A method for preparing trifluoroethyl triflate

Abstract

The application relates to a preparation method of trifluoroethyl triflate, which comprises the following steps: S1, a certain amount of trifluoromethanesulfonic acid is added into a reaction kettle, then a certain amount of a chromium-based catalyst is added, low-temperature refrigerant is used to control the temperature of the reaction kettle to be-20 to-10 DEG C, then chlorotrifluoroethane is slowly introduced into the reaction kettle, and the reaction time is 4 to 8 hours; S2, then the temperature is slowly increased to 20 to 40 DEG C, the unreacted chlorotrifluoroethane is removed, and a trifluoroethyl triflate crude product solution is obtained; S3, the trifluoroethyl triflate crude product solution is subjected to vacuum distillation, the temperature is slowly increased to 60 to 92 DEG C, and the trifluoroethyl triflate fine product is obtained; the trifluoroethyl triflate prepared by the application 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 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, which comprises synthesizing trifluoroethyl trifluoromethanesulfonate by reacting triethylamine, trifluoroethanol and trifluoromethanesulfonyl chloride to obtain a crude trifluoroethyl trifluoromethanesulfonate solution, then dripping hydrolysis water into the solution, stirring, washing with water and allowing the solution to stand for a certain period of time to separate organic matter, and then rectifying to obtain trifluoroethyl trifluoromethanesulfonate with a purity of more than 98%.

[0004] Chinese patent CN109748831A discloses a method for preparing trifluoroethyl trifluoromethanesulfonate, which comprises synthesizing trifluoroethyl trifluoromethanesulfonate by reacting triethylamine, trifluoroethanol and trifluoromethanesulfonyl fluoride to obtain a crude trifluoroethyl trifluoromethanesulfonate solution, then dripping hydrolysis water into the solution, stirring, washing with water and allowing the solution to stand for a certain period of time to separate organic matter, and then rectifying to obtain trifluoroethyl trifluoromethanesulfonate with a purity of more than 98%.

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

[0006] The present invention aims to provide a method for preparing trifluoroethyl trifluoromethanesulfonate. The method adopts trifluoromethanesulfonic acid and chlorotrifluoroethane to synthesize trifluoroethyl trifluoromethanesulfonate. The boiling points of reactants and products differ greatly, and the reactants and products 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 thereinto to react;

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

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

[0012] Preferably, in 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.

[0013] Preferably, in 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.

[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 ice brine, and the temperature is controlled by controlling the flow rate of the ethylene glycol solution or ice brine.

[0020] Principle of the present invention:

[0021] Trifluoromethanesulfonic acid and chlorotrifluoroethane undergo an 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 through 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°C using a low-temperature refrigerant, then slowly introducing chlorotrifluoroethane into the reaction kettle for a reaction time of 4 to 8 hours; then slowly heating the reaction kettle to 20 to 40°C, removing unreacted chlorotrifluoroethane, and obtaining a crude trifluoroethyl trifluoromethanesulfonate solution; and subjecting the crude trifluoroethyl trifluoromethanesulfonate solution to reduced pressure distillation, and slowly increasing the temperature to 60 to 92°C to obtain a refined trifluoroethyl trifluoromethanesulfonate solution.

[0026] Example 1

[0027] S1, in reactor, add the trifluoromethanesulfonic acid of the stirring of 150g, then add 2.68g catalyst Cr2O3, use low-temperature refrigerant (50% ethylene glycol solution) control reactor temperature to-20 ℃, then slowly the chlorotrifluoroethane of 200g is passed wherein, the time is 3h, first 2h is as the criterion with the speed that does not emit tail gas, and per hour is about 80g, and the gas velocity that passes into slows down after 2h, and passes into rear stirring 2h, temperature is at-10 ℃, and reaction times 5h, synthesis finishes.

[0028] S2, then slowly heating to 40°C at 17°C / h for 3 hours to remove unreacted chlorotrifluoroethane to obtain 229.83g of a 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, in reactor, add the trifluoromethanesulfonic acid of the stirring of 150g, then add 2.68g catalyst Cr2O3, use low-temperature refrigerant (ethylene glycol solution) control reactor temperature to-20 ℃, then slowly the chlorotrifluoroethane of 142g is passed wherein, the time is 3h, first 2h is as the criterion with the speed of emitting without tail gas, per hour is about 50g, passes into gas velocity after 2h and slows down, and passes into rear stirring 2h, temperature is at-10 ℃, and reaction times 5h, synthesis finishes.

[0032] S2, then slowly heating to 40 ° C, heating time is 3h, removing unreacted chlorotrifluoroethane, to obtain 228.59g 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. for 4 hours to obtain 221.19 g of fine trifluoroethyl trifluoromethanesulfonate.

[0034] Example 3

[0035] S1, in reactor, add the trifluoromethanesulfonic acid of the stirring of 150g, then add catalyzer 2.68g Cr o , use low-temperature refrigerant (ethylene glycol solution) control reactor temperature to-20 ℃, then slowly the chlorotrifluoroethane of 118g is passed wherein, the time is 3h, and preceding 2h is as the criterion with the speed of emitting without tail gas, and per hour is about 50g, and feeding gas velocity slows down after 2h, and passes into rear stirring 2h, temperature is at-10 ℃, and reaction times 5h, synthetic finishes.

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

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

[0038] Example 4

[0039] S1, in reactor, add the trifluoromethanesulfonic acid that 150g stirs, then add catalyzer 1.34g Cr O And 1.34gCrO , use cryogenic refrigerant (ethylene glycol solution) control reactor temperature to-20 ℃ again, then slowly the chlorotrifluoroethane of 142g is passed wherein, the time is 4h, first 2.5h is as the criterion with the speed of emitting without tail gas, and per hour is about 50g, and feeding gas velocity slows down after 2.5h, and passing into rear stirring 2h, temperature is at-10 ℃, and reaction times 6h, synthetic finishes.

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

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

[0042] Example 5

[0043] S1, the trifluoromethanesulfonic acid that adds the stirring of 150g in reactor, then add catalyzer 1.34g Cr O And 1.34g CrO , use cryogenic refrigerant (ethylene glycol solution) control reactor temperature to-20 ℃ again, then slowly the chlorotrifluoroethane of 142g is passed wherein, the time is 4h, first 2.5h is as the criterion with the speed that does not emit with tail gas, and per hour is about 50g, and feeding gas velocity slows down after 2.5h, and passes into rear stirring 2h, temperature is at-10 ℃, and reaction times 6h, synthetic finishes.

[0044] S2, then slowly heating to 40 ° C, heating time is 3h, 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. for 3.5 h to obtain 205.64 g of trifluoroethyl trifluoromethanesulfonate.

[0046] Example 6

[0047] S1, the trifluoromethanesulfonic acid that adds the stirring of 150g in reactor, then add catalyzer 0.67g Cr O And 0.67g CrO , use cryogenic refrigerant (ethylene glycol solution) control reactor temperature to-20 ℃ again, then slowly the chlorotrifluoroethane of 142g is passed wherein, the time is 4h, first 2.5h is as the criterion with the speed that does not emit with tail gas, per hour is about 50g, passes into gas velocity behind the 2.5h and slows down, and passes into rear stirring 2h, temperature is at-10 ℃, and reaction times 6h, synthetic finishes.

[0048] S2, then slowly heating to 40 ° C, heating time is 3h, 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. for 4 hours to obtain 167.80 g of trifluoroethyl trifluoromethanesulfonate.

[0050] Comparative Example 1

[0051] S1, in reactor, add the trifluoromethanesulfonic acid of the stirring of 150g, then add 2.68g catalyst Cr2O3, use low-temperature refrigerant (ethylene glycol solution) control reactor temperature to-20 ℃, then slowly the chlorotrifluoroethane of 142g is passed wherein, the time is 3h, and first 2h is as the criterion with the speed that does not emit tail gas, and per hour is about 50g, and feeding gas velocity slows down after 2h, and passes into rear stirring 2h, and temperature is at-10 ℃, and synthesis finishes.

[0052] S2, then quickly heating to 40 ° C, heating time is 1 hour, removing unreacted chlorotrifluoroethane, to obtain 223.41 trifluoroethyl trifluoromethanesulfonate crude product solution;

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

[0054] Comparative Example 2

[0055] S1, in reactor, add the trifluoromethanesulfonic acid of 150g, then add 2.68g catalyst Cr2O3, control reactor temperature to-20 ℃ with low-temperature refrigerant (ethylene glycol solution), then slowly 142g chlorotrifluoroethane is passed wherein, time is 3h, first 2h is as the criterion with the speed that no tail gas emits, and per hour is about 50g, and the gas velocity that passes into slows down after 2h, and passes into rear no stirring reaction 2h, temperature is at-10 ℃, and synthesis finishes.

[0056] S2, then slowly heating to 40 ° C, heating time is 3 hours, removing unreacted chlorotrifluoroethane, to obtain 225.8 g trifluoroethyl trifluoromethanesulfonate crude product solution;

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

[0058] Comparative Example 3

[0059] S1, in reactor, add the trifluoromethanesulfonic acid of 213g, then add 2.68g catalyst Cr2O3, control reactor temperature to-20 ℃ with low-temperature refrigerant (ethylene glycol solution), then slowly 142g chlorotrifluoroethane is passed wherein, time is 3h, first 2h is as the criterion with the speed that does not emit tail gas, and per hour is about 50g, and the gas velocity that passes into slows down after 2h, and passes into rear stirring reaction 2h, and temperature is at-10 ℃, and synthesis finishes.

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

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

[0062]

[0063] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above 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. Stir trifluoromethanesulfonic acid to make it flow, then add a chromium-based catalyst to the flowing trifluoromethanesulfonic acid, cool it to -20~-10°C, and pass chlorotrifluoroethane into it to react; 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; 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; 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 brine, and the temperature is controlled by controlling the flow rate of the ethylene glycol solution or ice brine; S2, after the reaction is completed, the temperature is raised to a certain temperature, and unreacted chlorotrifluoroethane is removed to obtain a crude trifluoroethyl trifluoromethanesulfonate solution; In step S2, the temperature is raised to 20-40° C., and the time for removing unreacted chlorotrifluoroethane is 2-5 hours; In step S2, the heating rate is 10-30°C / h; S3, performing reduced pressure distillation on the crude trifluoroethyl trifluoromethanesulfonate solution to obtain a refined trifluoroethyl trifluoromethanesulfonate; In step S3, the distillation pressure is -0.1 to -0.09 MPa and the temperature is 60 to 92°C; In the step S3, the rate of heating during the reduced pressure distillation is 5-30°C / h.

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