A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide

Abstract

The present invention is a method for preparing spherical crystals of 3,4-dinitrofurazan-based furazan oxide, and relates to the technical field of energetic crystal materials. The method comprises: 1) fully dissolving 3,4-dinitrofurazan-based furazan oxide, a crystallization solvent, and a crystallization additive; 2) lowering the temperature while stirring to form a supersaturated solution, and keeping the temperature for a period of time when a crystal nucleus appears; 3) continuing to lower the temperature while stirring until it drops to room temperature; 4) filtering, washing, and drying to obtain the product. The DNTF crystals obtained by the present invention have a very high degree of sphericity, a regular crystal morphology, a smooth surface, few transparent defects inside the crystal, and good fluidity. The process of the present invention is simple, easy to control, and the crystallization mother liquor can be recycled, which is conducive to reducing the pollution of the organic solvent to the environment, is low in cost, safe and reliable, and is suitable for industrial mass production.

Description

Technical Field

[0001] The invention relates to the technical field of energetic crystal materials, in particular to a method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide. Background Art

[0002] 3,4-Dinitrofurazanyl furazan oxide (DNTF) is an important new type of high-energy explosive with great power, moderate sensitivity, good thermal stability, and good application prospects in the field of energetic materials. Since it was synthesized in China in 2002, it has attracted great attention due to its high energy characteristics. The structural formula of DNTF is as follows:

[0003]

[0004] DNTF has high density, high detonation velocity (higher than HMX), high detonation heat, and its comprehensive performance is better than that of octogenin (HMX) and close to that of CL-20. "Research on the Performance and Application of High Energy Density Material 3,4-Furazanyl Oxide Furazan" (Acta Armamentarii, No. 2, 2004, P155-158) reported on DNTF single explosive. The document used acetic acid / water system to recrystallize DNTF. The resulting crystals had high acidity, large particle size, high impact sensitivity (96%), and a relative density of 95%. Patent ZL201510100531.2 "A high-quality single-substance explosive recrystallization method" discloses a method for preparing a high-quality DNTF-based mixed explosive, which has high molding density and low mechanical sensitivity. The high-quality DNTF is prepared by a solvent-non-solvent method, but the specific crystal morphology is not mentioned; Patent ZL201811031142.9 "A low shock wave sensitivity DNTF and its preparation method" discloses a method for preparing low shock wave sensitivity DNTF by mixing calcium stearate and sodium dodecyl sulfate, which are substances with low shock sensitivity, and does not involve the crystal morphology of DNTF itself. In the existing DNTF crystallization process research, there are few studies on the preparation process of spherical crystals and the results are not satisfactory.

[0005] For solid explosives, the physical form of explosives refers to the size, shape, internal defects, etc. of the explosives. Compared with needle-shaped, flake-shaped, and rod-shaped crystals, spherical crystals have a higher surface area to volume ratio, better free flow characteristics, and higher bulk density. Preparing them into mixed explosives can greatly increase the charge density, thereby improving the detonation performance of the charge (Zhao Xue, Rui Jiuhou, Feng Shunshan. Effect of RDX particle morphology on the performance of RDX-based melt-cast explosives, Journal of Nanjing University of Science and Technology (Natural Science Edition), 2011, 35 (05): 714-716.). In addition, spherical explosive crystals are dense, have fewer internal defects, and may form fewer explosions, and have lower mechanical sensitivity than other shapes (Zhao Xue, Rui Jiuhou, Feng Shunshan. Preparation of spherical RDX by recrystallization, Journal of Beijing Institute of Technology, 2011, 31 (1): 5-7). Therefore, obtaining uniform particle size, regular shape, and spherical shape is an important way to improve the performance of single-element explosives and mixed explosives, and is also an important part of the preparation of single-element explosives. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide in order to obtain the best DNTF bombardment, safety and application performance. The core content of the method is to obtain highly spherical DNTF crystals by cooling and crystallizing the raw material DNTF.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide comprises the following steps:

[0009] 1) Add 3,4-dinitrofurazanyl furazan oxide, crystallization solvent and crystallization additive into the crystallization kettle and fully dissolve them. The initial temperature in the crystallization kettle is set to 50-80°C;

[0010] 2) Lower the temperature in the crystallization kettle while stirring to form a supersaturated solution. When crystal nuclei appear, keep the temperature for 1 to 3 hours;

[0011] 3) After the insulation is completed, continue to lower the temperature in the crystallization kettle while stirring until it drops to room temperature;

[0012] 4) filtering, washing and drying the material in the crystallization kettle to obtain the highly spherical 3,4-dinitrofurazanyl furazan oxide spherical crystals.

[0013] As a preferred technical solution, in step 1), the concentration of the solution formed by 3,4-dinitrofurazanyl furazan oxide and the crystallization solvent is 0.03-0.2 g / mL.

[0014] As a preferred technical solution, in step 1), the amount of the crystallization additive is 0.01% to 3% of the mass of 3,4-dinitrofurazanyl furan oxide.

[0015] As a preferred technical solution, in step 1), the crystallization solvent is a pure solvent of n-propanol, isopropanol or n-butanol.

[0016] As a preferred technical solution, in step 1), the crystallization solvent is a binary mixed solvent consisting of n-propanol, isopropanol or n-butanol and water.

[0017] As a preferred technical solution, in step 1), the crystallization additive is Span 20, Span 80, Span 80, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600 or polyethylene glycol 4000.

[0018] As a preferred technical solution, in step 2) and step 3), the cooling rate for reducing the temperature in the crystallization kettle is 0.1~1°C / min.

[0019] In order to obtain highly spherical DNTF, the present invention utilizes the principle that "in addition to the unit cell structure of the solute itself, the crystal growth environment is an important factor in determining the crystal morphology" and provides a method for preparing spherical DNTF crystals under preferred solvents, additives and processes.

[0020] The present invention adopts a cooling crystallization method, which is to cool the solution to make it supersaturated and precipitate crystals, and utilizes the principle that "in addition to the unit cell structure of the solute itself, the crystal growth environment is an important factor in determining the crystal morphology", and finally obtains highly spherical 3,4-dinitrofuroxanyl furazan oxide spherical crystals.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The obtained crystals have a very high degree of sphericity, regular crystal morphology, smooth surface, few transparent defects inside the crystals, and good fluidity.

[0023] 2) The spheroidization process is simple and easy to control. The crystallization mother liquor can be recycled, which is beneficial to reduce the pollution of organic solvents to the environment. It is low-cost, safe and reliable, and suitable for industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings herein are used to provide further explanation of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 This is an optical microscope image of 3,4-dinitrofurazanyl furazan oxide, a raw material used in the present invention.

[0026] Figure 2 This is an optical microscope image of the spherical crystals of 3,4-dinitrofurazanyl furazan oxide prepared in the present invention. DETAILED DESCRIPTION

[0027] In order to make those skilled in the art better understand the present invention, the present invention is further clearly and completely described below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the absence of conflict, the features in the embodiments and examples of this application can be combined with each other.

[0028] The present invention provides a method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide, which comprises the following steps:

[0029] 1) Add 3,4-dinitrofurazanyl furazan oxide, crystallization solvent and crystallization additive into the crystallization kettle and fully dissolve them. The initial temperature in the crystallization kettle is set to 50-80°C;

[0030] Among them, the concentration of the solution formed by 3,4-dinitrofuroxanyl furazan oxide and the crystallization solvent is 0.03~0.2g / mL, the crystallization solvent is a pure solvent of n-propanol, isopropanol or n-butanol, or a binary mixed solvent composed of n-propanol, isopropanol or n-butanol and water; the amount of the crystallization additive is 0.01%~3% of the mass of 3,4-dinitrofuroxanyl furazan oxide, and the crystallization additive is Sban 20, Sban 80, Sban 80, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600 or polyethylene glycol 4000.

[0031] 2) Lower the temperature in the crystallization kettle while stirring at a rate of 0.1~1℃ / min to form a supersaturated solution. When crystal nuclei appear, keep the temperature for 1~3 hours.

[0032] 3) After the insulation is completed, continue to lower the temperature in the crystallization kettle while stirring at a cooling rate of 0.1~1℃ / min until it reaches room temperature.

[0033] 4) filtering, washing and drying the material in the crystallization kettle to obtain the highly spherical 3,4-dinitrofurazanyl furazan oxide spherical crystals.

[0034] Figure 1 This is an optical microscope image of the raw material DNTF used in step 1) of the present invention, Figure 2 This is an optical microscope image of the spherical crystals of 3,4-dinitrofurazanyl furazan oxide prepared in step 4) of the present invention. As can be seen from the image, the 3,4-dinitrofurazanyl furazan oxide product obtained after crystallization changes from the powder before crystallization to crystals, and the crystals have high sphericity, smooth surface, transparent crystals, and few internal defects.

[0035] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described and illustrated in conjunction with several specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All equivalent implementation methods or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention. Example 1

[0036] A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide comprises the following steps:

[0037] 1) Measure 40 mL of n-propanol and 2 mL of water, weigh 90% polyethylene glycol 600 ethanol solution with a mass of 0.3% of the mass of 3,4-dinitrofurazanyl furazan oxide, add them to the crystallization kettle in sequence, and then weigh 5.13 g of raw material 3,4-dinitrofurazanyl furazan oxide and add them to the crystallization kettle, stir them fully at a speed of 300 r / min, heat the temperature in the crystallization kettle to 70°C, so that the raw material 3,4-dinitrofurazanyl furazan oxide is fully dissolved, and keep it for 30 minutes;

[0038] 2) Slowly lower the temperature in the crystallization kettle while stirring, the stirring speed is 300r / min, the cooling rate is 0.7℃ / min, and when the crystal nucleus appears, keep it for 3 hours;

[0039] 3) After the insulation is completed, continue to lower the temperature in the crystallization kettle while stirring, the stirring speed is 300r / min, and the cooling rate is 0.7℃ / min, until the temperature of the crystallization kettle drops to room temperature;

[0040] 4) filtering, washing and drying the material in the crystallization kettle to obtain the spherical crystals of 3,4-dinitrofurazanyl furazan oxide. Example 2

[0041] A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide comprises the following steps:

[0042] 1) Take 100 mL of isopropanol and weigh 90% polyethylene glycol 600 ethanol solution with a mass of 0.5% of the mass of 3,4-dinitrofurazanyl furazan oxide; add them to the crystallization kettle in sequence, and then weigh 5.10 g of the raw material 3,4-dinitrofurazanyl furazan oxide, add them to the crystallization kettle, stir them fully at a speed of 300 r / min, heat the crystallization kettle to 70°C, so that the raw material 3,4-dinitrofurazanyl furazan oxide is fully dissolved, and balance for 30 minutes;

[0043] 2) Slowly lower the temperature of the crystallization kettle while stirring, the stirring speed is 300 r / min, the cooling rate is 0.5℃ / min, and when the crystal nucleus appears, keep it for 2 hours;

[0044] 3) After the insulation is completed, continue to lower the temperature in the crystallization kettle while stirring, with a stirring speed of 300 r / min and a cooling rate of 0.5℃ / min until the temperature in the crystallization kettle drops to room temperature;

[0045] 4) filtering, washing and drying the material in the crystallization kettle to obtain the spherical crystals of 3,4-dinitrofurazanyl furazan oxide. Example 3

[0046] A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide comprises the following steps:

[0047] 1) Take 100 mL of n-butanol and weigh 90% polyethylene glycol 600 ethanol solution with a mass of 1% of the mass of 3,4-dinitrofurazanyl furazan oxide; add them to the crystallization kettle in sequence, then weigh 10.10 g of the raw material 3,4-dinitrofurazanyl furazan oxide, add it to the crystallization kettle, stir it fully at a speed of 300 r / min, heat the crystallization kettle to 60°C, so that the raw material 3,4-dinitrofurazanyl furazan oxide is fully dissolved, and balance for 30 minutes;

[0048] 2) Slowly lower the temperature in the crystallization kettle while stirring, the stirring speed is 300r / min, the cooling rate is 0.8℃ / min, and when the crystal nucleus appears, keep it for 2 hours;

[0049] 3) After the insulation is completed, continue to lower the temperature in the crystallization kettle while stirring, the stirring speed is 300r / min, and the cooling rate is 0.8℃ / min, until the temperature in the crystallization kettle drops to room temperature;

[0050] 4) filtering, washing and drying the material in the crystallization kettle to obtain the spherical crystals of 3,4-dinitrofurazanyl furazan oxide. Example 4

[0051] A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide comprises the following steps:

[0052] 1) Measure 40 mL of n-butanol and 2 mL of water, weigh 90% polyethylene glycol 600 ethanol solution with a mass of 0.01% of the mass of 3,4-dinitrofurazanyl furazan oxide, add them to the crystallization kettle in sequence, and then weigh 2.18 g of raw material 3,4-dinitrofurazanyl furazan oxide and add them to the crystallization kettle, stir them fully at a speed of 300 r / min, heat the temperature in the crystallization kettle to 50°C, so that the raw material 3,4-dinitrofurazanyl furazan oxide is fully dissolved, and keep it for 30 minutes;

[0053] 2) Slowly lower the temperature in the crystallization kettle while stirring, the stirring speed is 300r / min, the cooling rate is 1.0℃ / min, and when the crystal nucleus appears, keep it for 1 hour;

[0054] 3) After the insulation is completed, continue to lower the temperature in the crystallization kettle while stirring, with a stirring speed of 300r / min and a cooling rate of 1.0℃ / min, until the temperature of the crystallization kettle drops to room temperature;

[0055] 4) filtering, washing and drying the material in the crystallization kettle to obtain the spherical crystals of 3,4-dinitrofurazanyl furazan oxide. Example 5

[0056] A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide comprises the following steps:

[0057] 1) Take 100 mL of n-propanol and weigh a 2% Siban 80 solution of 3,4-dinitrofurazanyl furazan oxide; add them to the crystallization kettle in sequence, then weigh 14.05 g of the raw material 3,4-dinitrofurazanyl furazan oxide, add them to the crystallization kettle, stir them fully at a speed of 300 r / min, heat the crystallization kettle to 80°C, so that the raw material 3,4-dinitrofurazanyl furazan oxide is fully dissolved, and balance for 30 minutes;

[0058] 2) Slowly lower the temperature in the crystallization kettle while stirring, the stirring speed is 300r / min, the cooling rate is 0.1℃ / min, and when the crystal nucleus appears, keep it for 2 hours;

[0059] 3) After the insulation is completed, continue to lower the temperature in the crystallization kettle while stirring, the stirring speed is 300r / min, and the cooling rate is 0.1℃ / min, until the temperature in the crystallization kettle drops to room temperature;

[0060] 4) filtering, washing and drying the material in the crystallization kettle to obtain the spherical crystals of 3,4-dinitrofurazanyl furazan oxide.

[0061] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide, characterized in that: The steps include: 1) Add 3,4-dinitrofurazanyl furazan oxide, crystallization solvent, and crystallization additive into a crystallization kettle for full dissolution, and set the initial temperature in the crystallization kettle to 50-80°C; wherein, the concentration of the solution formed by 3,4-dinitrofurazanyl furazan oxide and the crystallization solvent is 0.03-0.2 g / mL, the crystallization solvent is a pure solvent of n-propanol, isopropanol or n-butanol, or a binary mixed solvent consisting of n-propanol, isopropanol or n-butanol and water, the crystallization additive is Span 80 or polyethylene glycol 600, and the amount of the crystallization additive is 0.01%-3% of the mass of 3,4-dinitrofurazanyl furazan oxide; 2) Lower the temperature in the crystallization kettle while stirring to form a supersaturated solution. When crystal nuclei appear, keep the temperature for 1 to 3 hours; 3) After the insulation is completed, continue to lower the temperature in the crystallization kettle while stirring until it drops to room temperature; 4) filtering, washing and drying the material in the crystallization kettle to obtain the spherical crystals of 3,4-dinitrofurazanyl furazan oxide.

2. A method for preparing spherical crystals of 3,4-dinitrofurazanyl furazan oxide according to claim 1, characterized in that: In step 2) and step 3), the cooling rate for reducing the temperature in the crystallization kettle is 0.1~1℃ / min.

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