RU2343150C1 - 3-(3,5-dinitropyrazol-4-yl)-4-nitrofurazan, method of obtaining it and its application as thermostable explosive substance - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to 3-(3,5-dinitropyrazol-4-yl)-4-nitrofurazan of formula I, method of its obtaining and its application as thermostable explosive substance.

. Method of obtaining lies in interaction of 3-nitrofurazan-4-acetic acid with mixture of dimethylformamide and phosphorus chloroxy, with further processing of reaction mixture with water acid solution, or its alkali or alkali earth salt, obtained salt of trimethyn derivative is processed with hydrazine or its derivatives, with further nitrating of obtained 3-(pyrazol-4-yl)-4-nitrofurazan with sulphur-nitrogen nitrating mixture at heating.

EFFECT: compound of formula I can be applied as component of explosive compositions, solid propellant and power-intensive compositions for various purposes, used at higher temperatures.

3 cl, 2 dwg, 1 ex

Description

The present invention relates to a new compound - 3- (3,5-dinitropyrazol-4-yl) -4-nitrofurazan of the general formula (1):

the method of its production and its use as a heat-resistant explosive.

The proposed compound can be used as a component of explosive compositions, solid rocket fuels and energy-intensive compositions for various purposes, operated at elevated temperatures (for example, during drilling and blasting operations in deep mines). Also, the compound (1) can serve as an intermediate for the synthesis of analogues and can find application in organic synthesis.

3- (3,5-Dinitropyrazol-4-yl) -4-nitrofurazan is a compound, the molecule of which still contains a sequence of atoms and bonds that have not been encountered simultaneously, representing a trinitroderivative, obtained on the basis of a molecule including furazanic and pyrazole cycles. The combination of nitrofurazanyl and dinitropyrazole fragments in one molecule gives it the positive qualities inherent in both derivatives of furazan and pyrazole. The compound (1) and its properties, as well as the method for its preparation, are not described in the literature.

The literature describes a substance consisting of two dinitropyrazole fragments - tetranitrobipyrazole (2) [ILDalinger, T.K.Shkinyova, SAShevelev, VSKuzmin, E.A. Arnautova, T. S. Pivina. Proc. 29 ^th International ICT-Conference, Energetic Materials - Production, Processing and Characterization, June 30 - July 3, 1998, Karlsruhe, FRG, 57 / 1-13]. Compound (2) is prepared by nitration of bipirazole (3) (nitration details are not reported).

Compound (2) is a heat-resistant high-melting explosive, but has not very high explosive characteristics (see table).

Note that compound (2) includes only one type of heterocyclic structural fragments — it contains a pyrazole instead of a furazan ring. Moreover, four nitro groups are included in the composition of compound (4).

It is known the substance adopted for the prototype, consisting of two five-membered heterocycles connected by a simple bond, including a nitrofurazanyl fragment. So, during the oxidation of 4,4'-diaminobifurazan (5) with trifluoroacetic acid, 4,4'-dinitrobifurazan (4) was obtained [M. D. Coburn. J. Heterocycl. Chem., 1968, 5, 83], i.e. a compound comprising two nitrofurazanyl fragments. Compound (4) is a more powerful explosive than compound (2), however, it has a low melting point (see table), which limits its scope.

It should be noted that compound (4), firstly, instead of the pyrazole contains a furazan cycle, secondly, it contains only two nitro groups, and thirdly, it does not and cannot have any substituents, being the only possible representative of this type of molecule .

It is not possible to obtain compound (1) in this way, since the corresponding triamine derivative is not known. Moreover, successful examples of the preparation of polynitro compounds by oxidation of aminoazoles containing three amino groups are not known.

The present invention is the creation of a new nitro compound containing both furazan and pyrazole rings, which is a new heat-resistant explosive with good explosive characteristics and having a high melting point, and the development of a method for its production.

The problem is achieved by the new compound - 3- (3,5-dinitropyrazol-4-yl) -4-nitrofurazan of the general formula (1)

and the method for its preparation, namely, that 3-nitrofurazan-4-acetic acid (6) is reacted with a mixture of dimethylformamide and phosphorus oxychloride, followed by treatment of the reaction mixture with an aqueous solution of an acid, or its alkaline or alkaline-earth salt, and obtained this slightly soluble salt of the trimethinium derivative (7) is treated with hydrazine or a derivative thereof, followed by nitration of the obtained 3- (pyrazol-4-yl) -4-nitrofurazan (8) with a sulfur-nitrogen nitrating mixture when heated according to the following scheme:

The proposed method for producing 3- (3,5-dinitropyrazol-4-yl) -4-nitrofurazan (1) includes three stages.

First stage. The initial 3-nitrofurazan-4-acetic acid is obtained by oxidation of 3-aminofurazan-4-acetic acid with an oxidizing mixture based on hydrogen peroxide by the known method (I.V. Tselinsky, S.F. Melnikova, M.P. Zelenov. Zhurnaya organic chemistry, 1996, 32, (5), 766-769). The interaction of 3-nitrofurazan-4-acetic acid (6) with a mixture of dimethylformamide and phosphorus oxychloride can occur at a temperature of from 20 to 110 ° C. As the temperature rises, the time required to complete the reaction decreases. To obtain poorly soluble trimethinium salt (7) as the acid, or its alkaline, or alkaline-earth salt, which is the source of the X ^- anion, you can use, for example, perchloric (X ^- = ClO ₄ ^- ), hydrofluoric (X ^- = BF ₄ ^- ), hexafluorophosphoric (X ^- = PF ₆ ^- ) and other acids.

Second stage. The condensation of salt 7 with hydrazine can be carried out in a wide pH range; alkaline and acidic conditions are also suitable, which are achieved either by adding different amounts of hydrazine hydrate, or by using hydrazine salts with organic or inorganic acids, as well as by introducing various acids or bases.

Third stage. Nitration is carried out only when heated. The process can be carried out at a temperature of from 50 ° C to the boiling point of nitric acid. To enhance the activity of the nitrating mixture, sulfuric acid can be strengthened or replaced with oleum.

The structure of intermediates and the target compound is proved by the data of elemental analysis, mass, IR, NMR spectra. X-ray diffraction analysis was also performed for compound 1 (see drawing).

Thus, the claimed compound is a derivative of a previously unknown combination of furazan and pyrazole rings with three nitro groups. The presence in the structure of the claimed compounds N-H fragment, allows you to replace the proton, synthesizing various derivatives, thereby adjusting the properties of the molecule.

The proposed method is based on the appropriate combination of three sequential reactions. The first is the conversion of α-R-acetic acid when treated with a mixture of dimethylformamide and phosphorus oxychloride (Wilsmaer reagent) to a trimethinium salt. The second, the formation of the pyrazole cycle in the interaction of the trimethinium salt with hydrazine. The latter is the introduction of two nitro groups into the pyrazole ring upon nitration with a sulfur-nitrogen mixture.

Only the totality of the sequence of actions and conditions taken for the synthesis of the compound of formula (1) and the selected starting compound made it possible to achieve one of these goals - to obtain a trinitro derivative containing, in its basis, furazan and pyrazole rings bound by a simple bond.

The proposed compounds can be used as a component of explosive compositions, solid rocket fuels and energy-intensive compositions for various purposes, operated at elevated temperatures (for example, during drilling and blasting operations in deep mines).

Currently, 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and 2,2 ', 4,4', 6,6'-hexanitrostilbene (GNS) are currently used as basic components of standard heat-resistant explosives. [Energy condensed systems. Brief Encyclopedic Dictionary. Ed. B.P. Zhukova, 2nd ed., M: Janus-K, 2000; J. Kohler, R. Meyer, Explosives. 4 ed., Weinheim: VCH, 1993].

As can be seen from the table, these compounds have high thermal stability, but have average energy and explosive characteristics (heat of formation, ΔH _f ⁰ ; detonation velocity, D, detonation pressure, P _CJ ). Both substances are nitro derivatives of benzene and do not include heterocycle fragments. An important property of TATB, GNS is its low sensitivity to mechanical stress (shock and friction).

A heat-resistant explosive is known in which two dinitropyrazole moieties are linked by a single bond, such as tetranitrobipyrazole (4) [ILDalinger, T.K.Shkinyova, SAShevelev, VSKuzmin, EAArnautova, TSPivina. Proc. 29 ^th International ICT-Conference, Energetic Materials - Production, Processing and Characterization, June 30 - July 3, 1998, Karlsruhe, FRG, 57 / 1-13.]. Compound (4) is a more powerful explosive than TATB and GNS, has good thermal stability and low sensitivity to mechanical stress.

Another standard blasting explosive, such as HMX {Energy Condensed Systems. Brief Encyclopedic Dictionary. Ed. B.P. Zhukova, 2nd ed., M: Janus-K, 2000; J.Kohler, R. Meyer, Explosives. 4 ed., Weinheim: VCH, 1993], superior in energy characteristics to both TATB and GNS, and compound 4. However, the octogen has a high sensitivity to mechanical stress.

An explosive such as 4,4'-dinitrobifurazan (2) surpasses the octogen in explosive properties. However, it has a similar sensitivity. In addition, compound (2) has a low melting point (see table) and increased volatility, which limits its application.

Table.
Comparative physical and thermochemical characteristics of the claimed substance 1 with analogues. TATB STS four 2 Octogen Compound 1 Empirical formula C ₆ H ₆ N ₆ O ₆ C ₁₄ H ₆ N ₆ O ₆ C ₄ N ₆ O ₆ C ₆ H ₂ N ₈ O ₈ C ₄ H ₈ N ₈ O ₈ C ₅ H ₁ N ₇ O ₇ Like the weight 258.15 354.24 228.08 314.13 296.16 271.11 The nitrogen content,% 32.55 23.72 36.85 35.67 37.84 36.17 Oxygen coefficient, k _O 0.40 0.19 0.75 0.62 0.67 0.67 Density, d, g / cm ³ 1.93 1.74 1.85 1.85 1.9 1.98 Mp, ° C 330 (decomp.) 318 (decomp.) 85 280 (decomp.) 280 (decomp.) 223,280 (decomp.) Heat of formation, ΔH _f ⁰ kcal / mol -36.85 +12.2 +101 +41 +17.9 +105 Knock speed, D, km / s 7800 7000 8938 8219 9160 8580 Knock Pressure, P _CJ , kbar 284 212 369 338 382 365

As can be seen from the table, the characteristic of compound (1) occupies an intermediate position between compounds (2) and (4), exceeds the characteristics of TATB and GNS and, in a number of indicators, approaches octogen, but is less sensitive than the latter to mechanical stress (shock and friction) )

Thus, a new compound is obtained, constructed from interconnected by a simple bond of the furazan and pyrazole cycles, including three nitro groups, which is a heat-resistant explosive, and a method for its preparation is developed. It should be noted that derivatives of furazan and pyrazole are widely used in the construction of explosives, however, a combination that includes both of these heterocycles and three nitro groups has not been used previously.

The present invention is illustrated by the following examples.

Example. To a mixture of 4 ml of dimethylformamide and 2.2 ml of phosphorus oxychloride, 3.46 g (0.02 mol) of 3-nitrofurazan-4-acetic acid are added (6). The reaction mixture was stirred at 95-100 ° C for 2 hours, and then cooled to 5-10 ° C and 4 ml of ethanol and a solution of 2.45 g (0.02 mol) of sodium perchlorate in 7 ml of water were added. The resulting suspension is left overnight at 0-5 ° C. The precipitate formed is filtered off, washed with isopropanol and dried in air. After recrystallization from acetic acid, 3.5 g (51%) of the trimethinium derivative (7, X ^- = ClO ₄ ^- ) perchlorate are obtained in the form of yellow needle crystals. Mp 158-159 ° C.

Found,%: C 31.90; N, 20.58; H 4.18.

C ₉ H ₁₄ Cl ₁ N ₅ O ₇ (339.69)

Calculated,%: C 31.82; N, 20.62; H 4.15

To a suspension of 1.7 g (0.005 mol) of trimethinium derivative perchlorate (7) in a mixture of 10 ml of ethanol and 1 ml of water was added 0.45 g (0.0033 mol) of sodium acetate trihydrate and heated to dissolve. A solution of 0.5 g (0.01 mol) of hydrazine hydrate and 0.5 ml of acetic acid in 3 ml of ethanol was added dropwise to the resulting solution with stirring. The reaction mixture was boiled for 2 hours and then evaporated to dryness. The residue was chromatographed on a silica gel column; chloroform was the eluent. 0.71 g (78%) of 3- (pyrazol-4-yl) -4-nitrofurazan (8) was obtained in the form of a light cream low melting substance.

Found,%: C 33.12; N 38.65; H 1.68

C ₅ H ₃ N ₅ O ₃ (181.11)

Calculated,%: C 33.16; N 38.67; H 1.67

To a mixture of 1.5 g of 100% nitric acid and 6 g of a 20% oleum was added 1 g (0.0055 mol) of pyrazole 8 and stirred at 100 ° C for 12 hours. The reaction mixture was cooled to room temperature, the product was filtered off, recrystallized from aqueous trifluoroacetic acid, and dried at 130-140 ° C. Received 0.5 g (33.3%) of the target 3- (3,5-dinitropyrazol-4-yl) -4-nitrofurazan (1) in the form of colorless small crystals, so pl. 222-223 ° C

Found,%: C 22.13; N 36.18; H 0.39

C ₅ H ₁ N ₇ O ₇ (271.11)

Calculated,%: C 22.15; N 36.17; H 0.37

Mass spectrum, m / z: 271 [M ⁺ ]. 225 [M ⁺ - NO ₂ ], 195 [M ⁺ - NO ₂ - NO], 167, 150, 135, 103, 77.54, 46.

IR spectrum (in KBr, ν, cm ^-1 ): 3332, 1576, 1564, 1556, 1536, 1480, 1452, 1428, 1404, 1356, 1336, 1268, 1220, 1184, 1056, 1000, 916, 880 , 844, 832, 816.

¹ H NMR Spectrum (DMSO-d ₆ , δ, ppm): 9.57 (NH).

¹³ C NMR spectrum (DMSO-d ₆ , δ, ppm): 93.7, 142.7, 153.2, 160.0.

Thus, a new compound is obtained, which is a trinitro derivative formed on the basis of a molecule that includes furazan and pyrazole rings bonded to each other, which is an insensitive heat-resistant explosive, and a method for its preparation has been developed.

Claims (3)

1. 3- (3,5-Dinitropyrazol-4-yl) -4-nitrofurazan of the formula (1):

2. The method of obtaining the compound according to claim 1, which consists in the fact that 3-nitrofurazan-4-acetic acid is reacted with a mixture of dimethylformamide and phosphorus oxychloride, followed by treatment of the reaction mixture with an aqueous solution of an acid or its alkaline or alkaline earth salt, and the resulting a poorly soluble salt of the trimethinium derivative is treated with hydrazine or its derivative, followed by nitration of the obtained 3- (pyrazol-4-yl) -4-nitrofurazan with a sulfur-nitrogen nitrating mixture under heating. 3. The use of 3- (3,5-dinitropyrazol-4-yl) -4-nitrofurazan (1) according to claims 1 and 2 as a heat-resistant explosive.

Images