Preparation method and application of epoxy azidopropane

Abstract

The invention discloses a preparation method and application of epoxy azidopropane. The one-pot preparation method is adopted, halogenated epoxide and inorganic azide are reacted to prepare epoxy azidopropane, separation and purification of intermediates are not needed, and the method is simple, convenient and efficient. The preparation method is simple, the reaction condition is mild, the product purity is high, the yield is high, amplification synthesis is easy, and the prepared epoxy azidopropane and the polymer thereof can be applied as energetic materials.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and in particular to a preparation method and application of epoxyazidepropane. Background Art

[0002] With the development of high-energy solid propellants, the requirements for energy levels are constantly increasing, and an effective way to improve the energy level is to use energetic adhesives to replace existing inert adhesives. Glycidyl polyazide (GAP) is an energetic adhesive with an azide group in the side chain and a polyether structure in the main chain. It has the advantages of high energy, high density and low characteristic signal, and is considered to be the most promising type of energetic adhesive. One of the effective ways to prepare GAP using propylene oxide as a monomer is to first azidize epichlorohydrin to obtain an epoxyazide propane compound, and then ring-opening polymerization to obtain GAP (Nature communication, 2019, 10, 293.).

[0003] Currently, there are no commercial products of epoxyazidepropane compounds. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above technical background and provide a preparation method and application of epoxyazidepropane.

[0005] The invention provides a method for preparing epoxyazide propane, which is prepared by reacting a halogenated epoxide with an inorganic azide compound.

[0006] The present invention also provides an application of the epoxyazide propane and its polymer as an energetic material.

[0007] The present invention has the following beneficial effects.

[0008] The present invention provides a preparation method and application of epoxyazidopropane. The present invention adopts a one-pot preparation method, utilizes halogenated epoxides and inorganic azide compounds to react to obtain epoxyazidopropane, does not require separation and purification of intermediates, is simple and efficient. The reaction conditions are mild, the product purity is high, the yield is high, and it is easy to scale up the synthesis. The obtained epoxyazidopropane and its polymer can be used as energetic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0010] Figure 1This is the H NMR spectrum of the epoxyazide propane compound prepared in Example 1;

[0011] Figure 2 This is the NMR carbon spectrum of the epoxyazide propane compound prepared in Example 1;

[0012] Figure 3 This is the gas chromatogram of the epoxyazidepropane compound prepared in Example 1. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0014] The following is a detailed description of the preparation method and application of epoxyazidepropane provided in an embodiment of the present invention.

[0015] In a first aspect, an embodiment of the present invention provides a method for preparing epoxyazide propane, which is prepared by reacting a halogenated epoxide with an inorganic azide compound.

[0016] The embodiment of the present invention provides a method for preparing epoxyazide propane, which is prepared by reacting halogenated epoxide and inorganic azide compound as raw materials. Among them: azide compound is a class of compounds containing three nitrogen-connected structures, the energy of the azide group is very high, and the nitrogen content and energy of the compound can be significantly increased, and the epoxy group is a unique functional group, and its structure connects a carbon atom and a hydrogen atom at both ends of the oxygen atom. This structure gives the epoxy group extremely strong reactivity, allowing it to participate in a variety of chemical reactions, such as ring-opening polymerization or addition reaction with other compounds, thereby leading to the growth of the molecular chain. When a compound containing two or more epoxy groups reacts with a multifunctional compound, a cured product with a cross-linked structure is generated. In the present invention, the epoxyazide propane prepared by reacting halogenated epoxide with an inorganic azide compound contains both azide groups and epoxy groups, and as an energetic material, it can provide higher energy, so that it can be better used in propellants.

[0017] In some optional embodiments, the epoxyazide propane is prepared by a one-pot method, comprising the following steps: dissolving an inorganic azide compound in water, adding a halogenated epoxide and a weak acid, stirring once, and then adding a strong base solution, stirring a second time, to obtain the epoxyazide propane compound.

[0018] The embodiment of the present invention provides a method for preparing epoxyazidopropane, which uses halogenated epoxide and inorganic azide compound as raw materials to react to prepare epoxyazidopropane. During the reaction, the inorganic azide compound is first dissolved in water, and the halogenated epoxide and weak acid are added and stirred once. The epoxy group of the halogenated epoxide is ring-opened under the action of weak acid and the halogen in the halogenated epoxide is replaced by an azide group to generate an intermediate. Then, a strong base solution is added to realize the conversion of the intermediate from open ring to closed ring under the action of strong base, so as to obtain epoxyazidopropane compound. The preparation method of epoxyazidopropane provided above does not need to separate and purify the intermediate, and is simple and efficient. In addition, the reaction conditions are mild, the product purity is high, the yield is high, and it is easy to scale up the synthesis.

[0019] In some optional embodiments, the halogenated epoxide is one or more of epichlorohydrin, epibromohydrin, and epiiodohydrin, preferably epichlorohydrin, and the inorganic azide compound is selected from one or more of lithium azide, sodium azide, and potassium azide, preferably sodium azide.

[0020] In some optional embodiments, the weak acid is selected from one or more of acetic acid, propionic acid and butyric acid, preferably acetic acid, and the strong base is selected from one or more of sodium hydroxide and potassium hydroxide, preferably sodium hydroxide.

[0021] In some optional embodiments, the molar ratio of the inorganic azide compound to the halogenated epoxide is (1-3):1, preferably (1.1-1.5):1.

[0022] In some optional embodiments, the molar ratio of the weak acid, the strong base and the halogenated epoxide is (1-10):(2-11):1, preferably (2-4):(3-5):1.

[0023] In some optional embodiments, the first stirring time is 3-24 hours, the second stirring time is 5-15 minutes, the total reaction time is 3 to 24 hours, and the reaction temperature is room temperature.

[0024] In some optional embodiments, the method further comprises: after the reaction is completed, purifying the reaction product, wherein the purification comprises the following steps: sequentially washing the reaction product with water, extracting, combining the organic phases, drying and concentrating the reaction product to obtain an epoxyazidepropane product, wherein the extraction agent used is preferably ethyl acetate.

[0025] In some optional embodiments, the reaction equation is as follows:

[0026]

[0027] In a second aspect, an embodiment of the present invention provides an application of the above-mentioned epoxyazide propane and its polymer as an energetic material. Epoxyazide propane or the product (GAP) after polymerization of epoxyazide propane has the characteristics of high energy and high density, and can be used as an energetic material. More preferably, the product (GAP) after polymerization of epoxyazide propane can be widely used as an energetic adhesive.

[0028] The present invention will be further described below in conjunction with the embodiments.

[0029] Example 1

[0030] The method for preparing epoxyazide propane by a one-pot process comprises the following steps:

[0031] 0.860 g (13.26 mmol, 1.3 equiv) of sodium azide (NaN 3 ) was dissolved in 2.0 mL of water, and 0.80 mL (10.2 mmol, 1 equiv.) of epichlorohydrin (ECH) and 1.75 mL (30.6 mmol, 3 equiv.) of acetic acid (CH 3 COOH), stirred at room temperature for 6 hours, then added dropwise with sodium hydroxide solution (NaOH) (1.632 g NaOH, 40.8 mmol, 4 equiv. dissolved in 4.0 mL water), and continued stirring for 15 minutes, and then washed with water, extracted with ethyl acetate, the organic phases were combined, dried, and concentrated to obtain the epoxyazidopropane compound, with a reaction yield of 92.6% and a purity of 99%. The H NMR spectrum and C NMR spectrum of the epoxyazidopropane compound are shown in the attached drawings. Figure 1 and attached Figure 2 , proving that the product prepared is epoxyazide propane, gas chromatogram is attached Figure 3 , indicating that its purity is 99%.

[0032] Embodiment 2-4

[0033] Examples 2-4 investigated the effects of different reaction times on the reaction. The types of reactants, the amount of reactants fed and the reaction process were the same as those in Example 1. The results of the effects are shown in Table 1. As can be seen from Table 1, in the preparation process of epoxyazide propane, the yield can reach 81.7 by adding acetic acid for 3 hours of reaction. Combined with Example 1, it can be seen that, under the condition that other conditions remain unchanged, as the reaction time is prolonged, the yield increases. After 6 hours, the reaction time is further prolonged and the yield remains basically unchanged.

[0034] Table 1

[0035]

[0036] Embodiment 5-7

[0037] Examples 5-7 investigated the effect of the amount of sodium azide on the reaction. The types of reactants, the amounts of other reactants and the reaction process were the same as those in Example 1. The results of the effects are shown in Table 2. As can be seen from Table 2, when the molar ratio of sodium azide to epichlorohydrin was controlled to be (1.1-1.5):1, the yield of the prepared epichlorohydrin compound was above 90%, and further increasing the amount of sodium azide could not increase the yield of the product.

[0038] Table 2

[0039]

[0040] Examples 8-10

[0041] Examples 8-10 investigated the effect of the amount of acetic acid on the reaction. The types of reactants, the amounts of other reactants and the reaction process were the same as in Example 1, and the results are shown in Table 3. As can be seen from Example 9, when the sodium hydroxide equivalent is the same as the acetic acid equivalent, only acid-base neutralization reaction occurs, and a sufficient alkaline environment cannot be provided for the ring-closing reaction, so the yield of epoxyazide propane is 0.

[0042] Table 3

[0043]

[0044] As can be seen from the above, the embodiments of the present invention provide a method for preparing epoxyazide propane and its application. The present invention adopts a one-pot preparation method, and uses a halogenated epoxide and an inorganic azide compound to react to prepare epoxyazide propane, without the need to separate and purify the intermediate, which is simple and efficient. The reaction conditions are mild, the product purity is high, the yield is high, and it is easy to scale up the synthesis.

[0045] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing epoxyazide propane, characterized in that: It is prepared by reacting halogenated epoxides with inorganic azides.

2. The preparation method according to claim 1, characterized in that: The one-pot method is used to prepare the epoxyazide propane, which includes the following steps: dissolving an inorganic azide compound in water, adding a halogenated epoxide and a weak acid for a first stirring, and then adding a strong base solution for a second stirring to obtain the epoxyazide propane compound.

3. The preparation method according to claim 2, characterized in that: The halogenated epoxide is one or more of epichlorohydrin, epibromohydrin, and epiiodohydrin, preferably epichlorohydrin. The inorganic azide compound is one or more of lithium azide, sodium azide, and potassium azide, preferably sodium azide.

4. The preparation method according to claim 2, characterized in that: The weak acid is selected from one or more of acetic acid, propionic acid and butyric acid, preferably acetic acid, and the strong base is selected from one or more of sodium hydroxide and potassium hydroxide, preferably sodium hydroxide.

5. The preparation method according to claim 2, characterized in that: The molar ratio of the inorganic azide compound to the halogenated epoxide is (1-3):1, preferably (1.1-1.5):

1.

6. The preparation method according to claim 2, characterized in that: The molar ratio of the weak acid, the strong base and the halogenated epoxide is (1-10):(2-11):1, preferably (2-4):(3-5):

1.

7. The preparation method according to claim 2, characterized in that: The first stirring time is 3-24 hours, the second stirring time is 5-15 minutes, the total reaction time is 3-24 hours, and the reaction temperature is room temperature.

8. The preparation method according to claim 2, characterized in that: Also includes: After the reaction is completed, the reaction product is purified, and the purification process includes the following steps: washing the reaction product with water, extracting, combining the organic phase, drying and concentrating in sequence to obtain an epoxyazide propane product, and the extraction agent used for the extraction is preferably ethyl acetate.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The reaction equation is as follows:

10. Use of epoxyazidepropane and its polymer prepared by the preparation method according to any one of claims 1 to 9 as energetic materials.

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