Aliphatic energetic plasticizer and preparation method thereof

Abstract

The present invention discloses an aliphatic energetic plasticizer and a preparation method thereof. By introducing an energetic azide group and a reduced-sensitivity ester group into an aliphatic compound containing a nitro group, a novel aliphatic energetic plasticizer having the advantages of low viscosity, low glass transition temperature, low sensitivity, good safety performance, etc. is obtained, which has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of energetic plasticizers, in particular to an aliphatic energetic plasticizer and a preparation method thereof. Background Art

[0002] Plasticizers added to explosives and propellants can improve the physical properties of the binder or energetic material itself, while also serving as auxiliary fuels to enhance the specific impulse of the propellant. The earliest plasticizers used in explosives systems were inert plasticizers. These inert plasticizers focused on their most basic functions: improving mechanical properties and reducing processing difficulties. Later developments introduced energetic groups such as nitro, azide, and fluorodinitro groups into their molecules, resulting in energetic plasticizers. Compared to inert plasticizers, energetic plasticizers not only increase the total energy content of the weapon system but also improve the oxygen balance of the explosive and propellant. Subsequently, energetic plasticizers have gradually diversified, resulting in the synthesis of a large number of highly effective energetic plasticizers. An ideal energetic plasticizer should possess both excellent physical and chemical properties, requiring it to possess energetic content, stability, and low sensitivity while meeting requirements such as glass transition temperature, low viscosity, good compatibility with binders, and low mobility.

[0003] Compared to aromatic compounds, energetic plasticizers based on aliphatic compounds have relatively low molecular weights, are more likely to exist as liquids, and exhibit superior glass transition temperatures and viscosity properties. The introduction of energetic azide groups not only imparts these plasticizers with favorable energy properties but also enhances various physicochemical properties, including stability, solvent resistance, and antioxidant properties. Ester groups, as flexible groups, can significantly reduce the sensitivity of energetic molecules, improving their safety. Summary of the Invention

[0004] The purpose of the present invention is to provide an aliphatic energetic plasticizer and a preparation method thereof in order to solve the above-mentioned problems. The present invention introduces an energetic azide group and a desensitized ester group into an aliphatic compound containing a nitro group to obtain a new aliphatic energetic plasticizer. The synthesis method of this type of plasticizer is simple, and it has the advantages of low viscosity, low glass transition temperature, good safety performance, etc., and is a potential application-type energetic plasticizer.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] An aliphatic energetic plasticizer, the structural formula of which is as follows:

[0007]

[0008] The present invention also provides a method for preparing an aliphatic energetic plasticizer, which uses 1,3-dichloro-2-propanol of formula I and nitropropionic acid of formula III as starting materials, and undergoes two steps of azidation and esterification to obtain the energetic plasticizer.

[0009] The synthesis method is carried out according to the following reaction formula:

[0010]

[0011] A further solution comprises the following steps:

[0012] Step 1, reacting the compound of formula I with sodium azide in dimethyl sulfoxide to obtain the compound of formula II: 1,3-diazide-2-propanol;

[0013]

[0014] I was dissolved in dimethyl sulfoxide at room temperature, and sodium azide was gradually added under stirring. After the addition was complete, the temperature was slowly raised to 85°C and the reaction was carried out for 6-8 hours. After the reaction was completed, the reaction solution was poured into ice water. The organic phase was extracted with dichloromethane. The organic phases were combined, washed with water, and dried to dryness to obtain intermediate II.

[0015] The intermediate product of formula II and the nitropropionic acid of formula III are mixed and subjected to esterification reaction to obtain a compound of formula NDAE;

[0016]

[0017] II and nitropropionic acid were dissolved in dichloromethane at room temperature, and concentrated sulfuric acid was added with stirring. The temperature was slowly raised to 70°C and refluxed for 10-12 hours. After the reaction, the mixture was cooled to room temperature. Water was added and stirred for 15 minutes. The organic phase was collected, the aqueous phase was extracted with dichloromethane, and the organic phases were combined. The extracted organic phase was washed with sodium bicarbonate solution and purified water, and dried and spin-dried to obtain the product NDAE in a yield of approximately 60%.

[0018] A further embodiment is that in step 1, the reaction solvent comprises dimethyl sulfoxide, N,N-dimethylformamide, 1,3-dichloro-2-propanol and sodium azide in a molar ratio of 1:2 to 10;

[0019] The reaction temperature is 40°C-80°C.

[0020] A further solution is that in step 2, the intermediate product of formula II and the nitropropionic acid of formula III are mixed, the catalyst and dehydrating agent are one of concentrated sulfuric acid, p-toluenesulfonic acid, and dicyclohexylcarbodiimide, and the amount of the catalyst and dehydrating agent added is 10%-30% of the mass of the added alcohol.

[0021] In the reaction for preparing the compound of formula NDAE, the molar ratio of formula II to formula III is 1-5:1.

[0022] The beneficial effects of the present invention are:

[0023] The present invention discloses an aliphatic energetic plasticizer and a preparation method thereof. By introducing an energetic azide group and a reduced-sensitivity ester group into an aliphatic compound containing a nitro group, a novel aliphatic energetic plasticizer having the advantages of low viscosity, low glass transition temperature, good safety performance, etc. is obtained, which has broad application prospects. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] Synthesis of compound 1,3-diazide-2-propanol of formula (II)

[0027]

[0028] Dissolve 1,3-dichloro-2-propanol (1.29 g, 10 mmol) in 30 ml of dimethyl sulfoxide (DMSO). Heat to 40°C. Gradually add NaN3 (1.43 g, 22 mmol) while stirring. After addition, slowly heat to 75°C and allow to react for 8 hours. After the reaction is complete, cool to room temperature and pour the reaction solution into ice water. Extract the organic phase three times with 10 ml of dichloromethane, then combine the combined organic phases. Wash the product three times with 15 ml of pure water. Dry the washed product to obtain 1.12 g of Intermediate II with a yield of approximately 80%.

[0029] Example 2

[0030] Synthesis of the compound (NDAE) [1-nitropropionic acid-1,3-diazide propyl ester]

[0031]

[0032] II (0.71 g, 5 mmol) and nitropropionic acid (0.59 g, 5 mmol) were dissolved in dichloromethane, and 0.1 g of concentrated sulfuric acid was added under stirring. The temperature was slowly raised to 70 ° C and refluxed for 10 h. After the reaction, it was cooled to room temperature. Water was added and stirred for 15 min, and the organic phase was collected. The organic phase was extracted three times with 10 ml of dichloromethane and the organic phases were combined. The sodium bicarbonate solution and pure water were washed three times each. The organic phase was dried and spin-dried to obtain the product [1-nitropropionic acid-1,3-diazide propanol ester] NDAE 0.82 g (yield about 67%). The density of the product NDAE is 1.35 g / cm 3 The glass transition temperature is -62°C, the thermal decomposition temperature is 234°C, the impact sensitivity is >20J, and the viscosity is 24mPa·s. It has excellent performance, low viscosity, low glass transition temperature and good safety performance.

[0033] The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner unless there is any contradiction. In order to avoid unnecessary repetition, the present invention will no longer describe various possible combinations separately. In addition, the various different embodiments of the present invention can also be arbitrarily combined. As long as they do not violate the ideas of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An aliphatic energetic plasticizer having the following structural formula: 。 2. The method for preparing an aliphatic energetic plasticizer according to claim 1, wherein: Using 1,3-dichloro-2-propanol of formula I and nitropropionic acid of formula III as starting materials, an energetic plasticizer is obtained through two steps of azidation and esterification. The synthesis method is carried out according to the following reaction formula: ； Step 1, reacting the compound of formula I with sodium azide in dimethyl sulfoxide to obtain the compound of formula II: 1,3-diazide-2-propanol; ； I was dissolved in dimethyl sulfoxide at room temperature, and sodium azide was gradually added under stirring. After the addition was complete, the temperature was slowly raised to 85°C and the reaction was carried out for 6-8 hours. After the reaction was completed, the reaction solution was poured into ice water. The organic phase was extracted with dichloromethane. The organic phases were combined, washed with water, and dried to dryness to obtain intermediate II. Step 2, mixing the intermediate product of formula II and the nitropropionic acid of formula III to undergo esterification reaction to obtain a compound of formula NDAE; ； At room temperature, II and nitropropionic acid were dissolved in dichloromethane, and concentrated sulfuric acid was added with stirring; the temperature was slowly raised to 70°C and refluxed for 10-12 hours; after the reaction was completed, the mixture was cooled to room temperature; water was added and stirred for 15 minutes, the organic phase was collected, the aqueous phase was extracted with dichloromethane, and the organic phases were combined; the extracted organic phase was washed with sodium bicarbonate solution and pure water, and dried and spin-dried to obtain the product NDAE.

3. The method for preparing an aliphatic energetic plasticizer according to claim 2, wherein: In the step 1, the molar ratio of 1,3-dichloro-2-propanol to sodium azide is 1:2-10.

4. The method for preparing an aliphatic energetic plasticizer according to claim 2, wherein: In step 2, the intermediate product of formula II and the nitropropionic acid of formula III are mixed, and the amount of concentrated sulfuric acid added is 10%-30% of the mass of the alcohol added; In the reaction for preparing the compound of formula NDAE, the molar ratio of formula II to formula III is 1-5:1.

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