Preparation method of hollow micron spherical ammonium perchlorate material

Abstract

The invention discloses a preparation method of a hollow micron spherical ammonium perchlorate material, which is characterized in that dimethyl sulfoxide is used as a solvent, nonanoic acid is used as an anti-solvent, polyvinylpyrrolidone is used as a surfactant, hollow micron spherical ammonium perchlorate is obtained by an anti-solvent crystallization method, and the average particle size is about 50 microns. The method is simple in process, safe and fast, and the obtained hollow micron spherical ammonium perchlorate material is high in purity, good in sphericity degree, good in dispersity and suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to a preparation method, and more particularly to a method for preparing a hollow microspherical ammonium perchlorate material. Background Art

[0002] Ammonium perchlorate is a strong oxidizer and is widely used in fields such as propellants, pyrotechnics, and thermite. The morphology of ammonium perchlorate has a great influence on its sensitivity, charge density, and thermal decomposition performance. Due to its many advantages such as light weight, large specific surface area, and strong designability, the preparation research of hollow-structured ammonium perchlorate materials has attracted much attention in recent years.

[0003] Li Lan (Construction and Thermal Decomposition Properties of AP Hierarchical Structure Hollow Microspheres, Journal of Explosives & Propellants, 2021, 44, 769 - 775) prepared hollow spherical ammonium perchlorate by using an ice template method combined with freeze-drying technology. This process has high complexity, is affected by various factors, has a high dependence on equipment, and has a relatively long preparation cycle.

[0004] CN102718187A dissolved ammonium perchlorate in a mixed solvent of N,N-dimethylformamide / acetone to form a saturated solution, and then added it to the antisolvent ethyl acetate for crystallization to obtain hollow cubic ammonium perchlorate. This method relies on the mixed solvent of N,N-dimethylformamide and acetone, and the product morphology is extremely sensitive to the ratio of the mixed solvent, resulting in poor regularity and uniformity of the product morphology.

[0005] CN117285011A dissolved ammonium perchlorate in N,N-dimethylformamide (or dimethyl sulfoxide, N-methylpyrrolidone), and then added it to the oleic acid antisolvent for crystallization to prepare hollow spherical ammonium perchlorate. In this method, the oleic acid antisolvent has a very high viscosity, resulting in difficult product washing and introducing impurities to a certain extent.

[0006] The invention patent with the application number 202510154408.2 dissolved ammonium perchlorate in a high-temperature N,N-dimethylformamide solvent, and then added it to a low-temperature carbon tetrachloride antisolvent at a slow feeding rate for crystallization to obtain hollow spherical ammonium perchlorate. This method requires the use of a high-temperature ammonium perchlorate solvent and a highly toxic carbon tetrachloride antisolvent, which poses challenges to process safety, and has a slow feeding rate and a long crystallization cycle.

[0007] The invention patent with the application number 202510154411.4 used pyridine as a solvent and butyl octadecenoate as an antisolvent to obtain large-particle-size ammonium perchlorate hollow microspheres by using an antisolvent crystallization method. In this method, the pyridine solvent has neurotoxicity and strong irritation, posing a safety hazard to product production.

[0008] It can be seen that it is very necessary to develop a simple, safe and fast method for preparing hollow ammonium perchlorate materials with high purity and high homogeneity. Summary of the Invention

[0009] The object of the present invention is to provide a method for preparing hollow micron-sized spherical ammonium perchlorate materials, which has simple, safe and fast process, and the obtained hollow micron-sized spherical ammonium perchlorate materials have high purity, good sphericity and good dispersibility, and are more suitable for industrial production.

[0010] The technical solution of the present invention is: a method for preparing hollow micron-sized spherical ammonium perchlorate materials, which is characterized in that: using dimethyl sulfoxide as a solvent, nonanoic acid as an antisolvent, and polyvinylpyrrolidone as a surfactant, and obtaining hollow micron-sized spherical ammonium perchlorate materials by the antisolvent crystallization method; the specific steps are as follows: (1) At a certain temperature, dissolve ammonium perchlorate in dimethyl sulfoxide solvent to form a saturated ammonium perchlorate solution; (2) Dissolve polyvinylpyrrolidone in nonanoic acid antisolvent; (3) Under stirring conditions, add the saturated ammonium perchlorate solution in step 1 to the nonanoic acid solution in step 2 at a certain feeding rate, and ammonium perchlorate crystallizes due to supersaturation; (4) After complete crystallization, separate, wash and dry the product to obtain hollow micron-sized spherical ammonium perchlorate.

[0011] In step (1), the certain temperature is 20-35 °C.

[0012] In step (2), the concentration of polyvinylpyrrolidone in the nonanoic acid solution is 0.25-1 g / L.

[0013] In step (3), the stirring conditions are 400-600 rpm.

[0014] In step (3), the certain feeding rate is 10-30 mL / min.

[0015] In step (3), the temperature of the nonanoic acid solution is 15-30 °C.

[0016] In step (3), the volume ratio of the saturated ammonium perchlorate solution to nonanoic acid is controlled at 0.005-0.2.

[0017] In step (4), wash with ethyl acetate and dry at 50-80 °C.

[0018] The beneficial effects of the present invention are: 1. Using a single dimethyl sulfoxide solvent, there are few influencing factors for the product; and dimethyl sulfoxide has low cost and good safety.

[0019] 2. Nonanoic acid anti-solvent has low viscosity, is easy to wash, and the product has high purity.

[0020] 3. The feeding rate is fast and the product preparation cycle is short.

[0021] 4. The product has regular morphology and good hollow sphericity.

[0022] 5. The raw material ammonium perchlorate is industrial ammonium perchlorate, with no limitation on particle size, morphology, or crystal form. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the scanning electron microscope image of the hollow microspherical ammonium perchlorate obtained in Example 1; Figure 2 It is the scanning electron microscope image of the hollow microspherical ammonium perchlorate obtained in Example 2; Figure 3 It is the scanning electron microscope image of the hollow microspherical ammonium perchlorate obtained in Example 3; Figure 4 It is the scanning electron microscope image of the ammonium perchlorate obtained in Comparative Example 1; Figure 5 It is the scanning electron microscope image of the ammonium perchlorate obtained in Comparative Example 2; Figure 6 It is the scanning electron microscope image of the ammonium perchlorate obtained in Comparative Example 3; Figure 7 It is the scanning electron microscope image of the ammonium perchlorate obtained in Comparative Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0025] The technical solution of the present invention will be further described below in conjunction with examples and comparative examples, but it should not be construed as a limitation to the technical solution. Any adaptive improvements based on this belong to the protection scope of the present invention.

[0026] Example 1: The following steps are used to prepare hollow microspherical ammonium perchlorate (1) At a temperature of 20 °C, ammonium perchlorate is dissolved in dimethyl sulfoxide solvent to form an ammonium perchlorate saturated solution; (2) Polyvinylpyrrolidone is dissolved in nonanoic acid anti-solvent, and the concentration of polyvinylpyrrolidone in the nonanoic acid solution is 0.25 g / L; (3) Under the stirring condition of 600 rpm, the ammonium perchlorate saturated solution in step 1 is added to the nonanoic acid solution at a temperature of 15 °C at a feeding rate of 10 mL / min, and ammonium perchlorate crystallizes due to supersaturation; wherein, the volume ratio of the ammonium perchlorate saturated solution to nonanoic acid is controlled at 0.005; (4) After crystallization is complete, the product is separated, washed with ethyl acetate, and dried at 50 °C to obtain hollow microspherical ammonium perchlorate.

[0027] Comparative Example 1: The step parameters are the same as those in Example 1, except that N,N-dimethylformamide is used as the solvent.

[0028] Example 2: Hollow microspherical ammonium perchlorate was prepared by the following steps (1) At a temperature of 27.5 °C, ammonium perchlorate was dissolved in dimethyl sulfoxide solvent to form a saturated ammonium perchlorate solution; (2) Polyvinylpyrrolidone was dissolved in nonanoic acid antisolvent, and the concentration of polyvinylpyrrolidone in the nonanoic acid solution was 0.625 g / L; (3) Under stirring conditions of 500 rpm, the saturated ammonium perchlorate solution in step 1 was added to the nonanoic acid solution at a temperature of 20 °C at a feeding rate of 20 mL / min, and ammonium perchlorate crystallized due to supersaturation; among them, the volume ratio of the saturated ammonium perchlorate solution to nonanoic acid was controlled at 0.1025; (4) After crystallization was complete, the product was separated, washed with ethyl acetate, and dried at 65 °C to obtain hollow microspherical ammonium perchlorate.

[0029] Comparative Example 2: The step parameters are the same as those in Example 2, except that N-methylpyrrolidone is used as the solvent.

[0030] Example 3: Hollow microspherical ammonium perchlorate was prepared by the following steps (1) At a temperature of 35 °C, ammonium perchlorate was dissolved in dimethyl sulfoxide solvent to form a saturated ammonium perchlorate solution; (2) Polyvinylpyrrolidone was dissolved in nonanoic acid antisolvent, and the concentration of polyvinylpyrrolidone in the nonanoic acid solution was 1.0 g / L; (3) Under stirring conditions of 400 rpm, the saturated ammonium perchlorate solution in step 1 was added to the nonanoic acid solution at a temperature of 30 °C at a feeding rate of 30 mL / min, and ammonium perchlorate crystallized due to supersaturation; among them, the volume ratio of the saturated ammonium perchlorate solution to nonanoic acid was controlled at 0.2; (4) After crystallization was complete, the product was separated, washed with ethyl acetate, and dried at 80 °C to obtain hollow microspherical ammonium perchlorate.

[0031] Comparative Example 3: The step parameters are the same as those in Example 3, except that pyridine is used as the solvent.

[0032] Comparative Example 4: The step parameters are the same as those in Example 3, except that polyvinylpyrrolidone was not dissolved in the nonanoic acid antisolvent.

[0033] Figure 1 、 Figure 2 、 Figure 3 are the scanning electron microscope pictures of the hollow microspherical ammonium perchlorate obtained in Examples 1-3, respectively; Figures 4 - 7These are the scanning electron microscope images of the ammonium perchlorate products obtained in Comparative Examples 1-4. From these images, it can be seen that when dimethyl sulfoxide is used as the ammonium perchlorate solvent and recrystallization is carried out in a nonanoic acid solution dissolving polyvinylpyrrolidone, hollow microspherical ammonium perchlorate with high sphericity and good dispersibility can be obtained ( Figures 1 - 3 ). However, when N,N-dimethylformamide, N-methylpyrrolidone or pyridine is used to replace dimethyl sulfoxide in the present invention as the ammonium perchlorate solvent, even when using a nonanoic acid solution containing polyvinylpyrrolidone under the same conditions, it is still impossible to successfully prepare hollow microspherical ammonium perchlorate ( Figures 4 - 6 ). In addition, even when dimethyl sulfoxide is used as the ammonium perchlorate solvent, recrystallization in a nonanoic acid antisolvent without dissolving polyvinylpyrrolidone also cannot obtain hollow microspherical ammonium perchlorate ( Figure 7 ). Thus, it can be seen that the combination of using dimethyl sulfoxide as the solvent, nonanoic acid as the antisolvent and polyvinylpyrrolidone as the surfactant proposed in the present invention is crucial for the formation of hollow microspherical ammonium perchlorate.

Claims

1. A method for preparing a hollow micron spherical ammonium perchlorate material, characterized in that: Using dimethyl sulfoxide as solvent, nonanoic acid as anti-solvent, and polyvinyl pyrrolidone as surfactant, hollow micron spherical ammonium perchlorate material is obtained by anti-solvent crystallization method; the specific steps are as follows: (1) At a certain temperature, ammonium perchlorate is dissolved in dimethyl sulfoxide solvent to form a saturated ammonium perchlorate solution; (2) dissolving polyvinyl pyrrolidone in nonanoic acid antisolvent; (3) under stirring conditions, adding the saturated ammonium perchlorate solution of step 1 to the nonanoic acid solution of step 2 at a certain feeding rate, so that the ammonium perchlorate crystallizes due to supersaturation; (4) After the crystallization is complete, the product is separated, washed, and dried to obtain hollow micron-shaped ammonium perchlorate.

2. The method for preparing the hollow micron spherical ammonium perchlorate material according to claim 1, characterized in that: In step (1), the certain temperature is 20-35°C.

3. The method for preparing the hollow micron spherical ammonium perchlorate material according to claim 1, characterized in that: In step (2), the concentration of polyvinyl pyrrolidone in the nonanoic acid anti-solvent is 0.25 to 1 g / L.

4. The method for preparing the hollow micron spherical ammonium perchlorate material according to claim 1, characterized in that: In step (3), the stirring condition is 400-600 rpm.

5. The method for preparing the hollow micron spherical ammonium perchlorate material according to claim 1, characterized in that: In step (3), the certain feeding rate is 10 to 30 mL / min.

6. The method for preparing the hollow micron spherical ammonium perchlorate material according to claim 1, characterized in that: In step (3), the temperature of the nonanoic acid solution is 15 to 30 °C.

7. A hollow micron spherical ammonium perchlorate material and a preparation method thereof according to claim 1, characterized in that: In step (3), the volume ratio of the saturated ammonium perchlorate solution to nonanoic acid is controlled at 0.005 to 0.

2.

8. The method for preparing the hollow micron spherical ammonium perchlorate material according to claim 1, characterized in that: In step (4), washing is performed with ethyl acetate and drying is performed at 50 to 80°C.

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