A comprehensive preparation method of ethylene sulfate and ethylene sulfate prepared by the method

Abstract

This invention provides a comprehensive method for preparing vinyl sulfate and the vinyl sulfate obtained therefrom. The method includes: mixing bis(trimethylsilyl)sulfate, alkyl diol, a metal halide catalyst, and a first solvent; performing a first reaction to obtain catalyst residue, trimethylsilanol, and vinyl sulfate; and then reacting the catalyst residue with trimethylsilanol to recover hexamethyldisiloxane, which is used as a raw material for preparing bis(trimethylsilyl)sulfate. This comprehensive method provides vinyl sulfate, and the catalyst can be used in two ways, generating the byproduct hexamethyldisiloxane, which can be recycled and used as a raw material to react with sulfuric acid to prepare bis(trimethylsilyl)sulfate. This achieves material recycling, significantly reduces economic costs, greatly improves atom economy and the greenness of the process, and has certain feasibility in industrial production.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology and relates to a comprehensive preparation method of vinyl sulfate and the vinyl sulfate obtained therefrom. Background Technology

[0002] Vinyl sulfate (DTD) is a white crystalline powder with a melting point of 95°C to 97°C. It readily absorbs water and hydrolyzes in dry, humid air, exhibiting strong acidity. It is not completely stable to photothermal radiation. Vinyl sulfate is an SEI film-forming additive used in lithium-ion battery electrolytes to inhibit the decline in initial battery capacity, increase initial discharge capacity, reduce battery swelling after high-temperature storage, and improve charge-discharge performance and cycle life. The applications of vinyl sulfate are becoming increasingly widespread, and market demand is growing. Researching efficient and environmentally friendly synthetic routes for vinyl sulfate has significant commercial value. Currently, the main synthetic methods include acylation, substitution, direct addition, and oxidation methods, but all have some limitations.

[0003] CN109776487A discloses a method for preparing vinyl sulfate. The method uses ethylene glycol and sulfonyl chloride as starting materials and chloroform as solvent to obtain crude vinyl sulfate, which is then purified to obtain vinyl sulfate. However, the raw material sulfonyl chloride is a hazardous chemical with strong corrosiveness, which requires high qualifications for production equipment and operators. Furthermore, the reaction generates significant environmental pollution from waste, making it unsuitable for industrial production.

[0004] CN114539211A discloses a method for preparing vinyl sulfate, using ethylene oxide and halosulfonic acid as raw materials, employing an aprotic solvent as the reaction medium, and undergoing condensation reaction, cooling crystallization, and other treatments to obtain vinyl sulfate. The raw material used is ethylene oxide, which is flammable, explosive, and highly toxic, and requires high production conditions. Considering both process feasibility and cost, it is difficult to adopt this method.

[0005] CN109485633A discloses a method for preparing vinyl sulfate, using ethylene glycol as the starting material, which reacts with thionyl chloride to generate the intermediate vinyl sulfite. The intermediate vinyl sulfite is then oxidized with sodium hypochlorite and catalyzed by an aqueous solution of ruthenium trichloride. However, the precious metal catalyst ruthenium trichloride used is expensive and difficult to recycle. In addition, the excessive use of sodium hypochlorite as a strong oxidant results in a large amount of waste, including a large amount of saline wastewater, which has a significant impact on the environment.

[0006] Currently, the production cost of vinyl sulfate is high, it has a significant environmental impact, and its industrial feasibility is poor. Therefore, how to solve these problems is an urgent issue to be explored. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a comprehensive method for preparing vinyl sulfate and the vinyl sulfate obtained therefrom. The comprehensive preparation method provided by the present invention uses a metal halide as a catalyst in an organic system to perform an ester exchange cyclization reaction between bis(trimethylsilane) sulfate and an alkyl diol to obtain the vinyl sulfate. Simultaneously, the catalyst can be used in two ways, generating a byproduct hexamethyldisiloxane, which can be recycled and reused as a raw material to react with sulfuric acid to prepare bis(trimethylsilane) sulfate. This achieves material recycling, significantly saves economic costs, greatly improves atom economy and the greenness of the process, and has certain feasibility in industrial production.

[0008] To achieve this objective, the present invention employs the following technical solution:

[0009] In a first aspect, the present invention provides a comprehensive method for preparing vinyl sulfate, the method comprising the following steps:

[0010] A first reaction is carried out by mixing bis(trimethylsilyl)sulfate, alkyl diol, metal halide catalyst and first solvent to obtain catalyst residue, trimethylsilanol and vinyl sulfate; the catalyst residue is then reacted with trimethylsilanol to recover hexamethyldisiloxane, which is used as a raw material for the preparation of bis(trimethylsilyl)sulfate.

[0011] It should be noted that the catalyst residues in this invention include aluminum hydroxide, aluminum oxide, and other aluminum-containing solid or gel-like substances.

[0012] The comprehensive preparation method provided by this invention uses inexpensive and readily available metal halides as catalysts in an organic system, lowering the reaction temperature. It involves a transesterification cyclization reaction (first reaction) of bis(trimethylsilyl)sulfate and alkyl diol at low temperature to obtain the ethylene sulfate. Simultaneously, the catalyst can be used for two purposes, completing the two-step catalysis without the need for additional catalysts. In the second reaction, the catalyst residue is partially converted into active sites with Lewis acidity or directly provides surface acidic sites, thereby efficiently catalyzing the dehydration condensation reaction of trimethylsilanol. The trimethylsilanol is then hydrolyzed (second reaction) to generate the byproduct hexamethyldisiloxane, which is recycled and used as a raw material to react with sulfur trioxide to prepare bis(trimethylsilyl)sulfate. This achieves material recycling, significantly saves economic costs, greatly improves atom utilization, atom economy, and the greenness of the process, solves the problem of high-salt wastewater generation in traditional oxidation routes, and converts all major byproducts into valuable products, conforming to green chemistry principles and demonstrating feasibility for industrial production.

[0013] In this invention, under the action of a catalyst, the main reaction for the production of vinyl sulfate and the side reaction for the generation of the byproduct hexamethyldisiloxane occur. The specific reaction process is as follows (taking aluminum trichloride as a catalyst as an example).

[0014] Main reaction: .

[0015] Side reactions: .

[0016] Furthermore, hexamethyldisiloxane can react with sulfur trioxide to generate bis(trimethylsilyl)sulfate, the raw material for the main product, as shown in the following reaction formula.

[0017] .

[0018] As a preferred embodiment of the present invention, with the molar amount of the alkyl diol being 100%, the molar amount of the metal halide catalyst is 5% to 10%, for example, 5%, 6%, 7%, 8%, 9% or 10%.

[0019] In this invention, the molar amount of metal halide directly affects the progress and reaction temperature of the first reaction, and also has a significant impact on the subsequent second reaction of trimethylsilanol. With the molar amount of the alkyl diol as 100%, the molar amount of the metal halide catalyst added is 5% to 10%, which is an excess addition. Furthermore, it can continue to provide active sites with Lewis acidity after the catalyst is recovered.

[0020] As a preferred embodiment of the present invention, the metal halide includes any one or a combination of at least two of aluminum trichloride, ferric chloride, zinc chloride or tin chloride; more preferably aluminum chloride.

[0021] In the technical solution of the present invention, aluminum chloride is used as a catalyst, which can play a better role and is more conducive to the excellent catalytic performance of the dehydration condensation reaction of trimethylsilanol while obtaining vinyl sulfate, thereby further improving the yield of vinyl sulfate and hexamethyldisiloxane.

[0022] As a preferred embodiment of the present invention, the molar ratio of the bis(trimethylsilyl)sulfate to the alkyl diol is 1:(1~1.2), for example, 1:1, 1:1.03, 1:1.05, 1:1.08, 1:1.1, 1:1.13, 1:1.15, 1:1.18 or 1:1.2, etc.

[0023] It is understood that the alkyl diol in this invention can be used in appropriate excess to make the reaction more complete and avoid incomplete reaction.

[0024] Furthermore, the present invention does not limit the specific types of alkyl diols. Those skilled in the art can make adaptive selections and adjustments according to actual needs. For example, the alkyl diol can be ethylene glycol, etc.

[0025] As a preferred embodiment of the present invention, the first solvent includes dichloromethane.

[0026] This invention uses dichloromethane as the first solvent for the preparation of vinyl sulfate. On the one hand, its low boiling point reduces the reaction temperature to a certain extent, thereby improving the product yield and purity. On the other hand, it can also alleviate the exothermic situation in the first reaction process, ensuring that the reaction proceeds smoothly and in a controllable manner.

[0027] As a preferred technical solution of the present invention, the mixing method includes:

[0028] The alkyl diol, metal halide catalyst, and first solvent are first mixed to form the reaction solution; the bis(trimethylsilyl) sulfate and the first solvent are second mixed to obtain the dropwise solution.

[0029] The solution is added dropwise to the solution to be reacted, and then the first reaction is carried out.

[0030] It is understood that the present invention does not limit the specific time of dripping; it can be adapted and adjusted according to the amount of raw materials and the size of the instrument. Furthermore, the ambient temperature for dripping can be low, such as -20℃ to 10℃, and can be -20℃, -18℃, -15℃, -13℃, -10℃, -8℃, -5℃, -3℃, 0℃, 1℃, 3℃, 5℃, 8℃, or 10℃, etc.

[0031] Optionally, the dripping time is 1h to 6h, for example, 1h, 2h, 3h, 4h, 5h or 6h.

[0032] As a preferred technical solution of the present invention, the reaction temperature of the first reaction is -10℃ to 10℃, for example -10℃, -8℃, -5℃, -3℃, 0℃, 1℃, 3℃, 5℃, 8℃ or 10℃, etc.

[0033] In the first reaction process, the present invention can be carried out without excessively high reaction temperature, which reduces the difficulty of industrial preparation and simplifies the preparation cost. Furthermore, by adjusting the temperature to -10℃ to 10℃, catalyst residues, trimethylsilanol and vinyl sulfate can be better separated.

[0034] As a preferred embodiment of the present invention, the reaction time of the first reaction is 4h to 12h, for example, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h.

[0035] As a preferred technical solution of the present invention, after the first reaction is completed, the solution after the reaction is subjected to neutralization treatment, phase separation treatment, washing treatment and solid-liquid separation treatment to obtain catalyst residue and solution to be treated.

[0036] In order to prevent the decomposition of the generated vinyl sulfate product after the first reaction, the reaction solution after the first reaction can be neutralized. Specifically, this includes adding saturated sodium bicarbonate for quenching, keeping the solution temperature below 10°C until no bubbles are generated, and testing the pH paper to show that the reaction solution is neutral.

[0037] In response, the solution after the reaction is subjected to phase separation treatment to separate the aqueous phase and the organic phase. The organic phase includes the first solvent, water-soluble impurities, alkyl diols, catalyst residues, trimethylsilanol and vinyl sulfate.

[0038] The organic phase is then washed with water and saturated sodium chloride in sequence, which removes other substances in the organic phase except for trimethylsilyl alcohol and vinyl sulfate. Furthermore, under the action of saturated sodium chloride, the salting-out effect further makes the interface between the two phases clearer and reduces emulsification.

[0039] After washing, the present invention can perform dehydration treatment, for example by adding anhydrous magnesium sulfate, and then perform centrifugation to separate solid and liquid phases, to obtain solid catalyst residue and liquid solution to be treated, wherein the solution to be treated contains trimethylsilanol and vinyl sulfate.

[0040] Optionally, the number of water washes is 1 to 3 times, for example, 1 time, 2 times or 3 times.

[0041] Optionally, the water removal treatment time is 0.5h to 1h, for example, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1h.

[0042] Optionally, the centrifugation speed after the first reaction is 3000 r / min to 6000 r / min, for example, 3000 r / min, 4000 r / min, 5000 r / min or 6000 r / min.

[0043] As a preferred technical solution of the present invention, the solution to be treated is evaporated and concentrated, and then a second solvent is added to obtain a second solvent system solution. The second solvent system solution is subjected to a first vacuum distillation to obtain a fore-distillate component containing trimethylsilanol and a solution containing vinyl sulfate.

[0044] Optionally, the second solvent includes toluene. The present invention selects toluene as the solvent for the subsequent solution to be treated, which is beneficial for the separation and recovery of vinyl sulfate.

[0045] The present invention can recover a foredistillation fraction containing trimethylsilanol and a solution containing vinyl sulfate by performing a first vacuum distillation process. The foredistillation fraction containing trimethylsilanol will inevitably contain a small amount of vinyl sulfate.

[0046] As a preferred technical solution of the present invention, the vacuum gauge pressure of the first vacuum distillation is -0.08MPa to -0.1MPa, for example -0.08MPa, -0.09MPa or -0.1MPa.

[0047] As a preferred technical solution of the present invention, the temperature of the first vacuum distillation is 40℃~60℃, for example 40℃, 45℃, 50℃, 55℃ or 60℃.

[0048] As a preferred technical solution of the present invention, the foredistillation component containing trimethylsilanol is subjected to a second reaction with the catalyst residue to recover hexamethyldisiloxane, which is used as a raw material for the preparation of bis(trimethylsilyl)sulfate.

[0049] As a preferred embodiment of the present invention, the reaction temperature of the second reaction is 80℃~100℃, for example, 80℃, 85℃, 90℃, 95℃ or 100℃.

[0050] As a preferred embodiment of the present invention, the reaction time of the second reaction is 1h to 6h, for example, 1h, 2h, 3h, 4h, 5h or 6h.

[0051] This invention regulates the reaction temperature and time of the second reaction. Under the action of the reaction temperature of 80℃~100℃ in the second reaction, the catalyst residue in the second solvent system can be better converted into active sites with Lewis acidity, or directly provide more surface acidic sites, which further efficiently catalyzes the dehydration condensation reaction of trimethylsilanol to obtain hexamethyldisiloxane and improves the recovery rate.

[0052] As a preferred technical solution of the present invention, the reaction solution after the second reaction is subjected to a second vacuum distillation treatment to obtain a supernatant and hexamethyldisiloxane; the supernatant is subjected to solid-liquid separation to obtain impurities containing the catalyst and a reaction solution that has been preliminarily purified.

[0053] Understandably, since the foredistillation component containing trimethylsilanol inevitably contains a small amount of vinyl sulfate, the byproduct hexamethyldisiloxane can be recovered after the second vacuum distillation. After drying, the byproduct can react with sulfur trioxide to prepare the raw material bis(trimethylsilyl)sulfate, thereby maximizing resource utilization. The remaining solution can be reused after solid-liquid separation by centrifugation to obtain a preliminary impurity-removed reaction solution containing a small amount of vinyl sulfate. Insoluble matter containing catalyst ions and other impurities is removed by centrifugation, which can greatly increase the purity of the final product.

[0054] As a preferred technical solution of the present invention, the solution containing vinyl sulfate and the reaction solution after preliminary impurity removal are subjected to a third vacuum distillation, filtration, recrystallization and drying to obtain the vinyl sulfate.

[0055] The present invention removes the second solvent by a third vacuum distillation, and then obtains high-purity ethylene sulfate by filtration and recrystallization. After drying, high-yield and high-purity ethylene sulfate is obtained.

[0056] As a preferred technical solution of the present invention, the temperature of the filtration recrystallization is -30℃ to 0℃, for example -30℃, -25℃, -20℃, -15℃, -10℃, -5℃ or 0℃.

[0057] As a preferred technical solution of the present invention, the drying temperature of the drying process is 50℃~80℃, for example 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃.

[0058] In a second aspect, the present invention also provides a vinyl sulfate ester, which is prepared by the comprehensive preparation method described in the first aspect.

[0059] As a preferred embodiment of the present invention, the yield of the ethylene sulfate is ≥80% and the purity is ≥99.5%.

[0060] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] The comprehensive preparation method provided by this invention uses inexpensive and readily available metal halides as catalysts in an organic system, lowering the reaction temperature. Bis(trimethylsilyl)sulfate and alkyl diol undergo an ester exchange cyclization reaction at low temperature (first reaction) to obtain the ethylene sulfate. Simultaneously, the catalyst can be used for two purposes, completing the two-step catalysis without the need for additional catalysts. Furthermore, under the action of the catalyst residue, trimethylsilanol is hydrolyzed (second reaction) to generate the byproduct hexamethyldisiloxane, which is recycled and used as a raw material to react with sulfuric acid to prepare bis(trimethylsilyl)sulfate. This achieves material recycling, significantly saves economic costs, greatly improves atom utilization, atom economy, and the greenness of the process, solves the problem of high-salt wastewater generation in traditional oxidation routes, and converts all major byproducts into valuable products, conforming to green chemistry principles and demonstrating feasibility in industrial production. Detailed Implementation

[0063] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0064] The "range" disclosed in this invention can be defined in the form of 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 the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning 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 specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, 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" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0065] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0066] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0067] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0068] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), meaning that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0069] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0070] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0071] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0072] In this invention, "optional" means that something is optional, that is, it refers to either "with" or "without". If there are multiple "optional" options in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "optional" option is independent.

[0073] In this invention, "room temperature" generally refers to 4℃~35℃, and can refer to 20℃±5℃. In some embodiments of this invention, room temperature refers to 20℃~30℃.

[0074] Example 1

[0075] This embodiment provides a comprehensive method for preparing vinyl sulfate, the method comprising the following steps:

[0076] (1) Add 1.1 mol of ethylene glycol and anhydrous aluminum trichloride (the molar amount of AlCl3 added is 8% of the total molar amount of ethylene glycol, 5.5 g) to a three-necked flask, then add 300 g of dichloromethane, start stirring, put the three-necked flask into a freezing bath, and cool it to -10℃ to obtain the reaction solution.

[0077] (2) Dissolve 1 mol of bis(trimethylsilyl) sulfate in 100 g of dichloromethane (the first solvent), transfer it into a constant pressure dropping funnel to obtain a dropping solution, and add the dropping solution to the reaction solution in a three-necked flask for 3 h.

[0078] (3) After the addition is complete, the temperature is raised to 0℃ for the first reaction for 8 hours to obtain a reaction solution containing catalyst residue, trimethylsilyl alcohol and vinyl sulfate.

[0079] (4) After the reaction is completed, a pre-cooled saturated sodium bicarbonate solution is slowly added to the reaction solution in step (3) to quench the reaction. The solution temperature is always kept below 10°C until no bubbles are generated. The pH test paper shows that the reaction solution is neutral.

[0080] (5) Transfer the reaction mixture from step (4) into a separatory funnel to separate the aqueous phase and the dichloromethane organic phase. The dichloromethane organic phase is washed with water (twice) and saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and then separated into solid and liquid phases by centrifugation to obtain the solid catalyst residue and the liquid solution to be treated. The solution to be treated contains trimethylsilanol and vinyl sulfate.

[0081] (6) The supernatant (solution to be treated) after centrifugation is first evaporated at 50°C to remove low-boiling-point solvents such as dichloromethane. When the solution is concentrated to a minimum, 300g of toluene (second solvent) is added to the bottle and the residual dichloromethane is replaced by rotary evaporation again to finally obtain the toluene system solution.

[0082] (7) The toluene solution containing vinyl sulfate in step (6) is subjected to a first vacuum distillation at a temperature of 50°C and a gauge pressure of -0.1 MPa. The first fraction (containing trimethylsilanol, hexamethyldisiloxane and a small amount of toluene) is collected, and the remaining solution is a toluene solution containing vinyl sulfate.

[0083] (8) Add the pre-distillate collected in step (7) to the solid product catalyst residue after centrifugation in step (5), use the catalyst residue as a catalyst for dehydration reaction, add 300g of toluene, install a water separator, heat at 85°C, condense and separate water, reflux the toluene, and carry out dehydration reaction for 3 hours (second reaction) to obtain toluene system solution.

[0084] (9) After the second reaction in step (8) is completed until no water is generated, the temperature is 45℃ and the gauge pressure of the vacuum degree is -0.1Mpa. The hexamethyldisiloxane fraction is recovered by second vacuum distillation. After drying, it is reacted with sulfur trioxide to prepare the raw material bis(trimethylsilyl)sulfate.

[0085] (10) In step (9), the remaining solution is a toluene solution containing aluminum salt and a small amount of vinyl sulfate. The remaining solution is separated by centrifugation to obtain the supernatant, which is a toluene solution containing a small amount of vinyl sulfate.

[0086] (11) The remaining toluene solution (containing vinyl sulfate) from step (7) was combined with the toluene solution containing a small amount of vinyl sulfate from step (10), and most of the toluene was distilled off under reduced pressure. After concentration, the solution was cooled to -20°C and allowed to stand. After crystallization and filtration, the solution was dried under reduced pressure at 70°C for 6 hours to finally obtain the vinyl sulfate. Example 2

[0087] This embodiment provides a comprehensive method for preparing vinyl sulfate, the method comprising the following steps:

[0088] (1) Add 1.2 mol of ethylene glycol and anhydrous aluminum trichloride (the molar amount of AlCl3 added is 8% of the molar amount of ethylene glycol, 6 g) to a three-necked flask, then add 300 g of dichloromethane, start stirring, put the three-necked flask into a freezing bath, and cool it to -10℃ to obtain the reaction solution.

[0089] (2) Dissolve 1 mol of bis(trimethylsilyl)sulfate in 100 g of dichloromethane (the first solvent), transfer it into a constant pressure dropping funnel to obtain a dropping solution, and add the dropping solution to the reaction solution in a three-necked flask for 6 h.

[0090] (3) After the addition is complete, the temperature is raised to 10°C for the first reaction for 12 hours to obtain a reaction solution containing catalyst residue, trimethylsilyl alcohol and vinyl sulfate.

[0091] (4) After the reaction is completed, a pre-cooled saturated sodium bicarbonate solution is slowly added to the reaction solution in step (3) to quench the reaction. The solution temperature is always maintained at 0°C until no bubbles are generated. The pH test paper shows that the reaction solution is neutral.

[0092] (5) Transfer the reaction mixture from step (4) into a separatory funnel to separate the aqueous phase and the dichloromethane organic phase. The dichloromethane organic phase is washed with water (3 times) and saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and then separated into solid and liquid phases by centrifugation to obtain the solid catalyst residue and the liquid solution to be treated. The solution to be treated contains trimethylsilanol and vinyl sulfate.

[0093] (6) The supernatant (solution to be treated) after centrifugation is first evaporated at 60°C to remove low-boiling-point solvents such as dichloromethane. When the solution is concentrated to a minimum, 300g of toluene (second solvent) is added to the bottle and the residual dichloromethane is replaced by rotary evaporation again to finally obtain the toluene system solution.

[0094] (7) The toluene solution containing vinyl sulfate in step (6) is subjected to a first vacuum distillation at a temperature of 60°C and a vacuum gauge pressure of -0.8 MPa. The first fraction (containing trimethylsilanol, hexamethyldisiloxane and a small amount of toluene) is collected, and the remaining solution is a toluene solution containing vinyl sulfate.

[0095] (8) Add the pre-distillate collected in step (7) to the solid product catalyst residue after centrifugation in step (5), use the catalyst residue as a catalyst for dehydration reaction, add 300g of toluene, install a water separator, heat at 100℃, condense and separate water, reflux the toluene, and carry out dehydration reaction for 1 hour (second reaction) to obtain toluene system solution.

[0096] (9) After the second reaction in step (8) is completed until no water is generated, the temperature is 60℃ and the gauge pressure of the vacuum degree is -0.08Mpa. The hexamethyldisiloxane fraction is recovered by second vacuum distillation. After drying, it is reacted with sulfur trioxide to prepare the raw material bis(trimethylsilyl)sulfate.

[0097] (10) In step (9), the remaining solution is a toluene solution containing aluminum salt and a small amount of vinyl sulfate. The remaining solution is separated by centrifugation to obtain the supernatant, which is a toluene solution containing a small amount of vinyl sulfate.

[0098] (11) The remaining toluene solution (containing vinyl sulfate) in step (7) is combined with the toluene solution containing a small amount of vinyl sulfate in step (10), most of the toluene is distilled off under reduced pressure, concentrated and cooled to -10°C and allowed to stand. After crystallization and filtration, it is dried under reduced pressure at 50°C for 6 hours to finally obtain the vinyl sulfate.

[0099] Example 3

[0100] The difference between this embodiment and embodiment 1 is that in step (1) of this embodiment, the molar amount of AlCl3 added is 5% of the molar amount of ethylene glycol.

[0101] All other conditions remain the same as in Example 1.

[0102] Example 4

[0103] The difference between this embodiment and embodiment 1 is that in step (1) of this embodiment, the molar amount of AlCl3 added is 10% of the molar amount of ethylene glycol.

[0104] All other conditions remain the same as in Example 1.

[0105] Example 5

[0106] The difference between this embodiment and embodiment 1 is that the reaction temperature of the first reaction in step (3) of this embodiment is -10℃.

[0107] All other conditions remain the same as in Example 1.

[0108] Example 6

[0109] The difference between this embodiment and embodiment 1 is that the reaction temperature of the first reaction in step (3) of this embodiment is 20°C.

[0110] All other conditions remain the same as in Example 1.

[0111] Example 7

[0112] The difference between this embodiment and embodiment 1 is that the catalyst in step (1) of this embodiment is anhydrous tin chloride.

[0113] All other conditions remain the same as in Example 1.

[0114] Example 8

[0115] The difference between this embodiment and embodiment 1 is that in step (1) of this embodiment, the molar amount of AlCl3 added is 1% of the molar amount of ethylene glycol.

[0116] All other conditions remain the same as in Example 1.

[0117] Example 9

[0118] The difference between this embodiment and embodiment 1 is that this embodiment does not perform step (4), and directly performs step (5) on the reaction solution after the first reaction in step (3).

[0119] All other conditions remain the same as in Example 1.

[0120] Example 10

[0121] The difference between this embodiment and Embodiment 1 is that the first solvent in this embodiment is toluene, that is, dichloromethane is replaced with toluene.

[0122] All other conditions remain the same as in Example 1.

[0123] Comparative Example 1

[0124] The difference between this comparative example and Example 1 is that aluminum trichloride catalyst is not added to this comparative example.

[0125] All other conditions remain the same as in Example 1.

[0126] Comparative Example 2

[0127] The difference between this comparative example and Example 1 is that in step (8) of this comparative example, no catalyst residue is added and the recycling process is carried out directly.

[0128] All other conditions remain the same as in Example 1.

[0129] The purity and yield of hexamethyldisiloxane and vinyl sulfate obtained by the preparation methods provided in Examples 1-10 and Comparative Examples 1-2 were tested and calculated. The yield was calculated as follows:

[0130] Based on the specific chemical reaction equation.

[0131] Theoretical yield of vinyl sulfate = dosage of bis(trimethylsilyl) sulfate × 124.12 / 242.44.

[0132] Actual yield = Actual yield / Theoretical yield of vinyl sulfate.

[0133] Theoretical yield of hexamethyldisiloxane = Actual yield of trimethylsilanol × 162.38 / 2 / 90.2.

[0134] Actual yield of hexamethyldisiloxane = Actual yield / Theoretical yield of hexamethyldisiloxane.

[0135] The purity of vinyl sulfate was determined by gas chromatography (GC), and the test results are shown in Table 1.

[0136] Table 1

[0137]

[0138] From Table 1, we can obtain:

[0139] The comprehensive preparation method provided by this invention allows the catalyst to be used in two ways while preparing vinyl sulfate, generating a byproduct hexamethyldisiloxane, which can be recycled and used as a raw material to react with sulfuric acid to prepare bis(trimethylsilyl)sulfate. This achieves material recycling, significantly saves economic costs, greatly improves atom economy and the greenness of the process, and has certain feasibility in industrial production.

[0140] Data analysis of Examples 1, 5, and 6 shows that the first reaction process can be carried out without excessively high reaction temperatures, reducing the difficulty of industrial preparation and simplifying the preparation cost. Furthermore, adjusting the temperature to -10℃ to 10℃ allows for better separation of catalyst residues, trimethylsilanol, and vinyl sulfate, further improving the yield of hexamethyldisiloxane and vinyl sulfate, as well as increasing the purity of vinyl sulfate.

[0141] Data analysis of Examples 1 and 7 shows that using aluminum chloride as a catalyst eliminates the need for excessively high reaction temperatures in the first reaction process and effectively utilizes the catalytic effect of catalyst residues in the second reaction process of trimethylsilanol. This not only improves the yield of ethylene sulfate but also significantly increases the yield of hexamethyldisiloxane.

[0142] Data analysis of Examples 1, 3, 4, and 8 shows that, based on the molar amount of the alkyl diol being 100%, the molar amount of the metal halide catalyst added is 5% to 10%, which is an excess addition. This allows the catalyst to continue providing active sites with Lewis acidity after subsequent catalyst recovery, thereby better improving the yield of hexamethyldisiloxane and vinyl sulfate, and also improving the purity of vinyl sulfate.

[0143] Data analysis of Examples 1 and 9 shows that neutralization after the first reaction effectively prevents the decomposition of the generated vinyl sulfate product, thus avoiding its impact on subsequent yield and purity.

[0144] Data analysis of Examples 1 and 10 shows that using dichloromethane as the solvent for the first reaction lowers the reaction temperature and also helps to initially separate the products after the second reaction.

[0145] Analysis of the data from Example 1, Comparative Example 1, and Comparative Example 2 shows that, without a catalyst, bis(trimethylsilyl)sulfate and ethylene glycol can hardly react effectively at low temperatures; at the same time, without catalyst recovery, the yield of the byproduct hexamethyldisiloxane will be greatly reduced.

[0146] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A comprehensive method for preparing vinyl sulfate, characterized in that, The preparation method includes the following steps: A first reaction was carried out by mixing bis(trimethylsilyl)sulfate, alkyl diol, metal halide catalyst and first solvent to obtain catalyst residue, trimethylsilanol and vinyl sulfate. The catalyst residue was reacted with trimethylsilanol in a second reaction to recover hexamethyldisiloxane, which was then used as a raw material for the preparation of bis(trimethylsilyl)sulfate.

2. The comprehensive preparation method of vinyl sulfate according to claim 1, characterized in that, Based on the molar amount of the alkyl diol being 100%, the molar amount of the metal halide catalyst added is 5% to 10%; And / or, the metal halide includes any one or a combination of at least two of aluminum trichloride, ferric chloride, zinc chloride, or tin chloride; And / or, the molar ratio of the bis(trimethylsilyl)sulfate to the alkyl diol is 1:(1~1.2). And / or, the first solvent includes dichloromethane.

3. The comprehensive preparation method of vinyl sulfate according to claim 1 or 2, characterized in that, The mixing methods include: The alkyl diol, metal halide catalyst, and first solvent are first mixed to form the reaction solution; the bis(trimethylsilyl) sulfate and the first solvent are second mixed to obtain the dropwise solution. The solution is added dropwise to the solution to be reacted, and then the first reaction is carried out. And / or, the reaction temperature of the first reaction is -10℃ to 10℃; And / or, the reaction time of the first reaction is 4h to 12h.

4. The comprehensive preparation method of vinyl sulfate according to claim 1, characterized in that, After the first reaction is completed, the solution after the reaction is subjected to neutralization, phase separation, washing and solid-liquid separation to obtain catalyst residue and solution to be treated.

5. The comprehensive preparation method of vinyl sulfate according to claim 4, characterized in that, The solution to be treated is evaporated and concentrated, and then a second solvent is added to obtain a second solvent system solution. The second solvent system solution is subjected to a first vacuum distillation to obtain a fore-distillate containing trimethylsilanol and a solution containing vinyl sulfate.

6. The comprehensive preparation method of vinyl sulfate according to claim 5, characterized in that, The vacuum gauge pressure of the first vacuum distillation is -0.08MPa to -0.1MPa, and the temperature of the first vacuum distillation is 40℃ to 60℃. And / or, the foredistillate component containing trimethylsilanol is subjected to a second reaction with the catalyst residue to recover hexamethyldisiloxane, which is used as a raw material for the preparation of bis(trimethylsilyl)sulfate.

7. The comprehensive preparation method of vinyl sulfate according to claim 6, characterized in that, The reaction temperature of the second reaction is 80℃~100℃, and the reaction time of the second reaction is 1h~6h; And / or, the reaction solution after the second reaction is subjected to a second vacuum distillation to obtain a supernatant and hexamethyldisiloxane; the supernatant is subjected to solid-liquid separation to obtain impurities containing the catalyst and a reaction solution that has been preliminarily purified.

8. The comprehensive preparation method of vinyl sulfate according to claim 7, characterized in that, The solution containing vinyl sulfate and the reaction solution after preliminary purification were subjected to a third vacuum distillation, filtration, recrystallization, and drying to obtain the vinyl sulfate. The temperature for filtration and recrystallization is -30℃ to 0℃, and the drying temperature for the drying process is 50℃ to 80℃.

9. A vinyl sulfate, characterized in that, The vinyl sulfate is prepared by the comprehensive preparation method of vinyl sulfate as described in any one of claims 1-8.

10. The vinyl sulfate according to claim 9, characterized in that, The yield of the ethylene sulfate is ≥80%, and the purity is ≥99.5%.

Images