SE531839C2 - The substance 4,4-dinitro-1,7-diazidoheptane, a plasticizer for an explosive or propellant comprising the substance and use of the substance - Google Patents

Description

The plasticizers have had disadvantages such as low thermal stability, sometimes, low energy content, high migration capacity and, they also dissolve the filler. The low thermal stability can be remedied with stabilizers, but finding a molecule that is stable as such is a very interesting area of research.

Recently, attention has been drawn to gem-dinitro-based plasticizers. Great efforts have been made for industrial scale production of BDNPF / A and to develop similar mixtures containing gem dinitro alcohol formulas. The last decade's research has mostly focused on azido plasticizers. These considerations directed our efforts toward structures with energetically derived gem-dinitro substances. The high energy content is an advantage of the azido group.

According to the invention, a new diazido substance has been synthesized, i.e. 4,4-dinitro-1,7-diazidoheptane (DNHDA) of the formula NO2 N3 / \ / \ t / \ / \ N3 NO2 DNHDA has a density of 1.51 g / cm3, an oxygen balance of -90.7% and a calculated heat of formation of -123.38 kJ / mol.

The glass transition temperature of the substance is -89.7 ° C. DNHDA's performance in combination with good emollient ability, low sensitivity and high chemical compatibility means that the substance is interesting as an ingredient in fuel as well as an explosive. The substance has, in contrast to several other plasticizers, very good thermal stability. Another difference from many other commercially available energetic plasticizers is the low glass transition temperature. .ex.

(PBX), plastically bonded explosives composite powder for cannons and rockets.

A PBX contains a powerful explosive such as RDX, HMX, CL-20 and a polymeric binder system. Non-energetic binders such as HTPB have been used for a long time.

Energetic binders, such as polyglycidylazide (GAP), have been used in experimentally pressed and form-cured PBXs not reached for underwater purposes, but they are likely to have military use yet. Energetic softeners are more common in PBXs. Examples of such plasticizers are BDNPA / F [bis (2,2-dinitropropyl) acetal and bis (2,2-dinitropropyl) formal], BTTN [1,2,4-butanetriol trinitrate], TMETN [trimethylolethane trinitrate], TEGDN [triethylene glycol dinitratl, FEFO [bis (2-fluoro-2,2-dinitroethyl) formal] and K10 [dinitroethylbenzene / 2,4,6-trinitroethylbenzene (65/35)], also called Rowanite 8001.

Cannon composite gunpowder contains an oxidizing agent and a binder system. In modern Low Vulnerability Ammunition (LOVA) cannon gunpowder, high-energy substances such as RDX and HMX are often used as oxidizing agents. A number of polymeric binder systems including plasticizers have been used. New combinations of energetic binders and plasticizers are still being tested to increase performance without compromising the LOVA properties. Composite powder for rockets also contains an oxidizing agent and a binder system. The oxidizing agents commonly used include nitrate salts of non-metals, alkali metals and alkaline earth metals, dinitramides, perchlorates, chlorates and chlorites. More specific examples of oxidizing agents for ammonium rocket powder are ammonium nitrate, potassium nitrate, perchlorate, potassium perchlorate, ammonium dinitramide and potassium dinitramide. The binder may be an inert or an energetic polymer or any other binder system well known in the art.

By thermochemical calculations (Cheetah 2.0, Fried, L.

E .; Howard, W. M .; Souers, P. C .; Lawrence Livermore National Laboratory, 1998.) estimates of the energetic properties of DNHDA have been made. The explosive capacity is calculated for the pure molecule in terms of relative work compared to HMX (V / V @ = 2.2). Fuel capacity is calculated as a specific impulse for the pure substance and a comparison is made against a conventional rocket fuel comprising ammonium perchlorate in a binder of hydroxyl-terminated polybutadiene, AP / HTPB (85/15% by weight).

Table 1. Calculated capacity for pure DNHDA in comparison with HMX.

Detonation- 6001 m / s HMX 9300 m / s speed Detonation- 12.57 HMX 39.3 GPa pressure Expansion energy 36% (V / VOIZ, Specific impulse 184 s AP / HTPB (85/15) (rocket) 244 s 10 15 20 š3% B39 The following performance has been calculated for different propellant mixtures based on 70% by volume of ammonium dinitramide (AND) and 30% by volume of binder The binders are hydroxyl-terminated polybutadiene (HTPB), poly-3,3-bis (azidomethyl oxetane / glycidylazide polymer (BAMO / GAP), BAMO / GAP containing the known plasticizer dinitroethylbenzene (DNEB) and BAMO / GAP containing the plasticizer according to (DNHDA). 10 BAMO / GAP- (TDI) (BAMO / GA? / TDI) invention 4 , 4-dintro-1,7-diazidoheptane volume% of the binder consists of the plasticizer, the plasticizer is crosslinked with toluene diisocyanate and the binder without plasticizer consists of 64.8 / 24.0 / 11.2% by weight.Pc = 68 atm, Pe = l atm, charge density 0.2 g / cm3 Code: Cheetah 2.0.

Table 2. Comparison of calculated properties of different mixtures Binder Specific impulse (s) Force (Y / q) HTPB 243 1228 BAMO / GAP 262 l328 BÅMO / GÄP / DNEB 261 1314 BÅMO / GÅP / DNHDÅ 264 l339 You can read from Table 1 that DNHDA is not a powerful explosive. On the other hand, the calculations show that a mixture with the plasticizer according to the invention has an impulse and force which is better than current NC-based fuels, which is normally in the range 200-230 s and 1100-1200 J / g, respectively. The calculations also show that DNHDA, (DNEB>), in contrast to dinitroethylbenzene, enhances the performance of the GH BAMO / GAP blend.

The new substance can be prepared by a Michael reaction between a metal salt of dinitromethane and a suitable Michael acceptor such as acrylic acid or methyl acrylate. In the latter case, the ester formed is subjected to hydrolysis in acidic conditions. Reduction of the acid gives the corresponding diol whose hydroxyl group is converted to suitable leaving groups. Substitution with a metal azide gives the final product.

The preparation of the substance is illustrated by the following examples.

A Bruker 400 MHz spectrometer was used to record NMR spectra. Melting point and probe temperature were determined with a Mettler DSC 30. Elemental analyzes were performed by H. Kolbe Mikro Analytisches Laboratorium, Muhlheim an der Ruhr in Germany. The density was determined with a pycnometer.

Example 1 Preparation of 4,4-dinitro-1,7-heptanedioic acid dimethyl ester.

Moist potassium dinitromethane, corresponding to 43.2 g (0.30 mol; 1 eq.), Was mixed with 350 ml of deionized water.

The mixture was heated to 40 ° C. Methyl acrylate (139.2 g; 1.62 mol; 5.4 eq.) Was added over one hour. The reaction mixture was left at 40 ° C, with stirring, overnight. (3 x 100 ml).

The aqueous solution was extracted with ethyl ether. The combined organic phases were dried over Na 2 SO 4 in vacuo to give a viscous oil.

The oil crystallized upon addition of methanol. 51.2 g white, 1: 4 NMR The crude product was recrystallized from ethanol. needle-shaped crystals of sufficient purity were prepared.

(DMSO-da) δ = 3.6l3 (6H, s); 2.85 (4H, t, J 8); 2.49 (4H, δ 15 20 25 30 8233 7 t, J = 7.2), - Jc NMR (nMso-dé) δ = i71.8, - 125.0, - 52.7, - 29.5 , - 28.4.

Example 2 Preparation of 4,4-dinitro-1,7-heptanedioic acid. (51.2 g; Dimethyl-4,4-dinitroheptanedionate 0.18 mol) was mixed with 400 ml of 18% hydrochloric acid. The mixture was refluxed overnight. As the solution cooled, the product crystallized as white crystals. The precipitate was filtered off and washed with water. This gave 34.5 g of white crystals. The mother liquor was concentrated and left in the refrigerator overnight. A second batch of crystals was filtered off. A total of 43.7 g of 1 H NMR (DM 50 -do) was prepared. 541.97 (za, m) Δ), - 13 C NMR (nM 50 -ag) δ = 171.9o (s), - 22.22 28.92 (t); 27.80 (t). (yield 95%). (8): Example 3 Preparation of 4,4-dinitro-1,7-heptanediol (DNHDO).

(Warning: A large flask is recommended as the reaction can be initiated suddenly after the addition of TFA to the reaction mixture, with heavy release of hydrogen gas.) Trifluoroacetic acid (2.28 g; 20 mmol) was added dropwise to a solution of 4,4-dinitroheptanedioic acid (2.0 qi 8 mmol) (0.756 g; in dry THF (40 ml) at 0-5 and NaBH 4 20 mmol) ° C for 15 minutes. To prevent a violent reaction, a small amount of trifluoroacetic acid may be added to the mixture to start the reaction. As soon as the reaction started and hydrogen production was observed, the remaining amount of trifluoroacetic acid was added dropwise.

When the addition was complete, the mixture was slowly warmed to room temperature and stirred at this temperature for 24 hours. Diluted HCl (20 mL, 1 mL) was added to quench the reaction. The reaction solution was then extracted with ethyl acetate (3 x 20 mL). The organic phases were combined, washed with water (3 x 10 mL), dried over Na 2 SO 4 and evaporated to a white solid. Pure product can be obtained by recrystallization from methylene chloride. (1.3 g; 74.3%); mp 71.5-72 ° C (lit: 74.545 ° C>, - in NMR (δ, ppm, cm t, 2 H, ç fi y = 5.2 Hz); 3.53 (q, 4H, QQH = 5.6 Hz).

Example 4 Preparation of 4,4-dinitro-1,7-dichloroheptane (DNHDC).

SOCl 2 (2.38 g; 20 mmol) was added dropwise, at 0-5 ° C, to the mixture consisting of 4,4-dinitro-1,7-heptanediol (1,11 g; (0.79 g; 10 mmol) .

The reaction mixture was slowly warmed to room mmol (5 mmol) and pyridine temperature when the reaction was complete and heated and then refluxed for 4 hours in a nitrogen atmosphere. The light brown reaction mixture was cooled to room temperature and the excess SOCl 2 was removed under reduced pressure. On the obtained residue, flash chromatography on silica gel with CHCl 3 as eluent is challenged to obtain a light yellow oil. (1.0 g; 85.0%); 1 H NMR (δ, ppm, CD 3 CN): 1.77 (m, 4H); 2.66 (m, 4H); 3.65 (t, 4H, Jmf = 6.0 H2).

Example 5 Synthesis of 4,4-dinitro-1,7-diazidoheptane (DNHDA): The mixture of 4,4-dinitro-1,7-dichloroheptane (1.04 g 4 mmol), sodium azide (1.04 g; 16 mmol and Na 2 O (0.5 g; 1.0 mmol) in DMSO (20 mL) were heated at 50 ° C for 16 h. The reaction mixture was cooled to room temperature and diethyl ether (60 mL) was added. The organic phase was washed with 53% 839 water (4 x 20 ml) to remove DMSO, dried over Na 2 SO 4, passed through a short column of silica gel and evaporated to give a light yellow oil (0.82 q; 75.4%). Tg: -s9.7 ° C, -1H NMR (δ, ppm, cD3cN> = 1.58 (m, 4H), - 2.61 (m, 4H); 3.43 (t, 4H ,. Lm = 6.6 Hz); Elemental analysis: calculated for C , 41.06.

Claims (6)

10 15 20 25 53% 839 10 Patent claims 1. 1. The substance 4,4-dinitro-1,7-diazidoheptane. A plasticizer for use in a polymeric binder system for an explosive or propellant mixture, the carnelian plasticizer comprises 4,4-dinitro-1,7-diazidoheptane. The use of 4,4-dinitro-1,7-diazidoheptane as a plasticizer in a polymeric binder system for an explosive or propellant mixture. The use according to claim 3, wherein the polymeric binder system is based on a glycidyl azide polymer (GAP). The use according to claim 3, wherein the binder system is based on a poly-3,3-bis (azidomethyl) oxetane (BAMO). The use according to claim 3, wherein the binder system is based on a poly-3,3-bis (azidomethyl) oxetane / glycidyl azide polymer (BAMO / GAP).