CN114436986B

CN114436986B - Preparation method of pentazole negative ions

Info

Publication number: CN114436986B
Application number: CN202210065796.3A
Authority: CN
Inventors: 陆明; 蔡春; 王鹏程; 陆国平; 许元刚; 林秋汉; 张晓鹏; 侯天阳
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2023-01-20
Anticipated expiration: 2042-01-20
Also published as: CN114436986A

Abstract

The invention discloses a preparation method of pentazole anions, which takes ozone as an oxidant and selectively cuts C-N bonds in aryl pentazole under the catalysis of organic ferrous salt to obtain the pentazole total nitrogen anions. The invention adopts the ozone oxidant to replace the prior organic peroxide, not only improves the safety of the preparation process, but also avoids the post-treatment of peroxide residues; the organic ferrous salt used in the invention increases the solubility in organic solvent, can improve the catalytic efficiency and obviously improves the yield.

Description

Preparation method of pentazole negative ions

Technical Field

The invention belongs to the technical field of energetic materials, and relates to a method for preparing pentaconazole anions by selectively cutting off a C-N bond in aryl pentaconazole through ozone oxidation.

Background

The pentazole negative ion serving as a total nitrogen ion can release ultrahigh energy, and is a new generation of energetic material candidate. According to reported documents (Nature, 2017, 549,78-81), the preparation method of the pentazole negative ion mainly adopts m-chloroperoxybenzoic acid as an oxidant, ferrous glycinate as a catalyst, and aryl pentazole cuts off a C-N bond in the pentazole so as to obtain the pentazole negative ion. Due to the instability of peroxide, excessive unreacted m-chloroperoxybenzoic acid in the reaction system may have the risk of decomposition and explosion during the post-treatment, and has great safety influence. In addition, the reaction conversion rate of the system reported in the literature is lower than 10%, which is not beneficial to further scale production.

Therefore, it is necessary to develop a safe and efficient selective oxidative cleavage reaction system suitable for engineering scale-up to solve the above problems.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a method for selectively cutting off C-N bonds in aryl pentazole by ozone oxidation.

In order to achieve the above purpose, the invention adopts the following technical scheme:

a method for preparing pentaconazole negative ions by selectively cutting off C-N bonds in aryl pentaconazole through ozone oxidation comprises the step of carrying out oxidation reaction on aryl pentaconazole I under the catalytic action of organic ferrous iron in an ozone environment to cut off the C-N bonds in the aryl pentaconazole to prepare the pentaconazole negative ions II,

preferably, the reaction system adopts one or more of methanol, ethanol, acetonitrile and tetrahydrofuran as a solvent.

Preferably, the organic ferrous iron is selected from one or more of ferrous protoporphyrin (heme), ferrous glycinate and ferrous phthalocyanine.

Preferably, the reaction temperature is-20 to-10 ℃; the reaction time is 4 to 10 hours.

Preferably, the molar ratio of the organic ferrous iron to the arylpentazole is 1:1 to 1:3.

preferably, the molar ratio of the total amount of ozone to the arylpentazoles is 1:4 to 1:6.

preferably, the pressure of the reaction apparatus is 1 to 2 atmospheres during the reaction.

Compared with the prior art, the invention has the beneficial effects that:

(1) The method for selectively cutting off the C-N bond in the aryl pentazole by ozone oxidation has the characteristic of high safety. The adopted oxidant is ozone, air or oxygen is used as a raw material and is prepared by an ozone generator, and after the reaction is finished, nitrogen is blown in a reaction solvent to take away residual ozone, so that no peroxide residue exists in a reaction system, and the safety of aftertreatment is ensured.

(2) The method for cutting off the C-N bond in the arylpentazole by the ozone and organic ferrous iron catalyst concerted catalysis has the characteristic of high efficiency. Through ion chromatographic analysis, the conversion rate can be improved to 42% by using ozone and an organic ferrous catalyst in the reaction system, which is 4 times that of the existing literature method (Nature, 2017, 549,78-81), and the improvement effect is obvious.

Drawings

FIG. 1 is a high resolution mass spectrum of example 1 of the present invention.

FIG. 2 is an ion chromatogram of example 1 of the present invention.

FIG. 3 is a high resolution mass spectrum of example 4 of the present invention.

FIG. 4 is an ion chromatogram of example 4 of the present invention.

FIG. 5 is a high resolution mass spectrum of example 5 of the present invention.

FIG. 6 is an ion chromatogram of example 5 of the present invention.

FIG. 7 is a high resolution mass spectrum of example 6 of the present invention.

FIG. 8 is an ion chromatogram of example 6 of the present invention.

FIG. 9 is a high resolution mass spectrum of example 7 of the present invention.

FIG. 10 is an ion chromatogram of example 7 of the present invention.

FIG. 11 is a high resolution mass spectrum of example 8 of the present invention.

FIG. 12 is an ion chromatogram of example 8 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The method for preparing the pentazole negative ions comprises the following steps:

1) Preparing an organic solution of aryl pentazole under the low temperature condition of-20 to-10 ℃, and stirring to uniformly disperse the organic solution, wherein the organic solvent is one or more of methanol, ethanol, acetonitrile and tetrahydrofuran, and the aryl pentazole comprises 4-hydroxyaryl pentazole, 4-aminoarylpentazole, 3,5-dimethyl-4-hydroxyaryl pentazole and 3,5-dimethyl-4-aminoarylpentazole shown in the following formula;

2) Adding an organic ferrous iron catalyst into the solution under the condition of stirring, wherein the organic ferrous iron is selected from one or more of ferrous iron protoporphyrin (heme), ferrous glycine and ferrous phthalocyanine, and the molar ratio of the organic ferrous iron to the arylpentazole is 1:1 to 1:3;

3) Continuously introducing ozone into the solution obtained in the step 2) at the temperature of between 20 ℃ below zero and 10 ℃ below zero for reaction for 4 to 10 hours, wherein the pressure of a reaction device during the reaction is 1 to 2 atmospheric pressures;

4) After the reaction is finished, removing the solvent by rotary evaporation, and washing with ethyl acetate to obtain a crude product;

5) Dissolving the crude product obtained in the step 4) in ethanol for column separation to obtain a target compound, wherein a column separation mobile phase is a mixed solvent of ethyl acetate and ethanol, and the volume ratio of the solvent is 1:1 to 10:1.

example 1

Adding a mixed organic solution of 75mL of methanol and 75mL of acetonitrile into a 500-neck flask, placing the mixture into a low-temperature reactor, cooling the mixture to-20 ℃, adding 19.1g of 3, 5-dimethyl-4-hydroxyaryl pentazole (substrate 1, 0.1mol), uniformly stirring, and adding 65g of ferrous protoporphyrin (0.1 mol) into the organic solution in batches. Keeping the stirring speed at 400 r/min, continuously and stably introducing ozone gas, and respectively arranging an ozone detector at the gas inlet and the gas outlet to detect the ozone concentration at the gas inlet and the gas outlet. Through calculation, when the ozone air inflow reaches 0.6mol, the reaction solution is detected by mass spectrometry, the generation of the pentazole negative ions is confirmed, the reaction solution is detected by ion chromatography, and the theoretical conversion rate is 42%. The ozone gas was removed and the nitrogen gas was replaced with nitrogen gas and the bubbling was continued for 0.5 hour. Then the reaction solution is filtered and steamed in a rotary way to obtain a crude product, which is washed by 100ml of ethyl acetate and then dissolved in a trace amount of ethanol to prepare sand. And finally, adding ethyl acetate: ethanol volume ratio of 1:1 is mobile phase, and is separated and purified by a silica gel column to obtain the pentazole anion solid with the yield of 29 percent. The characterization results are shown in fig. 1 and 2, in fig. 1, m/z =70.0144 is a pentazole anion; in fig. 2, t =16.133min is the pentazole anion.

Example 2

The reaction solution was detected by mass spectrometry and ion chromatography in the same manner as in example 1 except that the ozone gas in example 1 was changed to oxygen gas, and it was confirmed that no pentazole negative ion was generated.

Example 3

The procedure of example 1 was otherwise the same as that of example 1 except that the ferriprotoporphyrin in example 1 was changed to porphyrin, and the reaction solution was detected by mass spectrometry and ion chromatography to confirm that no pentaconazole anion was generated.

Example 4

The 3,5-dimethyl-4-hydroxyaryl pentazole in example 1 was changed to 4-hydroxyaryl pentazole (substrate 2), and the other implementation steps were the same as in example 1, and the reaction solution was examined by mass spectrometry and ion chromatography, confirming that the anion of pentazole was generated, the theoretical conversion was 29%, and the yield was 12%. The characterization results are shown in fig. 3 and 4, wherein m/z =70.0144 is the anion of pentazole in fig. 3, and t =17.050min is the anion of pentazole in fig. 4.

Example 5

The 3,5-dimethyl-4-hydroxyaryl pentazole in example 1 was changed to 4-aminoarylpentazole (substrate 3), and the reaction solution was examined by mass spectrometry and ion chromatography in the same manner as in example 1, to confirm that the anion of pentazole was formed, with a theoretical conversion of 25% and a yield of 16%. The characterization results are shown in fig. 5 and 6, wherein m/z =70.0144 is the anion of pentazole in fig. 5, and t =17.043min is the anion of pentazole in fig. 6.

Example 6

The 3,5-dimethyl-4-hydroxyaryl pentazole in example 1 was changed to 3,5-dimethyl-4-aminoarylpentazole (substrate 4), and the reaction solution was examined by mass spectrometry and ion chromatography in the same manner as in example 1, whereby formation of a pentazole anion was confirmed, the theoretical conversion was 34%, and the yield was 23%. The characterization results are shown in fig. 7 and 8, wherein m/z =70.0144 is the anion of pentazole in fig. 7, and t =17.027min is the anion of pentazole in fig. 8.

Example 7

The ferrous protoporphyrin in example 1 was changed to ferrous glycinate, and the other steps were performed in the same manner as in example 1, and the reaction solution was detected by mass spectrometry and ion chromatography, whereby the formation of pentazole negative ions was confirmed, the theoretical conversion was 39%, and the yield was 28%. The characterization results are shown in fig. 9 and 10, wherein m/z =70.0144 is the anion of pentazole in fig. 9, and t =17.020min is the anion of pentazole in fig. 10.

Example 8

The reaction solution was examined by mass spectrometry and ion chromatography using the same procedure as in example 1 except that the ferrous protoporphyrin in example 1 was changed to ferrous phthalocyanine, and it was confirmed that pentazole negative ion was generated, the theoretical conversion rate was 10%, and the yield was 6%. The characterization results are shown in fig. 11 and 12, wherein m/z =70.0144 is the pentazole anion in fig. 11, and t =15.867min is the pentazole anion in fig. 12.

Example 9

The reaction solution was examined by mass spectrometry and ion chromatography in the same manner as in example 1 except that 65g of ferrous protoporphyrin in example 1 was increased to 130g, and it was confirmed that a pentazole negative ion was formed, the theoretical conversion rate was 41%, and the yield was 28%.

Example 10

The amount of ozone introduced in example 1 was reduced to 0.6mol and the reaction mixture was examined by mass spectrometry and ion chromatography in the same manner as in example 1, thereby confirming that the anion of pentazole was formed, the theoretical conversion was 37%, and the yield was 26%.

The data relating to the theoretical conversion and yield obtained in the examples of the invention are summarized in table 1 below.

TABLE 1

Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More specifically, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.

Claims

1. A method for preparing pentazole negative ions is characterized by comprising the steps of carrying out oxidation reaction on aryl pentazole I under the catalytic action of organic ferrous iron in an ozone environment to cut off C-N bonds in the aryl pentazole to prepare the pentazole negative ions II,

wherein, the reaction system adopts a mixed solution of methanol and acetonitrile as a solvent;

the organic ferrous iron is selected from one or more of ferrous protoporphyrin, ferrous glycinate and ferrous phthalocyanine;

the reaction temperature is-20 to-10 ^o C。

2. The process of claim 1, wherein the reaction time is 4 to 10 hours.

3. The method of claim 1, wherein the molar ratio of organic ferrous iron to arylpentazole is 1:1~1:3.

4. the method of claim 1, wherein the molar ratio of total ozone to arylpentazole is 1:4~1:6.

5. the process of claim 1 wherein the reaction apparatus is at a pressure of 1 to 2 atmospheres.