Preparation method of superfine porous ammonium perchlorate

Abstract

The application discloses a preparation method of superfine porous ammonium perchlorate and belongs to the technical field of materials. The preparation method is as follows: ammonium perchlorate raw materials are dissolved in a mixed solvent to prepare an ammonium perchlorate saturated solution; then, a surfactant is added into the ammonium perchlorate saturated solution and stirred uniformly; then, the ammonium perchlorate saturated solution is added into a non-solvent at a constant speed, the ammonium perchlorate particles are precipitated while stirring, and the stirring is continued after the addition is completed; after the reaction is completed, the reaction solution is filtered, washed and dried to obtain the superfine porous ammonium perchlorate. The superfine porous ammonium perchlorate is obtained by dissolving the ammonium perchlorate in a mixed solution of methanol and triethanolamine through a solvent-non-solvent method and then precipitating the ammonium perchlorate from a non-solvent octane, the method is safe and reliable, the operation steps are simple, the cost is low, the method is suitable for industrial production, the particle size is controllable, and the superfine porous ammonium perchlorate is easy to prepare.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of materials, and particularly relates to a preparation method of superfine porous ammonium perchlorate. BACKGROUND

[0002] Ammonium perchlorate (AP) is one of the most widely used oxidizers in solid propellants, and accounts for 60% to 80% of the solid propellants. The performance (particle size and morphology) of AP greatly affects the performance of the propellants. The decrease of the particle size of AP can reduce the decomposition temperature and increase the burning rate and thermal decomposition efficiency. Due to the increase of the surface area and morphological characteristics, the micron and nanometer scale superfine AP particles have a great influence on the burning rate of the composite solid propellants. At present, the fine AP is still the main method used by researchers to improve the performance of the solid propellants, and the preparation of the superfine AP is also paid more and more attention by people.

[0003] Since AP is a flammable and explosive material, the temperature rise and spark generation should be avoided, and the strong impact and friction should not occur in the fine process to ensure the production safety. At present, the reported fine AP methods mainly include airflow crushing, vibration ball milling, spray drying, freeze drying and low-temperature crystallization. However, compared with these methods, the physical fine AP has safety hazards, and the low-temperature crystallization method has a high cost and is not suitable for large-scale production. The low-temperature crystallization method can prepare AP with a wide particle size range, has simple operation, low cost, high yield, short recrystallization time, safety and convenience, and strong controllability of particle size, and is suitable for industrial production. However, the solubility of AP in a single solvent is low, and the large-scale preparation cannot be achieved. SUMMARY

[0004] The application provides a preparation method of superfine porous ammonium perchlorate, which comprises the following steps:

[0005] The ammonium perchlorate raw material is dissolved in a mixed solvent to prepare an ammonium perchlorate saturated solution; then a surfactant is added into the ammonium perchlorate saturated solution and stirred uniformly; then the ammonium perchlorate saturated solution is uniformly added into a non-solvent, and the stirring is continued during the feeding, and the ammonium perchlorate particles are precipitated, and after the feeding is completed, the stirring is continued for the reaction; after the reaction is completed, the reaction solution is filtered, washed and dried to obtain the superfine porous ammonium perchlorate.

[0006] In the preparation method, the mixed solvent is a mixed solvent of methanol and triethanolamine; and the volume ratio of the methanol to the triethanolamine is selected from 7:3 to 4:6, and preferably 4:6.

[0007] In the preparation method, the mass fraction of the ammonium perchlorate in the saturated solution is selected from 22.96% to 33.54%, and preferably 33.54%.

[0008] In the above preparation method, the surfactant is stearic acid.

[0009] In the above preparation method, the mass fraction of the surfactant in the ammonium perchlorate saturated solution is selected from 3 to 8%, preferably 7.21%.

[0010] In the above preparation method, the non-solvent is octane.

[0011] In the above preparation method, the volume ratio of the ammonium perchlorate saturated solution to the non-solvent is selected from 1:3 to 1:20, preferably 1:20.

[0012] In the above preparation method, the feeding rate of the ammonium perchlorate saturated solution is selected from 0.5 to 5 mL / min.

[0013] In the above preparation method, the stirring speed after adding the material is selected from 200 to 1200 rpm.

[0014] In the above preparation method, the drying conditions for the ammonium perchlorate solid sample are selected from: temperature 60-80℃, drying time 2-4h.

[0015] In the above preparation method, the time for continuing the stirring reaction is selected from 5 to 10 minutes.

[0016] This invention provides an ultrafine porous ammonium perchlorate prepared by the above method.

[0017] This invention provides the application of the above-mentioned ultrafine porous ammonium perchlorate in the preparation of solid propellants.

[0018] The beneficial effects of this invention are as follows:

[0019] This invention utilizes a solvent-non-solvent method to first dissolve acrylamide (AP) in a mixed solution of methanol and triethanolamine, and then precipitate it using the non-solvent octane, thereby obtaining ultrafine porous AP. This method is safe, reliable, simple to operate, low in cost, suitable for industrial production, and allows for controllable particle size, facilitating the preparation of AP with fine particle sizes. AP has low solubility in both methanol and triethanolamine as individual solvents. However, by combining methanol and triethanolamine, the triethanolamine binds to the AP surface while the hydrophobic portion binds to methanol, thus improving the solubility of AP in both methanol and triethanolamine. Stearic acid is mixed with a saturated AP solution, and the adsorption of surfactants on specific crystal faces is used to control the final crystal particle size and morphology. As a non-solvent, octane has poor chemical reactivity and does not readily undergo various chemical reactions, thus enabling AP precipitation. After filtration and drying, ultrafine porous AP is obtained. The refined AP exhibits better thermal decomposition properties, facilitating its application. Furthermore, the two solvent compounding methods proposed in this invention can greatly improve the solubility of AP in these solvents at room temperature, which is beneficial to increasing the yield of ultrafine AP and reducing costs. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 SEM images of the ultra-fine porous AP sample prepared in Example 1; where the left image is a 20 μm field of view and the right image is a 10 μm field of view;

[0021] Figure 2 Particle size distribution plot of the ultra-fine porous AP sample prepared in Example 1;

[0022] Figure 3 Infrared plot; where the upper curve is the ultra-fine porous AP prepared in Example 1 and the lower curve is the raw material AP;

[0023] Figure 4 XRD plot of the ultra-fine porous AP sample prepared in Example 1 compared to the raw material AP and an AP standard card;

[0024] Figure 5 TG plot of the ultra-fine porous AP sample prepared in Example 1 compared to the raw material AP; where the left curve is the ultra-fine porous AP and the right curve is the raw material AP;

[0025] Figure 6 DSC plot of the ultra-fine porous AP sample prepared in Example 1 compared to the raw material AP; where the upper curve is the ultra-fine porous AP and the lower curve is the raw material AP;

[0026] Figure 7 SEM images of the ultra-fine porous AP sample prepared in Example 2; where the left image is a 20 μm field of view and the right image is a 5 μm field of view;

[0027] Figure 8 SEM images of the ultra-fine porous AP sample prepared in Example 3; where the left image is a 20 μm field of view and the right image is a 10 μm field of view;

[0028] Figure 9 SEM images of the ultra-fine porous AP sample prepared in Example 4; where the left image is a 20 μm field of view and the right image is a 10 μm field of view;

[0029] Figure 10 SEM images of the ultra-fine porous AP sample prepared in Example 5; where the left image is a 50 μm field of view and the right image is a 20 μm field of view;

[0030] Figure 11 SEM images of the ultra-fine porous AP sample prepared in Example 6; where the left image is a 20 μm field of view and the right image is a 10 μm field of view;

[0031] Figure 12 SEM images of the ultra-fine porous AP sample prepared in Example 7; where the left image is a 50 μm field of view and the right image is a 20 μm field of view;

[0032] Figure 13 SEM images of the ultra-fine porous AP sample prepared in Example 8, wherein the left image is a 50 μm field of view and the right image is a 10 μm field of view;

[0033] Figure 14 Picture of the AP sample prepared in Example 9 adhering to the wall of the beaker after the end of the anti-solvent recrystallization;

[0034] Figure 15 Picture of the state of the product after the addition of stearic acid; wherein, A is the state of the product; B indicates that the product does not adhere to the wall of the beaker; and C is the product after filtration;

[0035] Figure 16 SEM images of the ultra-fine porous AP sample prepared in Example 10, wherein the left image is a 20 μm field of view and the right image is a 10 μm field of view;

[0036] Figure 17 SEM images of the ultra-fine porous AP sample prepared in Example 12, wherein the left image is a 10 μm field of view and the right image is a 5 μm field of view. DETAILED DESCRIPTION

[0037] Other materials used in the present application, unless otherwise specified, can be obtained through commercial channels. Other terms used in the present application, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art. The present application is described in further detail below in conjunction with specific examples and with reference to the data. The following examples are merely intended to illustrate the present application and in no way limit the scope of the present application.

[0038] Example 1

[0039] The ultra-fine porous AP was prepared according to the following steps:

[0040] 4 mL of methanol and 6 mL of triethanolamine were mixed to obtain an AP solvent; 3800 mg of AP was then added and shaken to dissolve and mix uniformly to achieve maximum solubility of the AP, thereby obtaining a saturated AP solution (the mass fraction of the AP in the saturated solution was 33.54%); 1 mL of stearic acid was then added and continuously stirred on a magnetic stirrer for 2 h to mix uniformly; 5 mL of the AP saturated solution was then added to a beaker containing 100 mL of octane (a non-solvent) at a rate of 5 mL / min using a syringe pump, and continuously stirred at a stirring speed of 800 rpm; after the addition was completed, the reaction was continued for 5 min; after the reaction was completed, the AP mixture was suction filtered and washed with octane three times, and dried at 80 °C for 2 h to obtain a dried solid sample, i.e., the ultra-fine porous AP.

[0041] The adding amount of the AP is according to the test result (maximum solubility) of the solubility of the AP in the complexing solvent. In actual application, the AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining unsolved AP can be removed from the saturated solution by filtration or the like.

[0042] The SEM image of the superfine porous AP sample is shown in Figure 1 The prepared AP has small particle size and uniform morphology, and the particle size distribution diagram is shown in Figure 2 The particle size is mainly concentrated in 2-3 μm.

[0043] The infrared curves of the superfine porous AP and the raw material AP are shown in Figure 3

[0044] As shown in Figure 3 , the superfine AP has absorption peaks near 3300 cm -1 , 1420 cm -1 , 1080 cm -1 , 9335 cm -1 , and 625 cm -1 . After analysis, the peak at 3300 cm -1 is the stretching vibration peak of N-H, the peak near 1420 cm -1 is the bending vibration peak of N-H, and the peaks near 1080 cm -1 , 9335 cm -1 , and 625 cm -1 are the stretching vibration peaks of ClO4 - . It is found through comparison that the infrared curves of the superfine AP and the raw material AP are basically the same, indicating that the molecular structure of the prepared superfine AP does not change obviously.

[0045] As shown in Figure 4 , through XRD test of the raw material AP and the superfine AP and comparison with the AP standard card, it is found that the diffraction peaks of the superfine AP and the raw material AP are basically consistent with the standard AP card (JCPDS card No. 43-0468), and there is no new impurity peak, indicating that the crystal structure of the superfine AP obtained by the recrystallization technology does not change, and the preparation process does not introduce impurities, and belongs to high-purity preparation.

[0046] As shown in Figure 5 , according to the TG result, the thermal decomposition temperature of the superfine AP starts at 263.1℃, which is 34.3℃ earlier than that of the raw material AP, and the thermal decomposition starting temperature is greatly advanced. The thermal decomposition is relatively complete at 391.1℃. The mass loss of the thermal decomposition of the superfine AP is 95.477%, and the decomposition temperature of the raw material AP is relatively late, but the mass loss of the thermal decomposition is 96.3685%.

[0047] As​Figure 6 As shown, according to the DSC results, the thermal decomposition processes of the two APs are basically similar. The crystal transformation stages of the raw AP and the superfine AP are at 243.0°C and 242.0°C respectively. The crystal transformation stage of the superfine AP is 1°C higher than that of the raw AP. After the crystal transformation stages at 243°C and 242°C, the low-temperature decomposition of the two AP samples starts at about 300°C. The low-temperature decomposition peak of the superfine AP is at about 310.3°C, and the low-temperature decomposition peak of the raw AP is not obvious and is at about 318.8°C.

[0048] Meanwhile, the superfine AP has an obvious low-temperature decomposition peak at about 310.3°C, which indicates that the thermal decomposition performance of the superfine AP is better than that of the raw AP, and the smaller the particle size of the AP is, the more conducive to the thermal decomposition of the AP.

[0049] After the low-temperature decomposition, the two groups of samples enter the high-temperature decomposition stage respectively, but the high-temperature decomposition peak temperature of the superfine AP is lower and is at about 379.6°C. The high-temperature decomposition peak of the raw AP is at about 415.4°C, and the superfine AP is 35.8°C earlier than the raw AP.

[0050] Through the above results, it is shown that the superfine porous AP prepared by the solvent-non-solvent method has better thermal decomposition performance than the raw AP.

[0051] Example 2

[0052] The superfine porous AP is prepared by the following steps:

[0053] 7mL of methanol and 3mL of triethanolamine are uniformly mixed to serve as the AP solvent; then 3800mg of AP is added and shaken to be dissolved and uniformly mixed to make the AP reach the maximum solubility, so as to obtain an AP saturated solution (the mass fraction of the AP in the saturated solution is 22.96%); then 1mL of stearic acid is added, and the mixture is continuously stirred on a magnetic stirrer for 2h; at room temperature, 5mL of the AP saturated solution is added into a beaker containing 100mL of octane (non-solvent) by an injection pump at an injection speed of 5mL / min, and is continuously stirred at a stirring speed of 800rpm; after the addition is completed, the reaction is continued for 5min; after the reaction is completed, the AP mixture is filtered and washed with octane for three times, and is dried at 80°C for 2h to obtain a dried solid sample, i.e. the superfine porous AP.

[0054] The above AP addition amount is based on the test results (maximum solubility) of the solubility of the AP in the compounded solvent. In actual application, the AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining unsolved AP can be removed from the saturated solution by filtration or the like.

[0055] The SEM image of the above superfine porous AP sample is as shown in Figure 7The prepared AP has a particle size distribution of 3-7 μm and uneven morphology.

[0056] Example 3

[0057] The steps for preparing the ultrafine porous AP are as follows:

[0058] 5 mL of methanol and 5 mL of triethanolamine are mixed uniformly as the AP solvent; 3800 mg of AP is then added and shaken to dissolve uniformly to make the AP reach the maximum solubility, obtaining an AP saturated solution (the mass fraction of AP in the saturated solution is 24.03%); 1 mL of stearic acid is then added, and the mixture is continuously stirred on a magnetic stirrer for 2 h; at room temperature, 5 mL of the AP saturated solution is added to a beaker containing 100 mL of octane (non-solvent) through a syringe pump at an injection rate of 5 mL / min, and is continuously stirred at a stirring speed of 800 rpm; after the addition is completed, the reaction is continued for 5 min; after the reaction is completed, the AP mixture is suction filtered, washed with octane three times, and dried at 80°C for 2 h to obtain a dried solid sample, i.e., the ultrafine porous AP.

[0059] The above-mentioned addition amount of AP is based on the test results (maximum solubility) of the solubility of AP in the compounded solvent. In actual application, AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining undissolved AP can be removed from the saturated solution by filtration or the like.

[0060] The SEM image of the above-mentioned ultrafine porous AP sample is shown in Figure 8 The particle size is mainly distributed in 4-8 μm, and the morphology is uneven, with some large particles.

[0061] Example 4

[0062] The steps for preparing the ultrafine porous AP are as follows:

[0063] 5 mL of methanol and 5 mL of triethanolamine are mixed uniformly as the AP solvent; 3800 mg of AP is then added and shaken to dissolve uniformly to make the AP reach the maximum solubility, obtaining an AP saturated solution (the mass fraction of AP in the saturated solution is 24.03%); 1 mL of stearic acid is then added, and the mixture is continuously stirred on a magnetic stirrer for 2 h; at room temperature, 5 mL of the AP saturated solution is added to a beaker containing 100 mL of octane (non-solvent) through a syringe pump at an injection rate of 5 mL / min, and is continuously stirred at a stirring speed of 800 rpm; after the addition is completed, the reaction is continued for 5 min; after the reaction is completed, the AP mixture is suction filtered, washed with octane three times, and dried at 80°C for 2 h to obtain a dried solid sample, i.e., the ultrafine porous AP.

[0064] The addition amount of the AP is based on the test result (maximum solubility) of the solubility of the AP in the compounded solvent. In actual application, the AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining undissolved AP can be removed from the saturated solution by filtration or the like.

[0065] The SEM image of the above-mentioned superfine porous AP sample is shown in Figure 9 The prepared AP has irregular shape, uneven particle morphology and strip shape.

[0066] Example 5

[0067] The superfine porous AP is prepared by the following steps:

[0068] 4 mL of methanol and 6 mL of triethanolamine are uniformly mixed as the AP solvent; then 3800 mg of AP is added and shaken to dissolve and mix uniformly to make the AP reach the maximum solubility, to obtain an AP saturated solution (the mass fraction of the AP in the saturated solution is 33.54%); then 1 mL of stearic acid is added, and the mixture is continuously stirred on a magnetic stirrer for 2 h; at room temperature, 5 mL of the AP saturated solution is added to a beaker containing 100 mL of dichloromethane (non-solvent) by an injection pump at an injection speed of 5 mL / min, and is continuously stirred at a stirring speed of 800 rpm; after the addition is completed, the reaction is continued for 5 min; after the reaction is completed, the AP mixture is suction filtered, washed with n-hexane three times, and dried at 80°C for 2 h to obtain a dried solid sample, i.e. the superfine porous AP.

[0069] The addition amount of the AP is based on the test result (maximum solubility) of the solubility of the AP in the compounded solvent. In actual application, the AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining undissolved AP can be removed from the saturated solution by filtration or the like.

[0070] The SEM image of the above-mentioned superfine porous AP sample is shown in Figure 10 The prepared AP has irregular shape, uneven particle morphology and strip shape.

[0071] Example 6

[0072] The superfine porous AP is prepared by the following steps:

[0073] 4 mL of methanol and 6 mL of triethanolamine were mixed uniformly as the solvent of AP; then 3800 mg of AP was added and mixed uniformly to reach the maximum solubility of AP, to obtain a saturated solution of AP (the mass fraction of AP in the saturated solution was 33.54%); then 1 mL of stearic acid was added and continuously stirred on a magnetic stirrer for 2 h; at room temperature, 5 mL of the saturated solution of AP was injected into a beaker containing 100 mL of ethyl acetate (non-solvent) at a speed of 5 mL / min by using a syringe pump, and continuously stirred at a stirring speed of 800 rpm; after the addition was completed, the reaction was continued for 5 min; after the reaction was completed, the AP mixture was filtered and washed with n-hexane three times, and dried at 80°C for 2 h to obtain a dried solid sample, i.e. the ultrafine porous AP.

[0074] The above-mentioned addition amount of AP is based on the test results (maximum solubility) of the solubility of AP in the compounded solvent. In actual application, AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining undissolved AP can be removed from the saturated solution by filtration or the like.

[0075] The SEM image of the above-mentioned ultrafine porous AP sample is shown in Figure 11 The prepared AP is in the form of a flaky and large particle size, which does not meet the application requirements.

[0076] Example 7

[0077] The ultrafine porous AP was prepared by the following steps:

[0078] 4 mL of methanol and 6 mL of triethanolamine were mixed uniformly as the solvent of AP; then 3800 mg of AP was added and mixed uniformly to reach the maximum solubility of AP, to obtain a saturated solution of AP (the mass fraction of AP in the saturated solution was 33.54%); then 1 mL of stearic acid was added and continuously stirred on a magnetic stirrer for 2 h; at room temperature, 5 mL of the saturated solution of AP was injected into a beaker containing 100 mL of ethyl acetate (non-solvent) at a speed of 5 mL / min by using a syringe pump, and continuously stirred at a stirring speed of 800 rpm; after the addition was completed, the reaction was continued for 5 min; after the reaction was completed, the AP mixture was filtered and washed with n-hexane three times, and dried at 80°C for 2 h to obtain a dried solid sample, i.e. the ultrafine porous AP.

[0079] The above-mentioned addition amount of AP is based on the test results (maximum solubility) of the solubility of AP in the compounded solvent. In actual application, AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining undissolved AP can be removed from the saturated solution by filtration or the like.

[0080] The SEM image of the above-mentioned ultrafine porous AP sample is shown inFigure 12 As shown in the SEM image, the prepared AP is in flaky shape, with extremely uneven morphology and large particle size, which does not meet the application requirements.

[0081] Example 8

[0082] The steps for preparing the ultra-fine porous AP are as follows:

[0083] 4 mL of methanol and 6 mL of triethanolamine were mixed uniformly as the AP solvent; then 3800 mg of AP was added and shaken to dissolve and mix uniformly, so that the AP reached the maximum solubility, to obtain an AP saturated solution (the mass fraction of AP in the saturated solution was 33.54%); then 1 mL of sodium dodecyl sulfate (SDS) was added, and the mixture was continuously stirred on a magnetic stirrer for 2 h; at room temperature, 5 mL of the AP saturated solution was added to a beaker containing 100 mL of octane (non-solvent) at an injection speed of 5 mL / min by using a syringe pump, and the mixture was continuously stirred at a stirring speed of 800 rpm; after the addition was completed, the reaction was continued for 5 min; after the reaction was completed, the AP mixture was suction filtered and washed with octane three times, and then dried at 80°C for 2 h to obtain a dried solid sample, i.e., the ultra-fine porous AP.

[0084] The above-mentioned addition amount of AP is based on the test results (maximum solubility) of the solubility of AP in the compounded solvent. In actual application, AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining undissolved AP can be removed from the saturated solution by filtration or the like.

[0085] The SEM image of the above-mentioned ultra-fine porous AP sample is shown in FIG. 2. Figure 13 As shown in the SEM image, the prepared AP is in flaky shape, with extremely uneven morphology and large particle size, which does not meet the application requirements.

[0086] Example 9 (without adding a surfactant)

[0087] The steps for preparing the ultra-fine porous AP are as follows:

[0088] 4 mL of methanol and 6 mL of triethanolamine were mixed uniformly as the AP solvent; then 3800 mg of AP was added and shaken to dissolve and mix uniformly, so that the AP reached the maximum solubility, to obtain an AP saturated solution (the mass fraction of AP in the saturated solution was 33.54%); at room temperature, 5 mL of the AP saturated solution was added to a beaker containing 100 mL of octane (non-solvent) at an injection speed of 5 mL / min by using a syringe pump, and the mixture was continuously stirred at a stirring speed of 800 rpm; after the addition was completed, the reaction was continued for 5 min; after the reaction was completed, the AP mixture was suction filtered and washed with octane three times, and then dried at 80°C for 2 h to obtain a dried solid sample, i.e., the ultra-fine porous AP.

[0089] The addition amount of the AP is based on the test result (maximum solubility) of the solubility of the AP in the complexing solvent. In actual application, the AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining undissolved AP can be removed from the saturated solution by filtration or the like.

[0090] The image of the above-mentioned ultra-fine porous AP sample is shown in Figure 14 The prepared AP sample adheres to the wall of the beaker and cannot be separated from the solution to obtain the product. The reason is that in the anti-solvent recrystallization process, the supersaturation is large, and the increase of the stirring speed accelerates the agglomeration of the precipitated sample, and finally the agglomerates adhere to the wall of the beaker.

[0091] After adding stearic acid to it, the experiment is re-conducted and the contrast is obvious, as shown in Figure 15 The obtained solution is uniform and no agglomerated product appears, and the particles are small, do not adhere to the wall of the beaker, and are easy to separate from the solution, and the product can be easily obtained by filtration.

[0092] Example 10 (the solvent is only methanol)

[0093] The ultra-fine porous AP is prepared, and the steps are as follows:

[0094] 10 mL of methanol is used as the solvent of the AP; then 3800 mg of AP is added, shaken and dissolved to mix uniformly, so that the AP reaches the maximum solubility, to obtain a saturated solution of the AP (10 mL of methanol can only dissolve 580 mg of AP, and the solubility is very low, and the mass fraction of the AP in the saturated solution is 6.84%); then 1 mL of stearic acid is added, and the mixture is continuously stirred on a magnetic stirrer for 2 h; at room temperature, 5 mL of the saturated solution of the AP is injected into a beaker containing 100 mL of octane (non-solvent) at a speed of 5 mL / min by using a syringe pump, and the stirring speed is 800 rpm; after the addition is completed, the reaction is continued for 5 min; after the reaction is completed, the AP mixture is filtered, washed with octane three times, and dried at 80°C for 2 h to obtain a dried solid sample, i.e., the ultra-fine porous AP.

[0095] The addition amount of the AP is based on the test result (maximum solubility) of the solubility of the AP in the complexing solvent. In actual application, the AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent, and the remaining undissolved AP can be removed from the saturated solution by filtration or the like.

[0096] The SEM image of the above-mentioned ultra-fine porous AP sample is shown in Figure 16 The prepared AP has extremely uneven morphology and large particle size, which does not meet the application requirements.

[0097] Example 11 (the solvent is only triethanolamine)

[0098] The preparation of ultra-fine porous AP is as follows:

[0099] 10 mL of triethanolamine is used as the solvent of AP. Then 100 mg of AP is added and dissolved by shaking. It is found that AP is slightly soluble in triethanolamine by long-time shaking and dissolution. The mass fraction of AP in the solution is less than 1%, which has no experimental value.

[0100] Example 12 (solvent is a mixture of ethanol and triethanolamine)

[0101] The preparation of ultra-fine porous AP is as follows:

[0102] 4 mL of ethanol and 6 mL of triethanolamine are mixed uniformly as the solvent of AP. Then 3800 mg of AP is added and mixed uniformly by shaking to achieve the maximum solubility of AP, obtaining a saturated solution of AP (the mass fraction of AP in the saturated solution is 33.55%). Then 1 mL of stearic acid is added and mixed uniformly by continuously stirring on a magnetic stirrer for 2 h. At room temperature, 5 mL of the saturated solution of AP is injected into a beaker containing 100 mL of octane (non-solvent) by a syringe pump at a speed of 5 mL / min, and continuously stirred at a stirring speed of 800 rpm. After the addition is completed, the reaction is continued for 5 min. After the reaction is completed, the AP mixture is filtered and washed with octane three times, and dried at 80°C for 2 h to obtain a dried solid sample, i.e. ultra-fine porous AP.

[0103] The above-mentioned addition amount of AP is based on the test results of the solubility of AP in the solvent (maximum solubility). In actual application, AP can also be added in excess to ensure that it reaches the maximum solubility in the solvent. The remaining undissolved AP can be removed from the saturated solution by filtration or other methods.

[0104] The SEM image of the above-mentioned ultra-fine porous AP sample is shown in Figure 17 The prepared AP has extremely uneven morphology and large particle size, which does not meet the application requirements, so the solvent composition is not suitable for this system.

[0105] In summary, in the present application, the presence of surfactant makes the precipitated sample particle size smaller, and the solution obtained after reaction is uniform, no agglomeration product appears, which is easy to separate from the solution and obtain the product. The adsorption of surfactant on specific crystal plane can realize the control of the final crystal particle size and morphology. As a kind of surfactant, stearic acid is an organic compound composed of hydrophilic group and non-polar group with hydrophobicity, which can significantly reduce the interfacial tension. As a crystallization control agent to assist recrystallization, it can greatly reduce the interfacial tension of the solution, increase the diffusion coefficient of the solute, reduce the generation rate of crystal nucleus and improve the growth rate of crystal, so as to obtain particles with uniform morphology and small particle size. As a non-solvent, octane has poor chemical reactivity and is not easy to undergo various chemical reactions, so it is more suitable for preparing ultra-fine porous AP than dichloromethane and ethyl acetate.

[0106] The above description is only a preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any skilled person in the art can modify or change the above disclosed technical content to equivalent embodiments. However, any simple modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application without departing from the technical scheme of the present application still falls within the protection scope of the present application.

Claims

1. A method for preparing ultrafine porous ammonium perchlorate, characterized in that, Includes the following steps: Ammonium perchlorate raw material was dissolved in a mixed solvent to prepare a saturated ammonium perchlorate solution. Then, a surfactant was added to the saturated ammonium perchlorate solution and stirred until homogeneous. The saturated ammonium perchlorate solution was then added to a non-solvent at a uniform rate while stirring, causing ammonium perchlorate particles to precipitate. After the addition was completed, stirring was continued. After the reaction was completed, the reaction solution was filtered, washed, and dried to obtain ultrafine porous ammonium perchlorate. The mixed solvent is a mixture of methanol and triethanolamine; wherein the volume ratio of methanol to triethanolamine is selected from 7:3 to 4:6; the surfactant is stearic acid; and the non-solvent is octane.

2. The preparation method according to claim 1, characterized in that, The volume ratio of methanol to triethanolamine is 4:

6.

3. The preparation method according to claim 1, characterized in that, The mass fraction of the surfactant in the ammonium perchlorate saturated solution is selected from 3 to 8%.

4. The preparation method according to claim 1, characterized in that, The volume ratio of the ammonium perchlorate saturated solution to the non-solvent is selected from 1:3 to 1:

20.

5. The preparation method according to claim 1, characterized in that, The drying conditions for the ammonium perchlorate solid sample are selected from: temperature 60~80℃, drying time 2~4 h; the time for continued stirring reaction is selected from 5~10 min.

6. The ultrafine porous ammonium perchlorate prepared by the method according to any one of claims 1 to 5.

7. The application of the ultrafine porous ammonium perchlorate as described in claim 6 in the preparation of solid propellants.

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