.phtml?journal_id=rc&a... (all password-protected) and http://www-g.eng.cam.ac.uk/edm/Publications/pdf/Rodil_TSF200... and http://202.127.1.11/surface%20science/517/51725.pdf describe its electrical
conductivity and optical properties, as well as preparation.
This article (password-protected) describes a cross-linked 2-dimensional polymer: http://dx.doi.org/10.1002/chem.200501528
This article describes its possible use in photovoltaic cells, especially cross-linked with sulfur: http://www.phy-astr.gsu.edu/hastings/Publications/SYnthetic%...
If anyone has access to the password-restricted articles mentioned above, it would help if you can download them and piost them here, please. I am
especially interested in the electrical conductivity angle and the possibility of photovoltaic cells.
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kmno4
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You should have looked for "paracyanogen".
A lot of articles, for example:
J. CHEM. SOC. FARADAY TRANS., 1994, 90(2), 327-332
Structural Studies on Paracyanogen and Paraisocyanogen
Attachment: JCHEMSOC.pdf (221kB)
This file has been downloaded 1562 times
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JohnWW
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Thanks. I saw some mentions of paracyanogen in the search for "polycyanogen"; but the two appear to be two quite different polymeric substances.
Paracyanogen consists of infinite chains, not of alternating C and N atoms as above, but of 6-membered rings (like tetracene, pentacene, etc.)
consisting of alternating C and N atoms, and is a semiconductor due to resonance delocalization of electrons in alternating single and double C-N
bonds, although probably not as conducting as polycyanogen.
BTW cyanogen has a much less stable isomer, isocyanogen, CN-CN, which similarly polymerizes to a solid compound, paraisocyanogen, which is a
non-c0nductor
[Edited on 2-8-07 by JohnWW]
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kmno4
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Searching on RSC site gives 0 (zero) articles with word "polycyanogen", ACS gives 2 articles. Compare to searching with "paracyanogen".
Searching "PbNO3" in Google also gives results..... 
Formation of polycyanogen in the solid phase reaction of cyanogen iodide and potassium cyanide
Inorganica Chimica Acta, Volume 113, Issue 1, 3 March 1986, Pages 67-70
Z. Tóth, J. Gulyás and M. T. Beck ----> 'References' section
[Edited on 3-8-2007 by kmno4]
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Antwain
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kmo4, could you describe briefly the procedure you used, especially with regard to heating method (water bath, oil bath etc), endpoint, and workup (so
you evaporated down an aqueous solution, and then precipitated it... is that right). Thanks heaps
I have seen references to polymers, specifically the tetramer of HCN, however the hydrolysis is described in multiple older books as being to ammonia
+ formate, or ammonium formate. I would put my money on this being a neutral/acid hydrolysis (ie HCN is a weak acid), although I cannot back this up
with literature.
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Antwain
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And a word of warning (this was a pretty stupid mistake) 
DON'T put alkaline solutions in PET bottles. Fortunately my shed floor is pavers so the solution mostly drained away, but I had to deal with several
grams of what was probably sodium cyanide. And the plant next to that side of the shed died.
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Elawr
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It would probably be a good idea to keep some thiosulfate (hypo) on hand in case you inadvertently were to absorb enough CN- to make you sick. We
keep it as the sodium salt to give IV for CN- poisoning. Works orally too. The thiosulfate ion in in vivo is a substrate for hepatic rhodanase
enzymes which convert CN- to the much less toxic SCN- , which is excreted into the urine. Thiosulfate works prophylactically as well, animal studies
have shown an increase in LD50 several-fold with thiosulfate on board. If one were to ingest some hypo prior to working with cyanides, then the urine
could be easily checked qualitatively for SCN- by using Fe salts to form bright colored complexes. I do not know what the threshold is - whether or
not it would pick up trace exposures too small to cause any symptoms.
At least cyanide is not cumulative. If it doesn't kill you outright you'll likely survive, although neurological trauma from cellular anoxia might be
permanent!!!
[Edited on 6-8-2007 by Elawr]
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12AX7
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Remember, the average healthy person has three times excess oxygen capacity in the blood (the excess is for athletic activity, of course). Sitting or
laying doing very little doesn't consume much oxygen. So, you might figure the maximum dose is roughly the amount that inactivates 2/3 of the blood's
active hemoglobin.
Tim
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Antwain
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actually, a much better antidote is amyl/butyl nitrite, which oxidises hemoglobin to met-hemoglobin (FeII to FeIII). Since we have that in plentiful
supply it doesn't matter about the loss of the a bit of hemoglobin. This competes heavily with cytochrome a3, which we don't have much of, and is
ESSENTIAL to the respiration process. Believe me, I had a test concerning this less than 2 months ago. The FeIII is much more susceptible to CN- than
FeII due to the more polarising nature of the ion, and the charge carried by the cyanide. Sitting still and doing nothing will not help as much as you
might think, although you probably shouldn't exercise just after you have been poisoned
Conversely, carbon monoxide, being a softer and uncharged base prefers the less polarising FeII, and will preferentially attack FeII in the body.
Sitting still after carbon monoxide poisoning will help a great deal since only the 'carrying capacity' has been effected, whereas with cyanide the
respiration process is effected, and once the cyanide has actually poisoned you (as opposed to merely been ingested or whatever) you are pretty well
stuffed.
Thanks for the concern but I am being very careful, to the point of hindering my experiments, and for once in my life actually know what I am doing
:>
btw, another old school method of dealing with poisoning involved egg white, but only for ingestion.
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Antwain
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Well I did it, kind of.
Theoretical reactions;
K4[Fe(CN)6] + 5H2SO4 ----> 4KHSO4 + FeSO4 + 6HCN
HCN + KOH ------> KCN + H2O
A distillation setup was put together consisting of a 1L RBF at the distilling end, a B24 water condenser (30cm) and a 500mL RBF for collection of the
distillate. A short length of hose was placed on the end of the condenser tube, so that it sat around a centimeter above the magnetic stirrer in the
receiving flask. K4[Fe(CN)6] (105.6g, 0.25mol) was placed in the 1L RBF and dissolved in water (200mL) with stirring and heat. KOH (84.2g, 1.51mol)
was placed in the receiving flask and dissolved in water (200mL) with stirring. H2SO4 (100mL, 1.87mol, 49% excess) was mixed with water (200mL), and
this was added to a dropping funnel on the distillation beaker, topping up as required.
After heating the ferrocyanide solution to reflux, the the sulfuric acid was added slowly of the course of ~1/2 hr. As soon as the acid started
entering the flask bubbling occurred and the solution boiled. The solution began to change colour at the top to apple green. After the addition of all
the acid, the entire solution had become apple green and the receiving flask had developed a slight yellow tint. It was also necessary to relieve the
pressure several times to prevent the distillate from being sucked back up the condenser. The temperature of the vapor distilling over was not
constant but stayed mostly at ~85*C for a while and then rose to 97*C.
Additional H2SO4 (20mL, 0.37mol) mixed with water (40mL) was added, and further boiling occurred, but the temperature of the vapor did not change nor
did the appearance of the distillation solution. The flasks were cooled, and the green solution placed in a waste bottle. After rinsing the 1L flask
and distillation setup, the placing of the flasks was reversed to as to distill out of the 500mL flask.
This solution was distilled until about 100mL remained, at which time the 500mL flask was disconnected while still quite warm. A VERY strong smell of
ammonia was present. The solution was cooled in an ice bath, but simply gelled, so it was added to a larger beaker and ~350mL of ethanol added. This
was filtered, which removed all but about 50mL of liquid. The gelatinous white powder was placed between two filter papers with many sheets of paper
towel on either side, and a brick placed on top. After half an hour the filter parers, which were only damp, were placed on a warm heating mantle for
around ~1/2hr. After this time the white powder was dry and was placed in a bottle (yield 33.3g, 0.51mol, 34%), however it had attacked the steel top
of the heating mantle, leaving a ring of ferrocyanide on the filter paper.
So in conclusion, I got a pretty crappy yield, of probably not entirely the right stuff (it felt and smelt like sodium acetate does when heated, which
is a worry because formate is one of the decomposition products) but there is definitely cyanide there as evidenced by it attacking my mantle. The
ammoniacal smell stopped after the addition of alcohol so if I do this again (I have enough ferro for one more attempt) I will be making a solution of
KOH in ethanol, and the KCN can precipitate out.
Also, does anyone know any good tests for cyanide. Ideally a volumetric quantitative one... I only have 0.1G accuracy and dont want to use all of my
cyanide to get an assay. Perhaps a colourimetric one where I run something into a solution of 5.0g of white powder and eventually it changes colour. I
can do volumes fairly well if they are not too small. It would be really good to know how much of my 'cyanide' is cyanide
[Edited on 12-8-2007 by Antwain]
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thelittlestknife
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This sounds a lot like the successful attempt above, but I had a few questions...
Ok. So I recently found an interesting recipe called the Bucher Process, which is probably old hat to a lot of the posters on this thread, but I was
curious to test it out. Unfortunately the highest training I have in Chemistry is 11th grade(and even that wasn't too good), so I'll do my best to
follow.
The Bucher Process (for those who don't know) is producing NaCN from Sodium Carbonate, Carbon and Nitrogen (just good ol' air) and Iron filings as a
catalyst.
The Sodium Carbonate can be produced evidently by heating up Sodium Bicarbonate (Baking Soda) above 270 *C and I've found a chemistry website that I
can obtain lab quality Graphite and Iron Filings. A yield of 5 grams of NaCN requires 5.41 grams of Sodium Carbonate (Na2CO3), 2.45 grams of Graphite
(Carbon) and 4 grams of Iron Filings (Fe)
My questions regarding this process:
1. What materials will I need? I'm assuming a hot plate that can reach 270 *C and over. Perhaps a crucible for mixing the ingredients and placing on
the hot plate for heating, or is there a better vessel? Tongues as not to get burned.
2. How will I know the Sodium Bicarbonate has successfully changed to Sodium Carbonate after heating? How long should I leave the baking soda over
heat?
3. When heating the mixture, should I put all of the ingredients in together and then heat, or should I add ingredients intermittently in some precise
order?
4. What temperature should I use for the mixture? Will I know when the process is complete?
5. Do I need to use something so separate the NaCN from the remaining Iron Filings?
Any help in this matter would be greatly appreciated.
Thanks!
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Eclectic
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Would you also like lessons in how to fly a plane but not land it?
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thelittlestknife
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Sure, anything to get me off the ground.
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Antwain
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I looked into the Bucher process before deciding how to try to make cyanide. After looking closely at it, I couldn't rationalise it actually working
on a small scale, in an oxygen atmosphere, however there are ppl on the internet who claim it has worked. If you do decide to try it you will need a
large excess of carbon, which will burn in the oxygen which comes free with every 4 parts of nitrogen in our air. Also, the equilibrium to form
cyanide requires carbon monoxide to be removed from the vicinity... not easy when your excess carbon is going to be reacting with oxygen producing
this. Finally, despites ppls claims, I think it would be much more likely to work with anhydrous potassium carbonate... at the temperatures required
for the reaction, the sodium ferrocyanide (an intermediate) tends to want to break down to form nitrogen and carbon, while potassium ferrocyanide is
stable to ~600*C
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Filemon
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| Quote: | Originally posted by DDTea
Well, the reaction between Chloroform and Ammonia is a well-known way to produce Hydrogen Cyanide...
NH3 + CHCl3 --> HCN + 3 HCl
If you don't mind working with straight HCN, then this seems like a feasible route. At least, it would be for me, since I have fairly easy access to
Ammonia Gas and Chloroform...
The only trouble would be separating the HCl. |
How the process it is? Do work if it chloroform and ammonia (ac)?
[Edited on 5-9-2007 by Filemon]
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Filemon
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| Quote: | Originally posted by madscientist
[HCOO-][NH4+] --} HCONH2 + H2O
HCONH2 + H2O --} HCN + 2(H2O)
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Where you have read that? I have never read that the formamide decompose HCN for heat. Have not you made a mistaked with the dehydration with P2O5?
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S.C. Wack
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There are numerous patents on this. It is not for amateurs.
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Filemon
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I have read that the reaction of an amide with NaBrO produces nitrile.
http://www.ugr.es/~quiored/qog/grup_fun/amidas.htm
With this reaction one could make with formamide NaCN. Does somebody know this reaction? For that one cannot make with NaClO?
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amchem2000
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NH3(aq) + CHCl3 => HCN + 3HCl
- Aqueous Ammonia and chloroform are immiscible.
- At what temperature should they be heated to produce the reaction?
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kmno4
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| Quote: |
NH3(aq) + CHCl3 => HCN + 3HCl
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It is not good equation.
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amchem2000
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| Quote: | Originally posted by kmno4
| Quote: |
NH3(aq) + CHCl3 => HCN + 3HCl
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It is not good equation. |
Correction1 -
NH3(aq) + CHCl3 => HCN + 3HCl(aq)
OR
Correction2 -
NH4OH + CHCl3 => HCN + 3HCl + H2O
So again,
- To what temperature should this "mixture" be heated?
- For how long (Give any reference amounts)
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DeAdFX
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If I remember correctly doesn't the reaction between ammonia and chloroform produce methylamine or some sort of methylamine derivative?
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