A method and system for semi-continuous preparation of trifluoromethyl trifluoromethanesulfonate

Abstract

The invention discloses a method for preparing trifluoromethyl trifluoromethanesulfonate semi-continuously, which comprises the following steps: S1, in a reactor A, phosphorus pentoxide and trifluoromethanesulfonic acid are added in sequence, and distilled after stirring; S2, the condensate during distillation is a crude trifluoromethanesulfonic anhydride, which is collected in a reactor B; trifluoromethanesulfonic acid is added dropwise to the reactor B for reflux reaction; S3, the condensation of the reflux is stopped, the gas phase of the reactor B is condensed to form a condensate and collected in a gas-liquid separation tank, gas-liquid separation is performed, and the separated liquid enters a distillation tower for distillation; S4, the fraction trifluoromethyl trifluoromethanesulfonate is collected at the top of the tower. The invention also provides a system for preparing trifluoromethyl trifluoromethanesulfonate semi-continuously, and the reaction conditions of the invention are relatively mild, the process is simple, the reaction yield is high, and it is easy to realize large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and specifically relates to a method for semi-continuously preparing trifluoromethyl trifluoromethanesulfonate. Background Art

[0002] Trifluoromethyl trifluoromethanesulfonate (CF3SO2OCF3, TFMT) is a colorless liquid with a boiling point of 21°C. It is relatively volatile and has high thermal stability. CF3SO2OCF3 is an important fluoroalkylation reagent, which was previously mainly used in nucleophilic trifluoromethoxylation reactions. There are few reports on its application in other areas.

[0003] This product is widely used in nucleophilic trifluoromethoxylation reactions to synthesize functional molecules containing trifluoromethoxy groups. It is an important organic intermediate and pharmaceutical intermediate for trifluoroformylation and nucleophilic fluorination. The currently reported synthesis methods of trifluoromethyl trifluoromethanesulfonate include: using trifluoromethanesulfonic acid and fluorosulfonic acid to carry out a cyclic reflux contact reaction at a temperature that vaporizes trifluoromethanesulfonic acid to prepare trifluoromethyl trifluoromethanesulfonate, but due to the instability of fluorosulfonic acid, the reaction yield is very low and the industrial manufacturing cost is high; in addition, it is reported that trifluoromethyl trifluoromethanesulfonate can be prepared by reacting trifluoroiodomethane and silver trifluoromethanesulfonate in an organic solvent; the raw materials of this method are not easy to obtain, and solvents are required, which produces more three wastes and is not conducive to industrial production. Summary of the invention

[0004] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a semi-continuous method for preparing trifluoromethyl trifluoromethanesulfonate with relatively mild reaction conditions, simple process and high reaction yield.

[0005] The technical solution adopted by the present invention is:

[0006] The present invention discloses a method for semi-continuously preparing trifluoromethyl trifluoromethanesulfonate, which comprises the following steps:

[0007] S1. In reactor A, add phosphorus pentoxide and trifluoromethanesulfonic acid in sequence to form a solid-liquid reaction mixture, stir and react at 50°C-70°C for 16 hours, and then distill reactor A;

[0008] The condensate during S2 and distillation is a crude trifluoromethanesulfonic anhydride product, which is collected in a reactor B; trifluoromethanesulfonic acid is added dropwise to the above-mentioned reactor B, and then refluxed under stirring;

[0009] S3, stop the reflux condensation, condense the gas phase of reactor B to form condensate and collect it in a gas-liquid separation tank, and pump the collected liquid into a distillation tower for distillation;

[0010] S4, the distillation tower kettle pressure is 0.08MPa-0.1MPa, and the kettle temperature is 50℃-78℃.

[0011] Furthermore, in step S1, the molar ratio of trifluoromethanesulfonic acid to phosphorus pentoxide is 4:1-5:1; the purity of the trifluoromethanesulfonic acid is ≥99.0%, the content of fluoride ions in the trifluoromethanesulfonic acid is ≤10ppm, and the content of sulfate ions is ≤50ppm; and the stirring rate is 35HZ-50HZ.

[0012] Furthermore, in step S1, the distillation temperature is 85°C-95°C, and the condensation temperature is 7°C.

[0013] Furthermore, in step S2, the reflux heating temperature is 100°C-120°C, the reflux condensation temperature is -5°C, the reaction time is 10h-12h, and the stirring rate is 35HZ-50HZ.

[0014] Furthermore, in step S2, the dropping speed of trifluoromethanesulfonic acid is 30 mL / s-50 mL / s.

[0015] Further, in step S2, the molar ratio of trifluoromethanesulfonic acid to the crude trifluoromethanesulfonic anhydride is 1.5:1-1.8:1. Further, in step S3, the temperature of gas phase condensation is 7°C, and the settled liquid is collected in a gas-liquid separation tank;

[0016] Furthermore, in step S4, the distillation tower is a multi-layer packed distillation tower; the heavy components are collected at the bottom of the tower and returned to the reactor A to continue to be recycled as reaction raw materials.

[0017] The present invention also provides a system for preparing trifluoromethyl trifluoromethanesulfonate in a semi-continuous manner, which comprises a reactor A, a reactor B, a gas-liquid separator and a distillation tower connected in sequence; a reflux condenser A is arranged between the reactor A and the reactor B, a reflux condenser B is also arranged at the top of the reactor B, and a condenser is arranged between the gas-liquid separator and the reflux condenser B; the liquid separated by the gas-liquid separator is input into the distillation tower through a pump, and enters the distillation tower from the bottom of the distillation tower. Furthermore, a reflux condenser B and a condenser are arranged in sequence between the reactor B and the gas-liquid separator, and a control valve is arranged between the reflux condenser B and the condenser.

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

[0019] The invention utilizes the particularity of acid dehydration condensation and trifluoromethyl group and the characteristics of the reaction between trifluoromethanesulfonic acid and trifluoromethanesulfonic anhydride to disclose a method for producing trifluoromethyl trifluoromethanesulfonate. The method has relatively mild reaction conditions, simple process, high reaction yield and is convenient for realizing large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the system of the present invention.

[0021] In the attached drawings, 1 is a reactor A, 2 is a reactor B, 3 is a gas-liquid separator, 4 is a distillation tower, 5 is a reflux condenser A, 6 is a reflux condenser B, 7 is a condenser, 8 is a control valve, 9 is a collecting tank, and 10 is a shielded pump. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solution of the present invention in conjunction with the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all. Based on the embodiments of the present invention, other embodiments obtained by other persons in the art without creative work are all within the scope of protection of the present invention.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] Example 1

[0025] The present invention provides a method for semi-continuously preparing trifluoromethyl trifluoromethanesulfonate, which comprises the following steps:

[0026] S1. Add 200 kg of phosphorus pentoxide solid powder into reactor A, add trifluoromethanesulfonic acid and phosphorus pentoxide in a molar ratio of 5:1 into reactor A to form a solid-liquid reaction mixture, the reaction temperature is 70°C, the stirring rate is 35HZ, and after reacting for 16 hours, the reactor A is distilled. During the distillation process, the distillation temperature is 85°C, the condenser medium is circulating water, 7°C water condensation is adopted, and the condensation temperature is 7°C.

[0027] The purity of the trifluoromethanesulfonic acid raw material was 99.7%, the fluoride ion content was 8 ppm, and the sulfate ion content was 45 ppm.

[0028] Condensate during S2, distillation is trifluoromethanesulfonic anhydride crude product, which is collected in reactor B, and trifluoromethanesulfonic anhydride crude product is measured by pipeline flowmeter and totals 658kg; Trifluoromethanesulfonic acid is dripped in above-mentioned reactor B, and the dropping rate of trifluoromethanesulfonic acid is 30mL / s, and the mol ratio of trifluoromethanesulfonic acid cumulative dripping amount and described trifluoromethanesulfonic anhydride crude product is 1.5:1, and trifluoromethanesulfonic acid raw material purity is 99.7%, fluoride ion content 8ppm, sulfate ion content 45ppm, then is to stir and carry out reflux reaction at 50HZ at speed; Reflux temperature is 100 DEG C, and reflux condensation adopts chilled water for condensation, and temperature is-5 DEG C, and the chilled water of regulating reflux condenser B6 controls total reflux reaction simultaneously, and total reflux time is 10h.

[0029] S3, adjust the reflux condenser B6, stop the condensation of total reflux, and distill the gas phase. The gas phase material contains trifluoromethyl trifluoromethanesulfonate, sulfur dioxide and a small amount of water. The gas phase of the reactor B2 is passed through the condenser 7 to form a condensate and collected in the gas-liquid separation tank 3. The gas phase of the reactor B2 is subjected to gas phase condensation, and the condenser also uses 7°C circulating water for condensation. The settled liquid is collected in the gas-liquid separation tank, where sulfur dioxide gas escapes and is absorbed in the gas phase, and the gas phase that has not settled is discharged; the liquid phase material further enters the distillation tower 4 for distillation. The method of gas-liquid separation is natural separation of gas and liquid. The liquid separated by the gas-liquid separator 3 is input into the distillation tower 4 through a pump and enters from the lower part of the distillation tower 4.

[0030] S4, the temperature of the distillation tower kettle is controlled to 78 ° C, and the pressure of the distillation tower kettle is controlled to 0.10MPa. The light components at the top of the tower are discharged into the absorption tower for absorption, and the heavy components at the bottom of the tower are mainly anhydride and a small amount of water, which are returned to the reactor A and continue to be recycled as reaction raw materials. In this embodiment, when the temperature of the upper part of the distillation tower is 24 ° C and the liquid level of the tower kettle is about 490mm, the product trifluoromethyl trifluoromethanesulfonate is extracted, and the purity of the obtained product trifluoromethyl trifluoromethanesulfonate is 99.2%, fluoride ion 5pm, sulfate ion 38ppm.

[0031] The yield of trifluoromethyl trifluoromethanesulfonate obtained in this example is 98.5%.

[0032] The distillation tower is a multi-layer packed distillation tower; the heavy components are collected at the bottom of the tower and returned to the reactor A to be continuously recycled as reaction raw materials.

[0033] Example 2

[0034] The present invention provides a method for semi-continuously preparing trifluoromethyl trifluoromethanesulfonate, which comprises the following steps:

[0035] S1. Add 400 kg of phosphorus pentoxide solid powder into reactor A, add trifluoromethanesulfonic acid and phosphorus pentoxide in a molar ratio of 4:1 into reactor A to form a solid-liquid reaction mixture, the reaction temperature is 65°C, the stirring rate is 38HZ, and after stirring the reaction for 16 hours, the reactor A is distilled. During the distillation process, the distillation temperature is 88°C, and the circulating condensed water is condensed with 7°C water.

[0036] The trifluoromethanesulfonic acid raw material has a purity of 99.1%, a fluoride ion content of 10 ppm, and a sulfate ion content of 50 ppm.

[0037] Condensate during S2, distillation is trifluoromethanesulfonic anhydride crude product, which is collected in reactor B, and trifluoromethanesulfonic anhydride crude product is measured by pipeline flowmeter, totaling 1132kg; Trifluoromethanesulfonic acid is dripped in above-mentioned reactor B, and the dropping rate of trifluoromethanesulfonic acid is 50mL / s, and the mol ratio of the cumulative amount of trifluoromethanesulfonic acid added and the trifluoromethanesulfonic anhydride crude product is 1.8:1, then stirs and carries out back flow reaction at a rate of 40HZ; Reflux temperature is 110 DEG C, and reflux condensation adopts chilled water for condensation, and temperature is-5 DEG C, and simultaneously regulates the cooling water control total reflux reaction of reflux condenser B6, and the total reflux time is 12h.

[0038] S3, adjust the reflux condenser B6, stop the condensation of total reflux, and distill the gas phase. The gas phase material contains trifluoromethyl trifluoromethanesulfonate, sulfur dioxide and a small amount of water. The gas phase of the reactor B2 is passed through the condenser 7 to form a condensate and collected in the gas-liquid separation tank 3. The gas phase of the reactor B2 is gas-phase condensed. The condenser also uses 7°C circulating water for condensation, and the temperature of gas phase condensation is 7°C. The settled liquid is collected in the gas-liquid separation tank, where sulfur dioxide gas escapes and is absorbed; the gas phase that has not settled is discharged; the liquid phase material further enters the distillation tower 4 for distillation. The method of gas-liquid separation is natural separation of gas and liquid. The liquid separated by the gas-liquid separator 3 is pumped into the distillation tower 4 and enters from the lower part of the distillation tower 4.

[0039] S4, the tower still temperature of the rectifying tower is controlled to be 60 ℃, by controlling the rectifying tower still pressure to be 0.08MPa, the light component at the top of the tower is discharged into the absorption tower for absorption, and the heavy component at the bottom of the tower is mainly anhydride and a small amount of water, which is re-entered in the reactor A, and continues to be recycled as reaction raw materials, when the temperature in the upper part of the rectifying tower is 25 ℃ and the tower still liquid level is about 520mm, the product trifluoromethyl trifluoromethanesulfonate is extracted at the top of the rectifying tower, and the product trifluoromethyl trifluoromethanesulfonate purity obtained is 99.0%, fluoride ion 8ppm, sulfate ion 42ppm. The yield of the product trifluoromethyl trifluoromethanesulfonate obtained in the present embodiment is 98.3%.

[0040] The distillation tower is a multi-layer packed distillation tower; the heavy components are collected at the bottom of the tower and returned to the reactor A to be continuously recycled as reaction raw materials.

[0041] Example 3

[0042] The present invention provides a method for semi-continuously preparing trifluoromethyl trifluoromethanesulfonate, which comprises the following steps:

[0043] S1. Add 250 kg of phosphorus pentoxide solid powder into reactor A, add trifluoromethanesulfonic acid and phosphorus pentoxide in a molar ratio of 4.5:1 into reactor A to form a solid-liquid reaction mixture, the reaction temperature is 50°C, the stirring rate is 50 Hz, and after stirring the reaction for 16 hours, the reactor A is distilled. During the distillation process, the distillation temperature is 95°C, the circulating condensed water is condensed with 7°C water, and the condensation temperature is 7°C.

[0044] The trifluoromethanesulfonic acid raw material has a purity of 99.3%, a fluoride ion content of 5 ppm, and a sulfate ion content of 26 ppm.

[0045] Condensate during S2 and distillation is a crude trifluoromethanesulfonic anhydride product, which is collected in reactor B, and the crude trifluoromethanesulfonic anhydride product is measured by pipeline flowmeter to total 861kg; Trifluoromethanesulfonic acid is dripped in above-mentioned reactor B, and the dropping rate of trifluoromethanesulfonic acid is 45mL / s, and the mol ratio of the cumulative amount of trifluoromethanesulfonic acid added and the crude trifluoromethanesulfonic anhydride product is 1.6:1, then at a speed of 35HZ, stir and carry out back flow reaction; Reflux temperature is 120 DEG C, and reflux condensation adopts chilled water for condensation, and condensing temperature is-5 DEG C, and the circulating water of regulating reflux condenser B6 controls the total reflux reaction simultaneously, and the total reflux time is 11.5h.

[0046] S3, adjust the reflux condenser B6, stop the condensation of total reflux, and distill the gas phase. The gas phase material contains trifluoromethyl trifluoromethanesulfonate, sulfur dioxide and a small amount of water. The gas phase of the reactor B2 is passed through the condenser 7 to form a condensate and collected in the gas-liquid separation tank 3. The gas phase of the reactor B2 is gas-phase condensed. The condenser also uses 7°C circulating water for condensation, and the temperature of gas phase condensation is 7°C. The settled liquid is collected in the gas-liquid separation tank, where sulfur dioxide gas escapes and is absorbed; the gas phase that has not settled is discharged; the liquid phase material further enters the distillation tower 4 for distillation. The method of gas-liquid separation is natural separation of gas and liquid. The liquid separated by the gas-liquid separator 3 is pumped into the distillation tower 4 and enters from the lower part of the distillation tower 4.

[0047] S4, the tower still temperature of the rectifying tower is controlled to be 50 ℃, by controlling the rectifying tower still pressure to be 0.09MPa, the light component at the top of the tower is discharged into the absorption tower for absorption, and the heavy component at the bottom of the tower is mainly anhydride and a small amount of water, which is re-entered in the reactor A, and continues to be recycled as reaction raw materials, when the temperature in the upper part of the rectifying tower is 23 ℃ and the tower still liquid level is about 490mm, the product trifluoromethyl trifluoromethanesulfonate is extracted at the top of the rectifying tower, and the product trifluoromethyl trifluoromethanesulfonate purity obtained is 99.3%, fluoride ion 4ppm, and sulfate ion 19ppm. The yield of the product trifluoromethyl trifluoromethanesulfonate obtained in the present embodiment is 98.9%.

[0048] The distillation tower is a multi-layer packed distillation tower; the heavy components are collected at the bottom of the tower and returned to the reactor A to be continuously recycled as reaction raw materials.

[0049] Example 4

[0050] The present invention provides a method for semi-continuously preparing trifluoromethyl trifluoromethanesulfonate, which comprises the following steps:

[0051] S1. Add 320 kg of phosphorus pentoxide solid powder into reactor A, add trifluoromethanesulfonic acid and phosphorus pentoxide in a molar ratio of 4.2:1 into reactor A to form a solid-liquid reaction mixture, the reaction temperature is 55°C, the stirring rate is 50 Hz, and after stirring the reaction for 16 hours, the reactor A is distilled. During the distillation process, the distillation temperature is 95°C, and the circulating condensed water is condensed with 7°C water.

[0052] The trifluoromethanesulfonic acid raw material has a purity of 99.6%, a fluoride ion content of 6 ppm, and a sulfate ion content of 35 ppm.

[0053] Condensate during S2 and distillation is a crude trifluoromethanesulfonic anhydride product, which is collected in reactor B, and the crude trifluoromethanesulfonic anhydride product is measured by pipeline flowmeter to total 742kg; Trifluoromethanesulfonic acid is dripped in above-mentioned reactor B, and the dropping rate of trifluoromethanesulfonic acid is 40mL / s, and the mol ratio of the cumulative amount of trifluoromethanesulfonic acid added and the crude trifluoromethanesulfonic anhydride product is 1.7:1, then at a rate of 50HZ, stir and carry out back flow reaction; Reflux temperature is 115 DEG C, and reflux condensation adopts chilled water for condensation, and temperature is-5 DEG C, and the circulating water of reflux condenser B6 is regulated simultaneously to control the total reflux reaction, and the total reflux time is 10.5h.

[0054] S3, adjust the reflux condenser B6, stop the condensation of total reflux, and distill the gas phase. The gas phase material contains trifluoromethyl trifluoromethanesulfonate, sulfur dioxide and a small amount of water. The gas phase of the reactor B2 is passed through the condenser 7 to form a condensate and collected in the gas-liquid separation tank 3. The gas phase of the reactor B2 is subjected to gas phase condensation, and the condenser also uses 7°C circulating water for condensation. The settled liquid is collected in the gas-liquid separation tank, where sulfur dioxide gas escapes and is absorbed in the gas phase, and the gas phase that has not settled is discharged and discharged to the alkali liquid treatment tower; the liquid phase material further enters the distillation tower 4 for distillation. The method of gas-liquid separation is natural separation of gas and liquid. The liquid separated by the gas-liquid separator 3 is input into the distillation tower 4 through a pump and enters from the lower part of the distillation tower 4.

[0055] S4, the temperature of the distillation tower kettle is controlled to 70°C, and the pressure of the distillation tower kettle is controlled to 0.087MPa. The light components at the top of the tower are discharged into the absorption tower for absorption, and the heavy components at the bottom of the tower are mainly anhydride and a small amount of water, which are returned to the reactor A and continue to be recycled as reaction raw materials. When the temperature in the upper part of the distillation tower is 20°C and the liquid level in the tower kettle is about 400mm, the product trifluoromethyl trifluoromethanesulfonate is extracted from the upper part of the distillation tower. The purity of the obtained product trifluoromethyl trifluoromethanesulfonate is 99.5%, the fluoride ion is 6ppm, and the sulfate ion is 28ppm. The yield of the product trifluoromethyl trifluoromethanesulfonate obtained in this embodiment is 99.0%.

[0056] The distillation tower is a multi-layer packed distillation tower; the heavy components are collected at the bottom of the tower and returned to the reactor A to be continuously recycled as reaction raw materials.

[0057] like Figure 1 As shown, the present invention also provides a system for semi-continuous preparation of trifluoromethyl trifluoromethanesulfonate, which includes a reactor A1, a reactor B2, a gas-liquid separator 3 and a distillation tower 4 connected in sequence; a reflux condenser A5 is arranged between the reactor A1 and the reactor B2, a reflux condenser B6 is also arranged at the top of the reactor B2, and a condenser 7 is arranged between the gas-liquid separator 3 and the reflux condenser B6; the liquid separated by the gas-liquid separator 3 is input into the distillation tower 4 from the bottom through a pump and enters the distillation tower 4 from the lower part.

[0058] The pump is a canned motor pump 10 .

[0059] A reflux condenser B6 and a condenser 7 are sequentially arranged between the reactor B2 and the gas-liquid separator 3 , and a control valve 8 is arranged between the reflux condenser B6 and the condenser 7 .

[0060] When the system of the present invention is in use, the reactor A1 is provided with a filling port for feeding raw materials, and the reactor A1 is provided with a stirring device for stirring the raw materials to promote mixing. By pumping the raw materials, phosphorus pentoxide solid powder and trifluoromethanesulfonic acid are sequentially added into the reactor A1 to form a solid-liquid reaction mixture, and after stirring and reacting for 16 hours, distillation is performed. During the distillation process, the reactor A1 is heated, and the reflux condenser A5 is reflux-condensed. The reflux condenser A5 is arranged at the top of the reactor A1. The crude trifluoromethanesulfonic anhydride obtained by the reaction is added to the reactor B2 through the reflux condenser A5, and the bottom of the reactor B2 is connected with a sewage tank.

[0061] In the reaction kettle B2, trifluoromethanesulfonic acid was added dropwise to the reaction kettle B, stirred, and the circulating water of the reflux condenser B6 was adjusted to control the total reflux reaction. The reaction time was 10h to 12h.

[0062] After the reflux reaction is completed, the reflux condenser B6 is adjusted to stop the condensation of the total reflux, and the gas phase is discharged. The gas phase material contains trifluoromethyl trifluoromethanesulfonate, sulfur dioxide and a small amount of water. The condenser 7 is opened, and the gas phase material enters the gas-liquid separator 3 through the condenser 7, wherein the sulfur dioxide gas escapes from the top of the gas-liquid separator 3 in the form of gas phase and is absorbed; the liquid phase material is deposited from the bottom of the gas-liquid separator 3 and enters the distillation tower 4 for distillation through the shielded pump 10.

[0063] By controlling the heat of the bottom of the distillation tower 4 and the cooling capacity of the top of the tower, that is, by controlling the temperature of the bottom of the tower and the temperature of the top of the tower, trifluoromethyl trifluoromethanesulfonate is extracted from the distillation tower 4 and enters the collecting tank 9; the light components at the top of the tower are discharged into the absorption tower for absorption, and the heavy components at the bottom of the tower are mainly anhydride and a small amount of water, which are returned to the reactor A through a pipeline and continue to be recycled as a reaction raw material. The distillation tower is a multi-layer filler distillation tower, which is conducive to full contact and effective separation of materials, and can realize single tower separation of the upper, middle and lower parts of the distillation tower, wherein trifluoromethyl trifluoromethanesulfonate is taken out from the upper part of the tower, wherein the purity of the product trifluoromethyl trifluoromethanesulfonate is ≥99.0%, fluoride ion ≤9ppm, and sulfate ≤45ppm. The yield of the product trifluoromethyl trifluoromethanesulfonate obtained in this embodiment is greater than 98.0%.

[0064] The reaction equation to which the present invention relates is as follows:

[0065] 6CF3SO3H+P2O3→3(CF3SO2)2O+2H3PO4

[0066] 2CF3SO3H+(CF3SO2)2O→2CF3SO2OCF3+2SO2↑+H2O.

[0067] At present, the technical solution of the present invention has been put into pilot production, that is, a small-scale experiment before the large-scale mass production of the product. After the pilot production was completed, a user survey was conducted on a small scale, and the survey results showed that user satisfaction was high. Now, preparations have been started for the formal production and industrialization of the product (including intellectual property risk warning survey).

[0068] The above-described embodiments are preferred embodiments of the present invention, but not exhaustive of the feasible implementations of the present invention. For those skilled in the art, various improvements made without departing from the spirit and essence of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A semi-continuous method for preparing trifluoromethyl trifluoromethanesulfonate, characterized in that: It includes the following steps, S1. In reactor A, add phosphorus pentoxide and trifluoromethanesulfonic acid in sequence to form a solid-liquid reaction mixture, stir and react at 50°C-70°C for 16 hours, and then distill reactor A; The condensate during S2 and distillation is a crude trifluoromethanesulfonic anhydride product, which is collected in a reactor B; trifluoromethanesulfonic acid is added dropwise to the above-mentioned reactor B, and then refluxed under stirring; S3, stop the reflux condensation, condense the gas phase of reactor B to form condensate and collect it in a gas-liquid separation tank, and pump the collected liquid into a distillation tower for distillation; S4, the distillation tower kettle pressure is 0.08MPa-0.1MPa, and the kettle temperature is 50℃-78℃; In step S1, the molar ratio of trifluoromethanesulfonic acid to phosphorus pentoxide is 4:1-5:1; the purity of the trifluoromethanesulfonic acid is ≥99.0%, the content of fluoride ions in the trifluoromethanesulfonic acid is ≤10ppm, and the content of sulfate ions is ≤50ppm; the stirring frequency is 35Hz-50Hz; In step S1, the distillation temperature is 85°C-95°C, and the condensation temperature is 7°C; In step S2, the reflux heating temperature is 100°C-120°C, the reflux condensation temperature is -5°C, the reaction time is 10h-12h, and the stirring frequency is 35Hz-50Hz; In step S2, the dropping speed of trifluoromethanesulfonic acid is 30 mL / s-50 mL / s; In step S2, the molar ratio of trifluoromethanesulfonic acid to the crude trifluoromethanesulfonic anhydride is 1.5:1-1.8:1; In step S3, the temperature of gas phase condensation is 7°C, and the settled liquid is collected in a gas-liquid separation tank; In step S4, the distillation tower is a multi-layer packed distillation tower; the heavy components are collected at the bottom of the tower and returned to the reactor A to be continuously recycled as reaction raw materials.

2. A system for semi-continuous preparation of trifluoromethyl trifluoromethanesulfonate, used for the method for semi-continuous preparation of trifluoromethyl trifluoromethanesulfonate according to claim 1, characterized in that: The invention comprises a reaction kettle A (1), a reaction kettle B (2), a gas-liquid separator (3) and a distillation tower (4) which are connected in sequence; a reflux condenser A (5) is arranged between the reaction kettle A (1) and the reaction kettle B (2); a reflux condenser B (6) is also arranged at the top of the reaction kettle B (2); a condenser (7) is arranged between the gas-liquid separator (3) and the reflux condenser B (6); and the liquid separated by the gas-liquid separator (3) is input into the distillation tower (4) through a pump and enters from the lower part of the distillation tower (4).

3. A semi-continuous preparation system of trifluoromethyl trifluoromethanesulfonate according to claim 2, characterized in that: A reflux condenser B (6) and a condenser (7) are arranged in sequence between the reaction kettle B (2) and the gas-liquid separator (3), and a control valve (8) is arranged between the reflux condenser B (6) and the condenser (7).

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