Synthesis method of 3-ethoxy-2, 4-trifluoromethyl perfluoropentane

Abstract

The invention belongs to the field of fluorine chemical industry, and particularly relates to a synthesis method of 3-ethoxy-2, 4-trifluoromethyl perfluoropentane, which specifically comprises the following steps: in the presence of a solvent and a phase transfer catalyst, in a dry reaction kettle, perfluorobutyryl fluoride and carbonate form a stable intermediate, and the stable intermediate and an alkylation reagent R-C2H5 are subjected to an alkylation reaction to obtain 3-ethoxy-2, 4-trifluoromethyl perfluoropentane. The product 3-ethoxy-2, 4-trifluoromethyl perfluoropentane is obtained after the reaction is completed. According to the method disclosed by the invention, the commercial alkali carbonate is adopted as a reactant, and the yield can reach 85% by optimizing the synthesis conditions, so that the yield is greatly improved; the reaction speed is high, the reaction time is short, and complete conversion can be realized within 24 hours; meanwhile, the raw materials are easier to obtain and high in utilization rate, and industrial production is easier to realize.

Description

Technical Field

[0001] The invention belongs to the field of fluorine chemical industry, and particularly relates to a method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane. Background Art

[0002] 3-Ethoxy-2,4-trifluoromethylperfluoropentane is a non-flammable fluid with an extremely low global warming potential (GWP = 100). Its excellent inertness and dielectric properties make it an ideal replacement for high-GWP fluids such as PFCs (perfluorocarbons) and PFPEs (perfluoropolyethers) in a variety of applications. 3-Ethoxy-2,4-trifluoromethylperfluoropentane engineered fluid is used as a heat transfer fluid for cooling reactors in the pharmaceutical and chemical processing industries. In the semiconductor industry, it is an ideal choice for automated test equipment (ATE) and wafer handling equipment requiring extremely low temperatures. 3-Ethoxy-2,4-trifluoromethylperfluoropentane is also used as an automated cascade refrigerant.

[0003] The currently disclosed synthesis route for 3-ethoxy-2,4-trifluoromethylperfluoropentane is based on 3M's patent US20080139683A1 (corresponding Chinese patent CN101541723A). It uses 1,1,1,2,4,5,5,5-octafluoro-2,4-bis(trifluoromethyl)-3-pentanone as the starting material, which reacts with diethyl sulfate in the presence of an alkali metal and a phase transfer catalyst to produce 3-ethoxy-2,4-trifluoromethylpentane. However, this synthesis process suffers from a low yield of only 6.1%. Furthermore, the reaction cycle is very long, requiring over 89 hours, resulting in very low production efficiency. Therefore, optimization of this process is urgently needed to meet the requirements of industrial production. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane.

[0005] To achieve the above object, the technical solution adopted by the present invention is: A method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane is prepared using the following formula (I): (I).

[0006] Specifically, the method includes the following steps: in the presence of a solvent and a phase transfer catalyst, in a dry reactor, perfluorobutyryl fluoride (molecular formula (CF3)2CFCOF, the same below) and carbonate form a stable intermediate, and then undergo an alkylation reaction with an alkylating agent R-C2H5 to obtain the product 3-ethoxy-2,4-trifluoromethylperfluoropentane.

[0007] The molar ratio of perfluorobutyryl fluoride to carbonate is 1:0.5-5; preferably 1:1; preferably, the carbonate is an alkali metal carbonate, more preferably one or more combinations of cesium carbonate, sodium carbonate, and potassium carbonate.

[0008] The molar ratio of the perfluorobutyryl fluoride to the phase transfer catalyst is 1:0.01~1, preferably 1:0.1; the phase transfer catalyst is selected from one or more combinations of tetrabutylammonium bromide, 12-crown-4, 15-crown-5, and 18-crown-6.

[0009] The molar ratio of perfluorobutyryl fluoride to the alkylating agent is 1:0.5-5. Preferably, the molar ratio of perfluorobutyryl fluoride to the alkylating agent is 1:0.5-1; the alkylating agent is one or more combinations of iodine, diethyl sulfate, and diethyl carbonate.

[0010] The solvent is selected from one or more combinations of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

[0011] The synthesis method of 3-ethoxy-2,4-trifluoromethylperfluoropentane specifically comprises the following steps: adding a solvent, a phase transfer catalyst, and an alkali carbonate into a dry reactor, then adding perfluorobutyryl fluoride into the reactor, maintaining the temperature of the reactor at -10°C to 70°C, and starting stirring; after 1-4 hours, adding an alkylating agent into the reactor to carry out an alkylation reaction to obtain a product.

[0012] The reactor temperature is preferably maintained at 10°C to 40°C or below, more preferably 20°C to 40°C or below. The alkylation reaction time is 1 to 24 hours, preferably 20 hours.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane. The method uses commercial alkali metal carbonate as a reactant. By optimizing the synthesis conditions, the yield can reach 85%, which is a significant improvement. The method also has a fast reaction speed and a short reaction time, and can achieve complete conversion within 24 hours. Furthermore, the raw materials are more readily available and have a high utilization rate, making industrial production more readily possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a chromatogram of 3-ethoxy-2,4-trifluoromethylperfluoropentane; Figure 2 This is the mass spectrum of 3-ethoxy-2,4-trifluoromethylperfluoropentane. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and the best embodiments.

[0016] Example 1: A method for synthesizing ethoxy-2,4-trifluoromethylperfluoropentane, comprising the following steps: adding ethylene glycol dimethyl ether (180.0 g, 2 mol), tetrabutylammonium bromide (32.2 g, 0.1 mol), and sodium carbonate (106.0 g, 1 mol) as a solvent to a dry reactor, then adding perfluorobutyryl fluoride (216.0 g, 1 mol) to the reactor, maintaining the reactor temperature at 20°C with stirring; after 4 hours, adding iodine ethane (156.0 g, 1 mol) to the reactor, and terminating the reaction after 20 hours. The liquid phase was collected by filtration, allowed to stand for decomposition, and the lower liquid phase was collected and distilled to obtain 131.1 g of the target product, 3-ethoxy-2,4-trifluoromethylperfluoropentane. Figure 1 、 2 The chromatogram and mass spectrum are shown respectively, and the yield is about 63%.

[0017] Example 2: A method for synthesizing ethoxy-2,4-trifluoromethylperfluoropentane comprises the following steps: adding tetraethylene glycol dimethyl ether (222.1 g, 1 mol), 15-crown ether-5 (22.0 g, 0.1 mol), and cesium carbonate (163.0 g, 0.5 mol) to a dry reactor, then adding perfluorobutyryl fluoride (216.0 g, 1 mol) to the reactor, maintaining the reactor temperature at 10°C with stirring; after 4 hours, adding diethyl sulfate (77.0 g, 0.5 mol) to the reactor, and completing the reaction after 20 hours. The liquid phase was collected by filtration, allowed to stand for separation, and the lower liquid phase was collected and distilled to obtain 147.7 g of the target product, 3-ethoxy-2,4-trifluoromethylperfluoropentane, with a yield of approximately 70%.

[0018] Example 3: A method for synthesizing ethoxy-2,4-trifluoromethylperfluoropentane comprises the following steps: adding diethylene glycol dimethyl ether (402.0 g, 3 mol), 18-crown ether-6 (26.4 g, 0.1 mol), and potassium carbonate (138.0 g, 1 mol) to a dry reactor, then adding perfluorobutyryl fluoride (216.0 g, 1 mol) to the reactor, maintaining the reactor temperature at 40°C with stirring; after 4 hours, adding diethyl carbonate (118.0 g, 1 mol) to the reactor, and terminating the reaction after 20 hours. The liquid phase is collected by filtration, allowed to stand for separation, and the lower liquid phase is collected and distilled to obtain 166.6 g of the target product, 3-ethoxy-2,4-trifluoromethylperfluoropentane, in a yield of approximately 80%.

[0019] Example 4: A method for synthesizing ethoxy-2,4-trifluoromethylperfluoropentane comprises the following steps: adding diethylene glycol dimethyl ether (402.0 g, 3 mol), 18-crown ether-6 (26.4 g, 0.1 mol), and potassium carbonate (138.0 g, 1 mol) to a dry reactor, then adding perfluorobutyryl fluoride (216.0 g, 1 mol) to the reactor, maintaining the reactor temperature at 20°C with stirring; after 4 hours, adding diethyl carbonate (118.0 g, 1 mol) to the reactor, and terminating the reaction after 20 hours. The liquid phase is collected by filtration, allowed to stand for separation, and the lower liquid phase is collected and distilled to obtain 177.0 g of the target product, 3-ethoxy-2,4-trifluoromethylperfluoropentane, in a yield of approximately 85%.

[0020] Example 5: A method for synthesizing ethoxy-2,4-trifluoromethylperfluoropentane comprises the following steps: adding diethylene glycol dimethyl ether (402.0 g, 3 mol), 18-crown 6 (26.4 g, 0.1 mol), potassium carbonate (138.0 g, 1 mol), perfluorobutyryl fluoride (216.0 g, 1 mol), and diethyl carbonate (118.0 g, 1 mol) to a dry reactor all at once, maintaining the reactor temperature at 40°C with stirring. After 24 hours, the reaction is completed. The liquid phase is collected by filtration, allowed to stand for separation, and the lower liquid phase is collected and distilled to obtain 89.5 g of the target product, 3-ethoxy-2,4-trifluoromethylperfluoropentane, in a yield of approximately 43%.

[0021] Comparative Example 1: (Patent US2008139683A1 / CN101541723A) Preparation of ethoxy-2,4-trifluoromethylperfluoropentane, specifically comprising the following steps: adding 302 g (0.83 mol) of a mixture of 96.0% (CF3)2CFC(O)CF(CF3)2[1,1,1,2,4,5,5,5-octafluoro-2,4-bis(trifluoromethyl)-3-pentanone] and 4.0% CF3CF2CF2C(O)CF(CF3)2[1,1,1,2,4,4,5,5,6,6,6-undecafluoro-2-trifluoromethyl-3-hexanone] perfluoroheptanone, 300 mL of anhydrous ethylene glycol dimethyl ether, 59.5 g (1.02 mol) of potassium fluoride, and 11.1 g of methyltrialkylammonium chloride (Adogen™) into a 2 L flask. 464) phase transfer catalyst and 174g (1.12mol) diethyl sulfate were added and heated to 52°C with stirring for 89 hours. At the end of 89 hours, the flask was cooled to room temperature and 230g of 45% potassium hydroxide solution and 95g of water were added. The resulting mixture was subjected to azeotropic distillation using a Dean Stark water trap, and the lower fluorinated compound was separated during the distillation. The fluorinated compound phase was washed twice with equal volumes of water and dried over magnesium sulfate. 53.0g of the product (CF3)2CFCF(OC2H5)CF(CF3)2[ethoxy-2,4-trifluoromethylperfluoropentane] was obtained with a purity of 37.6% (yield 6.1%, structure confirmed by GCMS).

[0022] From the above comparison, it can be seen that the yield of the preparation method of ethoxy-2,4-trifluoromethyl perfluoropentane provided in Comparative Example 1 is 6.1%; the yield of preparing ethoxy-2,4-trifluoromethyl perfluoropentane by the method provided in Example 4 of the present invention can reach 85%, which is a significant improvement in yield; in addition, the reaction time in Comparative Example 1 is 89 hours, while the reaction time of the present invention can be completed within 24 hours, with a fast reaction speed and a short reaction time, which is suitable for industrial production; in addition, the raw material potassium fluoride used in Comparative Example 1 and the raw material potassium carbonate used in Example 4 of the present invention are cheap and easier to obtain, which are suitable for industrial production. Therefore, the preparation method of ethoxy-2,4-trifluoromethyl perfluoropentane of the present invention has a higher yield, a faster reaction rate, and a lower cost, which can meet the needs of industrial production.

[0023] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane, characterized in that: The following formula (I) is used for preparation: （I）。 2. The method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane according to claim 1, characterized in that: The method specifically includes the following steps: in the presence of a solvent and a phase transfer catalyst, in a dry reactor, perfluorobutyryl fluoride and carbonate form a stable intermediate, and then undergo an alkylation reaction with an alkylating agent R-C2H5 to obtain the product 3-ethoxy-2,4-trifluoromethylperfluoropentane.

3. The method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane according to claim 2, characterized in that: The molar ratio of the perfluorobutyryl fluoride to the carbonate is 1:0.5-5; and the carbonate is an alkali metal carbonate.

4. The method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane according to claim 2, characterized in that: The molar ratio of the perfluorobutyryl fluoride to the phase transfer catalyst is 1:0.01-1, and the phase transfer catalyst is one or more combinations of tetrabutylammonium bromide, 12-crown-4, 15-crown-5, and 18-crown-6.

5. The method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane according to claim 2, characterized in that: The molar ratio of perfluorobutyryl fluoride to the alkylating agent is 1:0.5-5, and the alkylating agent R-C2H5 is one or more combinations of iodine, diethyl sulfate, and diethyl carbonate.

6. The method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane according to claim 2, characterized in that: The solvent is one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether.

7. The method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane according to claim 2, characterized in that: The method specifically comprises the following steps: adding a solvent, a phase transfer catalyst, and a carbonate into a dry reactor, then adding perfluorobutyryl fluoride into the reactor, maintaining the temperature of the reactor at -10°C to 70°C, and starting stirring; after 1-4 hours, adding an alkylating agent into the reactor to carry out an alkylation reaction to obtain a product.

8. The method for synthesizing 3-ethoxy-2,4-trifluoromethylperfluoropentane according to claim 7, characterized in that: The alkylation reaction temperature is -10°C to 70°C, and the alkylation reaction time is 1 to 24 hours.

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