DE4323776A1 - Novel Azidoalkylformale, their preparation and their use as plasticizers in solid pyrotechnic compositions - Google Patents

Abstract

The invention relates to new Azidoalkylformale of the general formula I, $ F1 in which: n is an integer with 1 <= n <= 3 AND R <SUB> 1 </ SUB> and R <SUB> 2 </ SUB>, the may be the same or different, H or CH <SUB> 3 </ SUB>, and their use as plasticizers in solid pyrotechnic compositions. The invention further relates to novel solid pyrotechnic compositions consisting of a plasticized and filled polymeric matrix, wherein the plasticizer comprises an azidoalkyl formal of general formula I and the filler contains at least one inorganic oxidizing agent or one organic nitro-explosive. The Azidoalkylformale of general formula I are relatively stable and not very sensitive and can be prepared by simple and inexpensive synthesis.

Description

The This invention relates to the field of energetic plasticizers for solid pyrotechnic compositions, explosives or propellants and in particular for solid propellants.

The Interest in the use of energetic plasticizers in such compositions as compared to use inert plasticizers, such as triacetin and dibutyl phthalate, is the Person skilled in the art. energetic Plasticizers allow in particular an increase the energy potential of corresponding compositions as well as in Case of solid propellants an increase in the burning rate and the specific impulse.

by virtue of the low production cost and its energy contribution is nitroglycerin used as plasticizer in propellants to a large extent. This connection is extremely dangerous and requires special precautions in handling. About that It also does not allow you to achieve higher burning speeds. Other nitric esters, such as 1,1,1-trimethylolethane trinitrate (TMETN) or 1,2,4-trihydroxybutane trinitrate (also known as butanetriol trinitrate or BTTN) or nitrated derivatives, such as bis (2,2-dinitropropylacetal) formally (BDNPAF), which are less sensitive than nitroglycerin also used, but at the expense of the properties goes as these compositions have a lower energy content than in the case of using nitroglycerin.

It There are also known other energetic plasticizers which however, have a relatively complex chemical structure, thereby their synthesis, starting from starting materials available in the chemical industry, requires numerous process steps and therefore very costly is.

US 4,440,687 describes the use of azidonitramino ethers as energetic plasticizers in solid propellant compositions. These plasticizers are made by reacting an alkali azide with nitramines, the synthesis of which requires multiple steps, including nitration, is expensive, expensive, and requires special precautions. In addition, the azidonitraminoethers obtained as crude products must still be purified by silica gel chromatography before use.

US 4 141 910 describes the use of 1,3-diazido-2-propylfluorodiethylformal as an energetic plasticizer in solid propellants. This Azidoalkylformal is prepared by reacting the chloromethyl ether of Fluordinitroethanol with 1,3-diazido-2-propanol. The synthesis of these two compounds from industrially available starting materials is tedious and expensive. In addition, the crude product obtained is not sufficiently pure for direct use, and therefore an additional purification step by column chromatography on alumina is required. The achievable on a laboratory scale when using these energetic plasticizers advantages are correspondingly in terms of manufacturing on an industrial scale considerable restrictions because of the prohibitive cost and complexity of the synthesis of these substances.

Of the Specialist was therefore faced with the task of new energetic Plasticizer for solid pyrotechnic compositions specify similar properties to those used previously have energetic plasticizer, but their synthesis is easy and cheap and at the same time in the chemical industry available raw materials.

The Task is solved according to the claim. The Subclaims relate to advantageous embodiments the inventive concept.

worin n eine ganze Zahl mit 1 ≤ n ≤ 3 und R₁ und R₂, die gleich oder verschieden sein können, H oder CH₃ bedeuten, und insbesondere Bis(2-azidoethyl)formal, in dessen Formel entsprechend n = 1 und R₁ und R₂ = H sind, deren Synthese einfach und billig ist und von Formaldehyd oder Acetaldehyd und

ausgeht, alle physikalischen, chemischen und Explosiveigenschaften aufweisen, die sie, und zwar ohne vorhergehende Reinigung des erhaltenen Syntheserohprodukts, zur Verwendung als energetische Plastifizierungsmittel in festen pyrotechnischen Zusammensetzungen geeignet machen. Die erfindungsgemäßen Azidoalkylformale erlauben ferner eine mit bekannten energetischen Plastifizierungsmitteln vergleichbare Erhöhung des Energiepotentials entsprechender Zusammensetzungen sowie, im Fall der festen Propergole, eine Erhöhung der Abbrandgeschwindigkeit und des spezifischen Impulses.The invention is based on the unexpected finding that new Azidoalkylformale the general formula I,

wherein n is an integer with 1 ≦ n ≦ 3 and R ₁ and R ₂ , which may be the same or different, are H or CH ₃ , and especially bis (2-azidoethyl) formal, in the formula of which n = 1 and R ₁ and R ₂ = H, the synthesis of which is simple and inexpensive and of formaldehyde or acetaldehyde and

have all the physical, chemical and explosive properties that make them suitable for use as energetic plasticizers in solid pyrotechnic compositions, without prior purification of the resulting crude synthesis product. The Azidoalkylformale invention also allow comparable with known energetic plasticizers increase the energy potential of corresponding compositions and, in the case of solid propellants, an increase in the burning rate and the specific pulse.

These findings are all the more surprising since the Azidoalkylformale of general formula I have no other energy-providing groups than the two azido groups, in contrast to known azido plasticizers for solid pyrotechnic compositions containing other energy-providing groups, such as C-NO ₂ , N-NO ₂ and -CF (NO _{2) 2,} included.

The Azidoalkylformale of the general formula I, and in particular bis (2-azidoethyl) formal, are relatively stable and have low sensitivity.

Your Educational heat is particularly advantageous, in particular the of bis (2-azidoethyl) formal which is +243 kJ / mol (58 kcal / mol).

in der n, R₁ und R₂ die obige Bedeutung besitzen und X ein Halogenatom bedeutet, vorzugsweise Chlor, hergestellt werden.The azidoalkylformals of the general formula I can be obtained by reacting a metal azide, preferably an alkali metal azide, such as sodium azide or potassium azide, with a bis (haloalkyl) formal of the general formula II,

in which n, R ₁ and R _{2 have} the above meaning and X represents a halogen atom, preferably chlorine, are prepared.

These Reaction of the introduction of an azido group is easy and becomes generally in a polar aprotic solvent medium such as dimethyl sulfoxide (DMSO) or dimethylformamide (DMF) made. The reaction temperature is generally in the range of 20 to 100 ° C and preferably in the range of 60 to 95 ° C. It is further preferably, the azide with respect to the bis (haloalkyl) formally the general formula II in excess.

in der X, n und R₁ die obige Bedeutung besitzen, in saurem Medium hergestellt werden können.The bis (haloalkyl) -formals of the general formula II are known compounds which are easily prepared by reacting formaldehyde, when R _{2 is} hydrogen, or acetaldehyde, when R _{2 is} methyl, with haloalkanols of the general formula III,

in which X, n and R _{1 have} the above meaning, can be prepared in acidic medium.

This reaction can be carried out, for example, under process conditions which are of DM Vinokurov in Izv. Vysshikh Uchebn. Zavedenii, Khim-i Khim. Tekhnol. 4, 988-91 (1961) , Chemical Abstracts: 57: 16378c.

Formaldehyde, Acetaldehyde and haloalkanols of the general formula III, in particular 2-chloroethanol, are commercial products that are light are accessible.

Obtained in this way in two stages by a simple and inexpensive process without additional purification from the chemical industry inexpensive and readily available starting materials such as formaldehyde and 2-chloroethanol directly as an energetic plasticizer in solid pyrotechnic compositions such as composite explosives and solid composite -Propergolen, dibasic Propergo len or dibasic composite propellants, usable product.

The The present invention accordingly also relates to the use the Azidoalkylformale of the general formula I, and in particular preferably bis (2-azidoethyl) formal, as plasticizer in solid pyrotechnic compositions, for example composite explosives and solid propellants, in particular dibasic composite propellants.

• – Unter einer "festen pyrotechnischen Zusammensetzung" wird eine Zusammensetzung verstanden, die zu Abbrennen, Deflagration oder Detonation befähigt ist und unter normalen Temperatur- und Druckverhältnissen (20°C und 10⁵ Pa) in festem Zustand vorliegt;
• – unter "Komposit-Sprengstoff" wird eine feste, in funktioneller Hinsicht detonierbare pyrotechnische Zusammensetzung verstanden, die im wesentlichen aus einem mit Füllstoff gefüllten und ggf. einen Weichmacher enthaltenden Polymermaterial besteht, wobei der Füllstoff pulverförmig ist und einen organischen Nitro-Sprengstoff enthält;
• – unter "zweibasigem Komposit-Propergol" wird eine feste, in funktioneller Hinsicht verbrennbare pyrotechnische Zusammen setzung verstanden, die im wesentlichen aus einer Polymermatrix besteht, die mit einem energetischen Plastifizierungsmittel weichgemacht ist und als Füllstoff ein anorganisches Oxidationsmittel und ggf. einen organische Nitro-Sprengstoff und/oder ein reduzierendes Metall enthält, wobei der Füllstoff pulverförmig ist;
• – unter "organischem Nitro-Sprengstoff" wird ein Sprengstoff verstanden, der unter den nitrierten aromatischen Sprengstoffen (die mindestens eine Gruppe C-NO₂ aufweisen, wobei das Kohlenstoffatom dieser Gruppe Teil des aromatischen Rings ist), den Salpetersäureester-Sprengstoffen (die mindestens eine Gruppe C-O-NO₂ aufweisen) und den Nitramin-Sprengstoffen (die mindestens eine Gruppe C-N-NO₂ aufweisen) ausgewählt ist.

In the context of the present invention, reference is made to the usual specialist terminology:

• - a "solid pyrotechnic composition" is understood to mean a composition which is capable of burning, deflagration or detonation and which is in solid state under normal temperature and pressure conditions (20 ° C and 10 ⁵ Pa);
• "Composite explosive" means a solid, functionally detonable, pyrotechnic composition consisting essentially of a filled and optionally plasticized polymeric material, the filler being powdered and containing an organic nitro explosive;
• - "dibasic composite propellant" is understood to mean a solid, functionally combustible pyrotechnic composition consisting essentially of a polymer matrix plasticized with an energetic plasticizer and an inorganic oxidant and optionally an organic nitro explosive as filler and / or a reducing metal, wherein the filler is powdery;
• - "organic nitro explosive" is understood to mean an explosive which is among the nitrated aromatic explosives (which have at least one group C-NO ₂ , wherein the carbon atom of this group is part of the aromatic ring), the nitric acid ester explosives (the at least one Group CO-NO ₂ ) and the nitramine explosives (having at least one group CN-NO ₂ ) is selected.

The The present invention further relates to novel solid pyrotechnic Compositions consisting essentially of one with a plasticizer plasticized polymer matrix containing a filler, wherein the filler is powdery and at least an inorganic oxidizing agent or an organic nitro explosive contains. They are characterized in that the Plasticizer Azidoalkylformal the general formula I is, preferably bis (2-azidoethyl) formal.

The Polymer matrix may be, for example, a nitrocellulose, a polyester, a polyether or a polyurethane.

If The polymer matrix is a polyurethane, it is generally by Reaction of a hydroxy terminated prepolymer prepared with a polyisocyanate.

Examples for prepolymers with hydroxy end groups are prepolymers with a framework based on a polyisobutene, polybutadiene, Polyethers, polyesters, polysiloxanes or polycaprolactones.

Examples for polyisocyanates are about isophorone diisocyanate (IPDI), Toluene diisocyanate (TDI), dicyclohexylmethylene diisocyanate (Hylène W), hexamethylene diisocyanate (HMDI) and biuret trihexane isocyanate (BTHI) and their mixtures.

If the polymer matrix is a polyester matrix, it generally becomes by reacting a prepolymer with terminal Carboxy groups, preferably a terminal polybutadiene Carboxy groups (PBCT) or a terminal polyester Carboxy groups, with a polyepoxide, for example a condensation product of epichlorohydrin with glycerin, or a polyaziridine, for example trimethylaziridinylphosphine oxide (MAPO).

The Polymer matrix may be generally inert or active, i. H. energizing Groups, such as azido groups, nitramino groups or fluoro-diethyl groups, contain.

The inorganic oxidizing agent is preferably ammonium perchlorate, Potassium perchlorate, ammonium nitrate and sodium nitrate, and mixtures selected from these compounds.

Of the organic nitro explosive is preferably under hexogen (RDX), Octogen (HMX), 5-oxo-3-nitro-1,2,4-triazole (ONTA), pentritol, triaminotrinitrobenzene (TATE) and nitroguanidine and mixtures of these compounds selected.

To a preferred variant contains the filler an inorganic oxidizer and an organic nitro explosive.

To another preferred embodiment the filler is a reducing metal, preferably among aluminum, zirconium, magnesium and boron and mixtures of these Metals is selected.

To In a particularly preferred embodiment, the inorganic Oxidizing agent ammonium perchlorate, the organic nitro explosive Hexogen (RDX), octogen (HMX), ONTA or a mixture of at least two of these three explosives, and the reducing metal aluminum.

The Azidoalkylformal the general formula I can as the sole plasticizer be used in appropriate compositions. But it can also in admixture with an inert plasticizer and / or Another energetic plasticizer, as on are known in this field.

Next The above-mentioned essential components may be new solid pyrotechnic compositions according to the Invention furthermore also one or more additives, as they usually do contained in this type of compositions, d. h., without the following enumeration limiting would be, for example, stabilizers, wetting agents, Antioxidants, catalysts for the reaction between the basic components of the polymer matrix, ballistic modifiers and Mündungsfeuerdämpfende means.

The solid pyrotechnic compositions according to the invention differ significantly from the known compositions by the partial or complete replacement of the energetic plasticizer by an azidoalkyl formal of the general formula I and can according to a method analogous to the known method with replacement all or part of the energetic plasticizer an azidoalkyl formal of general formula I are prepared.

If the polymer matrix is a polyurethane, z. B. first a premix is prepared, the at least one polyol, the Plasticizers, fillers and any added Contains additives. The plasticizer must with be miscible with the polyol to obtain a homogeneous mixture.

Subsequently if the premix is mixed with at least one polyisocyanate, by polycondensation of the OH functions of the polyol with the NCO functions of the polyisocyanate to produce the polyurethane.

Subsequently is the resulting impasto mixture in vacuo, preferably at a pressure of a few Torr, preferably during one Duration of about 0.5 h, and preferably at a temperature of 30 up to 60 ° C, kneaded.

After that This mixture is poured into a mold, whereupon the paste some Days, generally 10 to 20 days, cured at a temperature which is generally in the range of 10 to 90 ° C and preferably in the range of 40 to 70 ° C.

The The following examples illustrate the invention and the advantages obtainable by them, the data being non-limiting are.

Example 1 Synthesis of bis (2-azidoethyl) formal.

Into a stirred reactor equipped with a capacity of 100 ml, 50 ml of DMSO, 10 g (0.15 mol) of sodium azide and 3.46 g (0.02 mol) of bis (2-chloroethyl) formally, by reacting Formaldehyde with 2-chloroethanol in a H ₂ SO ₄ medium according to the procedure given above by Vinokurov (Chemical Abstracts 57: 16378c) using the variant prepared with ethanol introduced.

After 5 h stirring at 90 ° C, the reaction mixture is cooled and treated with 50 ml of water, whereupon it is extracted three times with 50 ml of CH ₂ Cl ₂ . The organic extract phases are combined and washed twice with 50 ml of water. After drying and evaporation under reduced pressure, 3.2 g (yield 87%) of bis (2-azidoethyl) are obtained formally in pure form, as shown by ¹ H-NMR analysis. The substance is in the form of a liquid with a density of 1.181 g / ml, a refractive index n _D of 1.470 and a Melting point of -109 to -112 ° C before. The heat of formation is +1.3 kJ / g (+311 cal / g), ie +243 kJ / mol (+58 kcal / mol).

Example 2 Preparation of a Solid Polymer Matrix for proppergols using bis (2-azidoethyl) formal as a plasticizer.

By Premixing a diethylene glycol polyadipate with terminal Hydroxy groups and obtained in Example 1 bis (2-azidoethyl) formal a premix was prepared which was then treated with biuret trihexane isocyanate (BTHI), after which several hours at 40 ° C in Vacuum was kneaded. This was followed by 14 d at Polymerized at 60 ° C.

On this way a solid, plasticized polymer matrix was obtained, consisting of 70% by mass of bis (2-azidoethyl) formal and 30% by mass Reaction of the polyol with polymer obtained from BTHI (functionality ratio NCO / OH = 1.20).

The Burning speed of this matrix, with the beach Burner on corresponding bars was 6.6 mm / s at a pressure of 7 MPa.

Parallel For this purpose, a prior art comparative experiment carried out in which the bis (2-azidoethyl) formally by Nitroglycerin has been replaced and all other conditions are the same were. The burn rate achieved was 5.3 mm / s at one Pressure of 7 MPa.

The Use of bis (2-azidoethyl) formally leads accordingly to an increase in the burning speed.

Example 3 Preparation of a Solid Polymer Matrix for proppergols using a mixture of bis (2-azidoethyl) formal and TMETN as a plasticizer.

• – 65 Masse-% Plastifizierungsmittel, das aus einem Gemisch von Bis(2-azidoethyl)formal aus Beispiel 1 und TMETN im Massenverhältnis 70/30 bestand;
• – 35 Masse-% eines durch Umsetzung von BTHI mit einem Azidogruppen enthaltenden Polyepichlorhydrin mit endständigen Hydroxygruppen (PAG) erhaltenen Polymers.

In the same manner as in Example 2, a plasticized solid polymer matrix was prepared, which consisted of:

• - 65 mass% plasticizer, which consisted of a mixture of bis (2-azidoethyl) formally from Example 1 and TMETN in the mass ratio 70/30;
• 35% by weight of a polymer obtained by reaction of BTHI with an azido group-containing polyepichlorohydrin (PAG).

The Burning rate of this matrix was 12.4 mm / s at 7 MPa.

Parallel For this purpose, a prior art comparative experiment carried out in which the bis (2-azidoethyl) formally by TMETN was replaced, all other conditions being identical were. The obtained burning rate was in this case 7.5 mm / s at 7 MPa.

The Use of bis (2-azidoethyl) formally leads accordingly to an increase in the burning speed.

Example 4 Preparation of a solid dibasic Composite propellant.

First was a premix of 28 mass% PAG, 2 mass% nitrocellulose and 70 mass% plasticizer produced, the used Plasticizer made from a mixture of bis (2-azidoethyl) formal from Example 1 and TMETN in the mass ratio 70/30. Then, the filler was powdered ammonium nitrate added in such an amount that the filler content 65% by mass in the resulting propellant, and then BTHI in added in such an amount that the ratio NCO / OH 1.20. This was followed by about 0.5 h at 40 ° C kneaded in vacuo, whereupon 14 d polymerized at 60 ° C. has been.

you So received a solid pyrotechnic composition, which is a composite dibasic propellant which consisted of a plasticized Polymer matrix with filler content consisted, in which the powdered Filler, the ammonium nitrate, 65% by weight and the plasticized Polymer matrix 35% by mass. This plasticized polymer matrix itself consisted of 35% by mass of one by reaction of BTHI Polyurethane obtained with PAG and nitrocellulose and 65% by mass Plasticizer containing a mixture of bis (2-azidoethyl) formal and TMETN in mass ratio 70/30.

The Burning speed of this Propergols, with the beach Burner on rods was 13 mm / s at 7 MPa and 41.6 mm / s at 13 MPa. The familiar to those skilled in the art Cone process certain critical diameter was about 45 mm.

Parallel For comparison, two propellants were prepared, the corresponded to the state of the art.

At the In the first comparative Propergol, the plasticizer was a mixture of nitroglycerin and BDNPAF in mass ratio 70/30.

At the second comparative propellant was the plasticizer from a mixture of TMETN and BTTN in mass ratio 50/50.

The rest Conditions were otherwise identical. These two the state of the Technology corresponding comparative Propergole differed correspondingly from the propellant according to the invention Example 3 only in the nature of the plasticizer.

At the first comparative propellant, the burning rate was 7.5 mm / s at 7 MPa and 11.5 mm / s at 13 MPa. The after the cone process certain critical diameters were less than 20 mm.

At the second comparative propellant, the burning rate was 7.6 mm / s at 7 MPa and 11 mm / s at 13 MPa. The after cylinder process certain critical diameter was 35 mm. It should be noted that the values obtained on cylinders are generally higher lie as the values determined on cones.

In summary It should be noted that the inventive Use of bis (2-azidoethyl) formally as plasticizer on the one hand a very pronounced increase in Burning speed of Propergols and on the other hand, a reduction sensitivity and vulnerability allowed.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 4440687 [0005]
• US 4141910 [0006]

Cited non-patent literature

• - DM Vinokurov in Izv. Vysshikh Uchebn. Zavedenii, Khim-i Khim. Tekhnol. 4, 988-91 (1961) [0016]

Claims (9)

Azidoalkylformale of the general formula I,

in which: n is an integer, with the condition 1 ≦ n ≦ 3, and R ₁ and R _{2 ,} which may be identical or different, are H or CH _{3 .} Azidoalkylformal of formula I according to claim 1, in which n 1 and R ₁ and R _{2 are} each hydrogen. A process for the synthesis of azidoalkylformals of general formula I according to claim 1, characterized by reacting a metal azide with a bis (haloalkyl) formal of general formula II,

in which: X is a halogen atom, n is an integer, with the condition 1 ≦ n ≦ 3, and R ₁ and R _{2 ,} which may be identical or different, are H or CH _{3 .} Process according to Claim 3, characterized by reaction a bis (haloalkyl) formal of the formula II in which X is a chlorine atom means with an alkali azide as metal azide. A method according to claim 3 or 4, characterized by using a bis (haloalkyl) formal of the general formula II which is obtained by reacting formaldehyde or acetaldehyde with a haloalkanol of the general formula III,

in which X, n and R _{1 have} the above meaning, is prepared in an acidic medium. Solid pyrotechnic compositions, essentially from a plasticized and filled Polymer matrix, wherein the filler powder is and at least one inorganic oxidizing agent or a contains organic nitro explosive, thereby alkylformal of the general formula I according to claim 1 or 2 and preferably Bis (2-azidoethyl) is formal. Solid pyrotechnic compositions according to claim 6, characterized in that the polymer matrix of nitrocellulose, a polyester, a polyether or a polyurethane and the filler contains an inorganic oxidizing agent, preferably ammonium perchlorate, potassium perchlorate, ammonium nitrate and sodium nitrate and mixtures of these substances is. Solid pyrotechnic compositions according to claim 7, characterized in that the filler further also contains an organic nitro explosive. Use of the Azidoalkyl Formals of the General Formula I according to claim 1 or 2, preferably of bis (2-azidoethyl) formal, as plasticizer in solid pyrotechnic compositions.