A process for the preparation of ethylene sulfate

Abstract

This invention provides a method for preparing vinyl sulfate. Using ethylene glycol as a raw material, ethylene sulfite is synthesized via thionylation reaction. Part of the solvent is removed by distillation to obtain crude ethylene sulfite. A cheap catalyst is used for oxidation with hydrogen peroxide and sodium chlorite solution, followed by recrystallization to obtain vinyl sulfate, a lithium-ion battery additive. This one-pot method reduces the reaction process, and the use of hydrogen peroxide and sodium chlorite solution as the oxidant significantly reduces wastewater volume. Furthermore, adjusting the ratio of hydrogen peroxide to sodium chlorite lowers the cost of the oxidant. This invention is environmentally friendly, yields ideal results, has high purity, uses readily available and inexpensive raw materials, and has low production costs, making it suitable for industrial applications.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical synthesis, and specifically relates to a method for preparing vinyl sulfate. Background Technology

[0002] Ethylene sulfate (DTD) is a novel and high-performance electrolyte additive for lithium-ion batteries. When added to lithium-ion battery electrolytes, it effectively inhibits the initial capacity decline of lithium-ion batteries, increases the initial discharge capacity, improves the charge-discharge performance of the battery, extends battery cycle life, and exhibits compatibility at both high and low temperatures, making it an excellent lithium-ion battery electrolyte additive.

[0003] The current market demand for vinyl sulfate is relatively stable, while production capacity is increasing year by year. With the rapid development of the electric vehicle industry and the continuous expansion of production capacity and downstream application areas, the market demand for vinyl sulfate is constantly rising. The development of efficient industrial synthesis technology for vinyl sulfate will help promote the sustainable development of downstream enterprises and will have good economic and social benefits.

[0004] Numerous methods for synthesizing vinyl sulfate have been reported in current literature and patents:

[0005] 1. Substitution Method: In 1932, Baker W and Field F B reported a method for synthesizing vinyl sulfate via nucleophilic substitution reaction using Ag₂SO₄ and dibromoethane as reactants in Cyclic esters of Sulphuric Acid[J]. Although this method is simple to operate, the product yield is low, and the use of Ag salts as reactants leads to a significant increase in cost.

[0006]

[0007] 2. Addition Method: Patent CN101210007B uses ethylene oxide and sulfur dioxide (or sulfur trioxide) as raw materials to produce cyclic vinyl sulfate via a catalytic addition reaction. This method uses highly hazardous ethylene oxide and highly corrosive sulfur dioxide (or sulfur trioxide) to the reaction equipment, and also causes environmental pollution. Therefore, considering both production costs and environmental impact, this method is difficult to promote.

[0008]

[0009] 3. Acylation method: Patent CN109776487A uses ethylene glycol as a raw material, which reacts directly with thioyl chloride to produce vinyl sulfate. The raw material is cheap, but the product yield is low, and thioyl chloride is highly corrosive to equipment and causes significant environmental pollution, making it unsuitable for industrial application.

[0010]

[0011] 4. Dioxane Synthesis Method: Patent CN107353277A describes a method for producing vinyl sulfate using 1,4-dioxane and sulfur trioxide as raw materials. This method uses inexpensive and readily available raw materials, but it cannot achieve very high yields of vinyl sulfate, and the purification process presents certain difficulties.

[0012]

[0013] 5. Oxidation Method: Several routes for this method have been disclosed, primarily including the following oxidation reaction routes: Patent CN1025498C uses sodium hypochlorite as an oxidant to obtain vinyl sulfate under ruthenium trichloride catalysis. Patent CN109516971A uses an organic oxidant to oxidize and obtain vinyl sulfate. Patent CN109988145B uses air oxidation to obtain vinyl sulfate. Patent CN101456857A uses potassium permanganate as an oxidant to oxidize and obtain vinyl sulfate. Patent CN106187989A uses sodium percarbonate as an oxidant to synthesize vinyl sulfate.

[0014] Currently, the main method used in laboratories and industry is to synthesize sodium hypochlorite using ruthenium trichloride as an oxidant. This method has several drawbacks, including the easy decomposition and expiration of the sodium hypochlorite solution, the presence of large amounts of sodium chloride salts in the solution, the low sodium hypochlorite content leading to huge wastewater volumes, and the high cost of ruthenium trichloride catalyst. The synthesis equation for this method is shown below.

[0015]

[0016] While methods for synthesizing vinyl sulfate have been continuously improving, several problems remain: gas synthesis requires sophisticated equipment and involves significant upfront investment; most routes utilize transition metal catalysts, increasing reaction costs and complexity; and traditional methods often require excessive oxidants, generating large amounts of waste liquid with significant environmental impact. Therefore, this invention aims to address the shortcomings of existing technologies by providing a method for preparing vinyl sulfate that utilizes readily available raw materials, uses economical catalysts, has a short reaction time, is easy to operate, produces fewer byproducts, generates high-purity products, and generates less wastewater. Summary of the Invention

[0017] This invention provides an improved method for preparing vinyl sulfate, which can reduce environmental pollution, reduce wastewater volume, and is more environmentally friendly. It also has the advantages of simple operation, safety, and ideal yield.

[0018] To achieve the above objectives, the present invention provides the following technical solution:

[0019] A method for preparing vinyl sulfate, the method comprising the following steps:

[0020] (1) Acylation reaction: Add haloalkanes solvent and ethylene glycol to reaction vessel A (equipped with a dropping vessel), control the system temperature at 10-40℃, add thionyl chloride dropwise, and react for 0.5-2 hours; after the reaction is complete, distill under reduced pressure to remove hydrogen chloride and part of the solvent, and obtain a haloalkane solution containing ethylene sulfite. Put the haloalkane solution containing ethylene sulfite into reaction vessel B (equipped with a dropping vessel, a layering sight glass, etc.) for later use; the reaction equation is shown below:

[0021]

[0022] (2) Oxidation reaction: A certain amount of haloalkane solvent was added to reaction vessel B, the pH was adjusted with buffer solution, a catalyst was added, the solution temperature was controlled at 0-40℃, hydrogen peroxide solution was added dropwise, followed by sodium chlorite solution. After the addition was completed, the reaction continued for 1-60 min. After the reaction was completed, the mixture was separated, extracted, washed, and dried to obtain a haloalkane solution containing vinyl sulfate. The solution was washed and dried, concentrated under low temperature and reduced pressure until the solution was saturated, a certain amount of unsuitable solvent was added dropwise, the mixture was cooled to crystallize, and filtered to obtain crude vinyl sulfate. The reaction equation is shown below:

[0023]

[0024] (3) Refining and drying of vinyl sulfate: Crude vinyl sulfate is added to a certain proportion of dimethyl carbonate solvent by weight, stirred and heated to a certain temperature to dissolve it, filtered through a titanium rod filter to obtain filtrate, stirred and cooled to crystallize to a certain temperature, centrifuged with a closed fully automatic centrifuge to obtain solid vinyl sulfate, and dried with a fully automatic belt dryer to obtain electronic grade standard finished product.

[0025] Furthermore, in step (1), the molar ratio of thionyl chloride to ethylene glycol is 0.9-1.5:1.

[0026] Furthermore, in step (1), thionyl chloride is added dropwise, and the acylation reaction is carried out at 10–80 °C.

[0027] Furthermore, in step (1), thionyl chloride is added dropwise, and the acylation reaction is carried out at 10–40 °C.

[0028] Furthermore, after the reaction in step (1) is completed, the vacuum level is controlled to be 10 mmHg-500 mmHg, and the solvent is recovered.

[0029] Furthermore, in step (2), one or a combination of two of sodium carbonate, sodium bicarbonate, sodium dihydrogen phosphate, and sodium hydroxide are used as the reaction buffer solution.

[0030] Furthermore, in step (2), one of iron oxide, ferric sulfate, and titanium silicate molecular sieve is used as the catalyst for the oxidation reaction.

[0031] Furthermore, the molar ratio of ethylene glycol to hydrogen peroxide in the hydrogen peroxide solution is 1:0.5 to 1.5.

[0032] Furthermore, the molar ratio of ethylene glycol to sodium chlorite is 1:0.2 to 1.5.

[0033] Furthermore, the molar ratio of ethylene glycol to oxidant is 1:0.2 to 0.8.

[0034] Furthermore, sodium carbonate or sodium hydroxide is added to the sodium chlorite aqueous solution to improve the stability of the solution.

[0035] Furthermore, the amount of sodium carbonate or sodium hydroxide added to the sodium chlorite aqueous solution is 0.1-1% of the total solution.

[0036] Furthermore, the oxidation reaction is carried out at 0–40°C.

[0037] Furthermore, the preparation method also includes a crystallization step, a recrystallization step, and a drying step.

[0038] Furthermore, the solvent used in the crystallization step is one or more combinations selected from dichloromethane, dichloroethane, n-heptane, and n-hexane.

[0039] Furthermore, the solvent used in the crystallization step is a combination of dichloroethane and n-heptane.

[0040] Furthermore, the solvent used in the recrystallization step is one or more combinations selected from dimethyl carbonate, diethyl carbonate, ethyl acetate, dichloromethane, and dichloroethane.

[0041] Furthermore, the solvent used in the recrystallization step is dimethyl carbonate.

[0042] Further, the method for preparing thionyl chloride is as follows: chlorine and sulfur are mixed in a molar ratio of 1:1.4 in a synthesizer at 55°C to obtain disulfur dichloride. The disulfur dichloride is then placed in a converter, and chlorine with the same molar amount as sulfur is added. The mixture is then synthesized at 70°C to obtain a mixed gas. The mixed gas is kept at 75°C and sent to a catalytic synthesizer containing activated carbon. Sulfur dioxide with 0.6 times the molar amount of sulfur is added simultaneously. The mixture is then catalytically synthesized at 250°C to obtain thionyl chloride. The reactants are cooled to obtain crude thionyl chloride. The crude thionyl chloride is then fed into a distillation vessel pre-filled with sulfur powder and distilled at 110°C to obtain thionyl chloride with a purity of 99%.

[0043] Further, the method for preparing sodium chlorite is as follows: 35 wt% hydrochloric acid aqueous solution is added to 33 wt% sodium chlorate aqueous solution, with a molar ratio of hydrochloric acid to sodium chlorate solution of 0.7:1. The mixed gas of chlorine dioxide and chlorine generated by the reaction is passed into an excess of 25 wt% sodium chlorite aqueous solution, with a molar ratio of chlorine to sodium chlorite of 1:2.7. Chlorine reacts with sodium chlorite to generate chlorine dioxide. Finally, chlorine dioxide gas is passed into 35 wt% sodium hydroxide aqueous solution, and 29 wt% hydrogen peroxide is added simultaneously to react and generate sodium chlorite, with a molar ratio of chlorine dioxide, sodium hydroxide and hydrogen peroxide of 1.9:1.9:1. Then, the mixture is crystallized and dried to generate solid sodium chlorite with a purity of 98%.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] 1. This invention overcomes the disadvantages of the process of preparing ethylene sulfate, which requires the production and use of sodium hypochlorite as an oxidant, which generates a large amount of brine wastewater and uses expensive rare metal catalysts. It is more environmentally friendly and environmentally friendly. At the same time, the preparation process is simple, the yield is ideal, the purity is high, the raw materials are cheap and readily available, the production cost is low, and it is suitable for industrial application.

[0046] 2. Compared with the oxidation process of sodium hypochlorite solution under ruthenium trichloride catalysis, the present invention can solve the problem that sodium hypochlorite oxidant is easily deteriorated during transportation, resulting in poor reaction effect; solve the problem of high synthesis cost caused by the use of expensive transition metal catalysts for catalytic oxidation; and solve the problem of large wastewater volume caused by high salt content and low sodium hypochlorite concentration in sodium hypochlorite solution.

[0047] 3. This invention uses ethylene glycol as a raw material to synthesize ethylene sulfite via thionylation reaction. After distillation to remove some of the solvent, crude ethylene sulfite intermediate is obtained. Using an inexpensive catalyst, ethylene sulfate is obtained by oxidation reaction with hydrogen peroxide and sodium chlorite solution, followed by recrystallization and purification to obtain ethylene sulfate, an additive for lithium-ion batteries. The one-pot method reduces the reaction process, and the use of hydrogen peroxide and sodium chlorite solution as oxidant can greatly reduce wastewater volume. Furthermore, by adjusting the ratio of hydrogen peroxide to sodium chlorite, the cost of the oxidant can be reduced.

[0048] 4. This invention uses sodium chlorite as an oxidant. Sodium chlorite is stable and can be prepared into an 80% solid solution, so long-distance transportation will not affect its quality. Sodium chlorite can be prepared as a 30% or higher concentration solution as an oxidant, reducing wastewater generation. The stability of the oxidant can be further improved by adding a small amount of alkali to the preparation of the sodium chlorite solution. Costs can be further reduced by adjusting the ratio of hydrogen peroxide to sodium chlorite. Using inexpensive iron oxide and ferric sulfate as catalysts can significantly reduce costs. Crystallization using mixed solvents can improve the yield and purity of the crude product. The residual solvent in the product can be dried using a fully automatic belt dryer to obtain a qualified finished product.

[0049] 5. During the preparation process, it was found that thionyl chloride and sodium chlorite are two important raw materials in the synthesis of vinyl sulfate, and their purity significantly affects the yield and purity of vinyl sulfate. Compared with other existing processes, the synthesis process of this invention, using commercially available products, improves both yield and purity. To further reduce the impact of raw materials on the process, this invention uses self-made thionyl chloride and sodium chlorite, further improving the product yield and purity. The preparation method of thionyl chloride and sodium chlorite in this invention is more environmentally friendly and resource-saving. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example 1

[0052] This embodiment provides a method for preparing vinyl sulfate, the method comprising the following steps:

[0053] (1) Acylation reaction: 200 kg of ethylene glycol and 300 kg of dichloroethane were pumped into reactor A, and stirring was started to cool the reactor to 20°C. 345 kg of thionyl chloride was added dropwise over 2 hours. After the addition was complete, the reaction continued for 1 hour. After the reaction was complete, vacuum distillation was performed to remove hydrogen chloride and unreacted thionyl chloride. The vacuum degree was controlled at 350-450 mmHg to obtain 457 kg of dichloroethane solution of ethylene sulfite, containing 266.5 kg of product, with a yield of 85.01%. The dichloroethane solution of ethylene sulfite was transferred to reactor B for later use.

[0054] (2) Oxidation reaction: 200 kg of dichloroethane was pumped into reactor B, followed by 50 kg of a buffer solution prepared with 10% sodium dihydrogen phosphate and sodium hydroxide (pH = 9). 3 kg of solid ferric sulfate was added, and the mixture was stirred and cooled until the reactor temperature dropped to 8°C. 182 kg of 30% hydrogen peroxide was added dropwise over 30 min. After the addition was complete, 291 kg of a 30% sodium chlorite aqueous solution (with 0.2% sodium hydroxide) was added dropwise over 1 h. After the sodium chlorite addition was complete, the reaction was maintained at the specified temperature. A sample was taken for GC analysis until the ethylene sulfite reaction was complete. The mixture was allowed to stand and separate into layers to obtain a dichloroethane solution of vinyl sulfate. The aqueous phase was extracted twice with dichloroethane, and the dichloroethane solutions were combined. The solution was washed once with 100 kg of 8% sodium bicarbonate solution, allowed to stand, and the aqueous layer was removed. The solution was then washed once with 20% sodium sulfate solution, allowed to stand, and the aqueous layer was removed. Add 50 kg of anhydrous magnesium sulfate powder to the oil layer, stir at room temperature (25°C) for 1 hour, and filter using a vacuum filter to obtain a solution of vinyl sulfate.

[0055] (3) The vinyl sulfate solution was pumped into a 1t distillation vessel and concentrated under reduced pressure at 50℃. 270kg of dichloroethane was distilled off and recovered. The solution was transferred to a crystallization vessel and 300kg of n-heptane was added dropwise while stirring. The mixture was then cooled and stirred to crystallize until the internal temperature of the crystallization vessel was 5-10℃. After centrifugation, 320kg of crude vinyl sulfate was obtained.

[0056] (4) 400 kg of dimethyl carbonate was pumped into the dissolving vessel and stirred. 320 kg of crude vinyl sulfate was added to the crystallization vessel and heated to 50°C to dissolve. The solution was filtered through a titanium rod filter into the crystallization vessel and cooled and stirred to crystallize. When the internal temperature reached 10°C, the crystallized liquid was centrifuged in a closed centrifuge to obtain vinyl sulfate filter cake. The cake was then transferred to a fully automatic belt dryer for vacuum drying to obtain 280 kg of finished product with a yield of 70.02%, a purity of 99.72%, a moisture content of 40 ppm, and an acid value of 35 ppm.

[0057] All raw materials used in this embodiment are commercially available.

[0058] Example 2

[0059] This embodiment provides a method for preparing vinyl sulfate, the method comprising the following steps:

[0060] (1) Acylation reaction: 200 kg of ethylene glycol and 350 kg of dichloroethane were pumped into reactor A, and stirring was started to cool the reactor to 40°C. 422 kg of thionyl chloride was added dropwise over 2 hours. After the addition was complete, the reaction continued for 1 hour. After the reaction was complete, vacuum distillation was performed to remove hydrogen chloride and unreacted thionyl chloride. The vacuum degree was controlled at 400-500 mmHg to obtain 550 kg of dichloroethane solution of ethylene sulfite, containing 317 kg of product, with a yield of 91%. The dichloroethane solution of ethylene sulfite was transferred to reactor B for later use.

[0061] (2) Oxidation reaction: 200 kg of dichloroethane was pumped into reactor B, along with 50 kg of a buffer solution prepared with 8% sodium bicarbonate (pH = 9), and 3 kg of solid ferric sulfate. The mixture was stirred and cooled until the reactor temperature dropped to 8°C. 220 kg of 30% hydrogen peroxide was added dropwise over 30 min. After the addition was complete, 194 kg of a 30% sodium chlorite aqueous solution (with 0.3% sodium carbonate) was added dropwise over 1 h. After the sodium chlorite solution was completely added, the reaction was maintained at the specified temperature. A sample was taken for GC analysis until the ethylene sulfite reaction was complete. The mixture was allowed to stand and separate into layers to obtain a dichloroethane solution of vinyl sulfate. The aqueous phase was extracted twice with dichloroethane, and the dichloroethane solutions were combined. The solution was washed once with 100 kg of 8% sodium bicarbonate solution, allowed to stand, and the aqueous layer was removed. The solution was then washed once with 20% sodium sulfate solution, allowed to stand, and the aqueous layer was removed. Add 50 kg of anhydrous magnesium sulfate powder to the oil layer, stir at room temperature (25°C) for 1 hour, and filter using a vacuum filter to obtain a solution of vinyl sulfate.

[0062] (3) The vinyl sulfate solution was pumped into a 1t distillation vessel and concentrated under reduced pressure at 50℃. 300kg of dichloroethane was distilled off and recovered. The solution was transferred to a crystallization vessel and 320kg of n-heptane was added dropwise under stirring to crystallize. The temperature was lowered and stirred to continue crystallization until the internal temperature reached 5-10℃. After centrifugation, 345kg of crude vinyl sulfate was obtained.

[0063] (4) 400 kg of dimethyl carbonate was pumped into the dissolving vessel and stirred. 345 kg of crude vinyl sulfate was added to the crystallization vessel and heated to 50°C to dissolve. The solution was filtered through a titanium rod filter into the crystallization vessel and cooled and stirred to crystallize. When the internal temperature reached 10°C, the crystallized liquid was centrifuged in a closed centrifuge to obtain vinyl sulfate filter cake. The cake was then transferred to a fully automatic belt dryer for vacuum drying to obtain 327 kg of finished product with a yield of 81.77%, a purity of 99.71%, a moisture content of 38 ppm, and an acid value of 24 ppm.

[0064] All raw materials used in this embodiment are commercially available.

[0065] Example 3

[0066] This embodiment provides a method for preparing vinyl sulfate, the method comprising the following steps:

[0067] (1) Cyclization reaction: 200 kg of ethylene glycol and 350 kg of dichloroethane were pumped into reactor A, and stirring was started to cool the reactor to 10 °C. 460 kg of thionyl chloride was added dropwise over 2 hours. After the addition was complete, the reaction continued for 1 hour. After the reaction was complete, vacuum distillation was performed to remove hydrogen chloride and unreacted thionyl chloride. The vacuum degree was controlled at 300-400 mmHg to obtain 485 kg of dichloroethane solution of ethylene sulfite, containing 331 kg of product, with a yield of 95.02%. The dichloroethane solution of ethylene sulfite was transferred to reactor B for later use.

[0068] (2) Oxidation reaction: 300 kg of dichloroethane was pumped into reactor B, followed by 60 kg of a buffer solution prepared with sodium dihydrogen phosphate and sodium hydroxide (pH = 9), and 3 kg of ferric oxide powder. The mixture was stirred and cooled until the reactor temperature dropped to 5°C. 292 kg of 30% hydrogen peroxide was added dropwise over 30 min. After the addition was complete, 242 kg of a 30% sodium chlorite aqueous solution (with 0.1% sodium hydroxide) was added dropwise over 1 h. After the sodium chlorite addition was complete, the reaction was maintained at the specified temperature. A sample was taken for GC analysis until the ethylene sulfite reaction was complete. The mixture was allowed to stand and separate into layers to obtain a dichloroethane solution of vinyl sulfate. The aqueous phase was extracted twice with dichloroethane, and the dichloroethane solutions were combined. The solution was washed once with 100 kg of 8% sodium bicarbonate solution, allowed to stand and separate into layers to remove the aqueous layer. The solution was then washed once with 20% sodium sulfate solution, allowed to stand and separate into layers, and the aqueous layer was removed. Add 50 kg of anhydrous magnesium sulfate powder to the oil layer, stir at room temperature (25°C) for 1 hour, and filter using a vacuum filter to obtain a solution of vinyl sulfate.

[0069] (3) The vinyl sulfate solution was pumped into a 1t distillation vessel and concentrated under reduced pressure at 50°C. 321kg of dichloroethane was distilled off and recovered. The solution was transferred to a crystallization vessel and 300kg of n-heptane was added dropwise under stirring for recrystallization. The temperature was lowered and stirred to continue crystallization until the internal temperature reached 5-10°C. After centrifugation, 356kg of vinyl sulfate was obtained.

[0070] (4) 400 kg of dimethyl carbonate was pumped into the dissolving vessel and stirred. 356 kg of crude vinyl sulfate was added to the crystallization vessel and heated to 50°C to dissolve. The solution was filtered through a titanium rod filter into the crystallization vessel and cooled and stirred to crystallize. When the internal temperature reached 10°C, the crystallized liquid was centrifuged in a closed centrifuge to obtain vinyl sulfate filter cake. The cake was then transferred to a fully automatic belt dryer for vacuum drying to obtain 334 kg of finished product with a yield of 83.52%, a purity of 99.68%, a moisture content of 31 ppm, and an acid value of 19 ppm.

[0071] In this embodiment, thionyl chloride and sodium chlorite were purchased from Shandong Shengze Chemical Co., Ltd. All other raw materials were commercially available products.

[0072] Example 4

[0073] The difference between this embodiment and Embodiment 3 is as follows: The preparation method of thionyl chloride is as follows: chlorine and sulfur are mixed in a molar ratio of 1:1.4 in a synthesizer at a temperature of 55°C to obtain disulfur dichloride. Disulfur dichloride is placed in a converter and chlorine with the same molar amount of sulfur is added. The mixture is then synthesized at a temperature of 70°C to obtain a mixed gas. The mixed gas is kept at 75°C and sent to a catalytic synthesizer containing activated carbon. At the same time, sulfur dioxide with 0.6 times the molar amount of sulfur is added. The mixture is catalytically synthesized at a temperature of 250°C to obtain thionyl chloride. The reactants are cooled to obtain crude thionyl chloride. The crude thionyl chloride is fed into a distillation vessel pre-filled with sulfur powder and distilled at a temperature of 110°C to obtain thionyl chloride with a purity of 99%.

[0074] The method for preparing sodium chlorite is as follows: 35 wt% hydrochloric acid aqueous solution is added to 33 wt% sodium chlorate aqueous solution, with a molar ratio of hydrochloric acid to sodium chlorate solution of 0.7:1. The mixed gas of chlorine dioxide and chlorine generated by the reaction is passed into an excess of 25 wt% sodium chlorite aqueous solution, with a molar ratio of chlorine to sodium chlorite of 1:2.7. Chlorine reacts with sodium chlorite to generate chlorine dioxide. Finally, chlorine dioxide gas is passed into 35 wt% sodium hydroxide aqueous solution, and 29 wt% hydrogen peroxide is added simultaneously to react and generate sodium chlorite, with a molar ratio of chlorine dioxide, sodium hydroxide and hydrogen peroxide of 1.9:1.9:1. Then, the mixture is crystallized and dried to generate solid sodium chlorite with a purity of 98%.

[0075] The yield of this embodiment is 85.76%, the purity is 99.85%, the moisture content is 30 ppm, and the acid value is 17 ppm.

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 3 is that 192 kg of thionyl chloride was added dropwise.

[0078] The comparative yield was 68.87%, the purity was 99.59%, the moisture content was 41 ppm, and the acid value was 34 ppm.

[0079] Comparative Example 2

[0080] The difference between this comparative example and Example 3 is that 1000 kg of thionyl chloride was added dropwise.

[0081] The comparative yield was 68.15%, the purity was 99.53%, the moisture content was 43 ppm, and the acid value was 32 ppm.

[0082] Comparative Example 3

[0083] The difference between this comparative example and Example 3 is that 75 kg of 30% hydrogen peroxide was added.

[0084] The comparative yield was 72.27%, the purity was 99.49%, the moisture content was 45 ppm, and the acid value was 31 ppm.

[0085] Comparative Example 4

[0086] The difference between this comparative example and Example 3 is that 274 kg of 30% hydrogen peroxide was added.

[0087] The comparative yield was 73.03%, the purity was 99.64%, the moisture content was 45 ppm, and the acid value was 33 ppm.

[0088] Comparative Example 5

[0089] The difference between this comparative example and Example 3 is that 1000 kg of a 30% sodium chlorite aqueous solution was added dropwise.

[0090] The comparative yield was 72.05%, the purity was 99.60%, the moisture content was 42 ppm, and the acid value was 34 ppm.

[0091] Comparative Example 6

[0092] The difference between this comparative example and Example 3 is as follows: The preparation method of thionyl chloride is as follows: chlorine and sulfur are mixed in a 1:1 molar ratio in a synthesizer at 55°C to obtain disulfur dichloride. Disulfur dichloride is placed in a converter and chlorine with the same molar amount of sulfur is added. The mixture is then synthesized at 70°C to obtain a mixed gas. The mixed gas is kept at 75°C and sent to a catalytic synthesizer containing activated carbon. At the same time, sulfur dioxide with the same molar amount of sulfur is added. The mixture is catalytically synthesized at 250°C to obtain thionyl chloride. The reactants are cooled to obtain crude thionyl chloride. The crude thionyl chloride is fed into a distillation vessel pre-filled with sulfur powder and distilled at 110°C to obtain thionyl chloride with a purity of 95%.

[0093] The comparative yield was 71.46%, the purity was 99.69%, the moisture content was 42 ppm, and the acid value was 31 ppm.

[0094] Comparative Example 7

[0095] The difference between this comparative example and Example 3 is as follows: The preparation method of sodium chlorite is as follows: 25 wt% hydrochloric acid aqueous solution is added to 30 wt% sodium chlorate aqueous solution, with a molar ratio of hydrochloric acid to sodium chlorate solution of 1:1. The mixed gas of chlorine dioxide and chlorine generated by the reaction is passed into an excess of 25 wt% sodium chlorite aqueous solution, with a molar ratio of chlorine to sodium chlorite of 1:2. Chlorine reacts with sodium chlorite to generate chlorine dioxide. Finally, chlorine dioxide gas is passed into 30 wt% sodium hydroxide aqueous solution, and 35 wt% hydrogen peroxide is added at the same time to generate sodium chlorite. The molar ratio of chlorine dioxide, sodium hydroxide and hydrogen peroxide is 2:2:1. Then, it is crystallized and dried to generate solid sodium chlorite with a purity of 95%.

[0096] The comparative yield was 72.33%, the purity was 99.70%, the moisture content was 41 ppm, and the acid value was 30 ppm.

[0097] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for the preparation of ethylene sulfate, characterized in that, The preparation method includes the following steps: (1) Acylation reaction: Add haloalkanes solvent and ethylene glycol to reaction vessel A, control the system temperature at 10-40℃, add thionyl chloride dropwise, and react for 0.5-2 h; after the reaction is complete, remove hydrogen chloride and solvent by vacuum distillation to obtain a haloalkanes solution containing ethylene sulfite, and put the haloalkanes solution containing ethylene sulfite into reaction vessel B for later use; the reaction equation is shown below: ； (2) Oxidation reaction: Add haloalkanes to reactor B, adjust the pH with buffer solution, add catalyst, control the solution temperature at 0-40℃, add hydrogen peroxide solution dropwise, then add sodium chlorite solution dropwise. After the addition is complete, continue the reaction for 1-60 min. After the reaction is complete, separate the contents, extract, wash, and dry to obtain a haloalkanes solution containing vinyl sulfate. Wash and dry the solution, concentrate it under low temperature and reduced pressure until the solution is saturated, add a poor solvent dropwise, cool down to crystallize, and filter to obtain crude vinyl sulfate. The reaction equation is shown below: ； (3) Refining and drying of vinyl sulfate: Dimethyl carbonate solvent is added to crude vinyl sulfate, stirred and heated until the solution is clear, filtered through a titanium rod filter to obtain filtrate, stirred and cooled to crystallize, centrifuged with a closed fully automatic centrifuge to obtain solid vinyl sulfate, and dried with a fully automatic belt dryer to obtain electronic grade standard finished product. In step (1), the molar ratio of thionyl chloride to ethylene glycol is 0.9-1.5:1; In step (1), thionyl chloride is added dropwise, and the acylation reaction is carried out at 10-80℃; After the reaction in step (1) is completed, the vacuum degree is 10 mmHg-500 mmHg, and the solvent is recovered; In step (2), the reaction buffer solution is selected from one or a combination of two of sodium carbonate, sodium bicarbonate, sodium dihydrogen phosphate, and sodium hydroxide. In step (2), the catalyst is selected from one of iron oxide, iron sulfate, and titanium silicate molecular sieve; The molar ratio of ethylene glycol to hydrogen peroxide in the hydrogen peroxide solution is 1:0.5-1.5; The molar ratio of ethylene glycol to sodium chlorite is 1:0.2-1.

5.

2. A process for the preparation of ethylene sulfate according to claim 1, characterized in that, In step (1), thionyl chloride is added dropwise, and the acylation reaction is carried out at 10-80℃.

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