Sciencemadness Discussion Board

AN/Hexamine "adduct"

E-tech - 5-3-2008 at 18:47

Recently came accross US patents 3,247,033 and 3,166,452.
The inventor claims that either a melt or carefully measured crystalization process can result in an adduct of AN and hexamine, which shows noticable improvement when compared to physical blends of the two components, or any deviation from his patent instructions.
I wonder, is this adduct just an in situ formation of hexamine dinitrate, or is the compound formed something different?
Anyone out there have a bit more experience with this type of material? (adducts in general, or hex/AN blends)?

PHILOU Zrealone - 6-3-2008 at 05:16

On a molecular level if you can allow the "over oxydised" NH4NO3 to mix with the low OB (oxygen balance) (CH2)6N4, you will end up with an oxygenated equilibrated mix of NH4NO3/(CH2)6N4.2HNO3 (some NH3 is maybe lost during the cristalisation process). So you get:
1°)a low T° melting mix (eutectic) vs the mp of the two separated compounds...what can be good for casting.
2°)more detonable than NH4NO3 because HeDN is more sensitive and higher power explosive than NH4NO3
3°)more energy output because of the balanced oxygen and for sure a higher VOD than both ingredient appart.
4°)a better sensitivity than AN owing to the HeDN moiety and so a tinier critical diameter of detonation than AN alone.
5°)a cheaper compound than HeDN alone

So almost only benefits :cool::P;)

[Edited on 6-3-2008 by PHILOU Zrealone]

Boomer - 6-3-2008 at 10:19

Whether there is a double decomposition or not I do not know, it seems likely. BTW is hexamine a stronger base than NH3?

To my knowledge for the power it should matter little, since a melt-cast of AN/fuel will behave as an ideal explosive, versa the non-ideal behavior of ANFO type explosives, that have an ideal density above which VoD drops again and critical diameter rises. But it will influence how easily detonable the stuff is.

Does anyone know if this is valid for all AN melts, or only for the ones where the other component(s) is/are energetics themselves, like the AN/EDDN type or the mixes I tried 2 years ago, melting far below 100C and punching clean holes in 5mm steel plates. Those were with HDN, UN, GN, ... and 10-20% RDX. Without the latter they would not shoot in 1" dia (cast of course), I never looked into trying them as rocket propellants. Would definitely surpass candy propellants, at moderate risk. In fact, they could be poured at temps that epoxy or PU bound AP composites reach while hardening.

"... tinier critical diameter of detonation than AN alone" Good joke! Are several inches tiny? :P

[Edited on by Boomer]

E-tech - 6-3-2008 at 16:28

it's possible that the cast HDN, UN, and GN experiments could work without the addition of the RDX. Maybe including 0.5 - 5.0% addition of microballoons could be sensitizer enough to work. The non-ideal behaviors of ANFO type explosives has been improved using emulsion technology- fun stuff to study- I'd like to try them (having already worked with water gels), but I don't know if a kitchen blender can give the shear rates needed to form a good emulsion!

"tinier critical diameter"- I thought that was funny, too. I've seen research that shows pure AN's detonation ability is directly related to a comparison between the particle size and the charge geometry. Not really worth pursuing for only 5000ft/sec.

According to the patent, the formation of the "adduct" would only take place at specific mixing ratios, which, after it's formation was complete, was then mixed with additional AN to bring the mix to a better oxygen balance. Trying to form the adduct with the excess of AN appearantly failed when the patent holder tried it.
is the adduct a product of crystallization in a specific pattern?

pdb - 7-3-2008 at 06:14

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