Energetic Perovskites

There is scattered information regarding these on this forum, but i thought it better to consolidate this into one thread.

Energetic perovskites are as the name suggests energetic double salts that form in a perovskite structure. From what I can find in the literature only DABCO (1,4-diazabicyclo[2.2.2]octane or triethylenediamine) and piperazine (diethylenediamine) are known to form these, with a variety of nitrate, perchlorate and periodate salts. Other amines are listed in the patent US 20190112242A1 but I believe it's just to cover all the bases just for patent purposes, excuse the pun.

Theres some pretty wild performance figures shown in the literature, which is all out of China. The rhetoric from the early reports has been toned down slightly but still is in the high 8000's and into the 9000's for velocity of detonation and likewise high det pressure. The current highest performing is "DAP-6" which is Hydroxylamine Dabconium Triperchlorate with a calculated figure of 9123m/s and 38.1GPa det pressure.

I have made DPPE-1, DAP-2, DAP-4, DAN-2 and experimented with swapping out the KNO3 in DAN-2 with NaBrO3 and KClO3. These are all DABCO based which is a fairly common industrial and lab chem but not OTC. Piperazine is available OTC as poultry dewormer, quite cheaply. Here its available as piperazine citrate solution or as the solid dihydrochloride at the equivalent of about $60US per Kg. This will need to be freebased as the piperazine perovskites seem to be significantly soluble, I attempted to use the dihydrochloride as is but could not form a precipitate.

DPPE-1 is a primary explosive but interestingly it seems the DAP-2 and DAP-4 will likewise act as initiating explosives even though they only deflagrate in the open. I'm only basing this assertion on the supporting info available here https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.2023026... , I cannot access that main article. If anyone can that would be great.

The downside to these perovskites is that they seem to be quite friction sensitive, which is attributed to there rigid perovskite structure.

Heres a description of what my results were.

Potassium Dabconium Trinitrate (DAN-2)

(H2DABCO)[K(NO3)3]

11.2g (0.1mol) DABCO and 10.1g (0.1mol) potassium nitrate is dissolved into 50ml of water, then 18.5g (0.2mol) of 68% nitric acid is added in one portion with stirring. This resulted in a slight exotherm that raised the temperature to 38 degrees C. The solution was left stirring for 5 minutes then left to stand at an ambient temperature of 18 degrees C. Crystalisation began at about 20 degrees C and proceeded at the stable temperature of 18 degrees C as a moderate yield of needle shaped crystals. These were shown to be only very feebly energetic. The mother liquor was left to stand for one day, whereby it redissolved the needles through the heat of the sun, then deposited large blocky crystals as the solution cooled throughout the 14°C night, these were filtered and dried.

As far as I can determine both crystal forms were the same thing and DAN-2 has no notable energetic properties. When held in the jet of a butane gas flame it turns black then burns weakly and splutters putting itself out. Nothing even remotely close to the "modern blackpowder" as claimed in the literature. A vacuum was applied to the seemingly dry crystals for 2 hours but the energetic properties were not improved.

Attemps to substitute KNO3 with NaBrO3 failed, there was no precipitate but on placing the solution in the sun to evaporate I believe bromination took place from the breakdown of HBrO3, fine yellow needles precipitated in high yield that were only mildly energetic.

Attempts to substitute KNO3 with KClO3 produced a precipitate of ill defined crystal form that deflagrated vigorously leaving white pearls. I believe this to be more a coprecipitate than a perovskite.


Potassium Dabconium Triperchlorate (DAP-2)

(C6H14N2)[K(ClO4)3]

2.77g of potasssium perchlorate in 100ml water was heated with stirring at 50°C until dissolution. Another solution comprised of 2.24g of DABCO in 100ml and 5.74g of 70% perchloric acid was then poured into the stirred potassium perchlorate solution resulting in an immediate milky precipitate. The heating was turned off and the solution was stirred for another 30 minutes as it cooled to 25°C before filtering, flushing on the filter with ethanol and drying.

On ignition DAP-2 flares vigorously with a fsssshhhht emitting a large lilac tinted flame leaving a small amount of white residue. It explodes readily with a violent report when struck with moderate force with a hammer on anvil, suggesting a far higher impact sensitivity then the 16J reported.


Ammonium Dabconium Triperchlorate (DAP-4)

(C6H14N2)[NH4(ClO4)3]

A solution is made by dissolving 4.48g (0.04mol) of DABCO into 10ml water and 11.48g (0.08mol) of 70% perchloric acid then left to stir for 5 minutes. Another solution is made of 4.7g (0.04mol) ammonium perchlorate in 10ml of water (or 2.72g 25% ammonia and 5.48g 70% perchloric acid). The two solutions are combined at room temperature with stirring resulting in an immediate white precipitate, stirring is continued for 10 minutes then it is filtered, flushed on the filter with ethanol and dried for a yield of 16.0g (93% of theory).

When ignited DAP-4 deflagrates vigourously with a jet like flame leaving no notable residue. DAP-4 is readily detonated with a moderate hammer strike on an anvil again suggesting a far higher then reported impact sensitivity.

Ammonium Sodium Didabconium Hexaperiodate (DPPE-1)

2C6H14N2.2Cl + NH4Cl + 6NaIO4 --> {(C6H14N2)2[Na(NH4)(IO4)6]}n + 5NaCl

2.24g (0.02mol) DABCO and 0.54g (0.01mol) ammonium chloride in 50ml water is neutralised with 4.56g (0.04mol) 32% hydrochloric acid, into this at room temperature and whilst stirred was added 12.8g (0.06mol) sodium periodate in 80ml water. An immediate white precipitate formed, stirring was maintained for 3 minutes then the white solid was filtered, flushed with a further 50ml of cold water and dried.

DPPE-1 is a very vehemic compound, detonating violently in >10mg type quantities when touched with a flame and easily initiated with a hammer on steel which is quite odd for something based on periodate. Here's a video comparing 5mg quantities of DPPE-1 with cyanuric triazide and NAP https://www.sciencemadness.org/whisper/files.php?pid=697407&...


Attached is a picture of DAP-2, these precipitate immediately as small cubes. The DAP-4 and DPPE-1 look the same but smaller.


[Edited on 19-12-2024 by Axt]



[Edited on 19-12-2024 by Axt]

Quote: Originally posted by MineMan

Are any of these derivatives secondary explosives with moderate or insensitive properties? Or no because of the structure?

Quote: Originally posted by Axt

Here's DAP-4, according to the Chinese this is 153% less sensitive than TNT.

Yeh so had a look at that article mentioning initiation efficiency, here's the results they obtained. So yes DAP-4 will act as quite an efficient initiator when used over 30mg. DDPE-1 was published later the same year and is the best at sub 5mg to initiate RDX. I've shown 5mg DPPE-1 being ignited in open in first post, I'll attach a pinch of DAP-4 being ignited here as you can see DAP-4 and DAP-2 are pretty tame unconfined.

In the picture DAP-0 is dabconium diperchlorate, DAP-1 sodium dabconium triperchlorate, DAP-2 potassium dabconium triperchlorate, DAP-3 rubidium dabconium triperchlorate and DAP-4 ammonium dabconium triperchlorate. It's interesting that the ammonium salts have the highest initiation efficiencies. TDPI's are the exact periodate analogues to the perchlorates, their efficiency is also unexpectedly better than perchlorates, their VOD's are significantly lower but they reach their peak pressure quicker.



Attachment: DAP-2 and DAP-4 ignition.mpg (6.7MB)
This file has been downloaded 117 times

A picture is worth a thousand words. Using a lead witness plate is one of the best measurements. By making a dent or hole in the lead, it is possible to measure power with high accuracy. I consider the "plate dent" method, i.e. a dent or crater (in the lead) to be the most accurate amateur measurement. The method used in the picture is not so accurate because part of the energy disappeard through hole. As a result, part of the information is lost. Exact method here for example:

Oh yes. It was only research of amount of primary weight.....

DAP-4's hygroscopicity is discussed in the article attached above.

 "Different from the most perchlorate-containing salts, DAP-4 has a
very low hygroscopicity. Our studies indicated that, according to the
Chinese GJB772A-97 test standard, the samples of DAP-4 showed only
ca. 0.01% weight change (i.e., almost unchanged) under the relative
humility of 91% at 30 C for 3 days. A comparison study reported by Cao
et al. revealed that the hygroscopicity of DAP-4 is only about 10% of that
of AP under the same condition (vide infra)."

It does not feel in any way hygroscopic but does have a distinct tendency to clump and keep its shape when moulded which I was putting down to its crystal form or maybe some other attraction between crystals. I would expect pressing it into pellets would be very easy. It was hard to get an image under the microscope as they all want to bunch together a cluster of DPPE-1 is attached.

No I have never tried to confine it.

Quote: Originally posted by Axt

The double salt of ethylenediamine diperchlorate and triethylenediamine diperchlorate (DABCO) was measured in J. Ener. Mat. (2017) 35:4, 443, 8956m/s @ 1.873g/cm3. "tested by a ZBS-10A100 MHz intelligent ten segments detonation velocity measuring instrument at room temperature".

Quote: Originally posted by Axt

Guanidine perchlorate VOD is 6000m/s at sp gr 1.15, and 7150m/s at 1.67. 6 G152 Methylamine perchlorate VOD is 7540 m/see at d 1.68 and 6600 at d 1.565. 1 A227 Triaminoguanidine perchlorate VOD is 7730m/see (d 1.56g/cc) 9 T28

Healthy scepticism is warranted, particularly for reports coming out of China. My only criticism is the talking in absolutes. I'm personally not a fan of high reported figures of simple perchlorate salts, it just takes the fun out of it.

They calculated a heat of formation of +563kJ/mol for the en/DABCO tetraperchlorate which seems absurd (although not as absurd as the initial reported 1904kJ/mol for DAP-4). This wouldn't affect (supposed) measured values though. This is a topic where the amateur can provide more credible information.

Quote: Originally posted by Axt

They calculated a heat of formation of +563kJ/mol for the en/DABCO tetraperchlorate which seems absurd (although not as absurd as the initial reported 1904kJ/mol for DAP-4).

Quote: Originally posted by Axt

Guanidine perchlorate VOD is 7150m/s at 1.67 Methylamine perchlorate VOD is 7540 m/see at d 1.68

Quote: Originally posted by Axt

The double salt of ethylenediamine diperchlorate and triethylenediamine diperchlorate (DABCO) was measured in J. Ener. Mat. (2017) 35:4, 443, 8956m/s @ 1.873g/cm3.

Quote: Originally posted by Axt

Enthalpy and heat of formation are the same thing not the inverse.

Quote: Originally posted by Axt

It'd be most interesting to throw these up against the other purported high velocity salts aminotetrazole nitrate and aminonitroguanidine nitrate which as far as I know have no experimental values.

Quote: Originally posted by Microtek

We have run into this language barrier before,

Quote: Originally posted by Microtek

That must be a very strange textbook. Axt is correct in saying that "heat of formation" = enthalpy, and both are equal to the energy flow INTO the system required to form the substance from elements. That means that substances that release energy when formed such as CO2 from C and O2 will have a negative heat of formation. This is obviously just a matter of definitions - it would have been possible to define enthalpy with the opposite signs, but the way Axt refers it is the consensus in the scientific community. And certainly the way it is presented in the textbooks I have read.

Quote: Originally posted by Etanol

Hmm, I looked at the tables for TNT, RDX, PETN, HClO4 and Ethylenediamine. The authors used determination "Heat of formation" = “Enthalpy of formation”, but a typo really takes place for ETT.

It's not a "typo", it's reiterated in the text. A positive number is an ongoing trend for the purely amino based double salts with the first (seemingly outrageous) numbers published in 2018, but toned down by 2023. The calculations are given in the supporting information linked to in first post.

Quote: Originally posted by Axt

It's not a "typo", it's reiterated in the text. A positive number is an ongoing trend for the purely amino based double salts with the first (seemingly outrageous) numbers published in 2018, but toned down by 2023. The calculations are given in the supporting information linked to in first post.

DPPE-1 update

13 Months ago I´ve synthesized several small batches DPPE-1 for testing. A major concern is long-term stability. So I decided not to use all for sensitivity testing, but also for storage stability testing.

Quantities between one and two gram were covered with several milliliters distilled H2O, and stored in a tool shed outside of my house. The temperature was in the winter close to zero and reached in the summer about 25 to 30 degree centigrade.

All batches were prepared from the same precursors, even same batch of precursors, but showed different behaviour. One batch remained almost unchanged, virtually no discoloration, still pourable and goes ddt in small quantities.

The next batch was considerably discolored, with crystal growth and agglomeration, not pourable. It gave small flashes in the blue bunsen burner flame, really tame, but no explosion at all.

The last (third) sample seems halfway between the former two. Slight discoloration, somewhat clumpy and a very fast burning with flash and a "whomp" but no bang.






This sample still works fine:






This is the other end:






"Intermediate", halfway between the former two:






I thought that similar prepared samples should behave in the same way? I still have no idea what went wrong. Maybe slight differences in the stoichometric composition? Or the precipitate not enough washed? The pale amber color looks like traces of iodine due to degradation.

Any other ideas?