[HEDM]

The dinitramide anion was found by the soviets since 70s however the first report on dinitramide synthesis in the west was reported by SRI-International in 1993.

Coded SRI-14 by the SRI international, they planned to synthesize hydroxylammonium dinitramide, not knowing a compound with the most insane crystal density packing was about to be made(If you check the current proposed future green oxidizer - Ammonium dinitramide's elemental analysis to this compoud, the hydrogen content and density is almost insane!)
They synthesized the compound could simply known as Hydroxylammonium-hydroxylamine-dinitramide, it's crystal packing tells another story. This compound have all of the three possible forms of hydroxylamine - protonated, neutral, and zwitterionic, and the extensive and strong intermolecular hydrogen bond ultimately gave this compound the high density.
therefore we can also call the compound Dihydorxylammonium-hydroxylamine-azaneoxide dinitramide.
This compound have the highest hydrogen density in NHO compounds I have ever seen that still have excess oxygen to spare. With so much more hydrogen content than ADN, it beats ADN's density by 0.5gm/cm3 which is incredible. Its insane cyrstal density comes from the complex network of hydroxylamine-azaneoxide-hydroxylammonium dinitramide network.
Formula =
[H3N+O-] [[NH3OH+]2]2+ [HONH2] [[N(NO2)2]2]2- Empirically N10H14O12.
contains the hydroxylamine entity in all of its three possible forms; protonated, neutral, and zwitterionic. The O----H protons for the two protonated (NH3OH)moieties are involved in very strong hydrogen bonding
interactions to both the zwitterionic (H3N+O-) and neutral (NH2OH) moieties, essentially forming associated dimers. In the former case this bond is to O¡ (H-O, 1.406A° ) while in the latter case the hydrogen bond is to N (H-N, 1.451A° ). For these hydroxylamine moieties all of the hydrogen atoms participate in one or more hydrogen bonds.
The reason why it is so amazing is simple - It produces much more gas than the currently proposed future green energetic oxidizer ADN, the oxygen balance is good, it is much denser than ADN. Its production cost is also likely to be lower than ADN due to the less weight of dinitramide anion needed to be synthesized, and finally, the specific impulse, impulse density, will give will be much much higher than ADN, if from ammonium perchlorate to ADN is a new stage of efficiency, this compound is definately a new level and posses great potential. The reported Impact sensitivity was said to be ''more impact sensitive'' than ADN. However I personally believe the purifies and finally prilled(sphrical) and preferably coated final product will be very suitable for aerospace use. Maybe making this compound into nano powder can also cover up its high impact sensitivity, which is seen in Nano HMX to normal HMX, the impact sensitivity decreased from 6.5J to 15J-20J.

[Borek]

Any particular reason to copy/paste this part of the original document?

[HEDM]

No I actually typed this.

[Borek]

Google shows this particular text also on facebook.

[Enthalpy]

If you provide a heat of formation (accurate to 10cal/g), I can tell how good (or bad, most often) this N₁₀H₁₄O₁₂ is.

However, many thousands of compounds were proposed as propellants, but only 4 combinations are used because all others are unuseable or worse. For instance, the shock sensitivity of nitromethane rules it out, or the toxicity of fluor compounds, the cost of boron compounds. Methane was considered, but against its 11s improvement, users prefer the hard-to-light kerosene.

There is also a general move to liquid oxygen, instead of solids or storable liquids. I know that some oxidizers, as ionic liquid or solids, made the buzz in the recent years, but once you check their performance, it's a huge disappointment. Obviously not worth it, and one may ask whether further work is justified.

Even in tiny thrusters used for attitude control at landers or satellites, storable liquids will disappear. Satellites have electric propulsion more and more, and I've proposed techniques to store and cool cryogenic propellants, light the reaction in the chamber, pump the propellants electrically, produce cooling jackets - everything needed to switch to liquid oxygen.

Density is interesting on a launcher but far less than the specific impulse - one of the many differences with explosives, they shouldn't be taught together. Other mundane considerations that decide if a propellant is usable: is it brittle? What is its pressure exponent? What proportion of elastomer versus crystal does it take in the mixture? (Al+NH₄ClO₄+polybutadiene needs too much elastomer to fill the voids, sinking its performance - a hint that the oxidizer should provide much oxygen). How dangerous to manufacture, prior to use?

So don't be too disappointed if rocket designers don't adopt every new compound.

This holds for launchers mainly. Atmospheric weapons relax the need for performance and accept more varied propellants. Over a common formulation, nitrocellulose plus nitroglycerine, improvement is still possible.

[HEDM]

Google shows this particular text also on facebook.

Thats because I also typed that.

[HEDM]

If you provide a heat of formation (accurate to 10cal/g), I can tell how good (or bad, most often) this N₁₀H₁₄O₁₂ is.

However, many thousands of compounds were proposed as propellants, but only 4 combinations are used because all others are unuseable or worse. For instance, the shock sensitivity of nitromethane rules it out, or the toxicity of fluor compounds, the cost of boron compounds. Methane was considered, but against its 11s improvement, users prefer the hard-to-light kerosene.

There is also a general move to liquid oxygen, instead of solids or storable liquids. I know that some oxidizers, as ionic liquid or solids, made the buzz in the recent years, but once you check their performance, it's a huge disappointment. Obviously not worth it, and one may ask whether further work is justified.

Even in tiny thrusters used for attitude control at landers or satellites, storable liquids will disappear. Satellites have electric propulsion more and more, and I've proposed techniques to store and cool cryogenic propellants, light the reaction in the chamber, pump the propellants electrically, produce cooling jackets - everything needed to switch to liquid oxygen.

Density is interesting on a launcher but far less than the specific impulse - one of the many differences with explosives, they shouldn't be taught together. Other mundane considerations that decide if a propellant is usable: is it brittle? What is its pressure exponent? What proportion of elastomer versus crystal does it take in the mixture? (Al+NH₄ClO₄+polybutadiene needs too much elastomer to fill the voids, sinking its performance - a hint that the oxidizer should provide much oxygen). How dangerous to manufacture, prior to use?

So don't be too disappointed if rocket designers don't adopt every new compound.

This holds for launchers mainly. Atmospheric weapons relax the need for performance and accept more varied propellants. Over a common formulation, nitrocellulose plus nitroglycerine, improvement is still possible.

You can try searching it in this paper.

http://link.springer.com/article/10.1023%2FA%3A1011362427996

If it is not there, I predict it to be around -200. Try calculating with -200.

The specific impulse might not be too high, but its density impulse should be much higher.

[Borek]

Any particular reason to post this text in both places?

[HEDM]

I am just raising awareness of potential crystal packing hydroxylamine salts or its hydroxylamine hydrate could achieve.

[Enthalpy]

I've run Propep on this oxidizer (does it have a manageable name?), with your -200cal/g (right unit?) heat of formation, and the raw performance would be very interesting even for a launcher, provided we still want solids.

I compared with Vega's Zefiro 23 engine, with the same expansion from 95bar to 0.5bar (hence in a graphite fibre casing), and the same astounding 12% of elastomer fuel (=polybutadiene).

69% NH₄ClO₄ - 19% Al - 12% Htpb give isp=2814m/s and 3590K
88% competitor - 0% Al - 12% Htpb give isp=2888m/s and 3137K
66% competitor - 22% Al - 12% Htpb give isp=3043m/s and 3639K

229m/s=23s gain are worth changing the habits. More so to get rid of chlorine.

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I also checked it as an independent gas generator that rotates a turbine, in the same conditions as
http://saposjoint.net/Forum/viewtopic.php?f=66&t=2272&p=43869#p43869

100% competitor alone give isp=2497m/s and 2614K, too hot for a turbine
56% competitor - 44% water (gelled?) for +700°C give isp=1197m/s from 50bar to 5bar
that's 100m/s less than caustic amines: discussable.

66% competitor - 34% water for 1100°C (hypothetic molybdenum turbine) give 1392m/s
again 100m/s less than caustic amines.

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So if one wanted to keep solids in a launcher, your oxidizer would be convincingly more efficient - BUT please keep in mind that rocket designers want
(1) Safety
(2) Safety
(3) Safety
(4) If it burns, that's better, but not too easily please.

Presently, solid mixes for launchers can ignite just from an open flame, possibly from a spark, and then the whole plant detonates (see youTube). That's the concern #1 at solid stages.

Then, your oxidizer must have a pressure exponent <<1 to be useable. It's the decomposition speed versus pressure, which compares directly with the behaviour of a nozzle, hence tells stability.

Of course, it must be technically manageable... Presently polybutadiene is vulcanized at RT after mixing with the powders, and ammonium perchlorate has the good will not to ignite with the chemical agents. The result is not very brittle (a crack is deadly), and can adhere to the casing, and so on, and so forth.

And, yes, cost does matter.

So please keep a cool head about new propellants - very few candidates come through.

[HEDM]

How do you add a new compound to PROPEP code? I wanted to do that, but I wasn't sure of how.

This new compound, is just 1 compound out of many that I know, that could replace NH4ClO4(AP).

And I personally do not think this is the brightest next-generation oxidizer, but I was here just to give an example of the high density hydroxylamine's salt and its own hydroxylamine hydrate could do.

BTW, for the unit for HOF of the compound, I meant to say -200 kj/mol. Although It might be closer to around -100kj/mol.

[Enthalpy]

Propep takes easily new compounds, and can be used in abnormal ways, that's why I didn't switch to convenient software like LRA (a free version exists), which is less touchy, more recent and quicker
http://propulsion-analysis.com/

Just edit propellant.dat as any text, preferibly with an editor that can use a fixed width font, like Courier New in Metapad
http://liquidninja.com/metapad/download.html

For instance your unpronounceable compound:
    2120 HEDM's thingy                  14H  12O  10N   0    0    0   -200 .0000]

- Where you want, one line per compound (must be a Fortran program)
- The line number doesn't matter
- ALIGNMENT does matter! Imitate existing compounds.
 Beware this forum may remove spaces in my message.
- Compound name is rather free.
- Atoms in any order
- cal/g (here mistaken -200cal/g instead of -200kJ/mol)
- Optional density in pound per cubic inch

Unit converter for Win : SIKonverter (Ger and Eng) http://si-konverter.giga.de/
or there http://joshmadison.com/software/convert

I join my propellant.dat, so you see how heavily edited it is. Remove the txt extension before unzipping. My additions are at the top.

An accurate heat of formation is necessary to evaluate a propellant. 10cal/mol uncertainty biasses already the comparisons.

[Enthalpy]

[snip] I personally do not think this is the brightest next-generation oxidizer, but I was here just to give an example of the high density hydroxylamine's salt and its own hydroxylamine hydrate could do. [snip]

I have no firm opinion about what shall replace ammonium perchlorate in solid grain. Dinitramides' performance is better, but safety comes first, process adequacy second.

The near bright future I see for energetic compounds is, dissolved in water or maybe some alcohol or amine, as an auxiliary gas generator that rotates the turbopump(s) for the main propellants:
http://www.scienceforums.net/topic/82965-gas-generator-cycle-for-rocket-engines-variants/#entry805364

Most often a secondary, detuned mix of the the main propellants burns in an auxiliary chamber to rotate the turbopump(s), is this is harder to start (Soyuz is an exception). I'd have a graphite-fibre pressure vessel holding a separate, unpumped propellant to power the turbo-pump. Then, a monopropellant is better and can differ from the main propellants.

This auxiliary monopropellant (liquid or solid) must provide lukewarn gas (600-700°C for nickel alloys, maybe 1100°C with molybdenum as I suggest) at high speed. Dinitramides, being very soluble in water and (flammable!) methanol, have a decisive advantage over nitrates. I had to mix a fuel (diamino-guanidinium-nitrate) with ammonium dinitramide and water to get performance; if feasible, diamino-guanidinium-dinitramide would improve, or a similar compound a bit fuel-rich.

[HEDM]

Alright, Ill try to figure out how to make a new compound in PROPEP, i am a program-blind person. I mean, I don't know anything in this field - computer related things.

I read your idea on a good propellant, I do agree your idea is better than many existing liquid engines and that mono-liquid-propellant could reduce the overall complexity of the machine, etc.

Some of my recent ideas on favorable propellant formulation

Note - (I'm just going to type this in rush, and if i make a lot of grammar mistakes, try understand it, ill edit tomorrow when I have a nice rest)
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Interesting. I still believe solid is the answer to heavy duty launchers.

We can't use nuclear or solar sails on earth, only in space, due to the risk, pollution, etc etc. Plasma, electric, gas accelerators like VASIMIR, etc, produce low thrust only feasible in deep space.
Therefore Solid will have a very bright future if the Specific impulse could be reached.

"A 1% increase in specific impulse increases the ICBM range by 365 nautical miles (for a 5000 nautical miles ICBM) or more than 7%. A 5% specific impulse increase results in a nearly 45% range increase..."
-S. S. Penner, The Chemistry of Propellants: A Meeting Organised by the AGARD Combustion and Propulsion Panel.

Solid > Liquid in terms of complexity, and therefore cost of casing, machining, and overall safety. Liquid engine also have a much lower Fuel-payload ratio or Fuel-Casing ratio. If we can just add for example 10 seconds of impulse to SRB's, the paylaod would increase a lot.

I am not only talking about dinitramides. Solid fuels are also in great advance.
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A line to separate my idea, I read your idea about dissolving the compound in water and dissolve another fuel for a mono-liquid-propellant. Not too bad, but honestly the Isp is could not exceed 300 due to the water in the solution. I have personally tested the first propellant that dissolves an oxidizer, where the solvent is cured, into a polymer, and the amount of oxidizer is dissolved in the ''cured'' solution could provide enough oxygen for the entire system to combust.

I published this last year, I'd work on better oxidizers next time on this idea. I was just showing that such idea is possible -
http://article.sapub.org/pdf/10.5923.j.aerospace.20140301.01.pdf

Any way, I think the future to solid propellants could be low molecular weight exhaust producing salts or compounds.

Carbon, chlorine, etc, from HTPB and AP produce high molecular weight exhausts and therefore results in low Isp. So to combine these 2 advantages of solid and liquid, we might need to find a high Hydrogen or nitrogen weight fuel along with high oxygen and hydrogen density oxidizer. So our goal is find solid compounds with maximum Hydrogen, oxygen, nitrogen content by weight, in this order. We should avoid or make least out of carbon. For example, Hydrazine is a very good liquid fuel because it's cost is low, burns to form only nitrogen and water, which have low molecular weight. Amazing. However its salts and its hydrates of its own salts, which is solid, might be better, for example -

Hydrazinium azide hydrazinate = (+N2H5)(N3-)•(N2H4) or empirically N7H9, contains 91.5% nitrogen by weight. With a density at around 1.3g/cm3, would serve as an amazing solid fuel in replacement of aluminum.
http://onlinelibrary.wiley.com/doi/10.1002/1521-4087(200110)26:4%3C161::AID-PREP161%3E3.0.CO;2-O/abstract

This compound is also insensitive to shock and is very safe. It's also not hygroscopic, which is desirable. However many other properties such as compatibility with binders are not yet reported, although I predict to be compatible with most binders.

And for replace of aluminum, aluminum hydride is also promising, direct replacement of aluminum to aluminum hydride result in much higher burn-out velocity.
See this post I made -
http://www.sciencemadness.org/talk/viewthread.php?tid=29786

Now another solid salt which is interesting - Hydroxylammonium-hydroxylamine-nitrate. (NH3OH)+ (NO3)- •(NH2OH).
Reported here - http://pubs.acs.org/doi/abs/10.1021/i360030a021

Might be interesting. The density is high for the amount of gas it can produce which is - 1.7g/cm3. The salt is reported the be non-hygroscopic, and maybe, I wish, to be insensitive and safe.
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Now if we combine these 2 compounds, (NH3OH)+ (NO3)- •(NH2OH) with (+N2H5)(N3-)•(N2H4), or empirically (N3H7O5) and (N7H9), we can make an oxygen balanced mixture at molar ratio of 3:1.

The product it produces would be (N3H7O5)3(N7H9)1 > Combust > 8N2 + 15H2O. Which is 54.7% Water.

If we took N2H4 with liquid oxygen, it would be N2H4 + O2 > Combust > N2 + 2H2O. which is 56.3% Water.

The molecular product of the exhaust is almost the same, however the solid one have a density of around 1.6, while the liquid would be 1.1

See the advantage of the solid here?

That'd be my final objective in researching on this field :p

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So yeah, the most favorable propellant additive need to need to have these properties-

large amount of low-molecular-weight exhaust,
have good heat of formation for higher combustion temperature.
Low shock, electric, flame sensitivity
Able to be produced on industrial scale
compatibile with modern and energetic binders/plasticizers

[Enthalpy]

The solid-versus-liquid debate is little technical and very much a matter of which company, state or country supplies the market. In the USA, it was even a decision by congressmen that the SLS would use solids. In Europe, the choice is biassed right from the beginning. In addition, strong liquid engines existed essentially in the Soviet Union.

Fact is that every single recent cheap launcher (Falcon, Zenit, and some Chinese coming up) has liquids everywhere.

Vega was to be cheap thanks to solids and efficient with its graphite fibre casings, but now this small launcher is as expensive as a medium-class liquid like Falcon.

In the launch cost, one must factor the production and operation risks. A plant storing 500t or 3000t of explosive stuff sensitive to flame or sparks is a huge and costly risk.

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Hydrazine is an extremely bad propellant because it's risky. Performance won't rehabilitate it. Huge efforts are under way to replace it. Can you produce your hydrazinium compounds without using hydrazine at the plant? If not, it's a bad idea, even if the final product is a nonvolatile solid.

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The real criterion about a propellant, once it's safe and useable, is the specific impulse. While hydrogen is desired, there is no fixed preference between nitrogen and carbon - it all depends on the combustion enthalpy per mass unit, and the ease of gas expansion (gamma). CO (solids use to produce little CO₂) is as light as N₂. And Al₂O₃ has the worst possible mass per gas mole for being a solid, but it's very useful because it brings heat, so the comparison isn't very easy.

The stress put on density and on nitrogen proportion relates with explosives and missiles. Launcher propellants have different needs. "Energetic compounds" shouldn't be taught together.

Yes, aluminium hydride is interesting, but with a limited gain. Aluminium lithium hydride as well. They must be protected; one researcher proposed thin aluminium shells around each hydride speck. Available in Propep, so just make a few comparison runs.

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My objective with aqueous solutions of energetic salts is not to challenge the specific impulse of the main engines. Other people try it, and are very far from that goal - I expect it will stay so, because H-O bonds have nothing to do in an unburnt propellant.

Rather, I propose to produce that way the secondary flux for the turbine. Here the needs are a regular and predictable low temperature, no solids (no soot) in the gas, and only once this is met, a high expansion speed - in this particular use, water has its place and dissolved dinitramides seem to be a good choice.