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Author: Subject: 5-azidotetrazole synth gone horribly wrong
IPN
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sad.gif posted on 14-1-2006 at 06:31
5-azidotetrazole synth gone horribly wrong


Ok.. about 5 minutes ago I formed a hazardous situation while testing the preparation of 5-azidotetrazole from tetrazene doing the following:

0,50g tetrazene in the form of light yellow fluffy needles (I know, I should have tried with much smaller amounts..) was added to a warm and stirred (~50C) solution of 2,00g NaOH in a test tube. This produced a very light yellow solution and an immediate ammonia smell (NaOH causes the tetrazene to hydrolyse into ammonia, cyanamide and triazonitrosoaminoguanidine). I placed the test tube into a hot water bath (~90C) to expel some of the ammonia while I prepared a saturated solution of copper acetate from CuO and 100% HOAc (this is where I made an error, I used a bit too much acetic acid and produced an acidic solution of copper acetate which the instantly precipitated the azidotetrazole). To the stirred solution in the test tube was then added slowly some of the Cu(OAc)2 solution and an odd brown/black precipitate formed instead of the expected blue precipitate. I decided to test the pH of the soln. and proceeded to take a sample with a glass rod. As I was putting the glass rod into the solution a violent detonation ensued which broke the bottom of the test tube into tiny fragments and cracked the 600ml beaker I used as the water bath. The detonation also sprayed the reaction mixture with the precipitate all over the place. Strong crackling continued in the beaker as I ran out of the garage...

A little later when I returned small snap/crack sounds were caused by me simply walking in the garage. :o Any ideas on how to clear the mess and/or move the beaker without getting myself killed/injured? :( I’ll go and take few pictures as soon as the crackling in the garage quiets down a bit.. :o

Here are the pics:

http://koti.mbnet.fi/otto2000/P1140091.JPG
http://koti.mbnet.fi/otto2000/P1140092.JPG
http://koti.mbnet.fi/otto2000/P1140093.JPG
http://koti.mbnet.fi/otto2000/P1140094.JPG
http://koti.mbnet.fi/otto2000/P1140095.JPG


[Edited on 14.1.2006 by IPN]
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[*] posted on 14-1-2006 at 11:14


Holy shit, that is not very nice IPN, those things cost a week of one's life...:(

I don't know anything about azidotetrazole, but it might be worth to look up under which conditions it is degraded, (acidic, lye, oxidated, reduced?) so you can carefully add a reagent to the beaker...
Moody HE's in a glass beaker are not funny at all...

Good luck, you'll need it...




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[*] posted on 14-1-2006 at 11:23


IPN, can you tell to the uninitiated what exactly you were trying to do, why adding Cu salt, why heating, and why decomposing it?

From what I understand you used this compound





and decomposed it to what precisely?

What is the blue precipitate you'd normally expect?

[Edited on 15-1-2006 by chemoleo]




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IPN
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[*] posted on 14-1-2006 at 11:48


Oh yes, I forgot to tell about the reaction.

Found the procedure in COPAE (page 447) and it basically just says that tetracene hydrolyses with caustic soda to ammonia, cyanamide and triazonitrosoaminoguanidine, which can then be isolated as the copper salt (bright blue precipitate) by the addition of copper acetate. The copper salt on treatment with acid will then yield 5-azidotetrazole. Also the heating part to expel the ammonia was probably quite useless.. Just thought to get it off the solution so the copper wouldn't form a complex with it.

I placed some tissue paper around the stirrer to keep the solution with the suspended azide from flowing on the floor. I have also sprayed the papers wet so that they won't so easily detonate the precipitate if moved afterwards. Luckily most of the precipitate is in the bottom of the beaker, though I'm not sure if just only copper oxide.. Anyone have solubility data for 5-azidotetrazole?

[Edited on 14.1.2006 by IPN]

Mick:
I didn't buy the tetracene and considering it is a primary explosive already on it's own I don't think one can buy it anywhere. It was made from aminoguanidine by the method found in COPAE (Chemistry of Powder and Explosives that is).

[Edited on 14.1.2006 by IPN]
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[*] posted on 14-1-2006 at 13:49


I assume you bought the tetracene over the counter.

mick

An azidotetrazole just sounds too stupid to me unless on milligram quantities.

mick

Do not heat it

mike

[Edited on 14-1-2006 by mick]

[Edited on 14-1-2006 by mick]
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[*] posted on 14-1-2006 at 16:39


Er? Tetracene is four fused aromatic rings? That doesn't sound very explosive, nor that it would hydrolyze to anything with nitrogen. Do you mean tetrazene?

Geez, both of these terms are pretty poopy... Wikipedia has the scoop though, as always.
<I>"Tetrazene, also called tetrazine, tetracene, or 1(5-tetrazolyl)-4-guanyl tetrazene hydrate, is an explosive material, used as an initiator."</I>

Tim




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[*] posted on 14-1-2006 at 17:35


Sigh... what do you think why I posted the structure above?
To precisely prevent some goons posting several posts on diet pills :o
Much good it did. Mick, next time switch on your brain before you start posting.


Here's the method for preparation of 1-guanyl-4-nitrosoaminoguanyltetrazene.

Anyway, yes, IPN it looks like you may have caused an adverse reaction with too much acid. It actually says in COPAE that other products are made, and who knows what funny salts could be made with copper.

[Edited on 15-1-2006 by chemoleo]




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[*] posted on 14-1-2006 at 18:55


chemelo, FYI, I don't know if this is a problem for anyone else, but the embedded gif's do not show up in my browser, only the broken picture icon. I'm using IE on Windows, BTW.
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[*] posted on 15-1-2006 at 04:46


From bretherick:

<i>0388. 5-Azidotetrazole [35038-46-1] CHN7
Alone, or Acetic acid, or Alkali
1. Thiele, J. et al., Ann., 1895, 287, 238
2. Lieber, E. et al., J. Amer. Chem. Soc., 1951, 73, 1313
Though explosive, it (and its ammonium salt) are much less sensitive to impact or friction than its sodium or potassium salts [1]. A small sample of the latter exploded violently during vacuum filtration. The parent compound explodes spontaneously even in acetone (but not in ethanol or aqueous) solution if traces of acetic acid are present [2]. The salts are readily formed from diaminoguanidine salts and alkali nitrites. The ammonium salt explodes on heating, and the silver salt is violently explosive even when wet [1]. The sodium salt is also readily formed from cyanogen azide.
See Sodium 5-azidotetrazolide
See other ORGANIC AZIDES, TETRAZOLES</i>

Note the reference to acetic acid. Perhaps they need to re-write the "but not in aqueous solution" comment. With the word "traces" perhaps one should keep acetic/acetates as far away from it as possible.
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[*] posted on 15-1-2006 at 06:55


Quote:
Originally posted by zoomer
chemelo, FYI, I don't know if this is a problem for anyone else, but the embedded gif's do not show up in my browser, only the broken picture icon. I'm using IE on Windows, BTW.


Ditto. Sorry I forgot to mention that image isn't working.




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[*] posted on 15-1-2006 at 09:08


The comment above was from personal experience. I know an organic azide is "safe" at a low level. I also know some one scaled it up and ended up on fire. Add an azide to the tetrazole ring seems to me like adding a detonator to an explosive on a molecular level.

mick

I will try and get my brain up to speed

mick

[Edited on 15-1-2006 by mick]
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[*] posted on 16-1-2006 at 05:13


Quote:
Originally posted by IPN
Ok.. about 5 minutes ago I formed a hazardous situation while testing the preparation of 5-azidotetrazole from tetrazene doing the following:

0,50g tetrazene in the form of light yellow fluffy needles (I know, I should have tried with much smaller amounts..) was added to a warm and stirred (~50C) solution of 2,00g NaOH in a test tube. This produced a very light yellow solution and an immediate ammonia smell (NaOH causes the tetrazene to hydrolyse into ammonia, cyanamide and triazonitrosoaminoguanidine). I placed the test tube into a hot water bath (~90C) to expel some of the ammonia while I prepared a saturated solution of copper acetate from CuO and 100% HOAc (this is where I made an error, I used a bit too much acetic acid and produced an acidic solution of copper acetate which the instantly precipitated the azidotetrazole). To the stirred solution in the test tube was then added slowly some of the Cu(OAc)2 solution and an odd brown/black precipitate formed instead of the expected blue precipitate. I decided to test the pH of the soln. and proceeded to take a sample with a glass rod...

Do you neutralize the solution of tetrazene before adding Cu(OAc)2 and was the resulting mixture acidic? There is a mention, that the OH- hydrolysed tetrazene tends to self-ignition in vacuum under H2SO4. Probably, during hydrolyzis HCN4N3 forms from intermediate HN4CN2NHNH2 => HN4CN3+NH4(+). That's why, the solution may contain, for example, different diazotetrazol derivatives also. Some of their Cu-salts even more unstable, then CN7(-)-salt.
To prepare AgCN7 from OH-tetrazen solution, it was initially neutralized with weak HNO3 and then added to excess of AgNO3-solution (Ag-salt of cyanamid was extracted from resulting precipitate by weak NH4OH).
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[*] posted on 16-1-2006 at 11:50


Yikes!

Perhaps using the synthesis from aminotetrazole and amylnitrite would be safer...

Did you let the solution cool back to room temperature before the Cu(OAc)2 was added, or was it still hot/warm?

Quote:
an odd brown/black precipitate formed instead of the expected blue precipitate.

From this it seems to be that you formed some extremely explosive copper salts. Copper salts of tetrazoles make powerful initiators, and if the solution was hot at the time...

To move the beaker, put on hearing protection/eye protection, and throw things at it from the door, ducking behind each time to avoid shrapnel if it explodes. (note: this is incredibly unsafe, but if the floor snaps from you walking then it may be your only option! I would not want to approach the beaker without heavy protection if it is that unstable) If it doesn't explode it's probably safe to clean up using water. You might be able to push the broken beaker into a large bucket of water, if it explodes then you will be safe, if not then it is diluted and you can destroy whatever it is you made.
Reduce the solution with Zn/HCl to turn it into aminotetrazole which is non-explosive. This should also reduce other nitrogen compounds to amino etc... Perhaps hydrogen peroxide/acid could be added afterwards to oxidize anything left. And add sulfuric acid to form copper sulfate and prevent the existance of potentially dangerous copper salts.
Then it should be safe to flush away diluted.

That is what I would do, chances are someone else has a much safer and easier solution.
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[*] posted on 17-1-2006 at 09:14


Artem:
No I didn’t neutralize the solution, this probably resulted in large amounts of CuO as the black precipitate and yes, the mix was acidic after the addition. Around pH 5 IIRC.

Chris The Great:
Yeah, I won’t be trying this method anymore.. :P

The solution was allowed to cool a bit but was probably still around ~50C

I cleared the situation by placing a plastic bucket over the magnetic stirrer (there was the stirbar from the test tube in the beaker), turning it on full and switching on the power with the aid of a long power cord. This caused the remaining sensitive tetrazole derivatives to detonate in a confined manner. There wasn’t much remaining as it only shattered the beaker in few pieces..

Finally I can continue working in the lab. :)
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[*] posted on 19-1-2006 at 02:21


This reminds me the unstability of copper trihydrazine dinitrate...
Pale blue precipitate after a few trials ... but mostly brown-black precipitate and N2 evolution. Spontaneous ignition was observed.

Parallelism with your experience seems to match except you got detonation...




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[*] posted on 19-1-2006 at 05:25


Chris, aminotetrazole and a nitrite will give a diazonium salt, CHN6(+). Heating this at 80*C gives a diazo compound, CN6, which loses nitrogen first to give a carbene, :CN4, then more nitrogen to give a carbon atom. However,

"It should be emphasised that [the diazonium salt] is extremely explosive and should be handled with great care. We recommend that no more than 0.75 mmol be isolated at one time. Ethereal solutions are somewhat more stable but explosions have occured after standing at -70*C for 1 hr."

The azidotetrazole should be nicer, but to get it using a nitrite you would need tetrazolylhydrazine. I wonder if you could get that using aminotetrazole and hydrazine, like in aminoguanidine and semicarbazide synths from guanidine and urea, respectively. Or aminotetrazole and chloramine....
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[*] posted on 19-1-2006 at 08:03


Check Propellants, Explosives, Pyrotechnics vol 30 page 17. There is described the synthesis of azidotetrazole starting from aminotetrazole, isoamylnitrite and HCl to form the diazonium salt and then reacting that with sodium azide. I believe this is what Chris was referring to.
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[*] posted on 19-1-2006 at 08:34


Ah yes, of course!!

No copper catalyst..?
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smile.gif posted on 27-8-2007 at 11:09


Quote:
[quote
The azidotetrazole should be nicer, but to get it using a nitrite you would need tetrazolylhydrazine. I wonder if you could get that using aminotetrazole and hydrazine, like in aminoguanidine and semicarbazide synths from guanidine and urea, respectively. Or aminotetrazole and chloramine....


That's relatively easy, just oxidise 5-aminotetrazole with excess of KMnO4 in presence of large amounts of NaOH. After add alcohol to remove excess of KMnO4, boil 1h and filter solution from MnO2, evaporate to smaller volume and cool to form sodium 5,5'-azotetrazolate (i've made one by this method). Free 5,5'-azotetrazole is unstable if you add 2 moles HCl to 1 mole sodium 5,5'-azotetrazolate, it will result of formation of tetrazylhydrazine formic acid and nitrogen yield is close to 100%. You can diazotate it in usual manner to get solution of tetrazylazide. ;)
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[*] posted on 31-1-2008 at 21:24


sodium 5-azidotetrazolate
"...the dry salt is extremely sensitive to friction, heat, electrical shock, and pressure. For example a dry sample at 1mm pressure will usually detonate if brought rapidly to atmospheric pressure. Great care and adequate protective equipment(shields, leather gloves and jacket) should be used when preparing even small quantities of the dry compound. Samples larger than 0.1 g are best handled remotely. The salt can be prepared and handled safely in aqueous solution or as a free flowing solid when moistened with water or mixed with an equal weight of mineral oil. We have prepared acetone solutions without event, but Lieber reports that solutions containing traces of acetic acid may detonate and in this respect our procedure is safer[from cyanogen azide and NaN3]. Pure dry 5-azidotetrazole is less sensitive than its sodium salt but the same handling precautions apply. Ammonium-5-azidotetrazole is still less sensitive to shock but detonates when heated rapidly to ~190C."

This sounds worse than silver fulminate:o

From J. Org. Chem., Vol.37, No 19, 1972, 2966

I can't imagine 0.5 g as IPN had in the infamous sensitizing acetic acid solution, with the heavy metal copper salt present

[Edited on 31-1-2008 by The_Davster]
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[*] posted on 29-9-2015 at 17:08


Quote: Originally posted by IPN  
Ok.. about 5 minutes ago I formed a hazardous situation while testing the preparation of 5-azidotetrazole from tetrazene doing the following:

0,50g tetrazene in the form of light yellow fluffy needles (I know, I should have tried with much smaller amounts..) was added to a warm and stirred (~50C) solution of 2,00g NaOH in a test tube. This produced a very light yellow solution and an immediate ammonia smell (NaOH causes the tetrazene to hydrolyse into ammonia, cyanamide and triazonitrosoaminoguanidine). I placed the test tube into a hot water bath (~90C) to expel some of the ammonia while I prepared a saturated solution of copper acetate from CuO and 100% HOAc (this is where I made an error, I used a bit too much acetic acid and produced an acidic solution of copper acetate which the instantly precipitated the azidotetrazole). To the stirred solution in the test tube was then added slowly some of the Cu(OAc)2 solution and an odd brown/black precipitate formed instead of the expected blue precipitate. I decided to test the pH of the soln. and proceeded to take a sample with a glass rod. As I was putting the glass rod into the solution a violent detonation ensued which broke the bottom of the test tube into tiny fragments and cracked the 600ml beaker I used as the water bath. The detonation also sprayed the reaction mixture with the precipitate all over the place. Strong crackling continued in the beaker as I ran out of the garage...

A little later when I returned small snap/crack sounds were caused by me simply walking in the garage. :o Any ideas on how to clear the mess and/or move the beaker without getting myself killed/injured? :( I’ll go and take few pictures as soon as the crackling in the garage quiets down a bit.. :o

Here are the pics:

http://koti.mbnet.fi/otto2000/P1140091.JPG
http://koti.mbnet.fi/otto2000/P1140092.JPG
http://koti.mbnet.fi/otto2000/P1140093.JPG
http://koti.mbnet.fi/otto2000/P1140094.JPG
http://koti.mbnet.fi/otto2000/P1140095.JPG


[Edited on 14.1.2006 by IPN]



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[*] posted on 30-9-2015 at 06:15


This was posted almost 10 years ago. IPN remained posting to SM for another 8 years after this happened. My guess is that he's fine. :)



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