Method for preparing trifluoroethyl trifluoromethanesulfonate

Abstract

The invention relates to a method for preparing trifluoroethyl trifluoromethanesulfonate, which comprises the following steps: (1) adding a certain amount of trifluoromethanesulfonic anhydride into a reaction kettle, slowly introducing trifluoroethanol into the reaction kettle, and reacting at room temperature for 4-8 hours; (2) carrying out reduced pressure distillation on the trifluoroethyl trifluoromethanesulfonate crude product solution, slowly raising the temperature to 50-60 DEG C, and carrying out reduced pressure distillation for 5-16 hours to obtain a trifluoroethyl trifluoromethanesulfonate refined product; the trifluoroethyl trifluoromethanesulfonate prepared by the method has high purity and high yield, and is suitable for large-scale industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis preparation, and particularly relates to a method for preparing trifluoroethyl trifluoromethanesulfonate. Background Art

[0002] Trifluoroethyl triflate is an organic compound that is commonly used as a reagent in synthetic chemistry. This compound has specific applications in organic synthesis, especially when the introduction of trifluoromethylsulfonate (-SO2CF3) is required. It can be used as an electrophilic trifluoromethylating agent to introduce trifluoromethylsulfonic acid groups into organic molecules. In the fields of medicinal chemistry, pesticide chemistry, and materials science, trifluoroethyl triflate has a wide range of application potentials as an intermediate or final product component.

[0003] Chinese patent CN117105824A provides a method for preparing trifluoroethyl trifluoromethanesulfonate, which comprises the following steps: reacting trifluoromethanesulfonic acid with trifluoroethanol to produce trifluoromethanesulfonic acid to form a fluorinated fatty amine precursor; adding a mixed solution of triethylamine and trifluoroethanol to trifluoromethanesulfonyl chloride, maintaining the reaction at a temperature below 10° C., and preparing trifluoroethyl trifluoromethanesulfonate; this method has a low conversion rate and a long purification route.

[0004] Chinese Patent CN109748831A The present invention relates to a method for preparing trifluoroethyl trifluoromethanesulfonate, which comprises the following steps: (1) synthesis: synthesizing triethylamine, trifluoroethanol and trifluoromethanesulfonyl fluoride to obtain a synthetic material; (2) hydrolysis: hydrolyzing the synthetic material; (3) rectification: sending the organic matter obtained by hydrolysis into a 300L rectification kettle, heating it with steam, and collecting the fraction with a boiling point of 89°C at the top of the tower as the target product trifluoroethyl trifluoromethanesulfonate. The advantages of the present invention are: the method for preparing trifluoroethyl trifluoromethanesulfonate of the present invention can achieve a content of more than 98% of the prepared trifluoroethyl trifluoromethanesulfonate by selecting suitable raw materials and effectively controlling the reaction conditions, and can be used for organic synthesis. The method has a hydrolysis step with a high wastewater volume, which pollutes the environment. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing trifluoroethyl trifluoromethanesulfonate, which adopts trifluoromethanesulfonic anhydride and trifluoroethanol to synthesize trifluoroethyl trifluoromethanesulfonate, and then separates it by a rectification method, and the synthesis conversion rate is high.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for preparing trifluoroethyl trifluoromethanesulfonate comprises the following steps:

[0008] (1) adding trifluoromethanesulfonic anhydride into a reaction kettle, and then starting to dropwise add trifluoroethanol, and after a certain reaction time, obtaining a crude trifluoroethyl trifluoromethanesulfonate solution;

[0009] (2) Then, the temperature is slowly raised to the temperature for vacuum distillation, and the crude trifluoroethyl trifluoromethanesulfonate solution is subjected to vacuum distillation to obtain a fine product of trifluoroethyl trifluoromethanesulfonate.

[0010] Preferably, in the step (1), the mass ratio of trifluoroethanol to trifluoromethanesulfonic anhydride is 1:1.2-2.5.

[0011] Preferably, in step (1), the reaction time is 4 to 8 hours and the reaction temperature is 20 to 30°C.

[0012] Preferably, in the step (1), the dripping time of trifluoroethanol is 2 to 8 hours.

[0013] Preferably, in the step (2), the time for slowly raising the temperature to 50-60° C. is 1-4 hours.

[0014] Preferably, in the step (2), the pressure of the vacuum distillation is -0.1 to -0.09 MPa, and the temperature of the vacuum distillation is 50 to 60°C.

[0015] Preferably, in the step (2), the time of reduced pressure distillation is 5 to 16 hours.

[0016] Principle of the present invention:

[0017] The trifluoromethanesulfonic anhydride and trifluoroethanol undergo nucleophilic substitution reaction to generate trifluoroethyl trifluoromethanesulfonate, and then the trifluoroethyl trifluoromethanesulfonate with a purity greater than 98% is obtained by rectification.

[0018] The beneficial effects of the present invention are:

[0019] The method for preparing trifluoroethyl trifluoromethanesulfonate of the present invention uses two raw materials and optimizes reaction conditions, so that the purity of the prepared trifluoroethyl trifluoromethanesulfonate is greater than 98%, and the synthesis conversion rate is greater than 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attached Figure 1 This is the H NMR spectrum of trifluoroethyl trifluoromethanesulfonate of Example 1.

[0021] Attached Figure 2 This is the NMR fluorine spectrum of trifluoroethyl trifluoromethanesulfonate in Example 1. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0023] A new method for preparing trifluoroethyl trifluoromethanesulfonate comprises the following steps: adding a certain amount of trifluoromethanesulfonic anhydride into a reaction kettle, then slowly dropping a certain amount of trifluoroethanol, and reacting for 4 to 8 hours to obtain a crude trifluoroethyl trifluoromethanesulfonate solution; slowly raising the temperature to 50 to 60° C., and performing reduced pressure distillation on the crude trifluoroethyl trifluoromethanesulfonate solution to obtain a fine product of trifluoroethyl trifluoromethanesulfonate.

[0024] Example 1

[0025] (1) Add 300 g of trifluoromethanesulfonic anhydride into a reaction kettle, then slowly drop 160 g of trifluoroethanol into the reaction kettle over a period of 2 h. The reaction is carried out at room temperature of 20° C. for 4 h.

[0026] (2) Then the temperature was slowly raised to 50°C for 4 hours, and the crude trifluoroethyl trifluoromethanesulfonate solution was subjected to vacuum distillation at a pressure of -0.09 MPa for 16 hours to obtain 222.13 g of trifluoroethyl trifluoromethanesulfonate. Figure 1 , trifluoroethyl trifluoromethanesulfonate H NMR spectrum Figure 2 .

[0027] Example 2

[0028] (1) Add 300 g of trifluoromethanesulfonic anhydride into a reaction kettle, then slowly drop 160 g of trifluoroethanol into the reaction kettle over a period of 2 h. The reaction is carried out at room temperature of 20° C. for 4 h.

[0029] (2) Then slowly raise the temperature to 60°C for 4 hours, and perform vacuum distillation on the crude trifluoroethyl trifluoromethanesulfonate solution at a pressure of -0.090 MPa for 10 hours to obtain 235.8 g of fine trifluoroethyl trifluoromethanesulfonate.

[0030] Example 3

[0031] (1) Add 300 g of trifluoromethanesulfonic anhydride into a reaction kettle, then slowly drop 120 g of trifluoroethanol into the reaction kettle over a period of 2 h. The reaction was carried out at room temperature of 30° C. for 4 h.

[0032] (2) Then slowly raise the temperature to 60° C. for 4 h, and perform vacuum distillation on the crude trifluoroethyl trifluoromethanesulfonate solution at a pressure of -0.095 MPa for 7 h to obtain 238.0 g of fine trifluoroethyl trifluoromethanesulfonate.

[0033] Example 4

[0034] (1) Add 300 g of trifluoromethanesulfonic anhydride into a reaction kettle, then slowly drop 200 g of trifluoroethanol into it. The dropwise addition time is 2 h, and the reaction is carried out at room temperature of 30° C. for 4 h.

[0035] (2) Then slowly raise the temperature to 60° C. for 4 h, and perform vacuum distillation on the crude trifluoroethyl trifluoromethanesulfonate solution at a pressure of -0.09 MPa for 10 h to obtain 241.5 g of fine trifluoroethyl trifluoromethanesulfonate.

[0036] Example 5

[0037] (1) Add 300 g of trifluoromethanesulfonic anhydride into a reaction kettle, then slowly drop 250 g of trifluoroethanol into the reaction kettle for 8 h. The reaction is carried out at room temperature of 25 °C for 8 h.

[0038] (2) Then slowly raise the temperature to 60° C. for 1 h, and perform vacuum distillation on the crude trifluoroethyl trifluoromethanesulfonate solution at a pressure of -0.1 MPa for 5 h to obtain 243 g of fine trifluoroethyl trifluoromethanesulfonate.

[0039] Table 1 Technical data of trifluoromethanesulfonic acid products obtained in different embodiments

[0040] Example purity / % Conversion rate / % Example 1 98.2 90.0 Example 2 98.1 95.5 Example 3 99.2 96.4 Example 4 98.9 97.8 Example 5 98.9 98.5

[0041] Comparative Example 1

[0042] (1) Add 300 g of trifluoromethanesulfonic anhydride into a reaction kettle, then dropwise add 160 g of trifluoroethanol into the reaction kettle over a period of 10 minutes, and react at room temperature of 20° C. for 4 hours.

[0043] (2) Then the temperature was slowly raised to 50° C. for 4 hours, and the crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation at a pressure of -0.09 MPa for 16 hours to obtain 173.26 g of trifluoroethyl trifluoromethanesulfonate with a purity of 89.3% and a yield of 70.2%.

[0044] Comparative Example 2

[0045] (1) Add 300 g of trifluoromethanesulfonic anhydride into a reaction kettle, then slowly drop 160 g of trifluoroethanol into the reaction kettle over a period of 2 h. The reaction is carried out at room temperature of 20° C. for 4 h.

[0046] (2) The temperature was then rapidly raised to 50° C. for 10 minutes, and the crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation at a pressure of −0.09 MPa for 16 hours to obtain 144.88 g of trifluoroethyl trifluoromethanesulfonate.

[0047] Purity 85.5%, yield 58.7%.

[0048] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing trifluoroethyl trifluoromethanesulfonate, characterized in that, The following steps are involved: (1) adding trifluoromethanesulfonic anhydride into a reaction kettle, and then starting to dropwise add trifluoroethanol, and after a certain reaction time, obtaining a crude trifluoroethyl trifluoromethanesulfonate solution; (2) Then, the temperature is slowly raised to the temperature for vacuum distillation, and the crude trifluoroethyl trifluoromethanesulfonate solution is subjected to vacuum distillation to obtain a fine product of trifluoroethyl trifluoromethanesulfonate.

2. A method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step (1), the mass ratio of trifluoroethanol to trifluoromethanesulfonic anhydride is 1:1.2-2.

5.

3. A method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step (1), the reaction time is 4 to 8 hours and the reaction temperature is 20 to 30°C.

4. A method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step (1), the dripping time of trifluoroethanol is 2 to 8 hours.

5. A method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step (2), the time for slowly heating to 50-60° C. is 1-4 hours.

6. A method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step (2), the pressure of the vacuum distillation is -0.1 to -0.09 MPa, and the temperature of the vacuum distillation is 50 to 60°C.

7. A method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step (2), the time of reduced pressure distillation is 5 to 16 hours.

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