A stable preparation method for synthesizing lead stephanate of type II by ammonia salt method

Abstract

The present application relates to a kind of stable preparation method of type II basic lead stephanate, belong to detonating explosive, firing charge, pyrotechnics, energetic material technical field.The method described in the present application is prepared by changing reaction raw materials, optimizing synthesis process and hydrothermal reaction, to obtain type II B-LTNR product.The method avoids the generation of type I acicular B-LTNR, not only improves the physical and chemical stability of B-LTNR, reduces mechanical sensitivity, but also significantly improves its dispersibility, mixing and packing density and other application performance.Using the method can ensure the quality and application reliability of the obtained type II B-LTNR product, the obtained product has good flowability, good crystal shape consistency, high yield and other characteristics, and the process is simple and easy to operate, high safety, suitable for industrial production, has good application prospect in detonating explosive, firing charge, pyrotechnics, energetic material and other related technical fields.

Description

[0001] Technical Field: This invention relates to a stable preparation method of type II basic lead styrene, belonging to the technical fields of detonators, firing propellants, pyrotechnic agents, and energetic materials. Background Technology

[0002] Pyrotechnics, as key sensitive components used to achieve special functions such as ignition, detonation, detonation propagation, gas generation, and delay, can rapidly undergo chemical reactions such as combustion and explosion under certain external energy stimulation, releasing energy to achieve certain chemical-physical or mechanical effects. Therefore, they are widely used in various weapon systems, aerospace, and other fields. The most sensitive energetic material initiating explosive in the charge sequence serves as the basic charge for igniting and detonating pyrotechnics. It is the initial energy source and technical key to the pyrotechnics. The stability of its physical and chemical properties has a crucial impact on the safety and reliability of pyrotechnics under harsh environments. High-quality initiating explosives can rapidly and stably trigger subsequent explosion sequences, ensuring that pyrotechnics can reliably perform their functions under various environmental conditions and within predetermined timeframes, reducing the risk of pyrotechnic failure or accidental detonation due to quality issues.

[0003] Basic lead stearate, officially known as basic lead trinitroresorcinol (abbreviated as B-LTNR), is a heavy metal salt of nitrophenol and a single-element initiating explosive widely used in the field of pyrotechnics. It has advantages such as high flame sensitivity, non-corrosiveness, good vacuum thermal stability, and compatibility with various metal materials. However, its initiation ability is relatively weak. It is widely used as an important component in the ignition charge of flame detonators, as well as in needle-piercing charges, non-corrosive igniting charges, and ignition charges of electric detonators. It is one of the most commonly used single-element initiating explosives in my country and has great application value.

[0004] Despite its advantages, B-LTNR exhibits complex crystallization properties, with at least two variable crystal forms existing. Currently, it is classified into Type I and Type II. Type I products are yellow to orange-yellow needle-like discrete crystals, generally appearing as yellow flocculent matter. Type II products are yellowish-brown to brown discrete crystals, generally appearing as relatively uniform yellowish-brown fine granules. Crystal morphology is one of the most important quality indicators for evaluating initiating explosive crystal products, directly determining the physicochemical properties of the initiating explosive crystals, such as bulk density, flowability, solubility, and loading performance. It also affects the explosive performance and safety performance of the initiating explosive. The crystal morphology of the initiating explosive is directly related to its properties, defects, and loading density, thus directly affecting its mechanical sensitivity and application performance. In current B-LTNR synthesis technology, due to the inherent molecular characteristics of the compound and technical limitations in the synthesis process, the synthesized crystals are mostly Type I needle-like products with an apparent density of 0.3–0.5 g / cm³. 3This undesirable condition not only affects the overall quality of B-LTNR products but also brings various potential risks and hazards to their practical application. The products typically exhibit poor flowability and mixing properties, making them unsuitable for loading and difficult to meet technical requirements. Currently, in the actual production process of B-LTNR, methods such as strictly controlling the pH of the reaction medium, adding crystal form control agents or a certain amount of lead stearate seed crystals, and strictly controlling the supersaturation of the reaction solution are commonly used to produce type II B-LTNR (apparent density 1.2–1.6 g / cm³). 3 However, this process is complex and prone to introducing new impurities, which are difficult to resolve and severely affect its purity and quality, thus impacting its application performance. Therefore, it is urgent to adjust the technical route and process of type II B-LTNR to avoid generating type I B-LTNR, achieve stable preparation of type II B-LTNR, and solve the technical difficulties existing in the production and use of B-LTNR products.

[0005] In summary, developing a stable preparation method for type II B-LTNR with good crystal morphology, and obtaining a preparation method for type II B-LTNR with good crystal consistency, few crystal defects, and high safety, is of great significance for the application of B-LTNR in the fields of initiating explosives, detonating explosives, pyrotechnic agents, energetic materials, etc. Summary of the Invention

[0006] This invention addresses the problem of different crystal forms (Type I and Type II) in the synthesis of B-LTNR. By modifying the reactants and using ammonia as the reactant, it avoids the formation of Type I needle-like B-LTNR and provides a stable preparation method for Type II B-LTNR via the ammonium salt method. This method, through changing the reactants, optimizing the synthesis process and hydrothermal reaction, first reacts styracimenic acid with ammonia to generate styracimenic acid, which then reacts with lead nitrate to generate B-LTNR. Excess ammonia is added during this process to ensure the reaction proceeds under weakly alkaline conditions, thus stably preparing the Type II B-LTNR product. This method avoids the formation of Type I needle-like B-LTNR, improving the physical and chemical stability of B-LTNR, reducing its mechanical sensitivity, and significantly enhancing its dispersibility, mixability, and packing density. This method avoids the use of crystal form control agents and seed crystals, which easily introduce foreign impurities. It prepares Type II B-LTNR products using only the system's reactants, resulting in products with good flowability, good crystal form consistency, and high yield. By implementing this invention, the quality and application reliability of the synthesized Type II B-LTNR product can be ensured. The process is simple, easy to implement, and highly safe, making it suitable for industrial production and providing strong support for the development of related technical fields such as detonators, firing propellants, pyrotechnic agents, and energetic materials.

[0007] The objective of this invention is achieved through the following technical solutions.

[0008] A stable preparation method for synthesizing type II B-LTNR via ammonium salt method, the method steps are as follows:

[0009] (1) Preparation of raw material aqueous solution

[0010] Prepare an aqueous solution of ammonium stearate, denoted as ammonium stearate solution; in the ammonium stearate solution, the mass percentage of ammonium stearate is 5% to 25%, and the pH value is between 8 and 12;

[0011] Prepare an aqueous solution of lead nitrate, denoted as lead nitrate solution; in the lead nitrate solution, the mass percentage of lead nitrate is 5% to 30%, and the pH value is between 3.5 and 5.5.

[0012] (2) Combination process

[0013] Using lead nitrate solution or styracimenic acid solution as the base liquid and styracimenic acid solution or lead nitrate solution as the dropping liquid, styracimenic acid solution is added dropwise to lead nitrate solution or lead nitrate solution is added dropwise to styracimenic acid solution over a period of 30–60 min. After the addition is complete, the mixture is stirred in a constant temperature water bath at 70–85 °C for 10–40 min. The mixture is then cooled, filtered, washed, and dried to obtain type II B-LTNR product.

[0014] The molar ratio of ammonium styracinate in the ammonium styracinate solution to lead nitrate in the lead nitrate solution is 1:

[0015] (1.5~2.5), this feed ratio ensures that the molecular formula of the formed B-LTNR is C6H2N4O6Pb.

[0016] In addition, during the preparation of styracimenic acid ammonia solution and lead nitrate solution, the pH value of the solution can be adjusted to the required range by adding dilute nitric acid solution (when the initial pH value of the raw material aqueous solution is higher than the required range) or / and 28% ammonia solution (when the initial pH value of the raw material aqueous solution is lower than the required range).

[0017] Furthermore, in the ammonia solution of stemonate, the mass fraction of ammonia of stemonate is preferably 8% to 20%.

[0018] Furthermore, in the lead nitrate solution, the mass fraction of lead nitrate is preferably 10% to 20%.

[0019] Furthermore, the pH of the entire reaction solution system (i.e., the reaction system formed by the ammonia styraciformis solution and the lead nitrate solution) is 8–11.

[0020] Furthermore, the reaction temperature of the entire reaction system is 70–80°C.

[0021] Furthermore, by adding the ammonia solution of styracimene to the lead nitrate solution dropwise over a period of 30 to 45 minutes, type II B-LTNR can be generated.

[0022] Furthermore, the stirring rate involved in the combination process is 300 r / min to 500 r / min.

[0023] The Type II B-LTNR prepared by the method described in this invention has great application prospects in related technical fields such as initiating explosives, firing explosives, pyrotechnic agents, and energetic materials.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) This invention addresses the problem that B-LTNR synthesis has two crystal forms, type I and type II, due to the molecular characteristics of the substance itself. Due to the limitations of the synthesis process technology, type I B-LTNR is easily generated. The proposed crystal form optimization method achieves the stable preparation of type II B-LTNR products by replacing the reaction raw materials and optimizing the process parameters, thereby significantly improving the crystal form quality of the product.

[0026] (2) The method described in this invention has a simple and easy synthesis route, high safety, high yield of type II B-LTNR product, good flowability, which greatly improves the stability and application performance of the product. It can play a better role in the fields of initiating explosives, firing explosives, pyrotechnic agents, energetic materials, etc., and has a good application prospect. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the process for preparing type II B-LTNR according to the present invention;

[0028] Figure 2 These are physical images and microscope images of the type II B-LTNR prepared according to the present invention;

[0029] Figure 3 These are comparison images of the physical samples and crystal forms of Type I B-LTNR and Type II B-LTNR products; Detailed Implementation

[0030] The present invention is described below with reference to specific embodiments, but the conditions and results described in the implementation do not constitute a limitation on the content and rights of the invention.

[0031] Example 1: Raw materials: Stefanic acid (C6H3N3O8), lead nitrate [Pb(NO3)2], 28% ammonia water (NH3·H2O), deionized water (H2O), dilute nitric acid (HNO3).

[0032] Main instruments and equipment: magnetic stirrer, super constant temperature water bath, graduated cylinder, jacketed beaker, beaker, peristaltic pump, constant temperature drying oven, oil bath, pH meter.

[0033] Step 1: Add the styracitric acid powder to a beaker, add the measured amount of deionized water, and stir to fully suspend the styracitric acid in the deionized water. Slowly add the measured amount of 28% ammonia solution, stirring until the suspended styracitric acid is completely dissolved and thoroughly mixed. Then, under constant temperature water bath stirring, slowly add excess 28% ammonia solution to ensure the reaction medium is weakly alkaline. During this process, use a pH meter to precisely monitor the acid-base changes of the solution. After stirring to ensure the solution is thoroughly mixed, prepare the styracitric acid ammonia solution. Transfer the obtained solution to a beaker as the dropping solution. Place the suction end of the peristaltic pump hose in the beaker for later use. The pH value of the solution should be between 8 and 10, and the mass fraction of styracitric acid ammonia should be 8%.

[0034] Step 2: Add lead nitrate powder to a beaker, add deionized water measured according to the stoichiometric ratio, stir in a constant temperature water bath until all solutes are fully dissolved and mixed evenly, then add 28% ammonia solution to adjust the pH value of the solution. The white precipitate of Pb(OH)2 generated during this process is removed by filtration to obtain a colorless and transparent solution for later use. The pH value of the solution should be between 4 and 5.5, and the mass fraction of lead nitrate is 10%.

[0035] Step 3: Add the 50 mL of the prepared lead nitrate solution to the jacketed beaker reaction reactor, set the stirring speed to 400 r / min, start the super constant temperature water bath, keep the temperature of the reaction system at 70-80℃, and heat the lead nitrate solution to the water bath temperature.

[0036] Step 4: Start the peristaltic pump and slowly add 50 mL of the prepared ammonia stearate solution to the lead nitrate solution over 45 minutes.

[0037] Step 5: After the ammonia solution of styracitonin is added dropwise, the reaction solution is stirred at a constant temperature of 70-80℃ for 30 minutes. Then, the heating is stopped and the reaction system is allowed to cool naturally to room temperature under stirring to generate a yellowish-brown type II B-LTNR product. After filtering to remove the mother liquor, washing the filtered product, and drying, 8.13g of B-LTNR product is obtained, with a yield of 81.3%.

[0038] Example 2: Raw materials: Stefanic acid (C6H3N3O8), lead nitrate [Pb(NO3)2], 28% ammonia water (NH3·H2O), deionized water (H2O), dilute nitric acid (HNO3).

[0039] Main instruments and equipment: magnetic stirrer, super constant temperature water bath, graduated cylinder, jacketed beaker, beaker, peristaltic pump, constant temperature drying oven, oil bath, pH meter.

[0040] Step 1: Add lead nitrate powder to a beaker, add deionized water measured according to the stoichiometric ratio, stir in a constant temperature water bath until all solutes are fully dissolved and mixed evenly, then add 28% ammonia solution to adjust the pH value of the solution. The white precipitate of Pb(OH)2 generated during this process is removed by filtration. Transfer the resulting colorless and transparent solution to a beaker as a dropping solution. Place the suction end of the peristaltic pump hose in the beaker for later use. The pH value of the solution should be between 4 and 5.5, and the mass fraction of lead nitrate is 10%.

[0041] Step Two: Add the styracitric acid powder to a beaker, add the measured amount of deionized water, and stir to fully suspend the styracitric acid in the deionized water. Slowly add the measured amount of 28% ammonia solution, stirring until the suspended styracitric acid is completely dissolved and thoroughly mixed. Then, under constant temperature water bath stirring, slowly add excess 28% ammonia solution to ensure the reaction medium is weakly alkaline. During this process, use a pH meter to precisely monitor the acid-base changes of the solution. After stirring to ensure the solution is thoroughly mixed, prepare the styracitric acid ammonia solution. The pH value of the solution should be between 8 and 10, and the mass fraction of styracitric acid ammonia should be 8%.

[0042] Step 3: Add 50 mL of the prepared ammonia stearate solution to the jacketed beaker reaction reactor, set the stirring speed to 400 r / min, start the super constant temperature water bath, keep the temperature of the reaction system at 70-80℃, and heat the bottom liquid to the water bath temperature.

[0043] Step 4: Start the peristaltic pump and slowly add 50 mL of the prepared lead nitrate solution dropwise to the ammonia stevia solution over 45 minutes.

[0044] Step 5: After the lead nitrate solution has been added dropwise, the reaction solution is stirred at a constant temperature of 70-80℃ for 30 minutes. Then, the heating is stopped, and the reaction system is allowed to cool naturally to room temperature under stirring to generate an orange-red type II B-LTNR product. The mother liquor is then removed by filtration, the filtered product is washed, and dried to obtain 8.34g of B-LTNR product, with a yield of 83.4%.

[0045] Example 3: Raw materials: Stefanic acid (C6H3N3O8), lead nitrate [Pb(NO3)2], 28% ammonia water (NH3·H2O), deionized water (H2O), dilute nitric acid (HNO3).

[0046] Main instruments and equipment: magnetic stirrer, super constant temperature water bath, graduated cylinder, jacketed beaker, beaker, peristaltic pump, constant temperature drying oven, oil bath, pH meter.

[0047] Step 1: Add the styracitric acid powder to a beaker, add the measured amount of deionized water, and stir to fully suspend the styracitric acid in the deionized water. Slowly add the measured amount of 28% ammonia solution, stirring until the suspended styracitric acid is completely dissolved and thoroughly mixed. Then, under constant temperature water bath stirring, slowly add excess 28% ammonia solution to ensure the reaction medium is weakly alkaline. During this process, use a pH meter to precisely monitor the acid-base changes of the solution. After stirring to ensure the solution is thoroughly mixed, prepare the styracitric acid ammonia solution. Transfer the obtained solution to a beaker as the dropping solution. Place the suction end of the peristaltic pump hose in the beaker for later use. The pH value of the solution should be between 8 and 10, and the mass fraction of styracitric acid ammonia should be 8%.

[0048] Step 2: Add lead nitrate powder to a beaker, add deionized water measured according to the stoichiometric ratio, stir in a constant temperature water bath until all solutes are fully dissolved and mixed evenly, then add 28% ammonia solution to adjust the pH value of the solution. The white precipitate of Pb(OH)2 generated during this process is removed by filtration to obtain a colorless and transparent solution for later use. The pH value of the solution should be between 4 and 5.5, and the mass fraction of lead nitrate is 10%.

[0049] Step 4: Add 50 mL of the prepared lead nitrate solution to the jacketed beaker reaction reactor, set the stirring speed to 500 r / min, start the super constant temperature water bath, keep the temperature of the reaction system at 70-80℃, and heat the lead nitrate solution to the water bath temperature.

[0050] Step 5: Start the peristaltic pump and slowly add 50 mL of the prepared ammonia stearate solution to the lead nitrate solution over 1 hour.

[0051] Step 6: After the ammonia solution of styracitonin has been added dropwise, the reaction solution is stirred for 10 minutes at a constant temperature of 70-80℃. Then, the heating is stopped and the reaction system is allowed to cool naturally to room temperature under stirring to generate a yellowish-brown type II B-LTNR product. After filtering to remove the mother liquor, washing the filtered product, and drying, 8.51g of B-LTNR product is obtained, with a yield of 85.1%.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stable process for the synthesis of B-LTNR type II by the ammonium salt method, characterized in that: The method steps are as follows: (1) Preparation of raw material aqueous solution: prepare an aqueous solution of steffimic acid ammonia, denoted as steffimic acid ammonia solution; in the steffimic acid ammonia solution, the mass percentage of steffimic acid ammonia is 5% to 25%, and the pH value is between 8 and 12; prepare an aqueous solution of lead nitrate, denoted as lead nitrate solution; in the lead nitrate solution, the mass percentage of lead nitrate is 5% to 30%, and the pH value is between 3.5 and 5.5; The specific preparation method of the steffimic acid ammonia solution is as follows: add steffimic acid powder into a beaker, add deionized water taken in a metered amount, stir to fully suspend the steffimic acid in the deionized water, slowly add 28% ammonia water solution taken in a metered amount, stir to fully dissolve and mix the suspended steffimic acid, then slowly add excess 28% ammonia water solution under constant temperature water bath stirring to ensure the weak alkalinity of the reaction medium, monitor the acid-base change of the solution with a pH meter during the process, stir to fully mix the solution, then prepare the steffimic acid ammonia solution, and transfer the obtained solution to the beaker as a dropping liquid, and place the suction end of the peristaltic pump hose in the beaker for standby; The specific preparation method of the lead nitrate aqueous solution is as follows: add lead nitrate powder into a beaker, add deionized water taken in a metered amount, fully dissolve and mix all solutes under constant temperature water bath stirring, then add 28% ammonia water solution to adjust the pH value of the solution, remove the white Pb(OH)2 precipitate generated during the process by filtration, and obtain a colorless transparent solution for standby; (2) The combination process is to take the lead nitrate solution or the steffimic acid ammonia solution as the bottom liquid, and the steffimic acid ammonia solution or the lead nitrate solution as the dropping liquid, drop the steffimic acid ammonia solution into the lead nitrate solution or drop the lead nitrate solution into the steffimic acid ammonia solution, the dropping time is 30 to 60 min, after the dropping is completed, stir under constant temperature water bath at 70 to 85℃ for 10 to 40 min, cool, filter, wash, dry, and obtain the type II B-LTNR product.

2. The method of claim 1, wherein: Steffimic acid ammonia is synthesized by using ammonia water as a raw material, and the steffimic acid ammonia reacts with lead nitrate to generate type II basic steffimic acid lead product.

3. The method of claim 1, wherein: The temperature of the reaction system formed by the steffimic acid ammonia solution and the lead nitrate solution is controlled at 70 to 80℃, the stirring rate is controlled at 300 to 500 r / min, and the dropping time is controlled at 30 to 45 min.

4. The method of claim 1, wherein: In the steffimic acid ammonia solution, the mass percentage of steffimic acid ammonia is 8% to 20%.

5. The method of claim 1, wherein: In the lead nitrate solution, the mass percentage of lead nitrate is 10% to 20%.

6. The method of claim 1, wherein: The molar ratio of steffimic acid ammonia in the steffimic acid ammonia solution to lead nitrate in the lead nitrate solution is 1:(1.5 to 2.5).

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