Stable preparation method for synthesizing NTO basic lead salt through ammonia salt method
Through ammonia salt method in an alkaline environment to synthesize NTO alkaline lead salt, it solves the problem of poor crystal and product unstable products in its synthesis process, realizes the product stability and excellent crystal, and enhances its in -fire speed catalyst, which is catalyst, and it is catalytic, and its in combustion speed catalyst, which is catalytic, The application performance of solid propellant and energy -containing materials.
Patent Information
- Application Number
- CN202411578906.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-01-24
AI Technical Summary
During the synthesis process, NTO basic lead salt has problems such as poor crystal shape, easy deposition, and unstable product, which affects its application in the fields of combustion speed catalysts, solid propellants, and energy-containing materials.
The ammonia salt method is used to generate the intermediate NTONH4 through NTO and ammonia water reactions, and in the alkaline environment, the NTO loses the electrons to generate the NTO di -valent anion, and then reacts with lead nitrate. Alkaline lead salt, control the reaction conditions to ensure the stability and excellent crystal of the product.
Realized the stability of NTO alkaline lead salt, the product has good physical and chemical stability, low mechanical sensitivity, excellent dispersability and loading density, suitable for industrial production, which enhances its catalyst, solid propellant, contained Application performance in the field of material materials.
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Figure CN119350260A_ABST
Abstract
Description
[0001] Technical field: The present invention relates to a stable preparation method of NTO basic lead salt, which comprises reacting excess ammonia water with 3-nitro-1,2,4-triazole-5-one (NTO) to synthesize NTO diammonium salt, and then reacting with lead nitrate. By controlling the reaction conditions, a neutralization reaction and a double decomposition reaction are carried out to obtain a stable NTO basic lead salt product in a "one-pot method", belonging to the technical field of burning rate catalysts, solid propellants, and energetic materials. Background Art
[0002] With the rapid development of military technology, in order to meet the needs of future long-range operations, various military powers are competing to develop various weapon systems and equipment with high-energy propulsion units such as missiles that can fly far, hit accurately and at high speeds. Therefore, solid propellants are required to have high burning rate, high energy and high thrust. As a type of energetic material that releases energy quickly when burning and produces a large amount of high-temperature gas, solid propellants are the core power source of solid engines of various weapon systems such as rockets and missiles, and directly determine the combat effectiveness and survivability of missile weapon systems. As an important indicator for its performance evaluation, the burning rate has strict requirements on the amount of propellant gas generated and the thrust generated by the engine. Solid propellants need to have a wide burning rate adjustment range and a low pressure index. Adding a burning rate catalyst is currently the most widely used and commonly used method to increase the burning rate of solid propellants, and it has always been a hot topic in the field of solid propellant research.
[0003] Burning rate catalysts can reduce the pressure index of solid propellants and improve the combustion stability of solid propellants. During the combustion process, burning rate catalysts can reduce combustion fluctuations, reduce the generation and emission of combustion products, enable platform combustion or wheat-spreading effect within a specific pressure range, and reduce damage to the internal structure of the engine. As an energetic complex burning rate catalyst, NTO lead salt series energetic materials have the advantages of high energy, high catalytic activity, and good compatibility. They can increase the energy of propellants, inhibit unstable combustion, and achieve the dual effects of increasing the burning rate and reducing the pressure index, meeting the solid propellant's demand for regulating the burning rate.
[0004] The NTO lead salt series of energetic materials mainly include NTO acid lead salt (abbreviated as PNTO), NTO lead salt (abbreviated as NP), and NTO basic lead salt. They have been widely used in the formulation of various types of solid propellants in the field of solid propellants and have great application value. However, PNTO has a certain acidity because the NTO anion contains acidic protons, which restricts its application in propellants; due to the molecular characteristics of NP itself and the technical limitations in the synthesis process, the crystals obtained by synthesis mostly show poor crystal forms such as needles, which not only affects the overall quality of NP products, but also has problems such as uneven particle size distribution, poor fluidity, and high sensitivity, which brings a variety of potential risks and hazards to its practical application. As an energetic complex of the NTO lead salt series, NTO basic lead salt has a theoretical molecular formula of C2H2N4O2(OPbOH)2, and the theoretical lead content can reach 72%. Compared with NP and PNTO, it has a higher lead content and can achieve a better catalytic effect. The synthesized NTO basic lead salt product is an orange-red to brown powder product as a whole, and the crystal shape is short columnar crystals. NTO basic lead salt products have the advantages of good fluidity, uniform particle size distribution, high bulk density, high lead content, good thermal stability and moderate acidity and alkalinity, and can be used as an energetic burning rate catalyst to replace NP in solid propellants. However, the synthesis of NTO basic lead salt has problems such as unstable synthesis conditions, the product is easy to deposit on the bottom of the kettle to form a scab, and the crystal shape is poor, which seriously affects the practical application of NTO basic lead salt. Therefore, it is urgent to develop a stable preparation method for NTO basic lead salt to solve the technical problems existing in the production and use of NTO basic lead salt products.
[0005] In summary, developing a stable preparation method for NTO basic lead salt with good crystal form, and obtaining a stable preparation method for NTO basic lead salt with good crystal consistency, good fluidity, few crystal defects and high safety is of great significance for the application of NTO basic lead salt in the fields of burning rate catalysts, solid propellants and energetic materials. Summary of the invention
[0006] The present invention is committed to solving the problem of the synthesis and preparation of NTO basic lead salt. By drawing on the synthesis path of NP products and referring to the safety hazards such as the easy formation of needle-shaped crystals by NP due to the strong alkaline environment during its synthesis, weak alkaline ammonia water is used instead of strong alkaline sodium hydroxide as a reaction raw material on the basis of the traditional sodium salt method, the alkaline environment of the entire reaction system is weakened to avoid the formation of needle-shaped crystals, and NTO and lead nitrate are used as reaction raw materials. The NTO basic lead salt is synthesized by neutralization and double decomposition reaction "one pot method", and a stable preparation method for synthesizing NTO basic lead salt by ammonia salt method is provided. The method precisely controls the reaction conditions, firstly generates an intermediate NTONH4 by reacting NTO with ammonia water, and then further adds ammonia water to create an alkaline environment so that NTO loses two electrons to generate NTO divalent anions, generating NTO(NH4)2, and after the solid suspension is completely dissolved, excess ammonia water is added to ensure a strong alkaline environment, and then reacts with lead nitrate to generate NTO basic lead salt, thereby stably preparing a NTO basic lead salt product with excellent crystal form. The method effectively synthesizes the NTO basic lead salt product, avoids the generation of needle-shaped crystals, and the NTO basic lead salt product has good physical and chemical stability, low mechanical sensitivity, and excellent application performances such as dispersibility and packing density. The NTO basic lead salt product prepared by the method has good dispersibility, narrow particle size distribution range, and high yield; through the implementation of the present invention, the quality and application reliability of the synthesized NTO basic lead salt product can be ensured, the process is simple and easy, and the safety is high, which is suitable for industrial production, and provides strong support for the development of related technical fields such as burning rate catalysts, solid propellants, and energetic materials.
[0007] The objectives of the present invention are achieved through the following technical solutions.
[0008] A stable preparation method for synthesizing NTO basic lead salt by an ammonium salt method, the method steps are as follows:
[0009] (1) Preparation of raw material aqueous solution
[0010] Prepare an aqueous solution of NTO(NH4)2, recorded as NTO(NH4)2 solution; in the NTO(NH4)2 solution, the mass percentage of NTO(NH4)2 is 4% to 20%, and the pH value is between 9 and 12.
[0011] An aqueous solution of lead nitrate is prepared, which is referred to 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) Chemical Combination Process
[0013] With lead nitrate solution or NTO(NH4)2 solution as base liquid and NTO(NH4)2 solution or lead nitrate solution as dropping liquid, in a constant temperature water bath of 60℃~85℃ and a rotation speed of 100r / min~500r / min, NTO(NH4)2 solution is dropped into lead nitrate solution or lead nitrate solution is dropped into NTO(NH4)2 solution, the dropping time is 20~80min, after the dropping is completed, the reaction conditions are kept unchanged, the reaction is kept warm for 10min~30min, and the product of orange-red to brown NTO basic lead salt is obtained.
[0014] The molar ratio of NTO(NH4)2 in the NTO(NH4)2 solution to lead nitrate in the lead nitrate solution is 1:(1.95-2.05) to ensure that the molecular formula of the formed NTO basic lead salt is C2H4N4O6Pb2.
[0015] In addition, during the preparation of NTO(NH4)2 solution and lead nitrate solution, the pH value of the solution is adjusted to the required range by adding dilute nitric acid solution (when the initial pH value of the raw aqueous solution is higher than the required range) or / and 28% ammonia solution (when the initial pH value of the raw aqueous solution is lower than the required range) to the solution.
[0016] Furthermore, in the NTO(NH4)2 solution, the mass fraction of NTO(NH4)2 is preferably 5% to 15%.
[0017] Furthermore, in the lead nitrate solution, the mass fraction of lead nitrate is preferably 10% to 20%.
[0018] Furthermore, the pH value of the entire reaction solution system (ie, the reaction system formed by the NTO(NH4)2 solution and the lead nitrate solution) is 8-10.
[0019] Furthermore, the reaction temperature of the entire reaction system is 65-80°C.
[0020] Furthermore, NTO(NH4)2 solution is added dropwise to the lead nitrate solution within 20 to 45 minutes to react and generate NTO basic lead salt.
[0021] Furthermore, the stirring rate involved in the compounding process is 300 r / min to 500 r / min.
[0022] The NTO basic lead salt prepared by the method of the present invention has good application prospects in relevant technical fields such as energetic materials, burning rate catalysts, solid propellants, etc.
[0023] The beneficial effects of the present invention are as follows:
[0024] (1) The present invention designs a synthetic route for NTO basic lead salt, and uses NTO, ammonia water and lead nitrate as reaction raw materials to prepare NTO basic lead salt product through a neutralization reaction and a double decomposition reaction in a "one-pot method". In view of the problem of needle-shaped and other undesirable crystal forms that may be caused by the molecular characteristics of the substance itself and the strong alkaline environment in the reaction system during the synthesis of the NTO basic lead salt product, the stable preparation of the NTO basic lead salt product is achieved by adjusting the reaction route and optimizing the process parameters, thereby significantly improving the crystal quality of the product.
[0025] (2) The method of the present invention has a simple and easy synthesis route, high safety, high yield of NTO basic lead salt product, good fluidity, greatly improved product stability and application performance, can play a better role in the fields of burning rate catalysts, solid propellants, energetic materials, etc., and has a good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a schematic diagram of the process of preparing NTO basic lead salt according to the present invention;
[0027] Figure 2 It is a physical picture and a microscope picture of the NTO basic lead salt product prepared by the present invention;
[0028] Figure 3 It is a physical comparison diagram of NTO basic lead salt products in different states prepared by the present invention and NP. DETAILED DESCRIPTION
[0029] The present invention is described below in conjunction with specific embodiments, but the conditions and results described in the implementation do not limit the content and rights of the invention.
[0030] Example 1: Raw materials: NTO (C2H2N4O4), lead nitrate [Pb(NO3)2], 28% ammonia water (NH3·H2O), deionized water (H2O), dilute nitric acid (HNO3).
[0031] Main instruments and equipment: magnetic stirrer, super constant temperature water bath, measuring cylinder, jacketed beaker, beaker, peristaltic pump, constant temperature drying oven, oil bath pot, pH meter.
[0032] Step 1: Add NTO powder into a beaker, add deionized water measured according to the stoichiometric ratio, stir to fully suspend NTO in the deionized water, slowly add 28% ammonia solution measured according to the stoichiometric ratio, stir to fully dissolve the suspended NTO and mix well to prepare NTONH4 solution.
[0033] Step 2: Use the NTONH4 solution obtained in step 1 as the base solution, slowly add an excess of 28% ammonia solution under stirring in a constant temperature water bath, use a pH meter to accurately monitor the acid-base changes of the solution, and use the pH value of the solution as a criterion to determine the end point of adding 28% ammonia solution. Stir the solution to make it fully mixed and uniform, and then configure it into NTO(NH4)2 solution. Transfer the resulting solution to a beaker as a dropper, place the suction end of the peristaltic pump hose in the beaker for standby use, and the pH value of the solution can be between 9 and 11; the mass fraction of NTO(NH4)2 is 8%.
[0034] Step 3: Add lead nitrate powder into a beaker, add deionized water according to the stoichiometric ratio, stir in a constant temperature water bath to fully dissolve all the solutes and mix them evenly, then add 28% ammonia solution to adjust the pH value of the solution. The white precipitate of Pb(OH)2 produced during the process is removed by filtration to obtain a colorless and transparent solution for use. The pH value of the solution can be between 4 and 5, and the mass fraction of lead nitrate is 10%.
[0035] Step 4: Add 50 mL of the prepared lead nitrate solution into the jacketed beaker reactor, set the stirring rate to 400 r / min, start the super constant temperature water bath, keep the temperature of the chemical system at 75°C to 80°C, and heat the lead nitrate solution to the water bath temperature.
[0036] Step 5: Start the peristaltic pump and slowly add 50 mL of the prepared NTO(NH4)2 solution into the lead nitrate solution within 30 minutes.
[0037] Step 6: After the addition of NTO (NH4) 2 solution is completed, the reaction solution is stirred and reacted at a constant temperature of 75 ° C ~ 80 ° C for 20 minutes, then the heating is stopped, and the reaction system is naturally cooled to room temperature under stirring to generate an orange-red NTO basic lead salt product. The mother liquor is then filtered out, the filtered product is washed, and dried to obtain 8.59g of NTO basic lead salt product, with a yield of 85.9% and a lead content of 71.9%.
[0038] Example 2: Raw materials: NTO (C2H2N4O4), 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, measuring cylinder, jacketed beaker, beaker, peristaltic pump, constant temperature drying oven, oil bath pot, pH meter.
[0040] Step 1: Add lead nitrate powder into a beaker, add deionized water according to the stoichiometric ratio, stir in a constant temperature water bath to fully dissolve all the solutes and mix them evenly, then add 28% ammonia solution to adjust the pH value of the solution. The white precipitate of Pb(OH)2 produced during the process is removed by filtration, and the obtained colorless transparent solution is transferred to a beaker as a dropping liquid. The suction end of the peristaltic pump hose is placed in the beaker for standby use. The pH value of the solution can be between 4 and 5, and the mass fraction of lead nitrate is 10%.
[0041] Step 2: Add NTO powder into a beaker, add deionized water measured according to the stoichiometric ratio, stir to fully suspend NTO in the deionized water, slowly add 28% ammonia solution measured according to the stoichiometric ratio, stir to fully dissolve the suspended NTO and mix well to prepare NTONH4 solution.
[0042] Step 3: Use the NTONH4 solution obtained in step 2 as the base solution, slowly add an excess of 28% ammonia solution under stirring in a constant temperature water bath, use a pH meter to accurately monitor the acid-base changes of the solution, and use the pH value of the solution as a criterion to determine the end point of adding 28% ammonia solution. Stir the solution to make it fully mixed and uniform, and then prepare it into NTO(NH4)2 solution. The pH value of the solution can be between 9 and 11; the mass fraction of NTO(NH4)2 is 8%.
[0043] Step 4: Add 50 mL of the prepared NTO (NH4) 2 solution into the jacketed beaker reactor, set the stirring rate to 400 r / min, start the super constant temperature water bath, keep the temperature of the chemical system at 70°C to 75°C, and heat the bottom liquid to the water bath temperature.
[0044] Step 5: Start the peristaltic pump and slowly add 50 mL of the prepared lead nitrate solution into the NTO(NH4)2 solution within 30 minutes.
[0045] Step 6: After the lead nitrate solution is added dropwise, the reaction solution is stirred and reacted at a constant temperature of 70°C to 75°C for 20 minutes, and then the heating is stopped. The reaction system is naturally cooled to room temperature under stirring to generate a brick-red NTO basic lead salt product. The mother liquor is then filtered out, the filtered product is washed, and dried to obtain 8.72 g of NTO basic lead salt product, with a yield of 87.2% and a lead content of 72.1%.
[0046] Example 3: Raw materials: NTO (C2H2N4O4), lead nitrate [Pb(NO3)2], 28% ammonia water (NH3·H2O), deionized water (H2O), dilute nitric acid (HNO3).
[0047] Main instruments and equipment: magnetic stirrer, super constant temperature water bath, measuring cylinder, jacketed beaker, beaker, peristaltic pump, constant temperature drying oven, oil bath pot, pH meter.
[0048] Step 1: Add NTO powder into a beaker, add deionized water measured according to the stoichiometric ratio, stir to fully suspend NTO in the deionized water, slowly add 28% ammonia solution measured according to the stoichiometric ratio, stir to fully dissolve the suspended NTO and mix well to prepare NTONH4 solution.
[0049] Step 2: Use the NTONH4 solution obtained in step 1 as the base solution, slowly add an excess of 28% ammonia solution under stirring in a constant temperature water bath, use a pH meter to accurately monitor the acid-base changes of the solution, and use the pH value of the solution as a criterion to determine the end point of adding 28% ammonia solution. Stir the solution to make it fully mixed and uniform, and then configure it into NTO(NH4)2 solution. Transfer the resulting solution to a beaker as a dropper, place the suction end of the peristaltic pump hose in the beaker for standby use, and the pH value of the solution can be between 9 and 11; the mass fraction of NTO(NH4)2 is 8%.
[0050] Step 3: Add lead nitrate powder into a beaker, add deionized water according to the stoichiometric ratio, stir in a constant temperature water bath to fully dissolve all the solutes and mix them evenly, then add 28% ammonia solution to adjust the pH value of the solution. The white precipitate of Pb(OH)2 produced during the process is removed by filtration to obtain a colorless and transparent solution for use. The pH value of the solution can be between 4 and 5.5, and the mass fraction of lead nitrate is 10%.
[0051] Step 4: Add 50 mL of the prepared lead nitrate solution into the jacketed beaker reactor, set the stirring rate to 500 r / min, start the super constant temperature water bath, keep the temperature of the chemical system at 65°C to 70°C, and heat the lead nitrate solution to the water bath temperature.
[0052] Step 5: Start the peristaltic pump and slowly add 50 mL of the prepared NTO(NH4)2 solution into the lead nitrate solution within 1 h.
[0053] Step 6: After the addition of NTO (NH4) 2 solution is completed, the reaction solution is stirred and reacted at a constant temperature of 65 ° C ~ 70 ° C for 30 minutes, then the heating is stopped, and the reaction system is naturally cooled to room temperature under stirring to generate an orange-red NTO basic lead salt product. The mother liquor is then filtered out, the filtered product is washed, and dried to obtain 9.12g of NTO basic lead salt product, with a yield of 91.2% and a lead content of 72.0%.
[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A stable preparation method for synthesizing NTO basic lead salt by ammonium salt method, characterized in that: The method steps are as follows: (1) Preparation of raw material aqueous solution An aqueous solution of NTO(NH4)2 is prepared, which is recorded as NTO(NH4)2 solution; in the NTO(NH4)2 solution, the mass percentage of NTO(NH4)2 is 4% to 20%, and the pH value is between 9 and 12; an aqueous solution of lead nitrate is prepared, which is recorded 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. (2) Chemical Combination Process With lead nitrate solution or NTO(NH4)2 solution as base liquid and NTO(NH4)2 solution or lead nitrate solution as dropping liquid, in a constant temperature water bath of 60℃~85℃ and a rotation speed of 100r / min~500r / min, NTO(NH4)2 solution is added dropwise to lead nitrate solution or lead nitrate solution is added dropwise to NTO(NH4)2 solution, the dropping time is 20~80min, after the dropping is completed, the reaction conditions are kept unchanged, the temperature is kept for 10min~30min, and the product of NTO basic lead salt of orange red to brown is obtained after cooling, filtering, washing and drying. The molar ratio of NTO(NH4)2 in NTO(NH4)2 solution and lead nitrate in lead nitrate solution is 1:(1.95~2.05).
2. The method according to claim 1, characterized in that: Ammonia water is used as a reaction raw material to synthesize NTO (NH4) 2, which reacts with lead nitrate to generate NTO basic lead salt product.
3. The method according to claim 1, characterized in that: With lead nitrate solution or NTO(NH4)2 solution as base solution and NTO(NH4)2 solution or lead nitrate solution as dropping solution, NTO(NH4)2 solution is added dropwise into lead nitrate solution or lead nitrate solution is added dropwise into NTO(NH4)2 solution to react and generate NTO basic lead salt product.
4. The method according to claim 1, characterized in that: The temperature of the reaction system is controlled at 60° C. to 85° C., the pH value of the reaction system is controlled at 8 to 10, the stirring rate is controlled at 100 r / min to 500 r / min, and the dropping time is controlled at 20 min to 80 min.
5. The method according to claim 1, characterized in that: In the NTO(NH4)2 solution, the mass fraction of NTO(NH4)2 is 4% to 20%, and the pH value is between 9 and 12; in the lead nitrate solution, the mass fraction of lead nitrate is 5% to 30%, and the pH value is between 3.5 and 5.
5.
6. The method according to claim 1, characterized in that: The molar ratio of NTO(NH4)2 in the NTO(NH4)2 solution to lead nitrate in the lead nitrate solution is 1:(1.95-2.05).
7. A use of the NTO basic lead salt prepared according to claims 1-6, characterized in that: The NTO basic lead salt is used as a burning rate catalyst and ignition powder.