Preparation method of hollow ammonium perchlorate micron cuboid

Abstract

The invention discloses a preparation method of a hollow ammonium perchlorate micron cuboid, which comprises the following specific steps: firstly, dissolving ammonium perchlorate in an ethylene glycol solvent to form an ammonium perchlorate saturated solution, and stirring the ammonium perchlorate saturated solution in a shaking table; then, adding an acetic acid anti-solvent into the saturated solution, and recrystallizing ammonium perchlorate due to the influence of supersaturation; and finally, when the crystallization process is completely finished, standing and separating the product, and washing and drying to obtain the hollow ammonium perchlorate micron cuboid. The hollow ammonium perchlorate micron cuboid obtained by the invention has good dispersity and narrower particle size distribution. The method disclosed by the invention is simple, safe, convenient to operate, low in cost and easy to realize large-scale production.

Description

Technical Field

[0001] The present invention relates to a preparation method, and specifically relates to a preparation method of hollow ammonium perchlorate microcuboids. Background Art

[0002] In the field of solid propellants, ammonium perchlorate is one of the most commonly used oxidants, and its weight ratio in solid propellants can be as high as 60% to 80%. Therefore, the performance of solid propellants will change with the change of the characteristics of ammonium perchlorate. In particular, the morphology and particle size of AP have a significant impact on its performance.

[0003] Hollow-structured ammonium perchlorate has attracted much attention in recent years due to its many advantages such as light weight, large specific surface area, and strong designability. Researchers have used various strategies to prepare hollow-structured ammonium perchlorate. CN117285011A dissolves ammonium perchlorate in N,N-dimethylformamide (or dimethyl sulfoxide, N-methylpyrrolidone), and then adds it to a high-viscosity oleic acid antisolvent to crystallize hollow spherical ammonium perchlorate. 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 the ice template method combined with freeze-drying technology. CN102718187A dissolves ammonium perchlorate in a mixed solvent of N,N-dimethylformamide / acetone, and then adds the ammonium perchlorate saturated solution to the antisolvent ethyl acetate, and strictly controls the process to crystallize hollow ammonium perchlorate cubes or cuboids.

[0004] It can be seen that the existing technology for obtaining hollow-structured ammonium perchlorate usually relies on complex freeze-drying processes, the use of high-viscosity antisolvents, or the use of mixed solvent systems. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of hollow ammonium perchlorate microcuboids. The resulting ammonium perchlorate is in the form of microcuboids, has a regular hollow structure, good dispersibility, a narrow particle size distribution, and the preparation method is simple, safe, convenient to operate, low in cost, and easy to realize large-scale production.

[0006] The technical solution of the present invention is: a preparation method of hollow ammonium perchlorate microcuboids, characterized in that: an acetic acid antisolvent is added to a saturated ethylene glycol solution of ammonium perchlorate, and the ammonium perchlorate solution recrystallizes due to supersaturation to obtain hollow ammonium perchlorate microcuboids; specifically including the following steps: Step 1: Dissolve ammonium perchlorate in an ethylene glycol solvent. After obtaining a saturated ammonium perchlorate solution, place it on a shaker and stir. Step 2: Add an acetic acid antisolvent to this saturated solution, and ammonium perchlorate recrystallizes due to supersaturation. Step 3: After the crystallization is complete, the product is allowed to stand for separation, washed, and dried to obtain hollow ammonium perchlorate micron cuboids.

[0007] The temperature of the ethylene glycol solvent in step 1 is 5-50°C.

[0008] The shaking speed in step 1 is 100 to 300 rpm.

[0009] The acetic acid anti-solvent in step 2 is added in one go.

[0010] The volume ratio of the acetic acid anti-solvent to the saturated ammonium perchlorate solution in step 2 is controlled at 40-100.

[0011] In the step 3, the product is washed with acetic acid and dried at 100°C.

[0012] The beneficial effects of the present invention are: 1. The raw materials used are simple, only ethylene glycol solvent and acetic acid are needed for anti-dissolution Two chemical reagents.

[0013] 2. Compared with the traditional anti-solvent crystallization process, the present invention adds the anti-solvent to the ammonium perchlorate solution at one time without adjusting the feeding rate, thereby achieving a faster crystallization speed.

[0014] 3. The preparation process is simple, there are fewer factors affecting the product morphology, and it is easy to control.

[0015] 4. The obtained hollow ammonium perchlorate micron cuboid has a length of 50 to 100 microns, a width of 20 to 40 microns, good dispersibility and a narrow particle size distribution.

[0016] 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

[0017] Figure 1 This is a scanning electron microscope image of the hollow ammonium perchlorate micron cuboid obtained in Example 1; Figure 2 This is a scanning electron microscope image of the hollow ammonium perchlorate micron cuboid obtained in Example 2; Figure 3 This is a scanning electron microscope image of the hollow ammonium perchlorate micron cuboid obtained in Example 3. DETAILED DESCRIPTION

[0018] 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.

[0019] Example 1: Preparation of hollow ammonium perchlorate micron cuboids according to the following specific steps Step 1: Ammonium perchlorate is dissolved in ethylene glycol solvent at a temperature of 5 °C. After obtaining a saturated ammonium perchlorate solution, it is placed on a shaker with a rotation speed of 300 rpm for stirring. Step 2: An acetic acid antisolvent is added to the above saturated solution at one time, and ammonium perchlorate undergoes recrystallization due to supersaturation. Among them, the volume ratio of the acetic acid antisolvent to the saturated ammonium perchlorate solution is 40. Step 3: After complete crystallization, the product is allowed to stand for separation, washed with acetic acid multiple times, and dried at 100 °C to obtain hollow ammonium perchlorate microcuboids.

[0020] Example 2: Hollow ammonium perchlorate microcuboids are prepared according to the following specific steps Step 1: Ammonium perchlorate is dissolved in ethylene glycol solvent at a temperature of 25.5 °C. After obtaining a saturated ammonium perchlorate solution, it is placed on a shaker with a rotation speed of 200 rpm for stirring. Step 2: An acetic acid antisolvent is added to the above saturated solution at one time, and ammonium perchlorate undergoes recrystallization due to supersaturation. Among them, the volume ratio of the acetic acid antisolvent to the saturated ammonium perchlorate solution is 70. Step 3: After complete crystallization, the product is allowed to stand for separation, washed with acetic acid multiple times, and dried at 100 °C to obtain hollow ammonium perchlorate microcuboids.

[0021] Example 3: Hollow ammonium perchlorate microcuboids are prepared according to the following specific steps Step 1: Ammonium perchlorate is dissolved in ethylene glycol solvent at a temperature of 50 °C. After obtaining a saturated ammonium perchlorate solution, it is placed on a shaker with a rotation speed of 100 rpm for stirring. Step 2: An acetic acid antisolvent is added to the above saturated solution at one time, and ammonium perchlorate undergoes recrystallization due to supersaturation. Among them, the volume ratio of the acetic acid antisolvent to the saturated ammonium perchlorate solution is 100. Step 3: After complete crystallization, the product is allowed to stand for separation, washed with acetic acid multiple times, and dried at 100 °C to obtain hollow ammonium perchlorate microcuboids.

[0022] The scanning electron microscope pictures of the hollow ammonium perchlorate microcuboids obtained in Examples 1 to 3 are respectively as Figure 1 , Figure 2 , Figure 3 shown. It can be seen from the figures that the obtained hollow ammonium perchlorate microcuboids are 50 - 100 microns in length, 20 - 40 microns in width, have good dispersibility, and a narrow particle size distribution.

Claims

1. A method for preparing hollow ammonium perchlorate micron cuboids, characterized in that: The acetic acid anti-solvent is added to a saturated solution of ammonium perchlorate in ethylene glycol, and the ammonium perchlorate solution is recrystallized due to supersaturation to obtain hollow ammonium perchlorate micron cuboids; the process specifically comprises the following steps: Step 1, dissolving ammonium perchlorate in ethylene glycol solvent to obtain a saturated ammonium perchlorate solution, and placing the solution on a shaker for stirring; Step 2, adding acetic acid anti-solvent to the saturated solution, and the ammonium perchlorate is recrystallized due to supersaturation; Step 3: After the crystallization is complete, the product is allowed to stand for separation, washed, and dried to obtain hollow ammonium perchlorate micron cuboids.

2. The method for preparing a hollow ammonium perchlorate micron cuboid according to claim 1, characterized in that: The temperature of the ethylene glycol solvent in step 1 is 5-50°C.

3. The method for preparing a hollow ammonium perchlorate micron cuboid according to claim 1, characterized in that: The shaking speed in step 1 is 100 to 300 rpm.

4. A hollow ammonium perchlorate micron cuboid and a preparation method thereof according to claim 1, characterized in that: The acetic acid anti-solvent in step 2 is added in one go.

5. The method for preparing a hollow ammonium perchlorate cuboid according to claim 1, characterized in that: The volume ratio of the acetic acid anti-solvent to the saturated ammonium perchlorate solution in step 2 is controlled at 40-100.

6. The hollow ammonium perchlorate micron cuboid and the preparation method thereof according to claim 1, characterized in that: In the step 3, the product is washed with acetic acid and dried at 100°C.

Images