Sciencemadness Discussion Board

5-ATZ(5-Aminotetrazole), the nitrotetrazolate ion and friends

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Rosco Bodine - 14-6-2011 at 18:20

This is being posted here as nitrotetrazolate related hypothetical material even though the same post is being duplicated in another older thread as a followup there.

http://www.sciencemadness.org/talk/viewthread.php?tid=10969#...

Guanyl Azide may possibly form an interesting salt with 3,5-dinitro-1,2,4-triazole. I am uncertain how it may be done, but speculate it may be possible to first form the aminoguanidine salt of 3,5-dinitro-1,2,4-triazole as an
intermediate.

Attached are some references. Guanazole would be gotten from Dicyandiamide reaction with hydrazine as per US2648671. Hydrazine Sulfate could be converted to the Hydrazine Dihydrochloride via Calcium Chloride and filtering.

Guanazole (DAT) is diazotized to 3,5-dinitro-1,2,4-triazole as per the method described on page 13 of the Los Alamos technical report attached.

The DNT is neutralized with aminoguanidine bicarbonate or
a double decomposition of perhaps a soluble sodium DNT salt with a soluble aminoguanidine salt perhaps the nitrate,
may work.

Then the aminoguanidine 3,5-dinitro-1,2,4-triazole is converted to the azidoformamidinium 3,5-dinitro-1,2,4-triazole per the method used for conversion of aminoguanidine perchlorate to azidoformamidinium perchlorate. See Klapotke paper attached, regarding compound 4 page 3.

No search has been done for the speculated compound
azidoformamidinium 3,5-dinitro-1,2,4-triazole ....
existence and properties at this point unknown.

Perhaps this could be a "green primary" class material
or a candidate for investigation.

Attachment: US2648671_PREPARATION_OF_GUANAZOLE.pdf (84kB)
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Attachment: Diazotization of Guanazole to Dinitro Triazole 00312939.pdf (1.5MB)
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Attachment: Aminoguanidine Perchlorate, Triaminoguanidine Perchlorate, Guanyl Azide Perchlorate.pdf (316kB)
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[Edited on 15-6-2011 by Rosco Bodine]

AndersHoveland - 23-6-2011 at 15:13

Quote: Originally posted by Rosco Bodine  

The DNT is neutralized with aminoguanidine bicarbonate or
a double decomposition of perhaps a soluble sodium DNT salt with a soluble aminoguanidine salt perhaps the nitrate


One minor, yet important correction. DNT (or its salts) can actually be reduced by hydrazine to form 3-amino,5-nitro-1,2,4-triazole (ANTA). A similar reduction would be expected if using aminoguanidine instead of hydrazine.
While the reaction is rapid at 80degC, the reaction is supposedly slower at room temperature, and it is doubtful that a dinitrotriazolate salt of aminoguanidine, if it exists, would be chemically stable for more than 24 hours.

Rosco Bodine - 23-6-2011 at 15:35

That very well could be true. If reduction of DNT by aminoguanidine does occur instead of a salt formation, then a workaround would be to first convert the aminoguanidine to a guanylazide salt and subsequently react with a salt of DNT.
For example perhaps guanylazide nitrate reacted with sodium DNT would accomplish the swapperoo .......er double decomposition. Reaction of guanylazide perchlorate with ammonium DNT might work also.

[Edited on 24-6-2011 by Rosco Bodine]

AndersHoveland - 23-6-2011 at 16:05

Rosco, you do realize that boiling aqueous guanylazide, in the presence of either a weak base or weak acid, results in cyclization to 5-aminotetrazole?

Why not just try to prepare 5-aminotetrazole-3,5-dinitrotetrazolate? It would likely not be any less powerful, and it certainly would be much less sensitive.

There are also dinitrourea salts:
http://docs.google.com/viewer?a=v&q=cache:z1Z4ai1F7qkJ:p...

[Edited on 24-6-2011 by AndersHoveland]

Rosco Bodine - 23-6-2011 at 16:25

Yes I do understand the reaction sequence continued past the guanylazide intermediate leads to a non-sensitive 5-aminotetrazole product, and so does the decomposition of tetracene .....however the 5-aminotetrazole DNT is not the compound of interest, as sensitivity is a property which was desired. Dinitrourea salts would not be expected to be as stable as a DNT salt.

Regarding the 5-aminotetrazoleDNT, granted it does make sense what you say that it would likely not be any less powerful than the guanylazide DNT derivative, however the guanylazide group is probably going to be a more sensitive energetic group than an aminotetrazole. A "green primary"
is really more what I was contemplating.

It would be expected that for the triazole compound it would be true the same way as for the tetrazole compound, that
an aminotetrazole group would be non-sensitive energetic while an azide group would be favorable to making the azole a more sensitive explosive.

Edit (amended and corrected for clarification)


[Edited on 24-6-2011 by Rosco Bodine]

AndersHoveland - 23-6-2011 at 16:49

You do realize that 5-amino tetrazole can be detonated? Just because it is not sensitive does not mean it is less powerful.

I did not understand you post above, perhaps you should carefully reread my earlier post to be sure you understood it. To repeat, I am saying that
guanylazide NH=C(NH2)--N=N[+]=N[-] , despite being very sensitive, is probably not more powerful than
5-amino-tetrazole NH2--(CN4H).

Notice that both compounds have the same formula: CN5H3
Although azido groups are more powerful than amino groups, one could also similarly/inversely say that tetrazole groups are more powerful than guanyl groups. Hopefully you understand what I sam trying to say.

Although cyclization of the guanyl azide adds stability (thus reducing heat of formation), the bond strain from the 5-membered ring somewhat compensates for this. In addition, the presence of the ring would be expected to increase density. It should also be remembered that in high nitrogen-content explosives without oxygen, heats of formation are less important, as such compounds are more entropic explosives, meaning that the explosive power comes more from the normal volume of the resultant gas products than the quantity of heat generated to expand the gases.

In any case, sacrificing a little performance would be well worth the decrease in sensitivity. In either case, most of the energy would come from the dinitrotriazolate anion, so the power contributed by the cation would be less important. Just my opinion.


[Edited on 24-6-2011 by AndersHoveland]

Rosco Bodine - 23-6-2011 at 18:37

You mean most of the energy would come from the dinitrotriazolate (DNT) rather than dinitrotetrazolate

Edit: I actually did misunderstand above what you were saying and have amended the earlier confused reply above.

The aminotetrazole salt of DNT which you propose is likely
energetic and a valid compound, but is probably non-sensitive as you suggested. It would probably have usefulness in other ways but likely not be promising as a
"green primary".

It is not any reduction in sensitivity which is being sought.
It was a "green primary" which was the nature of the speculative hypothetical compound.

Attached is an old journal article which describes the preparation of guanylazide nitrate from aminoguanidine, and also describes conversion to 5-aminotetrazole via sodium acetate, as well as how sodium azide may be gotten from guanylazide reaction with sodium hydroxide in excess.

Attached also is a second old journal article describing early identification of structure and general properties.

Attachment: Pages from Journal_of_the_Chemical_Society.pdf (169kB)
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Attachment: Guanylazide Nitrate from Aminoguanidine.pdf (289kB)
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[Edited on 24-6-2011 by Rosco Bodine]

azobisformamidine salts

Rosco Bodine - 23-6-2011 at 23:41

Azobisformamidine dinitrate is gotten from aminoguanidine
nitrate in solution in dilute nitric acid via oxidation by KMnO4
and azobisformamidine is dibasic which could form a series of explosive salts. Azobisformamidine Diperchlorate could be interesting, as could many other potential salts or double salts. Possibly it could form a diazide or an azide - picrate or a nitrate - perchlorate or a styphnate or a nitranilate. And of course it may also form a salt of interest with DNT.

Attachment: Azobisformamidine Dinitrate Vol. 1 PATR.pdf (88kB)
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Attachment: Aminoguanidine related _chemistry_.pdf (208kB)
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Attached also is the page 447 referenced with regards to carbamic acid azide to which the azobisformamidine is converted by boiling water.

Attachment: Carbamic Acid Azide page 447.pdf (188kB)
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[Edited on 24-6-2011 by Rosco Bodine]

Rosco Bodine - 28-6-2011 at 17:55

On the first page of this thread I posted a patent
US3663553 Di-Silver Aminotetrazole Perchlorate
and it is attached again here along with a related
paper as a followup describing that and similar
silver compounds.



Attachment: US3663553 Di-Silver Aminotetrazole Perchlorate.pdf (101kB)
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Attachment: 5-Aminotetrazoles and Silver-based Primary Explosives.pdf (853kB)
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Guanidine to aminotetrazole

Boffis - 12-7-2011 at 10:30

Hey Rosco the last two attachments in your post of 24-6-11 appear to be from a google book. Please could you give us the title and auther?

I am working on some similar chemistry after I read in an old chemistry text that guanidine racts with 1 molar equivalence of nitrous acid to give diazoguanidine and then a second mole of nitrous acid to give aminotetrazole. The equation isn't balanced and it hard to see how it could work since the reaction needs to get a lot of hydrogen from somewhere so I decided to investigate it the reaction. The work is still in progress but this is where I have got to, my conclusion is that about half of the guanidine is consumed as a reducing agent and nitrogen being liberated.

5-aminotetrazole from guanidine hydrochloride

In H. E. William’s The Chemistry of Cyanogen Compounds (1948 edition) p43 he refers to the reaction of nitrous acid with guanidine. He states that it progresses in three stages each one reacting one molar equivalent of nitrous acid with the guanidine to give diazoguanidine then amidotetrazole (=5-aminotetrazole) and finally an explosive diazotetrazole.



5 Aminotetrazole p43.jpg - 37kB

Boffis - 12-7-2011 at 10:50

The reaction scheme above is difficult to describe in terms of a balanced equation; in order for the reaction of the diazoguanidine to proceed to aminotetrazole reduction or transfer of electrons is required. However, during small scale reactions using 2.87 gm of guanidine hydrochloride (0.03M) per experiment gas was evolved that although brown appears to consist mainly of nitrogen with only a little nitrogen oxides being present. It is probable therefore, that some of the guanidine is oxidized.

Since this series of reactions appears to offer a route to 5-aminotetrazole form cheap if not exactly OTC chemicals it was decided to carry out some experiments to determine reaction conditions and establish yields.

Numerous small scale experiments were carried out using guanidine hydrochloride or sulphate with two molar equivalents of sodium nitrite and various acids (HCl and acetic acid) and on occasions the addition of various reducing agent. The idea behind the addition of the latter was that if nitrogen is being evolved guanidine is being hydrolysed and oxidized and therefore the addition of a reducing agent may increase the yield from guanidine. Sodium sulphite and metabisulphite were added either after the addition of one or two molar equivalents of sodium nitrite, the idea behind the addition after one equivalence of sodium nitrite was to reduce the intermediate diazoguanidine to aminoguanidine (by analogy with the reduction of diazotized aniline to phenylhydrazine), however, although some strongly exothermic reactions were encountered no aminoguanidine or aminotetrazole resulted. The preparation given below is the results from the scaling up of the best preparation to date. Scaling up the reaction makes it easier to handle and reduces mechanical losses.

Theory
Based on William’s scheme one molar equivalent of guanidine hydrochloride should reacts with two molar equivalents of sodium nitrite and one equivalent of hydrochloric acid to give aminotetrazole. Only one equivalent of hydrochloric acid is required because the guanidine is already combined with one equivalent of hydrochloric acid which is liberated when the diazoguanidine is formed. Curiously the yield was significantly improved when only half this amount of hydrochloric acid was added initially.

Preparation details
28.9gm of guanidine hydrochloride (actual weight 0.3M) were dissolved in 30ml of water, solution occurred quickly at room temperature. 42.7gm of sodium nitrite (0.6M) were dissolved in 60ml of water in a separate vessel, gentle warming was necessary as the nitrite solution becomes very cold. Both solutions were then chilled in the fridge to about 5°C and then mixed before 16ml of 30% HCl (0.15M) diluted with 16ml of water were added fairly slowly (over 4-5mins) with gentle swirling to minimise gas loss (Note 1). The solution turned greenish blue and a very small amount of brown nitrogen oxide was evolved. The solution was placed in the fridge at 3°C for 18 hours over which time it turned yellow and a frothy layer of crystals separated (Note 2).

The crystals were removed by filtration in a Buchner funnel and dried at 35 to 40°C for 24hrs. The yield was 6.10 gm of slightly cream coloured crystals. A small quantity was burned in a small crucible and left practically no residue of salt. Interestingly when the dried crystals were removed from the filter paper a trace of a very fine bright yellow powder remained adhering to the paper, this material deflagrates vigorously without charring the paper when heated suggesting that it is some form of diazoaminotetrazole derivative and it is probably responsible for both the colour of the solution and the recovered crystals (Note 3). Work to confirm that the crystals are 5 aminotetrazole has not yet been undertaken.

The yellow filtrate was chilled to near 0°C and a further 16ml of 30% HCl added slowly, the solution turned bluish again but it was harder to minimise gas loss this time. The solution was placed in the fridge for 24hr; no crystals formed.

The solution was placed in a 250ml squat form pyrex beaker and slowly evaporated to approximately 130ml. Copious quantities of white crystals formed rapidly as evaporation progressed but it is important not to go below 130ml as this volume of solution is required to keep the sodium chloride in solution. The solution was cooled to room temperature, filtered at the pump and dried as before yield 13.01gm. The solid was visibly a mixture of colourless platy crystals, white granular material (salt?) and a small amount of a fine grained bright yellow powder. Further tests show that it contains a large amount of sodium chloride and work is in hand to determine the best means of extracting the organic material. The yellow powder is sparingly soluble in water and as with the previous crop is probably a diazoaminotetrazole derivative of some form.

Loss of access to the laboratory until September has prevented further investigation and purification of the product (Note 4). However, given the significant amount of salt in the second crop the total yield of aminotetrazole, assuming that is what it is, is no more than about 50%. (Theoretical yield of 5-aminotetrazole would be 31gm)

Note 1 Mechanical stirring caused copious gas loss and significantly reduced yields.

Note 2 Experiments with acetic acid allowed all of the acid to be added at once without excessive loss of nitrogen oxides but the initial yield was only about 10-12%. This may be because acetic acid is too weak to protonate the tetrazolate ion even when concentrated by evaporation and the sodium aminotetrazolate is more soluble than the free base.

Note 3 Given the similarity of this reaction with that described Sci. Madness, 5-ATZ(5-Aminotetrazole), the nitrotetrazolate ion and friends, Engager, 8-1-2006; “Synthesis of sodium 5,5 diazoaminotetrazolate from aminoguanidine” the bright yellow substance my well be the diazoaminotetrazole or its Na salt.

Note 4 Further experiments to isolate the first formed diazoguanidine and to reduce it to aminoguanidine will be attempted later but preliminary experiments did not appear promising.



5 aminotetrazole x guanoHCl.JPG - 59kB 5-amionotetrazole from guanidineHCl.JPG - 80kB

LEFT After 24hr in the fridge; note the frothy floating platy crystals of aminotetrazole. RIGHT 5 aminotetrazole from the first crop of crystals (these are from earlier small scale runs)

Rosco Bodine - 13-7-2011 at 01:54

Please post a link to the 1948 edition of Williams. That earlier excerpt was from Victor von Richter Organic Chemistry 1916

Boffis - 13-7-2011 at 05:57

How can I post a link to the 1948 edition of Williams when I can't find one except as a second hand book on Amazon? Thats why I gave the full reference and and a scan of the relevant section. The 1915 version is available as a download free at;[url=http://www.archive.org/details/chemistryofcyano00willrich]

I can see little point posting a link to a book on Amazon since when the book is sold it will become and orphan link and Science Madness has enough of those already. After I bought my volume it wasn't available as an original until recently (there is currently one available), the 2010 reprinted versions are mostly the earlier 1915 edition and these do not carry the quoted text.

Boffis - 13-7-2011 at 10:58

Thanks for the title! I have manage to download a free copy of Von Richter.

For comparison and in order to have enbough certain 5 aminotetrazole to work with I made some using the dicyandiamde - sodium azide method in US patent 5451682.

This preparation was take almost verbatim from the US patent 5451682 (link already presented earlier in this post) apart from being scaled up by a factor of 5. Since I have access to dicyandiamide I used Experiment 2 in the above patent. The only variation was accidental! I had originally planned to scale up the reaction by a factor of 10 but discovered I didn’t have enough sodium azide and so scaled back the preparation, unfortunately I forgot that I had already measure out the hydrochloric acid for the final acidification at the x10 ratio. I realized as soon as I had added the HCl that I had added too much and added an appropriate amount of 10M sodium hydroxide solution to neutralize half the acid but this of course significantly increased the volume of solution and may have lowered the yield.

Preparation details
In a one litre single neck flat bottom flask equipped with a magnetic stir bar and reflux condenser were placed 50.0 g of dicyandiamide, 38.71 g of sodium azide and 55.0 g of boric acid in 500 ml of de-ionised water. The solution thus obtained was brought to reflux by which time it had turned slightly orange. The reaction was allowed to proceed under gentle reflux for 24 hours and then 150 ml of 35% HC1 (1.75M) was added while the solution was still hot. As mentioned above this is twice the required amount of HCl according to the patent so 87.5ml of 10M (0.875M) sodium hydroxide solution had to be added to neutralize the excess acid.

The clear reaction mixture was cooled in a fridge for 18 hours where upon a small amount of a white crystalline solid had formed. The mixture was vigorously stirred to promote crystallisation and left in the fridge for several more hours. The crystalline product was isolated by filtration however, as filtration proceeded further product crystallized on the stem of the Buchner funnel and in the filtrate. As much of the product as possible was scraped from the inside of the funnel stem with a spatula and the filtrate stirred vigorously again before being returned to the fridge for a further 6 hours with frequent vigorous stirring before being filtered through the same funnel as before. The resulting cake was pressed down and washed twice with 150 ml portions of ice cold distilled water. The solid was then dried in warm oven at about 40°C for 12 hours to the dry monohydrate. The dried product weighed 65.45gm, 90.3% and had the form of pure white fine bladed crystals.

Note; some loss occurred through crystallisation of the material inside the Buchner funnel and this was not recovered. A further small amount of crystalline material had formed from the final filtrate when I came to dispose of it! This was not recovered but in any further preparation I will allow 2 to 3 days in the fridge with frequent vigorous stirring before filtration.

Rosco Bodine - 13-7-2011 at 11:20

FYI, I already had the scanned first edition from 1915 and your excerpt is not in the earlier edition and appears to be obscure, so if there was a scanned second edition out there it would be better to have the later edition. I was hoping your excerpt was not a scan from your own hard copy. No such luck huh. I knew about the probable route from guanidine using reaction with hydrazine to form an aminoguanidine intermediate, but Williams describes dispensing with the hydrazine and getting right to business nitrosating the guanidine which is the first time I have seen this described as a direct route being possible, even though the name of the compound diazoguanidine would suggest it may be possible
to diazotize guanidine itself instead of diazotizing aminoguanidine. Diazoguanidine and 5-aminotetrazole are isomers and both are monobasic.
It seems possible there could be a monomer - polymer or purely structural difference there more than any significant electron richer / poorer ionic sort
of difference. It is more a structural kind of thing like a piece of nitinol wire
that transitions from a straight length to a latched ring structure, if I understand correctly. Perhaps another way of looking at it would be the diazoguanidine is like a bimetal strip with opposite polarity magnetic poles at each end, and when heated it curves around into a loop and snaps together firmly to form the 5-aminoguanidine ring structure.

[Edited on 14-7-2011 by Rosco Bodine]

Engager - 13-7-2011 at 16:18

This is interesting stuff, however constitution of product is very uncertain. First of all look at reaction from your picture it actually suggests 5-amino-2H-tetrazole witch is different compound with common 5-ATZ witch is 5-amino-1H-tetrazole, i know that 2H isomer exists however i don't know it's properties. Second concern is that i don't see any reasonable mechanism witch can lead to formation of tetrazole by diazotizing guanidine - just try to draw it to see that this kind of transformation is kind of magic stuff. To clarify nature of product try to identify it, measure a melting point - 5-ATZ decomposes without explosion at ~202-204C, try reaction with copper sulfate/sodium acetate solution 5-ATZ should form green precipitate insoluble in acetic and soluble in hydrochloric acid, closely photograph the crystals - 5-ATZ has a characteristic crystal shape.

diazoguanidine freebase reportedly stable ?

Rosco Bodine - 13-7-2011 at 18:26

Yes it is interesting and I am not following and understanding the reaction as shown by Williams because the reaction is not shown as a balanced equation.
That leaves much to the imagination about mechanism for the reaction.

For possible insight attached is the entire cyanamide related chapter from the first edition of Williams circa 1915 and the
material of interest here would be pdf page 12, original page 27 half way down the page. But here Williams is speaking
about aminoguanidine as the starting material, not guanidine. Here it seems likely that Williams is misidentifying
a freebase diazoguanidine half hydrate or perhaps a diazoguanidine hydroxide base and this is interesting also because of the description of the substance being isolated
as a crystalline material having some stability. Other references have stated flatly that diazoguanidine is unstable to the extreme that it can only be isolated in stable form as its salts. According to Williams description the guanyl azide freebase has reasonable stability and is isolatable .....so what information on this matter is correct and reliable ?

Looking further at the 1915 Williams article, it appears that what Williams identifies as being Carbamide Imidazide is
actually diazoguanidine or guanyl azide as is more usually
described. A contemporary of Williams, in 1916 von Richter
describes the Carbamide Imidazide as forming a crystalline nitrate m.p.129 which is the melting point of guanyl azide nitrate. This m.p.129 is also given in other sources including an article attached in my earlier post this page above.

Attachment: Chapter 2 Williams first edition 1915.pdf (1.3MB)
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[Edited on 14-7-2011 by Rosco Bodine]

Boffis - 14-7-2011 at 05:11

You are both right, as I mention in my earlier posts the equation given by Williams is difficult to reconcile and balance that is why I chose to investigate it. Unfortunately I often work away for long periods and so don’t have access to my laboratory. I am currently away and will not be home until early September.

If you want I will scan my copy of Williams 1948 and post it to the site library if you don’t think that will violate any copyright.

Going back to the Williams reaction when I tried to balance the equation the problem I encountered was that I needed 2 electron and 2 hydrogen atoms. There are only two possible reactant either nitrous acid or guanidine. If nitrous acid provided them then it would be oxidized to nitric acid and hydrogen but this does not sound plausible. That leaves only guanidine not really a well known reducing agent and this is where my equations become difficult to balance.

A few remarks worth making here;

Diazoguanidine as used by Williams is not an isomer of aminotetrazole nor is it synonymous with guanylazide. Look carefully at his first stage of the reaction; HONO condenses with an amino group on guanidine in a fashion analogous to say aniline producing a diazo group attached directly to the central carbon; the product is the CN4H3+ ion. The question is then how does this react with a second molecule of nitrous acid? In my initial scheme a transient tetra-azo compound is produced that absorbs 2 electron to undergo ring closure to a dehydro iminotetrazole (see attached scan scn_1). This is then reduced with 2 hydrogens to aminotetrazole. I just can’t see how guanidine can supply the electrons and the hydrogen even though nitrogen is evolved from the reaction mixture.

There are several possible source of nitrogen, one obvious reaction is a reaction between guanidine and nitrous acid analogous to that between urea and nitrous acid or perhaps more likely was that urea is being produced as a by product and this then reacted with the excess nitrous acid. I original though that this indicated that urea was a by-product (hence the attempted equation at the bottom of the page on scn_1). This looked reasonable since if some of the guanidine was being consumed as a reducing agent with the production urea there would be a large excess of nitrous acid given the ratios I had used. This is why in some of the earlier experiments I added sodium sulphite as an alternative reducing agent to hopefully improve the yield. In practice I got no yield at all!

However, just recently I have thought of another possibility, the evolution of nitrogen is reminiscent of diazo coupling or degradation. Suppose the first formed diazo compound couples immediately with a second molecule of guanidine to produce say a diguanyltriazine or diazoaminodiguanyl this then reacts with a second molecule of nitrous acid to give a transient diazodiguanyltriazine which then rearranges into aminotetrazole, formic acid and ammonia with the liberation of nitrogen (see scan scn_2). This mechanism appeals to me because it explains why the reaction works with only half the theoretical amount of acid and it overcomes most of the problems described above, except one.

The large excess of sodium nitrite I used (given that half the guanidine is converted into by-products) should have converted the aminotetrazole into a diazo compound and I would have either got 5,5 diazoaminoditetrazole or an explosion. A small amount of a bright yellow explosive compound is produced but not nearly enough to account for the excess nitrite which is twice that required to diazotize all of the amino tetrazole.

It should be possible to test the various possibilities by reducing the excess of sodium nitrite to get the same or better yield by reducing side reaction and by looking for formate ions in the residue.

Furthermore it may be possible to isolate the intermediate linear triazine by reducing the sodium nitrite to one quarter of that originally used. I clearly have a lot of avenues to explore next time I home.

There is of course the possibility that the products do not contain 5-aminotetrazole. The second crop is clearly a complex mixture of salt, a fine yellow powdery compound and coarser colourless blades. I’ll get back to you in September!

Scans of equation scheme:


Attachment: scn_1.pdf (74kB)
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Attachment: scn_2.pdf (63kB)
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[Edited on 14-7-2011 by Boffis]

Rosco Bodine - 14-7-2011 at 07:58

You may also try working with the nitrate instead of the chloride to see if there is any benefit in the reaction or isolation.

Engager - 15-7-2011 at 14:36



[Edited on 16-7-2011 by Engager]

tetrazole.jpg - 124kB

Boffis - 16-7-2011 at 00:46

I work with the chloride because I have a lots of it and it a pain to convert it to the nitrate. There is also the point that the by-product sodium chloride has a very flat solubility/temperature curve and so tends not to crystallize out with falling temperature and also tends to salt-out less dissociated compounds. I have converted some to the nitrate to prepare nitroguanidine but its a tricky process via alkali nitrates so I use silver nitrate. The silver is easy to recover from the precipitated silver chloride and recycled but its easier for these reaction to work with the chloride directly.

Whats with the secret picture? If it large just turn it into a pdf and attach.

Rosco Bodine - 16-7-2011 at 02:18

Perhaps the diazotization of guanidine proceeds through formation of a bis compound similar to the azobisformamidine gotten when aminoguanidine is oxidized by KMnO4. You seem to be looking at something along that line
in your drawn reactions in the second scan. I am not sure but the intermediate
could be something like a bisguanylhydroxylamine if that is possible.

Actually these reactions are a bit mysterious and I find myself reading along to a point where I think I have been following it and then realize the dots aren't really connecting somehow. It is intriguing huh. This one definitely needs more work.

Identification of the presumed but unconfirmed 5-aminotetrazole may be convenient by the nitrate which should melt at 174-175 with decomposition and possibly deflagration. For a quantitative ident by titration possibly the picrate ? These are off the top of my head so no references. I know the guanyl azide isomer forms a picrate.

[Edited on 16-7-2011 by Rosco Bodine]

AndersHoveland - 16-7-2011 at 13:33

This article may shed some light on the mystery:
http://pubs.acs.org/doi/abs/10.1021/j150327a017


"Nitroaminoguanidine, NH2NHC(=NH)NHNO2, on diazotization yields nitroguanidine and nitroguanyl-azide which may be isomerized to 5-nitramine-tetrazole. Nitroguanyl azide acts as a dibasic acid when titrated with alkalis, as it is quantitatively isomerized to the dibasic nitramine-tetrazole."
http://onlinelibrary.wiley.com/doi/10.1002/jctb.5000681101/a...

Nitroguanyl-azide would have the structure
[-]N=N[+]=NC(=NH)NHNO2
"Nitramine-tetrazole" refers to a compound with the structure
(N4H2C)=NNO2
*note that "nitramines" of tetrazoles exist as a more stable tautomer which actually consists of nitrimino groups instead, with two hydrogens attached to nitrogen atoms in the ring.

Of course, nitrous acid will not necessarily readily diazotize a guanyl group just because the two regents are reacted;
“Acetamidine nitrite, CH3C(=NH)NH2*HONO prepared by treating concentrated aqueous solution of acetamidine hydrochloride with silver nitrite, melts at 148C with decomposition, and is soluble in water and alcohol, but insoluble in ether.”

One would be inclined to think that diazotization of a guanyl group would simply change the amino group into a diazonium salt.
R--C(=NH)NH2 --> R--C(=NH)--N[+]ΞN

(C6H5)C(=NH)N=NOH is likely capable of forming a potassium salt, and this could be a possible candidate for the supposed/ mysterious "dioxy-tetrazotic acid", but if this is the case, it is not entirely clear how this would be reduced by sodium amalgam to the tetrazole.

[Edited on 16-7-2011 by AndersHoveland]

Rosco Bodine - 16-7-2011 at 19:41

Actually I was looking at both abstracts related to guanidine reaction with nitrous acid early this morning.

The diazotization of nitroaminoguanidine comparison somewhat brings us full circle back to the last few posts near the end of page one of this interesting thread.

Here attached are the three references of recent mention and interest. Thanks to solo.

Attachment: Diazotization of nitroaminoguanidine.pdf (624kB)
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Attachment: Guanidine and Nitrous Acid. I.pdf (548kB)
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Attachment: Guanidine and Nitrous Acid. II.pdf (1.1MB)
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[Edited on 17-7-2011 by Rosco Bodine]

AndersHoveland - 16-7-2011 at 23:41

So it would seem the question is far from settled, as the investigative techniques available at the time of publication were very limited, and the conclusions are ambiguous. The paper mentions nothing that would correspond to the "dioxy-tetrazotic acid" mentioned in the other paper by Lossen.

[Edited on 17-7-2011 by AndersHoveland]

Boffis - 17-7-2011 at 09:56

Thanks for all the information guys. I have spent most of the afternoon reading them and it's going to take me a day or so to crystallize my thoughts but looking at some of the information I can see several problems.

Engagers data highlight the problem I had foreseen; the need for reducing action. In the example Engager posted they used sodium amalgam but in my reaction mixture there was nothing that could match this in terms of reducing ability.

In my experiments I quickly discovered that you need to carry out the reactions at 0 - 5C or you simply get lots of nitrogen evolved much as Bancroft and Beldon observed, they do not really sound to have controlled the reaction temperature and so I presume it took place at room temperature. At the lower temperatures I used the reaction is slow and very little nitrogen is evolved if the acid is added slowly with cooling. The bright yellow solution and precipatate also suggests that the reaction is more complex than they give it credit!

It looks like the product I have got is probably either cyanamide or more likely, given its tendency to dimerize, dicyandiamide. Either way I have plenty material to work on and I can easily test the products. All I need is time!

By the way can any of you guys with access to a library or on line access get:
Buchanon; Ind. Eng. Chem 15, p637 1923
This is one of the references on the Bancroft papers re quantitative tests for the various compounds.

AndersHoveland - 17-7-2011 at 14:34

Thioruea dioxide might be a better reducing agent, instead of the sodium amalgam. I suspect it would greatly increase yields, for although it is a poweful reducing agent, it would be more selective than elemental sodium, and I suspect that transient tetrazoles formed in solution are rapidly degraded by the Na.
http://www.sciencemadness.org/talk/viewthread.php?tid=11785

Rosco Bodine - 17-7-2011 at 21:39

What I would speculate about this reaction scheme involving nitrosation of guanidine to produce cyanamide in high yield is that it should be possible to then proceed further using hydrazine sulfate to form aminoguanidine in situ followed by a second stage nitrosation to form the guanyl azide, either isolatable as a salt or further cyclized at modified pH to
5-aminotetrazole. Basically the value of nitrosation of guanidine may prove most useful as a means of obtaining cyanamide under mild conditions, the cyanamide then being useful for all the subsequent uses for which cyanamide is a precursor. In that regard, then the nitrosation of guanidine to cyanamide is certainly an interesting and useful item to have available in a chemists cyanogen chemistry toolkit.

This approach to a production of aminoguanidine using hydrazine sulfate and cyanamide gotten by a method
not requiring pyrolytic method may prove to be less complicated than the method using cyanamide gotten by pyrolysis
and subsequently reacted with hydrazine sulfate. A conversion of guanidine nitrate to nitroguanidine which is then reduced to aminoguanidine is also avoided by a strategy which is a hybrid method drawing aspects from both of the known routes to aminoguanidine. As nitrosation of the aminoguanidine is required in the further conversion of the aminoguanidine
for aminoguanidine gotten from either a hydrazine or a non-hydrazine route, and given that the synthesis of hydrazine is lower complexity than a pyrolyitic method for cyanamide, or the synthesis and reduction of nitroguanidine, from a process complexity standpoint, it would seem simpler to use a hybrid method using hydrazine with a two stage nitrosation which eliminates both a pyrolytic method or alternative reduction, either of which is followed anyway by one nitrosation.

When details are worked out for this speculated alternative route it may well prove to be the simplest and most direct route to guanyl azide, or 5-aminotetrazole, or stopping reaction at earlier stage an easy source for cyanamide or cyanoguanidine. Nitrosation of guanidine could be a very versatile synthetic method.

@ Boffis, This is potentially a very nice find if this works out as an alternative mild condition method for cyanamide and hybrid hydrazine method for aminoguanidine derivatives gotten by nitrosation of guanidine. What I am speculating
here does seem more technically plausible ....yes?

[Edited on 18-7-2011 by Rosco Bodine]

Engager - 18-7-2011 at 09:00

Here are some more refs that may be interesting for tetrazole topic. First 3 refs describe some interesting aspects of 5-ATZ complexing behavior, complex witch is precipitated in qualitative test for 5-ATZ is one of compounds described in this references. Ref 4 is general review of tetrazole chemistry and may be interesting for digging ref. links about many tetrazole compounds and their chemistry. Ref 5 contains synth procedures for some interesting 5-substituted tetrazoles by Schtolle (on German).

Attachment: Complexes of Copper(II) and Some 5-Substituted Tetrazoles.pdf (169kB)
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Attachment: Metal Tetrazole Complexes Bis-(5-aminotetrazolato)-copper(II).pdf (147kB)
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Attachment: Complexes of Iron(II) and Some 5-Substituted Tetrazoles.pdf (145kB)
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Attachment: Chem.Rew-41-1-The Chemistry of the Tetrazoles..pdf (634kB)
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Attachment: Ber-62-Schtolle-1118-1126(ATZ,OTZ,TZ,ClTz,BrTz,ITz).pdf (634kB)
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I have tons of references about tetrazoles, i can place them in this topic if somebody interested. :)

[Edited on 18-7-2011 by Engager]

Rosco Bodine - 18-7-2011 at 15:35

Surely you must be intrigued by the idea of using urea as a precursor for two different intermediates for 5-aminotetrazole via relatively mild reaction conditions.
Urea is converted to hydrazine sulfate. A second portion of urea is converted to a guanidine salt such as guanidine nitrate using the silica gel catalyzed reaction with ammonium nitrate. The guanidine nitrate is nitrosated via sodium nitrite to form a cyanamide solution which is reacted with the hydrazine sulfate to from aminoguanidine. The aminoguanidine is nitrosated to guanyl azide and cyclized
to 5-aminotetrazole. This may be the easiest pathway yet for having low technical demands for equipment and simple precursors. I think Boffis has experimented with an easy route to cyanamide from urea by way of guanidine, and this can be exploited as described....although all the reaction details are not yet thought out, still this would seem to be very feasible as a reaction scheme. This scheme should be more specific for monoaminoguanidine than the probable mixture of monoaminoguanidine and diaminoguanidine and triaminoguanidine as may be gotten from reaction of hydrazine directly with the guanidine. Which of these two different reaction schemes may prove better is unknown.


[Edited on 18-7-2011 by Rosco Bodine]

Rosco Bodine - 20-7-2011 at 00:14

@Boffis Please tell us, does your crystalline product obtained from the nitrosation of guanidine melt at about 44C ?

If your product is indeed cyanamide then this is a very useful reaction which
you have found and called to our attention.

There is another reaction which I found which may be of interest regarding guanidine. Reportedly guanidine nitrate
in sodium acetate solution can be reacted with sodium hypochlorite to produce chloroazodine also called azochloramide or azobischloroformamidine. Possibly this may also have some interest as an intermediate.
http://www.chemspider.com/Chemical-Structure.4880329.html
alternate structure
http://www.chemspider.com/Chemical-Structure.9985.html

[Edited on 20-7-2011 by Rosco Bodine]

Boffis - 24-7-2011 at 09:34

@Engager I'd love to see anything you have on tetrazole, triazole and pyrazole! My interest in these compounds goes way beyond simply things that go bang! My interest is in their ability to form well crystallised metal salts and complexes eg picrolonic acid and violuric acid.

@Rosco I haven't characterised the products of the reaction yet but I did try to recrystallize a little of the first crop of crystals, they dissolved slowly but completely but the water boiled before they had dissolved and the remaining solid did not melt, hence the melting point is >100C. Also most of the material crystallized on cooling and cyanamide is very soluble (about 85gm/ 100ml of water at room temp) only a little would have crystallized. Dicyandiamide melts at >200C and is much less soluble in cold water (4.3gm/100ml) so this is a possibility but the crystal shape is much more in keeping with aminotetrazole. After much consideration and reading I think that it is possible that Williams is correct and that 5 aminotetrazole may be prepared directly from guanidine and nitrous acid in a single "one pot" synthesis.

I will post as an attachment in the next day or so my full argument. Where I think Williams was wrong is that he saw this as an incremental reaction of nitrous acid with amine groups on the same molecule of guanidine were as I now believe that it is a bi-molecular condensation to produce a transient triazene that then de-arranges to aminotetrazole and a smaller fragment such as formamidine or such like.

It is now clear to me that in my original experiments I used far too much sodium nitrite and that this probably destroyed much of the product via unstable diazo compound formation and accounts for the poor yield. However, if I'm right about the bi-molecular nature of the reaction the maximum yield will only ever be 50% from the guanidine. It should be possible to test this theory once I am back in my lab!

As I said I post my full thoughts shortly; they're too long with too many insertions to post peace meal!

Engager - 24-7-2011 at 11:15

I've got some time to read your posts more carefully, apparently your 5-aminotetrazole is a big mistake. There is no way in hell guanidine can form it in such manner. Product your produced is likely to be nitrosoguanidine, mixed with come cyanamide/urea derivatives.



1. Guanidine reacts with nitrous acid to form nitrosoguanidine as first reaction product.

NH2-C(=NH)-NH2 + HNO2 => NH2-C(=NH)-NH-NO + H2O

2. Diazoguanidine is quite unstable and can easily decompose forming cyanamide, water and nitrogen gas:

NH2-C(=NH)-NH-NO => NH2CN + N2 + H2O

3. Cyanamide is highly reactive and is unstable in acidic environment an is quickly hydrolized forming urea:

NH2CN + H2O => NH2-CO-NH2

4. Urea forms salts with acids, many of them are slightly soluble in acids. Nitrate can be example:



5. Nitrosoguanidine is nasty mutagen so you are welcomed to party.

6. If you think, that you got low yield due to the diazotation of 5-ATZ, you are terribly wrong. Even if process you proposed somehow produced 5-ATZ, first drops of more nitrite (to form more nitrous acid) will form diazotetrazole, witch is extremely nasty and unstable explosive witch detonates IN SOLUTION even at 0C without any external stimulus, it can expode even in drops of 5-ATZ solution then drop falls to the flask evolving nitrogen oxides. I personally grantee you that diazotizing tetrazole is kind of experience that you won't soon forget.

nitrosoguan.jpg - 265kB

[Edited on 24-7-2011 by Engager]

Rosco Bodine - 24-7-2011 at 17:24

If nitrosoguanidine does form via nitrosation of guanidine, then it is worth noting that nitrosoguanidine may be reduced to aminoguanidine just as nitroguanidine may be reduced to aminoguanidine, and indeed nitrosoguanidine is an intermediate reduction product during the reduction of nitroguanidine to aminoguanidine. Personally I would place confidence in the Cornell study of Bancroft and Belden identifying cyanamide as the nitrosation product of guanidine, however it is known that cyanamide is pH and temperature and
time sensitive, so if the conditions are not carefully controlled it is probable that
dimerization of the cyanamide to cyanoguanidine would occur. Something useful can probably be done with this scheme of nitrosation of guanidine to produce a number of different products depending upon the reaction conditions . This definitely would make some interesting experiments.

Boffis - 24-7-2011 at 20:55

Hi Guys,

I have already considered these reactions and there are numerous possibilities. I have already considered the nitrosoguanidine reaction (see the attached pdf of my "thinking document") and I believe the trace contaminant of yellow material in the first crop of crystals to be nitrosoguanidine. I also discuss the possible nitroso compound + amine compound = azo compound. This could lead to a triazene that may de-arrange to aminotetrazole; several such de-arrangements have already been published and I have quoted examples.

Take a look at the attached document and have a go at some of the reactions. And please, I found the claim in Williams book difficult to believe too at first, but as I investigate these reactions it is becoming clear that the chemsitry of urea and guanidines is very complex and very sensitive to conditions. So simply quoting an equation is meaningless without giving the conditions. I am very aware that I have not proved the identity of the product of my reactions but equally I can assure you that cyanamide and urea are not important componenets of the first crop of crystals, cyanamide is too soluble and urea too sensitive to nitrite. After boil down, the second crop of crystals could contain almost anything; cyanoguanidine, melamine etc but a yellow contaminant is still present.

When I am home next I will try preparing nitrosoguanidine by both routes and then try reacting it with guanidine to see if I can isolate the triazene and then make it de-arrange to aminotetrazole. As a say in my document I don't see these reactions as a route to cyanamide particularly but almost any N-N bearing product would be a potential precursor to the tetrazole.

Attachment: My thoughts on the guanidine-nitrous acid reaction.pdf (550kB)
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Rosco Bodine - 25-7-2011 at 00:19

It appears you probably have the makings of a good journal submission going right here in this thread and with your paper. These reactions generally are critically sensitive to pH and temperature and other conditions, which can result in three or more ultimate products as the main yield, depending upon what are the conditions. The nitrosation of aminoguanidine is a perfect example where neutral condition produces tetracene as a guanyl nitrosoaminoguanyltetrazene product, acidic condition produces guanyl azide, and a pH buffered with sodium acetate / acetic acid, leads to a bis tetrazole structure diazoaminotetrazole. Cyanamide and cyanoguanidine are also subject to the same steering in their reactions by pH and this has also been observed in the hydrazine and azide routes. Indeed also the guanyl azide is governed greatly by pH in the course of its reactions as is its precursor aminoguanidine. It wouldn't be any surprise if a buffered reaction system will be of use in some of these reactions intending a specific path and end product, maybe a sodium acetate - acetic acid buffer or perhaps a boric acid - sodium borate buffer, during the nitrosation to limit the reaction pH. I am still trying to understand these interesting reaction schemes which evidently are profoundly affected by relatively subtle differences in reaction conditions. There's plenty unanswered about mechanisms here to try to wrap ones head around and it is definitely interesting to dredge up something like this from antiquity and take a deeper look. Interesting paper. I hope you continue investigating this.

[Edited on 25-7-2011 by Rosco Bodine]

Boffis - 25-7-2011 at 01:40

I certainly intend to continue this investigation whatever the products are simply because I am so intriged by the scope to vary the outcome with subtle changes to conditions. I must admit we need much better control of pH and next time I will monitor pH as well as trying various buffers. I also intend to run two sets of experiments with 1/4 and 1/2 the amount of sodium nitrite I used before to see how this affects the products. I further intend to develop the qualitative tests referred to by Bancroft but the silver nitrate test for cyanamide isn't very useful because I'm using chorides and hydrochloric acid.

I will also try repeating Bancroft's experiments and see if I can isolate the cyanamide.

@Engager You're right clearly no diazotization of aminotetrazole since 30mins boiling down didn't provoke an explosion! However, most of the intermediates and possible products are sensitive to nitrous acid or nitrites so the vast excess of sodium nitrite I used is likely to have reduced the yield of any product and generated much nitrogen instead.

Rosco Bodine - 25-7-2011 at 02:34

Engager has a pretty good branched tree diagram of known reactions, but there
are some variations and branches which could be added as we discover them.
Another note should be made that nitrosoguanidine reacts readily with hydrazine to form aminoguanidine. I think aminoguanidine bicarbonate and probably tetracene as well are kind of waypoint intermediates to be kept in mind because of their low solubility, so any opportunity where a low solubility intermediate can be gotten to drop out of solution from even a dilute reaction mixture can be exploited, if only as an identifier test for presence of the components that would lead to those two. I am thinking the same thing with regards to the hydrazine, because of its known reactions it may be helpful in mapping these nitrosation reactions to identify what may be the unknown product.

With regards to Bancroft's experiment it isn't the isolation of the cyanamide that would be most interesting, but to operate on the presumption it is present and then react it with hydrazine sulfate or hydrazine nitrate to form the aminoguanidine which could be precipitated as bicarbonate
by adding sodium bicarb. Or perhaps not even bother with
isolating the bicarbonate of aminoguanidine but then further proceed on the presumption it has formed and continue the nitrosation to produce guanyl azide. What I am thinking is
a one pot synthesis from guanidine to 5-aminotetrazole,
as a bit more complicated than the Williams procedure, but following a course of more clearly identified reactions. Order of addition could be very critical for example it may be necessary that the cyano product be added to the hydrazine component so the hydrazine appears in excess, or it may require simultaneous addition so that neither cyano component nor hydrazine component is in excess ....nothing can be taken for granted with fickle reactions that may not go at all with the dump in a lump methods, or that may be the only way they go....such are the unknowns.

I have a different somewhat general related idea, since triaminoguanidine is another product easily gotten as a result of reactions of hydrazine with guanidine or cyanamide or cyanoguanidine, and while the energetic triaminoguanidine salts are of already known value, it would seem possible that other interesting products might be gotten by nitrosation of triaminoguanidine. Tetrazoly azide and by further reduction for 5-aminotetrazole, both products are obtainable via nitrosation of diaminoguanidine, so the same or closely related materials may be gotten similarly from triaminoguanidine.

[Edited on 25-7-2011 by Rosco Bodine]

Engager - 26-7-2011 at 15:48

Quote: Originally posted by Rosco Bodine  
This is being posted here as nitrotetrazolate related hypothetical material even though the same post is being duplicated in another older thread as a followup there.

http://www.sciencemadness.org/talk/viewthread.php?tid=10969#...

Guanyl Azide may possibly form an interesting salt with 3,5-dinitro-1,2,4-triazole. I am uncertain how it may be done, but speculate it may be possible to first form the aminoguanidine salt of 3,5-dinitro-1,2,4-triazole as an
intermediate.

Attached are some references. Guanazole would be gotten from Dicyandiamide reaction with hydrazine as per US2648671. Hydrazine Sulfate could be converted to the Hydrazine Dihydrochloride via Calcium Chloride and filtering.

Guanazole (DAT) is diazotized to 3,5-dinitro-1,2,4-triazole as per the method described on page 13 of the Los Alamos technical report attached.

The DNT is neutralized with aminoguanidine bicarbonate or
a double decomposition of perhaps a soluble sodium DNT salt with a soluble aminoguanidine salt perhaps the nitrate,
may work.

Then the aminoguanidine 3,5-dinitro-1,2,4-triazole is converted to the azidoformamidinium 3,5-dinitro-1,2,4-triazole per the method used for conversion of aminoguanidine perchlorate to azidoformamidinium perchlorate. See Klapotke paper attached, regarding compound 4 page 3.

No search has been done for the speculated compound
azidoformamidinium 3,5-dinitro-1,2,4-triazole ....
existence and properties at this point unknown.

Perhaps this could be a "green primary" class material
or a candidate for investigation.

[Edited on 15-6-2011 by Rosco Bodine]


Synthesis of guanazole is not that easy, especially the separation part. I've actually tried process proposed by the patent but with no luck since it's much more complicated then one can think. First thing that there is no simple way one can observe reaction taking place without some expensive lab analytical equipment. No gasses are formed, no color changes, no visible pH change, so you can't conclude that reaction is actually taking place. Second thing is that product must be separated from ammonium chloride, patent suggest remove solvent in vacuum (since guanazole is oxidized by the air) and then extract several times with hot methanol, this requires some complicated glassware setup for vacuo and use of methanol witch is quite toxic and is actually banned chemical in many countries so one can not obtain it without difficulty.

Now on conversion of guanazole to dinitrotriazole. Again process is not that simple, process produce mixture of dinitrotriazole and 5-nitrotetrazole in aproximately 50/50 quantity with elimination of some CO2. So one will also need to separate this bodies. Salts of dinitrotriazole have not been well studied even as simple ones as sodium or potassium, only salt of DNT witch is found to be insoluble was silver one. This may give some idea how to separate 5-NTZ from DNT (for example one can try to precipitate 5-NTZ with some copper salt), however taking to account that salts are not well studied you can not assume will or not DNT be precipitated by copper as well. So significant effort is reqired for separating this bodies. One more problem is that reaction intermediates tend to precipitate during diazotizing process what also leads to some potentialy hazardous situation during this synthesis.

Only way known to produce pure DNT is to use guanazine instead of guanazole. But preparation of guanazine is hell, it is very very difficult and involves some nasty/dangerous chemicals and is actually even harder then separation of 5-NTZ from DNT. Known routes of synthesis are action of cyanogen chloride on hydrazine, desulfurising thiosemicarbazide with mercuric oxide, and removing solvent in vacuo since guanazine is very readily oxidized on the air. I've made attempt to prepare it in this manner some long time ago and can say that this reaction is also hell, very toxic, huge amount of HgO is reqired to produce even grams of product.... This one is practically unrealistic.

Summarizing statements above it is clear how hard it would be to prepare DNT, in my opinion that is much much harder then prepare 5-nitrotetrazole instead.

Attachment: US3054800.pdf (130kB)
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[Edited on 27-7-2011 by Engager]

Attachment: Synthesis of guanazine.pdf (245kB)
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AndersHoveland - 26-7-2011 at 16:57

Can 3,5-dinitro-1,2,4-triazole (DNT) not simply be prepared by nitration of 1,2,4-triazole?

[Edited on 27-7-2011 by AndersHoveland]

Engager - 26-7-2011 at 17:11

No. Direct introduction of nitro group is not possible, since nitrogen hetero atoms in the ring deactivate it toward electrophilic substitution. Literature references state that all attempts to nitrate 1,2,4-triazole directly were unsuccessful.

Rosco Bodine - 26-7-2011 at 17:27

The reaction of cyanoguanidine with hydrazine reportedly is exothermic and complete, producing virtually a quantitative yield, so any problem would be with isolation of the guanazole from the ammonium byproduct salt corresponding
with the acid which was the hydrazine salt. Really it is only the ammonia which needs to be eliminated, possibly by boiling after basification to midpoint using sodium hydroxide which hopefully could free the ammonia as a volatile and
leave the guanazole hydrochloride intact. The equimolar sodium chloride byproduct would only be a spectator impurity and would not interfere with subsequent nitrosation.

Guanazole perchlorate might be of interest itself.

With regards to the byproduct 5-nitrotetrazole, I had also seen that reported
in the patent process but had missed it being an issue mentioned in the Los Alamos paper so that remains an unanswered question. I'll read more on this
and be thinking about it. There is possibly a better way of doing this.

AndersHoveland - 26-7-2011 at 19:15

Quote: Originally posted by Engager  
Direct introduction of nitro group is not possible, since nitrogen hetero atoms in the ring deactivate it toward electrophilic substitution. Literature references state that all attempts to nitrate 1,2,4-triazole directly were unsuccessful.


Are you sure you are not confusing 1,2,4-triazole with 1,2,3-triazole?

In any case, there is reference in the literature to nitration of N-phenyl 1,2,4-triazole by nitronium tetrafluoroborate, and also similar references stating that 2-phenyl-1,2,3-triazole can be nitrated with mixed acids, and as the phenyl group can become nitrated into a picryl group, it hydrolyzes with water leaving nitro-1,2,3-triazole and picric acid.

Rosco Bodine - 27-7-2011 at 06:27

Guanazole is amphoteric so this may facilitate isolation if there is any intention of doing so, there is probably some metallic "guanazolate" which might have limited water solubility. Really I see no need for isolation of the guanazole intermediate.
Truthfully the byproduct ammonium salt gotten in the formation of the guanazole might be eliminated in some other way than by basifying and boiling away the volatile ammonia from the guanazole hydrochloride and sodium chloride brine.
The ammonium chloride simply being left there would not prevent the nitrosation
of the guanazole hydrochloride, but it would be decomposed to nitrogen and water by the nitrous acid which would likewise decompose that much nitrous acid simultaneously, requiring that more nitrous acid be used to make up the loss.
So it should be possible to proceed with the nitrosation of the crude guanazole hydrochloride and ammonium chloride mixture gotten from the conversion of cyanoguanidine by hydrazine dihydrochloride. With regards to the mixed product
resulting from the nitrosation being an equimolar mixture of 3,5-dinitro-1,2,4-triazole and 5-nitrotetrazole, more precisely the mixed copper salts, instead
of or in addition to any subsequent efforts at separation of these materials,
making use of the mixed product to form derived mixed salts would be a
definite interest for experiments. Double salt derivatives could have usefulness
or even advantages.

If the mixed copper salts were digested with sodium carbonate to precipitate the copper and leave a mixed solution of the sodium salts, that solution could be reacted with guanyl azide nitrate to form the mixed guanyl azide salts derivative and byproduct sodium nitrate.

azidoformamidinium 3,5-dinitro-1,2,4-triazole / azidoformamidinium 5-nitrotetrazole should result as a mixed salt

Alternately, instead of using guanyl azide nitrate, if Azobisformamidine Dinitrate were substituted,
a bridged or mixed salt of the nitro-azolic acids may result as Azobisformamidine 3,5-dinitro-1,2,4-triazole / 5-nitrotetrazole

[Edited on 27-7-2011 by Rosco Bodine]

Rosco Bodine - 28-7-2011 at 20:10

@Engager
Actually the idea of not really needing to isolate the guanazole was either me reinventing the wheel, or my being caught thinking like a Russian, because this is not a new idea at all. See attached abstract :D Perhaps you could help with that article.

Also it has become known that the diazotization of guanazole can follow three different paths leading to different products depending upon conditions particularly with regards to the excess of sodium nitrite being used and the acid evidently, so the diazotization condition may be pH related which would be no surprise.

The Los Alamos report attached here again as in the other thread where some preface discussion was or is occurring
concerning the diazotization of guanazole,
http://www.sciencemadness.org/talk/viewthread.php?tid=10969#...
is illuminating concerning the related patent also from Los Alamos for the production of the ammonium salt of DNT, US4236014 attached. The Los Alamos report of 1978 on page 10 states that the Los Alamos process was based upon a Russian method published 1970 and cites the Russian publication reference #15. The Los Alamos related patent for the ammonium salt makes reference to the same Russian publication of 1970. It is not mentioned in the Los Alamos report of 1978 or the patent applied for 1979 any sort of
dual reaction product resulting from the nitrosation of guanazole which produces 5-nitrotetrazole as when the Sandmeyer method of US3054800 (which you attached above) is followed and evidently leads to a dual product.

A third reaction route leading to yet a third reaction product, and several other by products is described by US3431251
attached.

Let no one ever think that the chemistry of these related compounds is not sensitive to conditions because certainly
the diazotization of guanazole is a good example how different reaction variables define greatly what is the product.

Whew ....I have the most intense sensation of deja vu as I type this post. So I hope I am not repeating myself for having lost track of having posted this same thing before.

The inference is clear that guanidine could be used as the starting material and via nitrosation converted to cyanoguanidine, further reacted with hydrazine sulfate to form guanazole and subsequently by nitrosation again
could be obtained DNT.

Attachment: rjapchem0839_abstract.pdf (3kB)
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Attachment: US3431251 Diazotization of Guanazole Polymer Product.pdf (105kB)
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Attachment: US4236014_Production_of_the_ammonium_salt.pdf (157kB)
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Attachment: Diazotization of Guanazole to Dinitro Triazole 00312939.pdf (1.2MB)
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[Edited on 29-7-2011 by Rosco Bodine]

Rosco Bodine - 28-7-2011 at 22:10

Quote: Originally posted by Engager  
I've got some time to read your posts more carefully, apparently your 5-aminotetrazole is a big mistake. There is no way in hell guanidine can form it in such manner. Product your produced is likely to be nitrosoguanidine, mixed with come cyanamide/urea derivatives.



1. Guanidine reacts with nitrous acid to form nitrosoguanidine as first reaction product.

NH2-C(=NH)-NH2 + HNO2 => NH2-C(=NH)-NH-NO + H2O


Above I made note that nitrosoguanidine can be reduced to aminoguanidine and is in fact an intermediate reduction product when nitroguanidine is reduced to aminoguanidine.
Of interest also is that nitrosoguanidine readily reacts with hydrazine to form aminoguanidine. It is known also that
subsequent further reaction with additional hydrazine can lead to formation of diaminoguanidine and triaminoguanidine
as the second and yet a third hydrazine react with what
was or may be originally guanidine .....not necessarily having nitrosoguanidine as a starting point. Attached is a single relevant page from the Lieber and Smith article attached in complete form earlier in this thread. Anyway, it is clear that some parallel pathways are possible in these complex and intriguing reactions. So let us not be too hasty to rule out alternative paths or possible reactions which may be an easier way of synthesis for a desired product. Indeed there is sometimes more than one way to skin a cat. Different conditions for reactions can easily lead through different paths to different products. I think it was Tenney Davis who originated that observation about nitrosoguanidine being produced by nitrosation of guanidine, and yet there is the different report from Cornell by Bancroft and Belden identifying Cyanamide as the product ....so who is correct?
The answer is that both reports could be accurate if the reaction conditions were different and each reported accurately what was gotten for their particular work.
So the devil is in the details :D With hydrazine inserted
into the reaction in the proper place it can be made to work
in either case, more surely. So this is not a loss even if the
original report of Williams is incorrect or turns out to be a misprint not caught by the editors. It would not be the first time if the Williams described reaction is indeed a misprint.
I have actually thought it may be aminoguanidine which Williams meant to write as the word where the textbook says guanidine. And a simple misprint may be the cause of this confusion which has certainly been of some benefit for causing lively debate and investigation. We have identified errors in print before and this may be another one....or maybe not :D

Attachment: Page from The Chemistry of Aminoguanidine and Related Substances Lieber and Smith.pdf (21kB)
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In a post above I failed to post a reference and it is too late to edit and attach it to that earlier post so here attached
is the nitrosation of diaminoguanidine to produce tetrazolyl azide or the "tetrazylazide" referenced on page 1 of this thread, supporting further curiosity about what may result
as a product for nitrosation of triaminoguanidine, which is more easily isolated than the diaminoguanidine.
Quote: Originally posted by Rosco Bodine  
I have a different somewhat general related idea, since triaminoguanidine is another product easily gotten as a result of reactions of hydrazine with guanidine or cyanamide or cyanoguanidine, and while the energetic triaminoguanidine salts are of already known value, it would seem possible that other interesting products might be gotten by nitrosation of triaminoguanidine. Tetrazoly azide and by further reduction for 5-aminotetrazole, both products are obtainable via nitrosation of diaminoguanidine, so the same or closely related materials may be gotten similarly from triaminoguanidine.


Attachment: The Reaction of Nitrous Acid with Diaminoguanidine in Acetic Acid Media. Isolation and Structure Proof of Reaction Produ (672kB)
This file has been downloaded 904 times

Of course it should be kept in mind that depending upon conditions the nitrosation of diaminoguanidine or triaminoguanidine would each be likely to follow three distinct reaction paths to three differing products as well.

Somewhere along this analysis is where every good chemist
is likely to say out loud... Jesus, Joseph, and Mary ! :D

( I am having great fun with this )

[Edited on 29-7-2011 by Rosco Bodine]

Boffis - 31-7-2011 at 23:30

I can't believe Williams comments were and accident or missprint. There is too much detail given elaborated with formula. He cites no reference though so we can only assume that it was his own observation. I thing he probably carried out a quick experiment under poorly constrained conditions and obtained a little amidotetrazole and never followed it up.

The paper on diaminoguanidine seems to highlight yet again the sensitivity of the reaction with nitrous acid to reaction conditions. In an earlier post there is a reference to the production of 1,5 diamonotetrazole via the same reaction but only over a very narrow pH range. What is so curious about this reaction is that one mole of sodium nitrite doesn't seem to react or the reaction in reversible.

There's clearly a lot of work to do on the reaction of nitrous acid with guanidine group compounds and I am frustratingly remote from my lab!

Rosco Bodine - 1-8-2011 at 09:34

It is not so difficult for me to follow the simpler reactions proceeding with hydrazine, but the alternate "magic" route of Williams seems less likely and more complex. I still see the convenience for some of these reactions as alternative
laboratory methods which exploit the use of urea as a starting material, catalytically convertible to guanidine at only moderately elevated temperature using silica gel and an ammonium salt. For hydrazine sulfate also urea is a starting point, and reportedly by a modified method semicarbazide can be gotten from urea.

Guanidine nitrate can be dehydrated to ntroguanidine via H2SO4 and reacted with hydrazine to form nitroaminoguanidine, which may be nitrosated to nitroguanyl azide and cyclized to nitroaminotetrazole as per description on page 1 of this thread.

Alternately nitroguanidine reportedly can be reduced quantitatively to nitrosoguanidine via electrolysis over a mercury cathode in a divided cell using nickel sulfate to complex the nitrosoguanidine as it forms, and subsequently the nitrosoguanidine may be reacted with hydrazine to form aminoguanidine. It is anticipated this process industrially may be a cost efficient route and not produce the unrecyclable sludges and difficulties or costs of alternative methods. See US2835631 attached.

Evidently guanidine can be nitrosated to cyanamide or further dimerized to cyanoguanidine, then reacted with hydrazine dihydrochloride to form guanazole,
which may be nitrosated to 3,5-dinitro-1,2,4-triazole, or via Sandmeyer to a mixed product 3,5-dinitro-1,2,4-triazole / 5-nitrotetrazole.

And of course if there is a way to react the cyanamide of Bancroft and Belden with hydrazine, then all of the well known reactions which can be done from there are
available, with the need for a pyrolytic process for cyanamide having been eliminated.

There is nothing I can find about the reaction of nitrous acid with triaminoguanidine. Will the triaminoguanidine simply decompose in reaction with nitrous acid or is there more probably produced a tetrazolyl azide related analogue product gotten as would be expected from observing the reaction of nitrous acid with diaminoguanidine which produces tetrazolyl azide?

Having read further references I would amend and correct my statements speculating early in this thread about the troublesome instability of guanyl azide and nitroguanyl azide, as it has been clearly reported that both materials are isolatable and relatively stable.

The "amidoguanidine diazohydroxide" material which Williams identifies as produced by the reaction of aminoguanidine and nitrous acid at 0 C is probably tetracene.

I still suspect that there is a misprint in the Williams book which involves the guanidine, should be aminoguanidine, the math doesn't work the way Williams is showing one too many nitrogens from the first reaction from guanidine, but if it was starting from aminoguanidine then the five nitrogens would be possible and the first equation would balance.
It would also seem possible that Williams is referencing a rather extreme condition of nitrosation of the guanidine nitrate suspended in concentrated nitric acid as the verbal description below the drawn reactions describes. This is somewhat analogous to a nitrosation method which has been patented for production of DDNP. I suspect that if there is an extraordinary chemistry occuring as Williams has described it is probably occurring under the more extreme reaction conditions.

Attachment: US2835631_ELECTROLYTIC production NITROSOGUANIDINE.pdf (108kB)
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[Edited on 1-8-2011 by Rosco Bodine]

AndersHoveland - 1-8-2011 at 10:01

Quote: Originally posted by Rosco Bodine  

There is nothing I can find about the reaction of nitrous acid with triaminoguanidine


that is probably because the diazotization of aminoguanidine has loses. when three groups are to be converted on the same molecule, the yield is much lower due probability. For example, if the yields on one group are 70% conversion, then the yields converting all three groups would be only 34%, simple probability theory. This is one of the reasons that it is typically difficult to add more than one nitro group to the same molecule.

Rosco Bodine - 1-8-2011 at 10:52

What you are decribing may seem right, but I think you are only guessing and guessing wrong. Your guess does not square with the 77% yield of tetrazolyl azide gotten from diazotization of diaminoguanidine, which is comparable with yields of the modified compound gotten from nitrosation of the analogue monoaminoguanidine. This is totally unrelated so far as I understand to the introduction of nitro groups.

What I was suspecting or by intuition thinking may happen with a nitrosation of triaminoguanidine is that a pentazole or pentazole variant may result as the product, but that may be an unstable intermediate product which could soon lose nitrogen and partially decompose to a more stable tetrazole, possibly giving the same tetrazolyl azide as is gotten from diaminoguanidine.

[Edited on 1-8-2011 by Rosco Bodine]

The_Davster - 1-8-2011 at 12:18

Rosco: http://onlinelibrary.wiley.com/doi/10.1002/anie.201100300/ab...

Rosco Bodine - 1-8-2011 at 12:24

Ha ! :D It's cutting edge current technology stuff we are working on and contemplating ......
soooo...great minds think alike .....what else can be said.

You got that article on you? (sharing is caring)

I just put a request in references and will attach that article here when I get it.

Thanks for that citation

[Edited on 1-8-2011 by Rosco Bodine]

AndersHoveland - 1-8-2011 at 15:36

Since we already know the result of diazotization of diaminoguanidine, perhaps we should look into what happens when hydrazones are diazotized.

Hydrazone is R2C=NNH2

https://kb.osu.edu/dspace/bitstream/handle/1811/5721/V72N05_...

The diazotization of triaminoguanidine might result in:
(N3)2C=N-NH-N=C(N3)2


"Diazotization and subsequent dimerization of the triaminoguanidinium cation yielded 1-diazidocarbamoyl-5-azido​tetrazole" the picture shows
(N3)2C=N-N=(N4C)N3
there must be a hydrogen atom on this molecule, but the picture does not show where it is.

tag2.GIF - 17kB

[Edited on 2-8-2011 by AndersHoveland]

Rosco Bodine - 1-8-2011 at 18:12

Here attached is the article for the nitrosation product of triaminoguanidine. Additionally are a couple of other articles of related interest concerning Dinitromethyltetrazole and an article describing a nitroguanidine guanidine nitrate double salt. Thanks to solo.

At first glance it would seem that the most interesting possibilities operative for the C2N14 are related to the predimerization intermediate which would be interesting to see how it may react with cyanoguanidine particularly, or
some other materials. The C2N14 is itself too sensitive to be
of any practical use, so I would think its predimerization intermediate or C2N14 itself as a higher intermediate would still be interesting.

The C2N14 is isomeric with isocyanogen tetraazide described by US2990412 attached. The stability of the isocyanogen tetraazide is much better than the C2N14 gotten from nitrosation of triaminoguanidine.

Dinitromethyltetrazole is described also in US3173921 attached.

Attachment: C2N14 An Energetic and Highly Sensitive Binary Azidotetrazole.pdf (403kB)
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Attachment: Dinitromethyltetrazole and its Salts A Comprehensive Study.pdf (744kB)
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Attachment: dinitromethyltetrazole.pdf (136kB)
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Attachment: The energetic double salt nitroguanidinium nitrate guanidinium nitrate.pdf (976kB)
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Attachment: US2990412 Isocyanogen TetraAzide.pdf (60kB)
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Attachment: US3173921_DINITROMETHYLTETRAZOLE_AND_SALTS.pdf (140kB)
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Attachment: C2N14_supporting_information.pdf (994kB)
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[Edited on 2-8-2011 by Rosco Bodine]

1,5-Diamino-1H-tetrazole from diaminoguanidine via Nitrite and HCl

Rosco Bodine - 4-8-2011 at 09:56

@Engager With regards to your work with DAT which has discussion beginning on page 5 of this thread, later on page 8 was posted a link by AH-Poster to a page which contained a synthesis which was a "copy and paste" edit and summary having no attribution as to source. Attached is the source reference which would correspond with that linked page of "excerpted" information which provided no references.

Plainly the reaction of nitrous acid with diaminoguanidine can either lead to DAT as the product in 58% yield by a 1:1 molar ratio in a mineral acid (HCl) as reported by the attached article.

Alternately when the reaction uses a molar ratio of 2:1 and a buffered pH as described in the Lieber and Levering article attached previously, a 77% yield of Tetrazolyl Azide is reported.

Attachment: Diaminotetrazole from Nitrosation of Diaminoguanidine in HCl.pdf (492kB)
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In spite of the observation by Klapotke about various reaction conditions only producing differing yields of one product from the reaction of nitrous acid and triaminoguanidine, the different products gotten by different conditions for the mono and diaminoguanidines, and similar precursors strongly suggests that varied conditions of pH and molar ratios would be expected to produce different products from triaminoguanidine as is the pattern for similar reactions. It causes me to wonder if Klapotke is correct or incorrect, and if Klapotke is correct, then why is triaminoguanidine the exception to the usual pattern?

[Edited on 4-8-2011 by Rosco Bodine]

possible alternate route to guanyl azide or analogue

Rosco Bodine - 7-8-2011 at 10:47

There seems to be a possible nexus which I have recognized about the reaction conditions involving the reaction of guanidine with nitrous acid to form cyanamide or its dimer,
and the parallel reaction where nitrous acid is reacted with semicarbazide to produce carbamoyl azide (also called carbamyl azide or possibly? carbamazide) See the thread on Azides for additional references.
http://www.sciencemadness.org/talk/viewthread.php?tid=1987&a...



http://www.chembase.com/cbid_458420.htm

http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=4584...

It would seem possible that the carbamyl azide itself or its ammonium azide or sodium azide hydrolysis product would
react with the cyanamide or its dimer gotten from nitrous acid and guandine, eventually leading to 5-aminotetrazole.

The dynamics of the reaction are unknown but the necessary elements are there for a possible one pot reaction for example of semicarbazide salt, guanidine salt, and a nitrite salt to react and produce 5-aminotetrazole or a derivative
or analogue.

Hydrazine sulfate might react similarly as semicarbazide in such a scheme, although less likely since reportedly an elevated temperature was reportedly required for the oxidation of hydrazine to hydrazoic acid by nitrous acid, subject to losses for the elevated temperature and
the limitation of the theoretical 50% yield for a reaction which converts only half the hydrazine, the other half being byproduct ammonia.

Anyway the parallel and similar reactions point to an alternate possible route to 5-aminotetrazole or derivative or analogue.

There is some basis in the literature to support my identification of this nexus involving nitrosation of semicarbazide to carabamyl azide and nitrosation of guanidine to cyanamide in particular, or its dimer, as being a potential alternate reaction scheme for producing 5-aminotetrazole, even though it may require sequencing
or may not go well as a one pot method. See attached article page 2 second paragraph regarding hydrolysis of
dicyandiazide which results in a similar reaction system
where cyanamide and hydrazoic acid then further react to form the 5-aminotetrazole.

CARBONIC ACID AZIDES
Charles Vinton Hart
J. Am. Chem. Soc.
1928, 50 (7), pp 1922–1930
DOI: 10.1021/ja01394a017

Also attached is another article more of interest with regards to the general topic of tetrazoles.

Cyanoguanyl Azide Chemistry
William P. Norris, Ronald A. Henry
J. Org. Chem.
1964, 29 (3), pp 650–660
DOI: 10.1021/jo01026a032

Attachment: CARBONIC ACID AZIDES.pdf (600kB)
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Attachment: Cyanoguanyl Azide Chemistry.pdf (1.5MB)
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@Boffis & @Engager It appears that even if the Williams reported route to aminotetrazole turns out to be a typographical error not caught in editing, or an incorrect oversimplification, Williams still has pointed us to some interesting alternative reactions which should be able to work using hydrazine or a hydrazine derivative. This agrees with the more conventional known reaction schemes, which require use of hydrazine or a hydrazine derivative. So in summary, if the "magic" reaction of Williams doesn't work, a variation using hydrazine or a derivative of hydrazine may prove almost as convenient and more workable.

[Edited on 8-8-2011 by Rosco Bodine]

Rosco Bodine - 10-8-2011 at 17:39

Quote: Originally posted by Boffis  
Hi Guys,

I have already considered these reactions and there are numerous possibilities. I have already considered the nitrosoguanidine reaction (see the attached pdf of my "thinking document") and I believe the trace contaminant of yellow material in the first crop of crystals to be nitrosoguanidine. I also discuss the possible nitroso compound + amine compound = azo compound. This could lead to a triazene that may de-arrange to aminotetrazole; several such de-arrangements have already been published and I have quoted examples.

Take a look at the attached document and have a go at some of the reactions. And please, I found the claim in Williams book difficult to believe too at first, but as I investigate these reactions it is becoming clear that the chemsitry of urea and guanidines is very complex and very sensitive to conditions. So simply quoting an equation is meaningless without giving the conditions. I am very aware that I have not proved the identity of the product of my reactions but equally I can assure you that cyanamide and urea are not important componenets of the first crop of crystals, cyanamide is too soluble and urea too sensitive to nitrite. After boil down, the second crop of crystals could contain almost anything; cyanoguanidine, melamine etc but a yellow contaminant is still present.

When I am home next I will try preparing nitrosoguanidine by both routes and then try reacting it with guanidine to see if I can isolate the triazene and then make it de-arrange to aminotetrazole. As a say in my document I don't see these reactions as a route to cyanamide particularly but almost any N-N bearing product would be a potential precursor to the tetrazole.

Attached article link from preceding page
http://www.sciencemadness.org/talk/files.php?pid=216853&...



You know I have been looking at your document :D
Okay I'll go out on a limb here with some speculation
which may be right or wrong. There is another possibility here regarding your "hydroxyazoguanidine" ....that it may be unstable.... and lose water to form an azide, and that azide reacts with cyanamide or cyanoguanidine being produced as a parallel reaction product, leading to 5-aminotetrazole. It seems possible in such case that Williams could be in part correct by identifying an end product that does occur, but is incorrect about the reaction mechanism leading to that product. This possibility would allow for the study at Cornell
by Bancroft and Belden to also be correct, since cyanamide or cyanoguanidine would be required for reaction with the azide I speculate may form as a decomposition product of your "hydroxyazoguanidine".

There is identified in the literature a similar reaction involving the nitrosation of semicarbazide, see near the bottom of page 14 of the attached document, where the first product
for the reaction of semicarbazide with nitrous acid then loses water and decomposes to carbamoyl azide. I am speculating that an analogous reaction may occur with
your "hydroxyazoguanidine", which decomposes to NH2CN3 "deoxycarbamoyl azide" (exist?)...(possible?) and further reacts with cyanamide or cyanoguanidine ...(possible?) to form the 5-aminotetrazole

Nicodem should love this :D Alright call in the big guns

Attachment: Ueber Semicarbazid.pdf (1.6MB)
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Attached are solubilities for 5-aminotetrazole monohydrate
low solubility of 1.38% @ 20C
and worth noting the much higher solubility for the guanidinium salt of 5-aminotetrazole which is 75%

Another low solubility product which might possibly appear is cyanuric acid, from trimerization of cyanic acid

Attachment: atz.pdf (87kB)
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Attachment: ga.pdf (87kB)
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[Edited on 11-8-2011 by Rosco Bodine]

Boffis - 11-8-2011 at 22:08

There's certainly some interesting chemistry here again and it's going to take a little time to digest it.

However, one thing strikes me about your proposed mechanism is the rearranement of my hypothetical "hydroxy azoguanidine" to an azide. The problem I see is that this requires the migration of a nitrogen moiety from the central carbon atom to a nitrogen and to displace a hydrogen from the imide or amide group. I have been unable to find another such reaction and it sound rather thermodynamically unlikely. The only way I can see to do this is via a bi-molecular condensation and then de-arrangement to give an azide or hydrazoic acid, much along the lines of what I discussed before. Also I think if "deoxycarbamyl azide" (azocarbimine?) were produced it would rearranged to unsubstituted tetrazole directly.

I agree about the cyanuric acid being a possibility and I will test this when I get home.

Rosco Bodine - 11-8-2011 at 23:09

I agree such a reaction is unlikely. I was thinking cyanamide is probably formed, so it follows that a likely parallel reactant would be an azide leading to hydrazoic acid which could react with the cyanamide. The only similar reaction I could find was the carbamoyl azide formation, which reportedly does hydrolyze further to HN3 and cyanic acid, the cyanic acid then decomposing to NH3 and CO2 by further hydrolysis. The pathways these reactions may follow is uncertain and this has become a guessing game where only experiments and qualitative analysis of the products gotten from various reaction conditions will provide better understanding of the mechanisms.

I still do think using hydrazine sulfate to react with cyanamide from a first nitrosation of guanidine to form aminoguanidine and then a subsequent nitrosation to guanyl azide is probably the easiest way of salvaging the process if it turns out that the product Williams described is incorrect. However, if Williams got it right, then I think the most likely scheme is shown by your reactions #3 and #4 .

I was looking at the carbamoyl azide primarily in connection with the parallel topic thread on azides, since it suggests a possible simplified route to synthesis of azides via nitrosation of semicarbazide, hopefully leaving a solution of ammonium azide as the end product.

The reactions are very similar for carbamoyl azide and guanyl azide ....except that carabamoyl azide does not cyclize directly to a ring compound. I think carbamoyl azide probably would react with cyanamide and lead to aminotetrazole via the hydrazoic acid intermediate from hydrolysis which would add to cyanamide directly.

It is something I have been trying to find whether or not carbamoyl azide forms salts such as a nitrate, picrate, styphnate, or a perchlorate, similarly as does guanyl azide. Those contemplated salts of carbamoyl azide could have useful properties as energetic materials. I can find nothing about such seemingly possible compounds.

[Edited on 12-8-2011 by Rosco Bodine]

NH4FeNT

dangerous amateur - 1-9-2011 at 03:56

Does somebody here have some experience with some experience with the ammonium-iron NT complex?
Yes, I read trough Engagers great posts.

In the Green Primaries PDF the mention iron(II)chloride hexahydrate.
To my knowledge, this compound only forms a tetrahydrate...

Or do the mean iron(III)chloride?

Formatik - 5-9-2011 at 23:08

Some while back, I nitrated 5-ATZ monohydrate using excess fuming red acid (84 to 90.1%) similar as the method indicated on page six of this thread, but scaled it down by a factor of about four. However, the acid should at best colorless, red fuming acid might be dangerous!!! After the process, the obtained white powder was let dry under the sun. The liquid liquor of this containing some of the powder, nitric acid, and water was saved. The powder should be 5-nitrimino-1H-tetrazole (5-NAMTZ), or its hydrate. With the powder, I couldn't get a reaction using hammer blows it being flat between Al-foil on an iron plate. Reaction to flame: after it melted (maybe the H2O also to come off) it burned off vigorously with a sizzling hiss and an orange-yellow flame.

When the acidic liquor was added to Aq. AgNO3, it gave an immediate precipitate which may have looked white at first but turned light yellow, though it is not very light sensitive. Aq. Pb(NO3)2, Cu(NO3)2 made no precipitates, also not on standing. Aq. Hg(NO3)2 gave a white precipitate, which when dry decomposed and deflagrated only mildly from a flame, even when confined in Al foil. Combining the acidic liquor with vigorous reacting acidic Cu(NO3)2 and N2H5OH, caused this reaction to calm down and left a brown precipitate which after filtering later turned olive-green on drying; a few crystals held in a flame, would dance around burning with a green flame popping weakly, burning incompletley only. A small amount only popped mildly (like silver methylacetylide, but without the soot) when confined in Al foil and heated over a flame.

The silver salt should be silver nitriminotetrazolate: when dry, a big crystal of it snapped weakly from an open flame and left residue and a part of the crystal may have launched off. But when wrapped in Al-foil, a very small mg amount heated over a flame gave a strong detonation with a loud report. Actually, even unconfined heating from underneath on the foil in the open with a flame caused detonation. It has a high "temperature of explosion" because it could be heated over the flame a good few seconds before it responded. A face shield was needed to protect the face from shrapnel. A crystal put into Al-foil flattened normally and then hit with a mild hammer (0.5kg) blow did nothing, strong blows also nothing. It's not very sensitive to shock. An amount around 0.005g of the silver salt can be seen below, next to a pencil for scale and when it was confined in foil and heated, it detonated sounding like a gunshot (amounts near 2 to 5mg yield detonations that sound like gunshots).

The same acidic liquor in aq. solution when combined with N2H5OH ought to give a mixture of hydrazine nitriminotetrazole + hydrazinium nitrate. Combining the liquor and N2H5OH, then evaporating this under the sun for several hours in a dish, gave a thick syrup of faint beige yellow color, and faint hydrazine smell. This didn't react to open flame, but when heated on foil, it boiled off the water and then 'thumped out' violently burning off with a yellow-orange flame.

Hydrazinium aminotetrazolate has a very high detonation rate, even exceeding HMX. But it is very insensitive to initiation and Klapoetke could not initiate it using PETN booster. He speculates wether an RDX booster could work (link here). Perhaps one might be also able sensitize it and improve its energy content, heighten density, by combination with tetranitromethane, hydrazinium nitrate, etc.

I've evaporated a small amount of aq. N2H5OH in excess, which was mixed with 5-ATZ and after a few days left a colorless syrup, which only very slowly crystallized on its own. A drop of this heated over a flame on Al foil caused the H2O to evaporate, then after melting sometime it flashed out vigorously burning off quickly with a noisy orange-yellow flame.

AgNAMTZ.png - 301kB

[Edited on 6-9-2011 by Formatik]

Rosco Bodine - 6-9-2011 at 09:54

Quote: Originally posted by Formatik  
An amount around 0.005g of the silver salt can be seen below, next to a pencil for scale and when it was confined in foil and heated, it detonated sounding like a gunshot (amounts near 2 to 5mg yield detonations that sound like gunshots).


2-5mg sounds like a gunshot huh.......
that's a lot of sass from such a tiny mass :D

Maybe about 50mg made into a paste with dextrin and dried into a pellet around a bridgewire in a squib cavity could be good for something or another. Pushed firmly against a column of compressed PETN the two could probably really communicate.

Formatik - 6-9-2011 at 12:34

Yes, it gave me quite an unexpected shock because of its flimsy reaction to open flame. It could make for a great party gag.

Silver nitriminotetrazolate and disilver(aminotetrazol) perchlorate have been said to be the two most promising compounds for replacing the most useful initiator for insensitive HNS, which is currently Cd(N3)2.

I've thought about another oxidant that will work for forming azotetrazolates: calcium hypochlorite.

Comprehensive Heterocyclic Chemistry by Katritzky (below) states Ca(OCl)2 can be used also, referencing the 8th volume of F.R. Benson's Heterocyclic Compounds. There was also another azotetrazole compound formed using Ca(OCl)2 I was reading about in Beilstein somewhere, but I can't find the details right now.

azotetrazolateoxidant.png - 195kB

Edit: found it. The compound being oxidatively dimerized was 2-phenyl-5-aminotetrazole.


azotetrazoleoxidation2.png - 232kB

[Edited on 7-9-2011 by Formatik]

Formatik - 13-10-2011 at 12:19

I've attempted to use aq. NaClO and conc. H2O2, instead of KMnO4 to oxidize the sodium aminotetrazolate. H2O2 did not work. NaClO seemed to work, giving deep-yellow solutions. But the apparent azotetrazolate could not be obtained because it is in a mixture with other sodium salts, likely NaCl, NaClO3 and NaOH, the latter which increases its solubility also. Crystallization gave this contaminated solid mixture. Acidification with an acid that doesn't react with the azotetrazole (hydrochloric and sulfuric acid are reported to give hydrazinotetrazole and nitric acid azidotetrazole), namely acetic acid didn't seem to give a satisfactory result either.

Thiele's method worked great, even when microscaled. The foaming from KMnO4 additions can get out of hand very fast and needs to be well controlled. The preparation of sodium azotetrazolate is very dangerous if the container being heated breaks (this nearly happened to me during heating, it cracked!), the entire contents will spill out and can explode. For preparatory purposes best would be to use a big round bottom flask and heating mantle. The flask would reduce likely hood of spilling, but foaming would need extra care because it would be able to funnel out easily. It looks like Engager used a RB flask in his preparation.

Formatik - 16-10-2011 at 12:04

Quote: Originally posted by Engager  
Stickers on boxes may not be correct subtance with sticker Cu(DATZ)2 on box is copper diazoaminotetrazole, that's why i listed correct names above picture. Actualy Cu diazoaminotetrazole is amorphous, but when it dried it stucked to paper in some kind of lumps, in wet state it's olive green, but dry it is almost black. It's quite sensitive to friction, it exploded then i tried to grind it in mortar. Explosion was quite loud, but i don't find any usefull applications for it in literature, only mentions about it's existance. Surely it is highly sensitive and powerfull explosive, but i'm not sure about it's initiative power. I have not tried ammonium complex, because i think it's too sensitive.


I'm certain copper diazoaminotetrazole has detonator properties. It undergoes DDT readily from thermal shock of e.g. burning powders, under light confinement. Copper nitrotetrazole also will DDT in the same instance, but is of course the stronger detonator. There are now copper salt detonators. That field used to belong to Pb, Ag, and Hg salts, but no longer. Another compound, cuprous nitrotetrazole, is touted already as a replacement for lead azide.

Formatik - 21-10-2011 at 11:24

Quote: Originally posted by Formatik  
After the process, the obtained white powder was let dry under the sun. The liquid liquor of this containing some of the powder, nitric acid, and water was saved. The powder should be 5-nitrimino-1H-tetrazole (5-NAMTZ), or its hydrate.


I've attempted to characterize this white powder, but I now think that it is in fact aminotetrazole nitrate. Using non-anhydrous ATZ and nitric acid, likely caused only a partial nitration and so then nitriminotetrazole likely passed into the liquor solution. Forming the pale-yellow silver salt could also be done this way (it's best not scaled up because of diazotetrazole risk): a few mg ATZ.H2O added to several drops red fuming nitric acid, this then mixed and let stand a few moments and then taking only the liquid portion of this and adding it to aq. AgNO3 under mixing, then filtering and washing.

The pale-yellow salt's reaction to open flame sounds very similar to Axt's description of the salt he made from the acid. I've attempted Ag determination but much of the fine Ag2O precipitate passed right through the filter paper, and so its silver content could not be determined. It's much less flame and impact sensitive than silver nitrotetrazolate (AgNTZ). It gave no reaction to various hammer blows directly on an iron plate (meaning it's not entierly insensitive, but its sensitivity is low). It is a highly powerful material and so should not be underestimated. It doesn't have texture issues like silver or especially copper nitrotetrazolate, it flows very good. It does not darken on standing like AgNTZ does. The high amount of thermal energy needed to explode it, is indeed in the same area as silver azide.

Concerning impact sensitivity, the sensitivity between aluminium foil does not work well even as a crude impact test. The thought was it would help powder keep from spreading during impact. But hitting several crystals of copper nitrotetrazolate in between the foil on an iron plate even with the hardest hammer blows gave no reaction, though the crystals were crushed. The aluminium foil caused forces to dissipate. A symmetrical pestle mass falling only a few centimeters directly onto the crystal detonated the copper salt (other primaries like silver acetylide complex do this also). Also mechanically speaking, indirect forces are safest there.

Formatik - 21-10-2011 at 20:07

Here is my characterization of some tetrazole compounds, of which I think complements some information in this thread. Diazoaminotetrazolates and nitrotetrazolates in particular. I've included a few references, but all of the color descriptions and other reactions were tests I've conducted. Mercury diazoaminotetrazole could be greater than or equal to in strength to other heavy metal diazoaminotetrazolates.

EDIT: Removed possibly inaccurate test information at Formatik's request.

Attachment: characterizations.pdf (63kB)
This file has been downloaded 1677 times


[Edited on 10-30-2011 by Polverone]

Guanidine-nitrous acid reaction; further experiments

Boffis - 25-10-2011 at 08:57

Returning to the subject of my earlier posts namely the reaction between guanidine hydrochloride and nitrous acid, I have now conducted some further experiments to investigate the effects of using different ratios of reactant and different levels of acidity on the outcome of this reaction.

5 experiments were conducted much as before but instead of using a 1:2 ratio of guanidine hydrochloride to sodium nitrite the new experiments used a ratio of 1:1 or 2:1 since I felt that the original experiments utilized a considerable excess of sodium nitrite.

Experiments 1, 2 and 5 used a 1:1 ratio of guanidine hydrochloride to sodium nitrite while 3 and 4 used an initial ration of 2:1. However, after a couple of days it became apparent that there was much unreacted guanidine present in the reaction solution so further sodium nitrite was added and more product recovered. In all cases less hydrochloric acid was added than initial intended because it was found that even in the cold the acid cause rapid loss of brown nitrogen oxide. In experiments 1 and 3 only a third and half of the theoretical amount on acid required to liberate all of the nitrous acid could be added even at <5°C before excessive brown fumes appeared.

No acid was added to experiment 2 initially to investigate the reaction in neutral conditions when no reaction occur after nearly a week acetic acid was used to acidify the mixture. For those interested in the details of both the reaction and the testing of the resulting product I have attached a detailed account at the end.

The conclusions are as follow:
1- Guanidine hydrochloride and sodium nitrite do not react under neutral or alkaline conditions.

2- Under weakly to moderately acid condition they react in an equimolecular ratio, the outcome of the reaction being dependant on acidity and temperature;
Under weakly acid condition such as in the presence of acetic acid nitrosoguanidine is an important or main product but the yield is less than 15% and contaminated with the white product.
Under more acid condition in the presence of hydrochloric acid and at low temperature <5°C the white crystalline substance is the major product.

3- Under highly acid condition and at room temperature there is a copious evolution of nitrogen with the production of cyanamide or urea (Bancroft and Beldon).

4- The creamy white material remains unidentified but it is not explosive nor does it deflagrate but when heated it decomposes and leaves only a trace of white residue. It is, however, not aminotetrazole.

Work will continue into identifying the white product.

I tried to insert some photos but an error message appears saying that they are too large even though they are clearly not at 500h x 900w pixels. Does anyone know what the problem is?

Attachment: Further Experiments on guanidine-nitrous reaction.pdf (507kB)
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quicksilver - 25-10-2011 at 09:11

Interesting experiment and nicely documented.

In your notation (2) what was the weight of product yield? If unknown do you have an estimate?

As white material is isolated (4) what tests will you preform on the "white creamy" yield? as you have already tested heat exposure, have you tested impact?

__________
Problems inserting photos:
Photos and all insertions are limited to 2Mb - is it over that limit?



EDIT: digital pH meter is useful tool to find at what point you get your reaction (not expensive either).



[Edited on 25-10-2011 by quicksilver]

Rosco Bodine - 25-10-2011 at 10:28

That file attachment is password protected and won't open.

Try a 600 pixel width on the photos

Boffis - 25-10-2011 at 11:32

@Rosco, sorry about that try this version.

Attachment: Further Experiments on guanidine-nitrous reaction.pdf (506kB)
This file has been downloaded 1707 times


Boffis - 25-10-2011 at 14:48

@Quicksilver When I get time I intend to do a mp determination on the recrystallised creamy white material. I dont have an accurate thermometer at present that operates at over 110 C which is why I haven't do mp before. I also need to find a better solvent because the yellow material is a persistent contaminant when recrystallized from water. I an almost keen to determine if the compound contain a C-N-N-C linkage or even C-N=N-N-C. or whether is is only a C1 compound but I am not sure about how to do this other than a molecular weight determination (which I am currently reading up on)

I am also looking into other tests, I may have sourced some Xanthohydrol and I haven't tried the ammonical silver nitrate test on this product yet.

I put all of the important picture in the attached pdf.

Rosco Bodine - 27-10-2011 at 09:31

@Boffis Your experimental results are conflicting with and possibly debunking the published literature or what would be expected and predicted from a reading of the published literature. Were you able to determine if cyanuric acid is present in the product? I am still thinking that some sequencing of reactions but involving hydrazine as an additional reactant may be required. From the time I first was looking at these reactions it seemed to make more sense to me having hydrazine as a component in the reaction sequence. I haven't gotten back into trying to visualize the reactions again for being otherwise occupied.

Boffis - 27-10-2011 at 10:58

My results certainly conflict with the claim of Williams but not necessarily with those of Beldon et al since they used more acid conditions. There is still a fair bit of work to do to identify the creamy white material. First I need to find a solvent to remove the the nitrosoguanidine and then determine the melting point.

Boffis - 27-10-2011 at 14:16

On the point of cyanuric acid; no but I can't think of a method of testing for it apart, perhaps, from its ability to form insoluble salts with Ag or Pb but in the presence of so much chloride from the initial reactant Pb could not be used and cyanamide reacts with ammonical Ag nitrate so a ppt would probably be inconclusive.

Does anybody know of a test for cyanuric acid? There is a book dating from about 1930 by a German chemist called either Feigl or Angers that is full of useful spot test for organic chemicals if anyone has a copy or know the title. These two chemist later collaberated on a classic text book on inorganic spot test a little later.

Rosco Bodine - 27-10-2011 at 15:00

Quote: Originally posted by Boffis  
On the point of cyanuric acid; no but I can't think of a method of testing for it apart, perhaps, from its ability to form insoluble salts with Ag or Pb but in the presence of so much chloride from the initial reactant Pb could not be used and cyanamide reacts with ammonical Ag nitrate so a ppt would probably be inconclusive.

Does anybody know of a test for cyanuric acid? There is a book dating from about 1930 by a German chemist called either Feigl or Angers that is full of useful spot test for organic chemicals if anyone has a copy or know the title. These two chemist later collaberated on a classic text book on inorganic spot test a little later.


Calcium cyanurate is virtually insoluble so adding calcium chloride would be a good spot test there. Also the sodium cyanurate should have increased solubility over the free cyanuric acid, although the solubility of either one is not great, and a hot water titration might identify cyanuric acid by neutralization equivalent revealing the tri-acid character of the cyanuric acid for an aliquot as related to its mole weight. Hydrates exist for cyanuric acid and its salts which will have bearing on quantitative weight calculations for the solid samples. You could also see what is the heat response for the cyanuric acid as heat should depolymerize and volatilize cyanuric acid as cyanic acid which may sublime and repolymerize again as a condensate on the cooler part of test tube. Heating the sodium salt should result in a thermal decomposition product testing postive for sodium cyanate.

[Edited on 27-10-2011 by Rosco Bodine]

Boffis - 27-10-2011 at 17:58

@ Rosco

Thanks for this information I will try it out. I have a little cyanuric acid byproduct of some work I did a while back, enough to try this out I thing.

By the way I have just looked on Amazon and the book I was thinking of is: Spot tests in organic analysis by Fritz Feigl (Hardcover - 1960)
5 used from £9.91

I've just bought one for GB pounds 13; If anyone is interested Ièll let you know how good it is!

almaz - 17-11-2011 at 09:31

I prepared mercury nitrotetrazolates in it method:
1 solution. Sodium nitrite 3g and 1,6g copper sulphate nave in 10ml the waters.
2 solution. 1,5g ATZ, 0,06g copper sulphate in 15,45ml 58% nitric acid + 7ml water. The solution 2 I dripped to solution 2 and cooling at current 1,5 hours. The spume, oxides of the nitrogen and microdetonates did not observe. After 40 minutes the mixture became thicken. On completion of the else 15 minutes and dripping 17ml 58% nitric acid + 7ml waters, via one hour the copper salt sediment has washed at 7ml 58% nitric acid + 35ml waters. The sediment neutralized sodium hydroxides and boiled it 30 minutes. At not it filtrated, copper oxides washed at 15ml of boiling waters. In solution the, I dripped acid up to PH=4, evaporation of water and cooling give crystals. For clear has dissolved the crystals in 50ml boiling acetone. It filtered and vaporized the solvent. This give the painted crystals.
The receprion to mercury salt:
0,1g sodium nitrotetrazolates dissolved in 0,7ml waters + 0,1ml nitric acid. And when heating in not water flowed the solution, contacting 0,15g nitrate mercury dissolved in 0,5ml waters + 0,01ml acid. After slow cooling fall out the heavy crystals of beige colour, reminding croups.
Has Elsa got silver salt - they the most small white needles.
The Minute quantity mercury salt - has overpunched in 3mm glass hole. From action of the blaze immediately detonates.
Photo:
0,051-5-aminotetrazol
0,053-mixture before filrering
0,058-copper nitroterazolates
0,059-mixture on water bath
0,056-sodium salt.

[Edited on 17-11-2011 by almaz]

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almaz - 24-11-2011 at 08:42

Quote: Originally posted by almaz  
2g aminotetrazole has
dissolved in
19,6ml 15 % of a solution
NaOH. Heated up to
100с also poured the small.
In the portions 2,7g KMnO4 to
Dark coloring
Liquids (dark green).
Observed strong boiling up
liquids. Upon termination of
Additions has flowed for
Surplus removals
Permanganate 0.5ml C2H5OH.
After hour heating
At 100c, hot quickly
Filtered from big a stake -
ва MnO2, the deposit has
washed out on
The filter 2х25ml
distilled boiled water and all
The filtrate evaporated to 1/3
Initial volume. After
Coolings drop out the yellow
crystals 2,9g (~70% ) sodium azotetrazolate


Sodium azotetrazolate.jpg - 56kB

almaz - 25-11-2011 at 03:29

dry weigh -2,1g (88% theory)

Formatik - 27-12-2011 at 21:14

Well, another oxidant that works great for oxidizing sodium aminotetrazolate to sodium azotetrazolate is potassium persulfate (K2S2O8). I would prefer this over the messy KMnO4, and alcohol is not needed to destroy any excess either. No filtering of the MnO2 is required either. I've tried it with this persulfate and it worked, but I didn't characterize the yield so good because it was in the microscale, the yield is probably around the same like by permanganate. The sodium azotetrazolate made from K2S2O8 reacted to open flame the same way as the one made from KMnO4, there was also no reaction from hammer slamming on an iron plate. The appearance was the same also.

I also stated in the previous document ethanol can be used to wash sodium azotetrazolate, this is true as long as no preparation liquid liquor is present, otherwise a white compound (no apparent energetic properties after isolation) begins to precipitate.

To any who might have wondered, there was some inaccuracies of weighing and amounts in the previous document, which is why I requested it be deleted. Mercury diazoaminotetrazolate is actually similar in brisance as the silver and copper salt, which are similar to silver fulminate and lead azide. The mercury diazoaminotetrazolate is especially very friction sensitive, but shock sensitivity was not easy to determine.

Silver azotetrazolate has been known for over 100 years, but there is not much information on it in the literature. I've made it and found it is not as sensitive as Thiele had originally claimed, neither is the mercury salt. They don't explode by simply being contacted. The silver salt is extremely shock sensitive, sensitivity is similar to acetone superoxide and silver fulminate. It is less sensitive to friction than the latter compound. It is a black-orange solid when dry and it dries out in very hard clumps. Small amounts (like 5mg) could be broken up with a wooden match on tissue paper on a hard surface (a mortar and pestle or rod are much more likely to end in explosion). It is a dangerous novelty energetic like silver fulminate. There is a picture of it drying on a filter paper below.

agazotet.png - 569kB

I found silver azotetrazolate (AgAZT) is extremely sensitive to static shock and it detonated readily, compared to e.g. lead azide or silver diazoaminotetrazole which didn't fire from piezoelectric sparks, even though I zapped the hell out of these two. In one of the detonations, the voltmeter reading was about 9.2mV. Weaker discharges like 0.4mV gave no reaction. The compounds were on the edge of an aluminium strip in very small piles or pieces then discharged. The piezoelectric sparks are strong enough to feel on the human skin, but they are not as strong as some of the static discharges humans can generate.

When the silver azotetrazolate was put on a pretty non-conductive strip (paper) and exposed to piezoelectric jolts, the jolts despite being done numerous times would not "seek out" the silver azotetrazolate. Even when the silver azotetrazolate was between the piezoelectric spark source and the metal contact of the lighter (this easily causes detonation when an aluminium strip is used). The material was not conductive enough on its own to attract the spark. The light sensitivity of silver salts which froms silver, and increases static discharge hazard.

Mechanical sparks from a lighter readily detonated silver azotetrazolate (lead azide and copper diazoaminotetrazolate did not react). AgAZT also detonates on flame contact but reacts slower than lead azide, which was slower than silver fulminate. The loud report is significantly louder than either of the two latter compounds. The brisance is similar to or possibly even surpasses silver azide, and so must be treated with utmost care.

Mercury azotetrazolate was a yellow gelatinous volumous precipitate which turns orange when dry. It was very friction sensitive (shock sensitivity ought to be extreme though it wasn't tested), but a few small crystals could be gently scraped without reaction. The brisance seems similar to the silver salt. The copper azotetrazole salt was a black-green solid when dry extremely shock and friction sensitive, significantly less brisant than the silver salt.

Concerning Thiele's sensitivity claim of heavy metal azotetrazolates, it was quite a vague characterization and he lumped the Pb, Ag, Hg salts together claiming they explode from slightest action. I don't know what he did but it is known shock sensitivity increases with larger amounts so perhaps he made gram amounts and then bumped at them with a long stick when they were dry.

AndersHoveland - 27-12-2011 at 23:06

Quote: Originally posted by Formatik  
Well, another oxidant that works great for oxidizing sodium aminotetrazolate to sodium azotetrazolate is potassium persulfate (K2S2O8). I would prefer this over the messy KMnO4, and alcohol is not needed to destroy any excess either. No filtering of the MnO2 is required either. I've tried it with this persulfate and it worked, but I didn't characterize the yield so good because it was in the microscale, the yield is probably around the same like by permanganate. The sodium azotetrazolate made from K2S2O8 reacted to open flame the same way as the one made from KMnO4, there was also no reaction from hammer slamming on an iron plate. The appearance was the same also.

I also stated in the previous document ethanol can be used to wash sodium azotetrazolate, this is true as long as no preparation liquid liquor is present, otherwise a white compound (no apparent energetic properties after isolation) begins to precipitate.


I am so happy someone finally reacted aminotetrazole (or at least its salt) with persulfate. Formatik, it is quite possible that you actually oxidized it further, beyond just azotetrazole. Persulfate can oxidize nitrotetrazole to nitrotetrazole oxide. Furthermore, the azo linking group may likely have been oxidized to an azoxy group. In other words, you may have obtained N,N’-azoxy-5,5’-bis[tetrazole-2-oxide], formula C2N10H2O3.

Formatik - 27-12-2011 at 23:14

The thought of the persulfate potentially changing the product was a possibility I considered, but I have strong doubts about it oxidizing any further because the sodium azotetrazolate made was very similar to the one made by permanganate, as shown by some of the mentioned basic tests (identical appearance also).

AndersHoveland - 27-12-2011 at 23:51

But peroxysulfate can oxidize nitrotetrazole further. I see no reason why it could not similarly oxidize azotetrazole. Indeed, oxidation of the latter should be easier.

Here is the procedure for the oxidation of nitrotetrazolate to the salt of nitrotetrazole-2-oxide,
Quote:

12.5g of the sodium salt of 5-nitrotetrazole is dissolved in 50mL water, then reacted with 45g of potassium peroxy-monosulfate ("Oxone") and 20g of potassium acetate, which acts as a buffer. The solution is stirred for 24 hours at 50 degC. A solution containing 0.09 moles of tertiary amine sulfate, such as Et3NH(+), Na(+), SO4(-2), dissolved in 200mL of water, is added. Then the 5-nitro tetrazole-2N-oxide is extracted using 300mL of ethyl acetate. The yellow product moves into the ethyl acetate layer. The 5-nitro tetrazole-2N-oxide product may be purified by crystallization from EtOAc or toluene, resulting in thin yellow crystals. The yield is 70%.


Nitrotetrazole can also be oxidized by HOF, transiently formed in solution by passing elemental fluorine into a cold liquid acrylonitrile solvent in the presence of a lesser quantity of water.
"The Tetrazole 3-N-Oxide Synthesis" Tal Harel, Shlomo Rozen, School of Chemistry, Tel-Aviv University, Tel-Aviv, Israel. J. Org. Chem., 2010, 75 (9), pp 3141–3143

Now I am not sure if the extra oxygen is really in the "2-" or "3-" position. The inconsistency could possibly be due to the ambiguity between naming those two positions on the tetrazole ring, because the NH group could either be in the 1- or 4- positions. But I would think that the extra oxygen would be in the 3- position, assuming the hydrogen atom was in the 1- position (wikipedia shows this), such that the NH group could be electron donating to the oxygen atom. Hopefully you understand what I am saying.

[Edited on 28-12-2011 by AndersHoveland]

Formatik - 28-12-2011 at 00:17

I have made sodium azoxyazotetrazolate and this material is lighter in color than azotetrazolate, and it also reacts significantly more violently towards flame. So I'm still in doubt a further oxidation occurred.

Formatik - 29-12-2011 at 09:26

I was tierd when I wrote above, I meant sodium azoxytetrazolate. My descriptions on it are given in the previous pdf file on the other page of this thread.

Anyways, Anders the reference you cited used peroxymonosulfate, whereas I used peroxydisulfate. I also may have had a reference somewhere which stated potassium peroxydisulfate can be used in azotetrazole oxidation, but I can not find it right now. Maybe monopersulfate does from something different.

AndersHoveland - 29-12-2011 at 15:14

I think that the reactivity of peroxydisulfate and peroxymonosulfate are essentially the same, if not, peroxydisulfate would probably the more powerful oxidizer. From a quick internet search, the reduction potentials apparently are,
peroxymonosulfate 1.44 V
peroxydisulfate 2.1 V
(note that these values are not for boiling solutions, and are in the absence of transition metal ions, either of which increase the oxidation strength)

But the subject of possible differences in oxidizing strength or reactivity between the two regents are complicated, and probably deserving of a separate discussion (a new thread).

[Edited on 29-12-2011 by AndersHoveland]

5-Dinitromethyltetrazole

AndersHoveland - 19-1-2012 at 16:52

I think the most promisting energetic compound may be dinitromethyl tetrazole.
“Syntheis of 5-Dinitromethyltetrazole”, A. V. Shastin, B. L. Korsunskii, T. I. Godovikova, V. P. Lodygina. (2009) Russia

The structure of this compound has resemblance to another well-described insensitive energetic compound, diaminodinitroethylene (Fox-7).

Dinitromethyl tetrazole is somewhat acidic and can form salts.

Measurements of the explosive properties of dinitromethyl tetrazole have not been reported, but I think it would have an excellent combination of explosive performance and stability.

The aromatic nature of the ring would stabilize the nitrogen atoms, while the two NH groups be electron-donating toward the geminal nitro groups, stabilizing them. Many energetic tetrazole compounds have lower sensitivities than RDX, and Fox-7, which also contains the gem-dinitro functional group, is roughly twice as resistant to impact as HMX.

dinitromethyltetrazole02.png - 2kB

To make dinitromethyl tetrazole, one possible route might be:
React hydrazine hydrate with acetamidine to form aminoacetamidine, NH2-NH-C(=NH)-CH3, then react with acidified NaNO2 to form 5-methyl-tetrazole. Then simply perform a mixed acid nitration. For example, one of the preparation routes of Fox-7 involves the nitration of 2-methyl imidazole.

EDIT to the above: there is a Korean paper in which it is stated that this route was attempted but failed to give the desired product,
Quote:

Nitration of 5-methyltetrazole
Among the tactics for synthesizing target molecule, initial attention focused upon the nitration of 5-methyltetrazole. Previously, various starting materials such as 2-methylimidazole, 2-methoxy-2-methyl-imidazolidine-4,5-dione,and2-methylpyrimidine-4,6-dione(4,5-dihydroxy-2-methylpyrimidine) were nitrated and then hydrolyzed togive FOX-7 by somewhat different process. Since the methyl group was converted to dinitromethylidene moiety in all methods, nitration of 5-methyltetrazole was attempted to afford 5-dinitromethylidene-1,4-dihydrotetrazole. But this reaction failed to proceed, and most of the starting material was recovered.



Because of the aromaticity, 5-Dinitromethyltetrazole probably forms brightly colored crystals. Fox-7, for example, forms transparent yellow bipyramidal rhomboid-shaped crystal plates.

One of the energetic salts of nitromethyltetrazole has a (calculated?) detonation velocity of 9188 m/sec @ 1.87g/cm3.
[salt 4] "Energetic mono and dibasic 5-dinitromethyltetrazolates: synthesis, properties, and particle processing", Zhuo Zeng, Haixiang Gao, Brendan Twamley and Jean'ne M. Shreeve, J. Mater. Chem., 2007, 17, 3819-3826

[Edited on 20-1-2012 by AndersHoveland]

The_Davster - 19-1-2012 at 22:07

http://onlinelibrary.wiley.com/doi/10.1002/prep.200900049/ab...

"Dinitromethyltetrazole and its salts: A comprehensive study"

AndersHoveland - 20-1-2012 at 14:20

One of the other, less practical, synthesis routes to dinitromethyltetrazole involved reacting trinitroacetonitrile with sodium azide and acetic acid at (minus) -35 °C.
A. V. Shastin, T. I. Godovikova, B. L. Korsunshii, Journal of Heterocyclic Chemistry, 1998, 34, 383
(the reason for the cold temperature was because excess acetonitrile acted as the liquid solvent)

Alternatively, the sodium salt of dinitroacetonitrile can be reacted with aqueous sodium azide, but the yields from this variation are only about 10%.

For preparing the trinitroacetonitrile,
Quote:

Trinitroacetonitrile can be synthesized by the nitration of cyanoacetic acid with a solution of sulfur dioxide and 98+% concentrated nitric acid in carbon tetrachloride, with 73-77% yields. The trinitroacetonitrile can be stored as a solution in the carbon tetrachloride, and need not be isolated for further use on other reactions.
NCCH2C(=O)OH + (3) HNO3 + (3)SO2 -- > NCC(NO2)3 + CO2 + (3) H2SO4

Trinitroacetonitrile is a colorless, camphor-like, crystalline compound melting at 41.5 °, and detonating violently at 220°. It hydrolyzes to carbon dioxide and the ammonium salt of nitroform by water or alcohol at ordinary temperatures.



There is another synthesis route that uses Fox-7 as the precursor to make dinitromethyltetrazole, which has already been discussed on this forum.

Here is a description of the first published synthesis of the compound, where the researchers referred to 5-dinitromethyltetrazole as "N2FOX-7":

Quote:

...we found a more convenient method to get [ethyl 5-tetrazolyldinitro-acetate] ETDNA. Because of acidity on the methylene position of [ethyltetrazolylacetate] ETA, which possesses both carbonyl group and tetrazole moiety, we considered it's possible to introduce nitro group directly. Thus we carried out the reaction of ethyl 5-tetrazolylacetate with mixed acids and obtained ETDNA in high yield, resulting that two nitro groups were successfully introduced in one pot reaction.

Synthesis of TDNM and it’s salts
With the necessary intermediates in hand, we sought to construct the N2FOX-7 using decarboxylation and elimination. Thus, various conditions were tried. When ethyl 5-tetrazolyldinitro-acetate was treated with water, 5-dinitromethyltetrazole was readily given. Hydrolysis followed by decarboxylation took place completely within 2 h at 50 °C. In the treatment of 5-dinitromethyltetrazole with KOH, dipotassium salt and monopotassium were obtained even in lower temperature, depending upon the equivalent of KOH. Mono- and di-potassium salt were confirmed by Inductively coupled plasma (ICP) mass analysis. Meanwhile, only mono ammonium salt was given in the reaction with ammonia regardless of equivalents. 5-Dinitromethyltetrazole was also afforded by an acid treatment of the salts. As a result, hydrolysis and decarboxylation of ETDNA was achieved not only underacidic or basic condition but under aqueous one at room temperature.This process would be much more efficient and safer to obtain TDMN and its salts than the previous methods. Preliminary experiments showed that these compounds have some explosive properties.


ethyltetrazolylacetate (ETA)
N4HC-CH2-C(=O)-O-CH2CH3

ethyl 5-tetrazolyldinitro-acetate (ETDNA)
N4HC-C(NO2)2-C(=O)-O-CH2CH3


Synthesis and Characterization of High EnergeticTetrazole and Furoxan Derivatives, (Korea)

[Edited on 21-1-2012 by AndersHoveland]

AndersHoveland - 20-1-2012 at 19:26

To make an additional comment,

Quote: Originally posted by AndersHoveland  

Nitration of 5-methyltetrazole
various starting materials such as 2-methylimidazole, 2-methoxy-2-methyl-imidazolidine-4,5-dione,and2-methylpyrimidine-4,6-dione(4,5-dihydroxy-2-methylpyrimidine) were nitrated and then hydrolyzed to give FOX-7 by somewhat different process. Since the methyl group was converted to dinitromethylidene moiety in all methods, nitration of 5-methyltetrazole was attempted to afford 5-dinitromethylidene-1,4-dihydrotetrazole. But this reaction failed to proceed, and most of the starting material was recovered.


The reason that the nitration of 5-methyltetrazole failed to proceed is probably the same reason that nitration of plain 1,2,3-triazole is essentially impossible. I suspect that the electron-withdrawing tetrazole ring pulls away electric charge from the methyl group, giving it a partial positive charge and effectively shielding it from interaction with nitronium ions, which is the mechanism of reaction in most nitrations.

To bypass this difficulty, one idea would be to brominate the methyl group with bromine in the presence of uv light. Carbon tetrachloride would be a good choice of solvent for this radical-intitiated reaction. The bromomethyltetrazole could then be reacted with sodium nitrite in DMSO to substitute the bromine atom for a nitro group, to obtain nitromethyltetrazole. This could then be nitrated to give the final dinitromethyltetrazole product. 4-nitro-1,2,3-triazole, for example, can be readily nitrated to 4,5-dinitro-1,2,3-triazole.

For more details these types of substitution reactions, included is the procedure for nitroethane from ethyl bromide and sodium nitrite,
Quote:

from ethyl bromide (iodide) and sodium nitrite (dmf)
32.5 grams of ethyl bromide (0.3 moles) was poured into a stirred solution of 600ml dimethylformamide and 36 grams dry NaNO2 (0.52 mole) in a beaker standing in a water bath keeping the solution at room temperature as the reaction is slightly exothermic. Always keep the solution out of direct sunlight. The stirring was continued for six hours. After that, the reaction mixture was poured into a 2500 ml beaker or flask, containing 1500 ml ice-water and 100 ml of petroleum ether. The petroleum ether layer was poured off and saved, and the aqueous phase was extracted four more times with 100 ml of petroleum ether each, where after the organic extracts were pooled, and in turn was washed with 4x75ml of water. The remaining organic phase was dried over magnesium sulfate, filtered, and the petroleum ether was removed by distillation under reduced pressure on a water bath, which temperature was allowed to slowly rise to about 65°C. The residue, consisting of crude nitroethane was distilled under ordinary pressure (preferably with a small distillation column) to give 60% of product, boiling at 114-116°C.

The ethyl bromide reacts with NaNO2, forming nitroethane and ethyl nitrite.
This method can be varied in a few ways. Firstly, dimethyl sulfoxide (DMSO) can be substituted for the dimethylformamide (DMF) as solvent. Ethylene glycol also works as solvent, but the reaction proceeds pretty sluggishly in this medium, allowing for side reactions, such as this: RH-NO2 + R-ONO => R-(NO)NO2 + R-OH. KNO2 can also be used instead of NaNO2. If NaNO2 is used in DMF, 30g (0.5 mol) of urea can also be added as nitrite scavenger to minimize side reactions, as well as simultaneously increasing the solubility of the NaNO2 and thereby significantly speeding up the reaction.

If the ethyl bromide is substituted with ethyl iodide, the required reaction time is decreased to only 2.5 hours instead of 6 hours. In case ethyl iodide is employed, a slight change in the above procedure needs to be done. The pooled pet ether extracts should be washed with 2x75ml 10% sodium thiosulfate, followed by 2x75ml water, instead of 4x75ml water as above. This to remove small amounts of free iodine

Back to 5-AT preparation

NatashaJurievna - 5-2-2012 at 11:08

I'm surprised that no one mentions the Czechoslovakian patent no. 190055
http://spisy.upv.cz/Patents/FirstPages/FPPV0190/0190055.pdf



Translation of the text above:

164 grams of aminoguanidine sulfate were dissolved in 250 ml of hot 2,5N HCl. After the sulfate dissolved, the solution was cooled to 20 °C and 72 grams of NaNO2 in 100 ml of water were added dropwise at a temperature no more than 40 °C. When the nitrite solution was added, mixing was continued for 1 hour. Then 100 grams of sodium acetate were added, solution heated to boil and boiled for 20 minutes. After cooling, white crystals were filtered off and washed with a small amount of cold water.
Melting point 199 - 200 °C. Yield 69 g or 83% of the theoretical yield.
:cool:

[Edited on 5-2-2012 by NatashaJurievna]

mabuse_ - 17-2-2012 at 10:15

I just managed to get the starting materials for 5ATZ together and got my first batch ready.

http://www.wydawnictwa.ipo.waw.pl/cejem/2-2010/full/Sabate.p...

Has anyone here ever tried to reproduce the ethylenediamine compounds 3 and 4?
They seem to have the most desirable characteristics, ESD insensitive, extremely insensitive against shock & friction but apparently very sensitive to thermal shock.
To good to be true...

NatashaJurievna - 18-2-2012 at 12:01

Quote: Originally posted by mabuse_  
Has anyone here ever tried to reproduce the ethylenediamine compounds 3 and 4?
They seem to have the most desirable characteristics, ESD insensitive, extremely insensitive against shock & friction but apparently very sensitive to thermal shock.
To good to be true...


They seem to be interesting but I don't like somewhat the highly negative oxygen balance of the compounds. From the insensitive primary explosives based on tetrazole derivates I prefer the disilver aminotetrazole nitrate (double salt of silver nitrate and silver aminotetrazolate) though not cheap because of silver (good old 90's...).

mabuse_ - 20-2-2012 at 09:25

That's true.
To bad they did not deliver any performance figures.


Quote:

double salt of silver nitrate and silver aminotetrazolate

Do you have any data on that?

I find the price for the silver not that important, you don't want and don't need much anyway. Considering the rest of the raw materials the silver is a drop in the bucket;)

NatashaJurievna - 21-2-2012 at 07:39

Quote: Originally posted by mabuse_  
That's true.
To bad they did not deliver any performance figures.


Quote:

double salt of silver nitrate and silver aminotetrazolate

Do you have any data on that?

I find the price for the silver not that important, you don't want and don't need much anyway. Considering the rest of the raw materials the silver is a drop in the bucket;)


Where the nitrate is mentioned:
5-Aminotetrazoles and Silver-based Primary Explosives
While the nitrate is not as friction insensitive as the ethylenediamine nitrotetrazolate complexes and is sensitive to ESD, working with it is pretty safe in comparison with lead azide. I've not yet tested its initiating properties but seems to be a strong primary explosive. And yes, the silver is the more accessible part of the compound ;)
Is there any practical reason to nitration of ATZ, while it makes decent primary explosives? Ok, ok, I know. People are curious. I wonder if there are possible any usable ammonia/5-ATZ/Co(III) perchlorate or nitrite complexes.

Nitration of 5-methyltetrazole

AndersHoveland - 24-2-2012 at 07:28

Quote: Originally posted by AndersHoveland  
"...nitration of 5-methyltetrazole was attempted to afford 5-dinitromethylidene-1,4-dihydrotetrazole. But this reaction failed to proceed, and most of the starting material was recovered."

The reason that the nitration of 5-methyltetrazole failed to proceed is probably the same reason that nitration of plain 1,2,3-triazole is essentially impossible. I suspect that the electron-withdrawing tetrazole ring pulls away electric charge from the methyl group, giving it a partial positive charge and effectively shielding it from interaction with nitronium ions, which is the mechanism of reaction in most nitrations.


There is another route that could potentially be used to nitrate 5-methyltetrazole, by using a small quantity of N-hydroxyphthalimide as a catalyst:
Quote:

Catalytic nitration of alkanes with nitric acid was first successfully achieved by the use of N-hydroxyphthalimide (NHPI) under mild conditions; the key to the present nitration was found to be the in situ generation of NO2 and phthalimide N-oxyl radical by the reaction of NHPI with nitric acid.


http://pubs.rsc.org/en/content/articlelanding/2001/cc/b10237...
"Nitration of alkanes with nitric acid catalyzed by N-hydroxyphthalimide", Shinji Isozaki , Yoshiki Nishiwaki , Satoshi Sakaguchi and Yasutaka Ishii, Chem. Commun., 2001


The formation of intermediate radicals would bypass the charge shielding effect on the methyl group. As soon as the first nitro group is added, the molecule should then easily be able to undergo the normal nitration mechanism to add a second nitro group.

Quote:

nitromethyltetrazole could then be nitrated to give the final dinitromethyltetrazole product. 4-nitro-1,2,3-triazole, for example, can be readily nitrated to 4,5-dinitro-1,2,3-triazole.


If this works, an industrial process to this explosive compound could be fairly straightforward, using only acetamidine, hydrazine, nitrous acid [generated in reaction], nitric acid, and using NHPI as a catalyst.

see the diagram below:
DNMTrouteNHPI.GIF - 5kB

For the condensation of acetamidine with hydrazine (which displaces off ammonia), "Preparation of hydrazidines" US 4443629

This has already been extensively discussed elsewhere in this forum, but nitrous acid (from NaNO2 + HCl in solution) oxidizes aminoguanidine salts into guanyl azide N=N=N-C(=NH)NH2, which cyclizes into aminotetrazole (HN4C)NH2 when boiled under alkaline conditions. This takes several hours and gives 70-85% yield.

[Edited on 24-2-2012 by AndersHoveland]

AndersHoveland - 24-2-2012 at 16:51

Just compare the structure of 5-dinitromethyltetrazole (DNMT) to Fox-7, which is both powerful (more than RDX), and has a lower sensitivity. DNMT has two less hydrogen atoms (meaning better oxygen balance), and two more nitrogen atoms. The structure of DNMT is related to Fox-7, despite the fact that DNMT is also a tetrazole.

I do not know how sensitive DNMT is, but it is quite possible that DNMT may have a high enough resistance to impact to be used as a commercial/military explosive.

Fox-7 is about twice as resistant to impact as RDX. And Fox-7 has a detonation velocity of 8870 m/sec.

The nitrate salt of 5-aminotetrazole, for example, is both more powerful and less sensitive than RDX.

The detonation velocity for 5-nitrotetrazole is above 8.5 km/sec, and its sensitivity is 25cm.
V.A.Ostrovskii, G.I.Koldobskii, Russian Chemical Journal, 41, 84, (1997).

(for comparison, HMX is slightly more sensitive, with a drop height of 23cm) Most of the salts of 5-nitrotetrazole, however, are much more sensitive.

So looking at the properties of Fox-7 and some of the tetrazoles, it seems very probable that the sensitivity of DNMT is not too high. DNMT should be a very powerful explosive, the detonation velocity probably approaches 10 km/sec. Considering the predicted excellent performance, and low sensitivity DNMT would seem to hold much potential for practical application.

[Edited on 25-2-2012 by AndersHoveland]

Synthesis of acid copper 5-Nitrotetrazolate (CuNT)

fenolazul - 30-6-2012 at 14:20

Quote: Originally posted by Engager  
Synthesis of acid copper 5-Nitrotetrazolate (CuNT) from 5-aminotetrazole

Prepare solution 20.8g sodium nitrite and 11g of copper sulphate (CuSO4*5H2O) in 60 ml of hot water, resulting solution contains copper nitrite and has dark green color. Prepare solution of 10.3g aminotetrazole (ATZ) and 0.4g CuSO4*5H2O in 12.8 ml 70% nitric acid + 120 ml of water. Diazotetrazole is intermediate in nitrotetrazole synthesis, it can explode in solution if concentration will reach 2% from the slightless stimulus, even at 0C. Microexplosions are not dangerous but acting on nerves. To completely avoid them, slow addition, effective stiring and carefull temperature control are essential. Small adition of copper sulphate to ATZ solution is essential to avoid microexplosions in drops, on contact with nitrogen oxides, escaping from reaction mixture. Copper nitrite solution is placed on ice bath and cooled to 5C, then solution of ATZ in nitric acid, is added slowly with stirring (perfectly drop by drop). During addition temperature of reaction mixture must be kept below 15C all times. If mixture begins to foam, addition is paused and mixture is well stirred until foam dissapears before next portions of ATZ solution are added (foaming is result of HNO2 decomposition to water and NOx if it's concentration is too high). Reaction is proceeding smoothly, without microexplosions, with small evolution of NOx, if conditions are carefully controlled. Whole addition process takes time about 1.5 hours. Close to end of addition mixture becomes thicker, and changes color to green- blue (similar with homemade CuCO3*Cu(OH)2). After addition is completed mixture is left to sit in ice bath for 15 minutes, after that 14 ml of 70% nitric acid + 6 ml of water is added with stirring. Reaction mixture is left for 1 hour, solid precipitate of acid copper salt of nitrotetrazole is filtered off, washed with 5.72 ml HNO3 + 44 ml H2O and with three portions of 50 ml H2O. Yield is about 85%. Product is bluish - green crystals, almost insoluble in cold water.


Warning!!! Acid copper salt of nitrotetrazole is powerfull and sensitive explosive. It is almost completely safe then wet, but in dry state it can explode violently on friction, impact or heating. Safety precautions must be remembered all times.


Below are the photos of process. Left photo shows solutions of copper nitrite (left one) and ATZ in nitric acid with CuSO4 added (right one). Photo in the middle shows ice bath with sitting reaction flask, and termocouple temperature control. Right photo shows reaction product on filter.




Reaction sheme:



Acid copper salt of nitrotetrazole can be easily converted to soluble salts of nitrotetrazole by heating in solution of corresponding hydroxides. For example solution of sodium 5-nitrotetrazolate can be prepared by boiling acid copper salt in NaOH solution: Cu(NT)2*HNT + 3NaOH => 3NaNT + CuO+ 2H2O. Solid black copper oxide is removed by filtering, pure solution of NaNT can be concentrated to separate solid salt, or can be used dirrectly for further reactions.



[Edited on 14-9-2007 by Engager]


Quote: Originally posted by Engager  
Synthesis of acid copper 5-Nitrotetrazolate (CuNT) from 5-aminotetrazole

Prepare solution 20.8g sodium nitrite and 11g of copper sulphate (CuSO4*5H2O) in 60 ml of hot water, resulting solution contains copper nitrite and has dark green color. Prepare solution of 10.3g aminotetrazole (ATZ) and 0.4g CuSO4*5H2O in 12.8 ml 70% nitric acid + 120 ml of water. Diazotetrazole is intermediate in nitrotetrazole synthesis, it can explode in solution if concentration will reach 2% from the slightless stimulus, even at 0C. Microexplosions are not dangerous but acting on nerves. To completely avoid them, slow addition, effective stiring and carefull temperature control are essential. Small adition of copper sulphate to ATZ solution is essential to avoid microexplosions in drops, on contact with nitrogen oxides, escaping from reaction mixture. Copper nitrite solution is placed on ice bath and cooled to 5C, then solution of ATZ in nitric acid, is added slowly with stirring (perfectly drop by drop). During addition temperature of reaction mixture must be kept below 15C all times. If mixture begins to foam, addition is paused and mixture is well stirred until foam dissapears before next portions of ATZ solution are added (foaming is result of HNO2 decomposition to water and NOx if it's concentration is too high). Reaction is proceeding smoothly, without microexplosions, with small evolution of NOx, if conditions are carefully controlled. Whole addition process takes time about 1.5 hours. Close to end of addition mixture becomes thicker, and changes color to green- blue (similar with homemade CuCO3*Cu(OH)2). After addition is completed mixture is left to sit in ice bath for 15 minutes, after that 14 ml of 70% nitric acid + 6 ml of water is added with stirring. Reaction mixture is left for 1 hour, solid precipitate of acid copper salt of nitrotetrazole is filtered off, washed with 5.72 ml HNO3 + 44 ml H2O and with three portions of 50 ml H2O. Yield is about 85%. Product is bluish - green crystals, almost insoluble in cold water.


Warning!!! Acid copper salt of nitrotetrazole is powerfull and sensitive explosive. It is almost completely safe then wet, but in dry state it can explode violently on friction, impact or heating. Safety precautions must be remembered all times.


Below are the photos of process. Left photo shows solutions of copper nitrite (left one) and ATZ in nitric acid with CuSO4 added (right one). Photo in the middle shows ice bath with sitting reaction flask, and termocouple temperature control. Right photo shows reaction product on filter.




Reaction sheme:



Acid copper salt of nitrotetrazole can be easily converted to soluble salts of nitrotetrazole by heating in solution of corresponding hydroxides. For example solution of sodium 5-nitrotetrazolate can be prepared by boiling acid copper salt in NaOH solution: Cu(NT)2*HNT + 3NaOH => 3NaNT + CuO+ 2H2O. Solid black copper oxide is removed by filtering, pure solution of NaNT can be concentrated to separate solid salt, or can be used dirrectly for further reactions.



[Edited on 14-9-2007 by Engager]



Best regards from the hell.
I finally managed to synthesize this "magical" product: acid copper 5-Nitrotetrazolate (CuNT) from 5-AMINO-1H-TETRAZOLE MONOHIDRATO.

CuNT it is powerful and “green booster” primary explosive, following the valuable -step by step- instructions by Engager. Many thanks, master chemical!

But I have several questions, friends:

1º Once synthesized acid copper 5-Nitrotetrazolate, if it is stable for long periods of time. Years, even...?

2º Can be stored dry or always for safety must always be kept moist, immersed in distilled water and drying the exact amount to be used?

3º In the dry state is sensitive to hammer percussion?
(I have severely beaten the product between an anvil and a hammer and there is no outbreak)

4º Is sensitive to friction?

5º Is sensitive to static electricity?

6º Their contact is compatible with plastics materials, metals or metalloids without forming salts unstable or in contact with aluminum, steel, iron, antimony, etc. ... ?

7º Can be overpressed?

Finally and honestly, Engager/Sciencemadness friends, for personal experience: this powerfull compound is really stable and safe to handle?

I wish all the information possible about acid copper 5-Nitrotetrazolate , please.

Primary explosives handling, errors do not give second chances. :(

[Edited on 30-6-2012 by fenolazul]

[Edited on 30-6-2012 by fenolazul]

CuNTZ.jpg - 134kB

[Edited on 30-6-2012 by fenolazul]

Dry and ready for use.jpg - 126kB

[Edited on 30-6-2012 by fenolazul]

[Edited on 30-6-2012 by fenolazul]

fenolazul - 4-7-2012 at 07:32

Any information to acid copper 5-Nitrotetrazolate (CuNT) from 5-AMINO-1H-TETRAZOLE MONOHIDRATO?

No expert has nothing to say? :(

[Edited on 4-7-2012 by fenolazul]

[Edited on 4-7-2012 by fenolazul]

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