A method for preparing vinyl trisulfate

Abstract

This invention belongs to the field of new energy batteries, specifically relating to a method for preparing ethylene trisulfate. The preparation method includes the following steps: 1) adding a hexahydrin to an organic mixed solvent A containing the compound of formula I at a temperature ≤10℃, and reacting under controlled temperature to obtain a crude product; 2) concentrating the crude product obtained in step 1) under reduced pressure to remove the organic mixed solvent A, adding organic solvent B for slurrying, and crystallizing with organic solvent C to obtain ethylene trisulfate as shown in formula II. This invention's preparation method does not require an oxidation reaction to obtain the target product; the reaction is mild, the operation is simple, the cost is low, and it is environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of new energy batteries, and specifically relates to a method for preparing ethylene trisulfate. Background Technology

[0002] Against the backdrop of the accelerated iteration of the global new energy industry, the improvement of energy density, cycle life, and safety performance of power batteries, as a core component of new energy vehicles and energy storage systems, has become crucial for industry competition. Power batteries consist of four core components: positive electrode, negative electrode, electrolyte, and separator. Among them, the electrolyte, as the "blood of the battery," plays a vital role in ion conduction. Electrolyte additives, as key functional components, although added in only 1%-5% of the total electrolyte volume, can significantly optimize the stability of the electrode / electrolyte interface, suppress side reactions, and significantly improve the overall performance of the battery.

[0003] Currently, electrolyte additives have formed a diversified classification system, including film-forming additives, flame-retardant additives, conductive additives, and hydrolysis-resistant additives. Among them, film-forming additives have become the most core category of additives because they can build a stable solid electrolyte interphase (SEI) film on the electrode surface. DTD (ethylene sulfate), as a representative product of cyclic sulfate film-forming additives, has gained widespread attention in fields such as lithium-ion batteries and sodium-ion batteries due to its excellent SEI film regulation capabilities, becoming an important support for the upgrading of new energy battery technology.

[0004] As basic DTD technology matures, the development of DTD derivatives has become a technological hotspot to meet the performance requirements of next-generation batteries, such as high voltage, fast charging, and wide temperature range. Among them, 2-DTD (ethylene disulfate) and 3-DTD (ethylene trisulfate), as representative products of structural derivation, are gradually entering the research field. Compared with the basic 1-DTD (ethylene monosulfate) which is prone to decomposition at high voltage (>4.5V), 2-DTD (ethylene disulfate) improves oxidation stability by 20% and has a longer cycle life through its dual-ring structure design. 3-DTD (ethylene trisulfate) shows even more groundbreaking potential advantages, which can further improve battery stability. Through its three core advantages of interface regulation, ion conduction, and environmental tolerance, it can better match the core requirements of next-generation batteries such as high energy density, fast charging, long life, and wide temperature range.

[0005] However, existing industrial methods for the synthesis of 3-DTD (ethylene trisulfate) have significant shortcomings. They still employ a similar synthetic method to that of vinyl sulfate, where a diol or polyol is first reacted with thionyl chloride to obtain a vinyl sulfite intermediate, which is then catalytically oxidized using an oxidant such as sodium hypochlorite aqueous solution and a metal catalyst to produce vinyl sulfate or polycyclic vinyl sulfate. While this process is currently the mainstream industrial method and achieves the synthesis of the target molecule in two steps, the synthesis of vinyl sulfite often requires high temperatures to ensure a complete reaction, and this reaction is accompanied by the emission of large amounts of hydrogen chloride gas, causing air pollution and corrosive damage. Furthermore, the oxidation of vinyl sulfite to vinyl sulfate requires the addition of expensive catalysts such as ruthenium and rhodium, resulting in high costs that hinder large-scale industrial production. Additionally, the oxidant used is often a 7%-15% aqueous solution of sodium hypochlorite, requiring the addition of large amounts of sodium hypochlorite solution, and the reaction produces large amounts of wastewater containing catalysts and salts, causing potential environmental pollution.

[0006] To address the problems and shortcomings of existing preparation processes, this invention provides a method for preparing the target vinyl sulfate without an oxidation reaction. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for preparing ethylene trisulfate that can obtain the target product without oxidation reaction, and the reaction is mild, simple to operate, low in cost and environmentally friendly, thereby solving the problems in the prior art.

[0008] To achieve the above and other related objectives, the present invention is obtained through the following technical solution.

[0009] This invention provides a method for preparing ethylene trisulfate, the method comprising the following steps:

[0010] 1) At a temperature of ≤10℃, hexahydrol is added to organic mixed solvent A of the compound shown in Formula I, and the reaction is carried out under controlled temperature to obtain crude product;

[0011] 2) The crude product obtained in step 1) is concentrated under reduced pressure to remove organic mixed solution A, organic solvent B is added for pulping, and organic solvent C is added for crystallization to obtain ethylene trisulfate as shown in formula II;

[0012] .

[0013] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0014] This invention directly prepares the target vinyl trisulfate by reacting a hexahydrol with an activated compound of formula I [3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate]. Compared with the stepwise operation in the prior art, which uses thionyl chloride to react with a hexahydrol to first generate vinyl sulfite and then oxidize it to vinyl sulfate, this invention is more advantageous. It avoids the generation of volatile and corrosive hydrogen chloride gas, as well as the use of expensive metal catalysts and the generation of large amounts of wastewater after oxidation. It not only directly obtains the target product in one step, but also has the advantages of mild reaction, simple operation, low cost and environmental friendliness. Attached Figure Description

[0015] Figure 1 The 1H NMR spectrum of the vinyl trisulfate product in Example 1;

[0016] Figure 2 The carbon NMR spectrum of the vinyl trisulfate product in Example 1;

[0017] Figure 3 The image shows the single-crystal diffraction structure of the vinyl trisulfate product in Example 1. Detailed Implementation

[0018] The following describes in detail the embodiments of the method for preparing ethylene trisulfate provided by the present invention.

[0019] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0020] Through extensive research and exploration, the inventors of this invention have provided a method for preparing ethylene trisulfate. This method involves a mild reaction, can be completed at low temperatures, and does not produce volatile or corrosive gases such as hydrogen chloride, nor does it generate industrial wastewater containing metal catalysts and salts. It offers advantages such as a mild reaction, simple operation, low cost, and environmental friendliness. Based on this, this application has been completed.

[0021] Preparation method of vinyl trisulfate

[0022] This invention provides a method for preparing ethylene trisulfate, the method comprising the following steps:

[0023] 1) At a temperature of ≤10℃, hexahydrol is added to organic mixed solvent A of the compound shown in Formula I, and the reaction is carried out under controlled temperature to obtain crude product;

[0024] 2) The crude product obtained in step 1) is concentrated under reduced pressure to remove organic mixed solution A, organic solvent B is added for pulping, and organic solvent C is added for crystallization to obtain ethylene trisulfate as shown in formula II.

[0025] .

[0026] In the method for preparing ethylene trisulfate provided by this invention, step 1) involves adding a hexahydrol to an organic mixed solvent A containing the compound of formula I at a temperature ≤10°C, and reacting under controlled temperature to obtain the crude product. Specifically:

[0027] In step 1) of this invention, the hexahydrol is selected from mannitol, sorbitol, sweet alcohol, hexahydrol, cyclohexahydrol or its isomers.

[0028] In step 1) of this invention, the compound represented by Formula I is 3-(imidazolium-1-sulfonyl)-1-methyl-3H-imidazolium-1-onium trifluoromethanesulfonate, which can be synthesized and prepared by referring to existing disclosed techniques, such as the preparation method of the compound "3-(imidazolium-1-sulfonyl)-1-methyl-3H-imidazolium-1-onium trifluoromethanesulfonate" in Example I1 of the specification of patent WO2016172615A1, paragraphs 7-9 on page 8 and paragraph 1 on page 9.

[0029] In step 1) of this invention, the molar ratio of the compound shown in Formula I to the hexahydrol is 3 to 5:1 and any value between them or any range between two values, which can be selected as 3 to 4:1 or 4 to 5:1.

[0030] In step 1) of the present invention, further, in order to reduce the generation of intermolecular cross-linking byproducts in the reaction, the volume-to-weight ratio of the organic mixed solvent A to the hexahydrol is 5 to 20:1 and any value between them or any range between any two values, which can be selected as 5 to 10:1, 10 to 20:1, 10 to 15:1, or 15 to 20:1.

[0031] In step 1) of this invention, the organic mixed solvent A is a weakly polar aprotic mixed solvent. To avoid excessive sulfonation and the formation of intermolecular cross-linking byproducts during the reaction, and to improve the solubility of the material, the weakly polar aprotic mixed solvent is selected from at least two of dichloromethane, 1,2-dichloroethane, tetrahydrofuran, dioxane, ethylene glycol diethyl ether, or acetonitrile. Preferably, the organic mixed solvent A is selected from a combination of a first solvent and a second solvent, wherein the first solvent is selected from one of dichloromethane and 1,2-dichloroethane, and the second solvent is selected from one of tetrahydrofuran, dioxane, or ethylene glycol diethyl ether. Specifically, the organic mixed solvent A is selected from dichloromethane and tetrahydrofuran, dichloromethane and dioxane, dichloromethane and ethylene glycol diethyl ether, 1,2-dichloroethane and tetrahydrofuran, 1,2-dichloroethane and dioxane, or 1,2-dichloroethane and ethylene glycol diethyl ether.

[0032] In some embodiments, the volume ratio of the first solvent to the second solvent is 1:1 to 5, and can be selected as 1:1 to 2 or 1:2 to 5. For example, the volume ratio of dichloromethane to tetrahydrofuran is 1:1 to 5, and can be 1:1 to 2 or 1:2 to 5; the volume ratio of dichloromethane to dioxane is 1:1 to 5, and can be 1:1 to 2 or 1:2 to 5; the volume ratio of dichloromethane to ethylene glycol diethyl ether is 1:1 to 5, and can be 1:1 to 2 or 1:2 to 5; the volume ratio of 1,2-dichloroethane to tetrahydrofuran is 1:1 to 5, and can be 1:1 to 2 or 1:2 to 5; the volume ratio of 1,2-dichloroethane to dioxane is 1:1 to 5, and can be 1:1 to 2 or 1:2 to 5; the volume ratio of 1,2-dichloroethane to ethylene glycol diethyl ether is 1:1 to 5, and can be 1:1 to 2 or 1:2 to 5.

[0033] In step 1) of this invention, the hexahydrol is added to the organic mixed solvent A of the compound shown in Formula I at a temperature of -15~10℃ (optionally -15~-10℃, -10~10℃, -15~0℃, 0~10℃, 0~5℃, 5~10℃). The order of addition is that the hexahydrol is added slowly in batches to the organic mixed solvent A of the compound shown in Formula I. For example, the slow addition is done every 10 minutes, with each addition being 1 / 10 to 1 / 20 of the mass of the hexahydrol. Further, the chain-like hexahydrol contains two primary alcohols and four secondary alcohols. Slowly adding the hexahydrol to the organic mixed solvent A of the compound shown in Formula I allows the low concentration of the primary alcohol to preferentially react with the high concentration of 3-(imidazolium-1-sulfonyl)-1-methyl-3H-imidazolium-1-onium trifluoromethanesulfonate, thereby effectively avoiding intermolecular cross-linking side reactions.

[0034] In step 1) of this invention, the temperature-controlled reaction operation is as follows: the reaction is carried out at a low temperature of -15~10℃ for 30 min~1 h to allow the nucleophilic substitution reaction between the hexahydrol primary alcohol and 3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate to be complete, and then the temperature is raised to room temperature for 2 h~10 h to promote the cyclization reaction of the remaining secondary alcohol to obtain the final target ethylene trisulfate product crude product.

[0035] .

[0036] Furthermore, in the above temperature-controlled reaction, the low temperature can be selected as -15~-10℃, -10~10℃, -15~0℃, 0~10℃, 0~5℃, or 5~10℃, and the reaction time is 30min~45min or 45min~1h. In the room temperature reaction, the reaction time can be selected as 2h~5h or 5h~10h, etc.

[0037] In the preparation method of ethylene trisulfate provided by this invention, step 2) involves concentrating the crude product obtained in step 1) under reduced pressure to remove the organic mixed solution A, adding organic solvent B for pulping, and then crystallizing with organic solvent C to obtain ethylene trisulfate as shown in Formula II. Specifically:

[0038] In step 2) of this invention, the organic solvent B is selected from at least one of dichloromethane, 1,2-dichloroethane, ethyl acetate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, acetonitrile, acetone, N-methylpyrrolidone, methanol, ethanol, isopropanol, or methyl tert-butyl ether.

[0039] In step 2) of this invention, the pulping time is 0.5h to 2h. It can be selected as 0.5h to 1h or 1h to 2h.

[0040] In step 2) of this invention, the organic solvent C is selected from at least one of acetonitrile, dimethyl carbonate, diethyl carbonate, or methyl ethyl carbonate.

[0041] In step 2) of this invention, the ethylene trisulfate represented by formula II comprises monomers II-A to II-J or a mixture of at least two of the following configurations:

[0042] .

[0043] The beneficial effects of the present invention will be further illustrated below with reference to the embodiments.

[0044] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention is further described in detail below with reference to embodiments. However, it should be understood that the embodiments of this invention are merely for illustrative purposes and not for limiting the invention, and the embodiments are not limited to those given in the specification. Unless otherwise specified, specific experimental or operational conditions in the embodiments were prepared under conventional conditions or according to the conditions recommended by the material supplier.

[0045] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0046] In the following embodiments, unless otherwise specified, all the raw materials of the present invention are commercially available or prepared according to conventional methods in the art.

[0047] Example 1: Preparation of vinyl trisulfate (Formula II)

[0048] In a 500 mL reaction flask, at -10 °C, 2 g of mannitol (total 20 g, 109.8 mmol) was slowly added in 10 batches, with each batch spaced 10 minutes apart, to a mixed solvent of dichloromethane and tetrahydrofuran (300 mL, dichloromethane / tetrahydrofuran = 1:2) containing 127 g (351.3 mmol) of 3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate. After the addition was complete, the reaction was carried out at -10 °C for 40 minutes. Then the temperature was raised to room temperature and the reaction was carried out for 4 hours. After the reaction was completed, the solvent was removed by concentration under reduced pressure. The residue was added to ethyl acetate (100 mL) and stirred for 1 hour. The filtrate was removed by filtration, and the filter cake was collected to obtain a white crude target product. The crude product was dissolved in acetonitrile (200 mL) and heated to 40 °C. Then the temperature was lowered to 10 °C to crystallize. The crystals were collected by filtration to obtain 31 g of pure ethylene trisulfate, a pure white solid, with a yield of 76%.

[0049] The 1H NMR spectrum of the vinyl trisulfate product is as follows: Figure 1 As shown, 1 H NMR (400 MHz, Acetonitrile-d3) δ 5.51-5.45 (m, 2H), 5.42-5.37 (m, 2H), 5.04 (dd, J = 10.1,6.6 Hz, 2H), 4.86 (dd, J = 10.1, 4.7 Hz, 2H).

[0050] The carbon NMR spectrum of the vinyl trisulfate product is as follows: Figure 2 As shown, the single-crystal diffraction structure of the ethylene trisulfate product is as follows: Figure 3 As shown.

[0051] Example 2: Preparation of vinyl trisulfate (Formula II)

[0052] In a 500 mL reaction flask, at -10 °C, 2 g of sorbitol (total 20 g, 109.8 mmol) was slowly added in 10 batches, with each batch spaced 10 minutes apart, to a mixed solvent of dichloromethane and tetrahydrofuran (300 mL, dichloromethane / tetrahydrofuran = 1:2) containing 127 g (351.3 mmol) of 3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate. After the addition was complete, the reaction was carried out at -10 °C for 40 minutes. Then the temperature was raised to room temperature and the reaction was carried out for 4 hours. After the reaction was completed, the solvent was removed by concentration under reduced pressure. The residue was added to ethyl acetate (100 mL) and stirred for 1 hour. The filtrate was removed by filtration, and the filter cake was collected to obtain a white crude target product. The crude product was dissolved in acetonitrile (200 mL) and heated to 40 °C. Then the temperature was lowered to 10 °C to crystallize. The crystals were collected by filtration to obtain 28 g of pure ethylene trisulfate, a pure white solid, with a yield of 69%.

[0053] ¹H NMR (400 MHz, Acetonitrile-d3) δ 5.62-5.70 (m, 2H), 5.35-5.43 (m,2H), 5.15 (dd, J = 10.0, 6.2 Hz, 2H), 4.72 (dd, J = 10.0, 5.1 Hz, 2H).

[0054] Example 3: Preparation of vinyl trisulfate (Formula II)

[0055] In a 500 mL reaction flask, at -10 °C, 2 g of sweet alcohol (total 20 g, 109.8 mmol) was slowly added in 10 batches, with each batch spaced 10 minutes apart, to a mixed solvent of dichloromethane and tetrahydrofuran (300 mL, dichloromethane / tetrahydrofuran = 1:2) containing 127 g (351.3 mmol) of 3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate. After the addition was complete, the reaction was carried out at -10 °C for 40 minutes. Then the temperature was raised to room temperature and the reaction was carried out for 4 hours. After the reaction was completed, the solvent was removed by concentration under reduced pressure. The residue was added to ethyl acetate (100 mL) and stirred for 1 hour. The filtrate was removed by filtration, and the filter cake was collected to obtain a white crude target product. The crude product was dissolved in acetonitrile (200 mL) and heated to 40 °C. Then the temperature was lowered to 10 °C to crystallize. The crystals were collected by filtration to obtain 26 g of pure ethylene trisulfate, a pure white solid, with a yield of 64%.

[0056] ¹H NMR (400 MHz, Acetonitrile-d3) δ 5.58-5.65 (m, 2H), 5.28-5.36 (m,2H), 5.09 (dd, J = 10.1, 6.4 Hz, 2H), 4.78 (dd, J = 10.1, 4.9 Hz, 2H).

[0057] Example 4: Preparation of vinyl trisulfate (Formula II)

[0058] In a 500 mL reaction flask, at -10 °C, 2 g of mannitol (total 20 g, 109.8 mmol) was slowly added in 10 batches at 10-minute intervals to a mixed solvent of dichloromethane and dioxane (300 mL, dichloromethane / dioxane = 1:2) containing 127 g (351.3 mmol) of 3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate. After the addition was complete, the reaction was carried out at -10 °C for 40 minutes. Then the temperature was raised to room temperature and the reaction was carried out for 4 hours. After the reaction was completed, the solvent was removed by concentration under reduced pressure. The residue was added to ethyl acetate (100 mL) and stirred for 1 hour. The filtrate was removed by filtration, and the filter cake was collected to obtain a white crude target product. The crude product was dissolved in acetonitrile (200 mL) and heated to 40 °C. Then the temperature was lowered to 10 °C to crystallize. The crystals were collected by filtration to obtain 29 g of pure ethylene trisulfate, a pure white solid, with a yield of 71%.

[0059] 1 H NMR (400 MHz, Acetonitrile-d3) δ 5.51-5.45 (m, 2H), 5.42-5.37 (m,2H), 5.04 (dd, J = 10.1, 6.6 Hz, 2H), 4.86 (dd, J = 10.1, 4.7 Hz, 2H).

[0060] Example 5: Preparation of vinyl trisulfate (Formula II)

[0061] In a 500 mL reaction flask at -10 °C, 2 g of mannitol was slowly added in 10 batches, with each batch spaced 10 minutes apart, to a mixture of dichloromethane and ethylene glycol diethyl ether (300 mL, dichloromethane / ethylene glycol diethyl ether = 1:2) containing 3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate (127 g, 351.3 mmol), for a total of 20 g (109.8 mmol). After the addition was complete, the reaction was carried out at -10℃ for 40 minutes; then the temperature was raised to room temperature and the reaction was carried out for 4 hours. After the reaction was completed, the solvent was removed by concentration under reduced pressure. The residue was added to ethyl acetate (100 mL) and stirred for 1 hour. The filtrate was removed by filtration, and the filter cake was collected to obtain a white crude target product. The crude product was added to acetonitrile (200 mL) and heated to 40℃ to dissolve. Then the temperature was lowered to 10℃ to crystallize. The target product, ethylene trisulfate, was collected by filtration to obtain 28 g of pure white solid, with a yield of 69%.

[0062] 1H NMR (400 MHz, Acetonitrile-d3) δ 5.51-5.45 (m, 2H), 5.42-5.37 (m,2H), 5.04 (dd, J = 10.1, 6.6 Hz, 2H), 4.86 (dd, J = 10.1, 4.7 Hz, 2H).

[0063] Comparative Example 1: Preparation of vinyl trisulfate (Formula II)

[0064] In a 500 mL reaction flask, at -10 °C, 2 g of mannitol was slowly added in 10 batches, with each batch spaced 10 minutes apart, to a 300 mL dichloromethane solvent containing 127 g (351.3 mmol) of 3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate (total 20 g, 109.8 mmol). After the addition was complete, the reaction was carried out at -10 °C for 40 minutes. Then the temperature was raised to room temperature and the reaction was carried out for 4 hours. After the reaction was completed, the solvent was removed by concentration under reduced pressure. The residue was added to 100 mL of ethyl acetate and stirred for 1 hour. The filtrate was removed by filtration, and the filter cake was collected to obtain a white crude target product. The crude product was dissolved in 200 mL of acetonitrile and heated to 40 °C. Then the temperature was lowered to 10 °C to crystallize. The crystals were collected by filtration to obtain 21 g of pure ethylene trisulfate, a pure white solid, with a yield of 51%.

[0065] 1 H NMR (400 MHz, Acetonitrile-d3) δ 5.51-5.45 (m, 2H), 5.42-5.37 (m,2H), 5.04 (dd, J = 10.1, 6.6 Hz, 2H), 4.86 (dd, J = 10.1, 4.7 Hz, 2H).

[0066] Comparative Example 2: Preparation of Ethyl Trisulfate (Formula II)

[0067] In a 500 mL reaction flask, at -10 °C, 2 g of mannitol was slowly added in 10 batches, with each batch spaced 10 minutes apart, to a 300 mL tetrahydrofuran solvent containing 127 g (351.3 mmol) of 3-(imidazol-1-sulfonyl)-1-methyl-3H-imidazol-1-onium trifluoromethanesulfonate (total 20 g, 109.8 mmol). After the addition was complete, the reaction was carried out at -10 °C for 40 minutes. Then the temperature was raised to room temperature and the reaction was carried out for 4 hours. After the reaction was completed, the solvent was removed by concentration under reduced pressure. The residue was added to 100 mL of ethyl acetate and stirred for 1 hour. The filtrate was removed by filtration, and the filter cake was collected to obtain a white crude target product. The crude product was dissolved in 200 mL of acetonitrile and heated to 40 °C. Then the temperature was lowered to 10 °C to crystallize. The crystals were collected by filtration to obtain 24 g of pure ethylene trisulfate, a pure white solid, with a yield of 59%.

[0068] 1 H NMR (400 MHz, Acetonitrile-d3) δ 5.51-5.45 (m, 2H), 5.42-5.37 (m,2H), 5.04 (dd, J = 10.1, 6.6 Hz, 2H), 4.86 (dd, J = 10.1, 4.7 Hz, 2H).

[0069] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing ethylene trisulfate, characterized in that, The preparation method includes the following steps: 1) At a temperature of -15~10℃, add hexahydrol to the organic mixed solvent A of the compound shown in Formula I, adding it every 10 minutes, each time adding 1 / 10 to 1 / 20 of the mass of the hexahydrol added, and control the temperature to react to obtain the crude product. 2) The crude product obtained in step 1) is concentrated under reduced pressure to remove organic mixed solution A, organic solvent B is added for pulping, and organic solvent C is added for crystallization to obtain ethylene trisulfate as shown in formula II; In step 1), the organic mixed solvent A is a weakly polar aprotic mixed solvent; the organic mixed solvent A is selected from a combination of a first solvent and a second solvent, wherein the first solvent is selected from one of dichloromethane and 1,2-dichloroethane, and the second solvent is selected from one of tetrahydrofuran, dioxane, and ethylene glycol diethyl ether; the volume ratio of the first solvent and the second solvent is 1:1 to 5; the temperature-controlled reaction operation is as follows: reaction at -15 to 10℃ for 30 min to 1 h; reaction at room temperature for 2 h to 10 h; the hexahydrol is a chain hexahydrol; 。 2. The method for preparing ethylene trisulfate according to claim 1, characterized in that, In step 1), the hexahydrol is selected from one of mannitol, sorbitol, sweet alcohol, and hexahydrol.

3. The method for preparing ethylene trisulfate according to claim 1, characterized in that, Step 1) also includes one or more of the following conditions: A1) The molar ratio of the compound shown in Formula I to the hexahydrol is 3 to 5:1; A2) The volume-to-weight ratio of the organic mixed solvent A to the hexahydrol is 5 to 20:

1.

4. The method for preparing ethylene trisulfate according to claim 1, characterized in that, Step 2) also includes one or more of the following conditions: C1) The organic solvent B is selected from at least one of dichloromethane, 1,2-dichloroethane, ethyl acetate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, acetonitrile, acetone, N-methylpyrrolidone, methanol, ethanol, isopropanol or methyl tert-butyl ether. C2) The pulping time is 0.5h~2h.

5. The method for preparing ethylene trisulfate according to claim 1, characterized in that, In step 2), the organic solvent C is selected from at least one of acetonitrile, dimethyl carbonate, diethyl carbonate, or methyl ethyl carbonate.

6. The method for preparing ethylene trisulfate according to claim 1, characterized in that, In step 2), the vinyl trisulfate represented by formula II comprises monomers II-A to II-J with the following configurations, or a mixture of at least two of them: 。

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