Preparation method of 3-(4-nitrofurazan-3-oxymethyl)-3-azido methyl oxetane

Abstract

The invention discloses a preparation method of 3-(4-nitrofurazan-3-oxymethyl)-3-azido methyl oxetane, which comprises the following steps: reacting 3, 3-dibromomethyl oxetane with sodium azide under a mild condition to obtain an intermediate 3-bromomethyl-3-azido methyl oxetane; and then heating with 3-nitro-4-hydroxyfurazan in a cheap and environment-friendly inorganic alkaline solvent system in the presence of a catalytic amount of a phase transfer catalyst to obtain a target product. The product disclosed by the invention has good detonation performance and insensitive characteristic, also has the functions of a melt-cast explosive liquid-phase carrier, a monomer plasticizer and a single-compound explosive, can be polymerized to be used as a structural energetic material or an energetic adhesive, and has a considerable application prospect.

Description

Technical Field

[0001] The invention belongs to the field of insensitive energetic materials and relates to a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. Background Art

[0002] Modular energetic materials refer to energetic materials that can be mass-produced and manufactured in series based on standardization. They can be combined with other units through different forms of processing to form products with relatively independent functions, and can be decomposed, combined, and interchangeable. They can be given a wide range of applications through reasonable structural design to meet the needs of different weapons and equipment, and can be mass-produced and scaled through standardized production. This is one of the main development directions in the field of energetic materials in the future. Research on modular energetic material design, customization, and synthesis has recently received attention.

[0003] As a saturated four-membered cyclic ether monomer with dual active sites, oxetane can simultaneously load two energetic groups to form a polymer skeleton. It is an important branch of energetic polymers and has broad application prospects. Furoxan compounds are different from traditional energetic compounds. On the one hand, they contain a large number of CN, C=N and N=N bonds in their molecular structure, so they have a very high formation enthalpy. In addition, the aromaticity of the furazan ring enhances the thermal stability of furazan derivatives, and the coplanarity of the furazan ring makes it have a higher density; on the other hand, due to the high electronegativity of nitrogen and oxygen atoms, the nitrogen heteroaromatic ring system of furazan compounds can form a large π bond of a benzene-like structure, which has the properties of insensitivity and thermal stability. Therefore, many of the furazan energetic derivatives have the advantages of high energy density, high standard formation enthalpy (ΔHf), high nitrogen content and excellent heat resistance. Oxetane polymers with excellent mechanical properties and stable furazan-based energetic groups are very suitable for the application requirements of modular energetic materials.

[0004] Compared with the insufficient production capacity faced by traditional high-precision ammunition, modular energetic materials have obtained an energetic compound with nitrogen heterocycle and oxetane structure through computer-aided innovative molecular structure design. While having good detonation performance and insensitivity characteristics, it also has the functions of liquid phase carrier of molten-cast explosives, monomer plasticizer, and single-element explosive. It can also be polymerized as a new type of multifunctional insensitive energetic material used as structural energetic material or energetic adhesive. As a new concept of energetic materials, modular multifunctional energetic materials can be mass-produced in peacetime, and then differentiated by different processing according to battlefield needs to obtain various weapons and ammunition that meet the requirements. It has broad research prospects, and it is urgent to carry out applied research on it. For example, "Furazanyl Ethers of Pentaerythritol Derivatives" IntAnnu Conf ICT 28th, 1997, 127: 176356. discloses a method for preparing 3,3-bis(4-nitrofurazan-3-oxymethyl)oxetane, wherein the energetic monomer contains a furazan group and an oxetane base, has a high energy density, and has an application prospect as a multifunctional modular energetic material, but the oxetane ring carries two large side groups and is symmetrically distributed, resulting in a sudden increase in the crystallization trend of the monomer, which also seriously affects the subsequent polymerization process of the monomer, resulting in the inability to obtain a high polymer that can meet the application standard, and is difficult to be applied in practice. For this reason, designing an energetic furazan-substituted oxetane compound that can retain the high-energy insensitivity characteristics of 3,3-bis(4-nitrofurazan-3-oxymethyl)oxetane and overcome the performance defects caused by the highly symmetrical structure has considerable application prospects. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane, which can retain the high-energy insensitive characteristics while overcoming the performance defects caused by the highly symmetrical structure.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0007] A method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane comprises the following steps:

[0008] Step 1, adding an azidating agent and 3,3-dibromomethyloxetane to a polar aprotic solvent, stirring and reacting at 45-85° C. for 0.5-2 h, then extracting, washing, drying, filtering, and evaporating the solvent to obtain an intermediate 3-azidomethyl-3-bromomethyloxetane;

[0009] Step 2: The intermediate 3-azidomethyl-3-bromomethyloxetane obtained in step 1, 3-nitro-4-hydroxyfuroxan and an alkaline donor are added to a polar aprotic solvent, stirred and reacted at 45 to 85° C. for 0.5 to 2 h, and then extracted, washed with water, dried, filtered and the solvent evaporated to obtain 3-(4-nitrofuroxan-3-oxymethyl)-3-azidomethyloxetane.

[0010] The present invention also includes the following technical features:

[0011] Specifically, the azidation reagent is sodium azide, trimethylsilyl azido, p-toluenesulfonyl azide, ethyl azidoacetate, tetrabutylammonium azide or tri-n-butyltin azide.

[0012] Specifically, the molar ratio of the 3,3-dibromomethyloxetane to the azidation reagent is 1:(0.8-1.2).

[0013] Specifically, the alkaline donor is anhydrous potassium carbonate, cesium carbonate or ferric hydroxide.

[0014] Specifically, the phase transfer catalyst is tetrabutylammonium bromide, benzyltriethylammonium chloride, methyltrialkylammonium chloride or 18-crown ether-6.

[0015] Specifically, the molar ratio of the intermediate 3-azidomethyl-3-bromomethyloxetane, 3-nitro-4-hydroxyfurazan, alkaline donor and phase transfer catalyst is 1:(1-2):(1-2):0.02.

[0016] Specifically, the polar aprotic solvent is DMF, MeCN, Acetone or DMSO.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] 1. The present invention uses commercially available 3,3-dibromomethyloxetane as a raw material, performs an azidation reaction under mild conditions to obtain a reaction intermediate 3-bromomethyl-3-azidomethyloxetane, and then heats it with easily available 3-nitro-4-hydroxyfurazan in a cheap and environmentally friendly potassium carbonate alkaline system to obtain 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. The method has the advantages of easy availability of reaction raw materials, mild reaction conditions, safety and environmental protection, and simple reaction steps, which can be operated continuously and is convenient for industrial continuous production.

[0019] 2. The 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane obtained by the synthesis method of the present invention is a novel multifunctional insensitive energetic material which has good detonation performance and insensitivity characteristics, and functions as a liquid phase carrier of melt-cast explosives, a monomer plasticizer, and a single explosive, and can also be polymerized as a structural energetic material or an energetic adhesive. The product exists in a liquid state at room temperature, and subsequent polymerization tests show that the polymer has excellent mechanical properties.

[0020] 3. The 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane obtained by the synthesis method of the present invention introduces multiple energetic groups into the same energetic monomer through molecular structure design, which can significantly improve its compatibility and make it more conducive to practical application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of 13-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane;

[0022] Figure 2 is the carbon NMR spectrum of 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane;

[0023] Figure 3 is the FTIR spectrum of 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane;

[0024] Figure 4 It is a high-resolution mass spectrum of 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane;

[0025] Figure 5 This is the DSC chart of 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. DETAILED DESCRIPTION

[0026] The present invention uses commercially available 3,3-dibromomethyloxetane and a certain amount of sodium azide to react under mild conditions to obtain an intermediate 3-bromomethyl-3-azidomethyloxetane, and then heats it with easily available 3-nitro-4-hydroxyfurazan in a cheap and environmentally friendly inorganic alkaline solvent system in the presence of a catalytic amount of a phase transfer catalyst to obtain the target product. The synthetic route is as follows:

[0027]

[0028] The method comprises the following steps:

[0029] Step 1, adding an azidating agent and 3,3-dibromomethyloxetane to a polar aprotic solvent, stirring and reacting at 45-85° C. for 0.5-2 h, then extracting, washing, drying, filtering, and evaporating the solvent to obtain an intermediate 3-azidomethyl-3-bromomethyloxetane;

[0030] Step 2: Add the intermediate 3-azidomethyl-3-bromomethyloxetane obtained in step 1, 3-nitro-4-hydroxyfuroxan, a basic donor and a phase transfer catalyst to a polar aprotic solvent, stir and react at 45 to 85° C. for 0.5 to 2 h, then extract, wash with water, dry, filter and evaporate the solvent to obtain 3-(4-nitrofuroxan-3-oxymethyl)-3-azidomethyloxetane.

[0031] In step 1, the azidation reagent includes sodium azide, trimethylsilyl azido, p-toluenesulfonyl azide, ethyl azidoacetate, tetrabutylammonium azide, and tri-n-butyltin azide.

[0032] In step 1, the molar ratio of 3,3-dibromomethyloxetane to the azidation reagent is 1:(0.8-1.2).

[0033] Step 2: Alkaline donors include anhydrous potassium carbonate, cesium carbonate and ferric hydroxide.

[0034] The phase transfer catalyst in step 2 includes tetrabutylammonium bromide, benzyltriethylammonium chloride, methyltrialkylammonium chloride and 18-crown ether-6.

[0035] The molar ratio of the intermediate 3-azidomethyl-3-bromomethyloxetane, 3-nitro-4-hydroxyfurazan, alkaline donor and phase transfer catalyst in step 2 is 1:(1-2):(1-2):0.02.

[0036] Polar aprotic solvents include DMF, MeCN, Acetone, and DMSO.

[0037] 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.

[0038] Embodiment 1:

[0039] This embodiment provides a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane, comprising the following steps:

[0040] Step 1. Add 3,3-dibromomethyloxetane (2.44 g, 0.01 mol) and sodium azide (0.65 g, 0.01 mol) to 3 ml of DMF at room temperature, stir well, and react at 60°C for 1.5 h. After the reaction, add water and ethyl acetate for extraction, wash with water, dry over anhydrous magnesium sulfate, filter and evaporate to finally obtain a yellow oily 3-azidomethyl-3-bromomethyloxetane (1.98 g, yield 96%) as an intermediate.

[0041] Step 2: Add the intermediate (2.06 g, 0.01 mol) obtained in step 1, 3-nitro-4-hydroxyfuroxan (2.62 g, 0.02 mol), anhydrous potassium carbonate (2.76 g, 0.02 mol), and phase transfer catalyst 18-crown ether-6 (0.05 g, 0.0002 mol) into dimethylformamide (DMF) (30 ml) at room temperature, stir well, and react at 75°C for 1.5 h. After the reaction, add water and dichloromethane for extraction, then wash with water, dry over anhydrous magnesium sulfate, filter, and evaporate the solvent to obtain the final yellow oily target product (2.14 g, yield 83.5%).

[0042] Structure identification:

[0043] (1) C NMR spectroscopy analysis

[0044] The obtained oily product was analyzed by carbon NMR spectroscopy. Figure 2 As shown in the figure, the characteristic peaks of nitrofurazan at 158.79ppm and 152.79ppm did not shift, and the peak shape still maintained the high-low peak shape of nitrofurazan, indicating that the nitro group of furazan still existed; the characteristic peaks of methyloxetane at 74.94ppm, 74.15ppm, and 43.37ppm did not change much, shifting to 74.28ppm, 74.14ppm, and 42.76ppm, respectively, indicating that the main body of methyloxetane did not change. Correspondingly, the carbon spectrum peak of bromomethyl at 36.44ppm shifted to 52.65ppm downfield, indicating that bromomethyl was converted into azidomethyl with stronger electronegativity (weaker shielding effect). The hydrogen spectrum is shown in the figure. Figure 1 As shown, the area obtained by integrating the corresponding peaks is 1:2:1, which also confirms the successful synthesis of 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane.

[0045] (2) Infrared spectrum analysis

[0046] The obtained spectrum is as follows Figure 3As shown, it can be seen that the characteristic peak of 3,3-dibromomethyloxetane at 835cm-1 still exists, indicating that the oxetane structure still exists in the pure monomer; the nitro infrared absorption peak at 1624cm-1 also still exists, indicating that the product still contains nitro; and the appearance of the azido characteristic absorption peaks at 2100cm-1 and 2150cm-1 indicates the successful synthesis of 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane.

[0047] (3) High-resolution mass spectrometry

[0048] The obtained pale yellow crystals were subjected to high resolution mass spectrometry analysis. Figure 4 As shown, the highest peak in the obtained spectrum (257.06735) is completely consistent with the predicted molecular weight of the hydrogenated structure (257.0634), indicating the successful synthesis of 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane.

[0049] like Figure 5 As shown in Table 1, the key parameters of energetic materials such as density, detonation performance, stability, and oxygen balance of the present invention are significantly improved, while the performance defects caused by the highly symmetrical structure can be overcome, and the present invention has considerable application prospects.

[0050] Table 1 Comparison of density, detonation velocity and sensitivity of 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane and BAMO

[0051]

[0052] Embodiment 2:

[0053] The present embodiment provides a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. The preparation method and steps of the present embodiment are the same as those of Example 1, except that: in step 1, the amount of sodium azide added (0.78 g, 0.012 mol) is 0.78 g, 0.012 mol, and a yellow oily 3-azidomethyl-3-bromomethyloxetane (2.00 g, yield 97%) is obtained as an intermediate; in step 2, the amount of 3-nitro-4-hydroxyfurazan added is 1.31 g, 0.01 mol, and the amount of anhydrous potassium carbonate added is 1.88 g, 0.01 mol, and the reaction time is 1.2 h. Finally, the final oily product 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane obtained in step 2 is 2.2 g, and the yield is 85.8%.

[0054] The structural identification results of this example are the same as those of Example 1.

[0055] Embodiment 3:

[0056] The present embodiment provides a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. The preparation method and steps of the present embodiment are the same as those of Example 1, except that: in step 1, the amount of sodium azide added (0.52 g, 0.008 mol) and the reaction time are 1 h to obtain a yellow oily 3-azidomethyl-3-bromomethyloxetane (1.69 g, yield 82%) as an intermediate; in step 2, the amount of 3-nitro-4-hydroxyfurazan added is 1.31 g, 0.01 mol, and the amount of anhydrous potassium carbonate added is 3.96 g, 0.02 mol, and the reaction time is 1.2 h. Finally, the final oily product 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane obtained in step 2 is 2.22 g, with a yield of 86.5%.

[0057] The structural identification results of this example are the same as those of Example 1.

[0058] Embodiment 4:

[0059] The present embodiment provides a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. The preparation method and steps of the present embodiment are the same as those of Example 1, except that: in step 1, the reaction temperature is 80° C., the reaction time is 0.5 h, and a yellow oily 3-azidomethyl-3-bromomethyloxetane (1.70 g, yield 82.4%) is obtained as an intermediate; in step 2, the amount of 3-nitro-4-hydroxyfurazan added is 1.31 g, 0.01 mol, the reaction temperature is 60° C., the reaction time is 2 h, and the final oily product 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane obtained in step 2 is 1.88 g, with a yield of 73.5%.

[0060] The structural identification results of this example are the same as those of Example 1.

[0061] Embodiment 5:

[0062] The present embodiment provides a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. The preparation method and steps of the present embodiment are the same as those of Example 1, except that: in step 2, 3-nitro-4-hydroxyfurazan is added in an amount of 1.31 g, 0.01 mol, and anhydrous potassium carbonate is added in an amount of 1.88 g, 0.01 mol. The solvent used is 10 mL of DMSO. Finally, the final oily product 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane obtained in step 2 is 1.97 g, with a yield of 76.5%.

[0063] The structural identification results of this example are the same as those of Example 1.

[0064] Embodiment 6:

[0065] The present embodiment provides a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. The preparation method and steps of the present embodiment are the same as those of Example 1, except that: in step 1, the reaction temperature is 45° C., the reaction time is 2 h, and a yellow oily 3-azidomethyl-3-bromomethyloxetane (1.42 g, yield 70.1%) is obtained as an intermediate; in step 2, 3-nitro-4-hydroxyfurazan is added in an amount of 1.31 g, 0.01 mol, and anhydrous potassium carbonate is added in an amount of 1.88 g, 0.01 mol, and the reaction temperature is 45° C., and the final oily product 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane obtained in step 2 is 1.74 g, with a yield of 67.8%.

[0066] The structural identification results of this example are the same as those of Example 1.

[0067] Embodiment 7:

[0068] The present embodiment provides a method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane. The preparation method and steps of the present embodiment are the same as those of Example 1, except that: in step 2, the amount of 3-nitro-4-hydroxyfurazan added is 1.31 g, 0.01 mol, the amount of anhydrous potassium carbonate added is 1.88 g, 0.01 mol, and the selected phase transfer catalyst is tetrabutylammonium bromide (TBAB) (0.07 g, 0.0002 mol). Finally, the final oily product 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane obtained in step 2 is 1.88 g, with a yield of 73.4%.

[0069] The structural identification results of this example are the same as those of Example 1.

Claims

1. A method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane, characterized in that: The following steps are involved: Step 1, adding an azidating agent and 3,3-dibromomethyloxetane to a polar aprotic solvent, stirring and reacting at 45-85° C. for 0.5-2 h, then extracting, washing, drying, filtering, and evaporating the solvent to obtain an intermediate 3-azidomethyl-3-bromomethyloxetane; Step 2: The intermediate 3-azidomethyl-3-bromomethyloxetane obtained in step 1, 3-nitro-4-hydroxyfuroxan and an alkaline donor are added to a polar aprotic solvent, stirred and reacted at 45 to 85° C. for 0.5 to 2 h, and then extracted, washed with water, dried, filtered and the solvent evaporated to obtain 3-(4-nitrofuroxan-3-oxymethyl)-3-azidomethyloxetane.

2. The method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane according to claim 1, characterized in that: The azidation reagent is sodium azide, trimethylsilyl azido, p-toluenesulfonyl azide, ethyl azidoacetate, tetrabutylammonium azide or tri-n-butyltin azide.

3. The method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane according to claim 1, characterized in that: The molar ratio of the 3,3-dibromomethyloxetane to the azidation reagent is 1:(0.8-1.2).

4. The method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane according to claim 1, characterized in that: The alkaline donor is anhydrous potassium carbonate, cesium carbonate or ferric hydroxide.

5. The method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane according to claim 1, characterized in that: The phase transfer catalyst is tetrabutylammonium bromide, benzyltriethylammonium chloride, methyltrialkylammonium chloride or 18-crown ether-6.

6. The method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane according to claim 1, characterized in that: The molar ratio of the intermediate 3-azidomethyl-3-bromomethyloxetane, 3-nitro-4-hydroxyfuroxan, alkaline donor and phase transfer catalyst is 1:(1-2):(1-2):0.

02.

7. The method for preparing 3-(4-nitrofurazan-3-oxymethyl)-3-azidomethyloxetane according to claim 1, characterized in that: The polar aprotic solvent is DMF, MeCN, Acetone or DMSO.

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