Sciencemadness Discussion Board

New Energetic Materials - Current Research

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Microtek - 28-10-2021 at 07:48

@katyushaslab

I did see that entry in Ullmann, but everywhere else I have looked, people are diethyl- or dimethyl-carbonate instead of urea. In the end, I have decided to buy some dimethyl carbonate to see if I can synthesize some carbohydrazide, and then urazine.


@Fulmen

If you have NaClO4 and a glass frit funnel it is also very easy. You just add dried NaClO4 to 37% HCl. The NaCl produced is almost insoluble in the acid and precipitates out. Then you run it through the glass frit (or you could decant if you don't mind losing some) and distil the HCl off. I found this process in a paper, and the authors had found that it gives a highly pure product with good efficiency. I have made 50% HClO4 this way, and found it to be completely free of chloride. As a bonus, any chlorate in your perchlorate is destroyed.

katyushaslab - 28-10-2021 at 13:40

@Microtek: I found some mentions that semicarbazide will react further with hydrazine to form carbohydrazide. Semicarbazide can be prepared easily - though you know that, as its your writeup from 2002 that I found on the matter from the E&W forum archive [0]. A relevant patent for semicarbazide to carbohydrazide is DE2112398A1 [1].

From the patent, apparently refluxing 5.57g semicarbazide hydrochloride with 7.5g hydrazine hydrate were refluxed for 6 hours with a yield of 3.4g, which is apparently around 75%.

[0]: https://www.thevespiary.org/rhodium/Rhodium/www.roguesci.org...
[1]: https://patents.google.com/patent/DE2112398A1/en

[Edited on 28-10-2021 by katyushaslab]

Microtek - 28-10-2021 at 23:01

Good find, that makes it much more OTC (I had forgotten all about that experiment). For those of us without access to modern analytic methods, it's always nice with a few different synthetic routes - if the products several such routes appear identical, there's a decent likelyhood that it is the one you were aiming for.

MineMan - 29-10-2021 at 00:45

Carbohydrazide is cheap and very available. Many members have it due to the DAUN experiment. More than they would want. I suggest that several would probably be willing to ship.

The issue I have with the Urazine perchlorate is the sensitivity. It’s that of a primary explosive. With a sensitivity of 2J and 28N, I wouldn’t want to plasticize it either. This may indeed be a primary explosive, based on sensitivity I would say it will DDT in a closed tube. It’s very disappointing, that the sensitivity is so high, to me, this rules out and experiment using more than 5 grams. This would be the perfect EM for shaped explosives, I hate to be cyclical, but as is often the case, HDEM disappoint.

Microtek - 29-10-2021 at 10:05

PETN has an impact sensitivity of 3.6J, mannitol hexanitrate 0.8-1.8 J. I couldn't find data for ETN, but I would guess around 2J. Definitely too sensitive for the military, but I wouldn't worry too much in a laboratory setting.

katyushaslab - 29-10-2021 at 10:17

PETN is regarded as the "boundary" between primary and secondary in the modern literature. Interestingly, impact values do seem to vary lab to lab.

https://pubs.acs.org/doi/10.1021/acsomega.1c01115

Belowzero - 29-10-2021 at 11:35

Quote: Originally posted by katyushaslab  
PETN is regarded as the "boundary" between primary and secondary in the modern literature. Interestingly, impact values do seem to vary lab to lab.

https://pubs.acs.org/doi/10.1021/acsomega.1c01115


I think this is mostly from a military perspective, it is understandable that its kinda problematic to drop a 500lb device on the deck of a ship and having it explode.
They certainly have a point but to be honest I have handled this material quite often and it is remarkably difficult to get it to do anything, even lighting a stove with it is a pain in the ass.

This does not mean that it does not deserve the utter most respect knowing the damage even a small amount can do.
However, the level of care that I practise is anything but common in the real world, that and the quantity.

MHN requires a heavy heavy hammer blow too, iirc its only once I got it to detonate by impact.



[Edited on 29-10-2021 by Belowzero]

[Edited on 30-10-2021 by Belowzero]

MineMan - 29-10-2021 at 18:15

Hmm. I have noticed with hammers, holding it at a slight angle or a rough surface makes all the difference. But that’s besides the point. Is there any way to make this without perchlorate acid… rather a replacement with ammonium perchlorate. They didn’t give data on if it’s melt cast. None the less, what’s the highest amount you can add a powdered explosive to a melt cast one? I hear 80 percent with no air bubbles.

Yes, PETN is more friction resistant. But. This is one synth. Controlling the crystal size or even coating should help. Much work to be done.

MineMan - 29-10-2021 at 19:47

It didn’t mention the exact synth. But did say crystals were .5-1mm. If they are reduced, sensitivity should improve.

Any way to do a replacement with ammonium perchlorate or another, instead of the acid.

MineMan - 11-11-2021 at 15:50

Quote: Originally posted by Microtek  
PETN has an impact sensitivity of 3.6J, mannitol hexanitrate 0.8-1.8 J. I couldn't find data for ETN, but I would guess around 2J. Definitely too sensitive for the military, but I wouldn't worry too much in a laboratory setting.


I looked up my favorite primary. It has a impact value of 4J and friction of 20. About a tie with this compound. The issue, being a secondary, charges of interest would need to be 50 grams. Do you think it’s safe to make that much in one pot with no worries? All hypothetical. The wise thing would be to coat the material with 1-5 percent wax. PETN is safely used in det cord. But it’s friction value is 120N, not the 28.

Any update on if it can be pronated using displacement of another perchlorate.

Microtek - 12-11-2021 at 14:15

Well, my charges are rarely more than 1 gram secondary (hence my moniker), so a potential accident would be less catastrophic. Having said that, one of the things I enjoy about this hobby, is the engineering aspect of it. It will be interesting to see how the sensitivity can be modified by adding polymers or other binders, and how that will affect performance. I will post in this thread when I have something to report.

MineMan - 12-11-2021 at 22:28

Quote: Originally posted by Microtek  
Well, my charges are rarely more than 1 gram secondary (hence my moniker), so a potential accident would be less catastrophic. Having said that, one of the things I enjoy about this hobby, is the engineering aspect of it. It will be interesting to see how the sensitivity can be modified by adding polymers or other binders, and how that will affect performance. I will post in this thread when I have something to report.


I look forward to it. Can the perchlorate be made by meta thesis by another perchlorate such as ammonium perchlorate?? Please let me know.

You plan on making this compound? I am almost certain the sensitivity can be lessened.

Microtek - 23-11-2021 at 07:26

Ok, so I've synthesized what I believe to be urazine.

I began from dimethylcarbonate and followed "Green Synthetic Method for1,5-Disubstituted Carbohydrazones" by Li et al.

Thus dimethylcarbonate (9g, 0.1 mol) was mixed with hydrazine hydrate (5.5 g, 0.11 mol) in a small two-necked flask fitted with reflux coloumn and thermometer adapter and heated with stirring to 70C. The mix was held at this temp (with constant stirring) for 4 hrs.
Then the reflux coloumn was replaced with a distillation head, and a small amount of liquid was distilled off under reduced pressure. I think most of the liberated methanol had probably escaped through the reflux coloumn, or else weren't condensed in the cooler in this step.
After cooling down, more hydrazine hydrate (11 g, 0.22 mol) was added, and the mix was stirred at 70C for another 4 hrs (with reflux coloumn).
Then the distillation head was attached again, and the mix was concentrated under reduced pressure until a white precipitate began to form.
Heating was stopped, and once cooled, the reaction mixture was filtered to recover the crude product, which should be carbohydrazide. The product consisted of large, stocky crystals and after washing with a little water and drying overnight, it weighed 6,77 g, corresponding to ca. 75% yield.

To synthesize urazine, the method from "Inorganic Synthesis" (vol 4, p 30-31) was followed. I had the problem that the small amounts of material (6.77 g carbohydrazide and 7 ml HCl, 12M) didn't allow me to effectively monitor the temperature. I used an IR thermometer, but couldn't get very consistent readings. The procedure calls for slowly raising the temp. There should be a plateau around 215C which it should hold for about an hour. Then, when the temp increases to above 220C, heating is stopped and the reaction is allowed to cool.
Then water (8 ml) is added, and the reaction is heated to dissolve byproduct hydrazine*HCl. The product, urazine, is not very soluble in water (0.32 g in 100 ml at 0C) so isolation is easy.
After washing and drying, 1.878 g crude product was obtained. I recrystallized it from 0.1M HCl as outlined in the litterature, but I'm not sure it was necessary; the melting point didn't seem to change much. Anyway, after recrystallization, I was left with 1.548 g urazine (assuming that is what it is - solubilities and melting point corroborate the assumption, but I haven't tried any other methods of analysis).

The total yield is just 26.6 % based on dimethylcarbonate, and less based on hydrazine hydrate. This is still enough for doing some testing since it should give about 2.6 g urazine perchlorate given the yield from the Klapötke paper. However, I don't like this procedure since it is uses quite a lot of hydrazine. I find this problematic, both because of the expense and the potential health effects (I do work in a fume hood, but accidents do happen).




MineMan - 23-11-2021 at 21:54

Quote: Originally posted by Microtek  
Ok, so I've synthesized what I believe to be urazine.

I began from dimethylcarbonate and followed "Green Synthetic Method for1,5-Disubstituted Carbohydrazones" by Li et al.

Thus dimethylcarbonate (9g, 0.1 mol) was mixed with hydrazine hydrate (5.5 g, 0.11 mol) in a small two-necked flask fitted with reflux coloumn and thermometer adapter and heated with stirring to 70C. The mix was held at this temp (with constant stirring) for 4 hrs.
Then the reflux coloumn was replaced with a distillation head, and a small amount of liquid was distilled off under reduced pressure. I think most of the liberated methanol had probably escaped through the reflux coloumn, or else weren't condensed in the cooler in this step.
After cooling down, more hydrazine hydrate (11 g, 0.22 mol) was added, and the mix was stirred at 70C for another 4 hrs (with reflux coloumn).
Then the distillation head was attached again, and the mix was concentrated under reduced pressure until a white precipitate began to form.
Heating was stopped, and once cooled, the reaction mixture was filtered to recover the crude product, which should be carbohydrazide. The product consisted of large, stocky crystals and after washing with a little water and drying overnight, it weighed 6,77 g, corresponding to ca. 75% yield.

To synthesize urazine, the method from "Inorganic Synthesis" (vol 4, p 30-31) was followed. I had the problem that the small amounts of material (6.77 g carbohydrazide and 7 ml HCl, 12M) didn't allow me to effectively monitor the temperature. I used an IR thermometer, but couldn't get very consistent readings. The procedure calls for slowly raising the temp. There should be a plateau around 215C which it should hold for about an hour. Then, when the temp increases to above 220C, heating is stopped and the reaction is allowed to cool.
Then water (8 ml) is added, and the reaction is heated to dissolve byproduct hydrazine*HCl. The product, urazine, is not very soluble in water (0.32 g in 100 ml at 0C) so isolation is easy.
After washing and drying, 1.878 g crude product was obtained. I recrystallized it from 0.1M HCl as outlined in the litterature, but I'm not sure it was necessary; the melting point didn't seem to change much. Anyway, after recrystallization, I was left with 1.548 g urazine (assuming that is what it is - solubilities and melting point corroborate the assumption, but I haven't tried any other methods of analysis).

The total yield is just 26.6 % based on dimethylcarbonate, and less based on hydrazine hydrate. This is still enough for doing some testing since it should give about 2.6 g urazine perchlorate given the yield from the Klapötke paper. However, I don't like this procedure since it is uses quite a lot of hydrazine. I find this problematic, both because of the expense and the potential health effects (I do work in a fume hood, but accidents do happen).





Why not just buy carbohydrazide, or if in the US I can send you 50 grams. If it is Urazine it should be a VERY dense organic molecule at 2.4g/cc. That could be a way to find out.

Microtek - 24-11-2021 at 02:02

I'm in the EU, and haven't been able to find carbohydrazide locally. Importing from outside the EU is quite expensive due to customs and administrative fees. At any rate, this is a chemistry forum, and I enjoy the lab work.
If one were to require more than a few grams, buying carbohydrazide would certainly be the way to go. Also, in the condensation reaction where two molecules of carbohydrazide form one of urazine, two molecules of hydrazine are expelled (as the HCl salt). Some of this is probably decomposed at the reaction temperature but according to the writeup in "Inorganic Synthesis", most of the byproduct is hydrazine*HCl. Since urazine is easily separated, I was thinking that maybe the hydrazine could be recovered by precipitating as the bisulfate. If all the biproduct hydrazine could be recovered this way, you would get 2.24 gram of hydrazine sulfate for each gram of urazine produced, perhaps making this a viable route to HS.

katyushaslab - 24-11-2021 at 04:51

Being able to recover some hydrazine (as sulphate) and feed it forward into other reactions is a very interesting possibility, especially for waste management.

MineMan - 24-11-2021 at 16:09

How would you break the hydrazine chloride into hydrazine sulfate?! Could this be done via a one pot reaction?

How can Urazine really be 2.4g/cc. I know of no other organic molecule with such a density.

Microtek - 24-11-2021 at 23:10

That is a predicted value using the ACDlabs software. ACDlabs is notorious for overestimating the density of organic molecules, so I am quite certain the actual density is somewhat lower. In fact, I would be extremely surprised if urazine isn't less dense than the perchlorate salt.

Hydrazine*HCl to sulfate is a simple metathesis reaction, and is driven by the precipitation of low solubility hydrazine bisulfate. I would simply add 50% sulfuric acid (possibly even sodium sulfate) directly to the filtrate after filtering off the urazine, then filtering off the formed HS.

MineMan - 25-11-2021 at 14:25

Quote: Originally posted by Microtek  
That is a predicted value using the ACDlabs software. ACDlabs is notorious for overestimating the density of organic molecules, so I am quite certain the actual density is somewhat lower. In fact, I would be extremely surprised if urazine isn't less dense than the perchlorate salt.

Hydrazine*HCl to sulfate is a simple metathesis reaction, and is driven by the precipitation of low solubility hydrazine bisulfate. I would simply add 50% sulfuric acid (possibly even sodium sulfate) directly to the filtrate after filtering off the urazine, then filtering off the formed HS.


I was wondering how the perchlorate salt was less dense! Could you do a density test for us?!

Seems to be a very beneficial reaction… big question is can you make the perchlorate salt via meta thesis?

Microtek - 26-11-2021 at 02:10

I'm fairly certain that metathesis won't work to produce urazine perchlorate. The urazine is a very weak base, and even with HClO4 the salt is only formed on heating.

MineMan - 26-11-2021 at 02:19

Quote: Originally posted by Microtek  
I'm fairly certain that metathesis won't work to produce urazine perchlorate. The urazine is a very weak base, and even with HClO4 the salt is only formed on heating.


Why is it possible with aminoguanidine?

What percentage of perchloric is needed… wouldn’t a nitrate salt be almost as high performing?

Microtek - 22-12-2021 at 09:47

My experiments with urazine are on hold, since I have come to doubt the identity (or maybe purity) of the compound I had synthesized. It seems I will have to buy some after all.

In the mean time, I have been experimenting with some 4-amino-1,2,4-triazole that I ordered some years ago to test the capability of a supplier. I was searching for candidates for melt castable explosives, and wanted to try some aminotriazole compounds. I had some limited success with the picrate salt IIRC, but in the end I put it on indefinite hold.
However, the urazine salts inspired me to make some more tests. The nitrate and perchlorate salts are both energetic as would be expected, but the nitrate is not reliably initiated in my setup. It may possibly be of interest as a less sensitive explosive.
The perchlorate salt is much more sensitive, and seems to propagate detonation very effectively. My initial sensitivity tests involve a rapid cook-off test, a hammer test and a friction test. In the cook-off test, 50 mg ATrzP melts, bubbles and finally "pops" with enough force to make a large hole in the Al foil it is held on. It doesn't detonate though. ATrzN just burns with a hissing flame. In the hammer test 50 mg ATrzP is easily set off with moderate hammer blows, and detonates with a loud report and a VERY bright flash. The explosion is reminiscent of a drop of NG on tissue paper, in that it seems to be the entire mass of explosive that detonates (often, these tests will only set off parts of the explosive, and successive blows can achieve more detonations). ATrzN is only set off with difficulty in the hammer test. I wasn't able to initiate either of them by rubbing between hammer and anvil, but AtrzP gave a (very) positive reaction in my oblique impact test, which is a steel pendulum drop hammer which impacts a steel surface at a 25 degree angle from horizontal. The pendulum can be released from varying heights and the sample can be placed directly on the steel anvil or on a small piece of fine grit sand paper. In this test, ATrzP gave a positive test (any sign of chemical decomposition) at a slightly lower height than PETN, but did so more reliably. PETN often does not explode, but decomposition can be detected by smell. ATrzP usually explodes with flame and a clearly audible report.

I also tested performance in the manner that I described under the "NHN without hydrazine hydrate" thread. I didn't press it very much because of the insufficiently tested sensitivity, but at a density of only 1.55 g/cc, the dent in aluminum bar stock was on par with that of HMX at >1.8 g/cc. If I can tame the sensitivity of the material (inert binders, perchlorate/nitrate mixes or other methods) it could be an interesting avenue of research.

I experimented with two different methods of preparation: One was straight forward reaction of 4-amino-1,2,4-triazole with HClO4 followed by evaporation of the water.
The other was reaction of the triazole with hydrochloric acid followed by evaporation. Then the hydrochloride was dissolved in ethanol, and a saturated solution of NaClO4 in ethanol was added at 55 C. NaCl precipitated and the mix was stirred at 55C for 10 minutes. The NaCl was filtered off, and the ethanol was evaporated.
The products from the two reactions are not identical. They are both very explosive and react about the same in the hammer and cook-off tests, but the ethanol preparation produces a material that is difficult to dry out, while the HClO4 method makes a non-hygroscopic material (but mine was contaminated with an excess of one of the reactants).
There is much work to be done.


[Edited on 22-12-2021 by Microtek]

MineMan - 26-12-2021 at 02:36

Quote: Originally posted by Microtek  
My experiments with urazine are on hold, since I have come to doubt the identity (or maybe purity) of the compound I had synthesized. It seems I will have to buy some after all.

In the mean time, I have been experimenting with some 4-amino-1,2,4-triazole that I ordered some years ago to test the capability of a supplier. I was searching for candidates for melt castable explosives, and wanted to try some aminotriazole compounds. I had some limited success with the picrate salt IIRC, but in the end I put it on indefinite hold.
However, the urazine salts inspired me to make some more tests. The nitrate and perchlorate salts are both energetic as would be expected, but the nitrate is not reliably initiated in my setup. It may possibly be of interest as a less sensitive explosive.
The perchlorate salt is much more sensitive, and seems to propagate detonation very effectively. My initial sensitivity tests involve a rapid cook-off test, a hammer test and a friction test. In the cook-off test, 50 mg ATrzP melts, bubbles and finally "pops" with enough force to make a large hole in the Al foil it is held on. It doesn't detonate though. ATrzN just burns with a hissing flame. In the hammer test 50 mg ATrzP is easily set off with moderate hammer blows, and detonates with a loud report and a VERY bright flash. The explosion is reminiscent of a drop of NG on tissue paper, in that it seems to be the entire mass of explosive that detonates (often, these tests will only set off parts of the explosive, and successive blows can achieve more detonations). ATrzN is only set off with difficulty in the hammer test. I wasn't able to initiate either of them by rubbing between hammer and anvil, but AtrzP gave a (very) positive reaction in my oblique impact test, which is a steel pendulum drop hammer which impacts a steel surface at a 25 degree angle from horizontal. The pendulum can be released from varying heights and the sample can be placed directly on the steel anvil or on a small piece of fine grit sand paper. In this test, ATrzP gave a positive test (any sign of chemical decomposition) at a slightly lower height than PETN, but did so more reliably. PETN often does not explode, but decomposition can be detected by smell. ATrzP usually explodes with flame and a clearly audible report.

I also tested performance in the manner that I described under the "NHN without hydrazine hydrate" thread. I didn't press it very much because of the insufficiently tested sensitivity, but at a density of only 1.55 g/cc, the dent in aluminum bar stock was on par with that of HMX at >1.8 g/cc. If I can tame the sensitivity of the material (inert binders, perchlorate/nitrate mixes or other methods) it could be an interesting avenue of research.

I experimented with two different methods of preparation: One was straight forward reaction of 4-amino-1,2,4-triazole with HClO4 followed by evaporation of the water.
The other was reaction of the triazole with hydrochloric acid followed by evaporation. Then the hydrochloride was dissolved in ethanol, and a saturated solution of NaClO4 in ethanol was added at 55 C. NaCl precipitated and the mix was stirred at 55C for 10 minutes. The NaCl was filtered off, and the ethanol was evaporated.
The products from the two reactions are not identical. They are both very explosive and react about the same in the hammer and cook-off tests, but the ethanol preparation produces a material that is difficult to dry out, while the HClO4 method makes a non-hygroscopic material (but mine was contaminated with an excess of one of the reactants).
There is much work to be done.


[Edited on 22-12-2021 by Microtek]


Is a dinitrate possible? Urazine has the benefit of oxygen balance.

Laboratory of Liptakov - 4-1-2022 at 15:34

I keep saying that. Perchlorates are an unexplored area. Many discoveries are yet to be made. In the sense of primary and primarily secondary choristans. For easy safely initiation.:cool:

Microtek - 10-1-2022 at 04:52

In my research into triazoles, I recently stumbled onto a class of coordination complexes known as EMOFs - energetic metal-organic frameworks.
In a number of very new papers, the authors are throwing around some quite extraordinary numbers:

Substances having measured sensitivities less than TNT coupled with calculated detonation energy of 3.9 kcal/g (that is not an error; about twice ONC or CL-20), Pcj of 50-60 GPa and VOD of 10-11 km/s. In addition, they have measured thermal stabilities of around 300C.

Of course, several of these numbers are calculated and it remains to be seen whether the models are any good at predicting performance at these extremes of the spectrum. Still, if they are reasonably close, it is a huge leap in performance, without any compromise with regards to safety.

Some of the most energetic EMOFs I have seen are based on coupled furazan-tetrazoles as ligands around metal ions. These form 1-,2- , or 3-D frameworks that can have other ions in the voids in the structure.

Some appetizers:

https://pubs.acs.org/doi/10.1021/acs.inorgchem.9b01636#

Almost 12 km/s

Very high densities



[Edited on 10-1-2022 by Microtek]

[Edited on 10-1-2022 by Microtek]

katyushaslab - 10-1-2022 at 15:16

For the second paper you linked, the starting material (4-Amino-1,2,5-oxadiazole-3-carbonitrile) seems to be the hardest part of the problem (to me).

Oxidation of the amino group to a nitro group might be doable with KMnO4 under basic conditions, then I think its a condensation under basic conditions? These two steps might even be doable in one pot. It reminds somewhat of the 5-aminotetrazole to the Sodium 5,5 nitrotetrazole procedure.

The remaining steps (forming the tetrazole rings with sodium azide, and then forming the complex) don't look terribly difficult.

Microtek - 10-1-2022 at 23:15

I found another paper (attached) that describes their improved synthesis of a number of key materials. They make 4-Amino-1,2,5-oxadiazole-3-carbonitrile in two steps from malononitrile. In many of the papers I have read on linked furazans, malononitrile seems to be the starting material...

Attachment: MULTI-CYCLIC OXADIAZOLES.pdf (1.4MB)
This file has been downloaded 220 times


MineMan - 13-1-2022 at 05:12

Quote: Originally posted by Microtek  
In my research into triazoles, I recently stumbled onto a class of coordination complexes known as EMOFs - energetic metal-organic frameworks.
In a number of very new papers, the authors are throwing around some quite extraordinary numbers:

Substances having measured sensitivities less than TNT coupled with calculated detonation energy of 3.9 kcal/g (that is not an error; about twice ONC or CL-20), Pcj of 50-60 GPa and VOD of 10-11 km/s. In addition, they have measured thermal stabilities of around 300C.

Of course, several of these numbers are calculated and it remains to be seen whether the models are any good at predicting performance at these extremes of the spectrum. Still, if they are reasonably close, it is a huge leap in performance, without any compromise with regards to safety.

Some of the most energetic EMOFs I have seen are based on coupled furazan-tetrazoles as ligands around metal ions. These form 1-,2- , or 3-D frameworks that can have other ions in the voids in the structure.

Some appetizers:

https://pubs.acs.org/doi/10.1021/acs.inorgchem.9b01636#

Almost 12 km/s

Very high densities



[Edited on 10-1-2022 by Microtek]

[Edited on 10-1-2022 by Microtek]


Have any of these been actually made and tested? Are these doable for you to synth?

Microtek - 16-1-2022 at 03:40

Most of these have been synthesized and tested with respect to density, heat of formation, stability and sensitivity. Most of the energetic properties are computed via semi-empirical methods such as the Kamlet-Jacobs equations. That is why I say that it remains to be seen whether these equations work for this kind of material.

I believe that I can relatively easily prepare the material called ATRZ-1 ([Cu(4,4'-azo-1,2,4-triazole)3(NO3)2]n). It is basically made by mixing boiling aqueous solutions of Cu(NO3)2 and 4,4'-azo-1,2,4-triazole, filtering and allowing the filtrate to slowly evaporate until crystals form. The ligand 4,4'-azo-1,2,4-triazole is prepared by oxidative azo-coupling of 4-amino-1,2,4-triazole using sodium dichloroisocyanurate (pool chemical). As mentioned previously, I possess 4-amino-1,2,4-triazole from an old experiment, and I have prepared 4,4'-azo-1,2,4-triazole (I hope). I will attempt the synthesis of ATRZ-1, and also see what happens if Cu(ClO4)2 is substituted for the nitrate.

ATRZ-1 has a heat of detonation of more than 15 kJ/g, but a density of only 1.68 g/cc, so the performance is predicted to be only about the level of HMX, but a perchlorate analogue might be better.


On another note, I received my carbohydrazide recently, and have prepared urazine following the procedure from Inorganic Synthesis vol 4. It involves adding concentrated HCl and then slowly heating to 220C. Then water is added to dissolve the byproduct hydrazine*HCl, and the insoluble urazine is filtered off. The yield exactly matched the litterature procedure. I then added a slight excess of sulfuric acid to the recovered filtrate, which caused a large amount of white crystals to precipitate. This should be hydrazine sulfate, and after filtering, washing with cold water and drying, I recovered a yield of about 70%. In total, 23.4 g carbohydrazide was converted to 11.5 g urazine and 15.6 g hydrazine sulfate.
The 1.16 g urazine was then reacted with one molar equivalent of 50% HClO4, and stirred for 1 hour at room temp, then 1 hour at 50C. Then the water was evaporated by placing the entire mass in a petri dish and heating to 60C on the hotplate. The product UZP is very dense and extremely energetic (in the hammer test), but moderately hygroscopic. I tried desensitizing it by dissolving 5 parts by weight of bees wax in a minimal amount of detergent gasoline, mixing this with 95 parts of the UZP and evaporating the gasoline while continually agitating the mix. The sensitivity is indeed reduced a little, but the wax does nothing for the hygroscopicity. The powder was pressed into a 7mm ID brass tube and easily achieved a packing density of 2.05 g/cc, however, when this was tested in my usual setup, a very disappointing result of 2.92 mm dent depth in 20 mm Al bar stock was achieved.
For comparison:

Picric acid: 3.53 mm
5-ATz*NO3: 3.84 mm
RDX: 4.13 mm
HMX: 4.35 mm

It was only at this point I discovered the hygroscopicity issue. I had left weighing boats with both some of the neat crystals and also some of the wax treated powder in my workshop for testing. The relative humidity is slightly higher in my workshop than in my lab, and the samples that were in my lab *looked* fine, but the ones in the workshop had visibly absorbed atmospheric moisture. It may certainly be possible to work around both the sensitivity issue and the hygroscopicity (the right PBX formulation may solve both), but before working on that, I will conduct further tests to see if better performance can't be achieved from the dry product.

Laboratory of Liptakov - 16-1-2022 at 09:19

You use plate dent test with aluminium brick I estimate. Density 2.05 seems good. ID 7mm OK. But weight of output segment? 300mg? 500mg?
Maybe I missed it. But I don't see the weight of the output segment in the text.

MineMan - 16-1-2022 at 20:11

Quote: Originally posted by Microtek  
Most of these have been synthesized and tested with respect to density, heat of formation, stability and sensitivity. Most of the energetic properties are computed via semi-empirical methods such as the Kamlet-Jacobs equations. That is why I say that it remains to be seen whether these equations work for this kind of material.

I believe that I can relatively easily prepare the material called ATRZ-1 ([Cu(4,4'-azo-1,2,4-triazole)3(NO3)2]n). It is basically made by mixing boiling aqueous solutions of Cu(NO3)2 and 4,4'-azo-1,2,4-triazole, filtering and allowing the filtrate to slowly evaporate until crystals form. The ligand 4,4'-azo-1,2,4-triazole is prepared by oxidative azo-coupling of 4-amino-1,2,4-triazole using sodium dichloroisocyanurate (pool chemical). As mentioned previously, I possess 4-amino-1,2,4-triazole from an old experiment, and I have prepared 4,4'-azo-1,2,4-triazole (I hope). I will attempt the synthesis of ATRZ-1, and also see what happens if Cu(ClO4)2 is substituted for the nitrate.

ATRZ-1 has a heat of detonation of more than 15 kJ/g, but a density of only 1.68 g/cc, so the performance is predicted to be only about the level of HMX, but a perchlorate analogue might be better.


On another note, I received my carbohydrazide recently, and have prepared urazine following the procedure from Inorganic Synthesis vol 4. It involves adding concentrated HCl and then slowly heating to 220C. Then water is added to dissolve the byproduct hydrazine*HCl, and the insoluble urazine is filtered off. The yield exactly matched the litterature procedure. I then added a slight excess of sulfuric acid to the recovered filtrate, which caused a large amount of white crystals to precipitate. This should be hydrazine sulfate, and after filtering, washing with cold water and drying, I recovered a yield of about 70%. In total, 23.4 g carbohydrazide was converted to 11.5 g urazine and 15.6 g hydrazine sulfate.
The 1.16 g urazine was then reacted with one molar equivalent of 50% HClO4, and stirred for 1 hour at room temp, then 1 hour at 50C. Then the water was evaporated by placing the entire mass in a petri dish and heating to 60C on the hotplate. The product UZP is very dense and extremely energetic (in the hammer test), but moderately hygroscopic. I tried desensitizing it by dissolving 5 parts by weight of bees wax in a minimal amount of detergent gasoline, mixing this with 95 parts of the UZP and evaporating the gasoline while continually agitating the mix. The sensitivity is indeed reduced a little, but the wax does nothing for the hygroscopicity. The powder was pressed into a 7mm ID brass tube and easily achieved a packing density of 2.05 g/cc, however, when this was tested in my usual setup, a very disappointing result of 2.92 mm dent depth in 20 mm Al bar stock was achieved.
For comparison:

Picric acid: 3.53 mm
5-ATz*NO3: 3.84 mm
RDX: 4.13 mm
HMX: 4.35 mm

It was only at this point I discovered the hygroscopicity issue. I had left weighing boats with both some of the neat crystals and also some of the wax treated powder in my workshop for testing. The relative humidity is slightly higher in my workshop than in my lab, and the samples that were in my lab *looked* fine, but the ones in the workshop had visibly absorbed atmospheric moisture. It may certainly be possible to work around both the sensitivity issue and the hygroscopicity (the right PBX formulation may solve both), but before working on that, I will conduct further tests to see if better performance can't be achieved from the dry product.


Please! This is a project I am greatly interested in! How sensitive was this? I assume similar to SADS or so? Amazing that water desensitizes it so much. Perhaps the nitrate analog might be almost as interesting? I am after performance at any cost… and this seems like the king other than the EMOFs. If that synth works out maybe we can find a way to synth the ones at 2-3g/cc. They hold more promise than Urazine but the difficult synthesis seems depressing.

MineMan - 16-1-2022 at 20:12

Quote: Originally posted by Microtek  
Most of these have been synthesized and tested with respect to density, heat of formation, stability and sensitivity. Most of the energetic properties are computed via semi-empirical methods such as the Kamlet-Jacobs equations. That is why I say that it remains to be seen whether these equations work for this kind of material.

I believe that I can relatively easily prepare the material called ATRZ-1 ([Cu(4,4'-azo-1,2,4-triazole)3(NO3)2]n). It is basically made by mixing boiling aqueous solutions of Cu(NO3)2 and 4,4'-azo-1,2,4-triazole, filtering and allowing the filtrate to slowly evaporate until crystals form. The ligand 4,4'-azo-1,2,4-triazole is prepared by oxidative azo-coupling of 4-amino-1,2,4-triazole using sodium dichloroisocyanurate (pool chemical). As mentioned previously, I possess 4-amino-1,2,4-triazole from an old experiment, and I have prepared 4,4'-azo-1,2,4-triazole (I hope). I will attempt the synthesis of ATRZ-1, and also see what happens if Cu(ClO4)2 is substituted for the nitrate.

ATRZ-1 has a heat of detonation of more than 15 kJ/g, but a density of only 1.68 g/cc, so the performance is predicted to be only about the level of HMX, but a perchlorate analogue might be better.


On another note, I received my carbohydrazide recently, and have prepared urazine following the procedure from Inorganic Synthesis vol 4. It involves adding concentrated HCl and then slowly heating to 220C. Then water is added to dissolve the byproduct hydrazine*HCl, and the insoluble urazine is filtered off. The yield exactly matched the litterature procedure. I then added a slight excess of sulfuric acid to the recovered filtrate, which caused a large amount of white crystals to precipitate. This should be hydrazine sulfate, and after filtering, washing with cold water and drying, I recovered a yield of about 70%. In total, 23.4 g carbohydrazide was converted to 11.5 g urazine and 15.6 g hydrazine sulfate.
The 1.16 g urazine was then reacted with one molar equivalent of 50% HClO4, and stirred for 1 hour at room temp, then 1 hour at 50C. Then the water was evaporated by placing the entire mass in a petri dish and heating to 60C on the hotplate. The product UZP is very dense and extremely energetic (in the hammer test), but moderately hygroscopic. I tried desensitizing it by dissolving 5 parts by weight of bees wax in a minimal amount of detergent gasoline, mixing this with 95 parts of the UZP and evaporating the gasoline while continually agitating the mix. The sensitivity is indeed reduced a little, but the wax does nothing for the hygroscopicity. The powder was pressed into a 7mm ID brass tube and easily achieved a packing density of 2.05 g/cc, however, when this was tested in my usual setup, a very disappointing result of 2.92 mm dent depth in 20 mm Al bar stock was achieved.
For comparison:

Picric acid: 3.53 mm
5-ATz*NO3: 3.84 mm
RDX: 4.13 mm
HMX: 4.35 mm

It was only at this point I discovered the hygroscopicity issue. I had left weighing boats with both some of the neat crystals and also some of the wax treated powder in my workshop for testing. The relative humidity is slightly higher in my workshop than in my lab, and the samples that were in my lab *looked* fine, but the ones in the workshop had visibly absorbed atmospheric moisture. It may certainly be possible to work around both the sensitivity issue and the hygroscopicity (the right PBX formulation may solve both), but before working on that, I will conduct further tests to see if better performance can't be achieved from the dry product.


Dornier could compute one or two of these to verify. His EOS is quite different

Microtek - 17-1-2022 at 00:12

LL: My standard test setup is as follows:

A 3D-printed holder is glued to the 20mm thick aluminum bar stock. Then the brass tube (7mm ID, 8mm OD, 40mm length, and the end is cut on my lathe to ensure that it is completely perpendicular to the axis of the tube) is inserted and glued into the holder.
The brass tube contains 1.000 +- 0.002 g of the substance to be tested and 0.300 +- 0.002 g PETN. It is initiated by aminoguanidinium nickel perchlorate.



MineMan
UZP is quite sensitive when dry, about on the level of ETN. With wax desensitization, maybe on par with PETN.
I just did another test with a fresh batch of UZP. Thia time I stored the powder in a dessicator, then prepared a PBX consisting of 6 parts PIB/5w40 oil (both dissolved in detergent gasoline) and 94 parts UZP. After mixing the components, most of the gasoline was evaporated, and the almost dry composite was placed in the dessicator overnight. Then it was pressed into the brass tube at a quite moderate pressure, to eliminate potential dead pressing as an issue. The density of the charge was still right around 2.00 g/cc, and the assembled charge was placed back into the dessicator until just before firing.
Despite all this, the result was only 2.934 mm dent depth. I therefore conclude that either it is impractical to keep the material dry enough, or else the problem lies elsewhere. Perhaps UZP loses more performance at this scale than some other energetics like RDX and HMX, or perhaps the model simply overestimates the performance of this material. Perhaps it is very easily dead pressed.

IMG_20220117_082640 (2).jpg - 1.7MB

Laboratory of Liptakov - 17-1-2022 at 00:20

Great measurement, hat off. I finally see someone doing accurate tests. Thanks.....:cool:
And not like some who wrote "I heard it exploded", sure it works...:D

[Edited on 17-1-2022 by Laboratory of Liptakov]

MineMan - 17-1-2022 at 16:35

Quote: Originally posted by Microtek  
LL: My standard test setup is as follows:

A 3D-printed holder is glued to the 20mm thick aluminum bar stock. Then the brass tube (7mm ID, 8mm OD, 40mm length, and the end is cut on my lathe to ensure that it is completely perpendicular to the axis of the tube) is inserted and glued into the holder.
The brass tube contains 1.000 +- 0.002 g of the substance to be tested and 0.300 +- 0.002 g PETN. It is initiated by aminoguanidinium nickel perchlorate.



MineMan
UZP is quite sensitive when dry, about on the level of ETN. With wax desensitization, maybe on par with PETN.
I just did another test with a fresh batch of UZP. Thia time I stored the powder in a dessicator, then prepared a PBX consisting of 6 parts PIB/5w40 oil (both dissolved in detergent gasoline) and 94 parts UZP. After mixing the components, most of the gasoline was evaporated, and the almost dry composite was placed in the dessicator overnight. Then it was pressed into the brass tube at a quite moderate pressure, to eliminate potential dead pressing as an issue. The density of the charge was still right around 2.00 g/cc, and the assembled charge was placed back into the dessicator until just before firing.
Despite all this, the result was only 2.934 mm dent depth. I therefore conclude that either it is impractical to keep the material dry enough, or else the problem lies elsewhere. Perhaps UZP loses more performance at this scale than some other energetics like RDX and HMX, or perhaps the model simply overestimates the performance of this material. Perhaps it is very easily dead pressed.


Excellent work! Have you given up with this material or would you be willing to do a test at 1.9 density to avoid deadpressing? I admit the results seem disappointing. But we do know, at the very least it should be at least as powerful as RDX. You noticed that the hammer test was extremely energetic. Is it possible to seal the crystals from moisture during recrystallization with an additive?

Can you try making a mix of 50 percent PETN and 50 percent Urazine? Then we could access forsure, if this is weaker or stronger than PETN. I have a feeling it’s not a full det. No compound at that density would produce such a small dent

What size were your crystals? The paper reported .5-1mm

Microtek - 17-1-2022 at 23:35

No, I haven't given completely up on it, and I do have some left of my first batch of urazine. I was thinking that I would see if the nitrate is useful, and I could also try a PETN mix and maybe a very lightly pressed charge. I tried making the picrate, but adding urazine to molten picric acid did not produce anything other than the starting materials.
My UZP crystals were smaller than the ones reported in the paper, but still relatively large. They are not uniform and they don't crystallize cleanly. Since the material is produced by heating the mix of HClO4 and urazine, I agitate it regularly to avoid a solid lump of highly sensitive and energetic HE that I then need to break down mechanically. When I triturate the crystals under detergent gasoline, they are easily reduced in size without applying too much force.
I would like to try a charge without any additives, but am leery of pressing such a sensitive HE (especially as the crystals "creak" as they are pressed, somewhat like snow when it is compacted).

On another note, I did some more experiments with 4-amino-1,2,4-triazolium perchlorate. I prepared some from equimolar (10 mmol) amounts of perchloric acid and the parent triazole. Then I evaporated the water by heating in a petri dish on a hotplate. I let it coodown with agitation and then placed it in a dessicator. After sitting ca. 24 hours, I ground it in a motar and pestle, about 30 mg at a time. Then I placed it in the dessicator again. 1.000 g of the, now much finer, powder was pressed uneventfully to 1.75 g/cc which corresponds to more than 96 % TMD according to a paper that I found (attached).
On detonation, the dent produced was 4.38 mm deep, which is on par with HMX (4.35 mm). In the paper, they find a sensitivity of 30 kg*cm (HMX 34 kg*cm), but in my own tests, my impression is that it is more sensitive than that (perhaps it is more sensitive to friction which plays a part in most non-ideal impacts).
Anyway, I also discovered that it melts below 100C. In the paper they say 84C, my own melting point determination says 78C at 12 degrees per minute, but this may be due to included water. When I let the temp continue to rise, no visible sign of decomposition could be detected up to 225C. This long molten temperature range makes it a candidate for melt casting, possibly in conjunction with other materials such as the nitrate or maybe urazine perchlorate. I would still like to lower the sensitivity a little, though.

[Edited on 18-1-2022 by Microtek]

[Edited on 18-1-2022 by Microtek]

Attachment: phpZEHUYt (114kB)
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Dornier 335A - 18-1-2022 at 11:03

Quote: Originally posted by Microtek  
In my research into triazoles, I recently stumbled onto a class of coordination complexes known as EMOFs - energetic metal-organic frameworks.
In a number of very new papers, the authors are throwing around some quite extraordinary numbers:

Substances having measured sensitivities less than TNT coupled with calculated detonation energy of 3.9 kcal/g (that is not an error; about twice ONC or CL-20), Pcj of 50-60 GPa and VOD of 10-11 km/s. In addition, they have measured thermal stabilities of around 300C.

Of course, several of these numbers are calculated and it remains to be seen whether the models are any good at predicting performance at these extremes of the spectrum. Still, if they are reasonably close, it is a huge leap in performance, without any compromise with regards to safety.

Some of the most energetic EMOFs I have seen are based on coupled furazan-tetrazoles as ligands around metal ions. These form 1-,2- , or 3-D frameworks that can have other ions in the voids in the structure.

Some appetizers:

https://pubs.acs.org/doi/10.1021/acs.inorgchem.9b01636#

Almost 12 km/s

Very high densities



[Edited on 10-1-2022 by Microtek]

[Edited on 10-1-2022 by Microtek]


Those incredible claims caught my eye and I skimmed through the three articles you linked.

First off, 3.9 kcal/g or 16 kJ/g is obviously an error or simply clickbait. A hypothetical "ultimate" explosive in the form of (N-N-)n decomposing into n N2 would have a detonation energy of about 22 kJ/g, and another in the form of monatomic oxygen and carbon would have ~20 kJ/g. Anything with reasonable bonds would not come close to 16 kJ/g. ONC and DFF reach about 8 kJ/g and simple tetrazoles around 6 kJ/g. Adding heavy and inert metal atoms will obviously not improve this figure.

In the first article, the authors compare the detonation energy of Cu-btm-NH3OH with RDX and HMX but they botched it completely: their energy is wrong for the reaction they assume (ammonia as product), and the reaction they assume is wrong. They claim 6.1 kJ/g but the real value is 1.9 g/kJ. They also brag about their high heat of combustion but that is just a way to say that the oxygen balance is poor...

The second article presents the compound Ag16C54H8N110O27, that is 40% silver by weight, with an oxygen balance of -31%. The enthalpy of formation is a mediocre 2.3 kJ/g and the density is very low at only 2 g/cm3 for something with so much silver! Claiming that this should reach nearly 12 km/s is absolutely bonkers. My best guess is 5-6 km/s with a detonation energy of 3 kJ/g. The problem lies in their choice of method. They use the empirical Kamlet-Jacobs, which was made for CHNO-compounds.

Both article 2 and 3 reference the same paper that applied Kamlet-Jacobs to high nitrogen metal salts and compared the results to EXPLO5 calculations. The accuracy is acceptable for light metals (less than 1 km/s overestimation) but they don't even evaluate heavy atoms like silver and lead. Lead azide calculated with an empirical method gives 10.6 km/s and 52 GPa compared to the real 5.2 km/s.

The third article lists a number of EMOFs with high densities and ridiculous detonation performances. Kamlet-Jacobs is once again the problem. The density increase from added heavy atoms does not improve performance in reality. Lead azide (5.2 km/s) is not better than hydrazoic acid (7.6 km/s) despite its four times higher density for example. The same applies to tetrazoles and their metal salts and complexes: the salts improve properties like stability, hygroscopicity etc but not performance.

All papers about EMOFs I can find seem to come from the same Chinese universities, contain the same overestimated detonation performance, and use the same invalid methods for calculation.

MineMan - 18-1-2022 at 11:06

Quote: Originally posted by Microtek  
No, I haven't given completely up on it, and I do have some left of my first batch of urazine. I was thinking that I would see if the nitrate is useful, and I could also try a PETN mix and maybe a very lightly pressed charge. I tried making the picrate, but adding urazine to molten picric acid did not produce anything other than the starting materials.
My UZP crystals were smaller than the ones reported in the paper, but still relatively large. They are not uniform and they don't crystallize cleanly. Since the material is produced by heating the mix of HClO4 and urazine, I agitate it regularly to avoid a solid lump of highly sensitive and energetic HE that I then need to break down mechanically. When I triturate the crystals under detergent gasoline, they are easily reduced in size without applying too much force.
I would like to try a charge without any additives, but am leery of pressing such a sensitive HE (especially as the crystals "creak" as they are pressed, somewhat like snow when it is compacted).

On another note, I did some more experiments with 4-amino-1,2,4-triazolium perchlorate. I prepared some from equimolar (10 mmol) amounts of perchloric acid and the parent triazole. Then I evaporated the water by heating in a petri dish on a hotplate. I let it coodown with agitation and then placed it in a dessicator. After sitting ca. 24 hours, I ground it in a motar and pestle, about 30 mg at a time. Then I placed it in the dessicator again. 1.000 g of the, now much finer, powder was pressed uneventfully to 1.75 g/cc which corresponds to more than 96 % TMD according to a paper that I found (attached).
On detonation, the dent produced was 4.38 mm deep, which is on par with HMX (4.35 mm). In the paper, they find a sensitivity of 30 kg*cm (HMX 34 kg*cm), but in my own tests, my impression is that it is more sensitive than that (perhaps it is more sensitive to friction which plays a part in most non-ideal impacts).
Anyway, I also discovered that it melts below 100C. In the paper they say 84C, my own melting point determination says 78C at 12 degrees per minute, but this may be due to included water. When I let the temp continue to rise, no visible sign of decomposition could be detected up to 225C. This long molten temperature range makes it a candidate for melt casting, possibly in conjunction with other materials such as the nitrate or maybe urazine perchlorate. I would still like to lower the sensitivity a little, though.

[Edited on 18-1-2022 by Microtek]

[Edited on 18-1-2022 by Microtek]


Excellent work! Is that the compound that has twice the energy of a regular explosive? Considering it made the same dent as HMX, but at a lower density, and melt cast! Impressive :). Are there any denser more powerful ones you can do… well if you decide to after reading dorniers post

Microtek - 18-1-2022 at 23:13

Oh, I tend to agree with Dornier. I also noted the inconsistencies and strange mish-mash of models, the fixation on cumbustion energies. Gasoline also has a great combustion energy (ca. 40 kJ/g), but is not explosive. I also have a hard time seeing where the extra energy would be coming from with these coordination complexes. However, it only costs me a little work, and a little bit of chemicals that I've got on hand anyway to test some of them out to know for sure. Sometimes phenomena are observed that doesn't fit with the current understanding. Then, if they are repeatable, that understanding must be revised. For this reason, the experiment is king, and any theoretical prediction is just a (more or less) educated guess.

Just to clarify, the explosive I was describing in my last post is not one of these exotic EMOFs, it is simply the perchlorate salt of 4-amino-triazole.

MineMan - 19-1-2022 at 02:59

Ahh!

Well still impressive for the density. Any luck on the Urazine nitrate or perchlorate

Microtek - 1-2-2022 at 22:57

I have tried preparing urazine nitrate, but it seems that the combination of volatility and lower acidity of nitric acid means that mostly (only?) unreacted urazine is recovered.
I did prepare a 1:1 molar mix of urazine perchlorate and 4-amino-1,2,4-triazole perchlorate by mixing 5 mmol of urazine and 4-ATrz, adding 10 mmol HClO4 (50%) and evaporating water at 60C. The mix is not quite as powerful as ATrz-perchlorate alone, but more so than a 1:1 mix with PETN. This might indicate that urazine perchlorate does have some potential, that simply isn't realized under the conditions I have been using. Maybe it requires more powerful initiation despite being quite sensitive, to perform maximally (like NG which can detonate at different rates depending on initiation and containment).

MineMan - 2-2-2022 at 21:56

Hmm. Dinitrogen pentaoxide maybe needed?

Do you plan to keep working with the UP… I feel your the only one that can. It’s not overly sensitive so it has great potential.

Microtek - 3-2-2022 at 23:38

N2O5 won't help matters. We don't need the nitronium ion, and the problem is that urazine is so weakly basic that it can't hold on to the nitrate ion. It doesn't stay protonated, especially since nitric acid is relatively volatile which pushes the UZ*HNO3 <--> UZ + HNO3 equilibrium towards the right as it evaporates. The same behavior is seen with aminonitroguanidinium nitrate, but to a lesser degree (so it takes longer for ANQN to lose all the nitrate).

I'm going to try to measure VOD with an oscilloscope, but it is an experimental procedure I haven't tried before (I don't know much about electronics - I only barely know how to operate an oscilloscope), but I've found some papers that describe different methods.

The simplest method uses ionization probes, which can be made from coaxial cables. It is based on using the conductivity of the reaction zone just behind the detonation front to act as a switch to close an electrical circuit. This can then be detected with an oscilloscope.
Another option that looks attractive is based on detecting the arrival of the detonation front based on capturing the emitted light, and guiding it to fast photodiodes using fiberoptic cable. The optical detectors they used in the paper were quite expensive (ca. 500 dollars a piece and I need at least two - more preferably a few more), but I've found some much more affordable ones that I'm hoping are good enough.

Laboratory of Liptakov - 4-2-2022 at 00:56

In my opinion, the detonation pressure is more important than the detonation velocity VoD. For this reason, the dent plate method is the most convincing. It's cheap, fast and shows the most important things. That is, the mechanical effect on the pad. The speed of light is the highest of all. But it moves the spacecraft only slightly. Therefore, is best aluminum brick and 1 gram EM. In a column of material that is taller than wider. The so-called supra-square. In a cavity of 7 mm, for example 15 mm, in a cavity of 8 mm, for example 12 mm. The crater from ETN (or PETN) then serves as a reference depth. VoD measurement (electrically or optically) has a very laborious preparation, much more grams is used. And the test is loud. Not to mention the price of the measuring device. In amateur conditions is it luxury. // Let's make things as simple as is possible. But not simplier // Albert Einstein......:cool:

MineMan - 4-2-2022 at 13:44

Quote: Originally posted by Microtek  
N2O5 won't help matters. We don't need the nitronium ion, and the problem is that urazine is so weakly basic that it can't hold on to the nitrate ion. It doesn't stay protonated, especially since nitric acid is relatively volatile which pushes the UZ*HNO3 <--> UZ + HNO3 equilibrium towards the right as it evaporates. The same behavior is seen with aminonitroguanidinium nitrate, but to a lesser degree (so it takes longer for ANQN to lose all the nitrate).

I'm going to try to measure VOD with an oscilloscope, but it is an experimental procedure I haven't tried before (I don't know much about electronics - I only barely know how to operate an oscilloscope), but I've found some papers that describe different methods.

The simplest method uses ionization probes, which can be made from coaxial cables. It is based on using the conductivity of the reaction zone just behind the detonation front to act as a switch to close an electrical circuit. This can then be detected with an oscilloscope.
Another option that looks attractive is based on detecting the arrival of the detonation front based on capturing the emitted light, and guiding it to fast photodiodes using fiberoptic cable. The optical detectors they used in the paper were quite expensive (ca. 500 dollars a piece and I need at least two - more preferably a few more), but I've found some much more affordable ones that I'm hoping are good enough.


Microtek! Could lithium work as a good ligand for AQ? For example lithium aminoguanidine diperchlorate? If so, the synthesis should be that of the copper variant but with lithium instead? Perhaps the lithium could help make these weakly basic molecules more stable? Both nickel and Copper AQ diperchlorate so remarkable stability outside of water, and no issues with humidity… perhaps the Urazine could be stabilized this way as well… by adding a metal ligand. Lithium is the most preferable?

LL is right. Detonation pressure only matters.

Microtek - 5-2-2022 at 01:01

Lithium (or another metal ion) would be the coordination center, and AQ would be the ligand. This kind of complex is what I use for my primary, though using nickel instead of lithium. I don't think alkali metals make for very good coordination centers, but coordination chemistry isn't my specialty.
Generally, metal ions do not contribute to the explosive performance (as Dornier pointed out earlier, it's like mixing your wood with ashes before lighting the fire), but can benefit other parameters such as stability, DDT ability, etc.
It might be possible to make a complex with urazine as a ligand and perchlorate anions around a (transition) metal center. It could then be hoped that this would make it less sensitive, but more willing to go high order. Then it would be nice if the performance didn't drop too much because of the metal content.

With regards to my planned VOD measurement, take a look at the paper I'm attaching. They use probe spacings of 1-4mm on a (strongly confined) charge with rectangular cross section and a width of 0.5 mm. They get measurements with a standard deviation of 13 - 60 m/s, corresponding to an error on the order of 0.5%. So charge size is not an issue.
It is true that detonation pressure is very important, but there is a very strong correlation between VOD and Pcj, so measuring VOD will give a very good estimate of Pcj. Additionally, by using several probes, the acceleration of the detonation front could be mapped and this would make it possible to model things like critical diameter and non-ideal behaviour.
In the attached paper, they use an oscilloscope with 500MHz bandwidth and 2.5 GSa/s, and that kind of specification costs upwards of 10000 dollars, but if you drop to 200 MHz and 1 GSa/s you can get a very decent one (I'm told) for about 400 dollars. Since 200 MHz should be enough to record 200 oscillations in the time it takes the detonation front to move 10 mm (at 10 km/s), I'm betting on this being sufficient time resolution.


Attachment: Application and Analysis of Discrete Fiber Probes in Determining Detonation Velocity of Microcharges.pdf (3.2MB)
This file has been downloaded 197 times


MineMan - 5-2-2022 at 10:15

Quote: Originally posted by Microtek  
Lithium (or another metal ion) would be the coordination center, and AQ would be the ligand. This kind of complex is what I use for my primary, though using nickel instead of lithium. I don't think alkali metals make for very good coordination centers, but coordination chemistry isn't my specialty.
Generally, metal ions do not contribute to the explosive performance (as Dornier pointed out earlier, it's like mixing your wood with ashes before lighting the fire), but can benefit other parameters such as stability, DDT ability, etc.
It might be possible to make a complex with urazine as a ligand and perchlorate anions around a (transition) metal center. It could then be hoped that this would make it less sensitive, but more willing to go high order. Then it would be nice if the performance didn't drop too much because of the metal content.

With regards to my planned VOD measurement, take a look at the paper I'm attaching. They use probe spacings of 1-4mm on a (strongly confined) charge with rectangular cross section and a width of 0.5 mm. They get measurements with a standard deviation of 13 - 60 m/s, corresponding to an error on the order of 0.5%. So charge size is not an issue.
It is true that detonation pressure is very important, but there is a very strong correlation between VOD and Pcj, so measuring VOD will give a very good estimate of Pcj. Additionally, by using several probes, the acceleration of the detonation front could be mapped and this would make it possible to model things like critical diameter and non-ideal behaviour.
In the attached paper, they use an oscilloscope with 500MHz bandwidth and 2.5 GSa/s, and that kind of specification costs upwards of 10000 dollars, but if you drop to 200 MHz and 1 GSa/s you can get a very decent one (I'm told) for about 400 dollars. Since 200 MHz should be enough to record 200 oscillations in the time it takes the detonation front to move 10 mm (at 10 km/s), I'm betting on this being sufficient time resolution.


Your method makes perfect sense after that explanation.

As regards to lithium, it seems it works the best for LLs formula, which was once replaced by copper. Maybe lithium is overlooked? Unfortunately I don’t understand the chemistry and might be missing something. But if it works to bind the hexamine and perchlorate, why not a better ligand such as AQ, carbohydrazide, Urazine… and others I am sure. Lithium holds the record for VOd… lithium pentazolate.

Laboratory of Liptakov - 5-2-2022 at 13:02

The attached link explains everything. In the last century, a distance between sensors of 10 cm was used. There were no such fast devices for measurement....:cool:

Measuring VOD

pdb - 9-2-2022 at 13:27

Synchronising measuring instruments such as oscilloscopes with such fast phenomena is not easy. Here is an example:

During my engineering studies, I did an internship in an explosives research centre, where I worked on measuring the particle velocity behind the wavefront, which is of course lower than the VOD, but is nevertheless expressed in km/s. I used the magnetodynamic method, which consists of measuring the current induced in a metal strip immersed in a magnetic field and entrained by the products of the detonation. The explosive was 200 ml Astrolite A. Both oscilloscopes were triggered by a probe located a few centimetres upstream of the metal tape, but only one worked, and gave a null image. Either it was triggered too early or too late, or its calibration was not good. And I didn't get a second chance...



2.Measurement part.jpg - 154kB 1.Metal strip mounted on plexiglass.jpg - 143kB 0.Command console.jpg - 155kB 3.Device rear.jpg - 186kB 4.Device front.jpg - 189kB 5.Bunker (TNT 5 tons equivalent).jpg - 146kB 6.Before.jpg - 187kB 7.After.jpg - 179kB 8.Scope recording.jpg - 284kB 9.Aftermath.jpg - 175kB

[Edited on 9-2-22 by pdb]

Microtek - 10-2-2022 at 01:45

Yes, noise and unreliable triggering is why I was thinking that fiberoptics and a fast photodiode might be better. Time will tell. Whether I can get it to work or not, I'm sure I can find some use for my new oscilloscope.

Microtek - 10-2-2022 at 06:03

Acting on a suggestion from MineMan, I tested a mix of 85% UZP and 15% Al-powder (nominally 3 um). In my standard setup it gave a dent of 3.71 mm (picric acid 3.53 mm and RDX 4.13 mm). This is still considerably lower than would be expected from the calculated VOD and Pcj data, but much better than my previous test with pure UZP which gave 2.92 mm.

Laboratory of Liptakov - 10-2-2022 at 13:29

It are very good results. Powerful than picric acid. Aluminium usually decrease brisancion, but here is it conversely. And the UZP works in your cavity as primary - secondary ?....:cool:...... Was tested? I know, you use for start aminoguanidine some perchlorate + PETN 300 mg for maximal kick of examined compoud. 300 mg PETN is too much. This can affect the result. It's a huge blow to the test substance. It would make a small dent in aluminum, even if the place of the substance under investigation was pressed sand. Just my opinion, nothing more.

[Edited on 10-2-2022 by Laboratory of Liptakov]

Microtek - 10-2-2022 at 23:39

I think there is a very high likelihood of it being able to DDT reliably under strong confinement. When heated in folded Al-foil, it tends to "pop" like flash powder. It is not extremely flame sensitive, but I think it is likely that transition metal complexes might be.

Regarding the use of 300 mg PETN, you are correct that it is enough to slightly dent the Al block even if the base charge is completely inert. However, since I have plans to also test some things that are very insensitive, and since the experimental setup should be identical in order to compare the results, I settled on this amount of booster. The point in being careful to use the exact same amount of PETN every time, is to make sure that it adds the same amount to the dent in all experiments.

Laboratory of Liptakov - 11-2-2022 at 03:26

Yes, that makes sense. Promising materials that could be capable of DDT as a stand-alone monopropelant can be tested later.

MineMan - 11-2-2022 at 14:50

Microtek and LL. Yes it should DDT in strong cavity. That’s has been a thought I have had, although where we want it to shine is the detonation pressure. From this set up I would have expected a dent of over 4.5mm. Since the Al helped significantly I think this proves your original theory microtek. Despise the sensitivity it behaves as a non ideal explosive. Unless somehow the detonation wave is dead pressing the UZP ahead of it. But, the wave should move far faster then the speed of sound in UZP obviously.

I suppose the only other thing to try is compressing it to a density of 1.85-1.9 instead of over 2 or try larger quantity such as 5-10 grams. What do you think (LL and microtek)

Microtek - 12-2-2022 at 00:36

The last couple of tests I have done with UZP (with and without Al) have been just hand pressed precisely to avoid the likelyhood of dead pressing, so I'm afraid there's not much to gain there. However, another thing is that since UZP is so dense, 1 gram of it in a 7mm coloumn is just 13mm long (at 2 g/cc). It may be that the detonation doesn't have time to accelerate to its max velocity in such a short run. After all, when making shaped charges we make sure to have a certain head height above the apex of the cone. So, I will have to do an experiment with a longer charge. Then I will also have to do identical experiments with some of the other energetics, to establish a new baseline. To do these, I will have to construct a larger test chamber (since a longer charge with same diameter will obviously involve more material).

Laboratory of Liptakov - 12-2-2022 at 01:36

Of course, that bigger amount will give more exact results and exact measurement of density. I estimate that 5g will enough. Diameter of high pressed EM of cylinder should by in this cause 12 - 15 mm at 5 g.
However alu brick must be a lot bigger. Which can be expensive. For 5g I reccomend using lead block of diameter 70 mm and 60 mm high.
Which is possible use repeatedly after casting. And measurement can be on 0,1 mm. Not on 0,01 mm.
Lead block is possible use also for measurement longer charge in cavity 7 mm / 5g. With less exact results. Advantage of lead is his huge dynamic resistance of entire block.
But 5g require testing chamber minimal 70 x 70 x 70 cm with wet sawdust.

[Edited on 12-2-2022 by Laboratory of Liptakov]

MineMan - 12-2-2022 at 02:21

Quote: Originally posted by Laboratory of Liptakov  
Of course, that bigger amount will give more exact results and exact measurement of density. I estimate that 5g will enough. Diameter of high pressed EM of cylinder should by in this cause 12 - 15 mm at 5 g.
However alu brick must be a lot bigger. Which can be expensive. For 5g I reccomend using lead block of diameter 70 mm and 60 mm high.
Which is possible use repeatedly after casting. And measurement can be on 0,1 mm. Not on 0,01 mm.
Lead block is possible use also for measurement longer charge in cavity 7 mm / 5g. With less exact results. Advantage of lead is his huge dynamic resistance of entire block.
But 5g require testing chamber minimal 70 x 70 x 70 cm with wet sawdust.

[Edited on 12-2-2022 by Laboratory of Liptakov]


What do you mean dynamic resistance of lead is huge?

Laboratory of Liptakov - 12-2-2022 at 04:43

Lead is heavy. Test not need any solid pad for same repeatedly results. Lead block can be in any position at the test in chamber or sand pit. And "swim" there. Other on picture. For funny is there production special spoon for slow eating of soup.....:cool:

lead block.JPG - 1.1MB

MineMan - 12-2-2022 at 17:13

Quote: Originally posted by Laboratory of Liptakov  
Lead is heavy. Test not need any solid pad for same repeatedly results. Lead block can be in any position at the test in chamber or sand pit. And "swim" there. Other on picture. For funny is there production special spoon for slow eating of soup.....:cool:



That’s the only way I eat my soup. But I got a patent pal and my lawyer is gonna give you a call

Laboratory of Liptakov - 13-2-2022 at 03:31

Feel free to patent the hole spoon . By your advice (for UZP) was tested Lithex with 10% aluminium powder bright. Interesting is, the deep is exact same as without aluminium. 7,5 mm exactly. Complete energy of detonation was bigger according flying sawdust and other flying parts of testing chamber. Aluminium can provide advantage used less amount of Lithex for a same brizancion. And also for somes application, where is total energy importantly, than maximal brizantion. For example EFP not require maximal brizantion, there is more importatly maximal energy for better shaping of slug. Was observed also more easy filling - pressing behavior, resoectively pull of rod. If is Aluminium not critical compound, he provide clear advantage in mixture Lithex. Interestling...:cool:

MineMan - 13-2-2022 at 18:52

Quote: Originally posted by Laboratory of Liptakov  
Feel free to patent the hole spoon . By your advice (for UZP) was tested Lithex with 10% aluminium powder bright. Interesting is, the deep is exact same as without aluminium. 7,5 mm exactly. Complete energy of detonation was bigger according flying sawdust and other flying parts of testing chamber. Aluminium can provide advantage used less amount of Lithex for a same brizancion. And also for somes application, where is total energy importantly, than maximal brizantion. For example EFP not require maximal brizantion, there is more importatly maximal energy for better shaping of slug. Was observed also more easy filling - pressing behavior, resoectively pull of rod. If is Aluminium not critical compound, he provide clear advantage in mixture Lithex. Interestling...:cool:


Interesting test indeed! I am not surprised. Al always helps DDT . Now if you can source nano 100nm Al you will find your Lithex will DDT in 50-100mg, perfect for micro detonators.

Microtek - 22-2-2022 at 06:35

In case someone wants to experiment with urazine for themselves, I'm attaching the relevant pages from Inorganic Synthesis vol 4 here:

Attachment: Urazine pages.pdf (332kB)
This file has been downloaded 848 times


MineMan - 22-2-2022 at 14:07

Thank you Microtek! Any updates on the application of Urazine?

Microtek - 22-2-2022 at 23:12

I did a quick test of the use of urazine as a ligand in a Ni2+ complex with perchlorate anions. I dissolved Ni(NH3)6(ClO4)2 in hot water, added a little extra HClO4, and then gradually added two equivalents of urazine. This produces a very insoluble precipitate, that is only very slightly energetic. Wrapping it in Al foil and heating in a flame gives only a minute expansion of the foil package.
My hypothesis is that the precipitate is maybe nickel urazinate and not a complex at all.

Laboratory of Liptakov - 23-2-2022 at 01:28

Lithex is in a similar situation. Enclosed in foil during heating, in the end it always just burns. And still quite reluctantly.

Microtek - 8-3-2022 at 01:18

Recently, I have devoted my spare time to developing test methodology for measuring VOD using an oscilloscope. I can now report my preliminary findings:



PETN_d1.57_15mm.png - 32kB

This is a screencapture from a test on pure PETN with probe placement 15 mm apart. The probes are ionisation probes, with each probe simply consisting of two square cut copper leads inserted (the picture shows a single probe point):

Sleeve.jpg - 2.3MB

The test sleeve is resin 3d printed and the flaring base is just to have a secure attachment to the print plate. It also allows me to glue it onto a witness plate if I want to test brisance along with VOD (the axial hole goes all the way through). The picture doesn't do it justice, but the probe holes are very cleanly printed at exactly 5mm center distance.
The principle of this testing method is that the reaction zone just behind the detonation front is conductive since it is a high density plasma. Therefore, it can act as a switch to close a circuit. I have then constructed a simple circuit with the probes acting as switches in parallel and included a voltage divider setup to allow the change in signal to be detected, even if the conduction zone hasn't completely faded at one probe before triggering the next. The circuit is powered by a 9V battery, which provides the signal.

In the screen capture above, you can clearly see the very sharp rise in the signal as the detonation reaches the probe, followed by a gradual fall as the conductive zone attenuates. The time between the leading edges is very close to 2.5 us which, with probes 15mm apart, corresponds to a VOD of 6.0 km/s. It is difficult to assess this value since I don't know the exact density of the charge. Also, litterature values are often the result of tests on much larger charges, so even if I did know the density, the VOD of my charge would be less than most litterature values at the same value.
Nevertheless, I find the results encouraging.

I still have much work to do, examining the reproducibility of the setup and trying more than two probes to see if I can map the velocity profile. I also have to examine many different explosives to see if the detonation zone is similarly conductive for others.

[Edited on 8-3-2022 by Microtek]

Nitrosio - 16-3-2022 at 18:39

Attachment: BCHMX.pdf (1MB)
This file has been downloaded 287 times
Attachment: BCHMX2.pdf (750kB)
This file has been downloaded 245 times
Attachment: BCHMX3.pdf (1.2MB)
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Microtek - 19-3-2022 at 14:42

I think BCHMX is mainly interesting for thos who don't have access to acetic anhydride. If you can get just a small amount of Ac2O and P2O5, you can go the DADN -> SOLEX -> HMX route. All of the steps are easy, and gives essentially 100% yield. Look for the patents by Lukasavage.

Nitrosio - 22-3-2022 at 17:08

Glyoxal + (Amino)-Guanidine + Tetrazole... ???

Microtek - 24-3-2022 at 00:46

Take a look at this paper. The perchlorate salt is especially interesting IMO: d=1.99 (measured), VOD=9500 m/s and Pcj=45.7 GPa (Explo 5), Tdec=275C, IS=24J, FS=90N.

The friction sensitivity is perhaps a little high, but other than that, it is almost perfect. The question is if it is hygroscopic like so many other promising perchlorate salts.

Attachment: azotriazole salts.pdf (539kB)
This file has been downloaded 225 times


MineMan - 24-3-2022 at 01:20

Quote: Originally posted by Microtek  
Take a look at this paper. The perchlorate salt is especially interesting IMO: d=1.99 (measured), VOD=9500 m/s and Pcj=45.7 GPa (Explo 5), Tdec=275C, IS=24J, FS=90N.

The friction sensitivity is perhaps a little high, but other than that, it is almost perfect. The question is if it is hygroscopic like so many other promising perchlorate salts.


What is the synth like? Seems expensive involving silver?
Any update on the Urazine?

Microtek - 24-3-2022 at 07:48

The silver is not really necessary, just convenient, and would be recycleable anyway. The synthesis involves oxidative coupling using sodium dichloroisocyanurate (ordinary pool chem) and then reaction with triphenylphosphine which I need to buy.
Lately I have been working on The VOD measurements, so I haven't experimented further with urazine.

MineMan - 24-3-2022 at 23:29

Thank you Microtek!

greenlight - 29-3-2022 at 00:34

Full-nitro-nitroamino cooperative action: Climbing the energy peak of benzenes with enhanced chemical stability:

https://www.science.org/doi/10.1126/sciadv.abn3176


Here's the paper with the actual synthesis notes for TNTNB if interested:

Attachment: sciadv.abn3176.pdf (1.6MB)
This file has been downloaded 200 times

[Edited on 29-3-2022 by greenlight]

Microtek - 29-3-2022 at 03:20

Interesting, but IMO the decomposition temperature of 65C is a deal breaker (also the extremely high sensitivity).

MineMan - 29-3-2022 at 04:29

Quote: Originally posted by Microtek  
Interesting, but IMO the decomposition temperature of 65C is a deal breaker (also the extremely high sensitivity).


Microtek, how large were your UrazineP crystals and how would you compare the sensitivity to the nickel aminoguanidine perchlorate?

Microtek - 29-3-2022 at 22:10

The UZP crystals were about 0.1 mm (but of course a distribution of sizes), and the sensitivity of my NAP is much lower - I have trouble setting the NAP off with steel on steel hammer blows, whereas UZP detonates with firm taps under these conditions. My comments above were directed at trinitroaminotrinitrobenzene.

MineMan - 30-3-2022 at 02:24

Quote: Originally posted by Microtek  
The UZP crystals were about 0.1 mm (but of course a distribution of sizes), and the sensitivity of my NAP is much lower - I have trouble setting the NAP off with steel on steel hammer blows, whereas UZP detonates with firm taps under these conditions. My comments above were directed at trinitroaminotrinitrobenzene.


I know, I changed the subject a bit. Considering the issue UZP has in going full order, needing higher quantities do you see this as a practical material at all? Seems like it would be too sensitive then. Even handling a couple of grams of NAP is a serious decision.

Microtek - 31-3-2022 at 01:49

Well, I don't think the sensitivity issues are insurmountable - nitroglycerine is much more sensitive than UZP and has found quite a bit of use. I think the hygroscopicity is a bigger issue since the semi solvated UZP is VERY corrosive and might well be quite incompatible with other HEDMs or binders. Perhaps if we can find a suitably insensitive and non-hygroscopic perchlorate salt that might co-crystallize with UZP, or one that is melt-castable and forms a non-porous structure.

This is only really worth pursuing if the calculated performance can be realized, so I need to analyze what is going on with the low performance. For this, I need to fully develop my test setup for VOD and that requires a series of carefully identical tests to determine the reproducibility and accuracy of the measurements. Also, I need to see how my setup works with more than two probes, since this will be required to map the acceleration of the shock wave. That is what I'm working on at the moment.

MineMan - 31-3-2022 at 03:05

Quote: Originally posted by Microtek  
Well, I don't think the sensitivity issues are insurmountable - nitroglycerine is much more sensitive than UZP and has found quite a bit of use. I think the hygroscopicity is a bigger issue since the semi solvated UZP is VERY corrosive and might well be quite incompatible with other HEDMs or binders. Perhaps if we can find a suitably insensitive and non-hygroscopic perchlorate salt that might co-crystallize with UZP, or one that is melt-castable and forms a non-porous structure.

This is only really worth pursuing if the calculated performance can be realized, so I need to analyze what is going on with the low performance. For this, I need to fully develop my test setup for VOD and that requires a series of carefully identical tests to determine the reproducibility and accuracy of the measurements. Also, I need to see how my setup works with more than two probes, since this will be required to map the acceleration of the shock wave. That is what I'm working on at the moment.


Good thoughts microtek! Why not prepare a 10 gram sample of PETN and UZP and compare witness plates? Do you think Urazine periodate could have better stability?

Microtek - 31-3-2022 at 22:58

I do plan on some tests at a slightly larger scale, but I will begin at maybe 2 g. If the scale is in fact the problem, it should be possible to see some improvement by just increasing the diameter or the length of the charge a little bit. Before I do that though, I will map the VOD profile, since that should provide some clues as to the most effective improvements.

I don't have any experience with periodates (or easy access to them).

MineMan - 1-4-2022 at 02:38

I wait with anticipation!

Microtek - 3-4-2022 at 01:34

Here is the result of my first attempt with more than two probe points. The spacing is 10 mm between each pair. As can be seen from the screen shot, the time between the two first points is 1.45 us and between the second pair it is 1.60 us. This corresponds to VODs of 6897 m/s and 6250 m/s respectively. These values are reasonable for hand pressed charges of PETN with a small diameter (and with weak containment), but the fact that the second measurement is lower than the first is unexpected. Some possible explanations could be uneven charge density due to hand pressing, overdriven detonation from the primary, strange transient effects from reflection of shockwaves or maybe measurement error. Of these, I think the first is the most likely, since I didn't put much effort into consistent pressing.




PETN_ca_d1.6_10+10mm.png - 35kB

dettoo456 - 4-4-2022 at 08:08

Sorry since I’m not the best at understanding explanations without diagrams, but in your last post regarding the testing circuit, were the two probes set opposite of the charge on both ends (like a probe <-> charge <-> probe)? Or were they one probe behind the other, both being parallel to the charge (probe <-> probe <-> charge)? You may want to use piezos too; although they are more finicky and expensive but are used more often for this sort of VOD/pressure testing as they’ll ignore variability that can come with detonation products causing differences in plasma/heat formation. If my advice is retarded just ignore it (I’m no energetics wiz let alone electronics or sensitive circuit testing genius so a grain of salt is recommended as such) but good luck either way.
Also in regards to the hygroscopicity, core-shell-explosive design can be interesting regarding primaries and in this case the high VOD of UZP can overcome any small problems with polymer coatings such as n-methylpyrrolidone or poly-dopamine which can be easy to apply with just heat, solvent, and maybe some ultrasonic stimulation.

MineMan - 4-4-2022 at 16:31

Quote: Originally posted by dettoo456  
Sorry since I’m not the best at understanding explanations without diagrams, but in your last post regarding the testing circuit, were the two probes set opposite of the charge on both ends (like a probe <-> charge <-> probe)? Or were they one probe behind the other, both being parallel to the charge (probe <-> probe <-> charge)? You may want to use piezos too; although they are more finicky and expensive but are used more often for this sort of VOD/pressure testing as they’ll ignore variability that can come with detonation products causing differences in plasma/heat formation. If my advice is retarded just ignore it (I’m no energetics wiz let alone electronics or sensitive circuit testing genius so a grain of salt is recommended as such) but good luck either way.
Also in regards to the hygroscopicity, core-shell-explosive design can be interesting regarding primaries and in this case the high VOD of UZP can overcome any small problems with polymer coatings such as n-methylpyrrolidone or poly-dopamine which can be easy to apply with just heat, solvent, and maybe some ultrasonic stimulation.


Go on about the UZP….

Microtek - 4-4-2022 at 23:58

@Dettoo:

This test setup is like this: The charge is a coloumn of PETN or other substance. Down the side of the coloumn, two rows of holes are made at precise intervals (so two holes at the base of the charge, two holes 5 mm above this, two more holes above this and so on. See the photo for clarity). One probe consists of two copper wires inserted in a pair of holes at the same height. a 9V battery is connected along with a resistor to the wires (so one wire is positive, the other is negative, but because of the spacing between the two holes, the circuit is open). When the CJ-zone reaches the probe (remember that's a pair of holes), the conductive plasma closes the circuit and the voltage across the resistor increases. It is this rise in the voltage that is recorded by the oscilloscope.
I did consider piezo sensors (and also fiber optics), but seeing the crisp and clear signal from the ionisation probes, I don't see the need. I think that the micro scale I'm working at gives me an advantage because I can have the oscilloscope placed within one meter of the test. This means that I don't need long wires and problems with induced currents and lots of electronic noise.

I'm attaching another test, this time with 4 probes at 5 mm spacing. I have now figured out how to export the raw data from the scope, so I can make more precise calculations on the VOD. This time I used a 2.5 kg weight to compress the charge at small intervals to get as uniform a density as possible. This means that I only get 0.6 MPa of loading pressure, so the VOD is obviously going to be quite low. The average VOD between probe points are as follows:

5988 m/s between 1 and 2
5181 m/s between 2 and 3
4854 m/s between 3 and 4

(the first peak is quite small, but that is probably because the probe wire were not as firmly imbedded in the charge).
I think this indicates that the VOD actually does decrease down the charge, probably as a result of the weak containment, but I need some more tests to be certain.


PETN_0.6MPa_4probes.png - 34kB

[Edited on 5-4-2022 by Microtek]

Microtek - 9-4-2022 at 00:11

Reading through some papers and encyclopedias, I found that the critical diameter of any explosive is strongly dependent on particle size. Since mechanical sensitivity is also dependent on particle size, producing an ultra fine UZP batch may prove to improve both the dissapointing performance and address some of the sensitivity issues of UZP.
The problem is that it is not easy to do a particle size reduction based on crash precipitation (since dissolving UZP would freebase the urazine and UZP would only reform if all the water was removed). There is of course mechanical grinding, but that is not something I relish with a highly sensitive explosive. Maybe UZP can be ground safely under a non-polar solvent. I think I'll experiment a little at the milligram scale and see if I can make it explode under gasoline (with appropriate precautions obviously).

As an aside, particle size effects may also explain the observations on PETN, since a coarse grained charge that is weakly confined would be relatively close to its critical diameter (especially at low density, since critical diameter is also inversely dependent on charge density).

[Edited on 9-4-2022 by Microtek]

MineMan - 9-4-2022 at 09:44

Quote: Originally posted by Microtek  
Reading through some papers and encyclopedias, I found that the critical diameter of any explosive is strongly dependent on particle size. Since mechanical sensitivity is also dependent on particle size, producing an ultra fine UZP batch may prove to improve both the dissapointing performance and address some of the sensitivity issues of UZP.
The problem is that it is not easy to do a particle size reduction based on crash precipitation (since dissolving UZP would freebase the urazine and UZP would only reform if all the water was removed). There is of course mechanical grinding, but that is not something I relish with a highly sensitive explosive. Maybe UZP can be ground safely under a non-polar solvent. I think I'll experiment a little at the milligram scale and see if I can make it explode under gasoline (with appropriate precautions obviously).

As an aside, particle size effects may also explain the observations on PETN, since a coarse grained charge that is weakly confined would be relatively close to its critical diameter (especially at low density, since critical diameter is also inversely dependent on charge density).

[Edited on 9-4-2022 by Microtek]


Yes. I have suspected that the particle size was the reason for high sensitivity. Interesting about performance as well. Why can it not be crashed? Surly some solvent dissolves it? Is there any chance of making it in a larger bath of perchloric acid and instantly cooling? You could mix in with wax, 30 percent. Crush the wax mixture and dissolve the wax through a solvent??

Maybe lithium metal center would stabilize. Lithium Urazine perchlorate.

Microtek - 10-4-2022 at 04:38

It is not difficult to dissolve UZP, but if you do, the compound is destroyed. The problem is that urazine is more of an acid than a base, so it really doesn't want to form a salt with perchloric acid. By driving off the water, and because HClO4 is such a strong acid, you can make it do so anyway, but the second you dissolve it, they go their separate ways (so to speak).
It is possible that you can recrystallize it from hot concentrated perchloric acid, but I don't see an advantage in doing so.

dettoo456 - 12-4-2022 at 09:48

The only way to get the higher density required to achieve the stated properties is most likely melt casting (although most melt cast energetics can be suceptible to acid decomposition and on top of that melt casting primaries is a death wish) or something similar to anti-solvent recryst that might work for primaries or energetics in the booster range (think PETN, NHN-although insoluble, and tetryl). Basically, you might be able to use a dissolved energetic in a TLC sprayer under high N2 or Argon flow and spray onto a vertical or diagonal facing PTFE sheet. —> Like scraping spray paint particles off of a non stick surface to yield very small particulate. The sheet would have to be allowed to dry and hopefully the HClO4 would evaporate and the UZP would stick to the PTFE sheet. Scraping would also have to be very careful and use of a PTFE scraper could help tremendously. Good luck with whatever you try though and good luck trying to achieve those lofty m/s’s :D Don’t get yourself burned or scalded though

Microtek - 13-4-2022 at 13:26

I tried wetting UZP with detergent gasoline, and tested the sensitivity of the substance under these circumstances. I only did rather subjective tests, but found that I was not able to set off UZP under gasoline by grinding it in a porcelain mortar and pestle (I obviously only tested about 100 mg and wore protective gear). When placing about 50 mg of UZP wetted with gasoline in a fold of Al foil, it took determined pounding with a hammer on a steel anvil to set off small amounts of it. I would say that it is less sensitive than RDX when wet with gasoline. I will try grinding up some UZP a little at a time and test its performance to see if particle size reduction is a viable way forward.

@dettoo:
Actually, high density (above 2.0 g/cc) is easily achieved even with the large crystals. Ordinary pressing is all that is required.

MineMan - 16-4-2022 at 14:21

Any news microtek? If you do a VOD test on the ground UZP also do a witness plate as we cannot verify the accuracy of the VOD quite yet.


MineMan - 18-4-2022 at 07:53

Primary explosive with a sensitivity of 10J impact and 120N Friction. Also thermally stable to 350C

Can anyone grab and post the paper or talk about the synth? It’s basically a primary explosive with less sensitivity than RDX!

https://onlinelibrary.wiley.com/doi/full/10.1002/prep.202200...

Microtek - 20-4-2022 at 08:02

That synth is easy, but requires a quite exotic pyrimidine to make one of the precursors. They describe it as "commercially available", but I don't think you will find it other places than in lab supply shops. I think I'll be sticking to AGNiP.

In other news, it seems my hypothesis about the critical diameter of the rather coarse UZP was correct.
I ground up a little more than one gram of it under detergent gasoline. I did it in small portions to reduce the seriousness of any accidental initiation from the grinding, but nothing untoward happened. After drying in a dessicator, I was left with a fine white powder.
Previously, I had designed and CNC machined a couple of fixtures for supporting the brass tubes that I'm doing my brisance tests in (and another for the VOD test charge holders). This was necessary because the unsupported brass tubes expand under pressure, making the density of the charge difficult to calculate. These new holders are very solid, and fit the tubes in a light interference fit, meaning that the brass tubes can only expand a few micrometers.

Anyway, I pressed the powdered UZP into the tube at a quite high pressure, and easily got it well above 2 g/cc. When detonated, it produced a dent of 4.64 mm depth. The coarse UZP at a similar density made a 2.91 mm dent, so the simple act of pulverizing increased the performance by almost 60%. This dent depth is greater than for any of the other explosives I have tested, so the question is now if I can overcome the hygroscopicity.

Laboratory of Liptakov - 20-4-2022 at 11:19

Great results, Microtek. 4.64 mm is incredible the depth. How much provide ETN ? My ETN 1g give at density 1.69g/cc depth 5,34 mm. In alu block.
But diameter is 8 mm. (Against your 7?) Lithex gived depth 4.17 / 1.4g/cc. Lithex is also very hygroscopic. But is not crucial problem, because after filling is isolated in metal cavity. For main charge it can be problem. For detonator less.

MineMan - 20-4-2022 at 12:48

Quote: Originally posted by Microtek  
That synth is easy, but requires a quite exotic pyrimidine to make one of the precursors. They describe it as "commercially available", but I don't think you will find it other places than in lab supply shops. I think I'll be sticking to AGNiP.

In other news, it seems my hypothesis about the critical diameter of the rather coarse UZP was correct.
I ground up a little more than one gram of it under detergent gasoline. I did it in small portions to reduce the seriousness of any accidental initiation from the grinding, but nothing untoward happened. After drying in a dessicator, I was left with a fine white powder.
Previously, I had designed and CNC machined a couple of fixtures for supporting the brass tubes that I'm doing my brisance tests in (and another for the VOD test charge holders). This was necessary because the unsupported brass tubes expand under pressure, making the density of the charge difficult to calculate. These new holders are very solid, and fit the tubes in a light interference fit, meaning that the brass tubes can only expand a few micrometers.

Anyway, I pressed the powdered UZP into the tube at a quite high pressure, and easily got it well above 2 g/cc. When detonated, it produced a dent of 4.64 mm depth. The coarse UZP at a similar density made a 2.91 mm dent, so the simple act of pulverizing increased the performance by almost 60%. This dent depth is greater than for any of the other explosives I have tested, so the question is now if I can overcome the hygroscopicity.


Fantastic news! It far outperforms RDX! Can you try the ground UZP with 15 percent aluminum as that boosted performance of the large crystals?

MineMan - 20-4-2022 at 12:55

Quote: Originally posted by Laboratory of Liptakov  
Great results, Microtek. 4.64 mm is incredible the depth. How much provide ETN ? My ETN 1g give at density 1.69g/cc depth 5,34 mm. In alu block.
But diameter is 8 mm. (Against your 7?) Lithex gived depth 4.17 / 1.4g/cc. Lithex is also very hygroscopic. But is not crucial problem, because after filling is isolated in metal cavity. For main charge it can be problem. For detonator less.


According to microtek picric acid had a depth of 3.73 and RDX 4.14… so the difference in power of UZP to RDX is more than RDX to Picric acid. This is extraordinary, truly a new class.

Microtek would you be willing to give Urazine dinitramide a try? There must be a better ion than perchlorate? I am determined to find someone to try Urazine periodate.

Importantly but not mentioned. How did the mechanical sensitivity change with the ground UZP, should be safer

[Edited on 20-4-2022 by MineMan]

Laboratory of Liptakov - 22-4-2022 at 07:19

If will for UZP confirms the repeatability of production and the repeatability of brizance, the reliability of DDT and so on, it will be a great benefit in the field of amateur research. And due to the brizance almost a revolutionary invention.

Microtek - 27-4-2022 at 08:19

I haven't measured the mechanical sensitivity in any rigorous manner, since I am not really satisfied with the methods I have available. My impression is that it is somewhat less sensitive when finely ground, but then, that is the case in general so it would be strange if it wasn't for UZP.
I did prepare a plastique containing 93% UZP and 7% binder/plasticizer, and left it in the open in my lab at a relative humidity of 40% and a temperature of 23C. After 3 days, the mass has increased by about 3%, so there is some hygroscopicity, but under these rather dry conditions, it is manageable. I have now moved the sample to a room with 55% relative humidity, and will monitor the moisture absorption over the coming days.

Also, I have done a test of the repeatability of my VOD setup. I made a batch of PETN based plastique with 10% binder/plasticizer (I chose plastique because it has good flow properties under moderate pressures) and took three samples of exactly one gram each. These samples were each pressed into a VOD sleeve similar to the one I posted about earlier (I updated the design to use Dupont pin connectors for the probe points. They have a shoulder a certain distance from the point, so it is easy to insert them to the exact same depth). I pressed the charges in a vice and approximated the same loading density (1.6 g/cc) by monitoring the overall length of the assembly (digital caliper), and pressing to within 0.1 mm of the same length. I pressed 300mg pure PETN on top and 50mg AGNiP on top of that.
Then I inserted three probes with 5mm spacing and initiated electrically (bridgewire).
The VOD was measured to 8425, 8147 and 8646 m/s respectively, giving a mean velocity of 8406 m/s, so a variability of +- 260 m/s but also an apparent overestimation of the velocity which should have been in the 7700-7900 m/s range. Still, the variability of the measurement was only +- 3% and a systematic overestimation can be corrected for. I will experiment with greater spacing between probes, but even at the present state I think it is time to test UZP, probably in a polymeric matrix like the PETN.

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