The reaction of dinitrotriazole with sodium azide to form compound (B) requires heating to 120C, nitrogen is evolved and NaNO2 byproduct results.
Compound (B) can also be oxidized with ammonium persulfate to form FTO (compound C).
Furoxanyltriazole oxide (FTO), with the formula C2N5HO3, could potentially exceed HMX in performance, while being a safer explosive, being more resistant to impact. Unlike molecules of HMX, the smaller molecules of FTO would be expected to pack together more densely due to intermolecular hydrogen bonding. FTO would also probably be more thermally stable than HMX. For a high performance explosive, the molecular structure of FTO is somewhat unique in that there are no nitro groups. Not only is FTO expected to be more stable than nitramine explosives, but FTO might also be more stable than some of the nitroaromatic compounds.
Another name for furoxanyltriazine oxide (FTO) could be oxytriazolofuroxan. Looking at the molecular structure of FTO (C2N5HO3), it seems that this compound would probably be slightly more energetic than 1,1-diamino,2,2-dinitro ethylene (DADNE) (C2N4H4O4), which has a detonation velocity as high as 8870 m/sec. DADNE is another example where hydrogen bonding lends high density to a small molecule (1.63 g/cm3). The velocity of DADNE is greater than that of RDX, but less that for HMX, which has a velocity of 9.1 km/sec.
The importance of hydrogen bonding influencing the density of energetic compounds should not be underestimated.
3-nitro-1,2,4-triazol-5-oxide (C2N4H2O3), despite having only a single nitro group, with the third oxygen not being "functional" (since it is double bonded to a carbon), nevertheless has a high detonation velocity approaching 8.6 km/sec because of its unusually high density for such a small molecule, 1.93 g/cm3, which is slightly higher than the density of HMX (1.91 g/cm3). Another comparison could be made with 3-amino,5-nitro-1,2,4-triazole (ANTA), formula C2N5H3O2, which has a density of 1.82 g/cm3 and a velocity approaching 8.5 km/sec. These velocities are not quite as high as RDX
(8.75 km/sec), but nonetheless demonstrate that hydrogen bonding leads to high densities, even for smaller molecules.
Possible Synthetic Routes
There are several possible routes for production of FTO. An ideal one would utilize regents that are inexpensive in bulk, and would involve as few steps as possible. Unlike many other "performance explosives" that surpass HMX in explosive performance, the preparation of FTO could be less complicated and thus viable for industrial production.
These are only prelimary ideas, please correct any mistakes, or provide your ideas for modifications of the procedures. I do not know if FeSO4, which under alkaline conditions is known to reduce picric acid to picramic acid, could reduce dinitro-1,2,3-triazole to 4-amino,5-nitro-1,2,3-triazole. The NH group in the ring, which serves as an electron donor to both nitro groups, might make the dinitrotriazole incapable of oxidizing the ferrous ion.
Unfortunately, all attempts to nitrate unsubstituted 1,2,3-triazole using mixed acids have failed, even under rigorous conditions. (there does exist a clever way to directly nitrate it, however, but the procedure utilizes obscure regents)
Apparently nitroacetone can be used to make nitrogenous rings, supporting my idea that nitroacetone should be able to condense with sodium azide to form 4-methyl,5-nitro-1,2,3-triazole.
"One-pot synthesis of 5-nitropyridines by the cyclocondensation of nitroacetone, triethyl orthoformate and enamine" Galina P. Sagitullina, Anna K. Garkushenko, Evgeny G. Atavin, and Reva S. Sagitullin
Department of Organic Chemistry, F. M. Dostoevsky Omsk State University, 644077 Omsk, Russian Federation
Could one perhaps condense CH2O and excess nitromethane (using the nitroaldol condensation reaction, simply heat with NaOH) to make nitroethanol (which is poisonous and easily absorbs through skin)? Then oxidize nitroethanol with a selective oxidizer such as 2-Iodoxybenzoic acid (no water can be present or the nitro group will disproportionate off from the acidity in a Meyer reaction) or pyridinium chlorochromate. This would then form 2-nitroacetaldehyde O2NCH2CH=O.
This could then potentially cyclize with sodium azide to form plain 4-nitro-1,2,3-triazole, without the methyl group that would have resulted if nitroacetone had been used. Possibly heating in concentrated nitric acid (100degC) could simultaneously oxidize the methyl group to a carboxyl, then decarboxylate the molecule, and finally add a nitro group in. While plain 1,2,3-triazole cannot be directly nitrated, 4-nitro-1,2,3-triazole is more susceptible.
At least for benzoic acid, decarboxylation proceeds readily by heating (only 100degC) if there is another electron withdrawing group (such as a chlorine atom) on the ring. (this would result in chlorobenzene and carbon dioxide).
Some information about 2-Iodoxybenzoic acid: it can oxidize methanol to formaldehyde in 94% yield, and can similarly oxidize ethylene glycol (vehicle anti-freeze) to glyoxal. However, dimethyl sulfoxide (DMSO) can not be used as a solvent for the latter, as its pressence will cause the ethylene glycol to be oxidized to formaldehyde instead. The 2-Iodoxybenzoic acid can then be re-oxidized and recycled after completion of the reaction.
2-Iodoxybenzoic acid can be prepared by the slow addition, over a half hour, of potassium bromate (76.0 g, 0.45 mol) to a vigorously stirred sulfuric acid mixture (0.73 M, 730 mL) containing 2-iodobenzoic acid (85.2 g, 0.34 mol).
Here is the nitroaldol condensation procedure between nitroethane and CH2O. A lesser ammount of nitromethane could very easily substitute for the nitroethane:
75.1g Nitroethane, 0.3g calcium hydroxide and 80g 40% formaldehyde solution was dissolved in 75ml ethanol with stirring and was allowed to stand for 48h at room temperature. Distillation at 100-105°C/13 mmHg (85-86°C/6 mmHg, 99°C/10 mmHg) gave 48g 2-nitropropanol (46%) and 14.3g of 2-nitro-2-methyl- 1,3-propanediol, the latter remained as a crystalline residue in the distillation flask after distillation of the 2-nitropropanol.
The condensation of chlorobenzene with plain triazole would be extremely slow (months) without a catalyst. Using dinitrochlorobenzene or bromobenzene as the starting regent would be much more rapid. Paradichlorobenzene (some types of mothballs) that has gone through a nitration could also be used.
As for oxidizing furazans to furoxans, furazans are very resistant to oxidation. I am sure that I read somewhere that it is possible, involving concentrated H2O2 and H2SO4, but I cannot find the reference so this could be incorrect. In the same paragraph of the source as I remember, it mentioned that oxidizing furoxans to two vicinal nitro groups is nearly impossible.
Here is the procedure for turning an adjacent amino and nitro group into a furoxan ring:
A mixture of 21 g. (0.32 mole) KOH and 250 ml of 95% ethanol in a 1L flask is heated on a steam bath until the solid dissolves. 40 g. (0.29 mole) of o-nitroanaline (where the amino and nitro groups are beside eachother on the benzene ring) is dissolved in the warm alkali solution. The resulting deep red solution is then cooled to 0°C, and sodium hypochlorite solution (made with 50g NaOH, 200mL water, which has absorbed 0.58 moles of chlorine gas) added slowly with good stirring over the course of 10 minutes. The yellow precipitate is collected on a large funnel, washed with 200 ml of water, and air-dried. The crude product weighs 36.0–36.5 g. and melts at 66–71°C. The product is purified by recrystallization from a solution made up from 45 ml. of 95% ethanol and 15 ml of water. the material is that is insoluble in the hot solvent is removed by filtration, and the hot filtrate is allowed to cool to room temperature. The yield of yellow benzofuroxan is 31.6–32.5 g. (80–82%), m.p. 72–73°.
Nitromethane and acetaldehyde react in the presence of sodium carbonate to form 1-nitro-2-propanol. This can then be oxidized into nitroacetone. Nitroacetone may be extracted with ether, and has a normal boiling point of 152 degC, or 105 degC at 25mmHg (reduced pressure).
25g nitropropanol and 37.5g sodium dichromate are mixed in 25mL water. 35mL of 60% sulfuric acid are then slowly and periodically added to the solution over a period of 4 hours, keeping the temperature below 14 degC at all times.
A dark green crystalline substance was then extracted from the solution using ether. Crystals of nitroacetone form after the ether evaporates. The crystals are then recrystallized from methanol (to give a purer product). The resulting nitroacetone from this procedure melts at 46 degC. Solid nitroacetone is unstable in air, but it is stable as an ether solution away from prolonged exposure to sunlight. Nitroacetone slowly hydrolyzes with water.
Nitro acetone has a melting point between 46-50 degC. When care is taken to obtain the pure product, the melting point tends to be close to 49 degC.
Nitroacetone might be useful for preparing 4-methyl-5-nitro-triazole, by condensing it with sodium azide in the presence of concentrated NaOH. This would be a Michael addition reaction.