阅读说明：本技术 一种七氟异丁腈的制备方法 (Preparation method of heptafluoroisobutyronitrile ) 是由 李丽 唐念 周永言 张曼君 黎晓淀 樊小鹏 于 2019-10-14 设计创作，主要内容包括：本申请属于无机化学的技术领域,尤其涉及一种七氟异丁腈的制备方法。本申请提供了一种七氟异丁腈的制备方法,包括以下步骤：步骤1、在有机溶剂和碱液存在的条件下,七氟异丁酰胺与对甲苯磺酰氯进行缩合,获得对甲苯磺酸七氟异丁酰酯；步骤2、所述对甲苯磺酸七氟异丁酰酯在-30～20℃的温度条件下反应,产生七氟异丁腈和对甲苯磺酸盐。本申请公开了一种七氟异丁腈的制备方法,能有效解决目前制备七氟异丁腈的方法存在的收率低、成本高、且难以储存在体系的技术缺陷。(The application belongs to the technical field of inorganic chemistry, and particularly relates to a preparation method of heptafluoroisobutyronitrile. The application provides a preparation method of heptafluoroisobutyronitrile, which comprises the following steps: step 1, condensing heptafluoro isobutyramide and p-toluenesulfonyl chloride in the presence of an organic solvent and an alkali liquor to obtain p-toluenesulfonic acid heptafluoro isobutyryl ester; and 2, reacting the p-toluenesulfonic acid heptafluoroisobutyryl ester at the temperature of-30-20 ℃ to generate heptafluoroisobutyronitrile and p-toluenesulfonic acid salt. The application discloses a preparation method of heptafluoroisobutyronitrile, which can effectively overcome the technical defects of low yield, high cost and difficulty in storage in a system in the conventional method for preparing heptafluoroisobutyronitrile.)

1. The preparation method of heptafluoroisobutyronitrile is characterized by comprising the following steps:

step 1, condensing heptafluoro isobutyramide and p-toluenesulfonyl chloride in the presence of an organic solvent and an alkali liquor to obtain p-toluenesulfonic acid heptafluoro isobutyryl ester;

and 2, reacting the p-toluenesulfonic acid heptafluoroisobutyryl ester at the temperature of-30-20 ℃ to generate heptafluoroisobutyronitrile and p-toluenesulfonic acid ester.

2. The method according to claim 1, wherein the organic solvent is one or more selected from the group consisting of ether solvents, ester solvents, aromatic solvents, and halogenated hydrocarbon solvents.

3. The method according to claim 1, wherein the organic solvent is one or more selected from the group consisting of methyl t-butyl ether, tetrahydrofuran, ethyl acetate, ethyl propionate, toluene, xylene, methylene chloride, and dichloroethane.

4. The method according to claim 1, wherein the lye is selected from the group consisting of linear amines and/or cyclic amines.

5. The method of claim 1, wherein the alkali solution is one or more selected from triethylamine, diethylamine, isopropylamine, cyclohexylamine and aniline.

6. The method according to claim 1, wherein the molar ratio of heptafluoroisobutyramide to p-toluenesulfonyl chloride is 1: (1-2.5).

7. The method according to claim 1, wherein the molar ratio of heptafluoroisobutyramide to p-toluenesulfonyl chloride is 1: (1.1-1.5).

8. The method according to claim 1, wherein the molar ratio of the lye to the heptafluoroisobutyramide is (1-2.5): 1.

9. the method according to claim 1, wherein the molar ratio of the lye to the heptafluoroisobutyramide is (1.1-1.5): 1.

10. the method according to claim 1, wherein the reaction time in step 2 is 2 to 4 hours.

Technical Field

The application belongs to the technical field of inorganic chemistry, and particularly relates to a preparation method of heptafluoroisobutyronitrile.

Background

With the continuous development and innovation of global energy internet, Gas Insulated Switchgear (GIS) and gas insulated transmission line (GIL) are widely used in power grids. SF as GIS and GIL internal insulation medium₆It is considered to be a nearly ideal insulating gas due to its excellent insulating and arc extinguishing properties and low liquefaction temperature. However, SF₆Is a strong greenhouse effect gas with a potential greenhouse effect (GWP) of about CO₂23500 times of the total gas life, about 3200 a. Thus, SF was developed₆Displacing gas is an imminent task.

Heptafluoroisobutyronitrile (C)₄F₇N) is a potential insulating gas with a gas GWP of 2400 and approximately SF₆1/10 (A) has low toxicity, excellent chemical stability, Ozone Depletion Potential (ODP) of 0, life of about 22a in the atmosphere, and dielectric strength of about SF at one atmospheric pressure₆2 times of the total weight of the powder.

Heptafluoroisobutyronitrile (C) as presently disclosed₄F₇N) there are two preparation routes:

the first preparation route takes nitrogen-containing heterocycle as a starting material, and generates heptafluoroisobutyronitrile after the nitrogen-containing heterocycle is subjected to ring opening by means of high energy such as illumination or thermal cracking. The document J.CHEM.SOC.PERKIN TRANS.1,1990:983-987 reports a method for synthesizing heptafluoroisobutyronitrile by using a photochemical method and a fluoro-1, 2, 3-triazine compound as a raw material, wherein the reaction equation is

However, the method has the disadvantages of high cost of raw materials, low reaction yield and harsh reaction conditions, and is not suitable for industrial application.

In another preparation route, hexafluoropropylene is used as a raw material to prepare heptafluoroisobutyronitrile. PCT patent application WO2013151471 discloses a preparation method of heptafluoroisobutyronitrile, which comprises the steps of firstly carrying out addition reaction on hexafluoropropylene and carbonyl fluoride to obtain perfluoroisobutyryl fluoride, then carrying out reaction on the perfluoroisobutyryl fluoride and ammonia gas to obtain perfluoroisobutyramide, and finally dehydrating the perfluoroisobutyramide to obtain the heptafluoroisobutyronitrile, wherein the reaction formula is

In the step of preparing heptafluoroisobutyronitrile by dehydrating perfluoroisobutyramide in the method, if a common dehydrating agent is used, the yield is low, the cost for treating three wastes is high, and if an expensive dehydrating agent is used, the problem of low yield can be solved, but the cost is too high, so that the industrial amplification is not facilitated.

Both of the above-disclosed processes are difficult to control the process, and heptafluoronitrile cannot be temporarily present in the system, so that further improvement of the process for producing heptafluoroisobutyronitrile is required. However, the research on the heptafluoroisobutyronitrile gas in China is relatively late, for C₄F₇N preparation technology is less published and reported. Thus, the novel and effective methods for preparing C₄F₇N, promoting the domestic formation of the preparation technology is a difficult problem to be solved urgently.

Disclosure of Invention

In view of this, the present application discloses a method for preparing heptafluoroisobutyronitrile, which can effectively overcome the technical defects of low yield, high cost and difficulty in storage in a system in the existing method for preparing heptafluoroisobutyronitrile.

The application provides a preparation method of heptafluoroisobutyronitrile, which is characterized by comprising the following steps:

step 1, condensing heptafluoro isobutyramide and p-toluenesulfonyl chloride in the presence of an organic solvent and an alkali liquor to obtain p-toluenesulfonic acid heptafluoro isobutyryl ester;

and 2, reacting the p-toluenesulfonic acid heptafluoroisobutyryl ester at the temperature of-30-20 ℃ to generate heptafluoroisobutyronitrile and p-toluenesulfonic acid salt.

The preparation route of the heptafluoroisobutyronitrile is as follows:

preferably, the organic solvent is selected from one or more of an ether solvent, an ester solvent, an aromatic solvent and a halogenated hydrocarbon solvent.

Preferably, the organic solvent is selected from the group consisting of methyl tert-butyl ether, tetrahydrofuran, ethyl acetate, ethyl propionate, toluene, xylene, dichloromethane, dichloroethane.

Preferably, the lye is selected from linear amines or/and cyclic amines.

Preferably, the alkali liquor is selected from one or more of triethylamine, diethylamine, isopropylamine, cyclohexylamine and aniline.

Preferably, the molar ratio of the heptafluoroisobutyramide to the p-toluenesulfonyl chloride is 1: (1-2.5).

More preferably, the molar ratio of the heptafluoroisobutyramide to the p-toluenesulfonyl chloride is 1: (1.1-1.5).

Preferably, the molar ratio of the alkali liquor to the heptafluoroisobutyramide is (1-2.5): 1.

more preferably, the molar ratio of the alkali liquor to the heptafluoroisobutyramide is (1.1-1.5): 1.

preferably, in step 2, the reaction time is 2-4 h.

The p-toluenesulfonate in the product of the step 2 can be removed by methods such as purification or separation, and the high-purity heptafluoroisobutyronitrile is obtained.

The invention discloses a novel preparation method of heptafluoroisobutyronitrile, which comprises the steps of condensing p-toluenesulfonyl chloride and heptafluoroisobutyramide in an organic solvent in the presence of alkali, and obtaining products of heptafluoroisobutyronitrile and p-toluenesulfonate with different compositions through the change of temperature. The whole process has mild conditions, is easy to operate and is suitable for industrial amplification.

Compared with the prior art, the invention has the following advantages:

(1) mixtures of heptafluoroisobutyronitrile and p-toluenesulfonic acid heptafluoroisobutyryl ester with different proportions can be prepared according to requirements; (2) three wastes are basically not generated, the solvent is recycled, and the byproduct is sold as a commodity; (3) the reaction condition is mild.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 is a graph showing the content change of tosylate and the target product, heptafluoroisobutyronitrile, in examples 1 to 6 of the present application.

Detailed Description

The application provides a preparation method of heptafluoroisobutyronitrile, which is used for solving the technical defects of low yield, high cost and difficulty in storage in a system in the method for preparing heptafluoroisobutyronitrile in the prior art.

The technical solutions in the embodiments of the present application will be described clearly and completely below, and it should be understood that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The raw materials used in the following examples are all commercially available or self-made.