NL1005223C2 - Process for the preparation of hexaazaiso-turf sitanone derivatives and an alpha-polymorphic form of a hexaaza-furfur-seated sitan derivative. - Google Patents

Description

- 1 - METHOD FOR PREPARING HEXAAZAI

SOWURTZITA DERIVATIVES AND AN A-POLYMORFE

FORM OF A HEXAAZAISOWURTZITAENERIVATE

The present invention relates to a new process for the preparation of tetraacetyldibenzyl-hexaazaiosurtsurate, to a new process for the preparation of hexanitrohexaaza-saisurturtanane and to a new polymorphic form, which is called a, of hexanitrohexaaza-sowurtisane.

The invention is in the field of gunpowder, rocket fuels and explosives that are very commonly used, particularly in the weapons industry.

In recent years, a large number of publications have been about 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo [5.5.0. O5.9. O3,13] dodecane, also called hexanitrohexaazaisowurtzitan, appeared.

These publications describe the physical and chemical properties and detonation behavior of this compound and / or various polymorphic forms and their use in explosive compositions, rocket fuels or gunpowder for weapons.

For example, reference may be made to F. Foltz who, in Popellants, Explosives, Pyrotechnics 19, 63-69 25 (1994), studied the thermal stability of the e-polymorph in a poly (urethane ester) and that in Propellants, Explosives, Pyrotechnics 19, 19-25 (1994) studied the thermal stability of the four polymorphic forms, which are called οι-, β-, 7- and e-polymorph.

However, the data on the synthesis of this compound are very scarce, inaccurate and insufficient to enable the person skilled in the art, even with his general knowledge, to perform this synthesis.

Although the authors of the above publications sometimes state that the compound is derived from hexabenzyl-hexaazawurtzitane, they never describe how this was done.

The most accurate data on the synthesis can be found in Japanese Patent Application J 06321962A which relates to the preparation of hexakis (trimethylsilyl-ethylcarbamyl) hexaaza-bis-succitane from hexabenzyl-hexa-15-bisa-bis-se-sitanes.

In that article it is stated that hexanitro-hexaazaiso-succitan can be obtained from this silylated intermediate by reacting it first with nitrous acid and then reacting with nitric acid, but no example of such a reaction is given and no details are given. about the conditions of the operation (temperature, acid concentration, environment, etc.).

Arnold T. Nielsen, during a convention in 25 Long Beach, California, organized by the American Defense Preparedness Association and held at the Queen Mary hotel from October 27-29, 1986, synthesized 4,10-dibenzyl- 2,6,8,12-tetraacetyl-2,4,6,8,10,12-hexaazate tetracyclo [5.5.0. O5.9, O3.11] dodecane, also known as tetraacetyl dibenzylhexaaza azurtsurate, disclosed by the reaction at 60 ° C of hexabenzylhexaaza azurazurtsurate with acetic anhydride in the presence of hydrogen and Pd / C as catalyst. The yield is not high (25%). The author has furthermore indicated that he has investigated numerous reaction conditions of the nitration of tetraacetyldi-benzylhexaaza azurazone with the aim of obtaining hexanitrohexaaza aza-azo-azo-azo-azo-1-azo-1-azo-1-azo-1-azo-1-azo-1-azo

In spite of this prejudice, the reaction conditions have been found which, on the one hand, enable hexanitro-hexaaza-azurazone to be obtained in a good yield from tetraacetyldibenzylhexaaza-azurazurotanone and, on the other hand, make it possible to substantially improve the yield of the preparation of tetraacetyldibenzylhexaaza-azurazuroyturanium from hexabenzyl-hexaaza-azurazuroturanium.

The present invention thus relates in the first place to a new process for the preparation of tetraacetyl dibenzyl hexaaza azurazurtsurotane by reductive acetylation of hexabenzyl hexaaza azurazurtsuroo sitane, more precisely by the reaction of hexabenzyl hexaaza azurosurtsurite sit with acetic anhydride in the presence of hydrogen and a catalyst based on palladium.

Unexpectedly, the yield of this synthesis was found to be increased considerably, to 80% instead of 25%, when, together with the palladium-based and acetic anhydride-based catalyst, a particular solvent, dimethylformamide (DMF), and a bromine-containing co- uses a catalyst selected from the group consisting of brominated aromatic derivatives and hydrogen bromide; their use in hydrogenolysis reactions is not known in the art.

The present invention therefore provides a process for the preparation of tetraacetyl dibenzylhexa-aza-zurosaturate by reacting hexabenzylhexaaza-azurosurvurate with acetic anhydride in the presence of hydrogen and a catalyst based on palladium, characterized in that the reaction is carried out in a dimethylformamide environment in the presence of of a brominated cocatalyst selected from the group consisting of brominated aromatic derivatives and hydrogen bromide, and that after the reaction of hexabenzylhexaaza aza aza aza aza aza aza aza aza aza aza aza azuraza is isolated by first dissolving 1 0 05 2 2 2 - 4 - by heating the reaction medium after adding acetic acid and then filtering the reaction medium and concentrating the filtrate.

"Brominated aromatic derivative" refers to a derivative in which at least one bromine atom is directly bonded to the aromatic ring.

The brominated cocatalyst is preferably a brominated benzene derivative. Mono-, di- and tribromobenzenes are particularly preferred, in particular bromobenzene.

Comparison tests carried out with solvents other than DMF or in the absence of the co-catalyst and / or in the presence of a co-catalyst other than the above show that the choice of the experimental parameters according to the invention is not arbitrary and that only this choice produces the sought-after and found technical effect.

Palladium-based catalyst is preferably used as a palladium-based catalyst, for example on carbon as a carrier.

Furthermore, the palladium content, expressed as the weight of the metal with respect to the weight of hexabenzyl hexaaza azurau, is preferably between 0.05 and 0.2%, and in particular between 0.1 and 0.2%.

Higher palladium levels can be used, for example 0.3 to 0.5%, without affecting the yield of the reaction, but this is economically disadvantageous.

Preferably, a molar excess of acetic anhydride with respect to hexabenzyl hexaazaiso-siturethane is used.

Furthermore, the molar ratio between the brominated cocatalyst and hexabenzyl hexaaza azurau sitane is preferably between 0.015 and 0.5, more preferably between 0.025 and 0.25 and most preferably between 0.03 and 0.10. It was unexpectedly found that the improvement in yield at J 0 052 2? The latter conditions are optimal and that this improvement becomes less as the said ratio increases.

The duration of the reaction is usually several hours and depends in particular on the temperature and the hydrogen pressure.

Regarding the temperature: preferably the reaction is started at a temperature near room temperature, for example a temperature between 0 and 30 ° C, and more preferably between 15 and 2%, after which the temperature is raised to a temperature between 45 and 75 ° C, and preferably between 50 and 60 ° C, after which this temperature is maintained.

The hydrogen must be well dispersed in the environment and therefore a system is preferably used which ensures a fine distribution and an efficient stirring system.

The hydrogen pressure may, for example, be between. 10s Pa and .5 IQ5 Pa (1 to .5 bar). A hydrogen pressure between 10s Pa and 2.10s Pa, or even between 10s Pa and 1.5.10s Pa is excellent.

In order to isolate the tetraacetyldibenzyl-hexaazaiso-le-sitane formed after the reaction, it is completely dissolved in the reaction medium by heating after addition of acetic acid to the environment, and then the medium is filtered to separate the catalyst from the filtrate.

The desired product is then recovered in the usual manner by concentrating the filtrate.

The present invention also relates to a process for the preparation of hexanitrohexaazaiso-wurtzitane, characterized in that in a first step the tetraacetyldibenzylhexaazazo-wurtzitane obtained as above according to the invention is nitrosated with the aid of a nitrosating agent and subsequently in a second step nitrates the product obtained in the first step with a nitrating agent. Nitrosating and nitrating agents are known to those skilled in the art. Nitroxides and nitrosonium salts may be mentioned as examples of nitrosating agents, and nitric acid, N 2 O 5, mixtures of sulfuric acid and nitric acid and of acetic acid and nitric acid and nitronium salts may be mentioned as examples of nitrating agents.

Preferably, the tetraacetyl dibenzyl hexaazaiso-sitane is first reacted with nitrogen tetroxide. In this case, the nitrogen tetroxide, the nitrosating agent, can also serve as a solvent.

The nitrosation and / or nitration is generally carried out in an organic solvent environment, preferably a chlorinated solvent such as chloroform, 1,2-dichloroethane; methylene chloride is particularly preferred.

If the nitration of the product obtained after the first step is carried out with concentrated nitric acid or a mixture of sulfuric acid and nitric acid, it is sufficient to add concentrated mixture of sulfuric acid and nitric acid or the sulphosalpetic acid mixture to the reaction medium after the first step.

The temperature of the nitrosation is preferably between 10 and 35 ° C, for example room temperature, and the temperature of the nitration is preferably between 45 and 850 ° C.

The nitrosating agent and the nitrating agent are preferably used in an excess with respect to tetraacetyl-dibenzylhexaazaiso-lean siturane.

After isolating the sought-after product in the usual way, it is unexpectedly apparent, in particular by X-ray Fourier transform infrared analysis, that the hexanitrohexaaza azaisa leopherane obtained in this way is in the α-form as described in the literature, in particular by F01TZ in the above-mentioned articles.

The present invention therefore also relates to the alpha-polymorphic form of hexanitrohexaazaiso-wurtzitane, the synthesis of which was not known to those skilled in the art and was not suggested by the prior art either.

1 0052 23 - 7 -

The following non-limiting examples serve to illustrate the invention and the advantages to be gained therewith.

Examples 1 to 24: Synthesis of tetraacetyl diben-5-zylhexaaza azurau sitane

Example 1:

A 250-ml double-walled reactor equipped with a magnetic stirrer, a water cooler and a lead-in tube equipped with a glass filter for introducing hydrogen was filled with -67 ml DMF, 17 ml acetic anhydride at ambient temperature (15-20 ° C) , 0.23 g (1.46 mmol) bromobenzene, 20.8 g (29.4 mmol) hexabenzyl-hexaazaisowu, rtzitane and 1.15 g palladium hydroxide on carbon (moisture content: 50%, palladium content in dry matter: 5%) .

After flushing the set-up with an inert gas, introducing hydrogen into the reaction medium and maintaining the hydrogen pressure in the reactor between 1.13 and 1.25 105 Pa., The reaction medium was at 55 ° C in 3 hours from ambient temperature C, after which this temperature was maintained for 2 hours.

The hydrogen supply was stopped, 158 ml of acetic acid were added to the reaction medium, which was subsequently brought to a temperature between 80 and 90 ° C.

The reaction medium was filtered to separate the catalyst. The filtrate was concentrated at 60-70 ° C under a reduced pressure of 2.5 to 5.103 Pa (about 20 to 40 mmHg).

After cooling to ambient temperature, the residue was taken up in 100 ml of acetone. The resulting tetraacetyl dibenzyl hexaazaiso-situtenane, which had precipitated, was filtered off and rinsed with 50 ml of acetone.

After drying for 24 hours at 30 ° C under a reduced pressure of 5,103 Pa (approximately 40 mmHg), 12.1 g (yield 80%) of tetraacetyl dibenzyl hexaaza bisautur sitane, identified by comparison with mass spectrometry, infrared and 60 MHz proton NMR comparison spectra.

Examples 2 and 3: Influence of the hydrogen pressure.

For these two examples, Example 1 was repeated exactly 5, except that the hydrogen pressure was 2,105 Pa (2 bar) in Example 2 and 3.6,105 Pa (3.6 bar) in Example 3.

The isolated yield of tetraacetyl dibenzyl hexaazaiso-leur sitane was 81.4% in Example 2 and 75% in Example 3.

Examples 4 to 11: Influence of the amount of bromobenzene.

For these examples, Example 1 was repeated exactly, but with different amounts of bromobenzene, which were such that the molar ratio between bromo-15 benzene and hexabenzylhexaaza azurau siturane in Examples 4 to 11 and 0 (no bromobenzene), 0.03, 0.10 , 0.18, 0.33, 0.5, 0.7 and 1.

The yield of isolated tetraacetyl dibenzyl hexaazaiso-leur sitane was 15%, 79%, 79%, 77%, 73%, 70%, 50% and 45%, respectively.

Examples 12 to 16: Influence of the amount of catalyst Pd (0H) 2 / C.

For these examples, Example 1 was repeated, but with different amounts of catalyst Pd (OH) 2 / C, namely 0 (no catalyst), 0.41 g, 0.83 g, 2.1 g and 4.2 g in respectively Examples 12 to 16 instead of 1.15 g in Example 1.

The yield of isolated tetraacetyl dibenzyl hexaazaiso-leur sitane was 0%, 45%, 82%, 80% 30 and 78%, respectively.

Example 17: Influence of the increase in temperature.

1 005228 - 9 -

For this example, Example 1 was repeated, but the manner in which the temperature of the reaction medium was raised was changed.

The reaction medium was first brought to 60 ° C in 2 hours from ambient temperature, the temperature was lowered to 40 ° C in 0.5 hour and then the temperature was raised to 55 ° C in 0.5 hour. This temperature was then maintained for 2 hours.

The yield of tetraacetyl dibenzyl-10-hexaaza-aisuphrtane isolated was 83.5%.

Examples 18 to 21: Influence of the nature of the solvent.

For these four examples, Example 1 was repeated exactly, but instead of DMF, in Example 18, chloroform, in Example 19, 1,2-dichloroethane, in Example 20, a 50/50 v / v mixture of DMF and chloroform and in Example 21 uses a 50/50 v / v mixture of DMF and 1,2-dichloroethane.

In all of these four Examples 18 to 21, the yield of the product sought was zero.

Examples 22 and 23: Influence of the nature of the co-catalyst

For these two examples, Example 1 was repeated exactly, but instead of bromobenzene, the same molar amount of hydrogen bromide and

Example 23 uses the same molar amount of N-bromosuccinimide.

The yield was 81% in Example 22 and nil in Example 23.

Example 24: Synthesis of hexanitrohexaazaiso-lean sitane by nitrosation with a nitrosonium salt and then nitration with a nitronium salt.

A 150 ml reactor was charged with a 63 g of sulfolane, 0.28 g of water and 6.3 g (5.4 x 12 mol) of nitrosonium fluoroborate. After stirring at ambient temperature for 0.5 hour, 1 g (2.10-4 mole) of tetraacetyl dibenzyl hexaaza azurau tuerto sitane obtained according to Example 1 was added.

After stirring for 1 hour at a temperature between 17 and 20 ° C, the reaction medium gradually became 55 ° C in 0.7 hour

heated, after which this temperature was maintained for 1 hour. The mixture was then cooled to 17 ° C and 5.16 g (3.8 · 10 · 2 mol) of nitronium fluoroborate were added. The temperature was gradually increased to 55 ° C in 1 hour and this temperature was maintained for 1 hour. The mixture was then cooled to 17 ° C, after which 50 ml of water was added in portions while the temperature was kept below 20 ° C. The reaction mixture was poured into a 10 liter beaker, after which 5 liters of water were added gradually with stirring. After standing for 12 hours at 5 ° C, the precipitate formed was filtered, and the precipitate was dried under reduced pressure in the presence of phosphoric anhydride. 0.73 g of hexanitrohexaazaisowurtzitane (yield 86%) was obtained, a white solid identified by 20 200 MHz proton NMR in dimethyl sulfoxide (DMSO), carbon NMR under the same conditions, IR, elemental analysis and crystallographic X-ray examination.

The melting point is near 170 ° C and the purity was estimated at more than 95%.

The density is 1.95 g / cm 3 according to a gaspynomer determination and 1.97 g / cm 3 according to the crystallographic data obtained with X-ray analysis.

Crystallographic examination of a single crystal with X-rays shows that the compound crystallizes with about 25 mol% water and that it has an orthorombic crystal structure of the Pbca space group with the following lattice constants: a = 0.546 A, b = 13.232 A, c = 23.634 A and Z = 8.

Furthermore, the Fourier transform infrared spectrum of a 1% dispersion in KBr shows between 700 and 1200 cm -1 peaks characteristic of the α-polymorphic form with reference to the above-mentioned publication of 1 0 0522 3 - 11 -

Foltz, Table 1 on biz. 66. The peaks characteristic of the ε, β and 7 form were not observed.

The hexanitrohexaazaiso-siturane obtained thus occurs in the α-polymorphic form.

Example 25: Synthesis of hexanitrohexaazaiso-siturone by nitration with nitrogen tetroxide and then nitration with concentrated nitric acid.

In a 1-liter double-walled reactor equipped with a mechanical stirrer and a temperature meter, 313 g (3.37 mol) of liquid N 2 O 4 was charged at 0 ° C.

At a temperature between 0 and 5 ° C, 133 g (0.259 mol) of tetraacetyl dibenzylhexaaza azaisa turate sitane obtained according to Example 1 were added.

The temperature of the reaction medium was allowed to rise from 15-16 ° C (N 2 O 4 reflux) and the reaction medium was then left under stirring under N 2 O 4 reflux for 20 hours.

After cooling the mixture to 0 ° C, at a temperature between 0 and 8 ° C, 667 ml of a 20/80 v / v mixture of sulfuric acid and nitric acid was added, which was. corresponds to the addition of 12.8 moles of nitric acid.

The reaction mixture was then gradually heated to remove the excess N 2 O 4 by distillation and then allowed to stand. after reaching a temperature between 73 and 75 ° C, the reaction mixture is stirred for 4 hours.

After cooling to 40 ° C, the mixture was poured onto 2 liters of a mixture of water and ice. A solid separated and was collected by filtration and washed on the filter with warm water (40 ° C) until the pH of the aqueous wash was neutral.

After drying, 104 g (97% yield) of hexanitrohexaazaiso-situtenane was obtained, which was identified in the manner described in Example 25 and whose purity was estimated to be more than 95% according to the analyzes carried out. It exhibits the same crystal structure as the product obtained according to Example 25, in particular that it occurs in the α-polymorphic form.

1 0 052 2 3

Claims (8)

1. A process for preparing tetraacetyldi-benzylhexaaza-aisurtsuentane by reacting hexabenzylhexaaza-aisurtsuptisane with acetic anhydride in the presence of hydrogen and a palladium-based catalyst, characterized in that the reaction is carried out in a dimethylformamide environment in the presence of a brominated copolymer. catalyst selected from the group consisting of brominated aromatic derivatives and hydrogen bromide, and that after the reaction of hexabenzylhexaaza azurau seated sitting with acetic anhydride, the tetraacetyl dibenzyl hexaaza azurau seated sittingane is isolated by first dissolving by heating the reaction medium after adding acetic acid and then filter the reaction medium and concentrate the filtrate. Process according to Claim 1, characterized in that the catalyst is palladium hydroxide based on palladium. 3. A method according to claim 2, characterized in that the palladium content is between 0.1 and 0.2% by weight, based on hexabenzyl hexaazaiso-siturate. Process according to one of the preceding claims, characterized in that the brominated cocatalyst is a brominated benzene derivative. Process according to one of the preceding claims, characterized in that the molar ratio between bromine-containing cocatalyst and hexabenzyl hexaazaiso-siturethane is between 0.03 and 0.1. 1 0 05223 - 14 - 6. A method according to any one of the preceding claims, characterized in that the temperature of the reaction medium is raised from a temperature between 0 and 30 ° C to a temperature between 45 and 75 ° C and this latter temperature is then maintained. 7. Process for the preparation of hexanitro-hexaaza-bis-succitan, characterized in that in a first step the tetraacetyl-dibenzylhexaaza-bis-bis-succitane obtained in accordance with one of claims 1 to 6 is nitrated and then the product of the first step is nitrated in a second step. 8. α-polymorphic form of hexanitrohexaazaisowurtanone. o-o-o-o 1 0 052 2 3