Low-chlorine TATB crystal with uniform pore structure and preparation method thereof

Abstract

The invention discloses a preparation method of a low-chlorine TATB crystal with a uniform pore structure, which comprises the following steps: dissolving crude TCTNB in toluene, and filtering to remove toluene insoluble substances to obtain a TCTNB solution; introducing nitrogen to discharge air in the reactor, transferring the TCTNB solution into the reactor, adding deionized water, sealing and heating, then introducing ammonia gas for reaction, cooling to room temperature after the reaction is completed, and filtering to obtain crude TATB; adding the crude TATB into hot water, and carrying out ultrasonic dispersion to obtain a suspension; and carrying out ultrasonic-assisted boiling washing on the suspension, filtering, alternately washing with acetone and hot water, and drying to obtain the low-chlorine TATB crystal with a uniform pore structure. The pore size of the TATB crystal obtained by the preparation method provided by the invention is concentrated in the range of 60-100 nm, the position distribution is uniform, and the chlorine content is less than or equal to 0.35%. The method is simple in technological process, mild in condition and suitable for industrial preparation of high-quality insensitive explosives for nuclear weapons and conventional weapons, and has both safety and magnification.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microstructure regulation of energetic materials, and more particularly, the application relates to a low-chlorine TATB crystal with uniform pore structure and a preparation method thereof. BACKGROUND

[0002] Among numerous energetic materials, 2,4,6-triamino-1,3,5-trinitrobenzene (TATB) has attracted extensive attention due to its good thermal stability, high crystal density and extremely insensitive characteristics to friction and impact, and is a famous high-energy explosive, which is widely used in nuclear weapons and advanced conventional weapons. Although TATB has high safety and long storage life, its "excessive insensitivity" leads to corner failure and dead zone in complex geometry of the main charge, which directly threatens the reliable initiation of the system. Therefore, "designable fine-tuning" of the detonation sensitivity of TATB has become a key issue in contemporary insensitive explosive engineering.

[0003] The "hot spot theory" points out that the void structure inside the explosive has a control effect on the detonation behavior: when the shock wave penetrates the explosive containing voids, the voids are severely compressed and instantaneously collapsed within nanoseconds, resulting in a sudden rise in local temperature and the formation of high-temperature and high-pressure "hot spots". These "hot spots" become the nucleation centers of chemical reactions, and their number and intensity directly determine the thickness and propagation speed of the subsequent reaction zone. More importantly, the size, shape, number and spatial distribution of the voids must be within a "critical window" - if the voids are too small, the "hot spot" temperature is not enough to trigger the self-sustaining reaction, becoming a subcritical "dead spot"; if the voids are too large, the hot spot number density is too low, the reaction zone is lengthened, and the energy is not concentrated, which reduces the sensitivity; and when the size of the voids matches the shock pressure, the hot spot density and efficiency are optimal, forming a dense "supercritical hot spot array", which makes the reaction zone thin and the energy concentrated, thereby significantly improving the initiation sensitivity and corner propagation ability.

[0004] In current mass industrial production, the mainstream preparation process of TATB is chloro-containing synthesis. The common synthesis route is to use 1,3,5-trichlorobenzene (TCB) as the starting material, to obtain 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) by nitration, and then to obtain TATB by amination. This process has large production capacity, low cost and mature technology. However, during the process, the reaction byproduct NH4Cl forms micron-sized inclusions in the crystal, which are then removed through the process, leaving so-called "wormholes". These pores have uneven scales and random connectivity, and the residual chlorine impurities may cause interface aging, leading to batch fluctuations in sensitivity. Therefore, it is of great significance to regulate the micro-pore structure of TATB and obtain low-chlorine TATB with uniform pore structure. SUMMARY

[0005] An object of the present application is to solve at least the above problems and / or defects, and to provide at least the advantages to be described later.

[0006] To achieve these objects and other advantages of the present application, a method for preparing low-chlorine TATB crystals with uniform pore structure is provided, comprising the following steps: Step one, TATB amine synthesis, comprising: S11, dissolving the crude TCTNB in toluene, filtering to remove toluene insolubles, to obtain a TCTNB solution; S12, introducing nitrogen to remove air in the reactor, transferring the TCTNB solution into the reactor, adding deionized water, sealing and heating, then introducing ammonia for reaction, cooling to room temperature after reaction, and filtering to obtain crude TATB; Step two, TATB post-treatment, comprising: S21, adding crude TATB to hot water and ultrasonic dispersion to obtain a suspension; S22, ultrasonic-assisted boiling and washing of the suspension, filtering, alternating washing with acetone and hot water, and drying to obtain low-chlorine TATB crystals with uniform pore structure.

[0007] Preferably, in S11, the mass ratio of crude TCTNB to toluene is 10-12:100.

[0008] Preferably, in S11, a 0.22 μm microporous filter membrane is used for filtering; the content of filtered toluene insolubles is ≤0.2%.

[0009] Preferably, in S12, the mass ratio of deionized water to crude TCTNB in S11 is 25-27:21.

[0010] Preferably, in S12, the heating rate of sealing and heating is 3℃ / min-8℃ / min, and the temperature is raised to 130℃-150℃.

[0011] Preferably, in S12, the introduction rate of ammonia is 4kg / cm 2 -5kg / cm 2 , and the molar ratio of ammonia to TCTNB is 6-6.5:1.

[0012] Preferably, in S21, the temperature of hot water is 50℃-80℃; the mass ratio of crude TATB to hot water is 1:200-300.

[0013] Preferably, in S22, the specific method of ultrasonic-assisted boiling and washing is: transferring the suspension into an ultrasonic boiling and washing device, setting the jacket temperature, ultrasonic frequency, ultrasonic power, and stirring rate, and boiling and washing for 3h-5h.

[0014] Preferably, the jacket temperature is 50-80℃. The ultrasonic frequency is 20-120 kHz. The ultrasonic power is 10-40 W / L. The stirring rate is 200-400 rpm.

[0015] Preferably, in S22, the drying method comprises any one of normal temperature drying, vacuum drying and freeze drying.

[0016] The present application at least includes the following beneficial effects: the present application controls the reaction conditions of TATB amination synthesis by optimizing the TATB synthesis and post-treatment process, adopts ultrasonic-assisted boiling and washing process, and then combines with acetone-hot water alternate washing and drying, solves the problems of uneven pore size and random connectivity of TATB in the existing low-chlorine production process, and obtains TATB crystals with uniform and controllable pores and chlorine content below 0.35%; the TATB crystals obtained by the preparation method of the present application have pore size concentrated in the range of 60-100 nm, and the position distribution is uniform, and the chlorine content is below 0.35%; the preparation method of the present application has simple process flow and mild conditions, and is suitable for industrialized preparation of high-quality insensitive explosives for nuclear weapons and conventional weapons, and has safety and scalability.

[0017] Other advantages, objects, and features of the present application will be apparent to those skilled in the art from the following description, and will be understood by those skilled in the art upon reading and understanding the present application. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The pore distribution diagram of the low-chlorine TATB crystal with uniform pore structure prepared for Example 4; Figure 2 The pore distribution diagram of the TATB crystal prepared for Comparative Example 1. DETAILED DESCRIPTION

[0019] The present application will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement the present application according to the description.

[0020] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0021] Example 1 A preparation method of a low-chlorine TATB crystal with uniform pore structure, comprising the following steps: Step one, TATB amination synthesis, comprising: S11, 110 g of crude TCTNB was weighed into 1000 g of toluene, mechanically stirred for 40 minutes until completely dissolved, filtered using a 0.22 μm microporous filter, and the toluene insoluble content was measured to be 0.15%, meeting the requirement of ≤0.2%, obtaining a TCTNB solution; S12, nitrogen was introduced into the high-pressure reaction kettle to replace the air, the TCTNB solution was transferred into the high-pressure reaction kettle, 136 mL of deionized water was added, the high-pressure reaction kettle was sealed, and the temperature was raised to 150°C at a rate of 5°C / min; S13, ammonia was introduced into the high-pressure reaction kettle at a rate of 4.5 kg / cm 2 until the reaction was complete, the molar ratio of ammonia to TCTNB was 6.3:1, the reaction pressure was maintained at 1.2 MPa, and after the required amount of ammonia was introduced, it was cooled to room temperature, the high-pressure reaction kettle was opened, and the reaction mixture was poured out, filtered to obtain light yellow crude TATB 98.7 g; Step two, TATB post-treatment, including: S21, 2 g of crude TATB was added to 500 mL of hot water at 80°C, ultrasonic dispersion, and a uniform suspension was formed; S22, the suspension was transferred to an ultrasonic cooking device, the jacket temperature was maintained at 80°C, the process parameters were ultrasonic frequency 40 kHz, ultrasonic power 30 W / L, and stirring speed 300 rpm, and the ultrasonic assisted cooking was carried out for 5 hours, and then filtered; S23, after filtration, 300 mL of acetone and 300 mL of 80°C hot water were used to wash alternately three times, and vacuum drying was carried out at 45°C for 4 hours, obtaining low-chlorine TATB crystals with uniform pore structure.

[0022] Example 2 A method for preparing low-chlorine TATB crystals with uniform pore structure, comprising the following steps: Step one, TATB amine synthesis, including: S11, 110 g of crude TCTNB was weighed into 1000 g of toluene, mechanically stirred for 40 minutes until completely dissolved, filtered using a 0.22 μm microporous filter, and the toluene insoluble content was measured to be 0.15%, meeting the requirement of ≤0.2%, obtaining a TCTNB solution; S12, nitrogen was introduced into the high-pressure reaction kettle to replace the air, the TCTNB solution was transferred into the high-pressure reaction kettle, 136 mL of deionized water was added, the high-pressure reaction kettle was sealed, and the temperature was raised to 150°C at a rate of 5°C / min; S13, ammonia was introduced into the high-pressure reaction kettle at a rate of 4.5 kg / cm 2Ammonia gas was introduced into the high-pressure reactor at a rate of 6.3:1 until the reaction was complete. The reaction pressure was maintained at 1.2 MPa. After the required amount of ammonia gas was introduced, the reactor was cooled to room temperature. The high-pressure reactor was opened, the reaction mixture was poured out, and filtered to obtain 98.7 g of pale yellow crude TATB. Step 2, TATB post-processing, including: S21. Add 2g of crude TATB to 500mL of 80℃ hot water and disperse by ultrasonication to form a uniform suspension; S22. Transfer the suspension to an ultrasonic boiling and washing device, maintain the jacket temperature at 80℃, and use process parameters of ultrasonic frequency 40kHz, ultrasonic power 30W / L, and stirring speed 300rpm to perform ultrasonic-assisted boiling and washing for 3 hours, followed by filtration. S23. After filtration, wash three times alternately with 300 mL of acetone and 300 mL of 80 °C hot water, and dry under vacuum at 45 °C for 4 hours to obtain low-chlorinated TATB crystals with a uniform porous structure.

[0023] Example 3 A method for preparing low-chlorinated TATB crystals with a uniform porous structure includes the following steps: Step 1, TATB amination synthesis, including: S11. Weigh 110g of crude TCTNB and add it to 1000g of toluene. Stir mechanically for 40 minutes until completely dissolved. Filter using a 0.22μm microporous membrane. The content of toluene insoluble matter was measured to be 0.15%, which meets the requirement of ≤0.2%. TCTNB solution is obtained. S12. Nitrogen gas is introduced into the high-pressure reactor to replace the air. The TCTNB solution is transferred into the high-pressure reactor, 136 mL of deionized water is added, the high-pressure reactor is sealed, and the temperature is increased to 150°C at 5°C / min. S13, via mass flow meter at 4.5 kg / cm³ 2 Ammonia gas was introduced into the high-pressure reactor at a rate of 6.3:1 until the reaction was complete. The reaction pressure was maintained at 1.2 MPa. After the required amount of ammonia gas was introduced, the reactor was cooled to room temperature. The high-pressure reactor was opened, the reaction mixture was poured out, and filtered to obtain 98.7 g of pale yellow crude TATB. Step 2, TATB post-processing, including: S21. Add 2g of crude TATB to 500mL of 50℃ hot water and disperse by ultrasonication to form a uniform suspension; S22. Transfer the suspension to an ultrasonic boiling and washing device, maintain the jacket temperature at 50°C, and use process parameters of ultrasonic frequency 40kHz, ultrasonic power 30W / L, and stirring speed 300rpm to perform ultrasonic-assisted boiling and washing for 5 hours, followed by filtration. S23, after filtration, use 300 mL of acetone and 300 mL of 50°C hot water to wash alternately three times, vacuum drying at 45°C for 4 hours, to obtain low-chlorine TATB crystals with uniform pore structure.

[0024] Example 4 A method for preparing low-chlorine TATB crystals with uniform pore structure, comprising the following steps: Step one, TATB amine synthesis, including: S11, weigh 110g of crude TCTNB into 1000g of toluene, mechanically stir for 40 minutes until completely dissolved, filter using a 0.22μm microporous filter membrane, measure the toluene insoluble content to be 0.15%, meeting the ≤0.2% requirement, to obtain a TCTNB solution; S12, in a high-pressure reaction kettle, replace air with nitrogen, transfer the TCTNB solution into the high-pressure reaction kettle, add 136mL of deionized water, seal the high-pressure reaction kettle, and heat to 150°C at 5°C / min; S13, pass ammonia gas into the high-pressure reaction kettle at a rate of 4.5kg / cm 2 until the reaction is complete, the molar ratio of ammonia to TCTNB is 6.3:1, the reaction pressure is maintained at 1.2MPa, after the required amount of ammonia is passed in, cool to room temperature, open the high-pressure reaction kettle, pour out the reaction mixture, and filter to obtain 98.7g of light yellow crude TATB; Step two, TATB post-treatment, including: S21, add 2g of crude TATB into 500mL of 50°C hot water, disperse with ultrasonic, to form a uniform suspension; S22, transfer the suspension to an ultrasonic cooking and washing device, maintain a 50°C jacket temperature, use process parameters of ultrasonic frequency 40kHz, ultrasonic power 30W / L, stirring speed 300rpm, ultrasonic-assisted cooking and washing for 3 hours, and filter; S23, after filtration, use 300 mL of acetone and 300 mL of 50°C hot water to wash alternately three times, vacuum drying at 45°C for 4 hours, to obtain low-chlorine TATB crystals with uniform pore structure.

[0025] Comparative Example 1 Comparative Example 1 was prepared by a conventional wet ammination method, and the TATB crystals obtained by high-temperature cooking and washing treatment, the specific method comprising: dissolving crude TCTNB (100g) in toluene (1200mL), filtering the obtained solution to remove any toluene insoluble substances (<0.2%); transfer the solution to a reactor, add 100g of water, seal the reactor and heat to 150°C, pass ammonia gas into the reactor at a rate of 4.5kg / cm 2The reactor was cooled to room temperature after the required amount of ammonia was passed in, the reactor was opened, the reaction mixture was poured out, and a yellow solid (crude TATB) was obtained by filtration; the crude TATB was added to 1 L of hot water at 90°C, boiled and washed for 1 hour, filtered, and washed with acetone and hot water at 90°C alternately three times, and dried at 45°C under vacuum for 4 hours to obtain TATB crystals.

[0026] The porosity and chlorine content of the TATB crystals prepared in Examples 1-4 and Comparative Example 1 are shown in Table 1; the pore size distribution of the low-chlorine TATB crystals with uniform pore structure prepared in Example 4 is shown in Figure 1 ; and the pore size distribution of the TATB crystals prepared in Comparative Example 1 is shown in Figure 2 .

[0027] Table 1 As can be seen from Table 1 and Figures 1-2 , compared to Comparative Example 1, the TATB crystals prepared in Examples 1-4 have a uniform pore structure, higher porosity, and lower chlorine content.

[0028] Although embodiments of the present application have been disclosed as above, it is not limited only to the applications listed in the specification and the embodiments, and it can be fully applied to various fields suitable for the present application, and additional modifications can be easily made by those skilled in the art, and thus the present application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A method for preparing low-chlorinated TATB crystals with a uniform porous structure, characterized in that, Includes the following steps: Step 1, TATB amination synthesis, including: S11. Dissolve crude TCTNB in ​​toluene, filter to remove toluene-insoluble matter, and obtain TCTNB solution; S12. Nitrogen gas is introduced to purge the air from the reactor. TCTNB solution is transferred into the reactor, deionized water is added, the reactor is sealed and heated, and then ammonia gas is introduced to carry out the reaction. After the reaction is completed, the reactor is cooled to room temperature and filtered to obtain crude TATB. Step 2, TATB post-processing, including: S21. Add crude TATB to hot water and disperse by ultrasonication to obtain a suspension; S22. The suspension is subjected to ultrasonic-assisted boiling and washing, filtered, washed alternately with acetone and hot water, and dried to obtain low-chlorinated TATB crystals with a uniform porous structure.

2. The method for preparing low-chlorinated TATB crystals with a uniform porous structure as described in claim 1, characterized in that, In S11, the mass ratio of crude TCTNB to toluene is 10~12:

100.

3. The method for preparing a low-chlorinated TATB crystal with a uniform porous structure as described in claim 1, characterized in that, In step S11, a 0.22 μm microporous membrane is used for filtration; the content of toluene-insoluble matter filtered is ≤0.2%.

4. The method for preparing a low-chlorinated TATB crystal with a uniform porous structure as described in claim 1, characterized in that, In S12, the mass ratio of deionized water to crude TCTNB in ​​S11 is 25~27:

21.

5. The method for preparing a low-chlorinated TATB crystal with a uniform porous structure as described in claim 1, characterized in that, In step S12, the heating rate of the sealing heating is 3℃ / min~8℃ / min, and the temperature is raised to 130℃~150℃.

6. The method for preparing a low-chlorinated TATB crystal with a uniform porous structure as described in claim 1, characterized in that, In step S12, the ammonia gas introduction rate is 4 kg / cm³. 2 ~5kg / cm 2 The molar ratio of ammonia to TCTNB is 6~6.5:

1.

7. The method for preparing a low-chlorinated TATB crystal with a uniform porous structure as described in claim 1, characterized in that, In step S21, the temperature of the hot water is 50℃~80℃; the mass ratio of crude TATB to hot water is 1:200~300.

8. The method for preparing a low-chlorinated TATB crystal with a uniform porous structure as described in claim 1, characterized in that, In S22, the specific method of ultrasonic-assisted boiling and washing is as follows: the suspension is transferred to the ultrasonic boiling and washing equipment, and the jacket temperature, ultrasonic frequency, ultrasonic power, and stirring rate are set for boiling and washing for 3 to 5 hours.

9. The method for preparing a low-chlorinated TATB crystal with a uniform porous structure as described in claim 8, characterized in that, The jacket temperature is 50℃~80℃; The ultrasonic frequency is 20kHz~120kHz; The ultrasonic power is 10W / L~40W / L; The stirring speed is 200 rpm to 400 rpm.

10. The method for preparing a low-chlorinated TATB crystal with a uniform porous structure as described in claim 1, characterized in that, In step S22, the drying method includes any one of room temperature drying, vacuum drying, and freeze drying.

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