CN108863847B - A kind of preparation method of perfluoronitrile compound - Google Patents

Abstract

The invention relates to the technical field of organic synthesis, in particular to a preparation method of perfluoronitrile compounds. The invention discloses a preparation method of perfluoronitrile compounds, which comprises the following steps: under the replacement protection of nitrogen or inert gas, reacting perfluoroalkene compound, metal fluoride and cyanogen chloride to obtain perfluoronitrile compound. The preparation method adopts a one-pot method to synthesize the perfluoronitrile compound, has simple operation, produces sodium chloride or potassium chloride as a byproduct of the reaction, has no pollution to the environment, and is easy to operate after treatment. In addition, the perfluoronitrile compound prepared by the preparation method has high yield, the highest yield is 82.1%, the purity is high and is higher than 99.3%, and the technical problems that the existing perfluoronitrile compound has low yield and is uneconomical are solved.

Description

A kind of preparation method of perfluoronitrile compound

technical field

The invention relates to the technical field of organic synthesis, in particular to a preparation method of perfluoronitrile compounds.

Background technique

GIS (gas-insulated switchgear) is the English abbreviation of gas-insulated fully enclosed combined electrical appliances, which is widely used in the field of high-voltage electrical appliances. SF ₆ gas is widely used in GIS because of its excellent insulation and arc extinguishing properties. However, the Global Warming Potential (GWP) of SF ₆ is about 22800 (with 100 years as the GWP assessment time, the GWP of CO ₂ is 1) (Stocker, TF; Qin, G.- KD; Plattner, M.; Tignor, SK; Allen, J.; Boschung, A.; et al. IPCC, 2013; Climate Change 2013: The PhysicalScience Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Cambridge University Press: Cambridge, United Kingdom and New York, NY, USA, 2013), so it is listed as one of the six greenhouse gases that need to be strictly controlled in the Kyoto Protocol, eventually making SF ₆ gas Widespread application in the field of high voltage substation is greatly reduced. In recent years, some well-known power companies such as ABB, 3M, etc., have carried out a lot of research to find alternative gases or mixed gases for SF ₆ , and have achieved certain results.

3M Company conducted a lot of experiments and exploratory studies, and identified two types of substitutes for SF ₆ , one of which is perfluoronitrile compounds (2,3,3,3-tetrafluoro-2-trifluoromethyl-propionitrile). ), its boiling point is -4.7°C, it can be mixed with most gases, and has the advantage of low operating temperature; in addition, its excellent insulation properties make it fully suitable for high-voltage electrical equipment GIS; finally, its GWP is only is 2210, which is much lower than that of SF ₆ gas.

However, in the existing preparation methods of perfluoronitrile compounds, the yield of perfluoronitrile compounds is low, which is uneconomical.

SUMMARY OF THE INVENTION

The invention provides a preparation method of perfluoronitrile compounds, which solves the technical problems of low yield and uneconomical performance of the existing perfluoronitrile compounds.

Its specific technical solutions are as follows:

The invention provides a preparation method of perfluoronitrile compounds, comprising the following steps:

Under the protection of nitrogen or inert gas replacement, the perfluoroalkene compound, metal fluoride and cyanogen chloride are reacted to obtain the perfluoronitrile compound.

The above protective gas is preferably nitrogen.

The device for the above reaction is a reactor, and the temperature at which the perfluoroolefin compound is charged into the reactor is -70°C to -50°C, preferably -70°C.

Preferably, the perfluoronitrile compound is perfluoroisobutyronitrile.

Preferably, the molar ratio of the perfluoroolefin compound to the cyanogen chloride is 1.5:1 to 1:1, more preferably 1.1:1;

The molar ratio of the metal fluoride to the cyanogen chloride is 1.2:1 to 1:1, more preferably 1.1:1.

Preferably, the reaction time is 3h～15h, more preferably 6h～15h, further preferably 10h;

The temperature of the reaction is 40°C to 80°C, more preferably 50°C.

Preferably, the reaction also needs to add a catalyst.

Preferably, the catalyst is a phase transfer catalyst;

The phase transfer catalyst is selected from 18-crown-6 or tetrabutylammonium chloride.

In the embodiments of the present invention, no catalyst was added in the reactions of Examples 1 to 3, and a catalyst was added in the reaction of Example 4, and the yield of perfluoroisobutyronitrile added with the catalyst was relatively high, which was 82.1%.

Preferably, the dosage of the catalyst is 0.5 mol % to 3 mol % of the dosage of the cyanogen chloride, more preferably 2 mol %.

Preferably, after the reaction is completed and before the perfluoronitrile compound is obtained, the method further includes: removing the unreacted perfluoroalkene compound, and collecting a fraction at -5°C.

Preferably, the removal of unreacted perfluoroalkene compounds is specifically: volatilizing the reaction solution after the reaction is completed at 5°C to 10°C, collecting volatile components, and placing the volatile components in- The unreacted perfluoroolefin compound is removed by volatilization at 25°C to -15°C.

In the alcohol low temperature cooling tank, the above reaction solution is cooled to 5°C to 10°C and volatilized to prevent the solvent from being carried out by the gas.

The temperature at which the volatile components were collected was -40°C.

In the embodiment of the present invention, the above-mentioned volatile components mainly include hexafluoropropylene, perfluoroisobutyronitrile, and a solvent carried out with the gas.

It should be noted that, the entire process of collecting perfluoroolefin compounds is purified according to the difference in boiling point of each substance.

Preferably, the reaction is carried out in an aprotic solvent system;

The aprotic solvent is selected from benzonitrile, acetonitrile, N,N-dimethylformamide, diethylene glycol dimethyl ether or ethylene glycol dimethyl ether, more preferably acetonitrile and diethylene glycol dimethyl ether , more preferably acetonitrile.

More preferably, the ratio of the solvent mass to the total mass of the reactants is 1.5:1 to 3:1.

Preferably, the perfluoroolefin compound is perfluoropropene.

Preferably, the metal fluoride is selected from potassium fluoride or sodium fluoride.

In the embodiment of the present invention, the specific reaction formula of perfluoronitrile compounds is as follows:

The invention provides a preparation method of perfluoronitrile compounds, comprising the following steps: reacting perfluoroalkene compounds, metal fluorides and cyanogen chloride to obtain perfluoronitrile compounds. The preparation method adopts a one-pot method to synthesize perfluoronitrile compounds, and the operation is simple, the raw material of cyanogen chloride is readily available, and the by-product of the reaction is sodium chloride or potassium chloride, which is environmentally friendly and easy to operate after post-treatment. In addition, the perfluoronitrile compounds prepared by the preparation method have high yield, the highest yield is 70.4%, and the purity is higher than 99.3%.

Detailed ways

The embodiment of the present invention provides a perfluoronitrile compound, which is used to solve the technical problems that the yield of the existing perfluoronitrile compound is low and uneconomical.

In order to make the purpose, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the embodiments described below are only a part of the implementation of the present invention. examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

Under the protection of nitrogen replacement, 12.76 g (0.22 mol) of potassium fluoride, 12.29 g (0.20 mol) of cyanogen chloride, and 100 mL of acetonitrile were added to a 500 mL dry autoclave, and 33.00 g ( 0.22mol), closed reaction at 50°C for 10 hours. After the reaction is completed, the reaction solution is volatilized at 5 °C in an alcohol low-temperature cooling tank, the volatile components are collected at -40 °C, the volatile components are volatilized at -20 °C to remove unreacted hexafluoropropylene, and then volatilized and collected to obtain the boiling point. The product perfluoroisobutyronitrile at -5°C was 27.60 g, and the yield was 70.4%.

Embodiment 2

Under the protection of nitrogen replacement, 9.24 g (0.22 mol) of sodium fluoride, 12.29 g (0.20 mol) of cyanogen chloride, and 100 mL of acetonitrile were added to a 500 mL dry autoclave, and 33.00 g ( 0.22mol), closed reaction at 50°C for 10 hours. After the reaction is completed, the reaction solution is volatilized at 5 °C in an alcohol low-temperature cooling tank, the volatile components are collected at -40 °C, the volatile components are volatilized at -20 °C to remove unreacted hexafluoropropylene, and then volatilized and collected to obtain the boiling point. It is 27.51 g of perfluoroisobutyronitrile at -5°C, and the yield is 70.2%.

Embodiment 3

Under the protection of nitrogen replacement, 12.76 g (0.22 mol) of potassium fluoride, 12.29 g (0.20 mol) of cyanogen chloride, and 100 mL of diethylene glycol dimethyl ether were added to a 500 mL dry autoclave, and slowly charged at -70°C. 33.00 g (0.22 mol) of perfluoropropene was reacted in a sealed manner at 50° C. for 10 hours. After the reaction is completed, the reaction solution is volatilized at 5°C in an alcohol low-temperature cooling tank, the volatile components are collected at -40°C, the volatile components are volatilized at -20°C to remove unreacted hexafluoropropylene, and then volatilized and collected to obtain the boiling point. It is 25.60 g of perfluoroisobutyronitrile at -5°C, and the yield is 65.3%.

Embodiment 4

Under the protection of nitrogen replacement, 12.76 g (0.22 mol) of potassium fluoride, 18-crown ether-61.056 g (4 nmol), 12.29 g (0.20 mol) of cyanogen chloride, and 100 mL of acetonitrile were added to a 500 mL dry autoclave. ~ Slowly charge 33.00 g (0.22 mol) of perfluoropropene at low temperature, and react in a closed manner at 50° C. for 5 hours. After the reaction is completed, the reaction solution is volatilized at 5 °C in an alcohol low-temperature cooling tank, the volatile components are collected at -40 °C, the volatile components are volatilized at -20 °C to remove unreacted hexafluoropropylene, and then volatilized and collected to obtain the boiling point. It is 32.18 g of perfluoroisobutyronitrile at -5°C, and the yield is 82.1%.

Embodiment 5

Under the protection of nitrogen replacement, 12.76 g (0.22 mol) of potassium fluoride, 21.18 g (0.20 mol) of cyanogen bromide, and 100 mL of acetonitrile were added to a 500 mL dry autoclave, and 33.00 g of perfluoropropene was slowly charged at -70°C to low temperature. (0.22mol), 50 ℃ closed reaction 10 hours. The reaction solution was volatilized at 5°C in an alcohol low-temperature cooling tank, the volatile components were collected at -40°C, and the volatile components were volatilized at -20°C to remove unreacted hexafluoropropene to obtain 2-bromoperfluoropropane, which could not be Perfluoroisobutyronitrile is obtained.

Embodiment 6

Example 1 to Example 4 were detected by gas chromatography.

The experimental results are shown in Table 1. The purity of the perfluoroisobutyronitrile prepared in Examples 1 to 4 of the present invention is more than 99.3%, and other components may be the solvents that are brought out. Among them, cyanogen bromide is used as the reaction raw material, Perfluoroisobutyronitrile could not be prepared because of the difference in electronegativity between cyanogen bromide and cyanogen chloride.

The purity of table 1 embodiment 1 to embodiment 5 perfluoroisobutyronitrile

purity Example 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 perfluoroisobutyronitrile 99.4% 99.5% 99.3% 99.3% none other components 0.6% 0.5% 0.7% 0.7% none

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: The technical solutions described in the embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (8)

1. a preparation method of perfluoronitrile compound, is characterized in that, comprises the following steps: Under the protection of nitrogen or inert gas replacement, the perfluoroalkene compound, metal fluoride and cyanogen chloride are reacted to obtain perfluoronitrile compound; Described metal fluoride is sodium fluoride or potassium fluoride; The perfluoroolefin compound is perfluoropropylene; The reaction time is 3h～15h; The temperature of the reaction is 40°C to 80°C. 2 . The preparation method according to claim 1 , wherein the molar ratio of the perfluoroalkene compound to the cyanogen chloride is 1.5:1 to 1:1; 2 . The molar ratio of the metal fluoride to the cyanogen chloride is 1.2:1 to 1:1. 3. preparation method according to claim 1 is characterized in that, described reaction also needs to add catalyst. 4. The preparation method according to claim 3, wherein the catalyst is a phase transfer catalyst; The phase transfer catalyst is selected from 18-crown-6 or tetrabutylammonium chloride. 5. The preparation method according to claim 3 or 4, wherein the consumption of the catalyst is 0.5 mol% to 3 mol% of the consumption of the cyanogen chloride. 6. The preparation method according to claim 1, characterized in that, after the reaction is finished, before the perfluoronitrile compound is obtained, the method further comprises: removing the unreacted perfluoroalkene compound, collecting-5 °C fraction. 7 . The preparation method according to claim 6 , wherein the removing of the unreacted perfluoroalkene compound is specifically: volatilizing the reaction solution after the reaction is completed at 5° C. to 10° C., and collecting easy Volatile components, the volatile components are volatilized at -25°C to -15°C to remove the unreacted perfluoroolefin compounds. 8. preparation method according to claim 1, is characterized in that, described reaction is carried out in aprotic solvent system; The aprotic solvent is selected from benzonitrile, acetonitrile, N,N-dimethylformamide, diethylene glycol dimethyl ether or ethylene glycol dimethyl ether.