Hi
Could anybody tell me the temperature sodium cyanate decomposes into Sodium Cyanide Please??Iodobenzene - 28-12-2017 at 11:52
Hi!
Some time ago chemplayer posted a video about the reduction of cyanate to cyanide using carbon. ( https://m.youtube.com/watch?v=Z6s85zQHtxQ )
I hope this can help you.
Anyway Cyanide is an extremely deadly poison,i suggest you to avoid synthesising it unless you're an experienced chemist.
[Edited on 28-12-2017 by Iodobenzene]MattXaiMalachi - 30-12-2017 at 04:42
Thank you for the response
The temperature is around 450 degrees c if I have this right
Up to 530 for sodium considerably lower for potassiumJJay - 30-12-2017 at 05:59
Nurdrage has done it, but he stated in a later video that the product wasn't pure enough for his synthesis and that it required additional dangerous
purification steps that he did not disclose (likely something along the lines of: distill with dilute sulfuric acid to produce prussic acid,
neutralize with sodium hydroxide, precipitate with an alcohol, filter, dry, etc.). Magpie - 30-12-2017 at 09:47
Use carbon in a covered crucible. Check the cyanide thread for the temperature regimen.PirateDocBrown - 30-12-2017 at 11:22
I did it, too, with carbon. Small crucible, heat source was a Bernzomatic torch.
[Edited on 12/31/17 by PirateDocBrown]Iodobenzene - 30-12-2017 at 12:01
Thank you for the response
The temperature is around 450 degrees c if I have this right
Up to 530 for sodium considerably lower for potassium
I suggest you to work with potassium,not only for this reason.
Potassium salts are slighty more insoluble than sodium salts,so it's easier to recrystallize them.
Anyway nurdrage doesn't work in a very clean way,probably his cyanide was bad quality due to this.
Chemplayer never said his cianyde was bad quality. chemplayer... - 31-12-2017 at 16:08
The only method we've found which yields cyanide salts pure enough to use for synthetic purposes (and for nucleophilic substitution we've learned the
hard way that you NEED as high a quality as possible) is using sodium metal reacting with anhydrous potassium ferrocyanide. The process of reducing
cyanate with carbon will product a detectable quantity of cyanide salt but the product is highly impure.
We haven't tried Nurdrage's technique (cyanuric acid + NaOH if I recall) but no reason to believe it doesn't also work for a high purity product as he
went on and used it in a follow up reaction. No way he is 'less clean' than we are!Cryolite. - 31-12-2017 at 17:46
@chemplayer: NurdRage found that the cyanide produced in his video was far too impure for the synthesis of 4-chlorophenylacetonitrile. Instead, he
formed Prussian blue, filtered and washed it repeatedly to remove anything other than iron cyanides, and then converted it back to cyanide salts which
he could recrystallize. Kind of a pain in the ass really.Assured Fish - 31-12-2017 at 23:51
Then it would seem a better option would be to start from a pure source of the prussian blue pigment. I found myself a local source in NZ which means
it shouldn't be too difficult to find a source in other countries either. http://wendyls.co.nz/wendyls-shop/natural-bluing-powder-500g...
NurdRage apparently did this by calculating ferric ferrocyanide with sodium hydroxide.
This seems simple enough in theory however i haven't found any sources that report such a prep.
There is a thread opened in 2008 on the forum that discusses doing so by heating the ferric ferrocyanide in dilute H2SO4 producing HCN and then
bubbling this HCN through alcoholic sodium/potassium hydroxide. http://www.sciencemadness.org/talk/viewthread.php?tid=9820
This seems a little too dangerous to be worth the effort in my opinion.
I think a good repeatable way to produce pure sodium cyanide would be an excellent addition to the forum, I would also love it as ive been wanting to
use it to prepare dicyanoacetylene via neucleophilic substitution with diiodoacetylene for a while now.JJay - 1-1-2018 at 00:12
I hadn't seen Nurdrage's video with Prussian blue until recently... that looks somewhat safer than distilling prussic acid. Dan Vizine has discussed
producing cyanides with (IIRC potassium) ferrocyanide in some detail on the cyanide thread but stopped short of laying out a cookbook procedure.
chemplayer... - 1-1-2018 at 01:56
Ok sorry must have missed that bit, but that reflects our own experience - you need pure salts to perform reactions and get any sort of reasonable
yields.
Of the methods we've tried this only leaves the sodium metal + ferrocyanide method as the viable one then ('Erlenmeyer modification of the Rodgers
process'). Only question is would any other reactive reducing metals which are more easily obtainable than sodium have the ability to react and strip
those CN ligands away from the iron? Maybe worth experimenting with.
Certainly wouldn't mess around with trying to distill hydrocyanic acid. That is just madness and probably also not going to lead to pure products (due
to the ease of oxidation / reactivity of HCN).JJay - 1-1-2018 at 02:35
I think it is possible to distill it safely, and if that is done correctly (wash bottle filled with bleach keeping the fume hood air out of the
apparatus, etc.), it should lead to a fairly pure product, but cleanup would be fraught with peril.
I imagine other alkali metals would substitute for sodium... not sure about others....Radium212 - 1-1-2018 at 07:07
ChemPlayer reduced sodium nitrate to nitrite, maybe a similar procedure could be used.Magpie - 1-1-2018 at 08:25
Ok sorry must have missed that bit, but that reflects our own experience - you need pure salts to perform reactions and get any sort of reasonable
yields.
I prepared KCN by a carbothermic process described in the cyanide thread. The product was impure at 36.7% KCN. The is worked well as a catalyst for
the benzoin synthesis however:
I used 4X wt of my impure KCN to make up for the impureness. My yield was 60%.
MattXaiMalachi - 4-1-2018 at 07:24
Ok
I found what has been sold to me Pure Sodium Cyanate from a lab agency,
Am I right in thought that putting this with medicinal charcoal into a ceramic crucible heating the mixture to 550 degrees Celsius letting it cool to
harden after 25-30 minutes of melting the hardened residue should be Sodium Cyanide yes?
[Edited on 4-1-2018 by MattXaiMalachi]Magpie - 4-1-2018 at 09:11
Yes, you should get about 30-35% sodium cyanide. Let us know what you get.
Dissolve in warm water.Vosoryx - 4-1-2018 at 10:55
