Preparation method of large-particle-size ammonium perchlorate hollow microspheres

Abstract

The invention discloses a preparation method of large-particle-size ammonium perchlorate hollow microspheres, which is characterized in that pyridine is used as a solvent, butyl octadecenoate is used as an anti-solvent, and the ammonium perchlorate hollow microspheres are obtained by using an anti-solvent crystallization method. The particle size of the obtained large-particle-size ammonium perchlorate hollow microspheres is 100-200 microns, the sphericity degree is high, and the dispersity is good. The method disclosed by the invention is simple in preparation process, simple and convenient to operate and very suitable for large-scale production.

Description

Technical Field

[0001] The invention relates to a preparation method, in particular to a preparation method of large-diameter ammonium perchlorate hollow microspheres. Background Art

[0002] As a novel functional material, hollow materials have low density, high surface activity, and strong surface permeability compared to bulk materials, and show great potential application value in the fields of energetic materials, catalytic materials, photothermal materials, etc. In addition, due to their special structure, the hollow part of hollow materials can be used as a microreactor for the synthesis of other materials, and can also wrap other substances to form core-shell structure materials.

[0003] Ammonium perchlorate is a strong oxidant widely used in propellants, pyrotechnics, thermites and other fields. The morphology and particle size of ammonium perchlorate have a great influence on its sensitivity, charge density, and thermal decomposition performance. Hollow structure ammonium perchlorate has also attracted much attention in recent years due to its many advantages such as light weight, large specific surface area, and strong designability. Li Lan (Construction and Thermal Decomposition Performance of AP Hierarchical Structure Hollow Microspheres, Journal of Explosives and Propellants, 2021, 44, 769-775) used ice template method combined with freeze-drying technology to prepare hierarchical structure ammonium perchlorate hollow microspheres with a particle size of 0.5 to 2 microns. CN117285011A dissolves ammonium perchlorate in N,N-dimethylformamide (or dimethyl sulfoxide, N-methylpyrrolidone), then adds it to a high-viscosity oleic acid anti-solvent to crystallize and prepare hollow spherical ammonium perchlorate with a particle size of 10 to 50 microns. CN102718187A dissolves ammonium perchlorate in a N,N-dimethylformamide / acetone mixed solvent to prepare a saturated solution, and then adds it to the anti-solvent ethyl acetate to crystallize to obtain hollow cubic ammonium perchlorate with a particle size of 1 to 100 microns. It can be seen that the preparation of hollow structure ammonium perchlorate currently requires cumbersome freeze-drying process, or high viscosity anti-solvent, or mixed solvent with complex ratio to obtain hollow structure ammonium perchlorate, and the particle size of the hollow structure ammonium perchlorate does not exceed 100 microns. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing large-diameter ammonium perchlorate hollow microspheres. The method does not rely on a complicated freeze-drying process, does not require a mixed solvent or a high-viscosity anti-solvent, and adopts an improved anti-solvent crystallization method to prepare the ammonium perchlorate hollow microsphere product. The obtained ammonium perchlorate hollow microspheres have a particle size of 100 to 200 microns, high sphericity, good dispersibility, and are more suitable for industrial production.

[0005] The technical solution of the present invention is: a method for preparing large-diameter ammonium perchlorate hollow microspheres, using pyridine as a solvent and low-viscosity butyl octadecenoate as an anti-solvent, and using an anti-solvent crystallization method to obtain large-diameter ammonium perchlorate hollow microspheres with a particle size of 100 to 200 microns; the specific steps are as follows: (1) At a certain temperature, ammonium perchlorate is dissolved in a pyridine solvent to form a saturated ammonium perchlorate solution; (2) under stirring conditions, adding the saturated ammonium perchlorate solution of step 1 to the butyl octadecenoate anti-solvent at room temperature at a certain feeding rate, so that the ammonium perchlorate crystallizes due to supersaturation; (3) After the crystallization is complete, the product is separated, washed, and dried to obtain ammonium perchlorate hollow microspheres.

[0006] In step (1), the certain temperature is 5 to 30°C.

[0007] In step (2), the stirring condition is 400-600 rpm.

[0008] In step (2), the certain feeding rate is 2 to 20 mL / min.

[0009] In step (2), the volume ratio of the saturated ammonium perchlorate solution to butyl octadecenoate is controlled at 0.005 to 0.2.

[0010] In step (3), washing is performed with ethyl acetate and drying is performed at 50 to 80°C.

[0011] The beneficial effects of the present invention are: 1. The obtained ammonium perchlorate hollow microspheres have a particle size of 100 to 200 microns, large particle size, high sphericity and good dispersibility.

[0012] 2. The raw materials used are simple, only pyridine and butyl octadecenoate are needed. A reagent with low production cost.

[0013] 3. The butyl octadecenoate anti-solvent used has low viscosity, the product is easy to wash and has high purity.

[0014] 4. The preparation process is simple, the operation is easy, and it is suitable for large-scale production.

[0015] 5. The raw material ammonium perchlorate is industrial ammonium perchlorate, which has no restrictions on particle size, morphology or crystal form. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a scanning electron microscope image of the large-diameter ammonium perchlorate hollow microspheres obtained in Example 1; Figure 2 This is a scanning electron microscope image of the large-diameter ammonium perchlorate hollow microspheres obtained in Example 2; Figure 3 This is a scanning electron microscope image of the large-diameter ammonium perchlorate hollow microspheres obtained in Example 3; Figure 4 This is a scanning electron microscope image of the ammonium perchlorate obtained in Comparative Example 1; Figure 5 This is a scanning electron microscope image of the ammonium perchlorate obtained in Comparative Example 2; Figure 6 This is a scanning electron microscope image of the ammonium perchlorate obtained in Comparative Example 3; Figure 7 This is a scanning electron microscope image of the ammonium perchlorate obtained in Comparative Example 4. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further illustrated below in conjunction with embodiments and comparative examples, but they should not be construed as limitations on the technical solution, and all adaptive improvements based on these examples fall within the protection scope of the present invention.

[0018] Example 1: Preparation of large-diameter ammonium perchlorate hollow microspheres according to the following steps (1) dissolving ammonium perchlorate in pyridine solvent at 5°C to form a saturated ammonium perchlorate solution; (2) under stirring at 600 rpm, the saturated ammonium perchlorate solution of step 1 is added to the room temperature butyl octadecenoate anti-solvent at a feeding rate of 2 mL / min, and the ammonium perchlorate crystallizes due to supersaturation; wherein the volume ratio of the saturated ammonium perchlorate solution to butyl octadecenoate is controlled at 0.005; (3) After the crystallization is complete, the product is separated, washed with ethyl acetate, and dried at 50°C to obtain large-size ammonium perchlorate hollow microspheres. The scanning electron microscopy results are as follows: Figure 1 shown.

[0019] Example 2: Preparation of large-diameter ammonium perchlorate hollow microspheres according to the following steps (1) dissolving ammonium perchlorate in pyridine solvent at a temperature of 17.5°C to form a saturated ammonium perchlorate solution; (2) under stirring at 500 rpm, the saturated ammonium perchlorate solution of step 1 was added to the room temperature butyl octadecenoate anti-solvent at a feeding rate of 11 mL / min, and the ammonium perchlorate was crystallized due to supersaturation; wherein the volume ratio of the saturated ammonium perchlorate solution to butyl octadecenoate was controlled at 0.1025; (3) After the crystallization is complete, the product is separated, washed with ethyl acetate, and dried at 65°C to obtain large-size ammonium perchlorate hollow microspheres. The scanning electron microscopy results are as follows: Figure 2 shown.

[0020] Example 3: Preparation of large-diameter ammonium perchlorate hollow microspheres according to the following steps (1) dissolving ammonium perchlorate in pyridine solvent at 30°C to form a saturated ammonium perchlorate solution; (2) under stirring at 400 rpm, the saturated ammonium perchlorate solution of step 1 is added to the room temperature butyl octadecenoate anti-solvent at a feeding rate of 20 mL / min, and the ammonium perchlorate crystallizes due to supersaturation; wherein the volume ratio of the saturated ammonium perchlorate solution to butyl octadecenoate is controlled at 0.2; (3) After the crystallization is complete, the product is separated, washed with ethyl acetate, and dried at 80°C to obtain large-size ammonium perchlorate hollow microspheres. The scanning electron microscopy results are as follows: Figure 3 shown.

[0021] Comparative Example 1: (1) dissolving ammonium perchlorate in pyridine solvent at 5°C to form a saturated ammonium perchlorate solution; (2) under stirring at 600 rpm, adding the saturated ammonium perchlorate solution of step 1 to oleic acid at room temperature at a feeding rate of 2 mL / min to crystallize; wherein the volume ratio of the saturated ammonium perchlorate solution to oleic acid is controlled at 0.005; (3) After the crystallization is complete, the product is separated, washed with ethyl acetate, and dried at 50°C to obtain ammonium perchlorate aggregates with irregular morphology. The SEM image is as follows: Figure 5 shown.

[0022] Comparative Example 2: (1) dissolving ammonium perchlorate in pyridine solvent at a temperature of 15°C to form a saturated ammonium perchlorate solution; (2) adding the saturated ammonium perchlorate solution of step 1 to ethyl acetate at room temperature at a rate of 10 mL / min under stirring at 500 rpm to crystallize; wherein the volume ratio of the saturated ammonium perchlorate solution to ethyl acetate is controlled at 0.085; (3) After the crystallization is complete, the product is separated, washed with ethyl acetate, and dried at 60°C to obtain a mixture of ammonium perchlorate cubes and cuboids. The electron microscope scanning is as follows: Figure 6 shown.

[0023] Comparative Example 3: (1) At a temperature of 20°C, ammonium perchlorate is dissolved in a pyridine solvent to form a saturated ammonium perchlorate solution; (2) adding the saturated ammonium perchlorate solution of step 1 to butyl laurate at room temperature at a rate of 15 mL / min under stirring at 400 rpm to crystallize; wherein the volume ratio of the saturated ammonium perchlorate solution to butyl laurate is controlled at 0.155; (3) After the crystallization is complete, the product is separated, washed with ethyl acetate, and dried at 70°C to obtain ammonium perchlorate aggregates with irregular morphology. The SEM image is as follows: Figure 6 shown.

[0024] Comparative Example 4: (1) dissolving ammonium perchlorate in pyridine solvent at 30°C to form a saturated ammonium perchlorate solution; (2) adding the saturated ammonium perchlorate solution of step 1 to dimethyl carbonate at room temperature at a rate of 20 mL / min under stirring at 500 rpm to crystallize; wherein the volume ratio of the saturated ammonium perchlorate solution to dimethyl carbonate is controlled at 0.2; (3) After the crystallization is complete, the product is separated, washed with ethyl acetate, and dried at 80°C to obtain ammonium perchlorate cuboids. The scanning electron microscopy results are as follows: Figure 7 shown.

[0025] Figure 1-Figure 3 The scanning electron microscope images of the large-diameter ammonium perchlorate hollow microspheres obtained in Examples 1-3 are respectively; Figure 4-Figure 7 They are scanning electron microscope images of the ammonium perchlorate products obtained in Comparative Examples 1-4 respectively; it can be seen from the figure that when pyridine solvent is used for ammonium perchlorate, high-viscosity oleic acid is used as an anti-solvent to obtain ammonium perchlorate hollow microspheres; in addition, ethyl acetate, butyl laurate, dimethyl carbonate and other ester solvents are used instead of butyl octadecenoate to produce ammonium perchlorate hollow microspheres. It can be seen that the combination of pyridine solvent and butyl octadecenoate anti-solvent in the present invention is crucial to the formation of large-diameter ammonium perchlorate hollow microspheres.

Claims

1. A method for preparing large-diameter ammonium perchlorate hollow microspheres, characterized in that: Using pyridine as solvent and low-viscosity butyl octadecenoate as anti-solvent, large-diameter ammonium perchlorate hollow microspheres with a particle size of 100 to 200 microns are obtained by anti-solvent crystallization method. The specific steps are as follows: (1) At a certain temperature, ammonium perchlorate is dissolved in pyridine solvent to form a saturated ammonium perchlorate solution; (2) under stirring conditions, adding the saturated ammonium perchlorate solution of step 1 to the butyl octadecenoate anti-solvent at room temperature at a certain feeding rate, so that the ammonium perchlorate crystallizes due to supersaturation; (3) After the crystallization is complete, the product is separated, washed, and dried to obtain ammonium perchlorate hollow microspheres.

2. The method for preparing large-diameter ammonium perchlorate hollow microspheres according to claim 1, characterized in that: In step (1), the certain temperature is 5 to 30°C.

3. The method for preparing large-diameter ammonium perchlorate hollow microspheres according to claim 1, characterized in that: In step (2), the stirring condition is 400-600 rpm.

4. The method for preparing large-diameter ammonium perchlorate hollow microspheres according to claim 1, characterized in that: In step (2), the certain feeding rate is 2 to 20 mL / min.

5. The method for preparing large-diameter ammonium perchlorate hollow microspheres according to claim 1, characterized in that: In step (2), the volume ratio of the saturated ammonium perchlorate solution to butyl octadecenoate is controlled at 0.005 to 0.

2.

6. The method for preparing large-diameter ammonium perchlorate hollow microspheres according to claim 1, characterized in that: In step (3), washing is performed with ethyl acetate and drying is performed at 50 to 80°C.

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