KR102144820B1 - Method for preparing polymer comprising 5-aminotetrazole and polymer comprising 5-aminotetrazole - Google Patents

Abstract

The present invention relates to a method for preparing a high-energy 5-aminotetrazole-containing polymer, and a high-energy 5-aminotetrazole-containing polymer. Particularly, the method for preparing a high-energy 5-aminotetrazole-containing polymer includes a step of introducing 5-aminotetrazole represented by the following chemical formula (I) to a polyepihalohydrin represented by the following chemical formula (II) through nucleophilic substitution in the presence of an alkali metal hydroxide to obtain a polymer represented by the following chemical formula (IIIa). In chemical formula (IIIa), each substituent has the same meaning as defined in claim 1.

Description

Manufacturing method of 5-aminotetrazole high-energy polymer and 5-aminotetrazole high-energy polymer {METHOD FOR PREPARING POLYMER COMPRISING 5-AMINOTETRAZOLE AND POLYMER COMPRISING 5-AMINOTETRAZOLE}

The present invention relates to a method for producing a high-nitrogen-containing material, a 5-aminotetrazole high-energy-containing polymer, and to a 5-aminotetrazole high-energy-containing polymer.

When a high-energy material is introduced into a polymer, thermal stability is increased due to the effect of mitigating the physical stress applied to the high-energy material by the long carbon chains of the polymer. Therefore, polymers containing high-energy materials have been usefully used as polymer fuels and binders for propellants with thermal stability, or gas generators for automobile airbags. Among them, GAP (Glycidyl azide polymer) is the most representative high-energy polymer, and the azide group has a high amount of heat of generation (+ 957 kJ/mol), so it has excellent explosive performance as well as insensitivity to thermal and mechanical stimulation. . However, when it is applied to a propellant, in addition to environmental problems caused by the toxicity of azide groups, pot-life during curing is shortened due to the reactivity of azide groups, and when stored for a long time, voids are generated due to nitrogen generation due to decomposition. However, there is a disadvantage that can reduce the properties of the propellant. To solve these problems, research has been conducted to replace azide with an eco-friendly and stable tetrazole (Aronson JB. [dissertation] Atalanta (GE): Georgia Inttitute of Technology, 2004).

However, in this process, as the content of tetrazole increased, the polymer became hard and fragile, and the amount of energy generated was slightly decreased compared to the azide group. Therefore, a method of synthesizing a copolymer including tetrazole and an azide group that can control physical properties and processability while maintaining high energy characteristics depending on the use is required.

In the conventional method of converting the azide group of GAP to a tetrazole group, a polymer including tetrazole was synthesized through a two-step reaction followed by a click reaction between alkyl cyanoformates and a decarboxylation reaction as shown in Scheme 1 below.

[Scheme 1]

Alkyl cyanoformate used in a large amount in the above reaction is not produced in Korea and is difficult to handle as a highly toxic substance. In addition, since the starting material GAP must be synthesized through a two-step reaction with a long reaction time, the process may be complicated and cost may increase.

Accordingly, there is a need to develop a new manufacturing method capable of producing a polymer containing tetrazole without using a toxic substance such as cyanoformate through a simple process.

The present invention is to solve the above problems, in a simple and safe synthesis process, 5-aminotetrazole groups and azido groups, which are high-energy substances containing high nitrogen, are introduced into the side chains of a polyepihalohydrin-based polymer. It is to provide a method for producing a polymer, which is easy to control the content of, and can be utilized as a mass production technology.

The present invention is to provide a polymer that includes a 5-aminotetrazole group and an azido group introduced in various amounts and can be utilized as a high energy material.

However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present invention, a 5-amino tetrazole represented by formula (I) is introduced into the polyepihalohydrin represented by formula (II) through a nucleophilic substitution reaction in the presence of an alkali metal hydroxide. Synthesizing a polymer represented by (IIIa); It relates to a method for producing a polymer comprising a.

Formula (I)

Formula (II)

Formula (IIIa)

(Wherein, X is selected from Cl, Br or I,

a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.)

According to an embodiment of the present invention, in the step of synthesizing the polymer represented by Formula (IIIa), the reaction ratio of the 5-amino tetrazole is 10% to 90% of the repeating unit of the polyepihalohydrin. Can be.

According to an embodiment of the present invention, the alkali metal hydroxide may include at least one selected from the group consisting of sodium hydroxide (NaOH) 　, potassium hydroxide (KOH), and lithium hydroxide (LiOH).

According to an embodiment of the present invention, the preparation method includes the steps of synthesizing a polymer represented by the following formula (IIIb) by introducing an azido group into the leaving group (X) of the polymer represented by the formula (IIIa); It may be to further include.

Formula (IIIb)

(Here, a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.)

According to an embodiment of the present invention, the step of synthesizing the polymer represented by the formula (IIIb) is azide reaction by adding sodium azide in a single container reaction after synthesizing the polymer represented by formula (IIIa). It may be to proceed.

According to an embodiment of the present invention, the step of synthesizing the polymer represented by Formula (IIIb) may be heating to 50° C. or higher to perform an azide reaction.

According to an embodiment of the present invention, the sodium azide may be added in a molar ratio of 0.1 to 9 relative to the 5-amino tetrazole added during the synthesis of the polymer represented by Formula (IIIa).

According to an embodiment of the present invention, the step of synthesizing the polymer represented by Formula (IIIa) comprises mixing the alkali metal hydroxide, the 5-amino tetrazole, and the polyepihalohydrin to form a reaction mixture. Manufacturing steps; And heating the reaction mixture to 50° C. or higher to proceed with the reaction. It may be to include.

According to an embodiment of the present invention, a post-treatment step of cooling the reactant after the step of synthesizing the polymer represented by Formula (IIIa), and removing by-products using cooling water of 0° C. to 5° C.; It may be to further include.

According to an embodiment of the present invention, it relates to a polymer represented by the following formula (IIIa) or formula (IIIb).

Formula (IIIa)

(Wherein, X is selected from Cl, Br or I, a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23 .)

Formula (IIIb)

(Here, a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.)

According to an embodiment of the present invention, the polymer may be manufactured by the manufacturing method according to the present invention.

According to an embodiment of the present invention, the polymer may be applied as a polymer fuel or a binder as a propellant.

In the present invention, a tetrazole group, or a polymer including a tetrazole group and an azide group can be synthesized and the content thereof can be easily controlled.In particular, the 5-aminotetrazole and azide groups, which have the highest nitrogen content of 80%, are It is possible to provide a method for preparing a copolymer composed of various ratios.

In the present invention, it is necessary to separate only 1-substituents with high stability among the isomers generated when synthesizing bis- or tris-type multitetrazole low-molecular derivatives through alkylation of 5-aminotetrazole. In the case of the present invention in which the tetrazole is introduced into the polymer, the separation process is not required due to the stability imparted from the polymer, and thus the effect of reducing the production cost can be secured.

The present invention can provide an easier, safer and more economical method for producing a copolymer composed of 5-aminotetrazole and azide groups in various ratios. Through this, the content of the azide group and the 5-aminotetrazole group in the polymer can be easily controlled, so that a polymer can be easily synthesized that compensates for the processability and stability problems of each of these two monomers or the disadvantages of performance reduction depending on the application.

1 shows IR spectra of poly(GA-co-GAT) prepared in an embodiment of the present invention, according to an embodiment of the present invention.
2 shows ¹ H NMR spectra of poly(GA-co-GAT) prepared in an example of the present invention, according to an embodiment of the present invention.
3 shows GPC chromatograms of poly(GA-co-GAT) prepared in an example of the present invention according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms used in the present specification are terms used to properly express a preferred embodiment of the present invention, which may vary depending on the intention of users or operators, or customs in the field to which the present invention belongs. Accordingly, definitions of these terms should be made based on the contents throughout the present specification. The same reference numerals in each drawing indicate the same members.

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components.

The present invention relates to a method of preparing a high-energy polymer containing 5-aminotetrazole, and according to an embodiment of the present invention, the preparation method comprises a 5-aminotetrazole group and a sub-chain in the side chain of the polyepihalohydrin. A high-energy material-containing polymer is manufactured using a process of introducing a zide group. That is, the present invention provides a copolymer in which the content of 5-aminotetrazole and azide is controlled by using polyepichlorohydrin, 5-aminotetrazole, and sodium azide as raw materials and applying various reaction ratios. can do.

According to an embodiment of the present invention, it may include synthesizing a polymer represented by formula (IIIa) and synthesizing a polymer represented by formula (IIIb).

According to an embodiment of the present invention, the step of synthesizing the polymer represented by formula (IIIa) is to polyepile the 5-amino tetrazole represented by formula (I) by a nucleophilic substitution reaction in the presence of an alkali metal hydroxide. It is a step of introducing into the side chain of rohydrin,

The 5-amino tetrazole is represented by the following formula (I), and the polyepihalohydrin may include one or more of the compounds represented by the following formula (II).

Formula (I)

Formula (II)

Formula (IIIa)

In the above formulas (II) and (IIIa), X is selected from F, Cl, Br or I, a is 15 to 25, the sum of b, c and d is 15 to 25, and the sum of b and d is 1 To 18 and c is 4 to 23.

The alkali metal hydroxide may include at least one selected from the group consisting of sodium hydroxide (NaOH) 　, potassium hydroxide (KOH), and lithium hydroxide (LiOH), but is not limited thereto.

The step of synthesizing the polymer represented by Formula (IIIa) is to first introduce 5-aminotetrazole into the polymer through a nucleophilic substitution reaction between polyepichlorohydrin and 5-aminotetrazole. Preparing a reaction mixture by mixing the alkali metal hydroxide, 5-amino tetrazole, and polyepihalohydrin according to 2; And heating the reaction mixture to proceed with the reaction.

[Scheme 2]

5-aminotetrazole, which is a commonly used raw material, is mainly obtained from a mixture of isomers in which a substituent is bonded at the 1st or 2nd position during a nucleophilic substitution reaction. The process must be carried out essentially. However, due to the effect of increasing stability when 5-aminotetrazole is introduced into a polymer through a nucleophilic substitution reaction according to Scheme 2 of the present invention, a large amount of 5-aminotetrazole-based polymer is safer without the need for this isomer separation process. It is possible to secure a synthetic process capable of producing energetic substances.

The step of performing the reaction by heating the reaction mixture is a step of reacting a reaction mixture of polyepihalohydrin and 5-aminotetrazole in the presence of an alkali metal hydroxide catalyst, for example, 50° C. or higher; 80°C to 120°C; Or heating the reaction mixture to a temperature of 90° C. to 110° C. for 1 hour or more; More than 10 hours; 20 to 30 hours; Alternatively, it may be reacted for 23 to 24 hours.

The reaction ratio of the 5-aminotetrazole can be adjusted to 10% to 90% of the repeating unit of the polyepihalohydrin, and the substitution of the aminotetrazole can occur simultaneously at the 1st and 2nd positions of the tetrazole. In addition, the ratio of repeating units having different substitution positions can be appropriately adjusted.

A solvent is further included in the reaction mixture, and the solvent may include at least one selected from the group consisting of dimethyl sulfoxide, dimethylformamide, and dimethylacetamide.

After the step of synthesizing the polymer represented by Formula (IIIa), a post-treatment step of cooling the reactant and removing by-products using cooling water at the same time; may further include. That is, in the post-treatment after the nucleophilic substitution reaction, the polymer is precipitated using cooling water and cooling water of the reactant, and after separating the polymer, the by-product is removed by separating the polymer by centrifugation after applying ultrasonic waves by adding cooled water to it. I can.

The step of removing the by-products, 0 ~ 10 ℃; Alternatively, the process of adding cooling water of 0 to 5° C. and removing by-products may be performed twice or more.

The step of synthesizing the polymer represented by the formula (IIIb) is a polymer represented by the formula (IIIb) through a sequential nucleophilic substitution reaction of polyepihalohydrin, 5-aminotetrazole, and an azide group, Synthesize “poly(GA-co-GAT)”. After synthesizing the polymer represented by the above formula (IIIa), sodium azide is added in a one-pot reaction to proceed with an azide reaction.Substitution of 5-aminotetrazole according to the following Scheme 3 After the reaction proceeds, a one-pot reaction in which sodium azide is added to replace the azide group in the C-Cl group of the remaining glycidyl chloride portion can be performed to synthesize a polymer represented by the formula (IIIb).

Formula (IIIb)

In Formula (IIIb), a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.

[Scheme 3]

The step of synthesizing the polymer represented by the formula (IIIb), the azide reaction by sodium azide is 50 ℃ or more; 80°C to 120°C; 15 hours to 24 hours by heating the reaction mixture to a temperature of 90 ℃ to 110 ℃; Alternatively, it can be reacted for 19 hours to 21 hours.

The sodium azide may be added in a molar ratio of 0.1 to 9 with respect to the 5-aminotetrazole added during the synthesis of the polymer represented by Formula (IIIa).

The sodium azide is added to the reaction mixture after the step of synthesizing the polymer represented by formula (IIIa) to proceed with an azide reaction, or after removing the reactant, a solvent and sodium azide may be added to proceed with the azide reaction. I can.

The present invention relates to a 5-aminotetrazole high energy-containing polymer, and according to an embodiment of the present invention, it may be a polymer represented by the following formula (IIIa) or (IIIb).

Formula (IIIa)

In the formula (IIIa), X is selected from Cl, Br or I, a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 To 23.)

Formula (IIIb)

In Formula (IIIb), a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.

The polymer exhibits high-energy material properties, and it is possible to secure poly(GA-co-GAT) of various compositions, so that it may be a product applicable to high-energy materials such as a polymer fuel for a propellant or a binder, and an automobile airbag gas generator. have.

Hereinafter, a method of preparing the polymer of Formula (II) (poly(GA-co-GAT)) according to the synthetic route of Scheme 1 will be described in detail through examples.

The reaction ratios used in the examples are summarized in Table 1. Polyepichlorohydrin used as a raw material was synthesized by cationic polymerization of epichlorohydrin using ethylene glycol as an initiator under BF ₃ -etherate catalyst using the reported synthesis process ( J. Polym. Sci. A Polym. Chem., 29 , 619 (1991)).

[Scheme 1]

Example 1

Polyepichlorohydrin 1 g (PECH, 11 mmol; repeating unit molecular weight: 92.52) and 5-aminotetrazole 0.09 g (1 mmol) were dissolved in 10 ml of DMSO, sodium hydroxide 0.04 g (1 mmol) was added, and the mixture Was stirred for 24 hours while heating at 100°C. After the reaction was completed, the mixture was cooled to room temperature, 0.6 g (9 mmol) of sodium azide was added to the reaction mixture, and the mixture was stirred for 19 hours while heating to 100°C. After completion of the reaction, the reaction solution was cooled to 4° C., and 20 ml of distilled water cooled to 4° C. was added thereto. After removing the supernatant by centrifuging the resulting suspension, 20 ml of water was added to the obtained polymer, and ultrasonic waves were applied for 3 minutes to re-create the suspension, followed by centrifugation and repeating the process of removing the supernatant twice, and then dichloromethane. After dissolving in magnesium sulfate, dried over magnesium sulfate, filtered, concentrated, and dried to obtain a polymer in the form of an amber oil (yield 67%).

Example 2

It was carried out in the same manner as in Example 1. At this time, polyepichlorohydrin 1 g (11 mmol; repeat unit molecular weight: 92.52), 5-aminotetrazole 0.28 g (3 mmol), sodium hydroxide 0.13 g (3 mmol) and sodium azide 0.5 g (7 mmol) ) Was synthesized (yield 79%).

Example 3

It was carried out in the same manner as in Example 1. Polyepichlorohydrin 1 g (11 mmol; repeating unit molecular weight: 92.52), 5-aminotetrazole 0.46 g (5 mmol), sodium hydroxide 0.22 g (5 mmol) and sodium azide 0.35 g (5 mmol) It was synthesized using (62% yield).

Example 4

It was carried out in the same manner as in Example 1. Polyepichlorohydrin 1 g (11 mmol; repeat unit molecular weight: 92.52), 5-aminotetrazole 0.64 g (7 mmol), sodium hydroxide 0.30 g (7 mmol) and sodium azide 0.21 g (3 mmol) It was synthesized using (yield 45%).

Example 5

It was carried out in the same manner as in Example 1. Polyepichlorohydrin 1 g (11 mmol; repeating unit molecular weight: 92.52), 5-aminotetrazole 0.82 g (9 mmol), sodium hydroxide 0.38 g (9 mmol) and sodium azide 0.07 g (1 mmol) And synthesized (yield 94%).

Experiment result

The properties of Poly(GA-co-GAT) are shown in Table 1 below. Meanwhile, poly(GA) by detection of the characteristic absorption band of the tetrazole ring at 1640-1335 cm ^-1 in addition to the characteristic peak of the azide group at 2100 cm ^-1 when compared with the precursor PECH through the FT-IR analysis of FIG. 1 -co-GAT) was successfully synthesized, and at the same time, an increase or decrease in peak intensity was observed according to their ratio. In addition, it was possible to confirm the introduction of 5-aminotetrazole and azide groups through ¹ H NMR and ¹³ C NMR. In particular, ^1- substituted at 7.2 ppm and 2-substituted at 6 ppm as shown in FIG. 2 in ¹ H NMR. The peak of -NH ₂ of the 5-aminotetrazole was confirmed, and the 1- and 2-substituted ratios of 5-aminotetrazole were confirmed using the area ratio. In addition, the copolymer composition (mol ratio) was confirmed by calculating the number of hydrogens in each copolymer unit in the main chain appearing between 5.0 and 3.0 ppm using the sum of the number of hydrogens of the peaks of -NH ₂ .

Example: Composition of Example 1 (GA: GAT) calculation result

GA; I _{5.0 to 3.0 ppm} (area integral value of 2, 3, 4, 5, 6, 7, 8, 9, 10 peaks)

-[I _{7.2 ppm} + I _{6.0 ppm} (sum of area integral values of peaks 1 and 11)]* 2.5

GAT; [I _{7.2 ppm} + I _{6.0 ppm} (sum of area integral values of peaks 1 and 11)]* 2.5

Detailed results are shown in Table 1.

On the other hand, the molecular weight (Mn) of each poly(GA-co-GAT) ranged from 3600 to 6000, and showed a tendency to increase as the content of GAT increased, and the PDI was 1.23 to 1.36, having an unimodal distribution as shown in FIG. 3.

Example Copolymer mol ratio
(azide: tetrazole) Mol ratio
(1-substitution: 2-substitution) Molecular weight (g/mol) Theoretical value Experimental value Mn PDI PECH 2064 1.34 One 9: 1 (1: 0.11) 1: 0.07 1: 0.89 3600 1.31 2 7: 3 (1: 0.43) 1: 0.29 1: 0.86 4300 1.36 3 5: 5 (1: 1) 1: 0.69 1: 0.87 5000 1.33 4 3: 7 (1: 2.3) 1: 1.19 1: 0.89 5700 1.25 5 1: 9 1: 2.44 1: 0.91 6000 1.23

The present invention can provide a method for synthesizing a high-energy polymer including 5-aminotetrazole and an azido group, which is a high-energy substance through a stepwise nucleophilic substitution reaction, and the method has a simple and economical manufacturing process. , By easily adjusting the content of the two functional groups in the polymer, a desired composition or a copolymer of various compositions (poly(glycidyl azide-co-glycidyl 5-aminotetrazole (poly(GA-co-GAT))) can be synthesized.

In the present invention, the method for producing a high-energy-containing polymer including both 5-aminotetrazole and azido groups is very simple with a stepwise single-container reaction, so that even a mass production process can be secured, and for research on high-energy substances and product production Can be used as a technology.

As described above, although the embodiments have been described by the limited drawings, a person of ordinary skill in the art can apply various technical modifications and variations based on the above. For example, the described techniques are performed in an order different from the described method, and/or components such as a system, structure, device, circuit, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and claims and equivalents fall within the scope of the following claims.

Claims (13)

In the presence of an alkali metal hydroxide, a polymer represented by the formula (IIIa) is synthesized by introducing 5-aminotetrazole represented by the formula (I) into the polyepihalohydrin represented by the formula (II) through a nucleophilic substitution reaction. Step to do;
Containing,
Polymer preparation method:

Formula (I)

Formula (II)

Formula (IIIa)

(Wherein, X is selected from Cl, Br or I,
a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.)
The method of claim 1,
In the step of synthesizing the polymer represented by Formula (IIIa), the reaction ratio of the 5-amino tetrazole is 10 to 90 mol% of the repeating unit of the polyepihalohydrin,
Method for producing a polymer.
The method of claim 1,
The alkali metal hydroxide comprises at least one selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH) and lithium hydroxide (LiOH),
Method for producing a polymer.
The method of claim 1,
The manufacturing method includes the steps of synthesizing a polymer represented by the following formula (IIIb) by introducing an azido group into the leaving group (X) of the polymer represented by the formula (IIIa);
The method of manufacturing a polymer that further comprises:

Formula (IIIb)

(Here, a is 15 to 25, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.)
The method of claim 4,
The step of synthesizing the polymer represented by Formula (IIIb) is to proceed with an azide reaction by adding sodium azide in a single container reaction after synthesizing the polymer represented by Formula (IIIa),
Method for producing a polymer.
The method of claim 4,
The step of synthesizing the polymer represented by the formula (IIIb) is to proceed with the azide reaction by heating to 50 ℃ or more,
Method for producing a polymer.
The method of claim 5,
The sodium azide is added in a molar ratio of 0.1 to 9 relative to the 5-aminotetrazole added during the synthesis of the polymer represented by Formula (IIIa),
Method for producing a polymer.
The method of claim 1,
The step of synthesizing the polymer represented by the formula (IIIa) may include preparing a reaction mixture by mixing the alkali metal hydroxide, the 5-amino tetrazole, and the polyepihalohydrin; And
Heating the reaction mixture to 50° C. or higher to proceed with the reaction;
It includes,
Method for producing a polymer.
The method of claim 1,
A post-treatment step of cooling the reaction product after the step of synthesizing the polymer represented by the formula (IIIa), and simultaneously removing by-products using cooling water at 0°C to 5°C;
Which further comprises,
Method for producing a polymer.
A polymer represented by the following formula (IIIa):
Formula (IIIa)

(Wherein, X is selected from Cl, Br or I,
The sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.)
A polymer represented by the following formula (IIIb):
Formula (IIIb)

(Here, the sum of b, c and d is 15 to 25, the sum of b and d is 1 to 18, and c is 4 to 23.)
The method of claim 10,
The polymer is prepared by the method of claim 1,
Polymer.
The method of claim 10 or 11,
The polymer is applied as a polymer fuel or a binder of a propellant,
Polymer.

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