BE1017609A4 - EPSILON POLYMERIC FORM OF ISOWURTZITANE DERIVATIVE AND PROCESS FOR SYNTHESIS. - Google Patents

Abstract

The invention relates to a new polymorphic form, called epsilon, of hexanitrohexaazaisowurtzitane, as well as to the synthesis of this form. According to a first method, hexanitrohexaazaisowurtzitane of any polymorphic form is mixed in a premix comprising 20% to 40% by weight of a glycidyl polyazide and 60% to 80% by weight of at least one trinitrate of a triol. monomer having 3 to 12 carbon atoms, then carries out at least one thermal heating cycle of the mixture at a temperature between 40 ° C and 60 ° C and at a temperature between 10 ° C and 30 ° C, then eliminated the constituents of the premix by washing with an organic solvent. According to a second process, a saturated hexanitrohexaazaisowurtzitane solution of any polymorphic form is prepared in an acetone / toluene mixture, seeded with a few hexanitrohexaazaisowurtzitane crystals of epsilon form, and then the solution is concentrated by evaporation of the acetone. Hexanitrohexaazaisowurtzitane, especially the particularly dense epsilon form, is useful as an explosive or oxidizing charge in pyrotechnic compositions.

Description

Epsilon polymorphic form of an isowurtzitane derivative and methods of synthesis

The present invention relates to a new polymorphic form, called epsilon, of hexanitrohexaa-zaisowurtzitane, as well as to two methods of synthesizing this new polymorphic form.

The invention lies in the field of powders, propellants, and explosives, very commonly used, especially in the armament industries.

In recent years there have been numerous publications on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo (5.5.0.O5 / 9.O3 / H) dodé-cane also called hexanitrohexaazaisovmrtzitane.

These publications describe the physical, chemical and detonation properties of this compound and / or various polymorphic forms, as well as its use in explosive compositions, propellants or gun powders.

For example, F. FOLTZ, which, in Propellants, Explosives, Pyrotechnies 19, 63-69 (1994), studies the thermal stability of the epsilon polymorph in a poly (urethane-ester), and which, in Propellants, Explosives Pyrotechnies 19, 19-25 (1994) studies the thermal stability of the four polymorphic forms called alpha, beta, gamma and epsilon.

However, the information concerning its synthesis is very rare, inaccurate and insufficient for the skilled person, even with his general knowledge, to achieve it.

Although the authors of the aforementioned publications sometimes mention that the compound was obtained from hexabenzylhexaazaisowurtzitane, they never describe how.

The most accurate information concerning the synthesis is found in Japanese Patent Application No. 06321962 A relating to the synthesis of hexakis (trimethylsilylethylcarbamyl) hexaazaisowurtzitane from hexabenzylhexaazaisowurtzitane.

It is mentioned that hexanitro-hexaazaisowurtzitane can be obtained from this silylated intermediate by first reacting it with nitrous acid and then with nitric acid, but no example of such a reaction can be obtained. is described, and no details concerning the operating conditions (temperature, concentration of acids, medium, etc.) are indicated.

Arnold T. NIELSEN, at the Long Beach Convention (California, USA) organized by the American Defense Preparedness Association and held at the Queen Mary Hotel on October 27-29, 1986, disclosed the synthesis of 4,10-dibenzyl-2 , 6,8,12-tetraacetyl-2,4,6,8,10,12-hexaa-zatetracyclo (5.5.0.O5 / 9.O3> 11) dodecane, also called tetraacetyldibenzylhexaazaisowurtzitane, by reaction, at 60 ° C during 6h, hexabenzylhexaazaisowurtzitane with acetic anhydride, in the presence of hydrogen and Pd / C as catalyst. The yield is 25%.

The author also states that he has studied numerous conditions for the nitration of tetraacetyldibenzylhexaazaisowurtzitane in order to obtain hexanitrohexaazaisowurtzitane, but this compound could never be obtained.

In spite of this prejudice, operating conditions have been found permitting obtaining, with an excellent yield, hexanitrohexaazaisowurtzitane from tetraacetyldibenzylhexaazaisowurtzitane. The hexanitrohexaazaisowurtzitane thus obtained is in the polymorphic alpha form, with reference to the aforementioned FOLTZ publications. Its density is 1.97 g / cm3.

Now, according to these same FOLTZ publications, it is the epsilon polymorphic form which has the highest density, and which therefore seems to be of the greatest interest, especially for its use in pyrotechnic compositions.

If certain properties and characteristics of the epsilon form of hexanitrohexaazaisowurtzitane are known to those skilled in the art, the information included in the same state of the art, even supplemented by the general knowledge of those skilled in the art, does not allow this one to prepare and isolate it.

Those skilled in the art are therefore in search of a method making it possible to obtain this epsilon polymorphic form.

The present invention solves this problem.

It firstly relates to the epsilon polymorphic form of hexanitrohexaazaisowurtzitane. whose synthesis was not known to those skilled in the art, nor suggested by the state of the art.

It also relates to two methods of synthesis of this epsilon polymorphic form, whose density is 2.04 g / cm3.

This high density makes this polymorphic form epsilon particularly interesting as an explosive or oxidizing charge in the pyrotechnic compositions.

According to the invention, a first method for synthesizing the epsilon polymorphic form consists in firstly mixing hexanitrohexaazaisowurtzitane of any polymorphic form, for example alpha, in a premix comprising: 20% to 40% by weight of a glycidyl polyazide corresponding to the general formula

wherein x is an integer such that 10 ^ x ^ 60 and R is a group - (- CH2 -) - h ~ N3 or -CH2 "CHN3-CH2N3 where n is an integer such that 1 <n ^ 5 60% to 80% by weight of at least one trinitrate of a monomeric triol having 3 to 12 carbon atoms, then to then carry out at least one, preferably several, and more preferably at least five, thermal cycle of heating the mixture at a temperature of between 40 ° C. and 60 ° C. and then at a temperature of between 10 ° C. and 30 ° C., and finally removing the constituents of the premix by washing with an organic solvent.

When hexanitrohexaazaisowurtzitane is mixed with the premix, a suspension of hexanitrohexaazaisowurtzitane is obtained in the premix, but a small portion is nevertheless dissolved.

Preferably, R is -CH2N3 and x is such that 20 <x <40.

Also preferably, the premix comprises 60% to 80% by weight of a mixture of trimethylolethane trinitrate and 1,2,4-butanetriol.

According to a preferred variant, this premix consists of 27.5% by weight of glycidyl polyazide, 35% by weight of trimethylolethane trinitrate, 35% by weight of 1,2,4-butanetriol trinitrate, 1,2 5% by weight of 2-nitrodiphenylamine and 1.25% by weight of N-methylparanitroaniline.

In general, according to this first method, the mass ratio between the premix and the hexanitrohexaazaisowurtzitane to be recrystallized, respectively, is between 10 and 100.

According to a preferred variant, at least 5 successive thermal cycles of 2 h at 50 ° C. and 2 h at 20 ° C. are carried out.

On the other hand, among the premix washing solvents which are suitable, mention may be made of chlorinated solvents, especially methylene chloride, which is particularly preferred.

The second method for synthesizing the epsilon polymorphic form of hexanitrohexaazaisowurtzitane consists in producing a saturated solution of hexanitrohexaazaisowurtzitane of any polymorphic form, for example alpha, in an acetone / toluene mixture, and then inoculating this saturated solution with a few crystals of hexanitrohexaazaisowurtzitane of polymorphic form epsilon, then finally to concentrate the solution by evaporation of acetone.

In general, the volume ratio acetone / toluene respectively, is between 10/90 and 50/50, more preferably between 15/85 and 30/70, for example 20/80 or 25/75.

According to a preferred variant, the amount of seed represents between 0.1% and 1% by weight of the amount of hexanitrohexaazaisowurtzitane of any polymorphic form to be recrystallized.

Unexpectedly, it has been found that a product of higher purity, that is free of other polymorphic forms of hexanitrohexaazaisowurtzitane, is obtained when, during the operation of concentration of the solution by evaporation. acetone, the temperature does not exceed 30 ° C, that is to say when it is less than or equal to 30 ° C, for example between 10 ° C and 30 ° C, preferably between 20 ° C and 30 ° C.

According to another preferred variant, to produce the saturated solution of hexanitrohexaazaisowurtzitane in the acetone / toluene mixture, the process is simplified when a saturated solution of hexanitrohexaazaisowurtzitane is first made in acetone and toluene is then added. .

If the saturated solution contains hexanitro-hexaazaisowurtzitane in suspension, it is preferable to remove this suspension, for example by filtration, before seeding, so as not to pollute the final product obtained.

This second method is much simpler to implement, more economical and more easily extrapolable at the industrial stage than the first. If it requires the prior provision, when implemented for the first time, a small amount of the desired product obtained by another method, the very low proportion of seed required in relation to the product to be recrystallized makes then the perfectly autonomous process.

The following nonlimiting examples illustrate the invention and the advantages it provides.

Example 1 Synthesis of tetraacetyldibenzylhexazis-isowurtzitane

In a 250 ml jacketed reactor equipped with a magnetic stirrer, a water cooler and an introduction rod equipped with a sinter for introducing hydrogen, is introduced at room temperature ( 15-20 ° C), 67 ml of dimethylformamide (DMF), 17 ml of acetic anhydride, 0.23 g (1.46 mmol) of bromotoenzene, 20.8 g (29.4 mmol) of hexabenzylhexaazaisowurtzitane and 1 15 g of palladium hydroxide on charcoal (moisture: 50%, palladium content in the dry matter: 5%). After purging the apparatus with an inert gas, and while introducing hydrogen into the medium and maintaining its pressure in the reactor between 1.10 10 Pa and 1.25 × 105 Pa, the reaction medium is brought to ambient temperature. up to 55 ° C in 3h, then this temperature is maintained for 2h.

The introduction of hydrogen is stopped, then 158 ml of acetic acid is introduced into the medium which is then carried at a temperature of between 80 ° C. and 90 ° C.

This medium is filtered to separate the catalyst, and the filtrate is concentrated to 600 ° C.-70 ° C. under a reduced pressure of 2.5 × 10 3 Pa to 5 × 10 Pa (about 20 mm to 40 mm Hg).

After returning to ambient temperature, the residue is taken up in 100 ml of acetone. The tetraacetyldibenzyl-hexaazaisowurtzitane obtained, which precipitated, is filtered and rinsed with 50 ml of acetone.

After drying for 24 hours at 30 ° C. under a reduced pressure of 103 Pa (approximately 40 mmHg), 12.1 g (80% yield) of tetraacetyldibenzylhexaaza-isowurtzitane, identified by conformity with reference spectra by mass spectrometry, are obtained. infrared and proton NMR at 60 MHz.

Example 2 Synthesis of Hexanitrohexaazaisowurtzitane of Alpha Polymorph Form

In a 1-liter jacketed reactor equipped with mechanical stirring and a temperature probe, 313 g (3.37 mol) of liquid N 2 O 4 are introduced at 0 ° C.

133 g (0.259 mol) of tetraacetyldibenzylhexaazaisowurtzitane obtained according to Example 1 are added between 0 ° C. and 5 ° C.

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

After having cooled the medium to 0 ° C., 667 ml of a tallow / tallow mixture, respectively 20/80 by volume, are added between 0 ° C. and 8 ° C., which corresponds to the addition of 12.8 mol. 'nitric acid.

The medium is then gradually heated so as to eliminate the excess of N 2 O 4 by distillation, then, when the temperature of the medium reaches 73-75 ° C., the medium is left stirring for 4 h.

After cooling to 40 ° C, the medium is poured into 2 1 of a water-ice mixture. A decant solid which is recovered by filtration and washing with hot water (40 ° C) on filter until neutral pH washing water.

After drying, 104 g of hexanitro-hexaazaisowurtzitane (97% yield) white solid identified by proton NMR at 200 MHz in dimethyl sulfoxide (DMSO) are obtained by carbon NMR under the same conditions, by IR, by analysis. elemental and by X-ray crystallographic study.

Its melting point is close to 170 ° C. and its purity can be estimated to be greater than 95%.

Its density is 1.97 g / cm 3 based on X-ray crystallographic data.

The crystallographic study of a single crystal by X-rays shows that this compound crystallizes with about 25 mol% of water and that it has an orthorhombic crystalline structure of Pbca space group having the following mesh parameters: a = 9.546 , b = 13.232, c = 23.634 and Z = 8.

Moreover, the Fourier transform IR spectrum of a 1% dispersion in KBr has, between 700 cm -1 and 1200 cm -1, the characteristic peaks of the alpha polymorphic form, with reference to the aforementioned FOLTZ publication. Table 1 on page 66. The characteristic peaks of the epsilon, beta and gamma forms are not observed.

The hexanitrohexaazaisowurtzitane obtained is therefore in the alpha polymorphic form.

Example 3 Synthesis of hexanitrohexaazaisowurtzitane of polymorphic form epsilon. Mixing method

After having suspended, with partial dissolution, at room temperature close to 20 ° C., 0.5 g of hexanitrohexaazaisowurtzitane obtained according to Example 2 in 15 g of a premix consisting of: 27.5% by weight of the polyazide of glycidyl (PAG) of formula

in which x is an integer such that 20 ^ x ^ 40 marketed by SNPE under the reference PAG-diol 1800 and whose number-average molecular weight is close to 1800, -35% by weight of trimethylolethane trinitrate, 35% by weight of 1,2,4-butanetriol trinitrate, 1.25% by weight of 2-nitrodiphenylamine, 1.25% by weight of N-methylparanitroaniline, six successive thermal cycles of 2 h are carried out at 50.degree. then 2h at 20 ° C. Each cycle therefore consists of a heating period of the mixture of 20 ° C to 50 ° C, a period of maintaining the temperature 2h at 50 ° C, a cooling period of the mixture of 50 ° C to 20 ° C, and a period of maintaining the temperature 2h at 20 ° C.

The constituents of the premix are then completely removed by washing with methylene chloride on a filter.

0.47 g of hexanitrohexaazaisowurtzi-tane, identified as in Example 2, is collected.

Its density at 20 ° C is 2.04 g / cm 3 based on X-ray crystallographic data.

The crystallographic study of an X-ray single crystal shows that the product has a monoclinic space group crystalline structure whose mesh parameters are: a = 8,864, b = 12,581, c = 13,388 and Z = 4 .

Moreover, the Fourier transform IR spectrum of a 1% dispersion in KBr has, between 7 00 cm-1 and 1200 cm-1, the characteristic peaks of the epsilon polymorphic form, with reference to the aforementioned FOLTZ publication. , Table 1, page 66. The characteristic peaks of the alpha, beta and gamma forms are not observed.

The hexanitrohexaazaisowurtzitane obtained is thus in the polymorphic form epsilon.

Examples 4 and 5: Synthesis of hexanitrohexazazisowurtzitane of polymorphic form epsilon. Seeding method

Example 4

10 g of hexanitrohexaazaisowurtzitane obtained according to Example 2 are mixed at room temperature close to 20 ° C. with 20 ml of acetone. A saturated solution is thus obtained in which a small portion of the starting hexanitrohexaazaisowurtzitane remains in suspension.

80 ml of toluene are added, which makes it possible to obtain a saturated solution of hexanitrohexaazaisowurtzitane in a 20/80 mixture of acetone / toluene volumes respectively in which a small portion of the starting hexanitrohexaazaisowurtzitane remains in suspension.

This suspension is filtered and the filtrate is collected, ie the saturated solution, which is then seeded with a few crystals of hexanitrohexaazaisowurtzitane of polymorphic epsilon form obtained according to Example 3.

The mixture is then concentrated at 25 ° C. under a partial vacuum of 2.5 × 10 3 Pa 3 (about 20-40 mm Hg) until all of the acetone is removed.

A white solid (9 g) precipitates during this concentration operation, which is recovered by filtration.

This white solid, identified and analyzed as described for Example 3, which has all the characteristics, in particular physical and spectral, of the product obtained for Example 3, is hexanitrohexaazaisowurtzitane of polymorphic form epsilon.

Example 5

Example 4 was repeated, but with 0.5 kg of hexanitrohexaazaisowurtzitane obtained according to Example 2, 11 of acetone and 4 l of toluene. The quantity of seed is 2.5 g, ie 0.5% by weight of the amount of hexanitrohexaazaisowurtzitane to be recrystallized.

455 g of hexanitrohexaazaisowurtzitane of polymorphic form epsilon were obtained, identified and analyzed as in Examples 3 and 4.

Claims (10)

1. Epsilon polymorphic form of hexanitrohexaazaisowurtzitane. 2. Process for the synthesis of the epsilon polymorphic form of hexanitrohexaazaisowurtzitane, characterized in that hexanitrohexaazaisowurtzitane of any polymorphic form is mixed in a premix comprising: 20% to 40% by weight of a glycidyl polyazide answering to the general formula

where x is an integer such that 10 ^ x ^ 60 and R is a group

or -CH2-CHN3-GH2N3 wherein n is an integer such that 1 ^ n ^ 5, - 60% to 80% by weight of at least one trinitrate of a monomeric triol having 3 to 12 carbon atoms, which is then carried out at least one thermal heating cycle of the mixture at a temperature between 40 ° C and 60 ° C and then at a temperature between 10 ° C and 30 ° C. and then removing the constituents of the premix by washing with an organic solvent. 3. Synthesis process according to claim 2, characterized in that R represents -CH2N3, in that x is such that 20 × x <40, and in that the premix comprises 60% to 80% by weight of a mixture of trimethylolethane trinitrate and 1,2,4-butanetriol trinitrate. 4. Synthesis process according to claim 3, characterized in that the premix consists of 27.5% by weight of glycidyl polyazide, 35% by weight of trimethylolethane trinitrate, 35% by weight of trinitrate of 1.2, 4-butanetriol, 1.25% by weight of 2-nitrodiphenylmine and 1.25% by weight of N-methylparanitroaniline. 5. The synthesis method according to claim 1, characterized in that the mass ratio between the premix and the hexanitrohexaazaisowurtzitane, respectively, is between 10 and 100, in that one carries out at least 5 successive thermal cycles from 2h to 50h. ° C and 2h to 20 ° C, and in that the washing solvent is methylene chloride. 6. Process for the synthesis of the epsilon polymorphic form of hexanitrohexaazaisowurtzitane, characterized in that a saturated solution of hexanitrohexaazaisowurtzitane of any polymorphic form is produced in an acetone / toluene mixture, in that this saturated solution is seeded with a few hexanitrohexaazaisowurtzitane crystals of polymorphic form epsilon, and then in that the solution is concentrated by evaporation of acetone. 7. Synthesis process according to claim 6, characterized in that the volume ratio acetone / toluene respectively, is between 10/90 and 50/50. 8. Synthesis process according to claim 6, characterized in that the amount of seed represents between 0.1% and 1% by weight of the amount of hexanitrohexaazaisowurtzitane of any polymorphic form. 9. Synthesis process according to claim 6, characterized in that during the operation of concentration of the solution by evaporation of acetone, the temperature does not exceed 30 ° C. 10. Synthesis process according to claim 6, characterized in that a saturated solution of hexanitrohexaazaisowurtzitane in acetone is first produced and toluene is then added.