3-(3, 5-dinitrophenyl)-1, 2, 4-oxadiazole energetic compound and synthesis method thereof

Abstract

The invention discloses a synthesis method of a 3-(3, 5-dinitrophenyl)-1, 2, 4-oxadiazole energetic compound, which is structurally characterized in that a 3-(3, 5-dinitrophenyl)-1, 2, 4-oxadiazole ring is used as a basic skeleton, trifluoromethyl, trichloromethyl, amino, methyl azido and methyl hydroxyl are used as substituent groups, and the synthesis method belongs to the technical field of energetic materials. The 5-trifluoromethyl-3-(3, 5-dinitrophenyl)-1, 2, 4-oxadiazole and the 5-methyl azido-3-(3, 5-dinitrophenyl)-1, 2, 4-oxadiazole disclosed by the invention have the properties of low melting point and low sensitivity, and have an application prospect in the aspect of casting carrier explosives.

Description

Technical Field

[0001] The invention belongs to the technical field of energetic materials, and in particular relates to a method for synthesizing a class of 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole energetic compounds with low melting point and low sensitivity. Background Art

[0002] Cast explosives are the most widely used type of military mixed explosives, accounting for more than 90% of military mixed explosives, and occupy an important position in military mixed explosives. Cast explosives are mixed explosives formed by adding relatively insensitive explosives as carriers and high-energy explosives. They can be used for chamber charging of various shapes and have good comprehensive performance.

[0003] The traditional melt-cast carrier explosive trinitrotoluene (TNT) has many disadvantages, such as low energy, unsatisfactory mechanical properties, poor safety performance, and high toxicity. It has been gradually replaced by dinitroanisole (DNAN), but DNAN has problems such as low density and low energy level. For this reason, countries are constantly exploring and looking for new liquid carrier explosives with high energy and low sensitivity. At present, new melt-cast carrier explosives represented by 3,4-dinitropyrazole (DNP), 1,3,3-trinitroazetidine (TNAZ), 1-methyl-3,4,5-trinitropyrazole (MTNP), and 3,3'-bi-(1,2,4-oxadiazole)-5,5'-dimethylnitrate (BODN) have been developed. However, in general, the types of melt-cast carrier explosives are still very limited, and it is urgent to design and develop new melt-cast carrier explosives with excellent comprehensive performance.

[0004] A class of 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole energetic compounds, which structurally combine a nitrobenzene ring and an oxadiazole heterocycle, has a structural formula as shown in (I).

[0005]

[0006] R=CF 3 , CCl 3 NH 2 , CH 2 N 3 , CH 2 OH. Summary of the invention

[0007] The purpose of the present invention is to provide a class of 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole energetic compounds with low sensitivity and low melting point, the structural characteristics of which are 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole ring as the basic skeleton, methylazido and trifluoromethyl, trichloromethyl, amino, methylhydroxyl as substituents. The compounds have the characteristics of suitable melting point, simple synthesis, etc., and have application prospects in melt-cast carrier explosives.

[0008] The purpose of the present invention is to provide a method for synthesizing a class of 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole energetic compounds.

[0009] The synthesis method of the invention is simple, the reaction conditions are mild, the raw materials are easily available and the product yield is high.

[0010] The objective of the present invention is achieved through the following technical solutions:

[0011] The synthesis method of 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole of the present invention is achieved by the following steps: (1) adding 3,5-dinitrophenylamine oxime to a mixed solution of a certain amount of trifluoroacetic anhydride and trifluoroacetic acid at 0-40°C under mechanical stirring; (2) heating the system to 90°C and reflux for 3-16 hours; (3) cooling to room temperature, adding an appropriate amount of ice water, and precipitating a white solid; (4) stirring, filtering, and drying to obtain a 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

[0012] The synthesis method of 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole of the present invention is achieved by the following steps: (1) adding 3,5-dinitrophenylamine oxime to a certain amount of trichloroacetic anhydride at 0-40°C under mechanical stirring; (2) heating the system to 90°C and reflux for 0.5-3h; (3) cooling to room temperature, adding an appropriate amount of ice water, and precipitating a white solid; (4) stirring, filtering, and drying to obtain a 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

[0013] The synthesis method of 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole of the present invention is achieved by the following steps: (1) taking a certain amount of NaOH solid and adding it into a three-necked flask, and then taking an excess amount of ammonia water into a constant pressure dropping funnel to prepare ammonia gas; (2) taking 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole and dissolving it in a certain amount of methanol, placing it in an ice bath at 0°C and stirring; (3) introducing an excess amount of ammonia gas in a slow bubbling manner, and the white solid gradually dissolves, and the bubbling reaction is continued for 3 to 8 hours; (4) after the reaction is completed, the temperature is raised to room temperature; (5) filtering and washing with a small amount of methanol to obtain a 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

[0014] The synthesis method of 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole of the present invention is achieved by the following steps: (1) suspending 3,5-dinitrophenylamine oxime in a certain amount of toluene at 0-40° C. and under mechanical stirring; (2) adding dropwise a toluene solution of 2-3 times the equivalent of chloroacetyl chloride; (3) heating to 110° C. and reflux for 4-6 hours; (4) cooling to room temperature, and drying the solvent to obtain a white intermediate; (5) dissolving the white intermediate in a certain amount of acetonitrile, and adding 1-2 times the equivalent of NaN 3 , stirring at 55°C for 8 to 12 hours; (6) cooling to room temperature, pouring the solution onto ice water and stirring for 30 minutes; (7) filtering and drying to obtain 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

[0015] The synthesis method of 5-methylhydroxy-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole of the present invention is achieved by the following steps: (1) dissolving 3,5-dinitrophenylamine oxime in a certain amount of acetonitrile at 0-40° C. and under mechanical stirring, adding 1-2 times the equivalent of K 2 CO 3 ; (2) add 1 to 1.5 times the equivalent of acetoxyacetyl chloride in acetonitrile dropwise; (3) heat to 83°C and reflux for 3 to 6 hours; (4) cool to room temperature and spin dry the solvent; (5) add a certain amount of water to dilute the solid, then extract with a certain amount of ethyl acetate and collect the organic phase; (6) use anhydrous MgSO 4 After drying, the organic phase was spin-dried to obtain a purple-black intermediate; (7) the purple-black intermediate was dissolved in a certain amount of methanol solvent; (8) 0.1 to 1 equivalent of K 2 CO 3 , raise the temperature to 65°C and reflux for 2 to 4 hours; (9) spin dry the solvent, add a small amount of water to wash the solid, and dry it to obtain 5-methylhydroxy-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

[0016] A type of 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole energetic compound sample obtained by the present invention has its structure confirmed by elemental analysis, infrared spectrum, nuclear magnetic resonance carbon spectrum, hydrogen spectrum and X-ray single crystal diffraction, and its thermal decomposition characteristics, mechanical impact sensitivity, friction sensitivity, etc. are tested to evaluate its detonation performance, and its application in the field of energetic materials is disclosed.

[0017] Beneficial Effects

[0018] 1. The 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole energetic compound described in the present invention has a stable structure and has good thermal stability and low sensitivity.

[0019] 2. The synthesis method of the 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole energetic compound described in the present invention is simple, the reaction conditions are mild, the raw materials are easily available, and the product yield is high.

[0020] 3. The 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole and 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole described in the present invention can be used in the field of high-energy low-sensitivity melt-cast carrier explosives. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The molecular structure diagram of 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0022] Figure 2 It is the carbon NMR spectrum of 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0023] Figure 3 is the hydrogen nuclear magnetic resonance spectrum of 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0024] Figure 4 The molecular structure diagram of 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0025] Figure 5 It is the carbon NMR spectrum of 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0026] Figure 6 is the hydrogen nuclear magnetic resonance spectrum of 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0027] Figure 7 The molecular structure diagram of 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0028] Figure 8 is the carbon NMR spectrum of 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0029] Fig. 9 is the hydrogen nuclear magnetic resonance spectrum of 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0030] Fig.10 The molecular structure diagram of 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0031] Fig.11 It is the carbon NMR spectrum of 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0032] Fig.12 is the hydrogen nuclear magnetic resonance spectrum of 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0033] Fig.13 The molecular structure diagram of 5-methylhydroxy-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0034] Fig.14 It is the carbon NMR spectrum of 5-methylhydroxy-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole;

[0035] Fig.15 is the hydrogen nuclear magnetic resonance spectrum of 5-methylhydroxy-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole; DETAILED DESCRIPTION

[0036] The present invention is implemented through the following embodiments, but the conditions and results described in the implementation do not limit the content and rights of the invention.

[0037] Example 1 Synthesis of 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole

[0038] The specific synthesis method of 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole is as follows: (1) taking 0.50 g (2.2 mmol) of dinitrophenylamine oxime, adding it to a mixed solution of 5 mL (35.9 mmol) of trifluoroacetic anhydride and 5 mL (61.7 mmol) of trifluoroacetic acid under stirring conditions; (2) heating the system to 90° C. and refluxing for 6 h; (3) cooling to room temperature, adding 20 mL of ice water, and precipitating a white solid; (4) stirring for 30 min, filtering, and drying to obtain 0.54 g of white powder, with a yield of 88.7%.

[0039] DSC (10℃·min -1 ): 97°C (mp); 13 C NMR (101 MHz, DMSO-d 6 ,25℃)δ:166.55,166.50,149.36,127.67,122.30,117.41,114.70. 1 H NMR (400MHz, DMSO) δ9.12 (1H), 9.09 (2H); IR (KBr, ν / cm -1):3093(m),1555(s),1544(s),1346(s),1185(s),1144(s),1080(w),920(m),765(m).

[0040] Example 2 Synthesis of 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole

[0041] The specific synthesis method of 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole is as follows: (1) 0.50 g (2.2 mmol) of dinitrophenylamine oxime is added to 5 mL (8.16 g, 26.4 mmol) of trichloroacetic anhydride under stirring; (2) the system is heated to 90° C. and refluxed for 1 h; (3) the system is cooled to room temperature, 20 mL of ice water is added, and a white solid is precipitated; (4) the mixture is stirred for 30 min and filtered, and after drying, 0.65 g of a white powder is obtained, with a yield of 83.6%.

[0042] DSC (10℃·min -1 ): 130℃(mp); 13 C NMR (101 MHz, DMSO-d 6 ,25℃)δ:175.17,166.68,149.22,128.11,127.75,122.14,82.73. 1 H NMR(400MHz,DMSO)δ9.06(1H),9.02(2H).IR(KBr,ν / cm -1 ):3084(m),1555(m),1342(s),1168(w),1082(w),919(m),826(m),722(m).

[0043] Example 3 Synthesis of 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole

[0044] The specific synthesis method of 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole is as follows: (1) 40.00 g of solid NaOH is added to a three-necked flask, and then 40 mL of ammonia water is added to a constant pressure dropping funnel, a safety bottle, a drying bottle, a reaction bottle and an exhaust gas treatment device are connected, the opening of the constant pressure dropping funnel is controlled, and ammonia water is slowly dripped into NaOH to prepare ammonia gas; (2) 0.50 g (1.4 mmol) of 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole is added to a reaction bottle, 30 mL of methanol is added, and the reaction bottle is placed in an ice bath at 0°C and stirred; (3) Excess ammonia gas is introduced in a slow bubbling manner, and the white solid gradually dissolves, and the bubbling reaction is continued for 3 hours; (4) The reaction is heated to room temperature to form a precipitate; (5) Filter and wash with a small amount of methanol to obtain 0.26 g of a khaki solid with a yield of 73.3%.

[0045] DSC (10℃·min -1 ): 168°C (mp); 13 C NMR (101 MHz, DMSO-d 6 ,25℃)δ:173.20,165.41,149.08,130.73,126.73,120.73. 1 H NMR(400MHz,DMSO)δ9.03(1H),8.97(2H),8.39(NH 2 ,2H)IR(KBr,ν / cm -1 ):3421(m),1577(m),1340(s),1180(w),1081(w),910(m),768(m),732(m).

[0046] Example 4 Synthesis of 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole

[0047] The specific synthesis method of 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole is as follows: (1) 1.00 g (4.4 mmol) of dinitrophenylamine oxime is suspended in 40 mL of toluene; (2) 1.12 g (8.8 mmol, 2 eq.) of chloroacetyl chloride in 10 mL of toluene solution is added dropwise; (3) the temperature is raised to 110° C. and refluxed for 4 h; (4) the temperature is cooled to room temperature, and the solvent is dried by rotary evaporation to obtain a white intermediate; (5) the white intermediate is dissolved in 30 mL of acetonitrile, and 0.20 g of NaN is added. 3 , stirring at 55°C for 10 h; (6) cooling to room temperature, placing the solution on 20.00 g of ice, and stirring for 20 min; (7) filtering, drying, and obtaining 0.96 g of beige solid, with a yield of 75.0%.

[0048] DSC (10℃·min-1 ): 81.1℃(mp); 13 C NMR (101 MHz, DMSO-d 6 ,25℃)δ:177.48,165.81,149.29,128.94,127.36,124.61,45.17. 1 H NMR(400MHz,DMSO)δ9.02(3H),5.09(CH 2 ,2H)IR(KBr,ν / cm -1 ):3102(m),2114(s),1541(s),1351(s),1082(w),920(m).

[0049] Example 5 Synthesis of 5-methylhydroxy-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole

[0050] The specific synthesis method of 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole is as follows: (1) 1.00 g (4.4 mmol) of dinitrophenylamine oxime was dissolved in 50 mL of acetonitrile, and 0.62 g (1 eq.) of K 2 CO 3 ; (2) Add 0.65 g of acetoxyacetyl chloride in 20 mL of acetonitrile solution dropwise to the dinitrobenzene amidoxime solution; (3) Heat to 83 °C and reflux for 3 h; (4) Cool to room temperature and spin dry the solvent; (5) Add 20 mL of water to dilute the solid, extract with 60 mL of ethyl acetate, and collect the organic phase; (6) Use anhydrous MgSO 4 After drying, the organic phase was spin-dried to obtain a purple-black intermediate; (7) the purple-black intermediate was dissolved in 40 mL of methanol; (8) 0.10 g of K 2 CO 3 , raise the temperature to 65°C and reflux for 2h; (9) spin dry the solvent, add a small amount of water to wash the solid, and after drying, obtain 0.71g of brown-black solid, with a yield of 60.3%.

[0051] DSC (10℃·min -1 ): 150℃(mp); 13 C NMR (101 MHz, DMSO-d 6 ,25℃)δ:181.41,165.55,149.27,129.28,127.29,121.44,55.67. 1 H NMR(400MHz,DMSO)δ9.01(3H),6.21(OH,1H),4.90(CH 2 ,2H).IR(KBr,ν / cm -1):3299(w),3091(w),1559(m),1340(m),1204(w),1084(m),917(m),783(w).

[0052] Table 1 Physical, chemical and detonation properties of energetic compounds of 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole

[0053]

[0054] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A class of 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole energetic compounds with low sensitivity, whose structural characteristics are that 3-(3,5-dinitrophenyl)-1,2,4-oxadiazole ring is used as the basic skeleton, and trifluoromethyl, trichloromethyl, amino, methylazido, and methylhydroxyl are substituents, and its structural formula is as follows.

2. The method for synthesizing 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole according to claim 1, characterized in that: (1) Add 3,5-dinitrophenylamine oxime to a certain amount of a mixed solution of trifluoroacetic anhydride and trifluoroacetic acid at 0-40°C with mechanical stirring; (2) Heat the system to 90°C and reflux for 3-16 hours; (3) Cool to room temperature, add an appropriate amount of ice water, and precipitate a white solid; (4) Stir and filter, and dry to obtain a 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

3. The method for synthesizing 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole according to claim 2, characterized in that: In step (1), the volume ratio of trifluoroacetic acid to trifluoroacetic anhydride is 0.1:1 to 1:1, and the molar ratio of trifluoroacetic anhydride to 3,5-dinitrobenzene amidoxime is 1:1 to 10:

1.

4. The method for synthesizing 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole according to claim 1, characterized in that: (1) adding 3,5-dinitrophenylamine oxime to a certain amount of trichloroacetic anhydride at 0-40°C with mechanical stirring; (2) raising the temperature of the system to 90°C and reflux for 0.5-3h; (3) cooling to room temperature, adding an appropriate amount of ice water, and precipitating a white solid; (4) stirring, filtering, and drying to obtain 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

5. The method for synthesizing 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole according to claim 1, characterized in that: (1) Take a certain amount of NaOH solid and add it to a three-necked flask, then take excess ammonia water into a constant pressure dropping funnel to prepare ammonia gas; (2) Take 5-trichloromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole and dissolve it in a certain amount of methanol, place it in an ice bath at 0°C and stir; (3) Slowly bubbling excess ammonia gas, the white solid gradually dissolves, and the bubbling reaction is continued for 3 to 8 hours; (4) After the reaction is completed, the reaction mixture is heated to room temperature; (5) Filter and wash with a small amount of methanol to obtain 5-amino-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

6. The method for synthesizing 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole according to claim 1, characterized in that: (1) Suspend 3,5-dinitrobenzeneamine oxime in a certain amount of toluene at 0-40°C with mechanical stirring; (2) Add 2-3 equivalents of chloroacetyl chloride in toluene solution dropwise; (3) Heat to 110°C and reflux for 4-6 hours; (4) Cool to room temperature and spin dry the solvent to obtain a white intermediate; (5) Dissolve the white intermediate in a certain amount of acetonitrile, add 1-2 equivalents of NaN3, and stir at 55°C for 8-12 hours; (6) Cool to room temperature, pour the solution on ice water, and stir for 30 minutes; (7) Filter and dry to obtain 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

7. The method for synthesizing 5-methylhydroxy-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole according to claim 1, characterized in that: (1) Dissolve 3,5-dinitrobenzeneamine in a certain amount of acetonitrile at 0-40°C with mechanical stirring, and add 1-2 equivalents of K2CO3; (2) Add 1-1.5 equivalents of acetoxyacetyl chloride in acetonitrile dropwise; (3) Heat to 83°C and reflux for 3-6 hours; (4) Cool to room temperature and spin dry the solvent; (5) Add a certain amount of water to dilute the solid, extract with a certain amount of ethyl acetate, and collect the organic phase; (6) Dry the organic phase with anhydrous MgSO4 and spin dry to obtain a purple-black intermediate; (7) Dissolve the purple-black intermediate in a certain amount of methanol solvent; (8) Add 0.1-1 equivalents of K2CO3, heat to 65°C and reflux for 2-4 hours; (9) Spin dry the solvent, add a small amount of water to wash the solid, and dry to obtain 5-methylhydroxy-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole product.

8. Use of 5-trifluoromethyl-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole and 5-methylazido-3-(3,5-dinitrophenyl)-1,2,4-oxadiazole according to claim 1 in the field of melt-cast carrier explosives.

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