1,4-Diformyl-2,3,5,6-Tetranitropiperazine

1,4-Diformyl-2,3,5,6-Tetranitropiperazine is a new primary explosive based on glyoxal.

Firstly, 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine is synthesised by reacting 2 glyoxal ( HOC-COH ) molecules with 2 molecules of formamide ( COH-NH₂ ) in H₂O at a pH of 9.

Then, 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine is nitrated by 100% HNO₃ with trifluoroaceticanhydride as the solvent.

All is carried out with an icebath and after the last step the solution is allowed to warm up to ambient temperature under stirring.

1,4-Diformyl-2,3,5,6-Tetranitropiperazine seems to form rather small crystals, as the authors of the article needed several recrystallisations to get crystals that were suitable for X-ray diffraction.

1,4-Diformyl-2,3,5,6-Tetranitropiperazine is a primary which is sensitive to shock, but only deflagrates violently when heated.

What strikes me is the use of trifluoroaceticanhydride as a solvent for nitrating. Apart from using it to create N₂O₅ I wonder if they specifically use it to avoid any addition reactions on the ring structure?
Or maybe because it isn't flammable?

This information comes from the JoPEP nr1, 2003.
3D molecule was drawn by me using Chem3D Ultra.

To clarify, the little pink bubbles beside the oxygen atoms are lone electron pairs.

[Edited on 9-3-2003 by vulture]

Hmm, Afraid to post because it sounds complicated? This should be a fairly easy compound to prepare, especially if you keep in mind that the TFAA and 100% nitric acid aren't really necessary. Remember, this comes from a published research article, which means the authors will use the most sophisticated and highest yielding method since they're only analysing small amounts.
This is not a batch synthesis procedure.

C'mon guys...

Hmm, not sure what to say about this, as I'm a bit of a novice in the area of Organic Chemistry and have little experience with Explosives .

I suppose one way to make Glyoxal could be to use some strong dessicant on Formic Acid... Vague, yes, but I can't think of specifics at the moment...just laying the ground works for this .

As for Formamide... would reacting a Formyl Halide with Ammonia work to create Formamide?

COHCl + 2 NH3 --> COH-NH2 + NH4Cl

I have no idea about the Trifluoroacetic Anhydride, so I'm not going to say anything about it...to hopefully avoid making an ass of myself .

It seems that glyoxal is a very useful chemical to have around! This, TENGU, HNIW... loads of good things need it.
Formamide can be made by reacting formic acid with ammonia and then dehydrating it with something like P2O5 I would have thought, or maybe by heating ammonium formate with H2SO4.
But unless anyone can find an alternative to TFAA, or a reference which says it isn't needed, then I'll stick to lead azide .

My "sources" say that glyoxal can be made by oxidizing ethanol or acetaldehyde (ethanal) with nitric acid.
I do not have any specific procedure though.

Mr Samose, I don't see how one could make glyoxal from formic acid, as glyoxal has 2 carbon atoms -> HOC-COH
Or do you mean a condensation reaction?

I think the TFAA could be substituted by something else. They probably used it to avoid any side reactions.

This is just the first reported preparation, so there's no doubt more simple methods will be discovered.
Then we might actually making some progress Mr Samosa!

Actually, I was thinking of simply dehydrating Formic Acid to make "Formyl Anhydride," if that is the correct nomenclature for the product...

But just now do I realize my mistake- this would not be the desired product! oops

As for oxidizing Ethanol, do you suppose that reaction could work by creating Nitric Acid in situ using Sulfuric Acid and Potassium or Ammonium Nitrate? If this is the case, then this would certainly be the easiest way to go about obtaining Glyoxal. The hell with Acetaldehyde, because not everyone can get such things .

Trifluoroacetic anhydride has a low bp and is easily removed as the acid; you thus need less heat to efficiently remove under vaccuum the solvant; also with such sensitive HE primaries, it is a good idea to keep the stuff cool when isolating!
TFA acid is a very strong inoxydable acid!
What puzzles me is that there is no mention of nitrolysis of the formyl moiety!

The use of TFA acid anhydride seem not to be needed!As the same kind of reactions should occure well in 100% HNO3 or HNO3/acetic anhydride!

O=C-NH2 + O=CH-CH=O + NH2-CH=O --> O=CH-NH-CHOH-CHOH-NH-CH=O
O=CH-NH-CHOH-CHOH-NH-CH=O + O=CH-CH=O --> O=CH-N(CHOH-CHOH)2N-CH=O

Then reacting with HNO3 yields tetranitrate ester (you thus have a kind of dimeric EGDN and the hability of easy cristallisation owing to amide moiety) --> suspected sensitivity equal to PETN/MHN and VOD close to that of MHN!Excess OB from the NO3 is compensated by the end O=CH-!

What would be much more interesting would be to do would be to do the same reaction after hydrolysis of the O=CH-N(CHOH-CHOH)2N-CH=O that should yield HN(CHOH-CHOH)2NH that is one of the product of the condensation of glyoxal with NH3 (2mole/2 mole)!
Then action of HNO3 conc should yield:
1,4 dinitro-1,4 diaza-2,3,5,6 tetrol-cyclohexane tetranitrate O2N-N(CHONO2-CHONO2)2N-NO2

The condensation of glyoxal with NH3 yield (3moles/4moles):

CHOH -CHOH
NH NH
CH -CH
NH NH
CHOH -CHOH

That is a good precursor of the HE:

CHONO2-CHONO2
O2N-NH N-NO2
CH -CH
O2N-NH N-NO2
CHONO2-CHONO2

Also interesting alternative to formamide are carbamate ester CH3-O2C-NH2, (CH3)2N-CO-NH2, HO-NH2, NH2-NH2, NH2-CO-NH-NH2, NC-NH2, O2N-NH-CO-NH2, O2N-N=C(NH2)2, (NH2)2C=NH and (NH2)2C=O!

An couple of alternative preps, not using TFAA are in GB Pat 1042905 (1966)

TFAA is often used in situations where having a non-nucleophillic anion as a by-product (ie CF3COO-) is an advantage. Don't forget that nitration with TFAA or acetic anhydride works through CF3COONO2 or CH3COONO2, not nitronium ions - these species are not very good at nitrating N-acyl moeities.

Hey, Philou - long time! - don't think many of your alternatives to formamide would work, my friend...all those hydroxyls are too prone to oxidation to have anything except an electronegative partial pi-bonded substituent on the nitrogen atoms. The urethane (H2NCOOEt) and the N,N-diemthylurea might work, but I don't see much advantage.

HHTDD !

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HHTDD