Preparation method of trifluoroethyl trifluoromethanesulfonate

Abstract

The invention relates to a preparation method of trifluoroethyl trifluoromethanesulfonate, which comprises the following steps: S1, adding a certain amount of trifluoromethanesulfonic acid into a reaction kettle, then adding a certain amount of chromium-based catalyst, then controlling the temperature of the reaction kettle to 20 DEG C below zero to 10 DEG C below zero by using a low-temperature refrigerant, then slowly introducing chlorotrifluoroethane into the reaction kettle, and reacting for 4-8 hours; s2, slowly raising the temperature to 20 to 40 DEG C, and removing chlorotrifluoroethane which is not completely reacted, so as to obtain a trifluoroethyl trifluoromethanesulfonate crude product solution; s3, carrying out reduced pressure distillation on the trifluoroethyl trifluoromethanesulfonate crude product solution, and slowly raising the temperature to 60-92 DEG C 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 specifically relates to a preparation method of trifluoroethyl trifluoromethanesulfonate. Background Art

[0002] Trifluoroethyl trifluoromethanesulfonate is an important compound in organic chemistry, mainly used in the following fields: S1. In the pharmaceutical industry, it is used as an intermediate in pharmaceutical synthesis to synthesize specific drug molecules or precursors; S2. In the field of fine chemical manufacturing, it is used as a reaction auxiliary agent in the production of pesticides, fragrances, dyes and other fine chemical synthesis routes; S3. In the field of catalysis, it is combined with metal complexes to form an efficient catalyst system for various chemical reactions, such as cross-coupling reactions, cycloaddition reactions, etc.

[0003] Chinese patent CN117105824A discloses a method for preparing trifluoroethyl trifluoromethanesulfonate, and discloses a method for synthesizing trifluoroethyl trifluoromethanesulfonate, wherein triethylamine, trifluoroethanol and trifluoromethanesulfonyl chloride are synthesized to obtain a crude trifluoroethyl trifluoromethanesulfonate solution, and then water for hydrolysis is dropped into the solution, and the solution is stirred, washed with water and allowed to stand for a certain period of time to separate organic matter, and then distilled to obtain trifluoroethyl trifluoromethanesulfonate with a purity of more than 98%.

[0004] Chinese patent CN109748831A discloses a method for preparing trifluoroethyl trifluoromethanesulfonate, and discloses a method for synthesizing trifluoroethyl trifluoromethanesulfonate, wherein triethylamine, trifluoroethanol and trifluoromethanesulfonyl fluoride are synthesized to obtain a crude trifluoroethyl trifluoromethanesulfonate solution, and then water for hydrolysis is dropped into the solution, and the solution is stirred, washed with water and allowed to stand for a certain period of time to separate organic matter, and then distilled to obtain trifluoroethyl trifluoromethanesulfonate with a purity of more than 98%.

[0005] At present, there are few literatures on the synthesis of trifluoroethyl trifluoromethanesulfonate, and there are problems such as single preparation and synthesis method, low conversion rate, and long purification route. In view of this, the present invention develops a new method for synthesizing trifluoroethyl trifluoromethanesulfonate. Summary of the invention

[0006] The purpose of the present invention is to provide a preparation method of trifluoroethyl trifluoromethanesulfonate. Trifluoromethanesulfonic acid and chlorotrifluoroethane are used to synthesize trifluoroethyl trifluoromethanesulfonate. The boiling points of reactants and products are quite different, and they are easily separated by a distillation method, and the synthesis conversion rate is high.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for preparing trifluoroethyl trifluoromethanesulfonate comprises the following steps:

[0009] S1, stirring trifluoromethanesulfonic acid to make it in a flowing state, then adding a chromium-based catalyst to the flowing trifluoromethanesulfonic acid, cooling to a low temperature, and passing chlorotrifluoroethane therein to react;

[0010] S2, after the reaction is completed, the temperature is raised to a certain temperature, and the unreacted chlorotrifluoroethane is removed to obtain a crude trifluoroethyl trifluoromethanesulfonate solution;

[0011] S3. The crude trifluoroethyl trifluoromethanesulfonate solution is subjected to reduced pressure distillation to obtain a fine product of trifluoroethyl trifluoromethanesulfonate.

[0012] Preferably, in step S1, the mass ratio of trifluoromethanesulfonic acid to chlorotrifluoroethane is 1.5:1.2-2, the introduction time of chlorotrifluoroethane is 2 to 4 hours, and the reaction time is 4 to 8 hours.

[0013] Preferably, in step S1, the chromium-based catalyst is Cr 2 O 3 and CrO 3 The catalyst is used in an amount of 0.1% to 2% of the total mass of trifluoromethanesulfonic acid and chromium-based catalyst.

[0014] Preferably, in step S1, the low temperature is -20 to -10°C.

[0015] Preferably, in step S2, the temperature is raised to 20-40° C., and the time for removing unreacted chlorotrifluoroethane is 2-5 hours.

[0016] Preferably, in step S2, the heating rate is 10-30°C / h.

[0017] Preferably, in step S3, the distillation pressure is -0.1 to -0.09 MPa, and the temperature is 60 to 92°C.

[0018] Preferably, in step S3, the rate of heating during reduced pressure distillation is 5 to 30° C. / h.

[0019] Preferably, in step S1, the trifluoromethanesulfonic acid to which the chromium-based catalyst is added is cooled using either a 50% ethylene glycol solution or an ice-salt solution, and the temperature is controlled by controlling the flow rate of the ethylene glycol aqueous solution or the ice-salt solution.

[0020] Principle of the present invention:

[0021] Trifluoromethanesulfonic acid and chlorotrifluoroethane undergo electrophilic substitution reaction to generate trifluoroethyl trifluoromethanesulfonate and hydrogen chloride. The boiling point of trifluoroethyl trifluoromethanesulfonate (92° C.) is significantly different from that of hydrogen chloride (-85° C.), trifluoromethanesulfonic acid (162° C.), and chlorotrifluoroethane (7° C.). Trifluoroethyl trifluoromethanesulfonate with a purity greater than 99% can be obtained by multiple distillation methods.

[0022] The beneficial effects of the present invention are:

[0023] The synthesis method of trifluoroethyl trifluoromethanesulfonate of the present invention uses two raw materials under the action of a catalyst and optimizes the reaction conditions, so that the purity of the prepared trifluoroethyl trifluoromethanesulfonate is greater than 98%, and the synthesis conversion rate is greater than 90%. DETAILED DESCRIPTION

[0024] 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.

[0025] A new method for preparing trifluoroethyl trifluoromethanesulfonate comprises the following steps: adding a certain amount of trifluoromethanesulfonic acid into a reaction kettle, then adding a certain amount of a chromium-based catalyst, controlling the temperature of the reaction kettle to -20 to -10 DEG C using a low-temperature refrigerant, then slowly introducing chlorotrifluoroethane into the reaction kettle, and reacting for 4 to 8 hours; then slowly heating the reaction kettle to 20 to 40 DEG C, removing unreacted chlorotrifluoroethane, and obtaining a crude trifluoroethyl trifluoromethanesulfonate solution; performing reduced pressure distillation on the crude trifluoroethyl trifluoromethanesulfonate solution, and slowly increasing the temperature to 60 to 92 DEG C, and obtaining a fine product of trifluoroethyl trifluoromethanesulfonate.

[0026] Example 1

[0027] S1. Add 150 g of stirred trifluoromethanesulfonic acid into the reactor, and then add 2.68 g of catalyst Cr 2 O 3 , and then use low-temperature refrigerant (50% ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 200g of chlorotrifluoroethane into it for 3 hours. The first 2 hours are based on the speed without tail gas release, which is about 80g per hour. After 2 hours, the gas introduction speed is slowed down. After completion of the introduction, stir for 2 hours. The temperature is at -10°C, the reaction time is 5 hours, and the synthesis is completed.

[0028] S2, then slowly heating to 40°C at 17°C / h for 3h, removing unreacted chlorotrifluoroethane to obtain 229.83g crude trifluoroethyl trifluoromethanesulfonate solution;

[0029] S3. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and the temperature was slowly increased to 92° C. at 13° C. / h for 4 hours to obtain 220.30 g of trifluoroethyl trifluoromethanesulfonate.

[0030] Example 2

[0031] S1. Add 150 g of stirred trifluoromethanesulfonic acid into the reactor, and then add 2.68 g of catalyst Cr 2 O 3 , and then use low-temperature refrigerant (ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 142g of chlorotrifluoroethane into it for 3 hours. The first 2 hours are based on the speed without tail gas release, which is about 50g per hour. After 2 hours, the gas introduction speed is slowed down. After the gas is passed, stir for 2 hours. The temperature is at -10°C, the reaction time is 5 hours, and the synthesis is completed.

[0032] S2, then slowly heating to 40 ° C, the heating time is 3h, removing the unreacted chlorotrifluoroethane, and obtaining 228.59g of trifluoroethyl trifluoromethanesulfonate crude product solution;

[0033] S3. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and the temperature was slowly raised to 92° C. The heating time was 4 hours, and 221.19 g of trifluoroethyl trifluoromethanesulfonate was obtained.

[0034] Example 3

[0035] S1, add 150g of stirred trifluoromethanesulfonic acid into the reactor, and then add 2.68g of Cr 2 O 3 , and then use low-temperature refrigerant (ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 118g of chlorotrifluoroethane into it for 3 hours. The first 2 hours are based on the speed without tail gas release, which is about 50g per hour. After 2 hours, the gas introduction speed is slowed down. After the gas is passed, stir for 2 hours. The temperature is at -10°C, the reaction time is 5 hours, and the synthesis is completed.

[0036] S2, then slowly heating to 40°C for 3 hours, removing unreacted chlorotrifluoroethane to obtain 230.53 crude trifluoroethyl trifluoromethanesulfonate solution;

[0037] S3. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and the temperature was slowly raised to 92° C. The heating time was 4 hours, and 226.99 g of trifluoroethyl trifluoromethanesulfonate was obtained.

[0038] Example 4

[0039] S1, add 150g of stirred trifluoromethanesulfonic acid into the reactor, then add catalyst 1.34g Cr 2 O3 and 1.34gCrO 3 , and then use low-temperature refrigerant (ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 142g of chlorotrifluoroethane into it for 4 hours. The first 2.5 hours are based on the speed without tail gas release, which is about 50g per hour. After 2.5 hours, the gas introduction speed is slowed down. After completion of the introduction, stir for 2 hours. The temperature is at -10°C, the reaction time is 6 hours, and the synthesis is completed.

[0040] S2, then slowly heating to 40°C for 3 hours, removing unreacted chlorotrifluoroethane to obtain 230.51 crude trifluoroethyl trifluoromethanesulfonate solution;

[0041] S3. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and the temperature was slowly raised to 92° C. The heating time was 4 hours, and 220.03 g of trifluoroethyl trifluoromethanesulfonate was obtained.

[0042] Example 5

[0043] S1, add 150g of stirred trifluoromethanesulfonic acid into the reactor, then add catalyst 1.34g Cr 2 O 3 and 1.34 g CrO 3 , and then use low-temperature refrigerant (ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 142g of chlorotrifluoroethane into it for 4 hours. The first 2.5 hours are based on the speed without tail gas release, which is about 50g per hour. After 2.5 hours, the gas introduction speed is slowed down. After completion of the introduction, stir for 2 hours. The temperature is at -10°C, the reaction time is 6 hours, and the synthesis is completed.

[0044] S2, then slowly heating to 40°C for 3 hours, removing unreacted chlorotrifluoroethane to obtain 229.80 crude trifluoroethyl trifluoromethanesulfonate solution;

[0045] S3. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and the temperature was slowly raised to 85° C. The heating time was 3.5 h, and 205.64 g of trifluoroethyl trifluoromethanesulfonate was obtained.

[0046] Example 6

[0047] S1, add 150g of stirred trifluoromethanesulfonic acid into the reactor, then add catalyst 0.67g Cr 2 O 3 and 0.67 g CrO 3, and then use low-temperature refrigerant (ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 142g of chlorotrifluoroethane into it for 4 hours. The first 2.5 hours are based on a speed without tail gas release, which is about 50g per hour. After 2.5 hours, the gas introduction speed is slowed down. After completion of the introduction, stir for 2 hours. The temperature is at -10°C, the reaction time is 6 hours, and the synthesis is completed.

[0048] S2, then slowly heating to 40°C for 3 hours, removing unreacted chlorotrifluoroethane to obtain 225.80 crude trifluoroethyl trifluoromethanesulfonate solution;

[0049] S3. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and the temperature was slowly raised to 92° C. The heating time was 4 hours, and 167.80 g of trifluoroethyl trifluoromethanesulfonate was obtained.

[0050] Comparative Example 1

[0051] S1. Add 150 g of stirred trifluoromethanesulfonic acid into the reactor, and then add 2.68 g of catalyst Cr 2 O 3 , and then use low-temperature refrigerant (ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 142g of chlorotrifluoroethane into it for 3 hours. The first 2 hours are based on the speed without tail gas release, which is about 50g per hour. After 2 hours, the gas introduction speed is slowed down. After the gas is passed, stir for 2 hours. The temperature is at -10°C, and the synthesis is completed.

[0052] S2, then quickly heating to 40°C for 1 hour to remove unreacted chlorotrifluoroethane to obtain 223.41 crude trifluoroethyl trifluoromethanesulfonate solution;

[0053] S3. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and then the temperature was rapidly raised to 92° C. The heating time was 1.5 h, and 200.53 g of trifluoroethyl trifluoromethanesulfonate was obtained.

[0054] Comparative Example 2

[0055] S1. Add 150g of trifluoromethanesulfonic acid into the reactor, and then add 2.68g of catalyst Cr 2 O 3 , and then use low-temperature refrigerant (ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 142g of chlorotrifluoroethane into it for 3 hours. The first 2 hours are based on the speed without tail gas release, which is about 50g per hour. After 2 hours, the gas introduction speed is slowed down. After the gas is passed, there is no stirring reaction for 2 hours. The temperature is at -10°C, and the synthesis is completed.

[0056] S2, then slowly raise the temperature to 40°C for 3 hours, remove the unreacted chlorotrifluoroethane, and obtain 225.8 g crude trifluoroethyl trifluoromethanesulfonate solution;

[0057] S3. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and the temperature was slowly raised to 92° C. The heating time was 4 hours, and 135.6 g of trifluoroethyl trifluoromethanesulfonate was obtained.

[0058] Comparative Example 3

[0059] S1. Add 213g of trifluoromethanesulfonic acid into the reactor, and then add 2.68g of catalyst Cr 2 O 3 , and then use low-temperature refrigerant (ethylene glycol solution) to control the temperature of the reactor to -20°C, and then slowly pass 142g of chlorotrifluoroethane into it for 3 hours. The first 2 hours are based on a speed without tail gas release, which is about 50g per hour. After 2 hours, the gas introduction speed is slowed down. After the gas is passed, stir the reaction for 2 hours. The temperature is at -10°C, and the synthesis is completed.

[0060] S2. The crude trifluoroethyl trifluoromethanesulfonate solution was subjected to reduced pressure distillation, and the temperature was slowly raised to 92° C. The heating time was 4 hours, and 176.24 g of trifluoroethyl trifluoromethanesulfonate was obtained.

[0061] Table 1 Technical data of trifluoromethanesulfonic acid products obtained in different embodiments

[0062]

[0063] 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 content of the present invention.

Claims

1. A method for preparing trifluoroethyl trifluoromethanesulfonate, characterized in that: The following steps are involved: S1, stirring trifluoromethanesulfonic acid to make it in a flowing state, then adding a chromium-based catalyst to the flowing trifluoromethanesulfonic acid, cooling to a low temperature, and passing chlorotrifluoroethane therein to react; S2, after the reaction is completed, the temperature is raised to a certain temperature, and the unreacted chlorotrifluoroethane is removed to obtain a crude trifluoroethyl trifluoromethanesulfonate solution; S3. The crude trifluoroethyl trifluoromethanesulfonate solution is subjected to reduced pressure distillation to obtain a fine product of trifluoroethyl trifluoromethanesulfonate.

2. The method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, wherein: In the step S1, the mass ratio of trifluoromethanesulfonic acid to chlorotrifluoroethane is 1.5:1.2-2, the chlorotrifluoroethane is introduced for 2 to 4 hours, and the reaction time is 4 to 8 hours.

3. The method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, wherein: In the step S1, the chromium-based catalyst is one of Cr2O3 and CrO3 or a mixture of the two, and the amount of the catalyst accounts for 0.1% to 2% of the total mass of trifluoromethanesulfonic acid and the chromium-based catalyst.

4. The method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, wherein: In the step S1, the low temperature is -20 to -10°C.

5. The method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step S2, the temperature is raised to 20-40° C., and the time for removing unreacted chlorotrifluoroethane is 2-5 hours.

6. The method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step S2, the heating rate is 10-30°C / h.

7. The method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step S3, the distillation pressure is -0.1 to -0.09 MPa and the temperature is 60 to 92°C.

8. The method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, wherein: In the step S3, the rate of temperature increase during reduced pressure distillation is 5 to 30°C / h.

9. The method for preparing trifluoroethyl trifluoromethanesulfonate according to claim 1, characterized in that: In the step S1, the trifluoromethanesulfonic acid to which the chromium-based catalyst is added is cooled using either a 50% ethylene glycol solution or ice-salt water, and the temperature is controlled by controlling the flow rate of the ethylene glycol solution or the ice-salt water.

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