Sciencemadness Discussion Board

Yes You Can Make Your Own TCT - If You Dare!

Sauron - 16-4-2007 at 11:22

This one not for the faint of heart. But if one really really needs cyanuric acid and cannot buy it (it is rather cheap) then here, courtesy of the great Otto Diels (same Diels of Diels-Alder fame) is lab scale prep of cyanuric chloride (aka trichloro-s-triazine).

Before launching into this let's look at the alternatives. CC can be prepared (or regfenerated from) cyanuric acid which you can buy by the bucketfull at swimming pool supply shos. However the fly in the ointment is that it takes very strong chlorinating reagents to do the job, only two that I know of are PCl5 (expensive and scarce) and oxalyl chloride (also expensive, but not so scarce.) If a more accessible chlorinating agent can be found that works then CC/TCT is OTC and the Diels procedure is passe.

The Diels procedure is very much aking to the industrial preparation of CC. Hydrocyanic acid (in German Blausaure) is reacted with chlorine in chloroform solution to form cyanogen chloride, which then trimerizes to cyanuric chloride. From 100g HCN the typical yield of CC is 110-120 g.

Diels described this in Ber., Jg 32 pp 691-702, attached below. The section on this prep is in first four pages. Balance of paper concerns reactions of CC and its daughter compounds, mostly aminotriazines.

Need I say, HCN is extremely dangerous. Cyanogen chloride even more so, and chlorine, although a walk in the park with your best girl by comparison, is not benign. Therefore, I am NOT advocating that anyone actually essay this procedure. Certainly not without a good hood and scrubber and the sort of safety equipment one would expect when working with the "blood agents" such as SCBA etc and first air supplies for HCN intoxication, like an oxygen tank and breathing mask, thiosulfate and methylene blue, etc. Finally since HCN tends to knock you out, don't do this alone! Someone competent needs to be nearby to assist you if you keel over.
All in all, BUY the stuff, if you can. I provide this article for informational purposes only. Meanwhile I am hunting down an alt prep from NaCN that at least eliminates handling of HCN although doubtless it and ClCN are still formed in situ.

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garage chemist - 16-4-2007 at 11:46

THANK YOU, this is now a new project of mine. This is the kind of chemistry I like, seriously! I have a good fume hood and over a liter of chloroform. The only thing thats lacking is a good source of HCN, I'll have to convert lots of ferricyanide for that.

Reaction of hydrogen cyanide with chlorine, to form cyanogen chloride, with subsequent trimerization to a powerful chlorinating agent, capable of converting acetic acid to acetyl chloride in high yield. This is mad science in its pure form.

I know exactly that I can do this in a safe manner, without harming myself, having done a lot of other "dangerous" procedures like synthesis of diethyl sulfate, distillation of mercury, distillation of dilute hydrazoic acid etc...

I'll give a translation of the procedure later.
Basically, the author only got monomeric ClCN upon reaction of HCN with Cl2 in CHCl3, and then found out by correspondence with the author of the original procedure that chloroform containing 1% ethanol must be used, as ethanol is the essential trimerization catalyst in this procedure.

[Edited on 16-4-2007 by garage chemist]

Sauron - 16-4-2007 at 12:23

And HCl, don't forget the HCl. HCl is catalyst for the trimerization. Lonza, the giant Italian HCN plant, patented the use of the diethyl ether-hydrogen chloride azeotrope for this purpose. Lonza, US 2 838 512, 1958 (M. Teysseire, H. P. Sieber). I'll post the patent text as soon as possible.

Ullmann's, which is where I found the Diels reference, says that Diels used HCl as catalyst.

I very much look forward to your translation and I am much gratified that you like the prep and actually want to do it.

Ullmann's rather teasingly says the most industrial production proceeds from HCN but sodium cyanide is a minor source. No reference damn it. So I have to go study ClCN chemistry yet again. Does NaCN react with Cl2?

I know there is a complex inorganic salt that produces ClCN directly, I believe it is a sodium zincate and I found it in Org Syn in a footnote, I believe it is also discussed in THE WAR GASES and maybe in Brauer. That might be a safer more convenient source of ClCN than HCN and Cl2. That is, if any sentence containing those compounds and the word "safer" retains ANY epistomolical value whatsoever...

Anyway I believe you are one of the few chemists on here who can do this and not hurt yourself. I would like to think I am another but I am not motivated as I have a lot of TCT and can get more anytime for little money.

I salute you, @gc! Bravissimo!

I looked up the Brauer reference. Pages 662-665 are attached. Two procedures. Both are from alkili cyanides. The first is the zincate I was thinking of, K2[ZN(CN)4] but you just make that in situ from KCN and ZnSO4. This is reacted with Cl2 to give 4 ClCN ) KCl + ZnCl2. NaCn and Ca(CN)2 are said to work equally well. The efficiency is very high and the ClCN very pure and chlorine free.

The second is NaCN + Cl2 as implied by Ullmann's. Sodium cyanide does react directly with chlorine (I should have remembered this!) I have not yet studied this one in full, I wanted to get this posted first so to save you the bother of looking it up. So if you can get NaCN, KCN or Ca(CN)2 you will be in business.

A few minutes later: OK it is now clear that the prep via the tetracyanozincate is preferred because the product is free of elemental Cl2 while that from direct reaction of cyanice and chlorine contains Cl2 which must be fractionated out, or the ClCN frozen and the chlorine removed in vacuo, then the ClCN fractionated, all of which sounds like a pain As the purity of the cyanogen chloride is key to avoiding premature (explosive! trimerization (also a great hazard with neat liq HCN) obviously the first procedure is the one of choice at least on bench scale.

[Edited on 17-4-2007 by Sauron]

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garage chemist - 16-4-2007 at 13:52

First method:

Into 325g chloroform (containing 1% ethanol), cooled by ice and salt, is passed 85g dry hydrogen cyanide gas (from 500g potassium ferrocyanide) (note: dont ask me how this is prepared from ferrocyanide, I would think that 500g should yield much more than only 85g HCN?).
Into this solution, still under cooling, is passed dry chlorine. When the mixture has assumed a yellow color, all hydrogen cyanide has reacted, but chlorine is still being absorbed, and it is practical to continue passing it in for some more time.
The mixture is left to stand for 12h, and is then refluxed until all HCl, excess Cl2, and unreacted ClCN have escaped.
The solution is decanted from an insoluble residue and chloroform and TCT separated by distillation.
The yield varies from 80g to 130g.

Second method:

Into 400g chloroform, containing 1% ethanol, cooled very good by ice and salt, is passed chlorine until saturation, which requires a large amount.
To this solution is added, from a dropping funnel whose pipe is drawn out into a capillary, 100g liquid anhydrous hydrogen cyanide so slowly and under simultaneous addition of more chlorine that the yellow color of the mixture never vanishes and chlorine is always present in excess.
If done correctly, this takes about 4-5 hours.
The mixture is left by itself in the freezing mixture, which is not being replenished. After this time, the TCT has crystallized in 7-8cm large, lustrous monoclinic prisms. The further conduct of the synthesis is done like above (distillation I assume).
This way, 110g, 105g, 110g, 120g TCT have been obtained from 100g HCN each in several subsequent batches.

I think it is obvious that the first method is more practical- I mean, adding liquid HCN from a dropping funnel?
The HCN may be conveniently weighed by liquifying it, but it seems way more convenient to first completely dissolve it in chloroform and then pass in the chlorine.

The HCl which is necessary for the trimerization as you say is generated by the reaction of HCN with Cl2.
But HCl alone is obviously not enough, as the synthesis is said to always fail, without exception, when the chloroform does not contain ethanol.

I think these methods, which trimerize the ClCN in the same pot as it is made are maybe somewhat safer than those (from Brauer) who first isolate the ClCN as a substance, though those again have the advantage of avoiding work with free HCN.

As ClCN is considerably more toxic than HCN (ClCN poisoning causes pulmonary edema by its strong irritating action to the lungs, rather than any toxicity by the HCN liberated by hydrolysis), I would prefer working with liquid HCN over working with liquid ClCN.

Sauron - 16-4-2007 at 15:08

In the group lab where I started as a research assistant, in one corner of the large room which had I think three or four 2 meter hoods, was a solvent still with a Kg of neat HCN refluxing. One or another f the group would occasionally draw off a small amount to use. My hood was a couple over. That was the one with the phosgene and ClCN half-cylinders down in the cabinet corroding away. I never messed with the HCN nor with the aging tanks, which were about 15 cm wide and 25 high. Nowdays I suppose everyone would be in moon suits.

Anyway, it's your call. BTW I was aways taught that ClCN has both PE and cyanotic action, and that the latter does not depend on hydrolysis. Cyanogen itself (CN)2 acts like HCN, ClCN is basically an interhalogen as -CN is a pseudohalogen. But, it doesn't matter. The salient point is not to breathe it. Also its lung irritant action is more like phosgene and less like chlorine, I suppose because the -CN group is so electronegative.

The military did not like ClCN much as it tended to eat everything they put it in and also has this nasty lil expl polymerization problem.

Very common practice to employ a small percentage of alcohol to stabilize chloroform, it absorbs phosgene which otherwise is autocatalytic in decomposition of CHCl3 and turns it into diethyl carbonate. So maybe phosgene negatively catalyzes this trimerization.

Benzene is alternate solvent. (sayeth Ullmann)

Here's the Lonza patent (1958)

They use dimethyl ether (not diethyl) azeotrope w/HCl as medium, this has a -2 C bp and the reflux serves to remove heat of reaction which they say otherwise leads to losses of ClCN and HCN.

Also yes the rxn releases HCl but they claim (and so does Ullmann) that additional HCl is used because the trimerization rate depends on HCl concentration. Higher rates achieved by adding more HCl than is generated internally. Anyway read the thing and see what you think.

[Edited on 17-4-2007 by Sauron]

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chemrox - 16-4-2007 at 18:48

An old adc guy whose stupidities included getting himself imprisoned by spilling his guts to the FL drug cops wrote a "FAQ" on making CNBr which may still be available in hive or rhodium archives .. anyway he was making the stuff in his apartment and woke up on the floor. He was very lucky. He was using an improvised 'hood'. I believe the design is another "FAQ" of his. The moral is: don't screw with this stuff .. if you like danger make nitro this or that .. much more fun.

Sauron - 16-4-2007 at 19:40

There are amateurs who are better equipped than some professionals and who have all the same skills. Read Org.Syn. Plenty of procedures employing HCN neat. NINE procedures with ClCN, more with BrCN, many with phosgene and many with H2S. H2S is the #2 killer in the petrochem industry, but it has not been demonized like those others.

But for joe average amateur with no hood and no SCBA I'd second your advice.

jon - 16-4-2007 at 20:23

what about using the sodium salt instead to prepare the cyanogen it seems safer to me, I know it can be done. one can blanket the sodium salt (undissolved) using chlorine gas with a series of ballons attached in line to aqaurium hose fitted with t-junctions the ballons act as a reservoir.
the setup would be A: chlorine generator goes to B: the reaction vessel which goes to C: the line of reservoir ballons.
once the cyanogen is generated you can add the solvent and filter off the salt and allow to trimerize.

to answer the question does the sodium salt react with halogens?

yes look at some of the BrCN procedures used in 4-MAR production they use the salt in methanol and add bromine to it this forms the cyanogen.

a side note I've read warnings that cyanogen halides and acids produce a violent exothermic reaction so you could very well end up with a plume of noxious cyanogens if your not careful one of the reasons a buffer is used in 4-mar synthesis.
[Edited on 17-4-2007 by jon]

[Edited on 17-4-2007 by jon]

[Edited on 17-4-2007 by jon]

tupence_hapeny - 23-5-2007 at 01:26

Here are two patents on the conversion of phthalic anhydride to phthaloyl chloride using phosgene (US Patent No.7154003 & US Patent App. No.2006/0122426 A1). They both use phosgene to chorinate the phthalic anhydride - however both achieve this end via the use of n,n-dialkyl-formamides, and as such achieve the chlorination of phthalic anhydride not directly from phosgene, but rather via the product of phosgene and the n,n-dialkyl-formamides (aka alpha-chloro-enamines), the uses of which are varied and quite interesting (such as chlorinating acyl chlorides for grignard reactions).

Obviously the reaction between cyanuric acid (which is a formamide derivative itself is it not?) is somewhat analogous to the preparation of a-chloro-enamines, so the procedure alluded to above should be of some interest.


[Edited on 23-5-2007 by tupence_hapeny]

Sauron - 23-5-2007 at 02:26

What leads you to conclude that cyanuric acid is a formaldehyde derivative?

Cyanuric acid is the trimer of HCN

Cyanuric chloride is the trimer of cyanogen chloride

No formaldehyde involved.

If you examine the structures of these and their tautomeric relatives you will find not a single methylene group to be had.

Cyanuric chloride is C3N3Cl3

Cyanuric acid is C3H3N3O3 and the hydrogens are on oxygen not carbon.

You are thinking of OTHER s-triazines, like RDX's parent skeleton cyclotrimethylenetriamine (which is of course NOT how one makes RDX...)

But cyanuric acid and cyanuric acid aren't formaldehyde derivatives unless you want to argue that HCN is a "formaldehyde derivative" -- which it isn't.

tupence_hapeny - 23-5-2007 at 06:02


I didn't say it was a 'formaldehdye derivative', instead I stated that for this purpose it should be seen as a 'formamide' derivative... The reason for which is so that it may be seen that it forms a form of a-chloro--enamine, which I suggest may explain it's power as a chlorinating agent. The basis of my claiming that it should be regarded as a formamide derivative is drawn from it's structure.

Here is the structure of cyanuric acid - note its two forms - both ((CO)NH)3 & ((COH)N)3:

Here is the structure of formamide - HCONH2:

In both cases the carbon is attached to an oxygen (either O or OH) and a nitrogen (n or NH) so I suggest that it should be treated (for the purpose of discussion only) as a similar compound - particularly with regard to its ability to form the basis of a-chloro-enamines (or whatever else TCT may be).

In fact, I may go further, for it is a cyclic version of a molecule differing from formamide by 2 hydrogens only - I would therefore suggest that it is nothing less than an oxidised form of formamide.


For all those reading this topic,

Phosgene is NO JOKE - it killed more people than any of the other war gasses in WWI - although people claim it was the deadliest chemical - which it most assuredly was not - TNT would take that title (nitrocellulose would not be far behind).

However, it is seriously nasty - a GOOD fume hood is the least of it, supplied or self-contained breathing air, a face shield etc. should be on when using this shit. Also, do not pump the hood into the air - this shit is denser than air and will kill you, your family, your dogs, etc. (or worse, your neighbours). There is no antidote and symptoms may take up to 48-72 hours to appear (the later the better). Treatment will save you - however, it will cause chronic lung damage - this is why so many WWI veterans died in the 1920's & '30's & those that didn't die young lived miserable...

To destroy it, react it with water - the reaction with air is too fucking slow apparently

Also, when prior to removing protective gear, wash EVERYTHING with lots of water and soap - then as it is removed - wash exposed skin thoroughly just in fucking case.

For details on this shit, see here:


PS If you don't have access to a hood, plastic chem suit, helmet w facemask, gloves and a scuba tank w mask - don't even fucking think about it.

Sauron - 23-5-2007 at 09:49

I reiterate: formamide is just as irrelevant as formaldehyde, to cyanuric acid, isocyanuric acid, cyanuric chloride and trichlotoisocyanuric acid.

The last one (TCCA) is the only chloro-enamine of the lot and it is made by chlorinating isocyanuric acid with Cl2. You can regenerate spent TCCA that way.

But cyanuric acid which is mostly in the isocyanuric form aty all times, is NOT prepared from formamide, it is prepared by the trimerization of HCN. HCN has a nasty habit of trimerizing on its own, explosively. Cyanogen chloride likewise trimerizes to CC (TCT) and that is the basis of its manufacture. All of the manufacturers of CC list it as part of their HCN product famil alone with malononitrile and chlorosulfonyl isocyanate.

You are simply trying to use a far fetched description of cyanuric acid and its relatives as formamide derivatives to justify interjecting a pair of patents about phosgene chlorination of phthalic anhydride into this thread where they really do not belong.

NO ONE is going to opt to prepare phthaloyl chloride from phosgene rather than with benzotrichloride, precisely because phosgene is every bit as nasty as you say.

Benzotrichloride is lachrymatory, but it is unlikely to kill you. It can be purchased freely, or made by perchlorinating toluene.

Maya - 23-5-2007 at 11:32

Would it be too presumptous to assume that cyanogen bromide would also undergo the analogous reaction?

Assuming I had cyanogen bromide but not the chloride?

Nicodem - 23-5-2007 at 11:56

Originally posted by tupence_hapeny
Phosgene is NO JOKE - it killed more people than any of the other war gasses in WWI - although people claim it was the deadliest chemical - which it most assuredly was not - TNT would take that title (nitrocellulose would not be far behind).

I really don't know what to think when I see someone so clueless about chemistry wiseassing with safety warnings. With all the misinformation you provide on daily basis, someone might be mislead to think this one about phosgene is just another one in the series. If it is so dangerous (and it really is!) then why you posted such a complicated, dangerous and tedious method for preparing phthaloyl chloride at all? As if there were no alternatives! Up to now I already figured it out that one of your aims is to make simple chemical transformation look terribly impossible for the average amateur though I have no idea why are you doing this, and if you are doing it consciously at all! But could you at least be so considerate to explain what the relevance of your post to this thread is? Not to mention your other off topic posts in the last week!

Sauron - 23-5-2007 at 17:58


Sartori in THE WAR GASES (q.v.) states that BrCN slowly polymerizes to cyanuric bromide, its trimer. He also states that distillation regenerates the cyanogen bromide. BrCN is of course a solid at ordinary temperatures while (BrCN)3 is a high melting solid with an mp somewhat higher than TCT - just as would be expected.

Therefore I would say your supposition was correct and that the accelerated trimerization of BrCN might be exploitable at a preparative route to TBT.

Alternative routes to TBT from TCT exist but are less attractive (except in that they do not involve handling toxic BrCN). See below

Some references to the other cyanuric halides:

J. Chem. Soc., 1964, 1020 - 1026, DOI: 10.1039/JR9640001020
197. 1,3,5-Triazines. Part IV. Phosphino-1,3,5-triazines
W. Hewertson, R. A. Shaw and B. C. Smith

"Extraction of the resulting oily solid with light petroleum (b. p.. 60---80°) left a colourless solid. Sublimation at 100-120"/01 mm. gave cyanuric bromide ..."

Q. Rev. Chem. Soc., 1962, 16, 1 - 18, DOI: 10.1039/QR9621600001
Direct structural evidence for weak charge-transfer bonds in solids containing chemically saturated molecules
O. Hassel and Chr. Rømming

"The struc-. tures of cyanuric bromide and iodide probably contain planar arrangements. corresponding to that of the cyanuric chloride (Fig. 9). ..."

Apparently all four cyanuric halides exist and have been characterized, but only TCT has achieved industrial importance and been commoditized, which it is why it is so reradily available and inexpensive as a lab reagent. Thank you, agro-industry!

There are a bevy of patents naming cyanuric bromide, etc as intermediates, just Google on cyanuric bromide and it will spew them forth. I will concentrate on the chemical literature proper as it is more likely to give us clues as to preparation, stability, etc.

1,3,5-Triazin-2,4,6-trisulfenyltrichlorid: Schwingungsspektren und Molekülstruktur
Journal Monatshefte für Chemie / Chemical Monthly
Publisher Springer Wien
ISSN 0026-9247 (Print) 1434-4475 (Online)
Issue Volume 129, Number 2 / February, 1998
DOI 10.1007/PL00010150
Pages 139-149
Robert Tripolt1, Edgar Nachbaur1
1Institut für Anorganische Chemie der Karl-Franzens-Universität Graz, A-8010 Graz, Austria


Summary. The IR, FIR, and Raman (solution and solid state) spectra of 1,3,5-triazine-2,4,6-trisulfenyltrichloride ((NCSCl)3) were investigated for the first time. It was possible to identify all fundamentals in the solid state spectra which were assigned on the basis of a planar molecular structure with C3h symmetry. On the other hand, the solution spectra reveal unambiguously the presence of a conformer of lower symmetry (Cs) in equilibrium with the C3h isomer. Calculations employing the density functional theory were performed (B3LYP/6-31G*). A comparative discussion of the vibrational spectra of (NCSCl)3 (C3h) with respect to those of cyanuric fluoride ((NCF)3), cyanuric chloride ((NCCl)3), and cyanuric bromide ((NCBr)3) reveal a significant dependence of the vibrational situation within the 6-membered heterocyclic ring system on the different substituents in 2,4,6-position. Some modes of 2,4,6-trihalogeno-1,3,5-triazines have been reassigned, e.g. the normal mode v12 of 2,4,6-trifluoro-1,3,5- triazine.

[Edited on 24-5-2007 by Sauron]

[Edited on 25-5-2007 by Sauron]

Organikum - 23-5-2007 at 18:28

Ullmanns is known to to be horribly incorrect in patent references be warned! Simple mistakes like confusing ethelene glycol with glycolic acid make some big differnces in reasons of practicabiliy.

[Edited on 5-24-2007 by Polverone]

Organikum - 23-5-2007 at 18:40

There was no technically relevant content in this post.

[Edited on 5-24-2007 by Polverone]

Sauron - 23-5-2007 at 19:23

Aldrich sells cyanuric fluoride CAS 675-14-9
It is described as reagent for preparation on carboxylic fluorides. References:

3. G.A. Olah et al. Synthesis, 487, (1973)

4. M.J.S. Dewar, I.J. Turchi J. Org. Chem. 40, 1521, (1975)

Pretty stellar authors: Olah and Dewar! I will retrieve these (have one on my hard disk) and post them here.

The Olah article describes preparation of cyanuric fluoride from CC and dry HF in polyolefin apparatus. Yield 75% and can be improved upon by recycling byproducts cyanuric difluoride chloride and cyanuric dichloride fluoride.

The Dewar article simply includes a modification of Olah's procedure for preparaing carboxylic acid fluorides so I will not post it here.


I found a description of the preparation of cyanuric bromide (TBT) but I doubt it is very preparatively useful. It starts from TCT, proceeds through tris(disalkylphosphino)-s-triazines which are cleaved with Br2 then the product liberated with dry SO2, all this was done on a low gram scale. TBT is a colorless solid mp 265 C.

It is stated that pure cyanuric iodide has not yet been prepared.

What I am still looking for is practical preparative method for cyanuric halides other than the chloride from the corresponding cyanogen halides.

[Edited on 24-5-2007 by Sauron]

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tupence_hapeny - 24-5-2007 at 11:00

Nicodem said
But could you at least be so considerate to explain what the relevance of your post to this thread is? Not to mention your other off topic posts in the last week!

Nice to see ya, my point was (and here sauron is wrong, TCCA has the N-Cl bond, chloro-enamines have a C-Cl bond - just like CC) that cyanuric chloride is basically an a-chloroenamine (namely the chlorine is attached to the a-carbon of a compound with a C-N linkage). Thus it is of the same family of compounds as the ones that do the work in BOTH of the irrelevant patents cited - a-chloro-enamines and as such could be achieved to via phosgene and cyanuric acid - which insofar as the intrinsic danger of the reactions is a tossup with the one suggested - using cyanide to make cyanogen chloride if I read it right? It all comes down to whether one wishes to die with the lingering smell of hay or almonds, right?

Anyhow, as to the relationship between nitriles etc. and formamide/methylamine, see this - wouldn't this make methylamine from cyanuric acid?


Nicodem - 24-5-2007 at 11:37

Formaly, the total hydrogenation of any cyanogen halide, HCN and HOCN gives methylamine. But the (formal) hydrogenation of cyanuric acid, cyanuric chloride or s-triazine gives a mixture of methylamine, dimethylamine and ammonia. Mind that these transformation are only formal! In reality they might be near to impossible to accomplish and the side reactions in the reduction of the listed monomeric species also give dimethylamine and ammonia.

[Edited on by Nicodem]

Sauron - 24-5-2007 at 18:10

I prefer to adhere to the classification of derivatives as arising from what they ACTUALLY derive from.

Lonza and the other makers of cyanuric chloride place it in their HCN platform because they make it from HCN.

They also place malononitrile in same platform because it too is produced from HCN.

In classifying nitriles, HCN and cyanogen are the root. There are no simpler compounds with a C-N triple bond. While any competent organicker will recognize that dehydration of formamide would giv rise to HCN, just as dehydration of acetamide produces acetonitrile, nitriles are not regarded as derivatives of carboxylic acid amides.

I cited a reaction that will WORK. Tup proposed a reaction that has not been demonstrated, on the basis of his unsupported opinion that TCT is derived from formamide. I do not believe any reaction of any formamide with phosgene will give rise to any cyanuric acid derivative. I can show you how acetonitrile can be used to produce SATURATED s-triazines related to RDX. In fact I have already done so on this form. Note, I said acetonitrile not formamide and NO phosgene was involved. And anyway the products are not cyanuric acid derivatives unless you wanbt to stretch a point way past absurdity.

Cyanogen Cyanide chemistry

franklyn - 16-2-2008 at 11:37

The Chemistry of Cyanogen Compounds and Their Manufacture and Estimation
Herbert E. Williams - 1915
Also covers fulminate compounds
Page 177 gives this reference for Cyanuric chloride, needs phosphorus pentachloride though.
Beilstein, A., 116, 357


S.C. Wack - 2-6-2008 at 13:41

On page 10 of the above book is a mention of Liebig obtaining it by heating KSCN in chlorine. Watts had the citation and Gallica had the article, Pogg. Ann. (Annalen der Physik) 35, 604 (1835). The procedure yielded very badly but it is an alternative to HCN.

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Formatik - 2-6-2008 at 14:50

Another way to obtain it without HCN is by heating dry cyanuric acid and PCl5: 3 PCl5 (s) + 2 (CNOH)3 (s) = 3 POCl3 (l) + 3 H2O (g) + 2 (CNCl)3 (s) + 76.8 Cal., this reaction is said to be strong, but still less exothermic than the chlorine and HCN (244.4 Cal.). This method is the one by Beilstein in Annalen der Chemie, 116, 357. Also in place of HCN, moist Hg(CN)2 can be used as was done by Serullas (this is either in Ann. Chim. Phys. 35, 291; 337; or 38, 370).

[Edited on 2-6-2008 by Schockwave]

Jor - 2-6-2008 at 15:10

To many of us, PCl5 is not available. If one has PCl5, there's no need for TCT AFAIK

Formatik - 2-6-2008 at 20:57

Originally posted by Jor
To many of us, PCl5 is not available.

Come on where is that amateur spirit? Simply just make your own phosphorus pentachloride. :D

If one has PCl5, there's no need for TCT AFAIK

That depends on what you are trying to do, for a chlorinating agent if you have PCl5 then you likley won't need it, as a reactant in other reactions you will.

Klute - 2-6-2008 at 23:45

In some insatnce you can't use PCl5 for chlorinations, if you product has the same bp as POCl3 for example. With TCT, all you need to do if filter the cynauric acid!

I really think the method Sauron advocates ei chlorinating CNCl through it's in situ formation by chlorination of alkyl/alkali thiocyanates is really a good idea, and the mosyt practical way to do so. If you are carefull enough and think your way through, generating large amouts of chlorine gas safely isn't very hard, dangerous or expensive, and the reaction yields very usefull/hard to get products.

Obviosuly, if you have a good source of red phosphorus (read not match boxes ;) ), you can make PCl5 in a easier way IMHO.

Sauron - 3-6-2008 at 00:15

As the thread author, I'd like to point out that the prep of TCT by the trimerization of cyanogen chloride, as described above, is a very hazardous procedure. There is a far safer process for preparing TCT, which is the chlorination using elemental chlorine, of methyl thiocyanate.

I have described this chlorination elsewhere, q.v. the product initially is a mixture from which TCT precipitates out in good yield. Chlorination is continuied till no more TCT seperates. The supernatant liquid mixture is a mixture of CCl3SCl, which is toxic and highly irritating, and CSCl2, also toxic and irritating. But these liquids are a lot less toxic than the gaseous HCN and ClCN involved in the other procedure.

Exhaustive chlorination of the mixture leads to CCl2 and sulfur chlorides.

From 100 g MeSCN aboit 65-70 g TCT is obtained.

The stoichiometry is given in the other thread, along with the original literature.

For those in the EU where TCT is often classes too toxic to sell to individuals, this is a good alternative. Methyl thiocyanate can be prepared from KSCN and iodomethane or dimethyl sulfate, or by a somewhat more circuitous route starting with CS2.

Chlorination of cyanuric acid with PCl5 is terribly reagent intensive. Look at the stoichiometry and the molecular weights involved and you will see what I mean. This is also the case with the preparation of oxalyl chloride from PCl5. This simply not a very practical method, unless you have no other choice. This is without consideration of the logostical difficulties. PCl5 IS hard to obtain. Red P to make it, IS also hard to obtain in most places. PCl5 could be made from PCl3 but that is also hard to purchase.

[Edited on 3-6-2008 by Sauron]

trilobite - 3-6-2008 at 12:21

Here's a patent on production of cyanogen chloride from sodium cyanide and chlorine in organic solvent in the presence of a small amount of ethanol. They say that adding more than the required amount of chlorine should be avoided. Who knows, maybe it's to avoid tri/polymerization.

Process of making cyanogen chlorides

Sauron - 4-6-2008 at 06:11

Making cyanogen chloride is not difficult. It's surviving the making of cyanogen chloride that is the trick.

The point of my last post was a better way of making cyanuric (NOT cyanogen) chloride (TCT) WITHOUT having to make cyanogen chloride even in situ.

No one who does not have an industrial grade scrubber and hood AND a SCBA should attempt making cyanogen chloride. To do so in a residential environment is to put your family at riak and possibly your neighbors as well. It's irresponsible.

The alternative I presented involves some toxic irritants but they are liquids not gases and therefore a lot easier to control. Once the pptd TCT is removed, these are to be exhaustively chlorinated to CCl4. There's no other product except chlorides of sulfur. There is no explosion hazard as there is with cyanogen chloride. My advice is leave that route to industry.

trilobite - 4-6-2008 at 07:49

Understood. My purpose, on the other hand, was to contribute to the discussion by finding a literature reference for making cyanogen chloride in nonaqueous conditions from NaCN without the need to handle HCN. This must be the right thread also for this piece of information considering all the material posted here on routes which employ HCN. Of course, there is a lot more to succesfully making TCT by one pot chlorination of NaCN and trimerization without killing oneself or others.

I assume people reading this thread have already understood they should not attempt this stuff without necessary precautions. I myself am only interested in this stuff from the theoretical point of view because neither route is really my cup of tea. ;)

Sauron - 4-6-2008 at 16:58

At the time I started this thread I was unaware of the MeSCN chlorination approach to making TCT. Garage chemist and I had discussed the other methos.

I can assure you that I would not have posted the HCN/cyanogen chloride based route at all, but only the MeSCN chlorination, if I had then what information is on hand now.

Cyanogen chloride combines the properties of HCN and phosgene. The latter is scarier than the former. One of our members recently confirmed this, he accidentally produced a little phosgene in his lab and can now tell you all about its famous scent. Fortunately he came away with merely a week's painful asthma-like symptoms, but no pulmonary edema.

Drowning in your own fluids is nature's way of telling you to slow down.

unome - 4-11-2009 at 23:59

Thought these might be interesting... On reacting glycine with 3 equivalents of hypochlorite, researchers have found that it produces cyanogen chloride ...

It sounds a little far out and not reading Japanese all that well, it is difficult to ascertain whether this could be useful, although there are a couple of JACS articles that might be of more utility (Mechanism and Kinetics of Cyanogen Chloride Formation from the Chlorination of Glycine & Stability of Cyanogen Chloride in the Presence of Free Chlorine and Monochloramine...

I also threw up the articles in question, as well as a couple of others which might throw some light upon the subject...

Attachment: BreakpointChemistryOrganic.Byproduct.formation.Chlorination.pdf (165kB)
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Attachment: Byproducts.Oxidation.Water.pdf (1MB)
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Attachment: Glycine.Hypochlorite.I.Cyanide.Cyanogen.Chloride.pdf (571kB)
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Attachment: Glycine.Hypochlorite.II.Cyanide.CyanogenChloride.pdf (605kB)
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Attachment: Oxidation.aminoacids.2.cyanides.DAKIN.pdf (462kB)
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