Microtek
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Boron containing molecular explosives
First of all, let me say that this is pure speculation and may not be possible at all.
I stumbled across a link on google about ways to store hydrogen or ammonia for space applications, etc. They proposed, among other things, borazine
and cyclotriborazane. Borazine is an analogue to benzene, with alternating N and B atoms in the ring. Cyclotriborazane is obtained by reducing
borazine, and is an analogue to triazacyclohexane. Now, the electron distribution in these systems means that electrophiles will preferentially add to
the nitrogens in the ring, so what about adding some nitronium ions to obtain analogues to trinitro benzene or rdx ?
Borazine is a rather unstable and volatile liquid ( bp ca 53 C ) and reacts with water, acids and alcohols as well as light, but cyclotriborazane at
least does not react with water and is crystalline.
I did some VERY rough calculations on energy release from the rdx analogue and found that it would probably be ridiculously powerful ( of course there
are still the question of density and stability ).
Any opinions ?
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chemoleo
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Nice idea. Will check books on that later.
In fact I thought about similar compounds using carbon-linked silicon derivatives. Here the energy output should be decent, too!
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Organikum
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silanes ?
Are these not called silanes, Chemoleo?
I read about these compounds some time ago - for use as car-fuel and for rockets....
The boron sounds also interesting so..
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chemoleo
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yes, for instance (O2NO-CH2)4Si (the silane analogue of PETN) should be interesting. The reason why I said, C-Si linkage, as this is more energetic
than the admittedly more common C-O-Si linkage, which you find in silicon plastics...
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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BromicAcid
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Okay, let's give it a whirl! I've made trichloroborazine before and it's simple and with a little modification we will find out if we
can do a trinitroborazine.
3BCl3 + 3NH4Cl ---> (-BCl-NH-)3 + 9HCl
That was the reaction that I did, borazine's are not terribly sensitive to light you just don't want to store them in it.
Where did I get the boron trichloride you ask? Well, I tried to make boron by reduction of boric oxide with aluminum powder, so I heated boric acid
till it turned glassy and mixed with aluminum powder. After a beautiful thermite reaction it turns out it makes quite a bit of aluminum boride which
is a highly inert material, especially if you're trying to separate the boron from it. After numerous failures I tried reacting the mixture
product with chlorine gas at slightly elevated temp and got a distilate of boron trichloride, I made the borazine derivative because I had nothing
better to do with it.
Anyway, I do not know the mechanism of the reaction but maybe swapping NH4NO3 for the NH4Cl might throw a nitro group or two on there, if not we might
have to reduce it to the pure borazine, but how many of us have access to sodium borohydride? IF we did have the pure compound it reacts instantly
with dilute HCl to make the trichloride, I imagine it would have an analogous reaction with nitric acid.
Fun stuff eh?  I'd be tempted, but... well... it's cold out side.
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BromicAcid
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Well, I searched Beilstein and Gmelin on the network at my college, I could find no evidence that any trinitro compounds of borazine have been
synthesized. But I did find B-tris(azido)borazine. (BN3NH)3 and I read an interesting article work in the inorganic chemistry journals titled
"Synthesis, Characterization, and Exposive Properties of the Nitrogen-Rich Borazine [H3N3B3(N3)3]"
However the preparation is quite outside of anything most of us could accomplish. But I don't see much of a reason why the trinitro compound
could not be attempted. Straight borazine treated with 100% nitric should theoretically yield [H9N3B3(NO3)3] (well if the nitric didn't oxidize
it first and it would have to be anhydrous since water hydrolyzes borazine quite readily...) which could be CAREFULLY heated where it would pyrolize
to the [H3N3B3(NO3)] or maybe go about it another way by reacting [NH2NO2] with diborane to yield [H3N3B3(NO2)3] directly.
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BASF
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"of course there are still the question of density and stability"
stability...why not! 
density...i believe it is difficult to make a borazine with much higher D than 1.3-1.5...although this would be quite a start, i think. I believe the
main-handicap for a borazine-explosive is still the low density.
BromicAcid: what is the density of H2N3B3(N3)3? any properties known? i´m very curious.
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BromicAcid
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B-tris(azido)borazine (BN3NH)3
Crystal Structure:
Crystal System: Triclinic
Lattice Length A: 8.579 Angstroem
Lattice Length B: 9.182 Angstroem
Lattice Length C: 12.043 Angstroem
Lattice Angle .alpha. 104.62
Lattice Angle .beta. 90.26
Lattice Angle .gamma. 110.74
Temperature 20 Deg C
Method of Determination Single Crystal X-ray Diffraction
Molecules per Unit Cell 4
X-Ray Density: 1.584 g/cm3
Space Groups: 2
Explodes on mechanical shock or friction; stable towards human electrostatic discharge
Soluble in Et2O, THF, MeCN, CH2Cl2; Slightly Soluble in C6H6, PhMe, Hexane
Melting Point: 152 - 153 C
Reactions for production:
3NaN3 + (-BClNH-)3 ---> 3NaCl + (-BN3NH-)3
Yield: Not Stated
Or:
(-BClNH-)3 + 3(CH3)3SiN3 ---> (-BN3NH-)3 + 3Me3SiCl
Yield 97%
I don't know why I said the procedure was outside something us here at sciencemadness can do, it is made so simple by the fact that you can use
the B-tirchloroborazine produced from the inital reaction of boron trichloride with ammonium chloride, no in-between reduction step with sodium
borohydride necessary!
Edit: Equations not balanced... 
[Edited on 2/17/2004 by BromicAcid]
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