Process for the isolation and purification of perfluoro(4-methyl-3,6-dioxa-7- octene)sulfonyl fluoride

Abstract

The application relates to the field of organic matter separation, and discloses a method for separating and purifying perfluoro (4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride. The method comprises the following steps: (1) performing silica gel column chromatography on perfluoro (4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product in the presence of an external magnetic field; and (2) performing low-temperature desolubilization on the solution obtained by elution of the silica gel column chromatography; and the magnetic induction intensity of the external magnetic field is 0.5-2 T. The method utilizes the external magnetic field and the silica gel column chromatography to purify and separate the perfluoro (4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product, further improves the purity of the perfluoro (4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride obtained by purification, and can also reduce the energy consumption of the purification and separation, greatly improving the product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of organic matter separation, in particular to a method for separating and purifying perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride. BACKGROUND

[0002] Perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride (PSVE for short) was first developed in the 1970s and has been widely used. It has excellent heat resistance, mechanical properties, electrochemical properties, and chemical stability, and is widely used in chlor-alkali industry and fuel cell industry. In addition, perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride is also an important comonomer of a widely used high molecular fluorine material. Copolymerization with other monomers can produce fluororesin, fluorine rubber and other materials with special functions under specific conditions, and is essential for the preparation of perfluorosulfonic acid ion exchange resin. Its main role is to introduce functional sulfonic acid groups into the polymer, and it is a chemical with wide application range and high economic value.

[0003] At present, there are many reports on the synthesis of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride. The main methods are sulfonyl fluorination and pyrolytic decarboxylation. Patent application CN105753742A, patent CN108863854B, US patent US7005545B, Korean patent KR101956826B1, US patent application US3560568A and Chinese patent CN112250603A all disclose methods for synthesizing perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride. However, the perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product prepared by the current common preparation method usually contains various difficult-to-separate impurities, and the quality requirement of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride used in high polymerization reaction is extremely high (purity ≥ 99.9%).

[0004] However, the current method for separating and purifying perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product usually uses the common method of rectification for separation. Not only is the energy consumption high, but also since perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride is a heat-sensitive substance, long-term exposure to high-temperature systems will cause decomposition of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride, resulting in large loss of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride in the product, and a large amount of "three wastes" generated during purification, further increasing the cost of separation and purification. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art, such as high energy consumption, product decomposition, heavy pollution, and insufficient purity of the purified perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride product, and to provide a method for separating and purifying perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride. The method uses an external magnetic field and silica gel column chromatography to purify and separate perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride, further improving the purity of the purified perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride, and also reducing the energy consumption of the purification and separation, greatly improving the quality of the product.

[0006] To achieve the above-mentioned purpose, the present application provides a method for separating and purifying perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride, which comprises:

[0007] (1) performing silica gel column chromatography on perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product in the presence of an external magnetic field;

[0008] (2) performing low-temperature desolventization on the solution eluted by the silica gel column chromatography;

[0009] The magnetic induction intensity of the external magnetic field is 0.5-2T.

[0010] Preferably, the content of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride in the perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product is 95-99wt%.

[0011] Preferably, the content of hydrogen-containing compounds in the perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product is ≤3%, and the content of isomers is ≤2%.

[0012] Preferably, the eluent used in the elution in the silica gel column chromatography contains hydrofluoroether;

[0013] Preferably, the eluent is a mixed solution of hydrofluoroether and C5-C10 alkane.

[0014] Preferably, the particle size of the silica gel in the chromatographic silica gel column used in the silica gel column chromatography is 400-600 mesh.

[0015] Preferably, the weight ratio of the amount of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product to the amount of silica gel is 1:4-7.

[0016] Preferably, the volume ratio of hydrofluoroether to C5-C10 alkane in the eluent is 5-20:1.

[0017] Preferably, the length-diameter ratio of the chromatographic silica gel column is 8-12:1.

[0018] Preferably, the temperature of the low-temperature desolventization is 20-60°C.

[0019] Preferably, the external magnetic field is provided by a permanent magnet or an electromagnet.

[0020] In the method described in the present application, when the crude perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride is separated and purified by silica gel column chromatography, the polarity difference between the perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride and other impurities in the crude product can be significantly increased by applying a magnetic field, and the perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride can be more easily separated and purified, thereby improving the purity of the perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride obtained by separation and improving the product quality.

[0021] In addition, the method described in the present application does not require heating and other conditions, and the energy consumption of separation and purification is lower, and the problem of decomposition of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride caused by purification by rectification and other methods in the prior art can be completely avoided, the yield of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride is maximized, and additional "three wastes" treatment is avoided, further realizing low-cost and environmentally friendly and pollution-free purification of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride, which meets the green development direction, and is simple to operate, and has great industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of a specific embodiment of the present application;

[0023] Figure 2 is a mass spectrum of the crude perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride used in the example. 19 F NMR spectrum;

[0024] Figure 3 is a mass spectrum of the crude perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride used in the example. DETAILED DESCRIPTION

[0025] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the present application, and are not intended to limit the present application.

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] This invention provides a method for separating and purifying perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride, the method comprising:

[0028] (1) Crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride was subjected to silica gel column chromatography in the presence of an external magnetic field;

[0029] (2) The solution obtained by silica gel column chromatography is subjected to low-temperature desolvation.

[0030] In the method described in this invention, the inventors have creatively discovered that when crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride is subjected to silica gel column chromatography in the presence of an external magnetic field, the polarity difference between the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride and other impurities becomes larger under the influence of the external magnetic field. This makes it easier to separate the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride from other impurities during silica gel column chromatography, resulting in a higher purity of the purified perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product. This makes it more suitable for use in polymer polymerization and the preparation of other types of chemicals. Furthermore, the method described in this invention can purify and separate perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride using only an external magnetic field and silica gel column chromatography, eliminating the need for heating treatment of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride. This avoids the problem of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride decomposition caused by high temperatures, ensuring the yield of purified perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride. It also avoids the toxic waste gases generated by the thermal decomposition of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride. The entire purification and separation process is more environmentally friendly and safer, with lower energy consumption, further saving the cost of purifying and separating perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride.

[0031] In the method of the present application, in order to further ensure the purity of the purified perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product, the magnetic induction intensity of the external magnetic field is limited to 0.5-2T, preferably 1-1.5T. Specifically, the magnetic induction intensity of the external magnetic field can be 0.5T, 1T, 1.5T or 2T. In the method of the present application, when the magnetic induction intensity of the set external magnetic field is too large or too small, it will not significantly improve the polarity difference between perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride and other impurities, resulting in low purification separation efficiency, and even reducing the purity of the final perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product. Therefore, in the method of the present application, the magnetic induction intensity of the external magnetic field needs to be set within the range limited by the present application.

[0032] In a specific embodiment, the external magnetic field can be provided by a permanent magnet or an electromagnet. The specific provision method can refer to conventional prior art in the art, which will not be described here.

[0033] In the method of the present application, the source of the perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride crude product is not limited, which can be a crude product prepared according to the conventional perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride preparation method in the art. Specifically, the perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride crude product can be prepared according to the method in patent application CN 114773239A.

[0034] In a preferred embodiment, the perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride crude product contains ≤3% hydrogen-containing compounds and ≤2% isomers. In the present application, the hydrogen-containing compound refers to all substances containing hydrogen atoms in the structure of the perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride crude product, and the isomer refers to the isomer of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride.

[0035] In the method of the present application, the content of perfluoro(4-methyl-3,6-dioxa-7- octene)sulfonyl fluoride in the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride is not limited. Further, in order to ensure the purity of the final perfluoro(4-methyl-3,6-dioxa-7- octene)sulfonyl fluoride product, the content of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride in the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride is limited to 95-99 wt%. Specifically, the content of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride in the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride can be 95 wt%, 96 wt%, 97 wt%, 98 wt% or 99 wt%.

[0036] In a specific embodiment, the silica gel column chromatography is performed using a chromatography silica gel column, which can be packed according to conventional techniques in the art.

[0037] In a specific embodiment, the step (1) is performed by packing the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride into a chromatography silica gel column in the presence of an applied magnetic field, performing silica gel column chromatography, eluting with an eluent, and collecting the eluted solution. The step (1) can be performed according to the method described in Figure 1 .

[0038] In the method of the present application, the eluent specifically refers to the mobile phase used to elute the chromatography silica gel column in the silica gel column chromatography.

[0039] In a preferred embodiment, in order to further ensure the purity of the purified perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride, the eluent used to elute in the silica gel column chromatography contains hydrofluoroether. The hydrofluoroether used in the present application has a structure similar to that of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride and has better solubility for perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride. Further, by adding C5-C10 alkane to adjust the polarity of the eluent, perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride can be specifically separated from other impurities, thereby ensuring the purity of the final product.

[0040] In a preferred embodiment, the eluent is a mixed solution of hydrofluoroether and C5-C10 alkane. Specifically, the C5-C10 alkane is selected from one or more than two of pentane, hexane, heptane, octane, nonane and decane. The use of the mixed solution of hydrofluoroether and C5-C10 alkane as the eluent for the silica gel column chromatography can ensure better separation of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride.

[0041] In a preferred embodiment, the volume ratio of hydrofluoroether to C5-C10 alkane in the eluent is 5-20:1, preferably 12-17:1.

[0042] In a preferred embodiment, the particle size of the silica gel in the chromatographic silica gel column used in the silica gel column chromatography is 400-600 mesh. Specifically, the particle size of the silica gel can be 400 mesh, 500 mesh or 600 mesh.

[0043] In a preferred embodiment, in order to further separate perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride and other impurities in the crude product, the weight ratio of the amount of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product to silica gel is limited to 1:4-7 when performing silica gel column chromatography. Specifically, the weight ratio of the amount of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride crude product to silica gel can be 1:4, 1:5, 1:6 or 1:7.

[0044] In the method described in the present application, the length-diameter ratio of the chromatographic silica gel column is 8-12:1. Specifically, the length-diameter ratio of the chromatographic silica gel column can be 8:1, 9:1, 10:1, 11:1 or 12:1.

[0045] In a specific embodiment, the solution obtained after elution with the eluent is collected, and then low-temperature desolventization is performed to obtain the purified perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride product after washing and drying the obtained solid phase.

[0046] In the method described in the present application, in order to avoid the decomposition of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride in the product, low-temperature desolventization is used to precipitate perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride from the eluent. The low-temperature desolventization method can be implemented according to the conventional prior art in the field, and specifically, the low-temperature desolventization method can be reduced pressure rotary evaporation.

[0047] In a preferred embodiment, the temperature of the low-temperature desolventization is 20℃-60℃.

[0048] The present application will be described in detail below through examples, but the scope of protection of the present application is not limited thereto.

[0049] In the following examples, the experimental methods are conventional methods in the field unless otherwise specified. The experimental materials used in the following examples are commercially available unless otherwise specified.

[0050] The crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride used in the following examples and comparative examples was prepared according to the method of patent application CN 114773239A. 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 was 95%, the content of hydrogen-containing compounds was 3%, and the content of isomers was 2%.

[0051] In the following examples, the method of low-temperature desolventization used was reduced pressure rotary evaporation.

[0052] Example 1

[0053] (1) In the presence of an applied magnetic field (magnetic induction intensity of 0.5 T), 50 g of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride (purity of 95.0%) was packed into a chromatographic silica gel column (silica gel mesh size of 600 mesh) for silica gel column chromatography (weight ratio of the use amount of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride to silica gel was 1:4, and the length-diameter ratio of the chromatographic silica gel column was 8:1), and a hydrogen fluoride ether-decane mixed solution with a volume ratio of 5:1 was used as an eluent for elution, and the solution obtained after elution was collected;

[0054] (2) The eluted solution was subjected to low-temperature desolventization at a temperature of 35°C, and then the desolventized solid phase was washed with clean water for 3 times and dried to obtain 45 g of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product (purity of 99.90%).

[0055] Example 2

[0056] (1) In the presence of an applied magnetic field (magnetic induction intensity of 1.0 T), 120 g of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride was packed into a chromatographic silica gel column (silica gel mesh size of 400 mesh) for silica gel column chromatography (weight ratio of the use amount of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride to silica gel was 1:4, and the length-diameter ratio of the chromatographic silica gel column was 10:1), and a hydrogen fluoride ether-decane mixed solution with a volume ratio of 20:1 was used as an eluent for elution, and the solution obtained after elution was collected;

[0057] (2) The eluted solution was subjected to low-temperature desolventization at a temperature of 40°C, and then the desolventized solid phase was washed with clean water for 3 times and dried to obtain 105 g of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product (purity of 99.93%).

[0058] Example 3

[0059] (1) In the presence of an applied magnetic field (magnetic induction intensity of 2T), 80 g of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride was packed into a chromatographic silica gel column (the silica gel mesh size was 500 mesh) for silica gel column chromatography (the weight ratio of the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride to the silica gel was 1:7, and the length-diameter ratio of the chromatographic silica gel column was 12:1), and a hydrogen fluoride ether-pentane mixed solution with a volume ratio of 15:1 was used as an eluent for elution, and the solution obtained after elution was collected;

[0060] (2) The eluted solution was subjected to low-temperature desolubilization at a temperature of 45°C, and then the desolubilized solid phase was washed with clean water for 3 times and dried to obtain 76 g of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product (the purity was 99.94%).

[0061] Example 4

[0062] (1) In the presence of an applied magnetic field (magnetic induction intensity of 1.5T), 60 g of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride was packed into a chromatographic silica gel column (the silica gel mesh size was 400 mesh) for silica gel column chromatography (the weight ratio of the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride to the silica gel was 1:5, and the length-diameter ratio of the chromatographic silica gel column was 12:1), and a hydrogen fluoride ether-octane mixed solution with a volume ratio of 10:1 was used as an eluent for elution, and the solution obtained after elution was collected;

[0063] (2) The eluted solution was subjected to low-temperature desolubilization at a temperature of 40°C, and then the desolubilized solid phase was washed with clean water for 3 times and dried to obtain 53 g of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product (the purity was 99.90%).

[0064] Comparative Example 1

[0065] The method of Example 1 was implemented, except that no applied magnetic field was set, and silica gel column chromatography was directly performed to obtain 40 g of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product (the purity was 97.23%).

[0066] Comparative Example 2

[0067] The method of Example 3 was implemented, except that no applied magnetic field was set, and silica gel column chromatography was directly performed to obtain 65 g of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product (the purity was 97.14%).

[0068] Comparative Example 3

[0069] The method of Example 4 was carried out, except that the magnetic induction intensity of the external magnetic field was set to be 0.3T, and 48g of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride product (purity of 98.91%) was obtained.

[0070] Comparative Example 4

[0071] The method of Example 4 was carried out, except that the magnetic induction intensity of the external magnetic field was set to be 2.5T, and 46g of perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride product (purity of 98.43%) was obtained.

[0072] Comparative Example 5

[0073] 500g of crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride was purified by distillation. The distillation column had a diameter of 35mm, 40 trays, a top temperature of 62℃~63℃, a vacuum of 0.095MPa, and a distillation time of 46h. After the distillation, 320g of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product (purity of 99.16%) was obtained.

[0074] Test case

[0075] Test Example 1

[0076] The crude perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride used in the examples and comparative examples was subjected to... 19 F NMR and mass spectrometry (MS) tests were performed, and the results are as follows: Figure 2 and Figure 3 As shown. According to 19 The chemical shifts (-SO2F: 43.18 ppm; =CF2: 86.37 ppm, 86.48 ppm) in the F NMR spectrum and the mass spectrometry fragmentation results indicate that the crude product does indeed contain perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride.

[0077] Test Example 2

[0078] The purity of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride products obtained by the final purification in Examples 1-4 and Comparative Examples 1-5 was tested by gas chromatography, and the results are shown in Table 1.

[0079] The yield of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride in Examples 1-4 and Comparative Examples 1-5 was calculated according to the purity of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride obtained by testing, according to the formula: (M2 x a2) ÷ (M1 x a1) x 100%, wherein M1 is the weight of the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride, and a1 is the content of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride in the crude perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride; M2 is the weight of the final recovered perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product, and a2 is the purity of the perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride product. The results are shown in Table 1.

[0080] Table 1

[0081] Example No. Purity of PSVE in product (%) Yield of PSVE (%) Example 1 99.90 94.6 Example 2 99.93 92 Example 3 99.94 99.94 Example 4 99.90 92.89 Comparative Example 1 97.23 81.8 Comparative Example 2 97.14 83 Comparative Example 3 98.91 83.2 Comparative Example 4 98.43 79.43 Comparative Example 5 99.16 66.8

[0082] As can be seen from the results in Table 1, the method described in the present application can be used to separate and purify perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride products with a purity of greater than 99.9%, and the yield of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride is high, no heating is required, the loss of perfluoro(4-methyl-3,6-dioxa-7-octene)sulfonyl fluoride is small, the purification and separation process is simple, and is more in line with the concept of green environmental protection, and has a broad application prospect.

[0083] The preferred embodiments of the present application have been described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. A method for the isolation and purification of perfluoro(4-methyl-3,6-dioxa-7- octene)sulfonyl fluoride, characterized in that, The method comprises: (1) performing silica gel column chromatography on crude perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride in the presence of an applied magnetic field; (2) performing low-temperature desolventization on the solution eluted from the silica gel column chromatography; The magnetic induction intensity of the applied magnetic field is 0.5-2T; in the silica gel column chromatography, the eluent used for elution is a mixed solution of hydrofluoroether and C5-C10 alkane, and the volume ratio of hydrofluoroether to C5-C10 alkane in the eluent is 5-20:

1.

2. The method of isolating and purifying perfluoro(4-methyl-3,6-dioxa-7- octenyl)sulfonyl fluoride according to claim 1, characterized in that, 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 95-99wt%.

3. The method of isolating and purifying perfluoro(4-methyl-3,6-dioxa-7- octenyl)sulfonyl fluoride according to claim 1 or 2, characterized in that, The content of hydrogen-containing compounds in the crude perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride is ≤3wt%, and the content of isomers is ≤2wt%.

4. The method of isolating and purifying perfluoro(4-methyl-3,6-dioxa-7- octenyl)sulfonyl fluoride according to claim 1, characterized in that, In the chromatographic silica gel column used in the silica gel column chromatography, the particle size of silica gel is 400-600 mesh.

5. The method of isolating and purifying perfluoro(4-methyl-3,6-dioxa-7- octenyl)sulfonyl fluoride according to claim 4, characterized in that, The weight ratio of the amount of crude perfluoro(4-methyl-3,6-dioxa-7-octene) sulfonyl fluoride to the amount of silica gel is 1:4-7.

6. The method of isolating and purifying perfluoro(4-methyl-3,6-dioxa-7- octenyl)sulfonyl fluoride according to claim 4, characterized in that, The length-diameter ratio of the chromatographic silica gel column is 8-12:

1.

7. The method of isolating and purifying perfluoro(4-methyl-3,6-dioxa-7- octenyl)sulfonyl fluoride according to claim 1, characterized in that, The temperature of the low-temperature desolventization is 20-60℃.

8. The method of isolating and purifying perfluoro(4-methyl-3,6-dioxa-7- octenyl)sulfonyl fluoride according to claim 1, characterized in that, The applied magnetic field is provided by a permanent magnet or an electromagnet.

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