Spherical ammonium dinitramide and its normal-temperature ultrasonic preparation method

Abstract

The application discloses a normal-temperature ultrasonic preparation method of spherical ammonium dinitramide, which comprises the following steps: adding ammonium dinitramide particles and an additive into an organic solvent, stirring for 10-30 minutes at a temperature of 20-35 DEG C to obtain an ammonium dinitramide solution; placing the ammonium dinitramide solution into an ultrasonic instrument, and ultrasonically treating for 5-15 minutes at a set ultrasonic power and frequency; and adding the ammonium dinitramide solution into dichloromethane at a certain dropping temperature under stirring, and obtaining the spherical ammonium dinitramide after filtration and drying; wherein the mass ratio of the ammonium dinitramide, the organic solvent, the additive and the dichloromethane is 1:10-22 mL:0.01-0.02 g:80-100 mL. The method of the application uses normal-temperature ultrasonic crystallization instead of melting granulation, and has the advantages of convenient operation, low cost, normal-pressure operation and large-scale production. The melting temperature of the ammonium dinitramide provided by the application is higher than that of raw material ADN, the particle size of the spherical ADN is between 10 mu m and 500 mu m, 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 J-20.0 J, and the friction sensitivity is 74%-81%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energetic materials, and particularly relates to a spherical ammonium dinitramide and a normal-temperature ultrasonic preparation method thereof. BACKGROUND

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

[0003] At present, some mature production processes have been formed for the spheroidization of ADN, such as the cooling medium dispersion method, the molten droplet dispersion method, the vacuum dispersion method and the settling tower balling method. Among them, the ADN granulation process mentioned by Ulrich Teipel et al. is to add ADN and paraffin oil into a container with stirring and heat exchange system, heat to melt ADN, form water-in-oil emulsion with paraffin oil, and then cool to form a ball. Since the viscosity of the dispersion medium paraffin oil is small, the surface interaction between paraffin oil and ADN droplets is small, the molten ADN droplets are not easy to disperse in paraffin oil, and the dispersed droplets have poor balling ability, so the spheroidization rate of ADN particles is not high after cooling and solidification. The particle size distribution range of spherical ADN is relatively wide (10-600 μm) and difficult to control. HEINTZ adds coarse ADN into a stainless steel reactor, opens the bottom pneumatic valve of the reactor when it is melted, and ADN liquid enters the nozzle under the action of gravity; then ADN liquid is sprayed out through the nozzle by using pressurized nitrogen. ADN droplets are then cooled and solidified into spherical particles. By using different nozzles and nitrogen pressures, the particle size can be controlled. The defects of this method are that special reaction instruments are needed, and the cost is high. When the above process is expanded to an industrial scale, a very large reactor and high energy are needed for melting and cooling. The method for preparing spherical ammonium dinitramide crystals with the aid of ultrasonic proposed by Yang Rongjie et al. mainly has the defects that the particle size adjustment range is narrow, only 3-20 μm, it is difficult to prepare spherical ammonium dinitramide with larger particle size, and it is difficult to control the spheroidization and sensitivity of ADN, which needs to be improved. SUMMARY

[0004] To address the above technical requirements, this invention proposes a spherical ammonium dinitramide and its room-temperature ultrasonic preparation method, in order to solve the problem of poor compatibility between macromolecular prepolymers and ADN particles in existing coating and moisture-proofing methods, thereby achieving effective control of ADN particle size and sphericity, as well as reducing the friction sensitivity and impact sensitivity of ADN.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for preparing spherical ammonium dinitramide at room temperature via ultrasonication includes the following steps:

[0007] Step 1: Add the ammonium dinitramide granules and additives to an organic solvent and stir for 10 to 30 minutes at a temperature range of 20 to 35°C to obtain an ammonium dinitramide solution;

[0008] Step 2: Place the ammonium dinitrate solution in an ultrasonic instrument and sonicate it for 5 to 15 minutes at the set ultrasonic power and frequency.

[0009] Step 3: Under stirring conditions, add the dinitramide ammonium solution dropwise to dichloromethane at a certain dropping temperature. After the addition is complete, filter and dry to obtain the final product.

[0010] The mass ratio of the dinitramide ammonium, organic solvent, additives and 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 described in step 3 is 20–40°C.

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

[0017] Furthermore, 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 ≥ 0.8, an impact sensitivity of 15.2 J to 20.0 J, and a friction sensitivity of 54% to 67%.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] (1) Compared with the conventional method, the method of the present application uses normal temperature ultrasonic crystallization granulation, under the action of ultrasonic waves, the crystal is well dispersed, forming spherical ammonium dinitramide crystals with uniform morphology and size; the method of the present application realizes controllable classification of spherical particle size by adjusting the ratio of raw material components, and by adjusting the reaction conditions such as reaction temperature, ultrasonic power, acoustic frequency and dropping temperature; the method of the present application is easy to operate and has low cost.

[0020] (2) The particle size of the ammonium dinitramide provided by the present application is between 10 μm and 500 μm, the melting temperature is 89.2-92.30 ℃, the sphericity is ≥0.8, the impact sensitivity is 15.2 J-20.0 J, the friction sensitivity is 54%-67%, and the performance of the product has been obviously improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the SEM graph of the ammonium dinitramide raw material used in the present application.

[0022] Figure 2 is the SEM graph of the spherical ammonium dinitramide prepared in Example 1 of the present application.

[0023] Figure 3 is the DSC graph of the ammonium dinitramide raw material used in the present application.

[0024] Figure 4 is the DSC graph of the spherical ammonium dinitramide prepared in Example 1 of the present application.

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

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

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

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

[0029] Figure 9 is the SEM graph of the spherical ammonium dinitramide prepared in Comparative Example 5.

[0030] Figure 10 is the SEM graph of the spherical ammonium dinitramide prepared in Comparative Example 6.

[0031] The specific content of the present application is further explained in detail in combination with the drawings and specific embodiments. DETAILED DESCRIPTION

[0032] The following gives specific embodiments of the present application, it is to be noted that the present application is not limited to the following specific embodiments, any equivalent transformation made on the basis of the technical scheme of the present application falls within the protection scope of the present application.

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

[0034] In the following examples:

[0035] The particle size test adopts the particle size dry screening method in the explosive test method of GJB772A-1997.

[0036] The sphericity test is tested by a laser particle size analyzer.

[0037] The impact sensitivity test is tested by the impact sensitivity test method in GJB770A-97.

[0038] The friction sensitivity test is tested by the friction sensitivity test method in GJB770A-97

[0039] Example 1

[0040] According to the above technical scheme, the present embodiment discloses a spherical ammonium dinitramide normal temperature ultrasonic preparation method, comprising: adding 5g of ammonium dinitramide (ADN) into 100g of toluene, and adding 0.1g of N-methyl p-nitroaniline, stirring at 25℃ for 30min, and ultrasonic treatment for 10min under the condition of ultrasonic power of 300W and ultrasonic frequency of 40kHz; adding 500g of dichloromethane in a four-necked flask, and adding the ultrasonic treated ammonium dinitramide solution into the dichloromethane under the stirring condition at 30℃, filtering the solution after the addition is completed, and obtaining a filter cake; placing the filter cake into a dryer, drying to a constant weight, and obtaining 4.5g of spherical ADN solid.

[0041] After detection, the particle size range of the spherical ADN solid prepared in the present embodiment is 300μm-450μm, the average particle size is 373μm, the melting temperature is 92.30℃, the sphericity is ≥0.91, the impact sensitivity is 18.8J, and the friction sensitivity is 60%.

[0042] Structural analysis

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

[0044] In the present embodiment, scanning electron microscope (SEM) analysis is performed on the ammonium dinitramide raw material and the prepared spherical ammonium dinitramide, and the results are as follows: Figure 1and Figure 2 as shown.

[0045] As can be seen from the figure, the ammonium dinitramide raw material is in the form of sheet or rod, with serious adhesion and large and uneven particle size. In contrast, the ammonium dinitramide crystal sample prepared in the embodiment is in the form of sphere, with controllable particle size, uniform particle size and good flowability.

[0046] 2. Differential scanning calorimetry (DSC)

[0047] In the embodiment, differential scanning calorimetry detection was performed on the ammonium dinitramide raw material and the prepared spherical ammonium dinitramide, and the results are shown in Figure 3 and Figure 4 as shown.

[0048] As can be seen from the figure, the ammonium dinitramide raw material respectively undergoes a melting process at 88.70°C and a thermal decomposition process at 200.27°C, while the ammonium dinitramide crystal sample prepared in the embodiment has a melting temperature increased by 3.6°C under the condition of maintaining the thermal decomposition temperature, thus having better thermal stability.

[0049] Example 2

[0050] According to the above technical solution, the embodiment discloses a method for preparing spherical ammonium dinitramide at room temperature by ultrasonic treatment, which comprises the following steps: adding 5 g of ammonium dinitramide (ADN) into 50 g of toluene, and adding 0.1 g of N-methyl-p-nitroaniline, stirring at 25°C for 30 min, and then performing ultrasonic treatment under the condition of ultrasonic power of 300 W and ultrasonic frequency of 40 kHz for 10 min; adding 500 g of dichloromethane into a four-necked flask, and then adding the ultrasonically treated ammonium dinitramide solution into the dichloromethane under the stirring condition at 30°C, filtering the solution after the addition is completed, and obtaining a filter cake; and placing the filter cake into a dryer, and drying until the weight is constant, thereby obtaining 4.5 g of spherical ADN solid.

[0051] It is detected that the particle size of the spherical ADN solid prepared in the embodiment is in the range of 200 μm to 280 μm, the average particle size is 233 μm, the melting temperature is 91.80°C, the sphericity is greater than or equal to 0.87, the impact sensitivity is 17.5 J, and the friction sensitivity is 66%.

[0052] Example 3

[0053] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 1g of ADN is added into 10g of dimethylbenzene, 0.01g of diphenylamine is added, stirring is carried out at 20℃ for 10min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 250W and the ultrasonic frequency is 30kHz for 5min, 80g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 20℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 0.8g of spherical ADN solid is obtained.

[0054] It is detected that the particle size range of the spherical ADN solid prepared in the embodiment is between 100μm and 190μm, the average particle size is 150μm, the melting temperature is 89.2℃, the sphericity is greater than or equal to 0.93, the impact sensitivity is 16.4J, and the friction sensitivity is 64%.

[0055] Example 4

[0056] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 1g of ADN is added into 10g of dimethylbenzene, 0.01g of diphenylamine is added, stirring is carried out at 20℃ for 10min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 250W and the ultrasonic frequency is 30kHz for 5min, 80g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 20℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 0.8g of spherical ADN solid is obtained.

[0057] It is detected that the particle size range of the spherical ADN solid prepared in the embodiment is between 100μm and 190μm, the average particle size is 150μm, the melting temperature is 89.2℃, the sphericity is greater than or equal to 0.93, the impact sensitivity is 16.4J, and the friction sensitivity is 64%.

[0058] Example 5

[0059] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 1g of ADN is added into 10g of dimethylbenzene, 0.01g of diphenylamine is added, stirring is carried out at 20℃ for 10min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 250W and the ultrasonic frequency is 30kHz for 5min, 80g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 20℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 0.8g of spherical ADN solid is obtained.

[0060] The particle size of the spherical ADN solid prepared in the embodiment is in the range of 20-50 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] According to the above technical solution, the embodiment discloses a method for preparing spherical ADN at room temperature by ultrasonic treatment, which comprises the following steps: 1 g of ADN is added into 10 g of dimethylbenzene, 0.01 g of diphenylamine is added, stirring is carried out at 30°C for 20 min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 250 W and the ultrasonic frequency is 30 kHz for 5 min, 80 g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 20°C, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and dried until the weight is constant, so as to obtain 0.8 g of spherical ADN solid.

[0063] The particle size of the spherical ADN solid prepared in the embodiment is in the range of 80-150 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] According to the above technical solution, the embodiment discloses a method for preparing spherical ADN at room temperature by ultrasonic treatment, which comprises the following steps: 1.5 g of ADN is added into 20 g of dimethylbenzene, 0.02 g of N-methyl-p-nitroaniline is added, stirring is carried out at 35°C for 15 min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 400 W and the ultrasonic frequency is 40 kHz for 10 min, 130 g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 35°C, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and dried until the weight is constant, so as to obtain 1.2 g of spherical ADN solid.

[0066] The particle size of the spherical ADN solid prepared in the embodiment is in the range of 200-280 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] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 1.5g of ADN is added into 20g of dimethylbenzene, 0.02g of N-methyl-p-nitroaniline is added, stirring is carried out at 35℃ for 15min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 400W and the ultrasonic frequency is 40kHz for 15min, 130g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 35℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 1.2g of spherical ADN solid is obtained.

[0069] It is detected that the particle size range of the spherical ADN solid prepared in the embodiment is between 160μm and 220μm, the average particle size is 195μm, the melting temperature is 90.4℃, the sphericity is greater than or equal to 0.94, the impact sensitivity is 15.9J, and the friction sensitivity is 59%.

[0070] Embodiment 9

[0071] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 1.5g of ADN is added into 20g of dimethylbenzene, 0.02g of N-methyl-p-nitroaniline is added, stirring is carried out at 35℃ for 15min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 400W and the ultrasonic frequency is 40kHz for 15min, 130g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 35℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 1.2g of spherical ADN solid is obtained.

[0072] It is detected that the particle size range of the spherical ADN solid prepared in the embodiment is between 160μm and 220μm, the average particle size is 195μm, the melting temperature is 90.4℃, the sphericity is greater than or equal to 0.94, the impact sensitivity is 15.9J, and the friction sensitivity is 59%.

[0073] Embodiment 10

[0074] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 1.5g of ADN is added into 20g of dimethylbenzene, 0.02g of N-methyl-p-nitroaniline is added, stirring is carried out at 35℃ for 15min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 400W and the ultrasonic frequency is 40kHz for 15min, 130g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 35℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 1.2g of spherical ADN solid is obtained.

[0075] The particle size range of the spherical ADN solid prepared in the embodiment is between 200 μm and 290 μm, the average particle size is 245 μm, the melting temperature is 91.9 ℃, the sphericity is greater than or equal to 0.90, the impact sensitivity is 17.7 J, and the friction sensitivity is 65%.

[0076] Embodiment 11

[0077] According to the technical scheme, the embodiment discloses a method for preparing spherical ADN at room temperature by ultrasonic treatment, which comprises the following steps: adding 3.0 g of ADN into 52 g of toluene, adding 0.05 g of diphenylamine, stirring at 29 ℃ for 24 min, and then performing ultrasonic treatment under the condition that the ultrasonic power is 400 W and the ultrasonic frequency is 50 kHz for 13 min; adding 290 g of dichloromethane into a four-necked flask, and then adding the ADN solution into the dichloromethane under the stirring condition at 38 ℃; after the addition is completed, filtering the solution to obtain a filter cake; and then placing the filter cake into a dryer to dry until the weight is constant, so as to obtain 2.6 g of spherical ADN solid.

[0078] The particle size range of the spherical ADN solid prepared in the embodiment is between 70 μm and 150 μm, the average particle size is 98 μm, the melting temperature is 89.8 ℃, the sphericity is greater than or equal to 0.86, the impact sensitivity is 19.7 J, and the friction sensitivity is 60%.

[0079] Embodiment 12

[0080] According to the technical scheme, the embodiment discloses a method for preparing spherical ADN at room temperature by ultrasonic treatment, which comprises the following steps: adding 3.5 g of ADN into 76 g of toluene, adding 0.06 g of N-methyl-p-nitroaniline, stirring at 34 ℃ for 28 min, and then performing ultrasonic treatment under the condition that the ultrasonic power is 500 W and the ultrasonic frequency is 50 kHz for 15 min; adding 330 g of dichloromethane into a four-necked flask, and then adding the ADN solution into the dichloromethane under the stirring condition at 26 ℃; after the addition is completed, filtering the solution to obtain a filter cake; and then placing the filter cake into a dryer to dry until the weight is constant, so as to obtain 3.2 g of spherical ADN solid.

[0081] The particle size range of the spherical ADN solid prepared in the embodiment is between 210 μm and 300 μm, the average particle size is 257 μm, the melting temperature is 90.7 ℃, the sphericity is greater than or equal to 0.90, the impact sensitivity is 16.9 J, and the friction sensitivity is 58%.

[0082] Embodiment 13

[0083] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 3.5g of ADN is added into 76g of dimethylbenzene, 0.06g of N-methyl-p-nitroaniline is added, stirring is carried out at 34℃ for 28min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 500W and the ultrasonic frequency is 50kHz for 15min, 330g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 40℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 3.2g of spherical ADN solid is obtained.

[0084] It is detected that the particle size range of the spherical ADN solid prepared in the embodiment is between 140μm and 190μm, the average particle size is 164μm, the melting temperature is 91.8℃, the sphericity is greater than or equal to 0.84, the impact sensitivity is 18.2J, and the friction sensitivity is 61%.

[0085] Embodiment 14

[0086] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 3.5g of ADN is added into 76g of dimethylbenzene, 0.06g of N-methyl-p-nitroaniline is added, stirring is carried out at 34℃ for 28min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 500W and the ultrasonic frequency is 50kHz for 15min, 330g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 40℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 3.2g of spherical ADN solid is obtained.

[0087] It is detected that the particle size range of the spherical ADN solid prepared in the embodiment is between 140μm and 190μm, the average particle size is 164μm, the melting temperature is 91.8℃, the sphericity is greater than or equal to 0.84, the impact sensitivity is 18.2J, and the friction sensitivity is 61%.

[0088] Embodiment 14

[0089] According to the technical scheme, the embodiment discloses a preparation method of spherical ADN at normal temperature and under ultrasonic condition, which comprises the following steps: 3.5g of ADN is added into 76g of dimethylbenzene, 0.06g of N-methyl-p-nitroaniline is added, stirring is carried out at 34℃ for 28min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 500W and the ultrasonic frequency is 50kHz for 15min, 330g of dichloromethane is added into a four-necked flask, the ADN solution is added dropwise into the dichloromethane under the stirring condition at 40℃, the solution is filtered after the dropwise addition is completed, and a filter cake is obtained; the filter cake is placed into a dryer, and drying is carried out until the weight is constant, so that 3.2g of spherical ADN solid is obtained.

[0090] The particle size of the spherical ADN solid prepared in the embodiment is in the range of 260 μm to 330 μm, the average particle size is 292 μm, the melting temperature is 90.4 ℃, the sphericity is greater than or equal to 0.89, the impact sensitivity is 18.1 J, and the friction sensitivity is 57%.

[0091] As can be seen from Examples 1 to 15,

[0092] The method of the present application 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 component ratio of raw materials and the reaction conditions such as reaction temperature, ultrasonic power, ultrasonic frequency and dropping temperature, the controllable classification of the spherical particle size can be realized. The method of the present application is easy to operate and has low cost. The particle size of the prepared ammonium dinitramide is controlled in the range of 10 μm to 500 μm, the particle size range is larger, the applicability is wider, the melting temperature is 89.2 to 92.30 ℃, the sphericity is greater than or equal to 0.8, the impact sensitivity is 15.2 J to 20.0 J, the friction sensitivity is 74% to 81%, and the performance of the product is obviously improved.

[0093] Comparative Example 1

[0094] The present comparative example discloses a preparation method of spherical ammonium dinitramide. The raw material components and the ratio used in the present comparative example are the same as those in Example 1. The difference lies in that no ultrasonic treatment is used in the preparation process of the present comparative example. Specifically, 5 g of ammonium dinitramide (ADN) is added to 100 g of toluene, and 0.1 g of N-methyl-p-nitroaniline is added. The mixture is stirred at 25 ℃ for 30 min. Then, 500 g of dichloromethane is added to a four-necked flask. The ultrasonic-treated ammonium dinitramide solution is added dropwise to the dichloromethane under stirring at 30 ℃. After the dropping is completed, the solution is filtered to obtain a filter cake. The filter cake is placed in a dryer and dried to constant weight to obtain 4.4 g of spherical ADN solid.

[0095] The particle size of the spherical ADN solid prepared in the present comparative example is in the range of 550 μm to 650 μm, the average particle size is 597 μm, the melting temperature is 90.07 ℃, the sphericity is greater than or equal to 0.50, the impact sensitivity is 9.4 J, and the friction sensitivity is 73%.

[0096] The present comparative example prepares spherical ammonium dinitramide with large particle size. The sphericity, impact sensitivity and friction sensitivity of the spherical ammonium dinitramide prepared in the present comparative example are all not as good as those of the spherical ammonium dinitramide prepared by using the method of the present application.

[0097] Comparative Example 2

[0098] The comparative example discloses a spherical ADN preparation method at normal temperature by ultrasonic treatment. The raw material components and the ratio used in the comparative example are the same as those in Example 1. The difference lies in that the ultrasonic treatment conditions used in step 2 of the comparative example are different. In the comparative example, the ultrasonic treatment is performed under the conditions of an ultrasonic power of 1000 W and an ultrasonic frequency of 60 kHz for 10 min. Finally, spherical ADN solid 4.6 g is obtained.

[0099] It is detected that the particle size range of the spherical ADN solid prepared in the comparative example is 300 μm-450 μm, the average particle size is 376 μm, the melting temperature is 89.71 ℃, the sphericity is greater than or equal to 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 ADN prepared in the comparative example are all not as good as those of the spherical ADN prepared by the method of the application.

[0101] Comparative Example 3

[0102] The comparative example discloses a spherical ADN preparation method at normal temperature by ultrasonic treatment. The preparation method used in the comparative example is the same as that in Example 1. The difference lies in that the organic solvent used in the comparative example is benzene. In the comparative example, spherical ADN solid 4.0 g is finally obtained.

[0103] It is detected that the particle size range of the spherical ADN solid prepared in the comparative example is 480 μm-650 μm, the average particle size is 557 μm, the melting temperature is 93.40 ℃, the sphericity is greater than or equal to 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 ADN prepared in the comparative example are all not as good as those of the spherical ADN prepared by the method of the application.

[0105] Comparative Example 4

[0106] The comparative example discloses a spherical ADN preparation method at normal temperature by ultrasonic treatment. The main raw material components and the preparation method used in the comparative example are the same as those in Example 1. The difference lies in that the auxiliary agent selected in the comparative example is sodium p-toluenesulfonate. In the comparative example, spherical ADN solid 4.9 g is obtained.

[0107] It is detected that the particle size range of the spherical ADN solid prepared in the comparative example is 270 μm-400 μm, the average particle size is 349 μm, the melting temperature is 88.44 ℃, the sphericity is greater than or equal to 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 ADN prepared in the comparative example are all not as good as those of the spherical ADN prepared by the method of the application.

[0109] Comparative Example 5

[0110] The embodiment discloses a preparation method of spherical ADN at normal temperature by ultrasonic. Main raw material components and a preparation method of the comparative example are same to those of the embodiment 1, and the only difference is that dichloromethane is replaced by acetone in the comparative example. Finally, spherical ADN solid 4.4 g is prepared.

[0111] It is detected that the particle size range of the spherical ADN solid prepared in the comparative example is 250-550 μm, the average particle size is 360 μm, the melting temperature is 91.66 DEG C, the sphericity is greater than or equal to 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 ADN prepared in the comparative example are all worse than those of the spherical ADN prepared by the method of the embodiment.

[0113] Comparative Example 6

[0114] The embodiment discloses a preparation method of spherical ADN at normal temperature by ultrasonic. 5 g of ADN is added into 100 g of toluene, and 0.1 g of N-methyl-p-nitroaniline is added, stirring is carried out at 25 DEG C for 30 min, ultrasonic treatment is carried out under the condition that the ultrasonic power is 300 W and the ultrasonic frequency is 40 kHz for 10 min, 500 g of dichloromethane is added into a constant-pressure dropping funnel, the dichloromethane is added into the ADN solution treated by ultrasonic under the condition that the stirring temperature is 30 DEG C, the solution is filtered after the addition is completed, and the filter cake is obtained. The filter cake is placed into a dryer, and is dried until the weight is constant, so as to obtain 4.6 g of spherical ADN solid.

[0115] It is detected that the particle size range of the spherical ADN solid prepared in the comparative example is 400-550 μm, the average particle size is 476 μm, the melting temperature is 91.47 DEG C, the sphericity is greater than or equal to 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 ADN prepared in the comparative example are worse than those of the embodiment 1.

[0117] The preferred embodiments of the disclosure are described in detail above with reference to the drawings, but the disclosure is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the disclosure within the technical concept of the disclosure, and the simple modifications all belong to the protection range of the disclosure.

[0118] It should also be noted that various technical features described in the above detailed description are capable of being combined in any suitable manner and that the disclosure is not limited to the specific combinations set out in the above detailed description.

Claims

1. A process for the ultrasonic production of spherical diammonium nitroxyIamide, characterized in that, The method comprises the following steps: Step 1, adding ammonium dinitramide particles and an auxiliary agent into an organic solvent, stirring at a temperature of 20-35°C for 10-30 min to obtain an ammonium dinitramide solution; Step 2, placing the ammonium dinitramide solution into an ultrasonic instrument, and ultrasonically treating for 5-15 min at a set ultrasonic power and ultrasonic frequency; Step 3, under stirring, adding the ultrasonically treated ammonium dinitramide solution into dichloromethane at a set dropping temperature, and filtering and drying after the addition is completed to obtain the product; 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). The organic solvent is selected from one or both of toluene and xylene. The auxiliary agent is N-methyl-p-nitroaniline or diphenylamine. The ultrasonic power is 10-800 W, and the ultrasonic frequency is 20-50 Hz.

2. The process for the ultrasonic preparation of spherical ammonium dinitramide according to claim 1, characterized in that, The dropping temperature in Step 3 is 20-40°C.

3. The spherical ammonium dinitramide prepared by the preparation method of claim 1 or claim 2.

4. The spherical ammonium dinitramide of claim 3, wherein, The particle size of the ammonium dinitramide is 10-500 µm, the melting temperature is 89.2-92.30°C, the sphericity is ≥0.8, the impact sensitivity is 15.2-20.0 J, and the friction sensitivity is 74%-81%.

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