Inner salt type high-energy density insensitive explosive and preparation method thereof

Abstract

The invention discloses an inner salt type high-energy density insensitive explosive and a preparation method thereof, 9-amino-2, 6-dinitro-bis [1, 2, 4] triazolo [1, 3, 5] triazine, namely ZDTT, is prepared, and the ZDTT has the performance advantages of high energy density and insensitivity and also has the advantage of simple synthesis process; zDTT has a unique inner salt type condensed ring structure and is insoluble in water and conventional organic solvents. The ZDTT actual measurement density is 1.881 g.cm <-3 >, the detonation velocity is 8757 m.s <-1 >, the detonation pressure is 31.7 GPa, the initial thermal decomposition temperature is 330 DEG C, the impact sensitivity is larger than 40 J, the friction sensitivity is larger than 360 N, and the high-energy-density insensitive explosive has huge application potential in the field of high-energy-density insensitive explosives.

Description

Technical Field

[0001] This invention relates to the field of energetic materials technology, and in particular to an internal salt type high energy density insensitive explosive and its preparation method. Background Technology

[0002] Current energetic materials generally cannot simultaneously meet the requirements of high energy and low sensitivity, which severely restricts the development of weaponry. The design and synthesis of novel high-energy-density insensitive explosives has become a core technical challenge that urgently needs to be overcome in the field of energetic materials.

[0003] In recent years, nitrogen-rich heterocyclic compounds have become a research hotspot in the field of energetic materials due to their unique molecular properties. Many high-energy compounds have been successfully constructed by introducing typical explosive groups such as nitro (-NO2) into the polynitrogen framework, but their safety performance remains limited. Fused-ring compounds possess advantages such as multi-ring coplanar configuration, a large π-π conjugated system, and high enthalpy of formation, which positively influence their energy density, sensitivity, and thermal stability. These characteristics can enable fused-ring energetic materials to overcome the performance bottleneck of "high energy, low sensitivity." Summary of the Invention

[0004] The purpose of this invention is to overcome the contradiction between high energy and low sensitivity in existing explosives, in order to meet the needs of modern weaponry development. Therefore, this invention provides an internal salt-type high-energy insensitive explosive and its preparation method. Using the previously reported 2,3,5,6-tetraamino-9-imino-bis(1,2,4-triazolo)1,3,5-triazine bromide (TCs-Br) as a substrate, this invention develops a low-cost synthetic method for an internal salt-type high-energy insensitive explosive and synthesizes a novel high-energy insensitive explosive, ZDTT, with excellent overall performance. This explosive has enormous application potential and value in the field of energetic materials.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] An internal salt type high-energy insensitive explosive, the structural formula of which is as follows:

[0007] .

[0008] In another aspect, this invention provides a method for preparing an internal salt-type high-energy insensitive explosive, which is carried out via the following synthetic route:

[0009] .

[0010] A further proposed method includes the following steps in the preparation process:

[0011] 2,3,5,6-Tetraamino-9-imino-bis(1,2,4-triazolo-1,3,5-triazine) bromide (TCs-Br) was added to a 20% wt H₂SO₄ aqueous solution and stirred continuously under ice bath conditions. Once the solution temperature was suitable, it was added to an aqueous NaNO₂ solution, maintaining a suitable reaction temperature during the dropwise addition. After the addition was complete, the solution was heated to 60°C and reacted for a sufficient time, resulting in the precipitation of a large amount of reddish-brown precipitate. This precipitate was then acidified to obtain a pale yellow precipitate, which is DNBTA.

[0012] DNBTA was added to an appropriate amount of organic solvent. First, Cs₂CO₃ was added for deprotonation, followed by BrCN for cyclization. The reaction was carried out under heating for a sufficient time. After the reaction was complete, a large amount of yellow precipitate precipitated. After filtration, the precipitate was washed with an appropriate amount of ice water and ethanol. The resulting solid was the cesium salt of ZDTT (ZDTT-Cs). ZDTT-Cs was acidified with sufficient trifluoroacetic acid (TFA) or concentrated sulfuric acid, then impurities were washed away with an organic solvent. After drying, the target product ZDTT was obtained.

[0013] A further embodiment is that the molar ratio of TCs-Br, H2SO4 and NaNO2 is 1 : (7~10) : (60~90).

[0014] A further embodiment involves maintaining the reaction temperature at 0-5°C during the mixing process of the 20%wt H2SO4 solution and the NaNO2 aqueous solution.

[0015] A further step is to heat the solution to 58-62°C after the addition is completed, and the reaction time is 4-6 hours.

[0016] A further embodiment is that the organic solvent includes one or more of ACN, DMF, and DMSO. Using an appropriate amount of organic solvent means that the organic solvent can completely dissolve DNBTA.

[0017] A further embodiment is that the molar ratio of DNBTA, Cs2CO3 and BrCN is 1 : (1~2) : (1~2).

[0018] A further embodiment is that the reaction temperature of DNBTA, Cs2CO3 and BrCN is 60~80℃.

[0019] A further embodiment involves reacting DNBTA, Cs2CO3, and BrCN under heating conditions for 1–2 hours.

[0020] In step (1), acidification involves adding acid to the mixture. This means that:

[0021] The reddish-brown precipitate obtained from each 0.5g~1g TCs-Br preparation should be acidified with at least 10ml of 20%wt H2SO4 aqueous solution;

[0022] In step (2), acidification of ZDTT-Cs using sufficient trifluoroacetic acid (TFA) or concentrated sulfuric acid means:

[0023] ZDTT-Cs prepared from 0.5g to 1g of DNBTA should be acidified with at least 20ml of TFA or concentrated sulfuric acid.

[0024] Internal salt type high-energy insensitive explosives are applied in the field of energetic materials.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention discloses an internal salt-type high-energy insensitive explosive and its preparation method, which yields 9-amino-2,6-dinitro-bis[1,2,4]triazolo[1,3,5]triazine, i.e., ZDTT. Besides its advantages of high energy density and low sensitivity, ZDTT also boasts a simple manufacturing process. Single-crystal X-ray diffraction analysis shows that ZDTT possesses a unique internal salt-type fused-ring structure and is poorly soluble in water and common organic solvents. The measured density of ZDTT is as high as 1.881 g·cm³. -3 The detonation velocity is 8757 m / s. -1 It has an explosive pressure of 31.7 GPa, an initial thermal decomposition temperature of 330℃, a measured impact sensitivity greater than 40 J, and a friction sensitivity greater than 360 N, and has great application potential in the field of high energy density insensitive explosives. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a molecular structure diagram of the internal salt type high-energy insensitive explosive ZDTT of the present invention.

[0029] Figure 2 This is a crystal structure diagram of the internal salt type high-energy insensitive explosive ZDTT·2(1,4-dioxane) of the present invention;

[0030] In the figure, (a) is the asymmetric unit of ZDTT·2(1,4-dioxane), (b) is the absolutely symmetric ZDTT molecular structure observed along the c-axis, (c) is the nearly planar ZDTT molecule observed along the b-axis, (d) is the crystal packing diagram of ZDTT·2(1,4-dioxane) observed along the a-axis or b-axis, and (e) is the crystal packing diagram of ZDTT·2(1,4-dioxane) observed along the c-axis. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] Example 1. Synthesis of DNBTA

[0033] Weigh 0.634 g of TCs-Br and dissolve it in 7 mL of 20% wt H2SO4. Simultaneously, dissolve 10.80 g of NaNO2 in 15 mL of water. Stir both solutions in an ice bath for 10 minutes. Then, slowly add the dilute sulfuric acid solution of TCs-Br to the sodium nitrite aqueous solution (the molar ratio of TCs-Br, H2SO4, and NaNO2 is approximately 1:8:78), maintaining the reaction temperature within the range of 0–5 °C. After mixing all the solutions, heat the solution to 60 °C and react for 4 hours. After the reaction is complete, stop stirring, and a large amount of reddish-brown precipitate will precipitate. Acidify this precipitate by adding sufficient 20% wt H2SO4 aqueous solution (not less than 10 mL), yielding a pale yellow precipitate, which is DNBTA, with a yield of approximately 56%.

[0034] Example 2. Synthesis of DNBTA

[0035] Weigh 0.951 g of TCs-Br and dissolve it in 12 mL of 20% wt H2SO4. Simultaneously, dissolve 14.49 g of NaNO2 in 15 mL of water. Stir both solutions in an ice bath for 10 minutes. Then, slowly add the dilute sulfuric acid solution of TCs-Br to the sodium nitrite aqueous solution (the molar ratio of TCs-Br, H2SO4, and NaNO2 is approximately 1:9:70), maintaining the reaction temperature within the range of 0–5 °C. After mixing all the solutions, heat the solution to 60 °C and react for 5 hours. After the reaction is complete, stop stirring, and a large amount of reddish-brown precipitate will precipitate. Acidify this precipitate by adding sufficient 20% wt H2SO4 aqueous solution to obtain a pale yellow precipitate, which is DNBTA, with a yield of approximately 65%.

[0036] Example 3. Synthesis of ZDTT, a high-energy insensitive explosive

[0037] Weigh 0.482 g of DNBTA and dissolve it in 10 mL of DMF. After complete dissolution, add 0.652 g of Cs₂CO₃ and 0.212 g of BrCN (the molar ratio of DNBTA, Cs₂CO₃, and BrCN is 1:1:1). Then heat to 60 °C and react for 2 h. After the reaction is complete, filter the solution after it has cooled to room temperature, wash with a small amount of ice water and ethanol, and air dry. Acidify the obtained solid ZDTT-Cs with 20 mL of TFA, then wash away impurities with DMF, and dry to obtain the target product ZDTT with a yield of approximately 50%. Its basic properties and performance information are shown in Table 1.

[0038] Table 1. Properties and characteristics of compound ZDTT

[0039] compound <![CDATA[ρ (g∙cm -3 ) a ]]> <![CDATA[∆ f H m (kJ∙mol -1 ) b ]]> <![CDATA[T d (℃) c ]]> <![CDATA[D (m s -1 ) d ]]> <![CDATA[P (GPa) e ]]> <![CDATA[IS (J) f ]]> <![CDATA[FS (N) g ]]> ZDTT 1.88 481.7 330 8757 31.7 >40 >360

[0040] Example 4. Synthesis of ZDTT, a high-energy insensitive explosive

[0041] Weigh 0.482 g of DNBTA and dissolve it in 10 mL of DMF. After complete dissolution, add 0.978 g of Cs₂CO₃ and 0.318 g of BrCN (the molar ratio of DNBTA, Cs₂CO₃, and BrCN is 1:1.5:1.5), and then heat to 70 °C for 1 h. After the reaction is complete, allow the solution to cool to room temperature, filter, wash with a small amount of ice water and ethanol, and air dry. The obtained solid ZDTT-Cs is acidified with 30 mL of TFA, then washed with ACN to remove impurities, and dried to obtain the target product ZDTT, with a yield of approximately 65%.

[0042] Example 5. Synthesis of ZDTT, a high-energy insensitive explosive

[0043] 0.482 g of DNBTA was dissolved in 5 mL of DMF. After complete dissolution, 0.978 g of Cs₂CO₃ and 0.318 g of BrCN (the molar ratio of DNBTA, Cs₂CO₃, and BrCN was 1:1.5:1.5) were added, and the mixture was heated to 80 °C for 1 h. After the reaction was complete, the solution was cooled to room temperature and filtered. It was then rinsed with a small amount of ice water and ethanol and allowed to air dry. The obtained solid ZDTT-Cs was acidified with 30 mL of TFA, then washed with ACN to remove impurities. After drying, the target product ZDTT was obtained, with a yield of approximately 84%. 10 mg of the obtained ZDTT was dispersed in 5 mL of 1,4-dioxane and sonicated to promote dissolution. Undissolved ZDTT was filtered off, and the filtrate was placed in a refrigerator to culture crystals, yielding ZDTT·2(1,4-dioxane) crystals, the structure of which is shown below. Figure 2 As shown.

[0044] This invention discloses an internal salt-type high-energy insensitive explosive and its preparation method, which produces 9-amino-2,6-dinitro-bis[1,2,4]triazolo[1,3,5]triazine, i.e., ZDTT. In addition to its advantages of high energy density and low sensitivity, ZDTT also has the advantage of a simple synthesis process, making it of significant practical application value.

[0045] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. Furthermore, various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the spirit of the present invention, they should also be considered as the content disclosed in the present invention.

Claims

1. An internal salt-type high-energy insensitive explosive, characterized in that: The structural formula is as follows: 。 2. A method for preparing an internal salt-type high-energy insensitive explosive, characterized in that: The following synthetic route was used for preparation: 。 3. The method for preparing the internal salt type high-energy insensitive explosive according to claim 2, characterized in that: The preparation method includes the following steps: (1) Add TCs-Br to an aqueous solution of H2SO4 and stir continuously under ice bath conditions. Then add it to an aqueous solution of NaNO2. After the addition is complete, heat the solution until a large amount of reddish-brown precipitate is precipitated. Then add it to acid for acidification to obtain a light yellow precipitate, which is DNBTA. (2) Add DNBTA to an appropriate amount of organic solvent, then add Cs2CO3 and BrCN, react under heating conditions, after the reaction is completed, filter and wash the solution after it is cooled to room temperature, acidify the obtained solid with acid, then wash away the impurities with organic solvent, and dry to obtain the target product ZDTT.

4. The method for preparing the internal salt type high-energy insensitive explosive according to claim 3, characterized in that: In step (1), the molar ratio of the three reaction raw materials TCs-Br, H2SO4 and NaNO2 is 1: (7~10): (60~90); in step (2), the molar ratio of the three reaction raw materials DNBTA, Cs2CO3 and BrCN is 1: (1~2): (1~2).

5. The method for preparing the internal salt type high-energy insensitive explosive according to claim 3, characterized in that, The H2SO4 aqueous solution of the raw material is 10~30%wt H2SO4 aqueous solution, and the reaction temperature of the mixing process of the H2SO4 solution of the raw material and the NaNO2 aqueous solution is maintained at 0~5℃.

6. The method for preparing the internal salt type high-energy insensitive explosive according to claim 3, characterized in that, After the addition in step (1) is completed, the solution is heated to 58~62℃ for reaction, and the reaction time is 4~6 hours.

7. The method for preparing the internal salt type high-energy insensitive explosive according to claim 3, characterized in that, The organic solvent mentioned in step (2) includes one or more of ACN, DMF, and DMSO, and an appropriate amount of organic solvent is used to completely dissolve DNBTA.

8. The method for preparing the internal salt type high-energy insensitive explosive according to claim 3, characterized in that, The reaction temperature of DNBTA, Cs2CO3 and BrCN is 60~80℃, and the reaction time of DNBTA, Cs2CO3 and BrCN under heating conditions is 1~2h.

9. The method for preparing the internal salt type high-energy insensitive explosive according to claim 3, characterized in that, Step (1), acidifying the reddish-brown precipitate by adding acid, refers to: The reddish-brown precipitate obtained from each 0.5g~1g TCs-Br preparation is acidified with at least 10ml of 20%wt H2SO4 aqueous solution.

10. The method for preparing the internal salt type high-energy insensitive explosive according to claim 3, characterized in that, The acid used in step (2) acidification is concentrated sulfuric acid or trifluoroacetic acid.

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