A method and system for the stable preparation of γ-HMX at room temperature based on microfluidic technology

Abstract

The invention discloses a method and system for preparing γ-HMX stably at room temperature based on microfluidic technology. The preparation method comprises the following steps: raw material HMX is dissolved in DMSO as a solvent phase, and water is a non-solvent phase; the solvent phase and the non-solvent phase are injected into a crystallization chip for mixing; γ-HMX particles are rapidly precipitated to form a suspension, which is filtered and collected after flowing out; the concentration of the solvent phase is 100-300 g / L; the flow rate of the solvent phase is 1-20 ml / min, the flow rate of the non-solvent phase is 10-100 ml / min, and the flow ratio of the non-solvent phase to the solvent phase is (10-100): 1. The method of the invention can obtain pure γ-type HMX that is stably present at room temperature, and the preparation process can be carried out at room temperature without temperature control.

Description

Technical Field

[0001] The invention belongs to the technical field of energetic material preparation, and in particular relates to a method and system for stably preparing γ-HMX at room temperature based on microfluidic technology. Background Art

[0002] Octogen (HMX) is considered to be one of the single explosives with the best comprehensive performance at present due to its excellent properties such as high density, high detonation velocity, high detonation pressure and good chemical stability. It is widely used in weapon equipment systems. Between room temperature and melting point, HMX has four crystal forms: α-, β-, γ-, and δ-. Among them, the γ crystal form is metastable at room temperature. The preparation of γ-HMX requires a relatively high cooling rate. Generally, β-HMX is dissolved in a 50% acetic acid solution and heated, then cooled in ice water for 5 minutes, and the solution temperature is reduced to 20°C within 1.5 to 2 minutes by sufficient stirring. Many studies have also reported the phenomenon of γ-HMX appearing after recrystallization, but they are all polymorphic mixtures, and the preparation of pure γ-HMX has not been reported. Summary of the invention

[0003] The present invention provides a method and system for stably preparing γ-HMX at room temperature based on microfluidic technology. The method can realize the preparation of γ-HMX that exists stably at room temperature.

[0004] To achieve the above object, the technical solution adopted by the present invention includes:

[0005] A room-temperature stable preparation method of γ-HMX based on microfluidic technology comprises the following steps: raw material HMX is dissolved in DMSO as a solvent phase, and water is used as a non-solvent phase; the solvent phase and the non-solvent phase are injected into a crystallization chip for mixing; γ-HMX particles are precipitated to form a suspension, which is filtered and collected after flowing out; the concentration of the solvent phase is 100-300 g / L; the flow rate of the solvent phase is 1-20 ml / min, the flow rate of the non-solvent phase is 10-100 ml / min, and the flow ratio of the non-solvent phase to the solvent phase is (10-100):1.

[0006] Optionally, the preparation process is carried out at room temperature.

[0007] Optionally, the concentration of the solvent phase is 100 g / L, the flow rate is 1 mL / min, and the flow rate of the non-solvent phase is 80 mL / min.

[0008] Optionally, the concentration of the solvent phase is 150 g / L, the flow rate is 5 mL / min, and the flow rate of the non-solvent phase is 100 mL / min.

[0009] Optionally, the concentration of the solvent phase is 200 g / L, the flow rate is 5 mL / min, and the flow rate of the non-solvent phase is 50 mL / min.

[0010] A room-temperature stable preparation system of γ-HMX based on microfluidic technology, the system is used to implement any room-temperature stable preparation method of γ-HMX based on microfluidic technology described in the present invention; specifically comprising: arranging a solvent phase injection pump and a non-solvent phase injection pump, the two are respectively connected to set a crystallization chip; the crystallization chip is vortex-shaped, heart-shaped or T-shaped.

[0011] A method for preparing γ-HMX stably at room temperature based on microfluidic technology is implemented by using the γ-HMX stably at room temperature based on microfluidic technology of the present invention, and specifically comprises:

[0012] Step 1: Prepare a DMSO solution with a HMX concentration of 100-300 g / L; connect the solvent phase injection pump and the non-solvent phase injection pump to the crystallization chip, and then connect the crystallization chip to the sample collection bottle;

[0013] Step 2: Set the flow rate of the solvent phase to 1-20 mL / min, the flow rate of the non-solvent phase to 10-100 mL / min, and the flow ratio of the non-solvent phase to the solvent phase to be (10-100):1; pump the solvent phase and the non-solvent phase into the crystallization chip respectively by the solvent phase injection pump and the non-solvent phase injection pump;

[0014] Step 3: The solvent phase and the non-solvent phase are mixed in the crystallization chip and HMX particles are quickly precipitated to form a suspension. The precipitate in the suspension is γ-HMX, which is collected by filtration.

[0015] Optionally, the concentration of the solvent phase is 100 g / L, the flow rate is 1 mL / min, and the flow rate of the non-solvent phase is 80 mL / min.

[0016] Optionally, the concentration of the solvent phase is 150 g / L, the flow rate is 5 mL / min, and the flow rate of the non-solvent phase is 100 mL / min.

[0017] Optionally, the concentration of the solvent phase is 200 g / L, the flow rate is 5 mL / min, and the flow rate of the non-solvent phase is 50 mL / min.

[0018] Beneficial effects of the present invention:

[0019] (1) The method of the present invention can be used to obtain pure γ-type HMX, and the sample size is at the micro-nano level;

[0020] (2) Compared with other existing γ-HMX preparation methods, the method of the present invention does not require external temperature control, and the preparation process is carried out at room temperature;

[0021] (3) The γ-HMX prepared by the present invention can exist stably at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0023] Figure 1 Schematic diagram of the room-temperature stable preparation system of γ-HMX;

[0024] Figure 2 is the SEM picture of the prepared γ-HMX;

[0025] Figure 3 is the XRD pattern of the prepared γ-HMX. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the embodiments.

[0027] The present invention utilizes a solvent-nonsolvent method to build a microfluidic technology platform to prepare γ-type HMX powder. The method has a simple process flow and can produce γ-HMX that is stable at room temperature without external temperature control.

[0028] The present invention discloses a method for preparing γ-HMX at room temperature in a stable manner based on microfluidic technology, comprising: dissolving the raw material HMX in DMSO as a solvent phase, and using deionized water as a non-solvent phase. A driving device injects the solvent phase and the non-solvent phase into a crystallization chip at a certain flow rate for mixing, and γ-HMX particles are rapidly precipitated to form a suspension, which is then filtered and collected after flowing out.

[0029] In the above method, the solvent phase concentration is 100-300 g / L, the solvent phase flow rate range is 1-20 ml / min, the non-solvent phase flow rate range is 10-100 ml / min, and the flow ratio of the non-solvent phase to the solvent phase is (10-100): 1. The preparation process does not require external temperature control, and pure γ-HMX that is stable at room temperature can be obtained.

[0030] In the embodiments of the present disclosure

[0031] In a preferred embodiment, the concentration of the fast solvent phase is 100 g / L, the flow rate is 1 mL / min, and the flow rate of the non-solvent phase is 80 mL / min.

[0032] In a preferred embodiment, the solvent phase concentration is 200 g / L, the flow rate is 5 mL / min, and the non-solvent phase flow rate is 100 mL / min.

[0033] In a preferred embodiment, the concentration of the fast solvent phase is 300 g / L, the flow rate is 5 mL / min, and the flow rate of the non-solvent phase is 50 mL / min.

[0034] Combination Figure 1The room-temperature stable preparation system of γ-HMX of the present invention is used to realize the room-temperature stable preparation method of γ-HMX based on microfluidic technology of the present invention; the system is provided with a two-phase injection pump and a crystallization chip for pumping in the solvent phase and the non-solvent phase respectively.

[0035] Optionally, the crystallization hybrid chip is vortex-shaped, heart-shaped, or T-shaped.

[0036] Preferably, the room-temperature stable preparation method of γ-HMX based on microfluidic technology is implemented by using the room-temperature stable preparation system of γ-HMX of the present invention, and specifically comprises:

[0037] Step 1: Prepare a DMSO solution with a HMX concentration of 100-300 g / L; connect the solvent phase injection pump and the non-solvent phase injection pump to the crystallization chip, and connect the crystallization mixing chip to the sample collection bottle;

[0038] Step 2: Set the flow rate of the solvent phase to 1-20 mL / min, the flow rate of the non-solvent phase to 10-100 mL / min, and the flow ratio of the non-solvent phase to the solvent phase to (10-100):1; use the solvent phase injection pump and the non-solvent phase injection pump to pump the solvent phase and the non-solvent phase into the crystallization chip respectively.

[0039] Step 3: The solvent phase and the non-solvent phase are fully mixed in the crystallization chip and HMX particles are quickly precipitated to form a suspension. The precipitate in the suspension is γ-HMX, which is collected by filtration.

[0040] The technical solution of the present invention is described in detail below with reference to specific embodiments. Unless otherwise specified, the solvents or methods used are commonly used in the art or are commercially available.

[0041] Embodiment 1:

[0042] according to Figure 1 Device, choose heart-shaped crystallization chip. Weigh 5g of raw material HMX and dissolve it in 50mL DMSO solvent as solvent phase, and use deionized water as non-solvent. Set the flow rate of solvent phase injection pump to 1mL / min, and the flow rate of non-solvent phase injection pump to 80mL / min, so that the solvent phase and non-solvent phase are fully mixed in the crystallization chip and HMX particles are quickly precipitated to form a suspension. The precipitate in the suspension is γ-HMX collected by filtration.

[0043] Embodiment 2:

[0044] according to Figure 1The device uses a vortex crystallization chip. Weigh 10g of raw material HMX and dissolve it in 50mL DMSO solvent as the solvent phase, and use deionized water as the non-solvent. Set the solvent phase injection pump flow rate to 5mL / min and the non-solvent phase injection pump flow rate to 100mL / min, so that the solvent phase and the non-solvent phase are fully mixed in the crystallization chip and HMX particles are quickly precipitated to form a suspension. The precipitate in the suspension is γ-HMX, which is collected by filtration.

[0045] Embodiment 3:

[0046] according to Figure 1 The device uses a T-type crystallization chip. Weigh 15g of raw material HMX and dissolve it in 50mL DMSO solvent as the solvent phase, and use deionized water as the non-solvent. Set the solvent phase injection pump flow rate to 5mL / min and the non-solvent phase injection pump flow rate to 50mL / min, so that the solvent phase and the non-solvent phase are fully mixed in the crystallization chip and HMX particles are quickly precipitated to form a suspension. The precipitate in the suspension is γ-HMX, which is collected by filtration.

[0047] Sample characterization analysis:

[0048] Figure 2 (a-c) are scanning electron microscope photos of the samples obtained in Examples 1-3. It can be clearly seen from the pictures that the sample particles are short rod-shaped, with a flat and smooth surface, no edges or corners, and a size at the micro-nano level.

[0049] Figure 3 The X-ray powder diffraction pattern of the sample obtained in Example 1. The sample obtained by the literature method is a blend of β and γ. The position and relative intensity of the diffraction peaks of the sample obtained by the method of the present invention are basically consistent with the PDF standard data of γ-type HMX crystals. It shows that the microfluidic system can improve the crystallization rate through efficient mixing at microscale to obtain pure γ-HMX that is stable at room temperature. This is mainly because, on the one hand, if the crystallization rate is too fast, it may lead to the generation of crystal surface defects, forming a huge step development and a short rod shape, which will produce γ-HMX; on the other hand, the selected solvent DMSO will release heat when it is miscible with deionized water, resulting in the crystallization heat generated by crystallization cannot be quickly diffused and local temperature rise. Due to the different degrees of change in the Gibbs free energy of HMX crystals of different crystal forms, it is possible to generate metastable crystal form γ. After measurement, the data in Table 1 show that the density of the sample obtained in Example 1 is significantly improved compared with the literature method. Density is the basic condition to ensure high-level energy output, and continuously improving the density of energetic materials is also a focus of research.

[0050] Table 1

[0051]

[0052] The above is a detailed discussion of the best embodiment in conjunction with the accompanying drawings, which is not intended to limit the present invention. The specific technical features described above can be combined in any suitable form without contradiction, and the present invention does not go into details one by one. Any person skilled in the art may adopt simple modifications or modifications such as arbitrary combination or equivalent replacement of the technical solution without departing from the scope of the technical solution, which does not affect the essence of the technical solution and still falls within the protection scope of the technical solution represented by the embodiments of the present invention.

Claims

1. A method for preparing γ-HMX stably at room temperature based on microfluidic technology, characterized in that: This is achieved using a room-temperature stable preparation system for γ-HMX based on microfluidics technology. The preparation system specifically includes: A solvent phase injection pump and a non-solvent phase injection pump are provided, and the two are respectively connected to a crystallization chip; the crystallization chip is a vortex type, a heart type or a T type; The preparation method specifically comprises: The raw material HMX is dissolved in DMSO as the solvent phase, water is the non-solvent phase, and the preparation process is carried out at room temperature; Step 1: Prepare a DMSO solution with a HMX concentration of 100-300 g / L; connect the solvent phase injection pump and the non-solvent phase injection pump to the crystallization chip, and then connect the crystallization chip to the sample collection bottle; Step 2: Set the flow rate of the solvent phase to 1-20 mL / min, the flow rate of the non-solvent phase to 10-100 mL / min, and the flow ratio of the non-solvent phase to the solvent phase to be (10-100):1; use the solvent phase injection pump and the non-solvent phase injection pump to pump the solvent phase and the non-solvent phase into the crystallization chip respectively; Step 3: The solvent phase and the non-solvent phase are mixed in the crystallization chip and HMX particles are quickly precipitated to form a suspension. The precipitate in the suspension is γ-HMX, which is collected by filtration.

2. The method for preparing γ-HMX stably at room temperature based on microfluidic technology according to claim 1, characterized in that: The concentration of the solvent phase is 100 g / L, the flow rate is 1 mL / min, and the flow rate of the non-solvent phase is 80 mL / min.

3. The method for preparing γ-HMX stably at room temperature based on microfluidic technology according to claim 1, characterized in that: The concentration of the solvent phase is 150 g / L, the flow rate is 5 mL / min, and the flow rate of the non-solvent phase is 100 mL / min.

4. The method for preparing γ-HMX stably at room temperature based on microfluidic technology according to claim 1, characterized in that: The concentration of the solvent phase is 200 g / L, the flow rate is 5 mL / min, and the flow rate of the non-solvent phase is 50 mL / min.

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