Preparation method of carboxyl-terminated dinitramine compound

Abstract

The invention discloses a preparation method of a carboxyl-terminated dinitramine compound, which takes N, N '-bis (2-cyanoethyl) alkyl dinitramine as a raw material, and comprises the following steps: adding N, N'-bis (2-cyanoethyl) alkyl dinitramine and alkali metal iodide into a 5-25% aqueous alkali solution, heating until boiling, and carrying out hydrolysis reaction; and after the reaction is ended, cooling the reaction liquid in an ice-water bath, adjusting the pH value to 4-5 by using 5-25% dilute acid, separating out a large amount of solid, filtering to obtain a crude product, and recrystallizing twice by using water to obtain the N, N '-dinitrodiaza alkyl diacid. The method can solve the problems of long hydrolysis reaction time, low reaction efficiency, large waste acid amount and the like in the preparation process of the N, N '-dinitrodiaza alkyl diacid, and can be used for preparing the N, N'-dinitrodiaza alkyl diacid.

Description

Technical Field

[0001] The invention belongs to the technical field of functional material synthesis and relates to a method for preparing a carboxyl-terminated dinitramine compound. The compound can be used as a synthetic precursor of an energetic adhesive for solid propellants. Background Art

[0002] High-energy solid propellant is a polymer composite material with a binder as the matrix and energetic solid particles as the filler. The binder is mainly a polymer material, which is a key component in the core composition of the propellant and the "skeleton" of the solid propellant. The main problem facing solid propellant technology at this stage is how to improve the bottleneck of energy level, and the most critical influencing factor is the polymer binder. At present, most solid propellant-related research uses negative oxygen balance inert binders such as terminal hydroxyl polybutadiene (HTPB), terminal hydroxyl polyether prepolymer (HTPE), and acrylic polymers, which inevitably lead to a decrease in the energy level of explosives. It is necessary to further develop energetic polymer binders to break through the energy performance bottleneck of existing solid propellants.

[0003] End-hydroxyl polyethylene glycol dinitroazaalkanoate polymer (ORP) is a new type of energetic adhesive with high oxygen content, high energy and insensitivity, and low preparation cost. Its main chain contains nitrogen atoms and its side chain contains nitro groups, so it has good compatibility with energetic plasticizers containing nitro groups (such as nitrate esters, geminal dinitro, and nitramine plasticizers), and the propellants made from it have good aging and mechanical properties.

[0004] The preparation of ORP energetic adhesive is divided into two steps: the first step is to prepare the energetic monomer dinitro N,N'-diazaalkyl diacid through Michael addition-nitration-hydrolysis reaction; the second step is to use p-toluenesulfonic acid as a catalyst to generate ORP through esterification reaction of N,N'-dinitrodiazaalkyl diacid and diethylene glycol. Among them, the preparation of the intermediate N,N'-dinitrodiazaalkyl diacid is the key in the preparation process of ORP adhesive, and its synthesis method and product quality have a decisive influence on the synthesis of ORP adhesive.

[0005] At present, the preparation method of energetic monomer N,N'-dinitrodiazaalkyl diacid mainly uses 1,ω-alkyl diamine as raw material, first reacts with acrylonitrile to synthesize N,N'-di(2-cyanoethyl)alkyl diamine dinitrate by Michael addition reaction, and then obtains the target product N,N'-dinitrodiazaalkyl diacid by nitration-hydrolysis reaction. The hydrolysis process needs to be heated and refluxed in concentrated hydrochloric acid. The reaction is a reversible reaction, the reaction time exceeds 16h, and a large amount of concentrated hydrochloric acid is required. This method has the problems of long reaction time, low efficiency, large amount of waste acid, etc., and it is difficult to achieve efficient preparation.

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a method for preparing a carboxyl-terminated dinitramine compound, which overcomes the deficiencies of the prior art in the preparation of N,N'-dinitrodiazaalkyl diacids, such as long hydrolysis reaction time, low reaction efficiency, and large amount of waste acid.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0008] A method for preparing a carboxyl-terminated dinitramine compound, wherein the compound is N,N'-dinitrodiazaalkyl dioic acid. The method uses N,N'-di(2-cyanoethyl)alkyl dinitramine as a raw material, undergoes a hydrolysis reaction under the catalysis of an alkali and an iodide, and then generates N,N'-dinitrodiazaalkyl dioic acid after neutralization with sulfuric acid.

[0009] The present invention also includes the following technical features:

[0010] Specifically, the structural formula of the N,N'-dinitrodiazaalkyl diacid is:

[0011] Among them, R includes -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH(CH3)CH2-, and -CH2CH(CH3)CH2CH2-.

[0012] Specifically, the structural formula of the N,N'-di(2-cyanoethyl)alkyl dinitramine is:

[0013] Among them, R includes -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH(CH3)CH2-, and -CH2CH(CH3)CH2CH2-.

[0014] Specifically, the method comprises the following steps:

[0015] Add N,N'-di(2-cyanoethyl)alkyl dinitramine and alkali metal iodide to 5% to 25% alkaline aqueous solution, heat to boiling for hydrolysis reaction, reaction time 30min to 4h;

[0016] After the hydrolysis reaction is terminated, the reaction solution is cooled in an ice water bath, and the pH is adjusted to 4-5 with 5%-25% dilute acid. A large amount of solid is precipitated, which is filtered to obtain a crude product, which is then recrystallized twice with water to obtain N,N'-dinitrodiazaalkyl diacid.

[0017] Specifically, the alkaline aqueous solution is a 15% NaOH aqueous solution.

[0018] Specifically, the hydrolysis reaction time is 1 hour.

[0019] Specifically, the dilute acid is 10% dilute sulfuric acid.

[0020] Compared with the prior art, the present invention has the following technical effects:

[0021] The synthesis method of the invention is simple to operate and has high efficiency. By changing the hydrolysis reaction catalyst to a base and an alkali metal iodide, the hydrolysis reaction time is shortened to 30 minutes to 4 hours, and there is no need to use a large amount of concentrated hydrochloric acid, and the reaction yield and product purity remain basically unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The hydrogen nuclear magnetic resonance spectrum of N,N'-dinitro-4,7-diaza-1,10-decanedioic acid of the present invention is shown in FIG.

[0023] Figure 2 The carbon nuclear magnetic resonance spectrum of N,N'-dinitro-4,7-diaza-1,10-decanedioic acid of the present invention is shown.

[0024] Figure 3 The infrared spectrum of N,N'-dinitro-4,7-diaza-1,10-decanedioic acid of the present invention is shown in FIG.

[0025] Figure 4 The high performance liquid chromatogram of N,N'-dinitro-4,7-diaza-1,10-decanedioic acid of the present invention is shown. DETAILED DESCRIPTION

[0026] The present invention provides a method for preparing a carboxyl-terminated dinitramine compound, wherein N,N'-di(2-cyanoethyl)alkyl dinitramine is used as a raw material, a hydrolysis reaction is carried out under the catalysis of a base and an iodide, and then the N,N'-dinitrodiazaalkyl diacid is generated after neutralization with sulfuric acid. The synthetic route is as follows:

[0027]

[0028] Among them, the structural formula of N,N'-di(2-cyanoethyl)alkyl dinitramine is:

[0029] R includes -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH(CH3)CH2-, -CH2CH(CH3)CH2CH2- and the like.

[0030] The structural formula of N,N'-dinitrodiazaalkyl diacid is:

[0031] Among them, R includes -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH(CH3)CH2-, -CH2CH(CH3)CH2CH2-, and the like.

[0032] The method comprises the following steps:

[0033] N,N'-di(2-cyanoethyl)alkyl dinitramine and alkali metal iodide are added to a 5% to 25% alkaline aqueous solution, heated to boiling for hydrolysis reaction, and the reaction time is 30 minutes to 4 hours; after the hydrolysis reaction is terminated, the reaction solution is placed in an ice water bath for cooling, and the pH is adjusted to 4 to 5 with 5% to 25% dilute acid, a large amount of solid is precipitated, filtered to obtain a crude product, and then recrystallized twice with water to obtain N,N'-dinitrodiazaalkyl diacid.

[0034] The preparation of the above raw material N, N'-di(2-cyanoethyl)alkyl dinitramine refers to the international patent WO1993 / 13051. Specifically, add 1, ω-alkyl diamine (112 mmol) to 170 mL of ethanol, control the temperature below 45 ° C, and drop 12.5 mL of acrylonitrile. After the addition is complete, react at 45 ° C for 30 minutes, then heat to reflux and continue to react for 30 minutes. After the reaction is completed, stop heating and cool the reaction solution to below 10 ° C. Prepare a solution of 22.4 mL of nitric acid (70%) and 11.2 mL of water, slowly drop it into the reaction solution, and precipitate a white solid. After the addition is complete, cool to 5 ° C and keep for 1 hour, filter, wash the solid with ice methanol, and dry it in an oven to obtain N, N'-di(2-cyanoethyl)alkyl diamine dinitrate. In the temperature range of 0-5°C, N,N'-di(2-cyanoethyl)alkyldiamine dinitrate (0.10 mol) was added in batches to the nitric and sulfuric acid mixture, and the temperature was raised to 15°C for nitration reaction, and the reaction time was 20 minutes. After the reaction was terminated, the reaction mixture was poured into crushed ice, stirred, and filtered.

[0035] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0036] Embodiment 1:

[0037] The present embodiment provides a method for preparing a carboxyl-terminated dinitramine compound. N, N'-di(2-cyanoethyl)ethylenedinitramine (25.62 g, 0.10 mol) and sodium iodide (44.97 g, 0.30 mol) are added to 250 mL of a 15% sodium hydroxide solution, mixed and heated to boiling, and refluxed for 1 hour. After the reaction is terminated, the reaction solution is placed in an ice-water bath, and the pH of the solution is adjusted to 4-5 with 10% sulfuric acid to precipitate white crystals, which are filtered and the crude product is recrystallized twice with water to obtain 28.54 g of white crystalline N, N'-dinitro-4,7-diaza-1,10-decanedioic acid, with a yield of 97.0% and a purity of 99.94% (HPLC, see Figure 4 ).

[0038] The structural formulas of the raw material N,N'-di(2-cyanoethyl)ethylenedinitramine and the product N,N'-dinitro-4,7-diaza-1,10-decanedioic acid in this example are:

[0039] N,N'-bis(2-cyanoethyl)ethylenedinitramine: N,N'-Dinitro-4,7-diaza-1,10-decanedioic acid:

[0040] Structure identification:

[0041] IR (KBr, cm -1 )ν: 3566, 3446 (-OH), 3010 (-CH2), 1715 (C=O), 1508, 1271

[0042] (-NO2), 1213(CO), see Figure 3 ;

[0043] 1 H NMR (DMSO-d6, 500 MHz, ppm), δ: 12.50 (s, 2H), 4.09 (s, 4H), 3.92 (t, 4H), 2.65 (t, 4H), see Figure 1 ;

[0044] 13 C NMR (DMSO-d6, 500 MHz, ppm) δ: 172.8, 49.30, 48.24, 31.36, see Figure 2 ;

[0045] Elemental analysis (C8H 14 N4O8, %):

[0046] Calculated: C, 32.65; H, 4.762; N, 19.05.

[0047] Found: C, 33.04; H, 4.699; N, 19.31.

[0048] The above structural identification data confirm that the substance obtained by this method is indeed the target product N,N'-dinitro-4,7-diaza-1,10-decanoic acid.

[0049] Embodiment 2:

[0050] The present embodiment provides a method for preparing a carboxyl-terminated dinitramine compound. N,N'-di(2-cyanoethyl)ethylenedinitramine (25.62 g, 0.10 mol) and sodium iodide (44.97 g, 0.30 mol) are added to 250 mL of a 15% sodium hydroxide solution, mixed and heated until the solution boils, and refluxed for 2 hours. After the reaction is terminated, the reaction solution is placed in an ice-water bath, and the pH of the solution is adjusted to 4-5 with 10% sulfuric acid to precipitate white crystals, which are filtered and the crude product is recrystallized twice with water to obtain 28.27 g of white crystals with a yield of 96.1% and a purity of 99.24%.

[0051] Embodiment 3:

[0052] The present embodiment provides a method for preparing a carboxyl-terminated dinitramine compound. N,N'-di(2-cyanoethyl)ethylenedinitramine (25.62 g, 0.10 mol) and sodium iodide (44.97 g, 0.30 mol) are added to 250 mL of a 5% sodium hydroxide solution, mixed and heated to boiling, and refluxed for 1 hour. After the reaction is terminated, the reaction solution is placed in an ice-water bath, and the pH of the solution is adjusted to 4-5 with 10% sulfuric acid to precipitate white crystals, which are filtered and the crude product is recrystallized twice with water to obtain 27.07 g of white crystals with a yield of 92.0% and a purity of 99.47%.

[0053] Embodiment 4:

[0054] The present embodiment provides a method for preparing a carboxyl-terminated dinitramine compound. N,N'-di(2-cyanoethyl)ethylenedinitramine (25.62 g, 0.10 mol) and potassium iodide (49.80 g, 0.30 mol) are added to 250 mL of a 15% sodium hydroxide solution, mixed and heated to boiling, and refluxed for 1 hour. After the reaction is terminated, the reaction solution is placed in an ice-water bath, and the pH of the solution is adjusted to 4-5 with 10% sulfuric acid to precipitate white crystals, which are filtered and the crude product is recrystallized twice with water to obtain 26.48 g of white crystals with a yield of 90.0% and a purity of 99.30%.

[0055] Embodiment 5:

[0056] The present embodiment provides a method for preparing a carboxyl-terminated dinitramine compound. N,N'-di(2-cyanoethyl)propane dinitramine (27.02 g, 0.10 mol) and sodium iodide (44.97 g, 0.30 mol) are added to 250 mL of a 15% sodium hydroxide solution, mixed and heated until the solution boils, and refluxed for 1 hour. After the reaction is terminated, the reaction solution is placed in an ice-water bath, and the pH of the solution is adjusted to 4-5 with 10% sulfuric acid to precipitate white crystals, which are filtered and the crude product is recrystallized twice with water to obtain 28.79 g of white crystalline N,N'-dinitro-4,8-diaza-1,11-undecanedioic acid with a yield of 93.4% and a purity of 99.18%.

[0057] The structural formulas of the raw material N,N'-di(2-cyanoethyl)propanedinitramine and the product N,N'-dinitro-4,8-diaza-1,11-undecanedioic acid in this example are respectively:

[0058] N,N'-bis(2-cyanoethyl)propanedinitramine: N,N'-Dinitro-4,8-diaza-1,11-undecanedioic acid:

[0059] Embodiment 6:

[0060] The present embodiment provides a method for preparing a carboxyl-terminated dinitramine compound. N,N'-di(2-cyanoethyl)butylene dinitramine (28.43 g, 0.10 mol) and sodium iodide (44.97 g, 0.30 mol) are added to 250 mL of a 15% sodium hydroxide solution, mixed and heated until the solution boils, and refluxed for 1 hour. After the reaction is terminated, the reaction solution is placed in an ice-water bath, and the pH of the solution is adjusted to 4-5 with 10% sulfuric acid to precipitate white crystals, which are filtered and the crude product is recrystallized twice with water to obtain 29.23 g of white crystals with a yield of 90.7% and a purity of 99.11%.

[0061] The structural formulas of the raw material N,N'-di(2-cyanoethyl)butylene dinitramine and the product N,N'-dinitro-4,9-diaza-1,12-dodecanedioic acid in this example are:

[0062] N,N'-bis(2-cyanoethyl)butylene dinitramine: N,N'-dinitro-4,9-diaza-1,12-dodecanedioic acid:

Claims

1. A method for preparing a carboxyl-terminated dinitramine compound, characterized in that: The compound is N,N'-dinitrodiazaalkyl diacid. The method uses N,N'-di(2-cyanoethyl)alkyl dinitramine as a raw material, undergoes a hydrolysis reaction under the catalysis of alkali and iodide, and then generates N,N'-dinitrodiazaalkyl diacid after neutralization with sulfuric acid.

2. The method for preparing a carboxyl-terminated dinitramine compound according to claim 1, wherein The structural formula of the N,N'-dinitrodiazaalkyl diacid is: Among them, R includes -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH(CH3)CH2-, and -CH2CH(CH3)CH2CH2-.

3. The method for preparing a carboxyl-terminated dinitramine compound according to claim 1, wherein The structural formula of the N,N'-di(2-cyanoethyl)alkyl dinitramine is: Among them, R includes -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH(CH3)CH2-, and -CH2CH(CH3)CH2CH2-.

4. The method for preparing a carboxyl-terminated dinitramine compound according to claim 1, wherein The method comprises the following steps: Add N,N'-di(2-cyanoethyl)alkyl dinitramine and alkali metal iodide to 5% to 25% alkaline aqueous solution, heat to boiling for hydrolysis reaction, reaction time 30min to 4h; After the hydrolysis reaction is terminated, the reaction solution is cooled in an ice water bath, and the pH is adjusted to 4-5 with 5%-25% dilute acid. A large amount of solid is precipitated, which is filtered to obtain a crude product, which is then recrystallized twice with water to obtain N,N'-dinitrodiazaalkyl diacid.

5. The method for preparing a carboxyl-terminated dinitramine compound according to claim 4, wherein: The alkaline aqueous solution is a 15% NaOH aqueous solution.

6. The method for preparing a carboxyl-terminated dinitramine compound according to claim 4, wherein: The hydrolysis reaction time is 1 h.

7. The method for preparing a carboxyl-terminated dinitramine compound according to claim 4, wherein: The dilute acid is 10% dilute sulfuric acid.

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