A3 plasticizer substitute and synthesis method thereof
By introducing azide groups into A3 plasticizer, gem-diazido acetal compounds were synthesized, solving the problems of high glass transition temperature and viscosity, and achieving improved mechanical properties and energy retention of solid propellants at low temperatures.
Patent Information
- Application Number
- CN202511538262.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-27
- Publication Date
- 2026-01-30
AI Technical Summary
The existing A3 plasticizer has a high glass transition temperature, which leads to poor mechanical properties of solid propellants at low temperatures, limiting its widespread application. At the same time, the high viscosity causes the filler inside the propellant to not solidify, resulting in a "sandwich" phenomenon. In addition, increasing the plasticizer content will reduce the propellant energy.
By introducing azide groups to replace nitro groups, novel gem-diazido acetal energetic compounds are synthesized. By adjusting the molecular structure, the glass transition temperature and viscosity are reduced, while the nitrogen content and enthalpy of formation are increased.
The synthesized BDAPF compound has a low glass transition temperature of -95.3℃ and a high enthalpy of formation of 773.2 kJ/mol, showing good application prospects as a substitute for A3 plasticizer in solid propellants.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of energetic materials, and relates to an A3 plasticizer substitute and a synthesis method thereof. BACKGROUND
[0002] BDNPF / A is one of the typical energetic plasticizers (also known as A3 plasticizer), which has low vapor pressure, suitable density, good thermal stability and compatibility, and has been applied in insensitive propellants and explosive formulations. It can improve the pouring effect of propellants and significantly improve the mechanical properties and burning rate. However, in the research, it was found that the higher viscosity of the plasticizer led to the "sandwich" phenomenon of the un-solidified filler in the charge, and increasing the content of the plasticizer to improve it would bring the decrease of the content of the solid high-energy component, which limited the improvement of the energy of the propellant. In addition, the higher glass transition temperature (-65℃) of the A3 plasticizer led to poor low-temperature mechanical properties of the solid propellant, which limited its popularization and application.
[0003] Based on the geminal dinitro unit, researchers have developed a variety of A3 substitutes and conducted performance research by adjusting the carbon chain structure or end group. Cho Jin Rai et al. reported that the binary energetic plasticizer composed of BDNPDF and BDNPF could improve the problem of crystallization of the latter, and the product did not crystallize after being placed at -20℃ for 6 months (USP 6592692, 2003). In the same year, the team proposed that a mixture of BDNPF / BDNBF (bis (2, 2-dinitrobutyl) formal) / DNBPF (2, 2-dinitropropyl-2, 2-dinitrobutyl formal) with controllable proportions could be obtained by co-acetalization of 2, 2-dinitropropanol and 2, 2-dinitrobutanol in a certain proportion. The energy of the mixed plasticizer is equivalent to that of A3, and the thermal stability is improved (USP 6620268, 2003). However, the above two plasticizers did not improve the key properties of viscosity and glass transition temperature. Liu Yajing et al. reported a class of ester plasticizers DNPAc, DNPPc, and DNPBc with geminal dinitro units in the synthesis and performance of geminal dinitro insensitive plasticizers, Applied Chemistry, 2020, 49(7): 1693-1696. The decomposition temperature and impact sensitivity are equivalent to those of A3, and the enthalpy of formation and glass transition temperature are much better than those of A3, but the chemical instability of the ester structure leads to the problem of incompatibility with the liner in practical application. SUMMARY
[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide an A3 plasticizer substitute and a synthesis method thereof, and to effectively reduce the plasticizer viscosity and glass transition temperature, and improve the nitrogen content and enthalpy of formation by introducing an azide group into the molecule in view of the problem that the current A3 plasticizer has a high glass transition temperature, so that the present application proposes a novel geminal diazide acetal energetic compound in which the azide group completely replaces the nitro group, which has a similar structure to A3, good plasticizing ability, a low glass transition temperature of -95.3 DEG C, and a high enthalpy of formation of 773.2 kJ / mol (the BDNPF is -459.4 kJ / mol), and can be used as an A3 plasticizer substitute for solid propellants, and has good application prospects in solid propellants.
[0005] In order to solve the above technical problems, the present application adopts the following technical solutions to achieve: A synthesis method of an A3 plasticizer substitute, and the synthesis route is as follows: .
[0006] The present application also includes the following technical features: Specifically, the following steps are included: Step 1, dissolve nitroethane in sodium hydroxide aqueous solution, add formaldehyde under ice water bath, stir for 2-4 h, then drop into methanol solution containing liquid bromine, and stir under ice bath for 2-4 h; after the reaction is completed, the product 2-bromo-2-nitropropanol BNPOH is obtained by extraction with organic solvent A, water washing, and distillation and concentration; Step 2, dissolve BNPOH and trioxymethylene in organic solvent B, slowly drop concentrated sulfuric acid under the condition of 0-20 DEG C, continue to stir for 0.5-2 h after the dropping is completed, separate the reaction mixture after the reaction is completed, extract the acid phase with organic solvent B, wash the combined organic phase to neutral, and distill and concentrate to obtain the product bis(2-bromo-2-nitropropanol) formaldehyde BBNPF; Step 3, dissolve BBNPF in organic solvent C, add sodium azide, and stir at 80 DEG C for 6-8 h; after the reaction is completed, the product bis(2,2-diazidopropanol) formaldehyde BDNPF is obtained by extraction with dichloromethane, water washing, and distillation and concentration.
[0007] Specifically, the molar ratio of sodium hydroxide, nitroethane and formaldehyde is 1.05:1:1-1.2, and the molar ratio of nitroethane and liquid bromine is 1:1; The molar ratio of BNPOH and trioxymethylene is 6.2-6:1; The molar ratio of BBNPF and sodium azide is 1:4-6.
[0008] Specifically, the organic solvent A includes diethyl ether, dichloromethane, and ethyl acetate.
[0009] Specifically, the organic solvent B includes dichloromethane, dichloroethane.
[0010] Specifically, the organic solvent C includes dimethyl sulfoxide, N,N-dimethylformamide, polyethylene glycol 400 and a mixed solution thereof with water.
[0011] An A3 plasticizer substitute is prepared by the synthetic method of the A3 plasticizer substitute; the structural formula is: .
[0012] Compared with the prior art, the present application has the following technical effects: The present application synthesizes a novel gem-diazido acetal energetic compound, which has a structure similar to A3, and has a low glass transition temperature and a high enthalpy of formation compared with the latter, and can be used as an A3 plasticizer substitute, and has a good application prospect in solid propellants. BRIEF DESCRIPTION OF DRAWINGS
[0013] Figure 1 It is an infrared spectrum of the BDAPF.
[0014] Figure 2 It is a nuclear magnetic hydrogen spectrum of the BDAPF.
[0015] Figure 3 It is a nuclear magnetic carbon spectrum of the BDAPF. DETAILED DESCRIPTION
[0016] The present application provides an A3 plasticizer substitute and a synthetic method thereof, and the structure and route are as follows:
[0017] The preparation method of the energetic compound comprises the following steps: (1) Dissolve nitroethane in a sodium hydroxide aqueous solution, add formaldehyde under ice water bath, stir for 2-4 h, and then drop into a liquid bromine methanol solution, and stir for 2-4 h under ice bath. After the reaction is completed, the product 2-bromo-2-nitropropanol (BNPOH) is obtained by extraction with an organic solvent A, water washing and distillation concentration.
[0018] (2) Dissolve BNPOH and trioxane in an organic solvent B, slowly drop concentrated sulfuric acid under the condition of 0-20 DEG C, continue to stir for 0.5-2 h after the dropping is completed, separate the liquid after the reaction is completed, extract the acid phase with an organic solvent B, wash the combined organic phase to neutral, and distill and concentrate to obtain the product bis (2-bromo-2-nitropropanol) formal (BBNPF).
[0019] (3) BBNPF is dissolved in organic solvent C, sodium azide is added, and stirring is carried out at 80 DEG C for 6-8 h. After the reaction is completed, dichloromethane is extracted, washed with water, and concentrated by distillation to obtain a light yellow liquid, and column chromatography is used to separate the product bis (2, 2-diazidopropanol) formaldehyde (BDAPF).
[0020] In the above step, the molar ratio of sodium hydroxide, nitroethane and formaldehyde is 1.05:1:1-1.2, and the molar ratio of nitroethane and liquid bromine is 1:1; In the above step, the molar ratio of BNPOH and trioxymethylene is 6.2-6:1; In the above step, the molar ratio of BBNPF and sodium azide is 1:4-6; In the above step, the organic solvent A includes but is not limited to diethyl ether, dichloromethane, ethyl acetate and the like, and different solvents have a great influence on the yield of BNPOH; In the above step, the organic solvent B includes but is not limited to dichloromethane, dichloroethane and the like, and different solvents have a great influence on the purity and yield of BBNPF; In the above step, the organic solvent C includes but is not limited to dimethyl sulfoxide, N, N-dimethylformamide, polyethylene glycol 400 and the like and a mixed solution thereof with water, and different solvents determine the composition and content of the reaction by-products.
[0021] The product BDAPF of the present application has a geminal diazido energetic unit, which can better improve the nitrogen content and enthalpy of formation of the compound, reduce the glass transition temperature, and can be used as an A3 plasticizer substitute for solid propellants, and has good application prospect.
[0022] The following gives specific embodiments of the present application, and it should be noted that the present application is not limited to the following specific embodiments, and any equivalent transformation made on the basis of the technical solutions of the present application falls within the protection scope of the present application.
[0023] Example 1: The present embodiment provides an A3 plasticizer substitute and a synthesis method thereof, comprising: (1) 15 g of nitroethane is dissolved in 30 mL of an aqueous solution containing 8.4 g of sodium hydroxide, 17.5 g of 37% formaldehyde aqueous solution is added at 0-5 DEG C, and stirring is carried out for 2 h. After the reaction is completed, the liquid is dropped into a mixture of 40 mL of methanol and 32 g of liquid bromine at 5-10 DEG C, and stirring is carried out for 3 h. After the reaction is completed, ethyl acetate is used for extraction, washed with water, and concentrated by distillation to obtain 33 g of product BNPOH.
[0024] (2) Dissolve 11.5g BNPOH and 0.9g trioxymethane in dichloromethane, slowly add concentrated sulfuric acid at 0~5℃, and continue stirring for 2h after the addition is complete. After the reaction is complete, separate the liquid and extract the acid phase with dichloromethane. After combining the organic phases, wash with water until neutral, and distill to concentrate to obtain 10g of white waxy solid product bis(2-bromo-2-nitropropanol)formaldehyde (BBNPF).
[0025] (3) Dissolve 7.6g of BBNPF in polyethylene glycol 400:water (mass ratio 3:1), add 6.5g of sodium azide, and stir at 80℃ for 7h. After the reaction is complete, extract with dichloromethane, wash with water, and concentrate by distillation to obtain 4g of light yellow liquid. Column chromatography is used to separate the product bis(2,2-diazidopropanol)formaldehyde (BDAPF).
[0026] Characterization test results as follows Figure 1 , 2 As shown in Figure 3, Figure 1 The infrared spectrum of BDAPF. Figure 2 The image shows the hydrogen NMR spectrum of BDAPF. Figure 3 The image shows the carbon NMR spectrum of BDAPF. Both the hydrogen and carbon NMR spectra indicate the synthesis of the target compound. Specific results are as follows: 1 H NMR (500 MHz, d6-DMSO, 298 K) delta (ppm): 1.50, 3.74, 4.82.
[0027] 13 C NMR (125 MHz, d6-DMSO, 298 K) delta (ppm): 21.40, 72.62, 81.10, 95.67.
[0028] Example 2: This embodiment provides an A3 plasticizer substitute and its synthesis method, including: (1) Dissolve 15g of nitroethane in 30mL of an aqueous solution containing 8.4g of sodium hydroxide, add 17.5g of 37% formaldehyde aqueous solution at 0-5℃, and stir for 2h. After the reaction is complete, add the above solution dropwise to a mixed solution of 40mL of methanol and 32g of liquid bromine at 5-10℃, and stir for 3h. After the reaction is complete, extract with diethyl ether, wash with water, and concentrate by distillation to obtain 30g of product BNPOH.
[0029] (2) 11.5 g of BNPOH and 0.9 g of trioxane were dissolved in dichloromethane, and concentrated sulfuric acid was slowly added at 5-10°C. After the addition was completed, stirring was continued for 1 h. After the reaction was completed, the liquid was separated, the acid phase was extracted with dichloromethane, the combined organic phase was washed with water until neutral, and then concentrated by distillation to obtain 9.5 g of a white waxy solid product bis(2-bromo-2-nitropropanol) formal (BBNPF).
[0030] (3) 7.6 g of BBNPF was dissolved in polyethylene glycol 400: water (mass ratio 4:1), 6.5 g of sodium azide was added, and stirring was carried out at 80°C for 6 h. After the reaction was completed, dichloromethane was used for extraction, water was used for washing, and then concentrated by distillation to obtain 3.2 g of a light yellow liquid. Column chromatography was used for separation to obtain the product bis(2,2-diazidopropanol) formal (BDAPF).
[0031] Example 3: The present embodiment provides an A3 plasticizer substitute and a synthesis method thereof, which comprises: (1) 15 g of nitroethane was dissolved in 30 mL of an aqueous solution containing 8.4 g of sodium hydroxide, 17.5 g of 37% formaldehyde aqueous solution was added at 0-5°C, and stirring was carried out for 2 h. After the reaction was completed, the liquid was added dropwise into a mixed solution of 40 mL of methanol and 32 g of liquid bromine at 5-10°C, and stirring was carried out for 3 h. After the reaction was completed, dichloromethane was used for extraction, water was used for washing, and then concentrated by distillation to obtain 24 g of the product BNPOH.
[0032] (2) 11.5 g of BNPOH and 0.9 g of trioxane were dissolved in dichloromethane, and concentrated sulfuric acid was slowly added at 0-5°C. After the addition was completed, stirring was continued for 2 h. After the reaction was completed, the liquid was separated, the acid phase was extracted with dichloromethane, the combined organic phase was washed with water until neutral, and then concentrated by distillation to obtain 9 g of a light pink waxy solid product bis(2-bromo-2-nitropropanol) formal (BBNPF).
[0033] (3) 7.6 g of BBNPF was dissolved in dimethyl sulfoxide, 7.8 g of sodium azide was added, and stirring was carried out at 80°C for 8 h. After the reaction was completed, dichloromethane was used for extraction, water was used for washing, and then concentrated by distillation to obtain 2 g of an orange liquid. Column chromatography was used for separation to obtain the product bis(2,2-diazidopropanol) formal (BDAPF).
[0034] Example 4: The present embodiment provides an A3 plasticizer substitute and a synthesis method thereof, which comprises: (1) 15 g of nitroethane was dissolved in 30 mL of an aqueous solution containing 8.4 g of sodium hydroxide, 17.5 g of 37% aqueous formaldehyde was added at 0~5°C, and the reaction was stirred for 2 h. After the reaction was completed, the solution was added dropwise into a mixed solution of 40 mL of methanol and 32 g of liquid bromine at 5~10°C, and the reaction was stirred for 3 h. After the reaction was completed, extraction was performed using ethyl acetate, washed with water, and concentrated by distillation to obtain 33 g of the product BNPOH.
[0035] (2) 11.5 g of BNPOH and 0.9 g of trioxane were dissolved in dichloromethane, and concentrated sulfuric acid was slowly added at 0~5°C. After the addition was completed, the reaction was stirred for 2 h, the reaction was completed, and the liquid was separated. The acid phase was extracted with dichloromethane, the combined organic phase was washed with water until neutral, and concentrated by distillation to obtain 10 g of the product bis(2-bromo-2-nitropropanol) formal (BBNPF).
[0036] (3) 7.6 g of BBNPF was dissolved in N,N-dimethylformamide, 6 g of sodium azide was added, and the reaction was stirred at 80°C for 6 h. After the reaction was completed, extraction was performed using dichloromethane, washed with water, and concentrated by distillation to obtain 2.3 g of a light yellow liquid. Column chromatography was performed to separate the product bis(2,2-diazidopropanol) formal (BDAPF).
Claims
1. A method of synthesis of an A3 plasticizer substitute, characterized by, The synthetic route is: 。 2. The method of synthesis of A3 plasticizer substitute as claimed in claim 1 wherein, Comprising the following steps: Step 1, nitroethane is dissolved in sodium hydroxide aqueous solution, formaldehyde is added under ice water bath, after stirring for 2-4 h, liquid bromine in methanol solution is added dropwise, and stirring is carried out under ice bath for 2-4 h; after the reaction is completed, the product 2-bromo-2-nitropropanol BNPOH is obtained by extraction with organic solvent A, water washing, and distillation concentration; Step 2, BNPOH and trioxane are dissolved in organic solvent B, and concentrated sulfuric acid is slowly added dropwise under the condition of 0-20℃, after the dropwise addition is completed, stirring is continued for 0.5-2 h, after the reaction is completed, the liquid is separated, the acid phase is extracted with organic solvent B, the combined organic phase is washed to neutral, and distillation concentration is carried out to obtain the product bis(2-bromo-2-nitropropanol) formaldehyde BBNPF; Step 3, BBNPF is dissolved in organic solvent C, sodium azide is added, and stirring is carried out at 80℃ for 6-8 h; after the reaction is completed, dichloromethane extraction, water washing, and distillation concentration are carried out to obtain a light yellow liquid, column chromatography separation is carried out to obtain the product bis(2,2-diazidopropanol) formaldehyde BDAPF.
3. The method of synthesis of A3 plasticizer substitute as claimed in claim 2 wherein, The molar ratio of sodium hydroxide, nitroethane and formaldehyde is 1.05:1:1-1.2, and the molar ratio of nitroethane and liquid bromine is 1:1; The molar ratio of BNPOH and trioxane is 6.2-6:1; The molar ratio of BBNPF and sodium azide is 1:4-6.
4. The method of synthesis of A3 plasticizer substitute as claimed in claim 2, wherein, The organic solvent A includes diethyl ether, dichloromethane, ethyl acetate.
5. The method of synthesis of A3 plasticizer substitute as claimed in claim 2, wherein, The organic solvent B includes dichloromethane and dichloroethane.
6. The method of synthesis of A3 plasticizer substitute as claimed in claim 2, wherein, The organic solvent C includes dimethyl sulfoxide, N,N-dimethylformamide, polyethylene glycol 400 and a mixed solution thereof with water.
7. An A3 plasticizer substitute, characterized in that, The A3 plasticizer substitute is prepared by the synthetic method of any one of claims 1 to 6, and has the structural formula: The synthetic route is: 。