Preparation method of 3, 3-bis (4-azido furazan-3-oxymethyl) oxetane

Abstract

The invention discloses a preparation method of 3, 3-bis (4-azido furazan-3-oxymethyl) oxetane, which comprises the following steps: heating 3-azido-4-hydroxyfurazan and 3, 3-dibromomethyl oxetane as raw materials in a solvent in an alkaline system under the action of a phase transfer catalyst, and carrying out a one-step reaction to obtain the 3, 3-bis (4-azido furazan-3-oxymethyl) oxetane. And the catalyst is 1, 3-bis (4-azido furazan-3-oxymethyl) oxetane. The method is short in step, simple and convenient in post-treatment and capable of realizing continuous operation.

Description

Technical Field

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

[0003] 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.

[0004] Oxetane, as a saturated four-membered cyclic ether monomer with dual active sites, can simultaneously carry two energetic groups to form a polymer skeleton. It is an important branch of energetic polymers and has broad application prospects. Furazan compounds are different from traditional energetic compounds. On the one hand, their molecular structures contain a large number of CN, C=N and N=N bonds, so they have 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 its density higher. On the other hand, due to the high electronegativity of nitrogen and oxygen atoms in furazan compounds, its nitrogen heteroaromatic ring system 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 high energy density and high standard formation enthalpy (ΔH f ), high nitrogen content and excellent heat resistance. The oxetane polymer with excellent mechanical properties and the stable furazan-based energetic groups are very suitable for the application requirements of modular energetic materials.

[0005] Modular energetic materials are an energetic compound with nitrogen heterocycle and oxetane structure obtained through computer-aided innovative molecular structure design. It has good detonation performance and insensitivity characteristics, and has the functions of liquid phase carrier of molten-cast explosive, monomer plasticizer, and single 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 according to battlefield needs through different processing and treatment to obtain various weapons and ammunition that meet the requirements. It has broad research prospects, and its application research is urgent. For example, "Furazanyl Ethers of Pentaerythritol Derivatives" Int Annu Conf ICT 28 th, 1997, 127: 176356. A method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane is disclosed. The energetic monomer contains a furazan group and an oxetane group, has a high energy density, and has application prospects as a precursor of multifunctional modular energetic materials. However, its preparation route requires separation of a disubstituted product from four products, followed by cyclization. The reaction conditions and yields are not clearly reported, the steps are cumbersome, the operation is relatively complicated, and it is difficult to apply in practice. It is urgent to find a green, simple, and high-yield reaction condition. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane, so as to solve the problems of cumbersome preparation steps, complicated operation and difficulty in practical application of modular energetic materials in the prior art.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0008] A method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane comprises the following steps:

[0009] 3-azido-4-hydroxyfurazan, 3,3-dibromomethyloxetane, a basic donor and a phase transfer catalyst are added to a polar aprotic solvent, stirred and reacted at 60-100° C. for 0.5-4 h, and then extracted, washed with water, dried, filtered, evaporated the solvent and recrystallized to obtain the final product 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane.

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

[0011] Specifically, the alkaline donor is anhydrous potassium carbonate, cesium carbonate or ferric hydroxide.

[0012] Specifically, the phase transfer catalyst is tetrabutylammonium bromide, benzyltriethylammonium chloride, methyltrialkylammonium chloride or 18-crown ether-6.

[0013] Specifically, the polar aprotic solvent is DMF, MeCN, Acetone or DMSO.

[0014] Specifically, the molar ratio of the 3-azido-4-hydroxyfuroxan, 3,3-dibromomethyloxetane, alkaline donor and phase transfer catalyst is: (2-3.5):1:(2-3.5):0.02.

[0015] Compared with the prior art, the present invention has the following technical effects:

[0016] 1. The present invention uses 3-azido-4-hydroxyfurazan and commercially available 3,3-dibromomethyloxetane as raw materials, and heats them in a solvent under a cheap and environmentally friendly potassium carbonate alkaline system to obtain 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane. Compared with the method in the literature using pentaerythritol, an explosive and dangerous substance, as raw material and 3-azido-4-hydroxyfurazan as raw material, in the presence of corrosive strong base DBU and corrosive acid trifluoromethanesulfonic acid to obtain 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane, the present invention has the advantages of easy availability of reaction raw materials and little pollution to the environment.

[0017] 2. The present invention directly uses two raw materials to carry out substitution reaction in one pot under alkaline conditions and with the action of a phase transfer catalyst, and 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane can be obtained through a one-step reaction. Compared with the method of using pentaerythritol as a raw material to obtain 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane through substitution, separation, and cyclization, the present invention has the advantages of simple reaction steps and continuous operation.

[0018] 3. The 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane obtained by the synthesis method of the present invention can be completely converted into a disubstituted product through a one-step reaction by controlling the reaction conditions. The purity is high and the reaction time is short. Only a simple separation treatment of the product is required to directly obtain a 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane product with a purity of not less than 98%. Compared with the literature method, the four nitrated furazan-substituted pentaerythritols obtained need to go through a complex separation process, and the di- and tri-substituted pentaerythritols are screened out to continue the cyclization reaction to obtain the 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane product. The reaction route is more efficient and convenient, and the post-processing is also easier, which is convenient for industrial continuous production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the H NMR spectrum of 13,3-bis(4-azidofurazan-3-oxymethyl)oxetane;

[0020] Figure 2 It is the carbon NMR spectrum of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane;

[0021] Figure 3 It is the FTIR spectrum of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane;

[0022] Figure 4 This is a high-resolution mass spectrum of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane;

[0023] Figure 5This is the DSC chart of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane. DETAILED DESCRIPTION

[0024] The synthetic route of the present invention uses 3-azido-4-hydroxyfurazan and 3,3-dibromomethyloxetane as raw materials, heats them in a solvent under the action of an alkaline system and a phase transfer catalyst, and obtains 3,3-di(4-azidofurazan-3-oxymethyl)oxetane through a one-step reaction; the synthetic route is:

[0025]

[0026] The following steps are involved:

[0027] 3-azido-4-hydroxyfurazan, 3,3-dibromomethyloxetane, a basic donor and a phase transfer catalyst are added to a polar aprotic solvent, stirred and reacted at 60-100° C. for 0.5-4 hours, and then extracted, washed with water, dried, filtered, evaporated the solvent and recrystallized to obtain the final product 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane;

[0028] Alkaline donors include anhydrous potassium carbonate, cesium carbonate and ferric hydroxide.

[0029] Phase transfer catalysts include tetrabutylammonium bromide, benzyltriethylammonium chloride, methyltrialkylammonium chloride and 18-crown-6.

[0030] Polar aprotic solvents include DMF, MeCN, Acetone, and DMSO.

[0031] The molar ratio of 3-azido-4-hydroxyfuroxan, 3,3-dibromomethyloxetane, alkaline donor and phase transfer catalyst is: (2-3.5):1:(2-3.5):0.02.

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

[0033] Embodiment 1:

[0034] This embodiment provides a method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane, comprising the following steps:

[0035] 3-azido-4-hydroxyfuroxan (2.55 g, 0.02 mol), 3,3-dibromomethyloxetane (2.44 g, 0.01 mol), anhydrous potassium carbonate (2.76 g, 0.02 mol), and phase transfer catalyst 18-crown ether-6 (0.05 g, 0.0002 mol) were added to dimethylformamide DMF (30 ml) at room temperature, stirred sufficiently, and reacted at 75°C for 1.5 h. After the reaction was completed, water and dichloromethane were added for extraction, and then washed with water, dried over anhydrous magnesium sulfate, filtered, the solvent was evaporated, and recrystallized to finally obtain the target product as white crystals (2.72 g, yield 81%).

[0036] Structure identification:

[0037] (1) C NMR spectroscopy analysis

[0038] The obtained spectrum is as follows Figure 2 As shown in the figure, it can be seen that 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane shows similar peaks of azidofurazan characteristics at 159.26ppm and 145.23ppm, indicating the introduction of azidofurazan; the characteristic peaks of methyloxetane at 73.42ppm, 73.33ppm, and 42.68ppm do not change much, indicating that the main body of methyloxetane has not changed. The corresponding hydrogen spectrum is as follows Figure 1 As shown, the area obtained by integrating the corresponding peaks is 1:1, which also confirms the successful synthesis of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane.

[0039] (2) Infrared spectrum analysis

[0040] The obtained spectrum was compared with that of the similar product 3,3-bis(4-nitrofurazan-3-oxymethyl)oxetane. Figure 3 As shown, it can be seen that the characteristic peak of oxetane at 835 cm-1 still exists, indicating that the oxetane structure still exists in the pure monomer; the appearance of the characteristic absorption peaks of the azido group at 2100 cm-1 and 2150 cm-1 indicates the successful synthesis of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane.

[0041] (3) High-resolution mass spectrometry

[0042] The obtained pale yellow crystals were subjected to high resolution mass spectrometry analysis. Figure 4 As shown, the highest peak in the obtained spectrum (337.08619) is consistent with the predicted molecular weight of the hydrogenated structure (337.0757), indicating the successful synthesis of 3,3-bis(4-nitrofurazan-3-oxymethyl)oxetane.

[0043] As shown in Table 1, the single crystal X-ray diffraction results of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane show that its structure is consistent with expectations and has a high density, indicating the successful synthesis of 3,3-bis(4-nitrofurazan-3-oxymethyl)oxetane.

[0044] Figure 5 The DSC graph of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane shows that it has a low melting point (79°C) and a high thermal decomposition peak temperature (186°C), which can support its use as a multifunctional modular energetic material in multiple fields.

[0045] Table 1 Single crystal X-ray diffraction results of 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane

[0046]

[0047]

[0048] Embodiment 2:

[0049] This example provides a method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane. The preparation method and steps of this example are the same as those of Example 1, except that the addition amount of 3-azido-4-hydroxyfurazan is 4.47 g, 0.035 mol, and the reaction is carried out at 75° C. for 3.5 h. The final product is 2.88, with a yield of 49%.

[0050] The structural identification results of this example are the same as those of Example 1.

[0051] Embodiment 3:

[0052] This example provides a method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane. The preparation method and steps of this example are the same as those of Example 1, except that the amount of anhydrous potassium carbonate added is 4.83 g, 0.035 mol, and the reaction is carried out at 75° C. for 3.5 h. The final product is 2.52 g, with a yield of 77.5%.

[0053] The structural identification results of this example are the same as those of Example 1.

[0054] Embodiment 4:

[0055] This example provides a method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane. The preparation method and steps of this example are the same as those of Example 1, except that the amount of 3-azido-4-hydroxyfurazan added is 4.47 g, 0.035 mol, the polar aprotic solvent used is 50 mL of DMF, the reaction time is 3.5 h, and the final product is 2.74 g, with a yield of 46.6%.

[0056] The structural identification results of this example are the same as those of Example 1.

[0057] Embodiment 5:

[0058] This example provides a method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane. The preparation method and steps of this example are the same as those of Example 1, except that the polar aprotic solvent used is 30 mL of MeCN, the reaction time is 3.5 h, and the final product is 2.38 g with a yield of 70.9%.

[0059] The structural identification results of this example are the same as those of Example 1.

[0060] Embodiment 6:

[0061] This example provides a method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane. The preparation method and steps of this example are the same as those of Example 1, except that the polar aprotic solvent used is 30 mL of DMSO, the reaction time is 3.5 h, and the final product is 2.44 g with a yield of 72.5%.

[0062] The structural identification results of this example are the same as those of Example 1.

[0063] Embodiment 7:

[0064] This example provides a method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane. The preparation method and steps of this example are the same as those of Example 1, except that the polar aprotic solvent used is 30 mL of Acetone, the reaction is carried out at 60° C. for 3.5 h, and the final product is 1.84 g with a yield of 54.8%.

[0065] The structural identification results of this example are the same as those of Example 1.

Claims

1. A method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane, characterized in that: The following steps are involved: 3-azido-4-hydroxyfurazan, 3,3-dibromomethyloxetane, a basic donor and a phase transfer catalyst are added to a polar aprotic solvent, stirred and reacted at 60-100° C. for 0.5-4 h, and then extracted, washed with water, dried, filtered, evaporated the solvent and recrystallized to obtain the final product 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane.

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

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

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

5. The method for preparing 3,3-bis(4-azidofurazan-3-oxymethyl)oxetane according to claim 1, characterized in that: The molar ratio of the 3-azido-4-hydroxyfuroxan, 3,3-dibromomethyloxetane, alkaline donor and phase transfer catalyst is: (2-3.5):1:(2-3.5):0.02.

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