Liquid stabilizing agent for nitrate ester compound and preparation method of liquid stabilizing agent

Abstract

The preparation method comprises the following steps: under stirring at 20-30 DEG C, adding a phenol derivative, glycidyl ether and an alkaline substance into a water-containing organic solvent, uniformly stirring and mixing, heating to 40-80 DEG C in an oil bath to reflux ethanol, stirring and reacting for 4-40 hours, cooling, adding an extraction solvent, filtering, washing, and drying to obtain the liquid stabilizing agent for the nitrate compound. And washing the extract with a 1M aqueous sodium hydroxide solution for three times, carrying out liquid separation, removing the water layer, collecting an organic solution layer, washing the organic solution layer with a saturated sodium chloride solution for three times, and carrying out rotary evaporation to remove ethyl acetate so as to obtain a product, namely the liquid stabilizer. The molecular structure of the liquid stabilizing agent contains a large number of ether bond structures, so that the liquid stabilizing agent becomes an oxygen-containing stabilizing agent, and after the liquid stabilizing agent is compounded with a nitrate compound, the rapid combustion performance of the nitrate compound is slightly influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of organic stabilizers, and in particular to a compound that stabilizes nitrate ester compounds and energetic materials formed by compounding various nitrate ester compounds, and a method for synthesizing the compound. Background Art

[0002] Nitrate compounds and complexes composed of various nitrate compounds are the main components of energetic materials. However, nitrate compounds will absorb trace amounts of water during long-term storage to undergo hydrolysis reactions to generate acids, or generate nitroxide free radicals due to thermal decomposition reactions. Acids and nitroxide free radicals will catalyze and accelerate the decomposition of nitrates to generate more acids and nitroxide free radicals. Repeated cycles of self-catalytic decomposition cause the performance of energetic materials to deteriorate and even generate heat, combustion, and explosion. Therefore, appropriate stabilizers (called stabilizers) must be added for stability treatment. The stabilizers currently added are mainly aniline derivatives, which can absorb the acid, nitrogen oxides and free radicals released by the decomposition of nitrate esters, thereby inhibiting the autocatalytic decomposition reaction of nitrate esters. They include N-methyl-p-nitroaniline (MNA), diphenylamine (DPA), 2-nitrodiphenylamine (2-NDPA), N,N-diphenylurea (AK-I), N-methyl-N'-diphenylurea (AK-II), N,N'-diethyl-N,N'-diphenylurea (C1), N,N'-dimethyl-N,N'-diphenylurea (C2), etc.

[0003] However, the initial nitrosation rate of aniline stabilizers is slow, and they have little stabilizing effect on some nitrate compounds, and they are often not used alone for some special nitrate compounds. In addition, nitrous acid, the intermediate product of nitrate decomposition, and amine compounds can form stable nitrosamine derivatives, which are considered to have strong carcinogenic effects. The list of carcinogens released by the World Health Organization's International Agency for Research on Cancer lists a number of nitrosamine derivatives with different structures, which makes this type of stabilizer cause additional occupational safety risks during the processing, storage and transportation of energetic materials. Therefore, designing and synthesizing new stabilizers that can meet the stability requirements of energetic materials and are green and non-toxic is of great significance to the performance optimization and improvement of energetic materials using nitrate compounds.

[0004] Based on the understanding of the decomposition and stabilization mechanism of nitrate compounds, studies have confirmed that phenol derivatives with specific structures also show good stabilization effects on nitrate compounds and may be used as stabilizers for energetic materials containing nitrate compounds. For example, Krumlinde et al. reported that bis-(2,6-dimethoxyphenol) triglycerol ether has a good stabilization effect on nitrocellulose (Patrik Krumlinde et al., Propellants Explos. Pyrotech. 2017, 42, 78); Wang Xijie et al. publicly reported the synthesis of the compound (Wang Xijie et al., Applied Chemical Industry, 2019, 48 (Supplement 2): 249); Chinese invention patents CN107032964A, CN107011128A and CN106946664A disclose the synthesis method of the compound and its application as a stabilizer for nitrate compounds. However, this phenol derivative is solid at room temperature and needs to be dissolved in a specific solvent before it can be used in the preparation of energetic materials. In addition, its stability has not been widely recognized, and large-scale production and application have not been achieved. Summary of the invention

[0005] In view of the problems that existing aniline derivative stabilizers have poor effects and are prone to produce toxic substances, and that phenol derivatives such as bis-(2,6-dimethoxyphenol) triglyceride are solid and not conducive to large-scale application, the present invention provides a phenol derivative that is liquid at room temperature and has a new chemical structure and is used as a stabilizer for energetic materials containing nitrate ester compounds.

[0006] In a first aspect, the present invention provides a liquid stabilizer for nitrate ester compounds, having the following structure:

[0007]

[0008] Where x is a repeating unit, 1≤x≤6; n is OR 3 The number of, 1≤n≤5; R 1 is an alkane residue, R 2 and R 3 are independently selected from a hydrogen atom (H) or a linear alkyl group.

[0009] Preferably, when x=3, n=2, OR 3 Located at position 2 and 6, or OR 3 Located at positions 3 and 5, or OR 3 Located at positions 2 and 4; R 1 is a trimethylolpropane residue, R 2 =H, R 3 =CH 3 .

[0010] Preferably, when x=3, n=3, OR3 Located at positions 2, 4 and 6; R 1 is a trimethylolpropane residue, R 2 =H, R 3 =CH 3 .

[0011] Preferably, when x=4, n=2, OR 3 Located at position 2 and 6, or OR 3 Located at positions 3 and 5, or OR 3 Located at positions 2 and 4; R 1 is the pentaerythritol residue, R 2 =H, R 3 =CH 3 .

[0012] Preferably, when x=4, n=3, OR 3 Located at positions 2, 4 and 6; R 1 is the pentaerythritol residue, R 2 =H, R 3 =CH 3 .

[0013] Preferably, when x=3, n=2, OR 3 Located at positions 2 and 6; R 1 is a trimethylolpropane residue, R 2 =CH 3 , R 3 =CH 3 .

[0014] Preferably, when x=4, n=2, OR 3 Located at positions 2 and 6; R 1 is the pentaerythritol residue, R 2 =CH 3 , R 3 =CH 3 .

[0015] Preferably, when x=6, n=2, OR 3 Located at positions 2 and 6; R 1 is a dipentaerythritol residue, R 2 =CH 3 or H, R 3 =CH 3 .

[0016] In a second aspect, the present invention provides a method for synthesizing the liquid stabilizer according to the first aspect, comprising:

[0017] The step of reacting a phenol derivative and a glycidyl ether in an aqueous organic solvent under alkaline conditions to prepare a target product, a liquid stabilizer,

[0018]

[0019] Preferably, phenol derivatives include but are not limited to phenol (n=0), alkoxyphenol (1≤n≤5) and alkylphenol, wherein alkoxyphenol and alkylphenol are more preferred. Alkoxyphenol includes but is not limited to 2,4-dimethoxyphenol, 2,6-dimethoxyphenol, 3,5-dimethoxyphenol, 2,4,6-trimethoxyphenol, 2,4-diethoxyphenol, 2,6-diethoxyphenol, 3,5-diethoxyphenol, 2,4,6-triethoxyphenol, 2,4-dipropoxyphenol, 2,6-dipropoxyphenol, 3,5-dipropoxyphenol, 2,4,6-tripropoxyphenol. Oxyphenol, 2,4-diisopropoxyphenol, 2,6-diisopropoxyphenol, 3,5-diisopropoxyphenol, 2,4,6-triisopropoxyphenol, 2,4-di-tert-butoxyphenol, 2,6-di-tert-butoxyphenol, 3,5-di-tert-butoxyphenol, 2,4,6-tri-tert-butoxyphenol; alkylphenols include but are not limited to o-methylphenol, m-methylphenol, p-methylphenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-propylphenol, m-propylphenol, p-propylphenol, o-isopropylphenol, m-isopropylphenol, p-isopropylphenol, m-tert-butylphenol, p-tert-butylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 3,5-dimethylphenol, 2,4,6-trimethylphenol, 2,4-diethylphenol, 2,6-diethylphenol, 3,5-diethylphenol, 2,4,6-trimethylphenol One or more of ethylphenol, 2,4-dipropylphenol, 2,6-dipropylphenol, 3,5-dipropylphenol, 2,4,6-tripropylphenol, 2,4-diisopropylphenol, 2,6-diisopropylphenol, 3,5-diisopropylphenol, 2,4,6-triisopropylphenol, 2,4-di-tert-butylphenol, 2,6-di-tert-butylphenol, 3,5-di-tert-butylphenol and 2,4,6-tri-tert-butylphenol.

[0020] Preferably, the glycidyl ether includes, but is not limited to, one or more of ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, resorcinol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol A propoxylated diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, castor oil triglycidyl ether, pentaerythritol tetraglycidyl ether, dipentaerythritol hexaglycidyl ether, and sorbitol hexaglycidyl ether.

[0021] Preferably, the reaction between the glycidyl ether and the phenol derivative is carried out under alkaline conditions, and the alkaline substance used includes but is not limited to a combination of one or more of lithium hydroxide, potassium hydroxide, potassium hydride, sodium hydroxide, sodium hydride, potassium carbonate, sodium carbonate, potassium methoxide, sodium methoxide, butyl lithium, lithium diisopropylamide, benzyl lithium, sodium ethoxide, potassium ethoxide, sodium tert-butoxide, potassium amide, and sodium amide.

[0022] Preferably, the organic solvent in the aqueous organic solvent includes, but is not limited to, a combination of one or more of methanol, ethanol, propanol, n-butanol, tert-butanol, ethylene glycol, propylene glycol, ethyl ether, methyl ethyl ether, acetone, butanone, dimethylformamide, dimethyl sulfoxide, acetonitrile, and dioxane, and the volume ratio of the organic solvent to water in the aqueous organic solvent is 1:1.

[0023] Preferably, the reaction temperature is between room temperature and the boiling point of the solvent, preferably 40-80°C, and the reaction time varies from several minutes to several tens of hours, preferably 4-40 hours.

[0024] Preferably, after the reaction is completed, the mixture is separated and purified by extraction. According to different solvent systems, available extraction solvents include but are not limited to a combination of one or more of methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, isoamyl formate, benzyl formate, methyl acetate, ethyl acetate, ethyl acetoacetate, n-propyl acetate, n-butyl acetate, sec-butyl acetate, amyl acetate, isoamyl acetate, methyl amyl acetate, methyl propionate, n-butyl propionate, amyl propionate, methyl butyrate, ethyl butyrate, n-butyl butyrate, diethyl oxalate, dibutyl oxalate, etc.

[0025] In a third aspect, the present invention provides a use of the liquid stabilizer described in the first aspect in a propellant.

[0026] Compared with the prior art, the invention has the following beneficial effects: the liquid stabilizer for nitrate ester compounds is liquid at room temperature and is easily mixed and dissolved with nitrate ester compounds to form a homogeneous system. The oxygen-containing, liquid phenol derivatives do not produce carcinogenic nitrosamines after being compounded with nitrate ester compounds, and thus exhibit the characteristics of low toxicity, soluble (soluble in conventional solvents) or liquid, and not interfering with the solidification of nitrate ester compounds. The liquid stabilizer for nitrate ester compounds contains a large number of ether bond structures in its molecular structure, thus becoming an oxygen-containing stabilizer, which has less influence on the rapid combustion performance of nitrate ester compounds after being compounded with nitrate ester compounds; a new path has been opened up for the research and development of energetic materials such as propellants based on nitrate ester compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1This is the infrared spectrum of the product 01 obtained in Example 1.

[0028] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the product 01 obtained in Example 1.

[0029] Figure 3 This is the ultraviolet spectrum analysis chart of the product 01 obtained in Example 1.

[0030] Figure 4 This is the liquid chromatography analysis chart of the product 01 obtained in Example 1.

[0031] Figure 5 This is the effect of different reaction media on product yield in Example 7.

[0032] Figure 6 The color changes of different samples in Application Example 2 before (a) and after (b) heating. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with embodiments, but the description of the embodiments does not impose any limitation on the protection scope of the present invention.

[0034] Example 1

[0035] In a 250mL flask equipped with ancillary equipment such as a reflux condenser, a stirrer, and a thermometer, 30g of trimethylolpropane triglycidyl ether, 46g of 2,6-dimethoxyphenol, 5g of potassium carbonate, and an aqueous organic solvent (100mL of organic solvent ethanol and 100mL of water) were added at room temperature, and the mixture was stirred and mixed evenly. The temperature was gradually increased in an oil bath to reflux the ethanol, and the stirring reaction was maintained for 20 hours. After cooling, 100mL of ethyl acetate was added, and the mixture was allowed to stand for stratification after vigorous stirring. The upper extract was collected by separation, and the lower solution was extracted twice with 100mL of ethyl acetate each time. The extracts were combined, and 50mL of 1M sodium hydroxide aqueous solution was added each time to wash three times. The organic solution layer was separated and the water layer was discarded, and the organic solution layer was collected. The organic solution layer was washed three times with 150mL of saturated sodium chloride solution, and the ethyl acetate was removed by rotary evaporation to obtain about 60g of product 01.

[0036] The product 01 was analyzed by infrared spectrum, nuclear magnetic resonance hydrogen spectrum, ultraviolet spectrum and liquid chromatography respectively, and the results were as follows: Figures 1 to 4 shown. Figure 1 and Figure 2 The chemical structure of product 01 was revealed. Figure 3 and Figure 4 It was proved that the purity of product 01 reached 98%.

[0037] Example 2

[0038] Similar to Example 1, but replacing 2,6-dimethoxyphenol with 3,5-trimethoxyphenol, about 58 g of product 02 was obtained.

[0039] Example 3

[0040] Similar to Example 1, but replacing 2,6-dimethoxyphenol with 2,4-trimethoxyphenol, about 50 g of product 03 was obtained.

[0041] Example 4

[0042] Similar to Example 1, but 30 g of trimethylolpropane triglycidyl ether was replaced with 36 g of pentaerythritol tetraglycidyl ether, and 62 g of 2,6-dimethoxyphenol was added, methanol was used as solvent, and the mixture was stirred and refluxed at 60° C. for 40 hours, and extracted with butyl acetate to finally obtain about 80 g of product 05.

[0043] Example 5

[0044] Similar to Example 1, except that 30 g of trimethylolpropane triglycidyl ether was replaced with 60 g of dipentaerythritol hexaglycidyl ether, and 92 g of 2,6-dimethoxyphenol was added. Dimethylformamide was used as solvent, the reaction was stirred at 80° C. for 8 hours, and extracted with butyl acetate to finally obtain about 100 g of product 11.

[0045] Example 6

[0046] Based on Example 5, product 11 was reacted with iodomethane under reflux in a methanol / sodium methoxide solution, then washed thoroughly with water and dried to obtain product 12.

[0047] Example 7 Effect of reaction medium on product yield

[0048] The other processes are the same as in Example 1, except that the aqueous organic solvent is changed to acetonitrile, methanol, water, ethanol and other solvents and their mixed solvents. This experiment uses different reaction media to prepare stabilizers and tests the synthetic yield of stabilizers in solvents. The results are as follows Figure 5 shown.

[0049] Depend on Figure 5 It can be seen that due to the low solubility of acetonitrile in KOH, it is difficult to provide a sufficient alkaline environment, which is not conducive to the removal of small molecule HCl, and the synthesis yield is low. Methanol and ethanol also have similar situations, and small molecule alcohols are also partially involved in the side reaction, the product is difficult to purify, and the overall yield is low.

[0050] After analysis, it is found that using a mixed solvent of ethanol and water as the reaction medium can improve the solubility of KOH, reduce the reaction cost, and improve the safety of the medium. Figure 5As shown, when an ethanol-water mixed solvent is used as the reaction medium, the synthesis yield is significantly improved compared with a single reaction medium, and when the ratio of ethanol to water is 1:1, the yield reaches the highest.

[0051] Application Example 1 Compatibility of Stabilizer and Propellant Components

[0052] The compatibility of product 01 in Example 1 and double-base propellant was tested according to GJB772A-97 method 502.1. The results are shown in Table 1.

[0053] Table 1 Compatibility of stabilizer (product 01) with double-base propellant

[0054]

[0055] a.ΔT p ≤2.0℃, ΔE / E≤20%, good compatibility, Grade I;

[0056] b.ΔT p ≤2.0℃, ΔE / E>20%, good compatibility, grade 11;

[0057] c.ΔT p >2.0℃, ΔE / E≤20%, poor compatibility, 111 grade:

[0058] d.ΔT p >2.0℃,ΔE / E>20%, poor compatibility, Grade IV.

[0059] Application Example 2: Stability Test

[0060] (1) Color judgment

[0061] The product 01 of Example 1 and diphenylamine were mixed with nitrocellulose at a mass ratio of 1% respectively, and dried to obtain samples 1 and 2. The pictures of sample 1 and sample 2 before heating are as follows Figure 6 As shown in a, sample 1 and sample 2 were placed in an oven at 80°C for 14 days. After 14 days, the two samples were compared. Figure 6 As shown in b, the results show that product 01 has a stable effect comparable to that of diphenylamine.

[0062] (2) Vienna and methyl violet tests

[0063] The stability of the product 01 in Example 1 and the double-base propellant were judged according to the GJB770B method 503.1 and GJB770B method 503.3 Vienna and methyl violet tests, respectively. The results are shown in Table 2.

[0064] Table 2 Test results of samples Violet and methyl violet

[0065]

[0066] Note: The passing criteria for the 106.5℃ Vienna test are 7-7h for the common method and 70-70h for the repeated method; the passing criteria for the 120℃ methyl violet test are color change time>60min and non-explosion time>5h.

[0067] As can be seen from Table 2, product 01 passed both Vienna and methyl violet tests and had stability comparable to that of existing stabilizers.

[0068] Application Example 3 Effect of Stabilizer on Propellant Combustion Performance

[0069] The propellant was prepared according to the formula in Table 3, and the combustion performance of the prepared propellant was tested. The results are shown in Table 4.

[0070] Table 3 Double base propellant formula

[0071]

[0072] Table 4 Combustion performance and explosion heat test results

[0073]

[0074] As shown in Table 4, 0.7% of product 01 was used to replace C 2 After that, the propellant explosion heat increased by 14KJ / Kg; 1.2% of product 01 was used to replace C 2 After that, the explosion heat of the propellant increased by 34KJ / Kg; the explosion heat coefficient of product 01 was preliminarily determined to be about -16.6KJ / Kg, C 2 The explosion heat coefficient is about -22.5KJ / Kg.

[0075] Use product 01 to replace part C 2 After that, the explosion heat of the propellant increases, which is mainly because the stabilizer prepared by the present invention contains oxygen in its structure.

[0076] Molecular simulation calculations show that the oxygen content in the product 01 molecule reaches 30.3%, while C 2 The stabilizer molecule does not contain oxygen, therefore, the stabilizer of the present invention is beneficial to improving the energy characteristics of the propellant, which is consistent with the actual measurement results.

[0077] Application Example 4: 7-day accelerated aging test of stabilizer

[0078] According to GJB770B-2005 "Test Methods for Explosive Powders Method 506.1 Estimation of Safe Storage Life Thermal Accelerated Aging Method", the accelerated aging test was carried out at 1%C 2The sample prepared by dissolving 70% nitrocellulose with a nitrogen content of 12.6% and 29% nitroglycerin in a mixed solvent of ethanol and acetone, casting into a thin sheet and drying it was used as a reference sample. The sample prepared by dissolving 1% of the synthetic stabilizer (product 01), 70% nitrocellulose with a nitrogen content of 12.6% and 29% nitroglycerin in a mixed solvent of ethanol and acetone, casting into a thin sheet and drying it was used as a test sample. The test results are shown in Table 5.

[0079] Table 5 Effective stabilizer content at 70℃ accelerated aging

[0080]

[0081] Based on the effective stabilizer content, the estimated safe storage life of product 01 in double-base propellant is greater than C 2 Safe storage life of stabilizer.

[0082] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A liquid stabilizer for nitrate ester compounds, characterized in that: It has the following structure: Wherein, x is a repeating unit, 1≤x≤6; n is the number of OR3, 1≤n≤5; R1 is an alkane residue, and R2 and R3 are independently selected from a hydrogen atom (H) or a straight-chain alkyl group.

2. The liquid stabilizer according to claim 1, characterized in that When x=3, n=2, OR3 is located at the 2-position and the 6-position, or OR3 is located at the 3-position and the 5-position, or OR3 is located at the 2-position and the 4-position; R1 is a trimethylolpropane residue, R2=H, R3=CH3.

3. The liquid stabilizer according to claim 1, characterized in that When x=3, n=3, OR3 is located at the 2-, 4- and 6-positions; R1 is a trimethylolpropane residue, R2=H, and R3=CH3.

4. The liquid stabilizer according to claim 1, characterized in that: When x=4, n=2, OR3 is located at the 2-position and the 6-position, or OR3 is located at the 3-position and the 5-position, or OR3 is located at the 2-position and the 4-position; R1 is a pentaerythritol residue, R2=H, R3=CH3.

5. The liquid stabilizer according to claim 1, characterized in that: When x=4 and n=3, OR3 is located at the 2-, 4- and 6-positions; R1 is a pentaerythritol residue, R2=H, and R3=CH3.

6. The liquid stabilizer according to claim 1, characterized in that: When x=3, n=2, OR3 is located at the 2-position and the 6-position; R1 is a trimethylolpropane residue, R2=CH3, R3=CH3.

7. The liquid stabilizer according to claim 1, characterized in that When x=4, n=2, OR3 is located at the 2-position and the 6-position; R1 is a pentaerythritol residue, R2=CH3, and R3=CH3.

8. The liquid stabilizer according to claim 1, characterized in that: When x=6 and n=2, OR3 is located at the 2-position and the 6-position; R1 is a dipentaerythritol residue, R2=CH3 or H, and R3=CH3.

9. A method for synthesizing a liquid stabilizer as claimed in any one of claims 1 to 8, characterized in that: include: The step of reacting a phenol derivative and a glycidyl ether in an aqueous organic solvent under alkaline conditions to prepare a target product, a liquid stabilizer, 10. Use of the liquid stabilizer according to any one of claims 1 to 8 in a propellant.

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