Molecularly imprinted polymer for adsorbing perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomers and preparation method and application thereof

Abstract

The invention discloses a molecular imprinting polymer for adsorbing perfluoro (4-methyl-3,6-dioxa-7-octenes) sulfonyl fluoride isomers and its preparation method and application, belonging to the field of molecular imprinting materials and organic separation technology, and the preparation method includes: the template molecule perfluoro (4-methyl-3,6-dioxa-7-octenes) sulfonyl fluoride isomers and functional monomers are mixed in an organic solvent for prepolymerization to obtain a template-monomer mixed solution; a cross-linking agent and an initiator are added to the template-monomer mixed solution, and the temperature is increased under an inert gas atmosphere for polymerization, and after the reaction is completed, the obtained product solution is sequentially subjected to solid-liquid separation, grinding and elution to obtain the molecular imprinting polymer. The molecular imprinting polymer has good adsorption and excellent specificity, and the molecular imprinting polymer is used to purify and separate the crude product of perfluoro (4-methyl-3,6-dioxa-7-octenes) sulfonyl fluoride, so as to improve the accuracy of isomer separation.

Description

Technical Field

[0001] The invention relates to the technical field of molecular imprinting materials and organic separation, and in particular to a molecular imprinting polymer for adsorbing perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomers, and a preparation method and application thereof. Background Art

[0002] Perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride (PSVE) has excellent heat resistance, mechanical properties, electrochemical properties and chemical stability. It is an important comonomer of organic fluorine materials. It can introduce functional sulfonic acid group chains into polymers. After copolymerization with other monomers, it can prepare fluororesins, fluororubbers and other materials with special functions that can be used under specific conditions. It has broad application prospects in the field of fluorine chemical industry. When using perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride for polymer polymerization (such as when used to prepare perfluorosulfonic acid ion exchange resin), its quality requirements are extremely high (purity ≥ 99.9%). Therefore, it is necessary to study the separation and purification method of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride.

[0003] In the prior art, the synthesis methods of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride mainly include sulfonyl fluoridation and thermal decarboxylation. The crude products synthesized by the corresponding methods usually contain a variety of impurities, including isomers of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride. At present, the separation and purification of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride usually adopts the distillation method (such as the Chinese patent document with publication number CN105753742A), but the distillation process easily causes it to decompose, affecting the yield. A Chinese patent document with publication number CN117510382A discloses a method for separating and purifying perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride. When a crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product is separated and purified by silica gel column chromatography, a magnetic field is applied to significantly increase the polarity difference between the perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride and other impurities in the crude product, thereby making it easier to separate and purify the perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride. However, the method cannot selectively remove isomers in the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product.

[0004] Molecular imprinting technology can be used to synthesize polymers that have specific recognition and selective adsorption functions for specific target molecules (template molecules) and their structural analogs. The advantages of molecular imprinting polymers are their high selectivity, high stability and ease of preparation. They have been widely studied in the fields of biomedicine, environmental monitoring, food safety, etc. However, in the prior art, there are no reports on molecular imprinting polymers that selectively adsorb perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomers. Summary of the invention

[0005] The invention provides a molecular imprinting polymer for adsorbing perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomers and a preparation method thereof, so as to solve the problems of high energy consumption, easy decomposition of process products, increased three wastes and substandard product purity in the current perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride crude product rectification and purification method.

[0006] The specific technical solutions adopted are as follows:

[0007] A method for preparing a molecularly imprinted polymer for adsorbing perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomers comprises the following steps:

[0008] (1) mixing the template molecule perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomer and the functional monomer in an organic solvent for prepolymerization to obtain a template-monomer mixed solution;

[0009] (2) adding a crosslinking agent and an initiator to the template-monomer mixture, heating the mixture under an inert gas atmosphere for polymerization, and after the reaction is completed, sequentially performing solid-liquid separation, grinding and elution on the obtained product solution to obtain the molecularly imprinted polymer;

[0010] The structural formula of the template molecule perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomer is FSO2CF2CF2O CF2 CF(CF3)OCF=CF2;

[0011] Functional monomers include methacrylic acid, methyl methacrylate, acrylamide or 2-vinylpyridine.

[0012] The method of the invention uses a specific process flow and relies on the effects of functional monomers, crosslinking agents and initiators to stably imprint the template molecule perfluoro (4-methyl-3, 6-dioxa-7-octene) sulfonyl fluoride isomer onto the polymer, and the obtained product molecular imprinted polymer has good adsorption performance and excellent specificity; the molecular imprinted polymer with specific recognition and selective adsorption characteristics is used to purify and separate the crude perfluoro (4-methyl-3, 6-dioxa-7-octene) sulfonyl fluoride, which can improve the accuracy of isomer separation.

[0013] Preferably, the functional monomer is methyl methacrylate and / or acrylamide, more preferably methyl methacrylate; the molar ratio of the template molecule perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomer to the functional monomer is 1:3-5; under the above preferred conditions, it is helpful to better carry out the prepolymerization reaction and the raw material utilization rate is high.

[0014] Specifically, the organic solvent includes at least one of methanol, ethanol, acetonitrile and dichloromethane, preferably methanol and / or acetonitrile, and more preferably acetonitrile. The molar volume ratio of the functional monomer to the organic solvent is 1 mmol:5-20 mL, preferably 1 mmol:6-19 mL, and more preferably 1 mmol:7-18 mL.

[0015] The prepolymerization process plays a key role in the preparation of molecular imprinting polymers: on the one hand, prepolymerization can connect monomer molecules into several chain molecules of different lengths, and act as a high molecular weight catalyst in the main polymerization link to increase the polymerization reaction rate, thereby improving the polymerization efficiency; on the other hand, prepolymerization can control the molecular weight, make the polymer molecular structure more complete and regular, improve the physical properties of the polymer, and improve the mechanical strength.

[0016] Preferably, in step (1), the temperature of the prepolymerization reaction is 15 to 25° C., further 16 to 24° C., further 18 to 23° C.; the time of the prepolymerization reaction is 8 to 14 h, further 9 to 13 h, further 10 to 12 h.

[0017] Preferably, the crosslinking agent includes epichlorohydrin, glutaraldehyde or N,N'-methylenebisacrylamide, and the initiator includes azobisisobutyronitrile.

[0018] More preferably, the crosslinking agent is epichlorohydrin or N,N'-methylenebisacrylamide; and the initiator is azobisisobutyronitrile.

[0019] Preferably, the molar ratio of the template molecule perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomer, the functional monomer and the cross-linking agent is 1:3-5:15-25, further 1:4:16-24; the amount of the initiator added is 2-5wt% of the total mass of the functional monomer and the cross-linking agent, further 3-4wt%.

[0020] Preferably, the inert gas atmosphere is a nitrogen atmosphere. In step (2), the polymerization reaction temperature is 50 to 80° C., further 55 to 75° C., and further 60 to 65° C.; the polymerization reaction time is 15 to 20 h, further 16 to 19 h, and further 17 to 18 h.

[0021] Specifically, after the solid in the product solution is separated, it is ground to 40-80 mesh, and further, it is ground to 50-70 mesh; the eluent is selected from at least one of water, methanol, acetic acid, and acetonitrile.

[0022] Preferably, the eluent is a mixed solution of methanol and acetic acid, with a volume ratio of 1:90-99; the volume mass ratio of the eluent to the ground polymer is 10-15 mL:1 g.

[0023] The present invention also provides a molecular imprinting polymer for adsorbing perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomers obtained by the preparation method of the molecular imprinting polymer.

[0024] The present invention also provides a chromatography column, wherein the filler of the chromatography column is the molecular imprinting polymer.

[0025] Preferably, the diameter-to-height ratio of the chromatography column is 1-8:10, further 1:8, and the volume of the molecular imprinted polymer is 100-150 mL, further 120-140 mL; when the chromatography column is used, the adsorption flow rate is maintained at 2-5 BV / h, further 3-4 BV / h, and the adsorption temperature is 15-30°C, further 18-28°C, and further 20-25°C.

[0026] The present invention also provides a method for separating isomers in crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride, using the molecular imprinting polymer or the chromatography column.

[0027] Furthermore, in the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride, the content of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride is 97-99wt%; the content of isomers is ≤2wt%. The crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride can be prepared according to the method described in the existing literature or purchased.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention prepares a molecular imprinting polymer by an in-situ polymerization method, and removes isomeric template molecules by steps such as grinding and elution. The molecular imprinting polymer is used for separation and purification of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride by virtue of its specific recognition and selective adsorption properties. The molecular imprinting polymer has a strong adsorption effect on the isomers of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride, thereby improving the accuracy of separation of isomers and further improving the purity and quality of the product.

[0030] (2) The method of the present invention can avoid the problems of product loss caused by the decomposition of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride and the generation of additional three wastes due to the temperature increase during purification by the existing distillation technology. At the same time, the adsorption saturated molecular imprinting polymer can be reused by elution and drying, which further achieves the cost reduction and efficiency improvement of the purification of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride, conforms to the development of green chemistry, and has great industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a scanning electron micrograph of the molecularly imprinted polymer prepared in Example 1;

[0032] Figure 2 is the infrared spectrum of the molecularly imprinted polymer prepared in Example 1;

[0033] Figure 3 The crude product of perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride used in the examples is 19 F NMR spectrum;

[0034] Figure 4 is the mass spectrum of the crude product of perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride used in the examples;

[0035] Figure 5 This is a statistical graph of the adsorption data of the molecular imprinting polymer prepared in Example 1 on isomers in the crude product of perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride. DETAILED DESCRIPTION

[0036] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description through specific embodiments. In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0037] The operating methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. The contents not described in detail in this specification belong to the prior art known to professionals in the field. The experimental materials used in the following examples, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0038] The preparation method of a molecularly imprinted polymer for adsorbing perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomers specifically comprises the following steps:

[0039] (1) mixing the template molecule perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomer and the functional monomer in an organic solvent for prepolymerization to obtain a template-monomer mixed solution;

[0040] (2) adding a crosslinking agent and an initiator to the template-monomer mixture, heating the mixture under an inert gas atmosphere for polymerization, and after the reaction is completed, sequentially subjecting the obtained product solution to solid-liquid separation, grinding and elution to obtain the molecularly imprinted polymer.

[0041] Furthermore, the molecularly imprinted polymer is filled in a chromatography column to selectively adsorb the isomers in the crude perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride.

[0042] The template molecule perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomers can be obtained by distilling a crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product and separating it by chromatography. The crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product is prepared according to the method in patent CN114773239A. In the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product, the content of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride is 98wt%, and the content of isomers is 1.95wt%.

[0043] Example 1

[0044] 5mmol perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomer and 20mmol methyl methacrylate were dissolved in 150mL acetonitrile and prepolymerized at 25℃ for 12h to obtain a template-monomer mixture; 110mmol N,N'-methylenebisacrylamide and 0.75g azobisisobutyronitrile were added to the template-monomer mixture, the solution was mixed evenly by ultrasound, nitrogen was blown to remove oxygen, and the mixture was placed in a 60℃ constant temperature water bath for 18h. After the reaction was completed, the obtained product solution was separated from the solid and liquid, and the solid polymer was ground to 50-70 mesh. A methanol-acetic acid mixed solution with a volume ratio of 1:99 was used as an eluent for elution. The eluent dosage was 10mL / g. After elution, the mixture was dried at room temperature to obtain the molecular imprinting polymer. The SEM image of the molecular imprinting polymer is shown in the figure below: Figure 1 As shown in the figure, the surface of the molecularly imprinted polymer shows a porous structure, roughness and obvious imprinted cavities. Figure 2 As shown, at 1550cm -1There is an amino vibration absorption peak at 3436cm -1 The O-H bond vibration absorption peak appeared at 1431 cm -1 、880cm -1 The vibration absorption peak caused by the C-H bond appears at 1667cm -1 The stretching vibration absorption peak caused by C=O appears at , indicating that the molecular imprinted polymer was successfully synthesized.

[0045] 120 mL of the prepared molecularly imprinted polymer was loaded into a chromatography column with a diameter-to-height ratio of 1:8, and the isomers in the crude perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride were adsorbed at 20° C. with an adsorption flow rate of 4 BV / h. Figure 3 and Figure 4 They are the corresponding crude perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride. 19 F NMR spectra and mass spectra.

[0046] Figure 5 This is the adsorption data of the molecular imprinting polymer prepared in this example on the isomers in the crude perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride. After adsorbing 500 mL of the crude perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride for 50 minutes, the product purity increased to 99.93%.

[0047] Example 2

[0048] 5mmol of perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomer and 25mmol of methyl methacrylate were dissolved in 130mL of acetonitrile, and prepolymerized at 20°C for 10h to obtain a template-monomer mixture; 100mmol of N,N'-methylenebisacrylamide and 0.6g of azobisisobutyronitrile were added to the template-monomer mixture, and the solution was mixed evenly by ultrasound, and nitrogen was blown to remove oxygen, and the mixture was placed in a constant temperature water bath at 65°C for polymerization for 20h. After the reaction was completed, the obtained product solution was subjected to solid-liquid separation, and the solid polymer was ground into 60-80 meshes, and eluted with a methanol-acetic acid mixed solution with a volume ratio of 1:90 as an eluent, and the eluent dosage was 12mL / g. After elution, the mixture was dried at room temperature to obtain the molecularly imprinted polymer.

[0049] 120 mL of the prepared molecularly imprinted polymer was taken and loaded into a chromatography column with a diameter-to-height ratio of 1:8. The isomers in the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride were adsorbed at 25°C with an adsorption flow rate of 3 BV / h. After adsorbing 500 mL of the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride for 60 minutes, the purity of the product was 99.90%.

[0050] Example 3

[0051] 6mmol perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomer and 18mmol methyl methacrylate were dissolved in 120mL acetonitrile, and prepolymerized at 22°C for 8h to obtain a template-monomer mixture; 150mmol N,N'-methylenebisacrylamide and 1.2g azobisisobutyronitrile were added to the template-monomer mixture, and the solution was mixed evenly by ultrasound, and nitrogen was blown to remove oxygen, and the mixture was placed in a constant temperature water bath at 70°C for polymerization for 16h. After the reaction was completed, the obtained product solution was subjected to solid-liquid separation, and the solid polymer was ground into 40-60 meshes, and eluted with a methanol-acetic acid mixed solution with a volume ratio of 1:95 as an eluent, and the eluent amount was 15mL / g. After elution, the mixture was dried at room temperature to obtain the molecular imprinting polymer.

[0052] 140 mL of the prepared molecularly imprinted polymer was taken and loaded into a chromatography column with a diameter-to-height ratio of 1:10. The isomers in the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride were adsorbed at a temperature of 25°C. The adsorption flow rate was 5 BV / h. After adsorbing 500 mL of the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride for 60 minutes, the purity of the product obtained was 99.91%.

[0053] Comparative Example 1

[0054] 5mmol perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomer and 20mmol methyl methacrylate were dissolved in 150mL acetonitrile, stirred evenly, and then 110mmol N,N'-methylenebisacrylamide and 0.75g azobisisobutyronitrile were added. The solution was mixed evenly by ultrasound, and nitrogen was blown to remove oxygen. The solution was placed in a constant temperature water bath at 60°C and heated for polymerization for 18h. After the reaction was completed, the obtained product solution was separated from the solid and liquid, and the solid polymer was ground into 50-70 meshes. A methanol-acetic acid mixed solution with a volume ratio of 1:99 was used as an eluent for elution. The amount of the eluent was 10mL / g, and the solution was dried at room temperature after elution.

[0055] 120 mL of the prepared molecularly imprinted polymer was loaded into a chromatography column with a diameter-to-height ratio of 1:8, and the isomers in the crude perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride were adsorbed at 20° C. with an adsorption flow rate of 4 BV / h.

[0056] After adsorbing 500 mL of crude perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride for 50 minutes, the product purity increased to 98.62%, indicating that without the prepolymerization step, the adsorption performance of the molecularly imprinted polymer obtained could not meet the product performance requirements.

[0057] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a molecularly imprinted polymer for adsorbing perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomers, characterized in that: The following steps are involved: (1) mixing the template molecule perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride isomer and the functional monomer in an organic solvent for prepolymerization to obtain a template-monomer mixed solution; (2) adding a crosslinking agent and an initiator to the template-monomer mixture, heating the mixture under an inert gas atmosphere for polymerization, and after the reaction is completed, sequentially performing solid-liquid separation, grinding and elution on the obtained product solution to obtain the molecularly imprinted polymer; The structural formula of the template molecule perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomer is FSO2CF2CF2O CF2CF(CF3)OCF=CF2; Functional monomers include methacrylic acid, methyl methacrylate, acrylamide or 2-vinylpyridine.

2. The method for preparing a molecularly imprinted polymer according to claim 1, characterized in that: The functional monomer is methyl methacrylate and / or acrylamide; the molar ratio of the template molecule perfluoro (4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride isomer to the functional monomer is 1:3-5.

3. The method for preparing a molecularly imprinted polymer according to claim 1, characterized in that: The organic solvent comprises at least one of methanol, ethanol, acetonitrile and dichloromethane; the molar volume ratio of the functional monomer to the organic solvent is 1mmol:5-20mL.

4. The method for preparing a molecularly imprinted polymer according to claim 1, characterized in that: In step (1), the prepolymerization reaction temperature is 15 to 25° C., and the prepolymerization reaction time is 8 to 14 hours.

5. The method for preparing a molecularly imprinted polymer according to claim 1, characterized in that: The crosslinking agent includes epichlorohydrin, glutaraldehyde or N,N'-methylenebisacrylamide, and the initiator includes azobisisobutyronitrile; the molar ratio of the template molecule perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomer, the functional monomer and the crosslinking agent is 1:3-5:15-25; and the added amount of the initiator is 2-5wt% of the total mass of the functional monomer and the crosslinking agent.

6. The method for preparing a molecularly imprinted polymer according to claim 1, characterized in that: The inert gas atmosphere is a nitrogen atmosphere. In step (2), the polymerization reaction temperature is 50 to 80° C., and the polymerization reaction time is 15 to 20 hours.

7. The method for preparing a molecularly imprinted polymer according to claim 1, characterized in that: After the solid in the product solution is separated, it is ground to 40-80 mesh; the eluent is selected from at least one of water, methanol, acetic acid and acetonitrile.

8. A molecularly imprinted polymer for adsorbing perfluoro(4-methyl-3,6-dioxa-7-octenyl)sulfonyl fluoride isomers obtained according to the preparation method of the molecularly imprinted polymer according to any one of claims 1 to 7.

9. A chromatography column, characterized in that The filler of the chromatography column is the molecularly imprinted polymer according to claim 8.

10. The chromatography column according to claim 9, characterized in that The diameter-to-height ratio of the chromatography column is 1-8:10, and the volume of the molecular imprinted polymer is 100-150 mL. When the chromatography column is used, the adsorption flow rate is maintained at 2-5 BV / h and the adsorption temperature is maintained at 15-30°C.

11. A method for separating isomers in crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride, characterized in that: Utilize the molecularly imprinted polymer according to claim 8 or the chromatography column according to claim 9 or 10.

12. The method according to claim 11, wherein the content of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride in the crude product is 97-99wt%; and the content of isomers is ≤2wt%.

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