Post by Anders Hoveland on Mar 18, 2012 0:05:15 GMT -8
A quick summary of the calculated properties of DTTO will be provided: DTTO Calculated Density: 1.97 g/cm3 Calculated Detonation Pressure: 558-567 kbar Calculated Velocity: 10.28 km/sec = 10280 meters per second! Formula: C2N8O4 [1,2,3,4-tetrazino-1,2,3,4-tetrazine]-1,3,6,8-tetraoxide / Ditetrazinetetroxide (there are actually two different structural isomers)
DDTO has not yet been reportedly prepared, although there have been several attempts made by researchers, who have calculated that DTTO would generate pressures of 558-567 kbar, and that is the downward revised calculation, because the previous ones were thought to be unrealistically high. For comparison, octonitrocubane, which is generally regarded as the most powerful explosive possible, is calculated to generate pressures of 489 kbar. RDX produces only 346 kbar of pressure and HMX produces 390 kbar.
It should be noted that the unusual dioxy-tetrazine rings on DTTO have been synthesized into stable compounds, so DTTO should not be seen as completely theoretical. Dioxy Tetrazalo-benzene (Benzene-1,2,3,4-tetrazine 1,3-N,N-dioxide) has been prepared and is stable, having a melting point of 172-174 degC. It should be mentioned that any other arrangement of the two oxygen atoms on the tetrazine is not stable, although the unstable mono-oxide can be stored for 6-7 hours)
Post by Anders Hoveland on Mar 18, 2012 0:19:16 GMT -8
Karl Christe and his team has actually prepared 1,3-dioxytetrazolofuroxan (with one more oxygen atom. Although it has been prepared, the explosive properties of 1,3-dioxytetrazolofuroxan have never been reportedly measured, but using some basic calculations, I have estimated the detonation pressure of this explosive at around 406 kbar.
Reaction of 4-nitroso-5-aminofurazan with tert-butyl-dibromamine, (CH3)3C-NBr2, transforms the nitroso group (-N=O) into the intermediate, -N[+](-O[-])=N-C(CH3)3, with an azoxy bridge joining a tert-butyl group. This is then reacted with NO2BF4 (this site has a section for the preparation of this obscure regent). This transforms the amino group into –N=N[+]=O, (in 52% yield) with the concurrent additional formation of nitrite, NO2[-]. This intermediate spontaneously cyclizes to form a 1,2,3,4-tetrazine-1,3-oxide ring, with the furazan now adjoining the tetrazine ring. (Note that NO2BF4 needs to be used. Use of N2O5 instead only oxidizes the amine group to a nitro) Reaction of 4-nitroso-5-aminofurazan with tert-butyl-dibromamine, (CH3)3C-NBr2, transforms the nitroso group (-N=O) into the intermediate, -N[+](-O[-])=N-C(CH3)3. This is then reacted with NO2BF4 (this site has a section for the preparation of this obscure regent). This transforms the amino group into –N=N[+]=O, with the concurrent additional formation of nitrite, NO2[-]. This intermediate spontaneously cyclizes to form a 1,2,3,4-tetrazine-1,3-oxide ring, with the furazan now adjoining the tetrazine ring. Churakov, Tetrahedron, 1995
I was thinking about the possiblity of just following the established procedure for forming tetrazine rings, but do it on a 1,2,3-triazole scaffold instead of the furazan scaffold that is described in the research above. Then one could essentially just do a ring opening to obtain the double adjoining tetrazine rings.
A similar ring opening reaction has already been described by researchers. It works for forming 1,2,3-triazines, perhaps it may [hopefully] work to form the 1,2,3,4-triazine also.
"1,2,3-Triazine was obtained by nickel peroxide oxidation of N-aminopyrazole." "1,2,3-Triazine". Akio Ohsawa, Heihachiro Arai, Hidefumi Ohnishi, and Hiroshi Igeta, J. Chem. Soc., Chem. Commun., 1981, 1174-1174
lead tetraacetate is supposedly not sufficient as the oxidizer in this specific reaction, although from a quick search of the literature, the reaction using lead tetraacetate as the oxidizer apparently works for other derivitives of N-aminopyrazole)
"Nickel Peroxide" probably refers to nickel dioxide, and supposedly can be prepared by reacting a nickel oxide with potassium persulfate.
To give some idea of the oxidizing strength of nickel(IV) oxide, NiO2 + 4H[+] +(2)e[-] = Ni[+2] + (2)H2O , E0 = 1.593V
Post by Anders Hoveland on Mar 18, 2012 0:22:12 GMT -8
excerpt from diagram in attachment below:
furazano-1,2,3,4-tetrazine-1,3-dioxide "Oxadiazolo[3.4-c][1,2,3,4]tetrazine 4.6-di-N-oxide (35) is obtained as a yellow crystalline compound (melting point 110-123degC with decomposition) by reaction of the amine derivitive (44) with excess nitronium tetrafluroborate in acetonitrile at (minus) -20degC. Compound 35 is very sensitive to shock and, although it can be stored for long periods at 0degC, it should be handled with care." NO2BF4 must be used, not N2O5, because the inermediate appears to be reactive toward the nitrate anion, which then results only in oxidizing the amino group to a nitro group, rather than formation of a new dioxytetrazine ring.
Bu(t) (with a little "t") means a tert-butyl group, with the structure --C(CH3)3
Post by Anders Hoveland on Mar 18, 2012 0:26:33 GMT -8
1,2,3-Triazoles are surprisingly quite easily oxidized. Nitration of 4-nitro-1,2,3-triazole, for example, results not just in 4,5-dinitro-triazole, but in fact 4,5-dinitro-triazole-1N-oxide. So the the treatment with NO2BF4 that is used to form the initial tetrazine ring would simultaneously oxidize the adjoining triazole ring.
My idea can be seen in the attachment below.
The resulting triazolo-tetrazine tri-N-oxide would subsequently be treated with O-hydroxylamine sulfonic acid, NH2OSO3H, which would add an amine to the 3-position of the triazine ring. Then react with nickel dioxide, NiO2, causing a ring opening with formation of [1,2,3,4-tetrazino-1,2,3,4-tetrazine]-1,3,6-trioxide (with one less Oxygen atom than DTTO).
Of course, this would have to be oxidized in the next step without delay, because the mono-(1-N)-oxide of benzotetrazine reportedly can be kept for 6-7 hours before decomposition to benzofurazan and nitrogen gas. (If you were curious, unoxidized benzotetrazine, without any oxygen atoms, is too unstable to be isolated)
The [1,2,3,4-tetrazino-1,2,3,4-tetrazine]-1,3,6-trioxide would immediately be oxidized with HOF to finally obtain DTTO. A typical procedure using HOF as the oxidizer is briefly described below,
Nitrotetrazole can also be oxidized by HOF, transiently formed in solution by passing elemental fluorine into a cold liquid acrylonitrile solvent in the presence of a lesser quantity of water. "The Tetrazole 3-N-Oxide Synthesis" Tal Harel, Shlomo Rozen, School of Chemistry, Tel-Aviv University, Tel-Aviv, Israel. J. Org. Chem., 2010, 75 (9), pp 3141–3143
This forum already contains information about the preparation of 1,2,3-triazoles and for nitronium tetrafluoroborate, NO2BF4, so these regents are not covered in this post. (see the ammonium dinitramide topic)