Spherical ammonium dinitramide and normal-temperature ultrasonic preparation method thereof

Abstract

The invention discloses a normal-temperature ultrasonic preparation method of spherical ammonium dinitramide, which comprises the following steps: adding ammonium dinitramide particles and an auxiliary agent into an organic solvent, and stirring for 10-30 minutes in a temperature range of 20-35 DEG C to obtain an ammonium dinitramide solution; putting the ammonium dinitramide solution into an ultrasonic instrument, and carrying out ultrasonic treatment for 5-15 minutes at set ultrasonic power and ultrasonic frequency; the preparation method comprises the following steps: under a stirring condition, dropwise adding an ammonium dinitramide solution into dichloromethane at a certain dropwise adding temperature, and after dropwise adding, filtering and drying to obtain the ammonium dinitramide. Wherein the mass ratio of the ammonium dinitramide to the organic solvent to the auxiliary agent to the dichloromethane is 1: (10-22) mL: (0.01-0.02) g: (80-100) mL. According to the method, normal-temperature ultrasonic crystallization is used for replacing melting granulation, operation is convenient, cost is low, operation is carried out at normal pressure, and large-scale production can be achieved. The melting temperature of the ammonium dinitramide provided by the invention is increased compared with that of the raw material ADN, the particle size of the spherical ADN is between 10 microns and 500 microns, the melting temperature is 89.2-92.30 DEG C, the sphericity is greater than or equal to 0.8, the impact sensitivity is 15.2-20.0 J, and the friction sensitivity is 74-81%.

Description

Technical Field

[0001] The invention belongs to the technical field of energetic materials, and in particular relates to spherical ammonium dinitramide and a normal-temperature ultrasonic preparation method thereof. Background Art

[0002] Ammonium dinitramide (ADN) is an energetic material with excellent performance. It has become an important resource for developing new high-energy, insensitive, low-signal, and environmentally friendly explosive products, and has become one of the research hotspots in the field of solid propellants in recent years. However, ADN has a strong hygroscopicity, which has become a major reason affecting its widespread application. The crystalline ADN obtained by the commonly used recrystallization method has the disadvantages of many crystal defects, easy hygroscopicity, and high sensitivity. These disadvantages limit the application of ADN in propellants and gas generators. In order to overcome these disadvantages, ADN must be sphericalized.

[0003] At present, the research on ADN spheroidization has formed some relatively mature production processes, such as cooling medium dispersion method, molten droplet dispersion method, vacuum dispersion method and sedimentation tower spheroidization method. Among them, the ADN granulation process mentioned by Ulrich Teipel et al. is to add ADN and paraffin oil into a container with a stirring and heat exchange system, heat to melt ADN, form an oil-in-water emulsion with paraffin oil, and then cool to form spheres. Due to the low viscosity of the dispersion medium paraffin oil, the surface interaction between it and the ADN droplets is small. The molten ADN droplets are not easy to disperse in the paraffin oil, and the droplets after dispersion have poor spheroidization ability. In this way, after cooling and solidification, the spheroidization rate of ADN particles is not high. The particle size distribution range of spherical ADN is relatively wide (10μm to 600μm) and is difficult to control. HEINTZ added crude ADN to a stainless steel reactor, and when it melted, opened the pneumatic valve at the bottom of the reactor. Due to the action of gravity, liquid ADN enters the nozzle; then pressurized nitrogen is used to spray the ADN liquid through the nozzle. The ADN droplets are then cooled and solidified into spherical particles. Using different nozzles and nitrogen pressures, the particle size can be controlled. The disadvantage of this method is that it requires the use of specific reaction instruments, which is costly. When the above process is expanded to an industrial scale, a very large reactor and high energy are required for melting and cooling. The method proposed by Yang Rongjie et al. for preparing spherical ammonium dinitramide crystals with the assistance of ultrasound has the main disadvantages of a narrow particle size adjustment range of only 3 to 20 μm, making it difficult to obtain spherical ammonium dinitramide with larger particle sizes, and it is difficult to achieve regulation of the sphericity and sensitivity of ADN, which is in urgent need of improvement. Summary of the invention

[0004] In response to the above technical requirements, the present invention proposes a spherical ammonium dinitramide and a room temperature ultrasonic preparation method thereof to solve the problem of poor compatibility between macromolecular prepolymer and ADN particles in the existing coating anti-hygroscopic method, thereby achieving effective control of ADN particle size and sphericity, and reducing ADN friction sensitivity and impact sensitivity.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing spherical ammonium dinitramide by ultrasonic treatment at room temperature comprises the following steps:

[0007] Step 1, adding ammonium dinitramide particles and an auxiliary agent into an organic solvent, stirring for 10 min to 30 min at a temperature range of 20 to 35° C., to obtain an ammonium dinitramide solution;

[0008] Step 2, placing the ammonium dinitramide solution in an ultrasonic instrument, and ultrasonically treating it for 5 minutes to 15 minutes at a set ultrasonic power and ultrasonic frequency;

[0009] Step 3, under stirring conditions, adding the ammonium dinitramide solution dropwise into dichloromethane at a certain dropping temperature, filtering and drying after the dropping is completed;

[0010] Wherein, the mass ratio of the ammonium dinitramide, the organic solvent, the auxiliary agent and the dichloromethane is 1:(10-22):(0.01-0.02):(80-100).

[0011] The present invention also has the following technical features:

[0012] Furthermore, the organic solvent is selected from one or both of toluene and xylene.

[0013] Furthermore, the auxiliary agent is N-methyl-p-nitroaniline or diphenylamine.

[0014] Furthermore, the ultrasonic power is 100-500W, and the ultrasonic frequency is 20-50kHz.

[0015] Furthermore, the dropping temperature in step 3 is 20-40°C.

[0016] The invention also discloses spherical ammonium dinitramide prepared by the preparation method.

[0017] Furthermore, the particle size of the ammonium dinitramide is 10 μm to 500 μm, the melting temperature is 89.2 to 92.30° C., the sphericity is ≥ 0.8, the impact sensitivity is 15.2 J to 20.0 J, and the friction sensitivity is 54% to 67%.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) Compared with conventional methods, the method of the present invention uses room temperature ultrasonic crystallization granulation. Under the action of ultrasonic waves, the crystals are well dispersed to form spherical ammonium dinitramide crystals with uniform morphology and size. The method of the present invention achieves controllable classification of spherical particle size by adjusting the ratio of raw material components and reaction conditions such as reaction temperature, ultrasonic power, sound frequency and dropping temperature. The method of the present invention is easy to operate and has low cost.

[0020] (2) The particle size of the ammonium dinitramide provided by the present invention is between 10 μm and 500 μm, the melting temperature is 89.2 to 92.30° C., the sphericity is ≥ 0.8, the impact sensitivity is 15.2 J to 20.0 J, and the friction sensitivity is 54% to 67%, and the product performance is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a SEM picture of the ammonium dinitramide raw material used in the present invention.

[0022] Figure 2 It is a SEM picture of the spherical ammonium dinitramide prepared in Example 1 of the present invention.

[0023] Figure 3 It is the DSC chart of the ammonium dinitramide raw material used in the present invention.

[0024] Figure 4 It is the DSC chart of the spherical ammonium dinitramide prepared in Example 1 of the present invention.

[0025] Figure 5 It is the SEM picture of the spherical ammonium dinitramide prepared in Comparative Example 1.

[0026] Figure 6 It is the SEM picture of the spherical ammonium dinitramide prepared in Comparative Example 2.

[0027] Figure 7 This is the SEM image of the spherical ammonium dinitramide prepared in Comparative Example 3.

[0028] Figure 8 It is the SEM picture of the spherical ammonium dinitramide prepared in Comparative Example 4.

[0029] Fig. 9 This is a SEM image of the spherical ammonium dinitramide prepared in Comparative Example 5.

[0030] Fig.10 This is a SEM image of the spherical ammonium dinitramide prepared in Comparative Example 6.

[0031] The specific contents of the present invention are further explained in detail below in conjunction with the accompanying drawings and specific implementation methods. DETAILED DESCRIPTION

[0032] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0033] Unless otherwise specified, the raw materials used in the following examples, such as dichloromethane, toluene, and N-methyl-p-nitroaniline, are all commercially available. Ammonium dinitramide was prepared by the Xi'an Modern Chemistry Research Institute with a purity of 98.0%, an impact sensitivity of 9.3 J, and a friction sensitivity of 54%.

[0034] In the following embodiments:

[0035] The particle size test was carried out using the dry screening method in GJB772A-1997 403.1 explosives test method.

[0036] The sphericity test is carried out by laser particle size analyzer.

[0037] The impact sensitivity test is carried out using the impact sensitivity test method in GJB770A-97.

[0038] Friction sensitivity test is carried out according to the friction sensitivity test method in GJB770A-97.

[0039] Example 1

[0040] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 5 g of ammonium dinitramide (ADN) to 100 g of toluene, and adding 0.1 g of N-methyl-p-nitroaniline, stirring at 25° C. for 30 min, and ultrasonically treating for 10 min under the conditions of an ultrasonic power of 300 W and an ultrasonic frequency of 40 kHz; adding 500 g of dichloromethane to a four-necked bottle, and dropwise adding the ultrasonically treated ammonium dinitramide solution to the dichloromethane under stirring at 30° C., filtering the solution after the dropwise addition to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 4.5 g of spherical ADN solid.

[0041] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 300 μm to 450 μm, the average particle size is 373 μm, the melting temperature is 92.30° C., the sphericity is ≥ 0.91, the impact sensitivity is 18.8 J, and the friction sensitivity is 60%.

[0042] Structural analysis

[0043] 1. Scanning electron microscopy (SEM) analysis

[0044] In this embodiment, the raw material of ammonium dinitramide and the prepared spherical ammonium dinitramide were subjected to scanning electron microscope (SEM) analysis, and the results are as follows: Figure 1and Figure 2 shown.

[0045] As can be seen from the figure: the ammonium dinitramide raw material is in the form of flakes or sticks, has serious accumulation and adhesion, and has large and uneven particles. In contrast, the ammonium dinitramide crystal sample obtained in this embodiment is spherical, has controllable particle size, uniform particle size, and good flowability.

[0046] 2. Differential Scanning Calorimetry (DSC)

[0047] In this example, the raw material of ammonium dinitramide and the prepared spherical ammonium dinitramide were subjected to differential scanning calorimetry. The results are as follows: Figure 3 and Figure 4 shown.

[0048] It can be seen from the figure that the ammonium dinitramide raw material undergoes a melting process and a thermal decomposition process at 88.70°C and 200.27°C, respectively, while the ammonium dinitramide crystalline sample prepared in this embodiment has a melting temperature increased by 3.6°C while maintaining the thermal decomposition temperature, so it has better thermal stability.

[0049] Example 2

[0050] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 5 g of ammonium dinitramide (ADN) to 50 g of toluene, and adding 0.1 g of N-methyl-p-nitroaniline, stirring at 25° C. for 30 min, and ultrasonically treating for 10 min under the conditions of an ultrasonic power of 300 W and an ultrasonic frequency of 40 kHz; adding 500 g of dichloromethane to a four-necked bottle, and dropwise adding the ultrasonically treated ammonium dinitramide solution to the dichloromethane under stirring at 30° C., filtering the solution after the dropwise addition to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 4.5 g of spherical ADN solid.

[0051] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 200 μm to 280 μm, the average particle size is 233 μm, the melting temperature is 91.80° C., the sphericity is ≥ 0.87, the impact sensitivity is 17.5 J, and the friction sensitivity is 66%.

[0052] Example 3

[0053] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 1 g of ADN to 10 g of xylene, and adding 0.01 g of diphenylamine, stirring at 20° C. for 10 min, ultrasonically treating for 5 min under the conditions of an ultrasonic power of 250 W and an ultrasonic frequency of 30 kHz, adding 80 g of dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 20° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 0.8 g of spherical ADN solid.

[0054] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 100 μm to 190 μm, the average particle size is 150 μm, the melting temperature is 89.2° C., the sphericity is ≥ 0.93, the impact sensitivity is 16.4 J, and the friction sensitivity is 64%.

[0055] Example 4

[0056] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 1 g of ADN to 10 g of xylene, and adding 0.01 g of diphenylamine, stirring at 20° C. for 10 min, ultrasonically treating for 5 min under the conditions of an ultrasonic power of 250 W and an ultrasonic frequency of 30 kHz, adding 220 g of dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 20° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 0.9 g of spherical ADN solid.

[0057] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 50 μm to 95 μm, the average particle size is 81 μm, the melting temperature is 90.4° C., the sphericity is ≥ 0.86, the impact sensitivity is 19.7 J, and the friction sensitivity is 58%.

[0058] Example 5

[0059] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 1 g of ADN to 10 g of xylene, and adding 0.01 g of diphenylamine, stirring at 20° C. for 10 min, ultrasonically treating for 5 min under the conditions of an ultrasonic power of 500 W and an ultrasonic frequency of 50 kHz, adding 220 g of dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 20° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 0.9 g of spherical ADN solid.

[0060] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 20 μm to 50 μm, the average particle size is 30 μm, the melting temperature is 91.0° C., the sphericity is ≥ 0.92, the impact sensitivity is 19.1 J, and the friction sensitivity is 65%.

[0061] Example 6

[0062] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 1 g of ADN to 10 g of xylene, and adding 0.01 g of diphenylamine, stirring at 30° C. for 20 min, ultrasonically treating for 5 min under the conditions of an ultrasonic power of 250 W and an ultrasonic frequency of 30 kHz, adding 80 g of dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 20° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 0.8 g of spherical ADN solid.

[0063] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 80 μm to 150 μm, the average particle size is 114 μm, the melting temperature is 89.7° C., the sphericity is ≥ 0.84, the impact sensitivity is 15.8 J, and the friction sensitivity is 69%.

[0064] Example 7

[0065] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 1.5 g ADN to 20 g xylene, and adding 0.02 g N-methyl-p-nitroaniline, stirring at 35° C. for 15 min, ultrasonically treating for 10 min under the conditions of an ultrasonic power of 400 W and an ultrasonic frequency of 40 kHz, adding 130 g dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 35° C., filtering the solution after the dripping is complete to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 1.2 g of spherical ADN solid.

[0066] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 200 μm to 280 μm, the average particle size is 246 μm, the melting temperature is 91.6° C., the sphericity is ≥ 0.89, the impact sensitivity is 19.4 J, and the friction sensitivity is 55%.

[0067] Example 8

[0068] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 1.5 g ADN to 20 g xylene, and adding 0.02 g N-methyl-p-nitroaniline, stirring at 35° C. for 15 min, ultrasonically treating for 15 min under the conditions of an ultrasonic power of 400 W and an ultrasonic frequency of 40 kHz, adding 130 g dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 35° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 1.2 g of spherical ADN solid.

[0069] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 160 μm to 220 μm, the average particle size is 195 μm, the melting temperature is 90.4° C., the sphericity is ≥ 0.94, the impact sensitivity is 15.9 J, and the friction sensitivity is 59%.

[0070] Example 9

[0071] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 2.0 g of ADN to 25 g of toluene, and adding 0.02 g of diphenylamine, stirring at 30° C. for 12 min, ultrasonically treating for 7 min under the conditions of an ultrasonic power of 200 W and an ultrasonic frequency of 20 kHz, adding 180 g of dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 28° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 1.8 g of spherical ADN solid.

[0072] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 400 μm to 460 μm, the average particle size is 429 μm, the melting temperature is 90.4° C., the sphericity is ≥ 0.89, the impact sensitivity is 18.4 J, and the friction sensitivity is 61%.

[0073] Example 10

[0074] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 2.5 g ADN to 40 g xylene, and adding 0.03 g N-methyl-p-nitroaniline, stirring at 31° C. for 18 min, ultrasonically treating for 9 min under the conditions of an ultrasonic power of 100 W and an ultrasonic frequency of 30 kHz, adding 230 g dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 32° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 2.2 g of spherical ADN solid.

[0075] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 200 μm to 290 μm, the average particle size is 245 μm, the melting temperature is 91.9° C., the sphericity is ≥ 0.90, the impact sensitivity is 17.7 J, and the friction sensitivity is 65%.

[0076] Embodiment 11

[0077] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 3.0 g of ADN to 52 g of toluene, and adding 0.05 g of diphenylamine, stirring at 29° C. for 24 min, ultrasonically treating for 13 min under the conditions of an ultrasonic power of 400 W and an ultrasonic frequency of 50 kHz, adding 290 g of dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 38° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 2.6 g of spherical ADN solid.

[0078] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 70 μm to 150 μm, the average particle size is 98 μm, the melting temperature is 89.8° C., the sphericity is ≥ 0.86, the impact sensitivity is 19.7 J, and the friction sensitivity is 60%.

[0079] Example 12

[0080] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 3.5 g ADN to 76 g xylene, and adding 0.06 g N-methyl-p-nitroaniline, stirring at 34° C. for 28 min, ultrasonically treating for 15 min under the conditions of an ultrasonic power of 500 W and an ultrasonic frequency of 50 kHz, adding 330 g dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 26° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 3.2 g of spherical ADN solid.

[0081] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 210 μm to 300 μm, the average particle size is 257 μm, the melting temperature is 90.7° C., the sphericity is ≥ 0.90, the impact sensitivity is 16.9 J, and the friction sensitivity is 58%.

[0082] Example 13

[0083] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 3.5 g ADN to 76 g xylene, and adding 0.06 g N-methyl-p-nitroaniline, stirring at 34° C. for 28 min, ultrasonically treating for 15 min under the conditions of an ultrasonic power of 500 W and an ultrasonic frequency of 50 kHz, adding 330 g dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 40° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 3.2 g of spherical ADN solid.

[0084] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 140 μm to 190 μm, the average particle size is 164 μm, the melting temperature is 91.8° C., the sphericity is ≥ 0.84, the impact sensitivity is 18.2 J, and the friction sensitivity is 61%.

[0085] Embodiment 14

[0086] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 4.0 g of ADN to 84 g of toluene, and adding 0.07 g of diphenylamine, stirring at 29° C. for 18 min, ultrasonically treating for 9 min under the conditions of an ultrasonic power of 200 W and an ultrasonic frequency of 30 kHz, adding 380 g of dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 38° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 3.6 g of spherical ADN solid.

[0087] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 410 μm to 480 μm, the average particle size is 444 μm, the melting temperature is 92.1° C., the sphericity is ≥ 0.83, the impact sensitivity is 19.1 J, and the friction sensitivity is 67%.

[0088] Embodiment 15

[0089] In accordance with the above technical scheme, the present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 4.5 g ADN to 92 g xylene, and adding 0.08 g diphenylamine, stirring at 34° C. for 28 min, ultrasonically treating for 12 min under the conditions of an ultrasonic power of 400 W and an ultrasonic frequency of 40 kHz, adding 440 g dichloromethane to a four-necked bottle, and dripping the ammonium dinitramide solution into the dichloromethane under stirring at 29° C., filtering the solution after the dripping is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 4.3 g of spherical ADN solid.

[0090] According to the test, the particle size of the spherical ADN solid prepared in this embodiment ranges from 260 μm to 330 μm, the average particle size is 292 μm, the melting temperature is 90.4° C., the sphericity is ≥ 0.89, the impact sensitivity is 18.1 J, and the friction sensitivity is 57%.

[0091] It can be seen from Examples 1 to 15 that:

[0092] The method of the present invention uses normal temperature ultrasonic crystallization granulation. Under the action of ultrasonic waves, the crystals can be well dispersed to form spherical ADN crystals with uniform morphology and size. By adjusting the raw material component ratio, and adjusting the reaction conditions such as reaction temperature, ultrasonic power, ultrasonic frequency and dropping temperature, the controllable classification of spherical particle size can be achieved. The method of the present invention is easy to operate and has low cost. The particle size of the prepared ammonium dinitramide is controlled between 10μm and 500μm, the particle size range is larger, the applicability is wider, the melting temperature is 89.2-92.30°C, the sphericity is ≥0.8, the impact sensitivity is 15.2J-20.0J, the friction sensitivity is 74%-81%, and the product performance is significantly improved.

[0093] Comparative Example 1

[0094] The present comparative example discloses a method for preparing spherical ammonium dinitramide. The raw material components and proportions used in the present comparative example are the same as those in Example 1, except that ultrasonic treatment is not used in the preparation process of the present comparative example. Specifically, the method comprises: adding 5 g of ammonium dinitramide (ADN) to 100 g of toluene, and adding 0.1 g of N-methyl-p-nitroaniline, stirring at 25° C. for 30 min, adding 500 g of dichloromethane to a four-necked bottle, and dropwise adding the ultrasonically treated ammonium dinitramide solution to the dichloromethane under stirring at 30° C., filtering the solution after the dropwise addition is completed to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 4.4 g of spherical ADN solid.

[0095] After testing, the particle size of the spherical ADN solid prepared in this comparative example ranges from 550 μm to 650 μm, the average particle size is 597 μm, the melting temperature is 90.07° C., the sphericity is ≥0.50, the impact sensitivity is 9.4 J, and the friction sensitivity is 73%.

[0096] The comparative example obtains spherical ammonium dinitramide with large particle size, and the sphericity, impact sensitivity and friction sensitivity of the spherical ammonium dinitramide obtained in the comparative example are inferior to those of the spherical ammonium dinitramide obtained by the method of the present invention.

[0097] Comparative Example 2

[0098] This comparative example discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature. The raw material components and proportions used in this comparative example are the same as those in Example 1, except that the ultrasonic treatment conditions used in step 2 of this comparative example are different. In this comparative example, the ultrasonic treatment is performed for 10 minutes under the conditions of an ultrasonic power of 1000 W and an ultrasonic frequency of 60 kHz; and finally 4.6 g of spherical ADN solid is obtained.

[0099] After testing, the particle size of the spherical ADN solid prepared in this comparative example ranges from 300 μm to 450 μm, the average particle size is 376 μm, the melting temperature is 89.71° C., the sphericity is ≥0.64, the impact sensitivity is 9.6 J, and the friction sensitivity is 72%.

[0100] The sphericity, impact sensitivity and friction sensitivity of the spherical ammonium dinitramide prepared in this comparative example are not as good as those of the spherical ammonium dinitramide prepared by the method of the present invention.

[0101] Comparative Example 3

[0102] This comparative example discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature. The preparation method adopted in this comparative example is the same as that in Example 1, except that the organic solvent used in this comparative example is benzene. 4.0 g of spherical ADN solid is finally obtained in this comparative example.

[0103] After testing, the particle size of the spherical ADN solid prepared in this comparative example ranges from 480 μm to 650 μm, the average particle size is 557 μm, the melting temperature is 93.40° C., the sphericity is ≥0.66, the impact sensitivity is 10.7 J, and the friction sensitivity is 80%.

[0104] The sphericity, impact sensitivity and friction sensitivity of the spherical ammonium dinitramide prepared in this comparative example are not as good as those of the spherical ammonium dinitramide prepared by the method of the present invention.

[0105] Comparative Example 4

[0106] This comparative example discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature. The main raw material components and preparation method used in this comparative example are the same as those in Example 1, with the only difference being that the auxiliary agent selected in this comparative example is sodium p-toluenesulfonate. 4.9 g of spherical ADN solid is obtained in this comparative example.

[0107] After testing, the particle size of the spherical ADN solid prepared in this comparative example ranges from 270 μm to 400 μm, the average particle size is 349 μm, the melting temperature is 88.44° C., the sphericity is ≥0.71, the impact sensitivity is 10.7 J, and the friction sensitivity is 77%.

[0108] The sphericity, impact sensitivity and friction sensitivity of the spherical ammonium dinitramide prepared in this comparative example are not as good as those of the spherical ammonium dinitramide prepared by the method of the present invention.

[0109] Comparative Example 5

[0110] This example discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature. The main raw material components and preparation method used in this comparative example are the same as those in Example 1, with the only difference being that dichloromethane is replaced by acetone in this comparative example, and finally 4.4 g of spherical ADN solid is obtained.

[0111] After testing, the particle size of the spherical ADN solid prepared in this comparative example ranges from 250 μm to 550 μm, the average particle size is 360 μm, the melting temperature is 91.66° C., the sphericity is ≥0.48, the impact sensitivity is 10.4 J, and the friction sensitivity is 70%.

[0112] The sphericity, impact sensitivity and friction sensitivity of the spherical ammonium dinitramide prepared in this comparative example are not as good as those of the spherical ammonium dinitramide prepared by the method of the present invention.

[0113] Comparative Example 6

[0114] The present embodiment discloses a method for preparing spherical ammonium dinitramide by ultrasound at room temperature, comprising: adding 5 g of ammonium dinitramide (ADN) to 100 g of toluene, and adding 0.1 g of N-methyl-p-nitroaniline, stirring at 25° C. for 30 min, and ultrasonically treating for 10 min under the conditions of an ultrasonic power of 300 W and an ultrasonic frequency of 40 kHz; adding 500 g of dichloromethane to a constant pressure dropping funnel, and dropping the dichloromethane into the ammonium dinitramide solution that has been ultrasonically treated under stirring at 30° C., filtering the solution after the dropping is complete to obtain a filter cake; placing the filter cake in a dryer, and drying to constant weight to obtain 4.6 g of spherical ADN solid.

[0115] After testing, the particle size of the spherical ADN solid prepared in this comparative example ranges from 400 μm to 550 μm, the average particle size is 476 μm, the melting temperature is 91.47° C., the sphericity is ≥0.77, the impact sensitivity is 9.8 J, and the friction sensitivity is 72%.

[0116] The sphericity, impact sensitivity and friction sensitivity of the spherical ammonium dinitramide obtained in this comparative example are worse than those in Example 1.

[0117] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0118] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

Claims

1. A method for preparing spherical ammonium dinitramide by ultrasound at room temperature, characterized in that: The following steps are involved: Step 1, adding ammonium dinitramide particles and an auxiliary agent into an organic solvent, stirring for 10 min to 30 min at a temperature range of 20 to 35° C., to obtain an ammonium dinitramide solution; Step 2, placing the ammonium dinitramide solution in an ultrasonic instrument, and ultrasonically treating it for 5 minutes to 15 minutes at a set ultrasonic power and ultrasonic frequency; Step 3, under stirring conditions, dropwise add the ultrasonically treated ammonium dinitramide solution into dichloromethane at a certain dropping temperature, and after the dropping is completed, filter and dry to obtain; Wherein, the mass ratio of the ammonium dinitramide, the organic solvent, the auxiliary agent and the dichloromethane is 1:(10-22):(0.01-0.02):(80-100).

2. The method for preparing spherical ammonium dinitramide by ultrasound at room temperature as claimed in claim 1, characterized in that: The organic solvent is selected from one or both of toluene and xylene.

3. The method for preparing spherical ammonium dinitramide by ultrasound at room temperature as claimed in claim 1, characterized in that: The auxiliary agent is N-methyl-p-nitroaniline or diphenylamine.

4. The method for preparing spherical ammonium dinitramide by ultrasound at room temperature as claimed in claim 1, characterized in that: The ultrasonic power is 10-800W, and the ultrasonic frequency is 20-50Hz.

5. The method for preparing spherical ammonium dinitramide by ultrasound at room temperature as claimed in claim 1, characterized in that: The dropping temperature in step 3 is 20-40°C.

6. Spherical ammonium dinitramide obtained by the preparation method according to any one of claims 1 to 5.

7. The spherical ammonium dinitramide according to claim 6, characterized in that: The ammonium dinitramide has a particle size of 10 μm to 500 μm, a melting temperature of 89.2 to 92.30° C., a sphericity of ≥0.8, an impact sensitivity of 15.2 J to 20.0 J, and a friction sensitivity of 74% to 81%.

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