A difluoroamino energetic plasticizer and its preparation method

Abstract

The present invention discloses a difluoroamino energetic plasticizer and a preparation method thereof. By introducing a difluoroamino energetic group having characteristics such as high density and high energy into the plasticizer, the energy density of the compound is increased. The preparation method of the plasticizer of the present invention is simple, the product has excellent performance, and has important practical value.

Description

Technical Field

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

[0002] Energetic plasticizers are important components of mixed explosives or propellants, increasing the burning rate and range of rockets or missiles. As modern weapons demand increasingly comprehensive material performance, the crucial role of plasticizers in increasing the energy content of explosives and propellants and regulating their mechanical properties has become increasingly prominent. An ideal plasticizer should possess both excellent physical and chemical properties, requiring it to possess energetic properties, be stable, and have low sensitivity while meeting requirements such as glass transition temperature, low viscosity, good compatibility (with binders), and low mobility. Currently, a promising approach to studying energetic plasticizers is to introduce energetic groups into compounds and polymer chains to increase energy, while simultaneously improving their mechanical properties by manipulating the compound's structure. Commonly used energetic groups include nitrate, nitro, azide, and gem-dinitro groups. The types of energetic groups have also evolved from a single functional group to two or more.

[0003] Among the many energetic groups introduced into plasticizers, difluoroamino groups, with their high density and energy, are among the most ideal groups for increasing the energy density of compounds. Furthermore, the gaseous product HF formed during the decomposition process of difluoroamino compounds not only has a low molecular weight but also a high heat of formation. Fluorine appears as an oxidant, so difluoroamino compounds act as both a combustion agent and an oxidant, improving the combustion properties of boron powder in high-energy fuels. By introducing difluoroamino groups into aliphatic ester compounds, a new type of difluoroamino energetic plasticizer can be obtained. This plasticizer is simple to prepare and produces excellent product performance, making it a potential application-oriented energetic plasticizer. Summary of the Invention

[0004] The purpose of the present invention is to provide a difluoroamino energetic plasticizer and a preparation method thereof in order to solve the above problems. The preparation method of the plasticizer of the present invention is simple and the product has excellent performance.

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

[0006] A difluoroamino energetic plasticizer having the following structural formula:

[0007] Where n=2-4.

[0008] The above-mentioned plasticizer is prepared from acetone dicarboxylic acid as a starting material through a two-step reaction of esterification and difluoroamination to obtain the above-mentioned energetic plasticizer. The preparation method is carried out according to the following reaction formula:

[0009]

[0010] A further solution specifically includes the following steps:

[0011] Step 1, reacting a compound of formula (I) with a nitroalkyl alcohol in dichloromethane to obtain a compound of formula II, 1,3-acetonedicarboxylic acid nitroalkyl ester;

[0012]

[0013] I and nitroalcohol were added to dichloromethane at room temperature, and stirred. A small amount of concentrated sulfuric acid was added. After the addition, the reaction system was heated to 60° C. and refluxed for 8-10 hours. After the reaction was completed, the temperature was lowered to room temperature, water was added to the reaction system, and stirring was continued. 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 intermediate product II.

[0014] Step 2: Mix the compound of formula II and tetramethyl difluoroaminosulfonate to undergo difluoroamination reaction to obtain a compound of formula AFE

[0015]

[0016] II and tetramethyldifluorosulfamate were added to dichloromethane, and fuming sulfuric acid was added at 0°C. After the reaction was completed, the reaction solution was poured into ice water, and the organic phase was separated. 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.

[0017] A further solution is that in step 1, the reaction solvent is dichloromethane or toluene, the molar ratio of 1,3-acetonedicarboxylic acid to nitroalcohol is 1:2-10, and the amount of concentrated sulfuric acid added is 10%-30% of the mass of the alcohol added.

[0018] A further solution is that in step 1, the reaction temperature is 60°C-100°C.

[0019] A further solution is that in step 2, the reaction is selected to be mixed with difluorosulfamate, and the cation is one of tetramethylamine, sodium, and potassium.

[0020] A further solution is that in step 2, in the reaction for preparing the compound of formula AFE, the molar ratio of the compound of formula II to the difluoroaminosulfonate is 1:2-10.

[0021] The beneficial effects of the present invention are:

[0022] The present invention discloses a difluoroamino energetic plasticizer and a preparation method thereof. By introducing a difluoroamino energetic group having characteristics such as high density and high energy into the plasticizer, the energy density of the compound is increased. The preparation method of the plasticizer of the present invention is simple, the product has excellent performance, and has important practical value. DETAILED DESCRIPTION

[0023] 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.

[0024] Example 1

[0025] Synthesis of the compound of formula (AFE2) [dinitroethyl 2,2'-bis(difluoroamino)-1,3-acetonedicarboxylate];

[0026]

[0027] 1,3-Propanedicarboxylic acid (1.46 g, 10 mmol) and nitroethanol (2.00 g, 22 mmol) were dissolved in 35 ml of dichloromethane. 0.2 g of concentrated sulfuric acid was added at room temperature, and the temperature was raised to 60°C for 8 hours. After the reaction, the mixture was cooled to room temperature, 15 ml of water was added, and stirred for 0.5 hours. The organic phase was separated, 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, then dried and spin-dried to obtain 2.32 g of 1,3-propanedicarboxylic acid nitroethyl ester (II) (yield 75%). Subsequently, 1.46 g of II (5 mmol) and 3.1 g of tetramethyldifluorosulfamate (15 mmol) were added to dichloromethane, and fuming sulfuric acid was added at 0°C for 1 hour. After the reaction was completed, the reaction solution was poured into ice water, the organic phase was separated, 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, dried and then spin-dried to obtain 1.13 g of the product 2,2-difluoroamino-1,3-acetone dicarboxylic nitroester (AFE2), with a yield of about 60%. AFE2 precursor 1,3-acetone dicarboxylic nitroethyl ester (II) Density is 1.34g / cm 3 The detonation velocity is 5425 m / s. After difluoroamination, the density of the product AFE2 is 1.43 g / cm 3 The detonation velocity is 5744m / s. Compared with the compounds without -NF2 groups, the density energy of AFE2 is significantly improved.

[0028] Example 2

[0029] Synthesis of the compound of formula (AFE2) [2,2'-bis(difluoroamino)-1,3-acetonedicarboxylic acid dinitropropyl ester]

[0030]

[0031] 1,3-Propanedicarboxylic acid (1.46 g, 10 mmol) and nitropropanol (2.31 g, 22 mmol) were dissolved in 40 ml of dichloromethane. 0.3 g of concentrated sulfuric acid was added at room temperature, and the temperature was raised to 60°C for 10 h. After the reaction, the mixture was cooled to room temperature, 20 ml of water was added, and the mixture was stirred for 0.5 h. The organic phase was separated, 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, then dried and spin-dried to obtain 1.9 g of 1,3-propanedicarboxylic acid nitropropyl ester (II) (yield approximately 60%). Subsequently, 1.6 g of II (5 mmol) and 3.1 g of tetramethyldifluorosulfamate (15 mmol) were added to dichloromethane, and fuming sulfuric acid was added at 0°C for 0.5 h. After completion, the reaction solution was poured into ice water, the organic phase was separated, 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, dried and then spin-dried to obtain 1.41 g of the product 2,2-difluoroamino-1,3-nitropropanone dicarboxylate (AFE3), with a yield of about 70%. AFE3 precursor 1,3-nitropropanone dicarboxylate (II) Density is 1.29g / cm 3 The detonation velocity is 5378 m / s. After difluoroamination, the density of the product AFE3 is 1.37 g / cm 3 The detonation velocity is 5625m / s. Compared with the compounds without -NF2 groups, the density energy of AFE3 is significantly improved.

[0032] 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. A difluoroamino energetic plasticizer having the following structural formula: Where n=2-4.

2. The method for preparing a difluoroamino energetic plasticizer according to claim 1, wherein: 1,3-acetone dicarboxylic acid and nitro hydrocarbon alcohol are used as raw materials to undergo esterification reaction, and then the mixture is subjected to difluoroamination reaction with tetramethyl difluoroaminosulfonate to obtain the energetic plasticizer.

3. The method for preparing a difluoroamino energetic plasticizer according to claim 2, wherein: The preparation method is carried out according to the following reaction formula:

4. The method for preparing a difluoroamino energetic plasticizer according to claim 3, wherein: The following steps are involved: Step 1: reacting a compound of formula I with a nitroalkyl alcohol in dichloromethane to obtain a compound of formula II, 1,3-acetonedicarboxylic acid nitroalkyl ester; At room temperature, the compound of formula I and the nitroalkyl alcohol are added to dichloromethane and stirred, and a small amount of concentrated sulfuric acid is added. After the addition is complete, the reaction system is heated to 60° C. and refluxed for 8-10 hours. After the reaction is completed, the temperature is lowered to room temperature, water is added to the reaction and stirring is continued. The organic phase is collected, the aqueous phase is extracted with dichloromethane, and the organic phases are combined. The extracted organic phase is washed with sodium bicarbonate solution and pure water, and dried and spin-dried to obtain the intermediate product compound of formula II. Step 2: Mix the compound of formula II and tetramethyl difluoroaminosulfonate to undergo difluoroamination reaction to obtain a compound of formula AFE The compound of formula II and tetramethyldifluorosulfamate are added to dichloromethane, and fuming sulfuric acid is added at 0°C. After the reaction is completed, the reaction solution is poured into ice water, the organic phase is separated, the aqueous phase is extracted with dichloromethane, and the organic phases are combined; the extracted organic phase is washed with sodium bicarbonate solution and pure water, and dried and spin-dried to obtain the product.

5. The method for preparing a difluoroamino energetic plasticizer according to claim 4, wherein: In the step 1, the molar ratio of 1,3-acetone dicarboxylic acid to nitro hydrocarbon alcohol is 1:2-10, and the amount of concentrated sulfuric acid added is 10%-30% of the mass of the alcohol added.

6. The method for preparing a difluoroamino energetic plasticizer according to claim 4, wherein: In the step 2, in the reaction for preparing the compound of formula AFE, the molar ratio of the compound of formula II to the difluorosulfamate is 1:2-10.

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