Synthesis method of nonafluoroisobutyl methyl ether

Abstract

The invention discloses a synthesis method of nonafluoroisobutyl methyl ether, which comprises the following steps: by taking hexafluoropropylene oxide and fluoromethane as raw materials, enabling fluorine to be bionic into nucleophilic trifluoromethyl negative ions (CF3-) under an alkaline condition, and in the presence of an amide compound, enabling the CF3-to attack amide carbonyl carbon to form oxygen negative ions (CF3CR (H) NR1R2O-), then, the intermediate attacks carbon with high electrophilicity in hexafluoropropylene oxide, hexafluoropropylene oxide is subjected to a ring-opening reaction, perfluoroisobutyryl fluoride is generated, and a part of sub-amide is generated; then, acyl fluoride is subjected to nucleophilic addition and methylation through fluorine ions, and finally synthesis of the nonafluoroisobutyl methyl ether is completed. The method realizes resource utilization of the fluorine imitation waste, and has the advantages of high conversion efficiency, mild reaction conditions and simple operation flow.

Description

Technical Field

[0001] This invention relates to the field of fluorine chemical synthesis technology, specifically to a method for synthesizing nonafluoroisobutyl methyl ether. Background Technology

[0002] As the global electronics industry moves towards higher integration and miniaturization, precision cleaning technology has become a core requirement in high-tech fields such as semiconductor manufacturing. Traditional chlorofluorocarbon (CFC) cleaning agents are gradually being restricted by regulations due to their high ozone depletion potential (ODP) and significant global warming potential (GWP). In contrast, nonafluoroisobutyl methyl ether (NBE) has become an ideal solvent to replace HCFCs due to its chemical inertness, zero ozone depletion, low boiling point, low viscosity, and low surface tension. This material not only performs excellently in applications such as semiconductor wafer and precision instrument cleaning, optical component decontamination, and solvent dilution, but also fully complies with international environmental regulations such as EU REACH and US EPA SNAP, providing key technological support for promoting the green upgrading of the electronics manufacturing industry.

[0003] Several methods for preparing nonafluoroisobutyl methyl ether have been reported both domestically and internationally, mainly falling into three technical routes: electrolysis, addition, and pyrolysis. Chinese patent CN101541723A discloses an electrolytic method involving the electrolysis of n-butyryl chloride in the presence of hydrofluoric acid to generate perfluoroisobutyryl fluoride and perfluorobutyryl fluoride, which are then etherified with a methylating agent to obtain the target product. While this route has low raw material costs, it is difficult to industrialize due to high technical barriers in electrolysis, yields that are difficult to exceed 40%, difficulties in tail gas recovery, high electrode plate costs, and numerous impurities.

[0004] Chinese patent CN110433743A discloses a method for preparing perfluoroisobutyryl fluoride by introducing gaseous raw materials hexafluoropropylene and carbonyl fluoride, and introducing a liquid solvent containing a catalyst (DMF) into the liquid feed inlet; the catalyst is KF; and setting the reaction temperature in the reactor to 75-85 °C. The perfluoroisobutyryl fluoride is then etherified. This method has a short route, few steps, high atom economy, and excellent synthesis efficiency. However, carbonyl fluoride is highly reactive, toxic, hazardous, and expensive.

[0005] Chinese patent CN117567252A discloses a method for preparing perfluoroisobutyl ether via phase transfer catalysis of hexafluoropropylene dimer. Specifically, the method involves: S1 catalytic reaction of hexafluoropropylene to prepare hexafluoropropylene dimer; S2 activation followed by oxidative cracking of the hexafluoropropylene dimer to prepare perfluoroisobutyryl fluoride and perfluoroacetyl fluoride; and S3 etherification of the perfluoroisobutyryl fluoride to obtain perfluoroisobutyl ether. While the above cracking method has advantages such as mild reaction conditions, high yield, no pollution, and easy scalability, it suffers from low atom economy, and the intermediates are prone to further cracking, leading to a decrease in atom utilization.

[0006] Fluoroform (CF3H) is a potent greenhouse gas and is typically found as a byproduct of the polytetrafluoroethylene (PTFE) industry. Although fluoroform contains a trifluoromethyl functional group, its strong CF bond and unstable CF3 bond make it a significant greenhouse gas. - Currently, fluoroform is typically incinerated rather than utilized as a raw material for CF3H. Therefore, how to achieve the resource utilization of CF3H and develop a low-cost, safe, and environmentally friendly preparation technology for nonafluoroisobutyl methyl ether remains a significant challenge for professionals in the industry. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for synthesizing nonafluoroisobutyl methyl ether. Using hexafluoropropylene oxide and fluoroform as raw materials, perfluoroisobutyryl fluoride is synthesized, and then efficiently converted to nonafluoroisobutyl methyl ether via an etherification reaction. This method achieves the resource utilization of fluoroform waste and features high conversion efficiency, mild reaction conditions, and a simple operating procedure.

[0008] A method for synthesizing nonafluoroisobutyl methyl ether includes the following steps: (1) Fluoroform is passed into a compound containing an alkali and an amide (i.e., R). 1 R 2 In the reaction system of NCR(H)O, hexafluoropropylene oxide is then introduced into the reaction system to synthesize perfluoroisobutyryl fluoride; (2) Under the action of alkali metal fluoride (i.e. MF), the perfluoroisobutyryl fluoride obtained in step (1) and the alkylating agent (i.e. CH3X) are reacted in an organic solvent to prepare nonafluoroisobutyl methyl ether.

[0009] The specific reaction route is as follows: In this invention, under alkaline conditions, fluoroform generates a nucleophilic trifluoromethyl anion (CF3). - ), CF3 - Attacking the carbonyl carbon of the amide to form an oxygen anion (CF3CR(H)NR) 1 R 2 O - Subsequently, this intermediate attacks the more electrophilic carbon in hexafluoropropylene oxide, causing the hexafluoropropylene oxide to undergo a ring-opening reaction, generating the perfluoroisobutyroxene anion intermediate ((CF3)2CFCF2O). - The intermediate readily eliminates a molecule of fluoride salt to generate perfluoroisobutyryl fluoride and a molecule of amide. The fluoride ions provided by the alkali metal fluoride attack the carbonyl carbon of the perfluoroisobutyryl fluoride to form a fluoroalcohol anion intermediate. The oxygen atom in the fluoroalcohol anion combines with the methyl group in the methylating agent to obtain nonafluoroisobutyl methyl ether.

[0010] This invention uses hexafluoropropylene oxide and fluoroform as raw materials to synthesize perfluoroisobutyryl fluoride, and achieves efficient conversion through an etherification reaction to generate nonafluoroisobutyl methyl ether. This method realizes the resource utilization of fluoroform waste and features high conversion efficiency, mild reaction conditions, and a simple operation process.

[0011] Preferably, in step (1), the molar ratio of fluoroform to hexafluoropropylene oxide is 1~20:1.

[0012] Preferably, in step (1), the base is one or more of potassium tert-butoxide, tetramethylammonium fluoride, tetrabutylammonium fluoride, sodium ethoxide, sodium methoxide, sodium trifluoroethoxide, sodium isopropoxide, and tri(trimethylsilyl)amine; and the amide compound is one of N,N-dimethylformamide, N-formylmorpholine, 1,3-dimethylimidazolinone, and N,N-dimethylpropenylurea.

[0013] Preferably, in step (1), the molar ratio of the alkali, amide compound and hexafluoropropylene oxide is 0.1~3:0.1~3:1.

[0014] Preferably, in step (1), the reaction temperature is -40~200 ℃ and the reaction time is 1~24 h.

[0015] Preferably, in step (2), the alkali metal fluoride is one of sodium fluoride, potassium fluoride, rubidium fluoride, and cesium fluoride.

[0016] Preferably, in step (2), the alkylating agent is one of dimethyl sulfate, dimethyl carbonate, iodomethane, and methyl p-toluenesulfonate.

[0017] Preferably, in step (2), the molar ratio of the alkylating agent to perfluoroisobutyryl fluoride is 1~5:1~5.

[0018] Preferably, in step (2), the organic solvent is one of tetrahydrofuran, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetonitrile, diisopropyl ether, dibutyl ether, and tert-butyl methyl ether.

[0019] More preferably, the alkylating agent is dimethyl sulfate or dimethyl carbonate, and the organic solvent is diethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether.

[0020] Preferably, in step (2), the reaction temperature is -20~150 ℃ and the reaction time is 1~48 h.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses a method for synthesizing nonafluoroisobutyl methyl ether, using hexafluoropropylene oxide and fluoroform as raw materials, and under alkaline conditions, generating a nucleophilic trifluoromethyl anion (CF3). - In the presence of amide compounds, CF3 - Attacking the carbonyl carbon of the amide to form an oxygen anion (CF3CR(H)NR) 1 R 2 O - The intermediate then attacks the more electrophilic carbon in hexafluoropropylene oxide, causing a ring-opening reaction to produce perfluoroisobutyryl fluoride and a molecular amide. Subsequently, nucleophilic addition of fluoride ions to the acyl fluoride leads to methylation, ultimately synthesizing nonafluoroisobutyl methyl ether. This method achieves the resource utilization of fluoroform waste, featuring high conversion efficiency, mild reaction conditions, and a simple operating procedure. Attached Figure Description

[0022] Figure 1 This is the mass spectrum of the nonafluoroisobutyl methyl ether prepared in Example 1. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited to the following embodiments.

[0024] All raw materials used in this invention are commercially available.

[0025] Example 1 (1) Synthesis of perfluoroisobutyryl fluoride Take a 500 mL reactor and add anhydrous N,N-dimethylformamide (6.6 g, 90 mmol), tris(trimethylsilyl)amine (7.0 g, 30 mmol), dehydrated tetramethylammonium fluoride (2.8 g, 30 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). Fluoroform (5.1 g, 150 mmol) is passed into the solution, and the reaction temperature is maintained at -20 °C. When the pressure inside the reactor stabilizes, hexafluoropropylene oxide (5.0 g, 30 mmol) is introduced, and the reaction temperature is maintained at -20 °C while stirring. The tail gas from the reactor is monitored by gas chromatography until the hexafluoropropylene oxide has completely reacted, and the temperature is raised to room temperature. Then, the gas outlet valve of the reactor is opened, and the gas is passed into a dry ice-cooled collection bottle; the uncooled gas is collected in a steel cylinder. After the reaction was completed, perfluoroisobutyryl fluoride (4.05 g, 18.7 mmol) was obtained by distillation, with a yield of 62.5%.

[0026] (2) Synthesis of nonafluoroisobutyl methyl ether A 500 mL reactor was used to sequentially add potassium fluoride (2.1 g, 36 mmol), dimethyl sulfate (4.5 g, 36 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). The reactor temperature was lowered to -20 °C. Perfluoroisobutyryl fluoride (6.5 g, 30 mmol) was slowly added dropwise, and the reaction was stirred at -20 °C for 1 hour. The temperature was then slowly raised to 50 °C, and the reaction was continued with stirring for 6 hours until the pressure inside the reactor stabilized. After the reaction was complete, the reaction mixture was washed with water, separated into layers, and the organic phase was collected and distilled to obtain pure nonafluoroisobutyl methyl ether (6.4 g, 25.6 mmol), with a yield of 85.3%. Its mass spectra are shown below. Figure 1 As shown, GC-MS (EI) m / z 231 [MF] + ,219[(CF3)2CFCF2] + 169 [C3F7] + 150 [(CF3)2C] + 100[CF3CF] + 81 [CF2OCH3] + 69 [CF3] + Because the molecular ion peak of this compound is unstable, no molecular ion peak was detected. Meanwhile, [OCH3]... + Because the ion peak intensity was too low, it was not displayed on the mass spectrum. A literature review revealed that the ion fragment peaks of the publicly reported nonafluoroisobutyl methyl ether were highly consistent with the experimentally obtained mass spectrum; therefore, the compound was confirmed to be nonafluoroisobutyl methyl ether.

[0027] Example 2 (1) Preparation of perfluoroisobutyryl fluoride Take a 500 mL reactor and add anhydrous N,N-dimethylformamide (6.6 g, 90 mmol), tris(trimethylsilyl)amine (7.0 g, 30 mmol), dehydrated tetramethylammonium fluoride (2.8 g, 30 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). Fluoroform (5.1 g, 150 mmol) is passed into the solution, and the reaction temperature is maintained at -30 °C. When the pressure inside the reactor stabilizes, hexafluoropropylene oxide (5.0 g, 30 mmol) is introduced, and the reaction temperature is maintained at -30 °C while stirring. The tail gas from the reactor is monitored by gas chromatography until the hexafluoropropylene oxide has completely reacted, and the temperature is raised to room temperature. Then, the gas outlet valve of the reactor is opened, and the gas is passed into a dry ice-cooled collection bottle; the uncooled gas is collected in a steel cylinder. After the reaction was completed, perfluoroisobutyryl fluoride (3.6 g, 16.7 mmol) was obtained by distillation, with a yield of 55.6%.

[0028] (2) Synthesis of nonafluoroisobutyl methyl ether A 500 mL reactor was used to sequentially add potassium fluoride (2.1 g, 36 mmol), dimethyl sulfate (4.5 g, 36 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). The reactor temperature was lowered to -20 °C. Perfluoroisobutyryl fluoride (6.5 g, 30 mmol) was slowly added dropwise, and the reaction was stirred at -20 °C for 1 hour. Subsequently, the temperature was slowly raised to 50 °C, and the reaction was continued with stirring for 6 hours until the pressure inside the reactor remained stable. After the reaction was completed, the reaction mixture was washed with water, separated into layers, and the organic phase was collected and distilled to obtain pure nonafluoroisobutyl methyl ether (6.4 g, 25.6 mmol), with a yield of 85.3%.

[0029] Example 3 (1) Preparation of perfluoroisobutyryl fluoride Take a 500 mL reactor and add anhydrous N,N-dimethylformamide (6.6 g, 90 mmol), tris(trimethylsilyl)amine (7.0 g, 30 mmol), dehydrated tetramethylammonium fluoride (2.8 g, 30 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). Fluoroform (5.1 g, 150 mmol) is passed into the solution, and the reaction temperature is maintained at 0 °C. When the pressure inside the reactor stabilizes, hexafluoropropylene oxide (5.0 g, 30 mmol) is introduced, and the reaction temperature is maintained at 0 °C while stirring. The tail gas from the reactor is monitored by gas chromatography until the hexafluoropropylene oxide has completely reacted, and the temperature is raised to room temperature. Then, the gas outlet valve of the reactor is opened, and the gas is passed into a dry ice-cooled collection bottle; the uncooled gas is collected in a steel cylinder. After the reaction was completed, perfluoroisobutyryl fluoride (3.3 g, 15.3 mmol) was obtained by distillation, with a yield of 51.3%.

[0030] (2) Synthesis of nonafluoroisobutyl methyl ether A 500 mL reactor was used to sequentially add potassium fluoride (2.1 g, 36 mmol), dimethyl sulfate (4.5 g, 36 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). The reactor temperature was lowered to -20 °C. Perfluoroisobutyryl fluoride (6.5 g, 30 mmol) was slowly added dropwise, and the reaction was stirred at -20 °C for 1 hour. Subsequently, the temperature was slowly raised to 50 °C, and the reaction was continued with stirring for 6 hours until the pressure inside the reactor remained stable. After the reaction was completed, the reaction mixture was washed with water, separated into layers, and the organic phase was collected and distilled to obtain pure nonafluoroisobutyl methyl ether (6.4 g, 25.6 mmol), with a yield of 85.3%.

[0031] Example 4 (1) Preparation of perfluoroisobutyryl fluoride Take a 500 mL reactor and add anhydrous N,N-dimethylformamide (6.6 g, 90 mmol), tris(trimethylsilyl)amine (7.0 g, 30 mmol), dehydrated tetramethylammonium fluoride (2.8 g, 30 mmol), and anhydrous acetonitrile (100 mL). Fluoroform (5.1 g, 150 mmol) is passed into the solution, and the reaction temperature is maintained at -20 °C. When the pressure inside the reactor stabilizes, hexafluoropropylene oxide (5.0 g, 30 mmol) is introduced, and the reaction temperature is maintained at -20 °C while stirring. The tail gas from the reactor is monitored by gas chromatography until the hexafluoropropylene oxide has completely reacted, and then the temperature is raised to room temperature. Subsequently, the gas outlet valve of the reactor is opened, and the gas is passed into a dry ice-cooled collection bottle; the uncooled gas is collected in a steel cylinder. After the reaction was completed, perfluoroisobutyryl fluoride (3.7 g, 17.1 mmol) was obtained by distillation, with a yield of 57.1%.

[0032] (2) Synthesis of nonafluoroisobutyl methyl ether A 500 mL reactor was used to sequentially add potassium fluoride (2.1 g, 36 mmol), dimethyl sulfate (4.5 g, 36 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). The reactor temperature was lowered to -20 °C. Perfluoroisobutyryl fluoride (6.5 g, 30 mmol) was slowly added dropwise, and the reaction was stirred at -20 °C for 1 hour. Subsequently, the temperature was slowly raised to 50 °C, and the reaction was continued with stirring for 6 hours until the pressure inside the reactor remained stable. After the reaction was completed, the reaction mixture was washed with water, separated into layers, and the organic phase was collected and distilled to obtain pure nonafluoroisobutyl methyl ether (6.4 g, 25.6 mmol), with a yield of 85.3%.

[0033] Example 5 (1) Preparation of perfluoroisobutyryl fluoride Take a 500 mL reactor and add anhydrous N,N-dimethylformamide (6.6 g, 90 mmol), tris(trimethylsilyl)amine (10.5 g, 45 mmol), dehydrated tetramethylammonium fluoride (4.2 g, 45 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). Fluoroform (5.1 g, 150 mmol) is passed into the solution, and the reaction temperature is maintained at -20°C. When the pressure inside the reactor stabilizes, hexafluoropropylene oxide (5.0 g, 30 mmol) is introduced, and the reaction temperature is maintained at -20°C while stirring. The tail gas from the reactor is monitored by gas chromatography until the hexafluoropropylene oxide has completely reacted, and the temperature is raised to room temperature. Then, the gas outlet valve of the reactor is opened, and the gas is passed into a dry ice-cooled collection bottle; the uncooled gas is collected in a steel cylinder. After the reaction was completed, perfluoroisobutyryl fluoride (4.2 g, 19.4 mmol) was obtained by distillation, with a yield of 65.3%.

[0034] (2) Synthesis of nonafluoroisobutyl methyl ether A 500 mL reactor was used to sequentially add potassium fluoride (2.1 g, 36 mmol), dimethyl sulfate (4.5 g, 36 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). The reactor temperature was lowered to -20 °C. Perfluoroisobutyryl fluoride (6.5 g, 30 mmol) was slowly added dropwise, and the reaction was stirred at -20 °C for 1 hour. Subsequently, the temperature was slowly raised to 50 °C, and the reaction was continued with stirring for 6 hours until the pressure inside the reactor remained stable. After the reaction was completed, the reaction mixture was washed with water, separated into layers, and the organic phase was collected and distilled to obtain pure nonafluoroisobutyl methyl ether (6.4 g, 25.6 mmol), with a yield of 85.3%.

[0035] Example 6 (1) Preparation of perfluoroisobutyryl fluoride Take a 500 mL reactor and add anhydrous N,N-dimethylformamide (6.6 g, 90 mmol), tris(trimethylsilyl)amine (10.5 g, 45 mmol), dehydrated tetramethylammonium fluoride (4.2 g, 45 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). Fluoroform (5.1 g, 150 mmol) is passed into the solution, and the reaction temperature is maintained at -20°C. When the pressure inside the reactor stabilizes, hexafluoropropylene oxide (5.0 g, 30 mmol) is introduced, and the reaction temperature is maintained at -20°C while stirring. The tail gas from the reactor is monitored by gas chromatography until the hexafluoropropylene oxide has completely reacted, and the temperature is raised to room temperature. Then, the gas outlet valve of the reactor is opened, and the gas is passed into a dry ice-cooled collection bottle; the uncooled gas is collected in a steel cylinder. After the reaction was completed, perfluoroisobutyryl fluoride (4.2 g, 19.4 mmol) was obtained by distillation, with a yield of 65.3%.

[0036] (2) Synthesis of nonafluoroisobutyl methyl ether A 500 mL reactor was used to sequentially add potassium fluoride (2.1 g, 36 mmol), dimethyl sulfate (4.5 g, 36 mmol), and anhydrous diethylene glycol dimethyl ether (100 mL). The reactor temperature was lowered to -20 °C. Perfluoroisobutyryl fluoride (6.5 g, 30 mmol) was slowly added dropwise, and the reaction was stirred at -20 °C for 1 hour. Subsequently, the temperature was slowly raised to 50 °C, and the reaction was continued with stirring for 6 hours until the pressure inside the reactor remained stable. After the reaction was completed, the reaction mixture was washed with water, separated into layers, and the organic phase was collected and distilled to obtain pure nonafluoroisobutyl methyl ether (6.2 g, 24.8 mmol), with a yield of 82.5%.

[0037] Example 7 (1) Preparation of perfluoroisobutyryl fluoride Take a 500 mL reactor and add anhydrous N,N-dimethylformamide (6.6 g, 90 mmol), tris(trimethylsilyl)amine (10.5 g, 45 mmol), dehydrated tetramethylammonium fluoride (4.2 g, 45 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). Fluoroform (5.1 g, 150 mmol) is passed into the solution, and the reaction temperature is maintained at -20°C. When the pressure inside the reactor stabilizes, hexafluoropropylene oxide (5.0 g, 30 mmol) is introduced, and the reaction temperature is maintained at -20°C while stirring. The tail gas from the reactor is monitored by gas chromatography until the hexafluoropropylene oxide has completely reacted, and the temperature is raised to room temperature. Then, the gas outlet valve of the reactor is opened, and the gas is passed into a dry ice-cooled collection bottle; the uncooled gas is collected in a steel cylinder. After the reaction was completed, perfluoroisobutyryl fluoride (4.2 g, 19.4 mmol) was obtained by distillation, with a yield of 65.3%.

[0038] (2) Synthesis of nonafluoroisobutyl methyl ether A 500 mL reactor was used to sequentially add potassium fluoride (2.1 g, 36 mmol), dimethyl carbonate (3.2 g, 36 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). The reactor temperature was lowered to -20 °C. Perfluoroisobutyryl fluoride (6.5 g, 30 mmol) was slowly added dropwise, and the reaction was stirred at -20 °C for 1 hour. Subsequently, the temperature was slowly raised to 50 °C, and the reaction was continued with stirring for 6 hours until the pressure inside the reactor remained stable. After the reaction was completed, the reaction mixture was washed with water, separated into layers, and the organic phase was collected and distilled to obtain pure nonafluoroisobutyl methyl ether (5.7 g, 22.8 mmol), with a yield of 76.3%.

[0039] Example 8 (1) Preparation of perfluoroisobutyryl fluoride Take a 500 mL reactor and add anhydrous N,N-dimethylformamide (6.6 g, 90 mmol), tris(trimethylsilyl)amine (10.5 g, 45 mmol), dehydrated tetramethylammonium fluoride (4.2 g, 45 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL). Fluoroform (5.1 g, 150 mmol) is passed into the solution, and the reaction temperature is maintained at -20°C. When the pressure inside the reactor stabilizes, hexafluoropropylene oxide (5.0 g, 30 mmol) is introduced, and the reaction temperature is maintained at -20°C while stirring. The tail gas from the reactor is monitored by gas chromatography until the hexafluoropropylene oxide has completely reacted, and the temperature is raised to room temperature. Then, the gas outlet valve of the reactor is opened, and the gas is passed into a dry ice-cooled collection bottle; the uncooled gas is collected in a steel cylinder. After the reaction was completed, perfluoroisobutyryl fluoride (4.2 g, 19.4 mmol) was obtained by distillation, with a yield of 65.3%.

[0040] (2) Synthesis of nonafluoroisobutyl methyl ether In a 500 mL reactor, cesium fluoride (5.5 g, 36 mmol), dimethyl sulfate (3.2 g, 36 mmol), and anhydrous tetraethylene glycol dimethyl ether (100 mL) were added sequentially, and the reactor temperature was lowered to -20 °C. Perfluoroisobutyryl fluoride (6.5 g, 30 mmol) was slowly added dropwise, and the reaction was stirred at -20 °C for 1 hour. The temperature was then slowly raised to 50 °C, and the reaction was continued with stirring for 5 hours until the pressure inside the reactor stabilized. After the reaction was complete, the reaction mixture was washed with water, separated into layers, and the organic phase was collected and distilled to obtain pure nonafluoroisobutyl methyl ether (6.6 g, 26.4 mmol), with a yield of 87.6%.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for synthesizing nonafluoroisobutyl methyl ether, characterized in that, Includes the following steps: (1) Fluoroform is introduced into a reaction system containing alkali and amide compounds, and then hexafluoropropylene oxide is introduced into the reaction system to synthesize perfluoroisobutyryl fluoride; (2) Under the action of alkali metal fluoride, the perfluoroisobutyryl fluoride obtained in step (1) and the alkylating agent are reacted in an organic solvent to prepare nonafluoroisobutyl methyl ether.

2. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 1, characterized in that, In step (1), the molar ratio of fluoroform to hexafluoropropylene oxide is 1~20:

1.

3. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 1, characterized in that, In step (1), the base is one or more of potassium tert-butoxide, tetramethylammonium fluoride, tetrabutylammonium fluoride, sodium ethoxide, sodium methoxide, sodium trifluoroethoxide, sodium isopropoxide, and tri(trimethylsilyl)amine; the amide compound is one of N,N-dimethylformamide, N-formylmorpholine, 1,3-dimethylimidazolinone, and N,N-dimethylpropenylurea.

4. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 1, characterized in that, In step (1), the molar ratio of the alkali, amide compound and hexafluoropropylene oxide is 0.1~3:0.1~3:

1.

5. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 1, characterized in that, In step (2), the alkali metal fluoride is one of sodium fluoride, potassium fluoride, rubidium fluoride, and cesium fluoride.

6. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 1, characterized in that, In step (2), the alkylating agent is one of dimethyl sulfate, dimethyl carbonate, iodomethane, and methyl p-toluenesulfonate.

7. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 1, characterized in that, In step (2), the molar ratio of the alkylating agent to perfluoroisobutyryl fluoride is 1~5:1~5.

8. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 1, characterized in that, In step (2), the organic solvent is one of tetrahydrofuran, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetonitrile, diisopropyl ether, dibutyl ether, and tert-butyl methyl ether.

9. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 6 or 8, characterized in that, The alkylating agent is dimethyl sulfate or dimethyl carbonate, and the organic solvent is diethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether.

10. The method for synthesizing nonafluoroisobutyl methyl ether according to claim 1, characterized in that, In step (1), the reaction temperature is -40~200 ℃ and the reaction time is 1~24 h; in step (2), the reaction temperature is -20~150 ℃ and the reaction time is 1~48 h.

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