Reso bismuth octoate combustion catalyst and preparation method thereof

Abstract

The invention relates to the technical field of combustion catalysts, in particular to a bismuth resorcinate combustion catalyst and a preparation method thereof.The preparation method comprises the steps that resorcinic acid is dissolved into a sodium resorcinate solution with an alkaline sodium-containing compound solution, and then the sodium resorcinate solution and a bismuth nitrate solution are heated and then conveyed to an ultrasonic mixing reactor; and carrying out aging, filtering, washing and vacuum drying on the bismuth resorcinate precipitate so as to obtain the combustion catalyst. Reacting liquid generates bismuth resorcinate precipitate under the synergistic effect of screen mesh macromixing and ultrasonic micromixing in the mixer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of combustion catalysts, in particular to a bismuth resorcylate combustion catalyst and a preparation method thereof. BACKGROUND

[0002] Lead compounds are the most widely used combustion catalysts in solid propellants. The addition of lead compounds to double-base propellants can significantly change the burning rate of double-base propellants, resulting in super-speed, platform, and MESA combustion behaviors. Due to the high toxicity of lead compounds, they are prone to leak or diffuse into the environment during production, transportation, and use, posing potential risks to the ecological environment and human health. Lead compounds are a key pollution source monitored by environmental protection departments. Bismuth compounds and lead compounds have similar effects on the catalytic combustion of double-base propellants. Bismuth compounds and copper salts have a good synergistic effect in the catalytic combustion process of double-base propellants, which not only increases the burning rate but also reduces the pressure index. Bismuth compounds are widely used in the medical field due to their antidiarrheal and gastrointestinal dyspepsia treatment effects. To reduce the harm of lead compounds to the human body and the environment, bismuth compounds, as an ecologically safe green combustion catalyst, have good application prospects for replacing highly toxic lead compounds.

[0003] Combustion catalysts with fine particle size and uniform distribution have better dispersibility and compatibility in double-base propellant matrices, which can solve the problem of large particle combustion catalysts acting as yield points and stress concentration points in the matrix, but the high shear force during the processing and molding of the propellant column can easily expose the surface of the catalyst, causing interface defects and affecting the performance. SUMMARY

[0004] The present application aims to provide a bismuth resorcylate combustion catalyst and a preparation method thereof, solving the technical problem that there are no non-lead catalysts used in solid propellants in the prior art.

[0005] The present application discloses a preparation method of a bismuth resorcylate combustion catalyst. First, resorcylate acid is dissolved into a sodium resorcylate solution using an alkaline sodium compound solution. Then, the sodium resorcylate solution and a bismuth nitrate solution are heated and delivered to an ultrasonic mixing reactor to generate bismuth resorcylate precipitate. After aging, filtering, washing, and vacuum drying, the bismuth resorcylate precipitate becomes the combustion catalyst.

[0006] Working principle: The reaction mechanism of bismuth resorcylate preparation is as follows: (1) (2) The reaction solution is subjected to macroscopic mixing on a wire mesh and ultrasonic micro-mixing in the mixer to generate bismuth resorcylate precipitate.

[0007] The specific surface area and active site distribution of the narrow-distribution combustion catalyst particles are more uniform, the narrow-distribution particles are more uniformly contacted with the double-base matrix (nitrocellulose / nitroglycerin), the catalytic decomposition reaction is more efficient, the fluctuation of the local combustion rate can be significantly reduced, the burning rate-pressure curve of the propellant is smoother, the sudden increase in the burning rate caused by coarse particles or the decrease in the burning rate caused by the agglomeration of fine particles is avoided, the platform combustion range is widened, the pressure sensitivity is reduced, and the propellant can maintain stable combustion in a wide pressure range.

[0008] The ultrasonic mixing reactor has good micro-mixing performance, can control the particle size and distribution of the reaction precipitate in liquid phase reaction precipitation, and is helpful to the low-cost large-scale preparation of the narrow-distribution catalyst. The burning rate catalyst with narrow particle size distribution significantly optimizes the comprehensive performance of the double-base propellant by improving the combustion uniformity, mechanical reliability and process reproducibility, and is suitable for high-precision aerospace or weapon systems.

[0009] Further, the ultrasonic mixing reactor.

[0010] Further, the alkaline sodium-containing compound solution is a sodium bicarbonate solution or a sodium hydroxide solution.

[0011] Further, the mass ratio of the sodium hydroxide solution to the resorcylic acid is 1.0:(1.0-1.5), and the control reaction end point PH value is 7-8.

[0012] Further, the mass ratio of the sodium resorcylate solution to the bismuth nitrate solution is 1.0:(1.0-1.8).

[0013] Further, the sodium resorcylate solution and the bismuth nitrate solution are heated to 50-75 DEG C.

[0014] Further, the aging is aging at 70 DEG C for 2-5 hours.

[0015] Further, the vacuum drying temperature is 80-95 DEG C.

[0016] A bismuth resorcylate combustion catalyst is prepared by using the above method.

[0017] Further, the molecular formula of the combustion catalyst is BiC7H5O5.

[0018] Further, the particle size distribution of the combustion catalyst is narrow.

[0019] Further, the combustion catalyst has 90-95% of the particles in the range of 375-480 nm.

[0020] Further, the combustion catalyst has 100% of the particles below 480 nm.

[0021] Further, the combustion catalyst has 3-5% of particles below 375nm.

[0022] Compared with the prior art, the present application has the beneficial effects that: 1. The ultrasonic mixing reactor provides a good macroscopic mixing and microscopic mixing environment for the reaction process of the bismuth resorcylate combustion catalyst, and the prepared bismuth resorcylate has uniform and small morphology and narrow particle size distribution, can realize good compatibility with the matrix of the double-base propellant, improves the uniformity of the propellant grain, promotes the decomposition speed of the double-base propellant, shortens the time required for decomposition, and at the same time, promotes the decomposition reaction of the double-base propellant to be more complete, significantly increases the decomposition heat, and is beneficial to improving the combustion efficiency of the double-base propellant; the bismuth resorcylate as a low-toxicity, low-smoke, and ecologically safe green combustion catalyst has good application prospect in replacing the lead compound with high toxicity; 2. The narrow-distribution bismuth resorcylate can accelerate the decomposition speed of the absorption medicine, shorten the time required for decomposition, and at the same time, promote the decomposition reaction of the absorption medicine to be more complete, significantly increase the decomposition heat, and be beneficial to improving the combustion efficiency of the double-base propellant; 3. Compared with the conventional bismuth resorcylate, the narrow-distribution bismuth resorcylate has a 3-fold increase in the burning rate at 4-6MPa, a 2-fold increase in the burning rate at 8-12MPa, and a 1.5-fold increase in the burning rate at 14-20MPa, and the burning rate pressure index is reduced from 0.96 to 0.38 in the pressure range of 4-20MPa. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only represent some embodiments of the present application, and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Figure 1 The IR spectrum of the bismuth resorcylate of the present application and Example 1.

[0025] Figure 2 The SEM of the bismuth resorcylate sample of Example 1 of the present application.

[0026] Figure 3 The particle size distribution of the bismuth resorcylate sample of Example 1 of the present application.

[0027] Figure 4 The TG diagram of the bismuth resorcylate sample of Example 1 of the present application.

[0028] Figure 5 The XRD spectrum of the bismuth resorcylate sample of Example 1 of the present application and the thermal gravimetric residue.

[0029] Figure 6 Catalytic thermal decomposition DSC curves of the inventive NC+NG+Example 1 sample, NC+NG, NC+NG+Comparative Example 1 sample.

[0030] Figure 7 Catalytic combustion rate curves of the inventive Example 1, Comparative Example 1 and no combustion catalyst added. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the present application.

[0032] Example 1 A bismuth raxofelodinate combustion catalyst and a preparation method thereof are disclosed in this embodiment, which comprises the following steps: First, dissolve raxofelodinic acid into a sodium raxofelodinate solution with a sodium hydroxide solution, and heat the bismuth nitrate solution to 70℃, respectively, place them in a raw material tank, and use a metering pump to deliver the two solutions to an ultrasonic mixing reactor at a mass ratio of 1:1.05. The reaction liquid is generated into bismuth raxofelodinate precipitate under the synergistic action of wire mesh macro-mixing and ultrasonic micro-mixing in the mixer. The reactants are aged at 70℃ for 5h, filtered, washed, and vacuum dried at 95℃ to obtain bismuth raxofelodinate, which is marked as NPS.

[0033] Example 2 As a preferred embodiment of the present application, the only change on the basis of Example 1 is that the mass ratio of sodium raxofelodinate to bismuth nitrate is 1:1.05, the yield is 89%, and the particle size distribution is 375-480nm (≥95%).

[0034] Example 4 As a preferred embodiment of the present application, the only change on the basis of Example 1 is that the mass ratio of sodium raxofelodinate to bismuth nitrate is 1:1.2, the yield is 78%, and the particle size distribution is 479-596nm (≥95%).

[0035] Comparative Example 1 As a comparative example of the present application, the only change on the basis of Example 1 is that the same ratio and solution concentration, temperature conditions are used in a batch stirring reactor, and continuous stirring is performed for 2h, followed by filtration, washing, and drying. The sample is marked as OPS. It is particularly pointed out that the comparative sample is a sample under the best process conditions, and the performance of the remaining samples under the process conditions of the batch stirring reactor is lower than that of the comparative sample.

[0036] Comparative Example 2 As a preferred embodiment of the present application, only the aging time is changed to 1 h based on Example 1, and the yield is 43%, and the particle size distribution is 157-428 nm (≥95%).

[0037] Test Example 1 Characterization means The infrared spectrum was measured by a Japan Shimadzu FT-IR 8900 infrared spectrometer (KBr pressed tablet); the sample morphology was observed by a Japan Hitachi S-450 scanning electron microscope; the particle size was analyzed by a U.S. BROOKHAVEN particle size analyzer; the thermal gravimetric analysis was performed by a U.S. TA TGA2950 thermal analysis system; the X-ray diffractometer was a Japan Rigaku Dmax-2000 type. The DSC analysis was performed by a Mettler Toledo DSC822 differential scanning calorimetry, and the operating conditions were as follows: flow rate 20 ml / min, N2protection, heating rate 10 ℃ / min, and heating range 20 ℃-250 ℃. The carbon and hydrogen contents in the sample were measured by a German Elementar UNICUBE model element analyzer (EA). The bismuth content was measured by an Agilent 5110 ICP-OES inductively coupled plasma emission spectrometer (ICP).

[0038] Example 1 was tested by using the above method.

[0039] As shown in Figure 1 , respectively, are the infrared spectra of resoxstat acid and bismuth resoxstat, it can be seen that except for the skeleton vibration peak (1500 cm -1 nearby) of the benzene ring, the in-plane bending vibration absorption peak (1093.56 cm -1 ) and the out-of-plane bending vibration absorption peak (694.33 cm -1 ) are basically unchanged, and the positions of most peaks are red shifted. 3378 cm -1 is the hydroxyl infrared absorption peak of resoxstat acid and bismuth resoxstat, 1634 cm -1 is the C=O anti-symmetric stretching vibration peak of -COOH, and compared with the infrared spectrum of resoxstat acid, a group of weak bands in 2500 cm-1-3000 cm-1 disappears in the infrared spectrum of bismuth resoxstat, which is a significant feature of the conversion of -COOH to bismuth carboxylate.

[0040] As shown in Figure 2As shown, it can be seen that the sample is uniformly spherical, the morphology is similar, the particle distribution is uniform, and the average particle size is about 500 nm. This is because the ultrasonic mixing reactor has good micro-mixing performance, and the synergistic effect of macro-mixing and micro-mixing is beneficial to the particle size distribution of bismuth resorcylate in the reaction precipitation process. The particle size and distribution of bismuth resorcylate are important parameters affecting its performance, and the combustion catalyst with small particle size and uniform distribution can provide more stable catalytic combustion efficiency As shown in Figure 3 , the particles below 375 nm account for 5%, and the particles below 480 nm account for 100%, that is, the particles between 375 and 480 nm account for 95%, and the most probable particle size is 420 nm, which is consistent with the particle size range measured by SEM, indicating that the particle size distribution of bismuth resorcylate is narrow.

[0041] As shown in Figure 4 , the sample was heated from 20°C to 800°C at a rate of 5°C / min in an air atmosphere, and it can be seen that there are three weight loss steps at 30°C~100°C, 100°C~150°C and 150°C~300°C. The weight loss of the first two steps is about 3% due to free water and bound water. The third step shows a clear vertical weight loss section, with a weight loss of about 35.4%, which can be attributed to the decomposition of the benzene ring of bismuth resorcylate. The residue at 800°C is yellow Bi2O3 powder, with a residual mass of 9.6 mg. Combined with the elemental analysis results (%), the C content is 22.22%, the H content is 1.33%, and the Bi content is 55.28%.

[0042] As shown in Figure 5 , the sample shows bismuth resorcylate characteristic peaks at 24.8°, 29.9°, 19.7°, 35.2° and 47.6.2°. There is no bismuth oxide impurity in the bismuth resorcylate sample, and the diffraction peak intensity is weak, with a widening phenomenon, indicating that the product has small particle size and poor crystallization degree, resulting in diffraction dispersion. By comparing the bismuth oxide standard card, the thermal decomposition residue shows bismuth oxide characteristic peaks belonging to monoclinic system at diffraction angles of 25.7°, 26.9°, 33.75° and 46°, indicating that new bismuth oxide is generated.

[0043] Test Example 2 Catalyst performance characterization Thermal decomposition catalytic experiment: reagents: nitrocellulose NC (11.9% N), nitroglycerin (NG), bismuth resorcylate (BiRes), and the reagent ratio is (NC+NG):BiRes=5:1(mol / mol). Nitrocellulose, nitroglycerin and bismuth resorcylate were weighed according to the proportion, then the nitrocellulose, nitroglycerin and bismuth resorcylate were placed in a stirring mixing kettle, fully stirred and then left still, centrifuged to remove water, and dried.

[0044] The decomposition heat of the pure component is approximately 2225 J / g, with a decomposition peak temperature of 204℃. The decomposition heat of NC+NG+OPS is approximately 2513 J / g, with a decomposition peak temperature of 201℃. The decomposition heat of NC+NG+NPS is approximately 2978 J / g, with a decomposition peak temperature of 199℃. Adding narrow-distribution NPS bismuth sappoocitrate lowers the decomposition peak temperature by 2℃ compared to adding ordinary OPS bismuth sappoocitrate, while increasing the decomposition heat by 18.5%. This indicates that narrow-distribution bismuth sappoocitrate can accelerate the decomposition rate of the absorbent, shorten the decomposition time, and promote a more complete decomposition reaction, significantly increasing the decomposition heat and thus improving the combustion efficiency of the double-base propellant.

[0045] Test Example 3 Catalytic combustion performance experiment: Basic formulation: 43% nitrocellulose and nitroglycerin; 45% RDX; 5% aluminum powder; 7% other additives; 3% combustion catalyst. Samples were prepared by absorption, water displacement, calendering, and stretching. The burning rate was determined using the target line method. A Φ5mm×150mm strip was impregnated with polyvinyl alcohol solution six times and dried at 20℃ and pressures of 2–22 MPa, with burning rate measured every 2 MPa. The pressure index was calculated using the empirical formula for burning rate: r = bPn, taking the logarithm of both sides: lgr = lgb + nlgP. The pressure index was calculated using burning rate data at two pressures; for example, if the two burning rates are r1 and r2, the corresponding pressures are P1 and P2.

[0046]

[0047] like Figure 7 The bismuth sappoocitrate samples with the addition of both standard-sized OPS and narrow-distribution NPS in the basic formulations shown exhibited accelerated combustion in the initial stage, producing a plateau catalytic combustion effect. The narrow-distribution NPS sample, in particular, showed a greater increase in combustion rate and a better catalytic effect. The combustion rate increased by more than 3 times at 4–6 MPa, more than 2 times at 8–12 MPa, and more than 1.5 times at 14–20 MPa. The combustion rate pressure index decreased from 0.96 to 0.38 within the 4–20 MPa pressure range, indicating that the narrow-distribution bismuth sappoocitrate sample had a more significant catalytic effect.

[0048] The above are the embodiments listed in this example. However, this example is not limited to the optional embodiments described above. Those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments. Anyone can derive other various forms of embodiments based on the inspiration of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example. The scope of protection of this example should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. A method for preparing a bismuth rasoxooctanoate combustion catalyst, characterized in that: First, resorcinol is dissolved in an alkaline sodium compound solution to form a sodium resorcinate solution. Then, the sodium resorcinate solution and bismuth nitrate solution are heated separately and fed into an ultrasonic mixing reactor to generate bismuth resorcinate precipitate. The bismuth resorcinate precipitate is then aged, filtered, washed and vacuum dried to obtain the combustion catalyst.

2. The method for preparing a bismuth rasoxooctanoate combustion catalyst according to claim 1, characterized in that: The alkaline sodium-containing compound solution is a sodium bicarbonate solution or a sodium hydroxide solution.

3. The method for preparing a bismuth rasoxooctanoate combustion catalyst according to claim 1, characterized in that: The mass ratio of sodium hydroxide solution to resorcinol is 1.0:1.0~1.5, and the final pH value of the reaction is controlled to be 7~8.

4. The method for preparing a bismuth rasoxooctanoate combustion catalyst according to claim 1, characterized in that: The mass ratio of sodium suximide solution to bismuth nitrate solution is 1.0:1.0~1.

8.

5. The method for preparing a bismuth rasoxooctanoate combustion catalyst according to claim 1, characterized in that: The sodium sucralose solution and bismuth nitrate solution are heated to 50-75°C.

6. The method for preparing a bismuth rasoxooctanoate combustion catalyst according to claim 1, characterized in that: The aging process involves aging at 70℃ for 2 to 5 hours.

7. The method for preparing a bismuth rasoxooctanoate combustion catalyst according to claim 1, characterized in that: The vacuum drying temperature is 80~95℃.

8. A bismuth rupex combustion catalyst, characterized in that: It was prepared using the method for preparing a bismuth retinoate combustion catalyst according to any one of claims 1-7.

9. The bismuth retinoic acid combustion catalyst according to claim 8, characterized in that: The combustion catalyst has the molecular formula BiC7H5O5.

10. A bismuth retinoic acid combustion catalyst according to claim 8, characterized in that: The combustion catalyst comprises 90% to 95% particles with a particle size of 375–480 nm. And / or the combustion catalyst contains 100% particles smaller than 480 nm; And / or the combustion catalyst contains 3% to 5% particles smaller than 375 nm.

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