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Author: Subject: 5-ATZ(5-Aminotetrazole), the nitrotetrazolate ion and friends
Rosco Bodine
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biggrin.gif posted on 14-6-2011 at 18:20
azidoformamidinium 3,5-dinitro-1,2,4-triazole


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]
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AndersHoveland
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[*] posted on 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.




I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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Rosco Bodine
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[*] posted on 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]
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[*] posted on 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]




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Rosco Bodine
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[*] posted on 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]
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[*] posted on 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]




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Rosco Bodine
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[*] posted on 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]
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[*] posted on 23-6-2011 at 23:41
azobisformamidine salts


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]
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[*] posted on 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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[*] posted on 12-7-2011 at 10:30
Guanidine to aminotetrazole


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
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[*] posted on 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)
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Rosco Bodine
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[*] posted on 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
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[*] posted on 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.
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[*] posted on 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.
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Rosco Bodine
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[*] posted on 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]
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[*] posted on 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.



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[*] posted on 13-7-2011 at 18:26
diazoguanidine freebase reportedly stable ?


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]
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[*] posted on 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]
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Rosco Bodine
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[*] posted on 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.
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[*] posted on 15-7-2011 at 14:36




[Edited on 16-7-2011 by Engager]

tetrazole.jpg - 124kB




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[*] posted on 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.
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Rosco Bodine
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[*] posted on 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]
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[*] posted on 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]




I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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[*] posted on 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]
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[*] posted on 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]




I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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