A method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogs

Abstract

The invention discloses a method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogs, comprising the following steps: (1) adsorption: the crude product of trifluoromethanesulfonic anhydride or its analogs is passed through a fixed bed equipped with an adsorbent to obtain a purified product; (2) detection: detecting whether the content of trifluoromethanesulfonic anhydride or its analogs in the purified product meets the standard, if so, the purification is completed; if not, proceeding to the next step; (3) regeneration: using an alkaline desorbent on the fixed bed to remove trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent; and repeating steps (1) and (2). The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogs of the invention simplifies the operation process, reduces the cost and improves the yield.

Description

Technical Field

[0001] The invention relates to a method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogs. Background Art

[0002] Trifluoromethanesulfonic anhydride is a derivative of trifluoromethanesulfonic acid. It is a commonly used intermediate and catalyst in the fields of fine chemicals and pharmaceutical chemicals. As an intermediate, it can be used to synthesize nucleosides, antibiotics, steroids, proteins, vitamins, etc.; as a catalyst, it can be used for polymerization, esterification, alkylation and other reactions. In addition, trifluoromethanesulfonic anhydride can also be used in the fields of plastics industry, electronic chemical industry, sugar industry, etc.

[0003] The industrial preparation method of trifluoromethanesulfonic anhydride mainly adopts the reaction of trifluoromethanesulfonic acid and phosphorus pentoxide, and the reaction equation is as follows:

[0004] (1)6CF3SO3H+P2O5→6(CF3SO2)2O+2H3PO4

[0005] The main impurity trifluoromethanesulfonic acid accounts for about 5% of the product obtained by this reaction, and it also contains a small amount of trifluoromethyl trifluoromethanesulfonate, fluoride ions, sulfate ions, etc.

[0006] The boiling points of impurities such as trifluoromethanesulfonic acid (boiling point: 162°C) and trifluoromethyl trifluoromethanesulfonate (boiling point: 21°C) are significantly different from the boiling point of trifluoromethanesulfonic anhydride (boiling point: 84°C), so the traditional purification process is repeated distillation or rectification. Although these methods can also make the purity of trifluoromethanesulfonic anhydride meet the requirements, the multiple distillation or rectification process inevitably causes product loss, which reduces the yield.

[0007] In addition, reactive distillation can also purify trifluoromethanesulfonic anhydride. Japanese patent JP2002088050 reports adding a certain amount of phosphorus pentoxide to the crude product of trifluoromethanesulfonic anhydride, and removing trifluoromethanesulfonic acid and sulfate ions in trifluoromethanesulfonic anhydride by reactive distillation. Russian patent RU2282620 reports adding an appropriate amount of phosphorus pentoxide and silicon dioxide to trifluorosulfonic anhydride to remove trifluoromethanesulfonic acid and fluoride ions respectively. Reactive distillation can reduce the content of impurities, but the reaction process requires a certain amount of time, and side reactions also occur during the reaction, such as the generation of SiF4, which may introduce new impurities. After the reaction is completed, the problem of distillation is also involved, and the reagents that need to be added increase the purification cost.

[0008] In summary, the main difficulty in purifying trifluoromethanesulfonic anhydride is to remove the impurity trifluoromethanesulfonic acid and avoid product loss caused by repeated distillation or rectification.

[0009] In addition, analogs of trifluoromethanesulfonic anhydride such as trimethylsilyl trifluoromethanesulfonate, trifluoromethanesulfonyl chloride, and methyl trifluoromethanesulfonate often contain impurities such as trifluoromethanesulfonic acid. This problem is widespread and needs to be solved urgently. A simpler and more efficient purification process needs to be developed. Summary of the invention

[0010] The technical problem to be solved by the present invention is to overcome the problems of complicated purification process, high cost and low yield of the existing trifluoromethanesulfonic anhydride or its analogs, and to provide a purification method for the crude product of trifluoromethanesulfonic anhydride or its analogs.

[0011] The present invention solves the above technical problems through the following technical solutions:

[0012] A method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogs, the purification method comprising the following steps:

[0013] (1) Adsorption: The crude product of trifluoromethanesulfonic anhydride or its analogue is passed through a fixed bed containing an adsorbent to obtain a purified product; the adsorbent is a basic anion exchange resin that does not contain an active H group;

[0014] The crude product of trifluoromethanesulfonic anhydride includes trifluoromethanesulfonic anhydride, trifluoromethanesulfonic acid and other impurities;

[0015] and / or, the crude product of the analog of trifluoromethanesulfonic anhydride includes any one of trimethylsilyl trifluoromethanesulfonate, trifluoromethanesulfonyl chloride and methyl trifluoromethanesulfonate, as well as trifluoromethanesulfonic acid and other impurities;

[0016] (2) Detection: Detecting whether the content of the trifluoromethanesulfonic anhydride or its analogue in the purified product meets the standard. If so, purification is completed; if not, proceeding to the next step; the standard is that the content of the trifluoromethanesulfonic anhydride or its analogue is not less than 98%;

[0017] (3) Regeneration: removing the trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent using an alkaline desorbent on the fixed bed; and repeating steps (1) and (2).

[0018] In the present invention, the fixed bed is conventional in the art, such as an exchange column or an adsorption tower.

[0019] In the present invention, the crude product of trifluoromethanesulfonic anhydride or its analogues enters the fixed bed by conventional methods in the art, preferably by being pumped into the fixed bed by a delivery pump.

[0020] In the present invention, the alkaline desorbent enters the fixed bed by conventional methods in the art, preferably by being pumped into the fixed bed by a delivery pump.

[0021] In the present invention, the alkaline anion exchange resin containing no active H groups is conventional in the art, preferably a basic anion exchange resin containing no NH and / or NH2 groups, such as a basic anion exchange resin containing quaternary ammonium salts and / or tertiary amines.

[0022] In the present invention, the alkaline anion exchange resin containing no active H group is conventional in the art and may be a macroporous or gel-type weakly basic anion exchange resin and / or a macroporous or gel-type strongly basic anion exchange resin; for example, the macroporous or gel-type weakly basic anion exchange resin includes one or more of D301, 301, D354, D370, Amberlite IRA-93, DIAION WA-30 and pyridines; the macroporous or gel-type strongly basic anion exchange resin includes one or more of D201, 201, Amberlite IRA-400, Dowex-1, D251, IRA-900 and DIAION SA-10A.

[0023] The pyridine macroporous or gel-type weakly basic anion exchange resin can be prepared according to conventional methods in the art, for example, by referring to the literature for synthesis, Wang Shouting, Chen Weizhu, He Binglin. Synthesis of α-aminopyridine resin and study on its adsorption and elution properties for Au(III), Journal of Advanced Chemistry, 81-86, 8(1), 1987.

[0024] In step (2), preferably, the standard is that the content of trifluoromethanesulfonic anhydride or its analogue is not less than 99%; more preferably, the standard is that the content of trifluoromethanesulfonic anhydride or its analogue is not less than 99.5%.

[0025] In the present invention, the other impurities are conventional in the art, for example, including fluoride ions and sulfate ions; preferably, in step (2), by 19 The contents of trifluoromethanesulfonic anhydride and trifluoromethanesulfonic acid in the purified product obtained in step (1) are detected by F nuclear magnetic resonance and gas chromatography; and / or the contents of fluoride ions and sulfate ions in the purified product obtained in step (1) are detected by ion chromatography.

[0026] In the present invention, the crude trifluoromethanesulfonic anhydride is a crude product obtained from a conventional reaction process of trifluoromethanesulfonic acid and phosphorus pentoxide in the art, preferably comprising: 94.8% trifluoromethanesulfonic anhydride, 4.9% trifluoromethanesulfonic acid, 0.03% fluoride ions and 0.01% sulfate ions.

[0027] In the present invention, the crude product of the analog of trifluoromethanesulfonic anhydride is a crude product obtained by a conventional reaction process of trifluoromethanesulfonic acid with trimethylchlorosilane or phosphorus pentachloride in the art, or a crude product obtained by a reaction process of trimethyl orthoformate with trifluoromethanesulfonic anhydride, and preferably comprises: 95.3% to 97.8% of the trifluoromethanesulfonic anhydride analog, 1.5% to 4.2% of trifluoromethanesulfonic acid, 0.005% to 0.007% of fluoride ions, and 0.0078% to 0.012% of sulfate ions.

[0028] In the present invention, the contents of trifluoromethanesulfonic anhydride or its analogs, trifluoromethanesulfonic acid, fluoride ions and sulfate ions are all in percentage by mass.

[0029] In step (3), preferably, the alkaline desorbent further comprises a step of diluting with a diluent before use.

[0030] In the present invention, the alkaline desorbent is a conventional alkaline desorbent in the art, preferably, including one or more strong organic or inorganic alkali solutions; more preferably, it includes one or more of triethylamine, diethylamine, diisopropylamine, pyridine, sodium hydroxide and potassium hydroxide; the volume concentration of the alkaline desorbent is preferably 100%, that is, it does not contain other solvents to prevent the trifluoromethanesulfonic anhydride or its analogs from hydrolyzing.

[0031] In the present invention, the diluent is a conventional diluent in the art, preferably, including alcohol solvents and / or ether solvents; more preferably, the alcohol solvent includes one or more of methanol, ethanol, isopropanol and tert-butyl alcohol; the ether solvent includes one or more of tetrahydrofuran, ethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,4-dioxane, 2-methyltetrahydrofuran and isopropyl ether; the volume concentration of the diluent is preferably 100%, that is, it does not contain other solvents to prevent the trifluoromethanesulfonic anhydride or its analogs from hydrolyzing.

[0032] Preferably, the mass fraction of the alkaline desorbent dissolved in the diluent is 0.2%-20%.

[0033] In the present invention, the mass fraction of the alkaline desorbent dissolved in the diluent refers to the ratio of the mass of the alkaline desorbent to the mass of the alkaline desorbent solution after dilution with the diluent.

[0034] Preferably, in step (1), the air velocity of the delivery pump is 0.1-5h -1 In step (3), the air velocity of the delivery pump is 0.1-10h -1 .

[0035] In step (1) of the present invention, the working temperature of the adsorption is conventional in the art, preferably -10°C to 50°C, more preferably -5°C to 35°C, for example -5°C, 0°C, 25°C, 30°C or 35°C.

[0036] Furthermore, the purification method also includes recovering the trifluoromethanesulfonic acid and other impurities obtained in step (3) for preparing trifluoromethanesulfonate.

[0037] Furthermore, the purification method also includes pretreatment of the crude product of trifluoromethanesulfonic anhydride or its analogs; the pretreatment is conventional in the art, including distillation or rectification to remove low-boiling impurities.

[0038] Furthermore, the purification method further comprises: when the purified product meets the standard, performing the regeneration step of step (3), collecting the obtained adsorbent, and the collected adsorbent is used for recycling.

[0039] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0040] The reagents and raw materials used in the present invention are commercially available.

[0041] The positive and progressive effects of the present invention are:

[0042] 1. The operation flow of the method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues is simplified.

[0043] 2. By using a reusable adsorbent, the cost required for the purification process of a crude product of trifluoromethanesulfonic anhydride or its analogues is reduced.

[0044] 3. The yield of the purification method of the crude product of trifluoromethanesulfonic anhydride or its analogues is improved. DETAILED DESCRIPTION

[0045] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0046] In the following examples, room temperature refers to 25°C.

[0047] Example 1

[0048] Raw materials: The crude product of trifluoromethanesulfonic anhydride is obtained by the reaction of trifluoromethanesulfonic acid and phosphorus pentoxide. Its main components are shown in Table 1:

[0049] Table 1 Crude product composition of trifluoromethanesulfonic anhydride

[0050]

[0051]

[0052] Adsorbent: D301 (macroporous weakly basic anion exchange resin);

[0053] Alkaline desorbent: 1% sodium hydroxide in methanol solution;

[0054] Purification process: (1) Adsorption: at 0°C, use a space velocity of 1.0 h -1 The crude product of trifluoromethanesulfonic anhydride (4000 mL) was passed through an ion exchange column containing 100 mL of adsorbent D301 by a delivery pump to obtain a purified product; (2) Detection: by nuclear magnetic resonance ( 19 F NMR, Bruker AM-400) and gas chromatography to detect whether the content of trifluoromethanesulfonic anhydride at the outlet of the ion exchange column meets the standard; if it meets the standard, the purification is completed, and the content of trifluoromethanesulfonic anhydride at the outlet of the ion exchange column meets the standard by nuclear magnetic resonance ( 19 The content of trifluoromethanesulfonic acid at the outlet of the ion exchange column was detected by F NMR (Bruker AM-400) and gas chromatography, and the F - , SO4 2- If the content does not meet the standard, proceed to the next step; (3) Regeneration: use a space velocity of 1.0h -1 The alkaline desorbent is passed through an ion exchange column filled with adsorbent D301 by a delivery pump; trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent are removed; and steps (1) and (2) are repeated. The test results are shown in Table 2. The content of trifluoromethanesulfonic anhydride detected meets the standard, where the standard is that the content of trifluoromethanesulfonic anhydride is greater than or equal to 99.5%; the yield of the purified trifluoromethanesulfonic anhydride product is 81%.

[0055] Table 2 The crude product composition of trifluoromethanesulfonic anhydride after purification

[0056]

[0057] Example 2

[0058] Raw materials: same as in Example 1.

[0059] The space velocity selection of adsorbent, alkaline desorbent and their corresponding delivery pumps is shown in Table 3.

[0060] Purification process: (1) Adsorption: 4000 mL of crude trifluoromethanesulfonic anhydride was introduced into an ion exchange column containing 100 mL of adsorbent using a delivery pump at room temperature to obtain a purified product; (2) Detection: Nuclear magnetic resonance (NMR) 19F NMR, Bruker AM-400) and gas chromatography to detect whether the content of trifluoromethanesulfonic anhydride at the outlet of the ion exchange column meets the standard; if it meets the standard, the purification is completed, and the content of trifluoromethanesulfonic anhydride at the outlet of the ion exchange column meets the standard by nuclear magnetic resonance ( 19 The content of trifluoromethanesulfonic acid at the outlet of the ion exchange column was detected by F NMR (Bruker AM-400) and gas chromatography, and the F - , SO4 2- content; if it does not meet the standard, proceed to the next step; (3) regeneration: use a delivery pump to pass the alkaline desorbent through an ion exchange column filled with adsorbent D301; remove trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent; repeat steps (1) and (2). The test results are shown in Table 3. The content of trifluoromethanesulfonic anhydride detected meets the standard, where the standard is that the content of trifluoromethanesulfonic anhydride is greater than or equal to 99.5%; the yield of the purified trifluoromethanesulfonic anhydride product is shown in Table 3.

[0061] Table 3 Crude product purification information of trifluoromethanesulfonic anhydride

[0062]

[0063] Example 3

[0064] Raw materials: The main components of the crude product of trimethylsilyl trifluoromethanesulfonate are shown in Table 4:

[0065] Table 4 Crude product composition of trimethylsilyl trifluoromethanesulfonate

[0066]

[0067] Adsorbent: 301 (gel weakly basic styrene anion exchange resin);

[0068] Alkaline desorbent: 10% diisopropylamine in 1,4-dioxane solution;

[0069] Purification process: (1) Adsorption: at room temperature, using a space velocity of 0.5 h -1 The crude product of trimethylsilyl trifluoromethanesulfonate (4000 mL) was passed through an ion exchange column containing 100 mL of adsorbent 301 by a delivery pump to obtain a purified product; (2) Detection: by nuclear magnetic resonance ( 19 F NMR, Bruker AM-400) and gas chromatography to detect whether the content of trimethylsilyl trifluoromethanesulfonate at the outlet of the ion exchange column meets the standard; if it does, the purification is completed, and the content of trimethylsilyl trifluoromethanesulfonate at the outlet of the ion exchange column meets the standard by nuclear magnetic resonance ( 19 The content of trifluoromethanesulfonic acid at the outlet of the ion exchange column was detected by F NMR (Bruker AM-400) and gas chromatography, and the F -, SO4 2- If the content does not meet the standard, proceed to the next step; (3) Regeneration: use a space velocity of 1.0h -1 The alkaline desorbent is passed through the ion exchange column by a delivery pump; the trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent are removed; and steps (1) and (2) are repeated. The test results are shown in Table 5. The content of trimethylsilyl trifluoromethanesulfonate detected meets the standard, where the standard is that the content of trimethylsilyl trifluoromethanesulfonate is greater than or equal to 99.5%; the yield of the purified trimethylsilyl trifluoromethanesulfonate product is 80%.

[0070] Table 5: Product composition after crude purification of trimethylsilyl trifluoromethanesulfonate

[0071]

[0072] Example 4

[0073] Raw materials: The main components of crude trifluoromethanesulfonyl chloride are shown in Table 6:

[0074] Table 6 Crude ingredient list of trifluoromethanesulfonyl chloride

[0075]

[0076] Adsorbent: 201 (gel strong basic quaternary amine I anion exchange resin);

[0077] Alkaline desorbent: 1% diethylamine ethanol solution;

[0078] Purification process: (1) Adsorption: at room temperature, the space velocity was 0.2 h -1 The crude trifluoromethanesulfonyl chloride (4000 mL) was passed through an ion exchange column containing 100 mL of adsorbent 201 by a delivery pump to obtain a purified product; (2) Detection: by nuclear magnetic resonance ( 19 FNMR, Bruker AM-400) and gas chromatography to detect whether the trifluoromethanesulfonyl chloride content at the outlet of the ion exchange column meets the standard; if it meets the standard, the purification is completed, and the trifluoromethanesulfonyl chloride content at the outlet of the ion exchange column meets the standard by nuclear magnetic resonance ( 19 The content of trifluoromethanesulfonic acid at the outlet of the ion exchange column was detected by F NMR (Bruker AM-400) and gas chromatography, and the F - , SO4 2- If it does not meet the standard, proceed to the next step; (3) Regeneration: use a space velocity of 0.5h -1The alkaline desorbent is passed through the ion exchange column by a delivery pump; the trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent are removed; and steps (1) and (2) are repeated. The test results are shown in Table 7. The content of trifluoromethanesulfonyl chloride detected meets the standard, where the standard is that the content of trifluoromethanesulfonyl chloride is greater than or equal to 99.5%; the yield of the purified trifluoromethanesulfonyl chloride product is 85%.

[0079] Table 7 The crude product composition of trifluoromethanesulfonyl chloride after purification

[0080]

[0081] Example 5

[0082] Raw materials: The main components of crude product of methyl trifluoromethanesulfonate are shown in Table 8:

[0083] Table 8 Crude product composition of methyl trifluoromethanesulfonate

[0084]

[0085] Adsorbent: D370 (macroporous weakly basic styrene anion exchange);

[0086] Alkaline desorbent: 0.2% triethylamine in tetrahydrofuran solution;

[0087] Purification process: (1) Adsorption: at room temperature, using a space velocity of 3.0 h -1 The crude product of methyl trifluoromethanesulfonate (4000 mL) was passed through an ion exchange column containing 100 mL of adsorbent D370 by a delivery pump to obtain a purified product; (2) Detection: by nuclear magnetic resonance ( 19 F NMR, Bruker AM-400) and gas chromatography to detect whether the content of methyl trifluoromethanesulfonate at the outlet of the ion exchange column meets the standard; if it meets the standard, the purification is completed, and the content of methyl trifluoromethanesulfonate at the outlet of the ion exchange column meets the standard by using nuclear magnetic resonance ( 19 The content of trifluoromethanesulfonic acid at the outlet of the ion exchange column was detected by F NMR (Bruker AM-400) and gas chromatography, and F was detected by using an ion chromatograph (Thermo IC-1100). - , SO4 2- If it does not meet the standard, proceed to the next step; (3) Regeneration: use a space velocity of 4.0h -1 The alkaline desorbent is passed through the ion exchange column by a delivery pump; the trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent are removed; and steps (1) and (2) are repeated. The test results are shown in Table 9. The content of methyl trifluoromethanesulfonate detected meets the standard, where the standard is that the content of methyl trifluoromethanesulfonate is greater than or equal to 99.5%; the yield of the purified product of methyl trifluoromethanesulfonate is 83%.

[0088] Table 9 Product composition of purified methyl trifluoromethanesulfonate

[0089]

[0090] Example 6 and Comparative Example 1

[0091] The raw materials and purification methods in Examples 6-1 to 6-7 and Comparative Example 1 were the same as those in Example 1, and the crude trifluoromethanesulfonic anhydride was purified at different working temperatures.

[0092] The corresponding working temperature selection is shown in Table 10.

[0093] Table 10: Crude product purification information of trifluoromethanesulfonic anhydride

[0094]

[0095] Comparative Example 2

[0096] Raw materials: same as Example 1

[0097] Alkaline adsorbent: D302 (primary amine type anion exchange resin);

[0098] Desorbent: 1% sodium hydroxide in methanol solution;

[0099] Purification process: (1) Adsorption: at 0°C, use a space velocity of 2.0 h -1 The crude product of trifluoromethanesulfonic anhydride (4000 mL) was passed through an ion exchange column containing 100 mL of adsorbent D302 by a delivery pump to obtain a purified product; (2) Detection: by nuclear magnetic resonance ( 19 F NMR, Bruker AM-400) and gas chromatography to detect whether the content of trifluoromethanesulfonic anhydride at the outlet of the ion exchange column meets the standard; if it meets the standard, the purification is completed, and the content of trifluoromethanesulfonic anhydride at the outlet of the ion exchange column meets the standard by nuclear magnetic resonance ( 19 The content of trifluoromethanesulfonic acid at the outlet of the ion exchange column was detected by F NMR (Bruker AM-400) and gas chromatography, and the F - , SO4 2- If it does not meet the standard, proceed to the next step; (3) Regeneration: use a space velocity of 3.0h -1 The alkaline desorbent is passed through an ion exchange column containing adsorbent D302 by a delivery pump; trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent are removed; and steps (1) and (2) are repeated. The test results are shown in Table 11. The content of trifluoromethanesulfonic anhydride detected meets the standard, where the standard is that the content of trifluoromethanesulfonic anhydride is greater than or equal to 99.5%; the yield of the purified trifluoromethanesulfonic anhydride product is 60%.

[0100] Table 11: Product composition after crude purification of trifluoromethanesulfonic anhydride

[0101]

[0102] Although the use of alkaline anion exchange resin containing active H groups as an adsorbent can ultimately achieve the standard of purified product, the poor adsorption effect of the adsorbent leads to repeated steps (1) to (3), which increases product loss, reduces yield, and increases resin consumption.

Claims

1. A method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogs, characterized in that: The purification method comprises the following steps: (1) Adsorption: The crude product of trifluoromethanesulfonic anhydride or its analogue is passed through a fixed bed containing an adsorbent to obtain a purified product; the adsorbent is a basic anion exchange resin that does not contain an active H group; The crude product of trifluoromethanesulfonic anhydride includes trifluoromethanesulfonic anhydride, trifluoromethanesulfonic acid and other impurities; and / or, the crude product of the analog of trifluoromethanesulfonic anhydride includes any one of trimethylsilyl trifluoromethanesulfonate, trifluoromethanesulfonyl chloride and methyl trifluoromethanesulfonate, as well as trifluoromethanesulfonic acid and other impurities; The other impurities are fluoride ions and sulfate ions; (2) Detection: Detecting whether the content of the trifluoromethanesulfonic anhydride or its analogue in the purified product meets the standard. If so, purification is completed; if not, proceeding to the next step; the standard is that the content of the trifluoromethanesulfonic anhydride or its analogue is not less than 98%; (3) Regeneration: removing the trifluoromethanesulfonic acid and other impurities adsorbed on the adsorbent using an alkaline desorbent on the fixed bed; and repeating steps (1) and (2); In step (1), the basic anion exchange resin containing no active H groups is selected from one or more of a macroporous or gel-type weakly basic anion exchange resin and a macroporous or gel-type strongly basic anion exchange resin; In step (1), the adsorption working temperature is -10°C to 50°C; In step (3), the alkaline desorbent includes one or more of triethylamine, diethylamine, diisopropylamine, pyridine, sodium hydroxide and potassium hydroxide.

2. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 1, characterized in that: The fixed bed is a fixed bed exchange column or a fixed bed adsorption tower; And / or, the crude product of trifluoromethanesulfonic anhydride or its analogues and / or the alkaline desorbent are pumped into the fixed bed via a delivery pump.

3. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues as claimed in claim 2, characterized in that: The working temperature of the adsorption is -5°C to 35°C.

4. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues as claimed in claim 3, characterized in that: The working temperature of the adsorption is -5°C, 0°C, 25°C, 30°C or 35°C.

5. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 1, characterized in that: The alkaline anion exchange resin containing no active H groups is an alkaline anion exchange resin containing no NH and / or NH2 groups.

6. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 5, characterized in that: The alkaline anion exchange resin containing no active H groups is an alkaline anion exchange resin containing quaternary ammonium salts and / or tertiary amines; And / or, the macroporous or gel-type weakly basic anion exchange resin is selected from one or more of D301, 301, D354, D370, AmberliteIRA-93, DIAION WA-30 and pyridines; the macroporous or gel-type strongly basic anion exchange resin is selected from one or more of D201, 201, Amberlite IRA-400, Dowex-1, D251, IRA-900 and DIAION SA-10A.

7. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 1, characterized in that: In step (1), the standard is that the content of trifluoromethanesulfonic anhydride or its analogue is not less than 99%.

8. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 7, characterized in that: In step (1), the standard is that the content of trifluoromethanesulfonic anhydride or its analogue is not less than 99.5%.

9. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 1, characterized in that: The crude product of trifluoromethanesulfonic anhydride is a crude product obtained from the reaction process of trifluoromethanesulfonic acid and phosphorus pentoxide; And / or, the crude product of the analog of trifluoromethanesulfonic anhydride is a crude product obtained by a reaction process of trifluoromethanesulfonic acid with trimethylchlorosilane or phosphorus pentachloride or a crude product obtained by a reaction process of trimethyl orthoformate with trifluoromethanesulfonic anhydride.

10. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 9, characterized in that: In step (2), by 19 F nuclear magnetic resonance and gas chromatography are used to detect the contents of trifluoromethanesulfonic anhydride and trifluoromethanesulfonic acid in the purified product obtained in step (1); and / or, ion chromatography is used to detect the contents of fluoride ions and sulfate ions in the purified product obtained in step (1); And / or, the crude product of trifluoromethanesulfonic anhydride comprises: 94.8% of trifluoromethanesulfonic anhydride, 4.9% of trifluoromethanesulfonic acid, 0.03% of fluoride ions and 0.01% of sulfate ions; And / or, the crude product of the trifluoromethanesulfonic anhydride analogue comprises: 95.3% to 97.8% of the trifluoromethanesulfonic anhydride analogue, 1.5% to 4.2% of trifluoromethanesulfonic acid, 0.005% to 0.007% of fluoride ions and 0.0078% to 0.012% of sulfate ions.

11. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 1, characterized in that: In step (3), the alkaline desorbent further comprises a step of diluting with a diluent before use.

12. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 11, characterized in that: In step (3), the volume concentration of the alkaline desorbent is 100%; And / or, in step (3), the diluent is an alcohol solvent and / or an ether solvent; And / or, in step (3), the mass fraction of the alkaline desorbent dissolved in the diluent is 0.2%-20%, and the mass fraction of the alkaline desorbent dissolved in the diluent refers to the ratio of the mass of the alkaline desorbent to the mass of the alkaline desorbent solution after dilution with the diluent.

13. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 12, characterized in that: The alcohol solvent is selected from one or more of methanol, ethanol, isopropanol and tert-butanol; the ether solvent is selected from one or more of tetrahydrofuran, ethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,4-dioxane, 2-methyltetrahydrofuran and isopropyl ether; And / or, the volume concentration of the diluent is 100%.

14. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 2, characterized in that: In step (1), the air velocity of the delivery pump is 0.1-5h -1 In step (3), the air velocity of the delivery pump is 0.1-10h -1 .

15. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 1, characterized in that: The purification method further comprises recovering the trifluoromethanesulfonic acid and other impurities obtained in step (3) to prepare trifluoromethanesulfonate; And / or, the purification method further comprises pretreatment of the crude product of trifluoromethanesulfonic anhydride or its analogs, wherein the pretreatment is distillation or rectification.

16. The method for purifying a crude product of trifluoromethanesulfonic anhydride or its analogues according to claim 1, characterized in that: The purification method further comprises, if the purified product meets the standard, performing a regeneration step of step (3), and collecting the obtained adsorbent.

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