Bicyclo [1.1. 1] pentane-1, 3-dimethylene dinitrate as well as preparation method and application thereof

Abstract

The invention provides bicyclo [1.1. 1] pentane-1, 3-dimethylene dinitrate as well as a preparation method and application thereof, and belongs to the technical field of functional materials. The invention aims to solve the technical problems of insufficient energy density, poor thermal stability or complex synthesis process of plasticizers. The preparation method comprises the following steps: (1) carrying out esterification reaction on a compound 1 to obtain a compound 2; (2) mixing the compound 2, a reducing agent and a solvent for reduction reaction to obtain a compound 3; and (3) nitrating the compound 3 to obtain a product compound 4. According to the bicyclo [1.1. 1] pentane-1, 3-dimethylene dinitrate, high-tension propeller alkane is used as a framework, meanwhile, a nitrate ester functional group is introduced, and the bicyclo [1.1. 1] pentane-1, 3-dimethylene dinitrate has high energy density and good thermal stability and can be used as an energetic plasticizer in a solid propellant. Compared with a traditional plasticizer DEHA, the mechanical property and the thermal stability of a sample strip cured in an HTPB-TDI system are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials, and in particular relates to bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate. Background Art

[0002] Solid propellant is a composite material composed of energetic components such as metal fuel and oxidizer encapsulated by a binder. As the power source for missiles and spacecraft, it is a core component of solid rocket propulsion systems. Its energy characteristics directly determine the carrying capacity of the equipment. Therefore, while ensuring mechanical and thermomechanical properties, continuously improving propellant energy and developing high-energy insensitive propellants have become the main development directions in the solid propellant field.

[0003] The binder system accounts for approximately 10-15% of the composition of solid propellants. Its function is to react with the curing agent under specific temperature conditions to form an elastomer, thereby bonding the other components. The properties of the binder have a significant impact on the energy level and mechanical properties of the propellant. Currently, hydroxy-terminated polybutadiene (HTPB) is the most commonly used binder system.

[0004] Plasticizers are used to improve the plasticity of solid propellants. Currently, traditional plasticizers (such as dioctyl adipate (DOA), diisooctyl adipate (DEHA), dioctyl phthalate (DOP), and dioctyl sebacate (DOS)) are mostly inert plasticizers. While they can improve the processing properties of propellants, they also reduce their energy performance. While existing energetic plasticizers can compensate for energy loss, they suffer from poor compatibility with binder systems, resulting in decreased low-temperature performance and mechanical properties. Therefore, there is an urgent need to develop new energetic plasticizers suitable for solid propellant binder systems to achieve both energy and insensitivity in propellants. Summary of the Invention

[0005] To address the technical issues of insufficient energy density, poor thermal stability, or complex synthesis processes of plasticizers, the present invention proposes a bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, its preparation method, and application. Compared with the traditional plasticizer DEHA, the compound prepared in the present invention exhibits significant advantages in the HTPB-TDI system, significantly improving the mechanical properties and thermal stability of the cured specimens.

[0006] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] A bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate having the following structure:

[0008]

[0009] A method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, wherein the synthesis route of the bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate is:

[0010]

[0011] The preparation method comprises the following steps:

[0012] (1) Compound 1 is subjected to esterification reaction to obtain compound 2;

[0013] (2) Compound 2, a reducing agent, and a solvent are mixed to undergo a reduction reaction to obtain Compound 3;

[0014] (3) Compound 3 is nitrated to obtain the product compound 4.

[0015] The esterification reaction in step (1) is as follows: adding compound 1 to an alcohol reagent and reacting at 50-80° C. for 6-12 hours.

[0016] The alcohol reagent is methanol; the mass ratio of the compound 1 to the alcohol reagent is 1:2-5.

[0017] The step (2) is specifically as follows: dissolving compound 2 in a solvent, cooling to -20 to 0°C, adding a reducing agent dropwise under the protection of an inert gas, and reacting at room temperature for 2 to 5 hours after the addition is complete.

[0018] The solvent is tetrahydrofuran; the mass ratio of the compound 2 to the solvent is 1:5-20.

[0019] The reducing agent is one of lithium aluminum hydride, lithium borohydride or diisobutylaluminum hydride, and the molar ratio of the compound 2 to the reducing agent is 1:1 to 1.5.

[0020] In the step (3), fuming nitric acid-acetic anhydride is used for nitration.

[0021] The molar ratio of compound 3 to fuming nitric acid is 1:2-10, and the molar ratio of fuming nitric acid to acetic anhydride is 1:2-5. The addition temperature is -20-0°C, the reaction temperature is room temperature, and the reaction time is 1-5 hours. The room temperature is 10-30°C. Compound 4 has a melting point of 28.5°C and can be crystallized at low temperature and further purified by washing with ice water.

[0022] The bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate is used in solid propellants. The bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate is used as a plasticizer in the formulation of HTPB-based solid propellants.

[0023] The bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate can be directly used to prepare propellant adhesive elastomers. The specific operation is as follows:

[0024] The formulated amount of bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate plasticizer and HTPB prepolymer were weighed and evenly mixed, stirred at 60°C for 1 hour, and then TDI curing agent was added. The mixture was stirred at 60°C for 0.5 hour, and the bubbles were removed by vacuum. The mixture was transferred to a polytetrafluoroethylene mold and cured at 60°C for 5 days to obtain an HTPB elastomer.

[0025] Beneficial effects of the present invention:

[0026] (1) Bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate has the characteristics of high energy density and good thermal stability, and is a propellerane energetic material;

[0027] (2) The preparation process of bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate is characterized by simple operation and easy purification;

[0028] (3) Bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate can plasticize HTPB. Compared with the traditional plasticizer DEHA, the mechanical properties and thermal stability of the specimens after curing in the HTPB-TDI system are improved, and the energy is much greater than that of DEHA. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 The product obtained in Example 1 of the present invention 1 H-NMR spectrum.

[0031] Figure 2 The product obtained in Example 1 of the present invention 13 C-NMR spectrum.

[0032] Figure 3 This is a diagram of the molecular structure of the product obtained in Example 1 of the present invention.

[0033] Figure 4 TG graph of the cured strips of the product obtained in Example 1 of the present invention and DEHA. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0035] A method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, the synthetic route is:

[0036]

[0037] The specific implementation method has the following three steps:

[0038] (1) Esterification reaction: accurately weigh a certain amount of compound 1 in a reaction vessel, add methanol, start stirring, heat to 50-80°C, react for 6-12 hours, and after the reaction is completed, cool to room temperature, remove the solvent by rotary evaporation until solid precipitates, place at 0°C to cool and crystallize, filter, and dry to obtain compound 2.

[0039] (2) Reduction reaction: Accurately weigh a certain amount of compound 2 into a reaction vessel, add anhydrous tetrahydrofuran under inert gas protection, place in a -20 to 0°C low-temperature reactor, slowly dropwise add the reducing agent tetrahydrofuran solution, after the addition is complete, react at room temperature for 2 to 5 hours, after the reaction is complete, slowly add 5% sodium hydroxide solution at 0°C, continue stirring for 0.5 hours, then add desiccant, stir for 0.5 hours, filter, collect the filtrate, and concentrate by rotary evaporation to obtain compound 3.

[0040] (3) Nitration reaction: Accurately weigh a certain amount of acetic anhydride into a reaction vessel, slowly add fuming nitric acid at -20 to 0°C, stir for 10 minutes, and then slowly add compound 3 dropwise. After the addition is complete, stir and react at room temperature for 1 to 5 hours. Pour the reaction liquid into ice water and stir for 0.5 hours. Then extract with ether three times, collect the organic phase, dry it, and concentrate it to obtain the final product, compound 4. The melting point of compound 4 is 28.5°C. Place it in the refrigerator to obtain a white solid.

[0041] Example 1

[0042] A method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, the synthetic route is:

[0043]

[0044] The specific steps are:

[0045] Accurately weigh 15.6 g (0.1 mol) of compound 1 into a 100 mL flask, add 48 g of methanol, start stirring, rotate at 500 rpm, and reflux at 60 ° C for 10 h. After the reaction is completed, cool to room temperature, remove the solvent by rotary evaporation at 30 ° C until solid precipitates, place at 0 ° C overnight to cool and crystallize, filter, and dry the obtained solid to obtain 15.3 g of compound 2, with a yield of 83%.

[0046] Accurately weigh 9.2 g (0.05 mol) of compound 2 into a 100 mL flask, add 82 g of anhydrous tetrahydrofuran, replace the air in the flask with nitrogen, seal it, place it in a -10 ° C low-temperature reactor, start stirring, and add 24 mL of lithium aluminum tetrahydride (2.5 M tetrahydrofuran solution, 0.06 mol) dropwise. After the addition is complete, react at room temperature for 4 h, then slowly add 10 mL of 5% sodium hydroxide solution at 0 ° C, continue stirring for 0.5 h, add 10 g of anhydrous magnesium sulfate, stir for 0.5 h, filter, collect the filtrate, and concentrate it by rotary evaporation to obtain 4.9 g of colorless oily liquid (compound 3) with a yield of 77%.

[0047] Accurately weigh 4.9 g (0.048 mol) of acetic anhydride into a 50 mL flask, place it in a -10 ° C low-temperature reactor, start stirring, slowly add 1 g (0.016 mol) of fuming nitric acid and 0.51 g (0.004 mol) of compound 3 in sequence, then leave it to react at room temperature for 3 h, pour the reaction liquid into 20 mL of ice water and stir for 0.5 h, then extract with ether (20 mL × 3), collect the organic phase, dry it with anhydrous sodium sulfate, and concentrate it to obtain a yellow oily liquid, place it in the refrigerator overnight, wash it with ice water (20 mL × 3), filter and collect the solid, and dry it to obtain 0.63 g of viscous liquid with a yield of 72%.

[0048] That 1 H-NMR spectrum, 13 C-NMR spectrum Figure 1 、 2 As shown, the data is as follows: 1 H NMR(500MHz,DMS O-d6)δ4.56(s,4H),1.79(s,6H); 13 C NMR (126MHz, DMSO-d6) δ72.28, 49.37, 36.66; Elemental Analysis calculated: C 38.54, H 4.62, N 12.84%; analyzed: C 38.77, H 4.31, N 12.87%; C 38.88, H 4.38, N 12.84%. The molecular structure of bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate was finally determined as follows Figure 3 shown.

[0049] Example 2

[0050] A method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, the synthetic route is:

[0051]

[0052] The specific steps are:

[0053] Accurately weigh 15.6 g (0.1 mol) of compound 1 into a 100 mL flask, add 31 g of methanol, start stirring, rotate at 500 rpm, and reflux at 80°C for 6 h. After the reaction is completed, cool to room temperature, remove the solvent by rotary evaporation at 30°C until solid precipitates, place at 0°C overnight to cool and crystallize, filter, and dry the obtained solid to obtain 14.7 g of compound 2, with a yield of 80%.

[0054] Accurately weigh 9.2 g (0.05 mol) of compound 2 into a 250 mL flask, add 47.5 g of anhydrous tetrahydrofuran, replace the air in the flask with nitrogen, seal it, place it in a 0 ° C low-temperature reactor, start stirring, and add 25 mL of lithium borohydride (2M tetrahydrofuran solution, 0.05 mol) dropwise. After the addition is complete, react at room temperature for 2 h, then slowly add 10 mL of 5% sodium hydroxide solution at 0 ° C, continue stirring for 0.5 h, add 10 g of anhydrous magnesium sulfate, stir for 0.5 h, filter, collect the filtrate, and concentrate it by rotary evaporation to obtain 3.8 g of colorless oily liquid (compound 3), with a yield of 60%.

[0055] Accurately weigh 1.6 g (0.016 mol) of acetic anhydride into a 50 mL flask, place it in a -10 ° C low-temperature reactor, start stirring, and slowly add 0.5 g (0.008 mol) of fuming nitric acid and 0.51 g (0.004 mol) of compound 3 in sequence. Then, let it react at room temperature for 2 h. The reaction liquid was poured into 20 mL of ice water and stirred for 0.5 h. Then, it was extracted with ether (20 mL × 3). The organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain a yellow oily liquid. It was placed in a refrigerator overnight and washed with ice water (20 mL × 3). The solid was collected by filtration and dried to obtain 0.57 g of viscous liquid with a yield of 65%.

[0056] That 1 H-NMR spectrum, 13 The C-NMR spectrum was consistent with that of Example 1.

[0057] Example 3

[0058] A method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, the synthetic route is:

[0059]

[0060] The specific steps are:

[0061] Accurately weigh 15.6 g (0.1 mol) of compound 1 into a 250 mL flask, add 78 g of methanol, start stirring, rotate at 500 rpm, and reflux at 50 ° C for 12 h. After the reaction is completed, cool to room temperature, remove the solvent by rotary evaporation at 30 ° C until solid precipitates, place at 0 ° C overnight to cool and crystallize, filter, and dry the obtained solid to obtain 15.1 g of compound 2 with a yield of 82%.

[0062] Accurately weigh 9.2 g (0.05 mol) of compound 2 into a 500 mL flask, add 184 g of anhydrous tetrahydrofuran, replace the air in the flask with nitrogen, seal it, place it in a -20 ° C low-temperature reactor, start stirring, and add 75 mL of sodium borohydride (1 M tetrahydrofuran solution, 0.075 mol) dropwise. After the addition is complete, react at room temperature for 5 h, then slowly add 10 mL of 5% sodium hydroxide solution at 0 ° C, continue stirring for 0.5 h, add 10 g of anhydrous magnesium sulfate, stir for 0.5 h, filter, collect the filtrate, and concentrate it by rotary evaporation to obtain 3.05 g of colorless oily liquid (compound 3) with a yield of 48%.

[0063] Accurately weigh 10.3 g (0.1 mol) of acetic anhydride into a 50 mL flask, place it in a -10 ° C low-temperature reactor, start stirring, and slowly add 1.26 g (0.02 mol) of fuming nitric acid and 0.51 g (0.004 mol) of compound 3 in sequence. Then, let it react at room temperature for 5 h. The reaction liquid was poured into 20 mL of ice water and stirred for 0.5 h. Then, it was extracted with ether (20 mL × 3). The organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain a yellow oily liquid. It was placed in a refrigerator overnight, washed with ice water (20 mL × 3), and the solid was collected by filtration and dried to obtain 0.61 g of viscous liquid with a yield of 70%.

[0064] That 1 H-NMR spectrum, 13 The C-NMR spectrum was consistent with that of Example 1.

[0065] From the above three examples, it can be seen that the first step reaction is relatively stable. Using methanol as the solvent, temperature and reaction time have little effect on the yield. The yield of the second step varies greatly, mainly related to the type of reducing agent. Among them, lithium aluminum tetrahydride has a strong reducing ability and can effectively reduce the ester to alcohol. The yield of the third step reaction is relatively stable, and the reaction is completed within 2 hours.

[0066] Application Examples

[0067] Bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate (Compound 4) was used as a plasticizer to prepare solidified bars. The preparation method of the solidified bars was as follows:

[0068] (1) Add the plasticizer to HTPB at a mass ratio of 1:10 and stir at 60°C for 1 h.

[0069] (2) Add TDI (toluene diisocyanate) with a mass ratio of 0.7:1 to plasticizer and continue stirring at 60°C for 30 minutes.

[0070] (3) Vacuum and remove bubbles at 60℃ for 20 minutes.

[0071] (4) Use a pipette to drip onto a preheated mold and cure at 60°C under normal pressure for 3 days.

[0072] Comparative Example

[0073] DEHA (di(2-ethylhexyl) phthalate) was used as a plasticizer to prepare solidified bars. The preparation method of the solidified bars was as follows:

[0074] (1) Add the plasticizer to HTPB at a mass ratio of 1:10 and stir at 60°C for 1 h.

[0075] (2) Add TDI in a mass ratio of 0.7:1 to plasticizer and continue stirring at 60°C for 30 minutes.

[0076] (3) Vacuum and remove bubbles at 60℃ for 20 minutes.

[0077] (4) Use a pipette to drip onto a preheated mold and cure at 60°C under normal pressure for 3 days.

[0078] Performance testing was performed on the cured bars. The test results, shown in Table 1, show that the glass transition temperature of the material plasticized with Compound 4 is comparable to that of the material plasticized with DEHA. However, the maximum load, tensile strength, and elongation at break of the bars cured with Compound 4 plasticizer were all greater than those prepared with DEHA. The thermal stability was also higher than that of the bars prepared with DEHA, indicating that Compound 4 has significant advantages in mechanical properties and thermal stability.

[0079] Further thermal analysis of the cured specimens was performed, and the results were as follows: Figure 4 The initial thermal decomposition temperature (Tonset) of the cured specimens plasticized with Compound 4 is lower than that of the DEHA-cured specimens. This is because the thermal decomposition temperature of Compound 4 is 197.6°C, while the boiling point of DEHA is 214°C. However, as the temperature continues to rise, the mass loss rate of the cured specimens plasticized with Compound 4 slows significantly, and the starting point of the second thermal decomposition curve is higher than that of the DEHA-cured specimens, indicating better thermal stability.

[0080] Table 1 Thermomechanical properties of cured specimens

[0081]

[0082]

[0083] Note: [a ]Glass transition temperature; [b ] Cross-link density; [c ]Decomposition temperature; [d ]Maximum load; [e ]tensile strength; [f ]The elongation at break is shown in Table 2. The physical and chemical properties of bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate were tested.

[0084] Table 2 Physicochemical properties of bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate

[0085]

[0086] Note: [a ] melting point; [b ]Starting decomposition temperature; [c ]Single crystal density; [d Viscosity

[0087] Example 4

[0088] A method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, the synthetic route is:

[0089]

[0090] The specific steps are:

[0091] Accurately weigh 15.6 g (0.1 mol) of compound 1 into a 100 mL flask, add 31.2 g of methanol, start stirring, rotate at 500 rpm, and reflux at 80 ° C for 6 h. After the reaction is completed, cool to room temperature, remove the solvent by rotary evaporation at 30 ° C until solid precipitates, place at 0 ° C overnight to cool and crystallize, filter, and dry the obtained solid to obtain 14.8 g of compound 2, with a yield of 80%.

[0092] Accurately weigh 9.2 g (0.05 mol) of compound 2 into a 500 mL flask, add 184 g of anhydrous tetrahydrofuran, replace the air in the flask with nitrogen, seal it, place it in a -5 ° C low-temperature reactor, start stirring, and add 20 mL of lithium aluminum tetrahydride (2.5 M tetrahydrofuran solution, 0.05 mol) dropwise. After the addition is complete, react at room temperature for 5 h, then slowly add 20 mL of 5% sodium hydroxide solution at 0 ° C, continue stirring for 0.5 h, add 15 g of anhydrous magnesium sulfate, stir for 0.5 h, filter, collect the filtrate, and concentrate it by rotary evaporation to obtain 4.8 g of colorless oily liquid (compound 3) with a yield of 75%.

[0093] Accurately weigh 4.1 g (0.04 mol) of acetic anhydride into a 50 mL flask, place it in a -10 ° C low-temperature reactor, start stirring, slowly add 0.5 g (0.008 mol) of fuming nitric acid and 0.51 g (0.004 mol) of compound 3 in sequence, then leave it to react at room temperature for 5 h. The reaction liquid was poured into 20 mL of ice water and stirred for 0.5 h, then extracted with ether (20 mL × 3), and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain a yellow oily liquid. The oil was placed in a refrigerator overnight, washed with ice water (20 mL × 3), and the solid was collected by filtration and dried to obtain 0.60 g of a viscous liquid with a yield of 69%.

[0094] Example 5

[0095] A method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, the synthetic route is:

[0096]

[0097] The specific steps are:

[0098] Accurately weigh 15.6 g (0.1 mol) of compound 1 into a 200 mL flask, add 78 g of methanol, start stirring, rotate at 500 rpm, and reflux at 50 ° C for 12 h. After the reaction is completed, cool to room temperature, remove the solvent by rotary evaporation at 30 ° C until solid precipitates, place at 0 ° C overnight to cool and crystallize, filter, and dry the obtained solid to obtain 15.5 g of compound 2, with a yield of 84%.

[0099] Accurately weigh 9.2 g (0.05 mol) of compound 2 into a 100 mL flask, add 46 g of anhydrous tetrahydrofuran, replace the air in the flask with nitrogen, seal it, place it in a -20 ° C low-temperature reactor, start stirring, and add 30 mL of lithium aluminum tetrahydride (2.5 M tetrahydrofuran solution, 0.075 mol) dropwise. After the addition is complete, react at room temperature for 2 h, then slowly add 20 mL of 5% sodium hydroxide solution at 0 ° C, continue stirring for 0.5 h, add 15 g of anhydrous magnesium sulfate, stir for 0.5 h, filter, collect the filtrate, and concentrate it by rotary evaporation to obtain 5.1 g of colorless oily liquid (compound 3) with a yield of 80%.

[0100] Accurately weigh 8.2 g (0.08 mol) of acetic anhydride into a 50 mL flask, place it in a -20 ° C low-temperature reactor, start stirring, slowly add 2.5 g (0.04 mol) of fuming nitric acid and 0.51 g (0.004 mol) of compound 3 in sequence, then let it react at room temperature for 1 h. The reaction liquid was poured into 40 mL of ice water and stirred for 0.5 h, and then extracted with ether (20 mL × 3). The organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain a yellow oily liquid, which was placed in a refrigerator overnight and washed with ice water (20 mL × 3). The solid was collected by filtration and dried to obtain 0.62 g of a viscous liquid with a yield of 71%.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, characterized in that The structure is as follows:

2. A method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate, characterized in that: The synthetic route of the bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate is: The preparation method comprises the following steps: (1) Compound 1 is subjected to esterification reaction to obtain compound 2; (2) Compound 2, a reducing agent, and a solvent are mixed to undergo a reduction reaction to obtain Compound 3; (3) Compound 3 is nitrated to obtain the product compound 4.

3. The method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate according to claim 2, characterized in that: The esterification reaction in step (1) is as follows: adding compound 1 to an alcohol reagent and reacting at 50-80° C. for 6-12 hours.

4. The method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate according to claim 3, characterized in that: The alcohol reagent is methanol; the mass ratio of the compound 1 to the alcohol reagent is 1:2-5.

5. The method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate according to any one of claims 2 to 4, characterized in that: The step (2) is specifically as follows: dissolving compound 2 in a solvent, cooling to -20 to 0°C, adding a reducing agent dropwise under the protection of an inert gas, and reacting at room temperature for 2 to 5 hours after the addition is complete.

6. The method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate according to claim 5, characterized in that: The solvent is tetrahydrofuran; the mass ratio of the compound 2 to the solvent is 1:5-20.

7. The method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate according to claim 6, characterized in that: The reducing agent is one of lithium aluminum hydride, lithium borohydride or diisobutylaluminum hydride, and the molar ratio of the compound 2 to the reducing agent is 1:1 to 1.

5.

8. The method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate according to claim 2, characterized in that: In the step (3), fuming nitric acid-acetic anhydride is used for nitration.

9. The method for preparing bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate according to claim 8, characterized in that: The molar ratio of the compound 3 to the fuming nitric acid is 1:2-10, the molar ratio of the fuming nitric acid to acetic anhydride is 1:2-5, the feeding temperature is -20-0°C, the reaction temperature is room temperature, and the reaction time is 1-5 hours.

10. Use of the bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate according to claim 1 in solid propellants, characterized in that: The bicyclo[1.1.1]pentane-1,3-dimethylene dinitrate is applied as a plasticizer to the formulation of HTPB-based solid propellants.

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