Preparation method of ethylene sulfate

Abstract

The invention provides a preparation method of ethylene sulfate in order to solve the problems that in the prior art, ethylene glycol, thionyl chloride, sodium hypochlorite and ruthenium trichloride are used for preparing ethylene sulfate, cost is high, operation is complex, generated waste brine has adverse effects on the environment, and sodium ions and chloride ions in ethylene sulfate easily exceed standards. Comprising the following steps: mixing and heating concentrated sulfuric acid and ethylene glycol to carry out esterification reaction, continuously bubbling and introducing sulfur trioxide gas into a mixed solution composed of the concentrated sulfuric acid and the ethylene glycol in the esterification reaction process, and after the esterification reaction is finished, carrying out post-treatment to obtain the ethylene sulfate. According to the preparation method of the ethylene sulfate provided by the invention, the cost is low on the basis of obtaining higher yield, the technological process is simple to operate, the reaction conditions are milder, a dehydrating agent is not needed, sulfur trioxide can be recycled, three wastes are less, sodium ion and chloride ion impurities are not contained, and the purity of the ethylene sulfate is high.

Description

Technical Field

[0001] The present invention relates to the technical field of ethylene sulfate synthesis, and particularly to a preparation method of ethylene sulfate. Background Art

[0002] Ethylene sulfate (1,3,2-Dioxathiolane 2,2-dioxide, abbreviated as DTD) is a white crystal or crystalline powder, and its structural formula is: . In the field of lithium-ion batteries, ethylene sulfate is often used as an SEI film-forming additive. Ethylene sulfate can reduce the decline of battery capacity, inhibit the expansion of the battery after high-temperature discharge, reduce capacity attenuation and battery internal resistance, improve the low-temperature charge and discharge performance of the battery, improve the stability of the graphite negative electrode, and enhance the battery cycle performance. In the pharmaceutical field, ethylene sulfate can be used as a pharmaceutical intermediate, as a raw material for synthesizing a certain heterocyclic compound for gelatin hardening, antihypertensive drugs, and a new type of double surfactant, and has a broad market prospect.

[0003] Currently, the preparation methods of ethylene sulfate mainly include acylation method, substitution method, addition method, dioxane synthesis method, and oxidation method. Each of the above methods has its advantages and disadvantages. The advantage of the acylation method is that its raw materials are cheap and easily available, but the disadvantages are that the raw material thionyl chloride is harmful and the reaction yield is low. The oxidation method is a commonly used and relatively mature preparation method in industrial production. Starting from ethylene glycol, it first reacts with thionyl chloride to produce the intermediate ethylene sulfite, and then uses sodium hypochlorite as an oxidant and is catalyzed in an aqueous solution of ruthenium trichloride to obtain ethylene sulfate; the precious metal catalyst ruthenium trichloride used in this method is expensive and difficult to recycle, the sodium ions and chloride ions in the product ethylene sulfate are easy to exceed the standard, and a large amount of waste brine is generated by using sodium hypochlorite, which has an adverse impact on the environment, is not conducive to environmental protection, and does not meet the development requirements of green chemistry. Summary of the Invention

[0004] Aiming at the problems of high cost, complex operation, adverse environmental impact caused by the generation of waste brine, and easy excess of sodium ions and chloride ions in ethylene sulfate in the existing preparation of ethylene sulfate using ethylene glycol, thionyl chloride, sodium hypochlorite, and ruthenium trichloride, the present application provides a preparation method of ethylene sulfate.

[0005] The present invention provides a preparation method of ethylene sulfate, comprising the following steps: Mix concentrated sulfuric acid and ethylene glycol and heat them for an esterification reaction. During the esterification reaction, continuously bubble sulfur trioxide gas into the mixed solution composed of the concentrated sulfuric acid and the ethylene glycol. After the esterification reaction is completed, post-treatment is carried out to obtain the ethylene sulfate.

[0006] Preferably, in the step of continuously bubbling sulfur trioxide gas into the mixed solution composed of the concentrated sulfuric acid and the ethylene glycol during the esterification reaction, taking the amount of ethylene glycol as the quantification standard, the bubbling rate is 0.3719 - 0.7969 L / (kg·min).

[0007] Preferably, the bubbling rate is 0.4800 - 0.6200 L / (kg·min).

[0008] Preferably, in the step of heating for the esterification reaction, the esterification reaction temperature is 70 - 120 °C, and the esterification reaction time is 4 - 12 h.

[0009] Preferably, the esterification reaction temperature is 90 - 110 °C.

[0010] Preferably, the mass ratio of the concentrated sulfuric acid to the ethylene glycol is (0.1 - 0.5):1.

[0011] Preferably, after the esterification reaction, the post-treatment to obtain the vinyl sulfate includes the following steps: After the esterification reaction, extraction and liquid separation are carried out using a hydrophobic organic solvent to obtain an organic phase, and the organic phase is neutralized, washed with water, and concentrated and crystallized to obtain the vinyl sulfate.

[0012] Preferably, the hydrophobic organic solvent includes at least one of halogenated alkane organic solvents, alkane organic solvents, ether organic solvents, ester organic solvents, and aromatic organic solvents.

[0013] Preferably, the mass ratio of the hydrophobic organic solvent to the ethylene glycol is (3 - 15):1.

[0014] Preferably, in the step of continuously bubbling sulfur trioxide gas into the mixed solution composed of the concentrated sulfuric acid and the ethylene glycol during the esterification reaction, the temperature of the sulfur trioxide gas is 80 - 110 °C.

[0015] The method for preparing vinyl sulfate provided by this application uses concentrated sulfuric acid and ethylene glycol as raw materials, heats for the esterification reaction. During the esterification reaction, introducing sulfur trioxide gas can combine with the water generated during the esterification reaction of concentrated sulfuric acid and ethylene glycol to continue generating concentrated sulfuric acid, so as to continuously remove the water of the product. While promoting the forward reaction, it can reduce the hydrolysis of vinyl sulfate at high temperature. It can have a high yield, low cost, simple process operation, mild reaction conditions, no need to use a dehydrating agent, sulfur trioxide can be reused, less three wastes, no sodium ion and chloride ion impurities, and high purity of vinyl sulfate. Specific embodiments

[0016] In order to make the objectives, technical solutions, and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] In order to illustrate the technical solution of the present invention, specific embodiments will be used for illustration below.

[0018] In an embodiment of the present invention, a method for preparing ethylene sulfate includes the following steps: Mix concentrated sulfuric acid and ethylene glycol and heat them for an esterification reaction. During the esterification reaction, sulfur trioxide gas is continuously bubbled into the mixed solution composed of concentrated sulfuric acid and ethylene glycol. After the esterification reaction is completed, post-treatment is carried out to obtain the ethylene sulfate.

[0019] Specifically, during the esterification reaction, sulfur trioxide gas is continuously bubbled into the mixed solution composed of concentrated sulfuric acid and ethylene glycol. By heating at a high temperature, sulfur trioxide undergoes a phase change into a gas. The gaseous sulfur trioxide reacts with the water generated during the esterification reaction to form concentrated sulfuric acid, which not only realizes the function of removing water but also continues to maintain the concentration of the reactant concentrated sulfuric acid, enabling the reaction to always proceed in the forward direction. The excess sulfur trioxide gas can be condensed to remove impurities and then reheated and enter the circulation system again, achieving full recovery and utilization.

[0020] The method for preparing ethylene sulfate provided by the present application uses concentrated sulfuric acid and ethylene glycol as raw materials and heats them for an esterification reaction. During the esterification reaction, introducing sulfur trioxide gas can combine with the water generated during the esterification reaction of concentrated sulfuric acid and ethylene glycol to continue generating concentrated sulfuric acid to continuously remove the water of the product. While promoting the forward reaction, it reduces the hydrolysis of ethylene sulfate at high temperatures. It can have a high yield while being low in cost, simple in process operation, mild in reaction conditions, without the need to use a dehydrating agent, and sulfur trioxide can be reused, with less three wastes and no sodium ion and chloride ion impurities, and the purity of ethylene sulfate is high.

[0021] The method for preparing ethylene sulfate provided by the present application not only makes the preparation process relatively green and environmentally friendly but also does not have difficult-to-treat or highly polluting three wastes. It has low requirements for equipment, simple process operation, relatively mild reaction conditions, less sulfur trioxide usage and easy separation and recovery, making the overall process cost relatively low and facilitating large-scale industrial production.

[0022] In some embodiments, in the step of continuously bubbling sulfur trioxide gas into the mixed solution composed of concentrated sulfuric acid and ethylene glycol during the esterification reaction, based on the amount of ethylene glycol as a quantification standard, the bubbling rate is 0.3719 - 0.7969 L / (kg·min).

[0023] Specifically, during the esterification reaction, sulfur trioxide gas is continuously introduced into the mixed solution composed of concentrated sulfuric acid and ethylene glycol. When the sulfur trioxide gas enters the liquid, it forms bubbles, and these bubbles move upward in the liquid to form bubbles, realizing the bubbling operation. This is conducive to the reaction of the introduced sulfur trioxide gas with the water generated by the esterification reaction of concentrated sulfuric acid and ethylene glycol to generate concentrated sulfuric acid, achieving the purpose of water removal and also helping to promote the forward progress of the reaction.

[0024] Taking the amount of ethylene glycol as the quantification standard, the bubbling rate is 0.3719 - 0.7969 L / (kg·min). The specific meaning is that in each minute, for every 1 kg of the reactant ethylene glycol, 0.3719 - 0.7969 L of sulfur trioxide gas is introduced into the mixed solution composed of concentrated sulfuric acid and ethylene glycol for bubbling.

[0025] The inventors found through a large number of experiments that the introduction rate of sulfur trioxide gas has a significant impact on the rate of this esterification reaction and the yield of the product. When the introduction rate of sulfur trioxide gas is too slow, the reaction rate is slow, and the reaction stops proceeding after reaching a certain extent and reaches equilibrium; when the introduction rate of sulfur trioxide gas is too fast, the product of the esterification reaction is prone to turning black and is extremely difficult to purify, and the reaction waste also increases significantly. The inventors found through research that when the ventilation rate of sulfur trioxide gas corresponding to each kilogram of the reactant ethylene glycol is in the range of 0.3719 - 0.7969 L / min, the reaction rate of the esterification reaction is relatively high, and the yield of the obtained product ethylene sulfate is high; the yield of the product ethylene sulfate can reach more than 90%.

[0026] Specifically, the bubbling rate can be in the following ranges: 0.3719 - 0.4 L / (kg·min), 0.4 - 0.5 L / (kg·min), 0.5 - 0.6 L / (kg·min), or 0.6 - 0.7969 L / (kg·min).

[0027] In some preferred embodiments, the bubbling rate is 0.4800 - 0.6200 L / (kg·min). When the bubbling rate of sulfur trioxide gas is in the range of 0.4800 - 0.6200 L / (kg·min), the esterification reaction rate of concentrated sulfuric acid and ethylene glycol is faster, the esterification reaction time is short, and the yield of the generated product ethylene sulfate is higher.

[0028] Further preferably, the bubbling rate is 0.5000 - 0.6000 L / (kg·min).

[0029] In some embodiments, during the step of continuously introducing sulfur trioxide gas for bubbling into the mixed solution composed of concentrated sulfuric acid and ethylene glycol during the esterification reaction, the temperature of the sulfur trioxide gas is 80 - 110 °C.

[0030] Specifically, controlling the temperature of sulfur trioxide gas within the range of 80-110°C is beneficial for the reaction of sulfur trioxide with water to form sulfuric acid, which can effectively and rapidly remove the water generated by the esterification reaction, and the yield of ethylene sulfate obtained is high.

[0031] The temperature of sulfur trioxide gas can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, etc., as long as the temperature of sulfur trioxide gas is within the range of 80-110°C.

[0032] In some embodiments, during the esterification reaction step with heating, the esterification reaction temperature is 70-120°C, and the esterification reaction time is 4-12 h.

[0033] Specifically, the esterification reaction temperature can be 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, etc., as long as the esterification reaction temperature is within the range of 70-120°C. The esterification reaction time can be 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7.0 h, 7.5 h, 8.0 h, 8.5 h, 9.0 h, 9.5 h, 10.0 h, 10.5 h, 11.0 h, 11.5 h, 12.0 h, etc., as long as the esterification reaction time is within the range of 4-12 h.

[0034] Within the range of the esterification reaction temperature of 70-120°C and the esterification reaction time of 4-12 h, ethylene glycol and concentrated sulfuric acid can undergo an esterification reaction to form ethylene sulfate, and at the same time, sulfur trioxide can react with water to form sulfuric acid, enabling the reaction to proceed in the forward direction; compared with the existing ethylene sulfate preparation process, the preparation time is greatly shortened, and the production efficiency can be significantly improved.

[0035] If the esterification reaction temperature is lower than 70°C, the temperature is too low, which affects the esterification reaction rate. If the esterification reaction temperature is higher than 120°C, the temperature is too high, which affects the reaction of sulfur trioxide with water, affects the forward progress of the esterification reaction, and affects the esterification reaction rate.

[0036] In some preferred embodiments, the esterification reaction temperature is 90-110°C.

[0037] Specifically, within the range of the esterification reaction temperature of 90-110°C, the esterification reaction rate is relatively fast, and it is also beneficial for sulfur trioxide gas to react with water to form sulfuric acid, effectively consuming the water generated during the esterification reaction process.

[0038] In some embodiments, the mass ratio of concentrated sulfuric acid to ethylene glycol is (0.1-0.5):1.

[0039] Specifically, limiting the mass ratio of concentrated sulfuric acid to ethylene glycol to the range of (0.1~0.5):1 is beneficial to the esterification reaction of ethylene glycol and concentrated sulfuric acid to produce ethylene sulfate. The mass ratio of concentrated sulfuric acid to ethylene glycol can be 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, etc. As long as the mass ratio of concentrated sulfuric acid to ethylene glycol is within the range of (0.1~0.5):1, it is acceptable.

[0040] If the mass ratio of concentrated sulfuric acid to ethylene glycol is lower than (0.1~0.5):1, too little concentrated sulfuric acid is added, and the esterification reaction rate decreases; if the mass ratio of concentrated sulfuric acid to ethylene glycol is higher than (0.1~0.5):1, too little ethylene glycol is added, and the esterification reaction rate decreases.

[0041] In some embodiments, the post-treatment after the esterification reaction to obtain the ethylene sulfate includes the following steps: After the esterification reaction, extraction and liquid separation are carried out using a hydrophobic organic solvent to obtain an organic phase, and the organic phase is neutralized, washed with water, concentrated and crystallized to obtain the ethylene sulfate.

[0042] Specifically, after the esterification reaction, the temperature is first lowered to room temperature, and then a hydrophobic organic solvent is added for extraction and liquid separation to obtain an organic phase. The solubility of unreacted ethylene glycol and concentrated sulfuric acid in the hydrophobic organic solvent is small, and water is insoluble in the hydrophobic organic solvent. Extraction separation can remove water, part of the concentrated sulfuric acid and ethylene glycol, and the obtained organic phase contains less ethylene glycol and concentrated sulfuric acid.

[0043] The ethylene glycol in water can be recovered by rectification extraction.

[0044] The organic phase is neutralized, that is, a pH regulator is added to the organic phase to react with concentrated sulfuric acid to form a salt soluble in water. The pH regulator is a weakly alkaline solution, and the weakly alkaline solution includes a sodium bicarbonate solution.

[0045] The neutralized organic phase is washed with water to further remove water-soluble impurities such as salts and ethylene glycol.

[0046] After the water washing of the organic phase, concentration and crystallization are carried out to obtain ethylene sulfate with higher purity.

[0047] The hydrophobic organic solvent includes at least one of halogenated alkane organic solvents, alkane organic solvents, ether organic solvents, ester organic solvents, and aromatic organic solvents.

[0048] Specifically, the hydrophobic organic solvent is used to remove water, unreacted ethylene glycol, and concentrated sulfuric acid impurities.

[0049] In some embodiments, the halogenated alkane organic solvents include one or more of dichloromethane and carbon tetrachloride.

[0050] In some embodiments, the alkane organic solvents include n-hexane.

[0051] In some embodiments, the ether organic solvents include diethyl ether.

[0052] In some embodiments, the ester organic solvents include ethyl acetate.

[0053] In some embodiments, the aromatic organic solvents include at least one of benzene and toluene.

[0054] In some embodiments, the mass ratio of the hydrophobic organic solvent to ethylene glycol is (3 - 15):1.

[0055] Specifically, within the range of the mass ratio of the hydrophobic organic solvent to ethylene glycol being (3 - 15):1, it helps to remove impurities such as water, concentrated sulfuric acid, and ethylene glycol, and at the same time dissolve the generated ethylene sulfate, improving the yield of the product ethylene sulfate. If the mass ratio of the hydrophobic organic solvent to ethylene glycol is lower than or higher than the range of (3 - 15):1, the yield of the ethylene sulfate product obtained is relatively low.

[0056] The mass ratio of the hydrophobic organic solvent to ethylene glycol can be 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 15:1, etc., as long as the mass ratio of the hydrophobic organic solvent to ethylene glycol is within the range of (3 - 15):1.

[0057] The present invention will be further described below through examples.

[0058] Example 1 This example provides a method for preparing ethylene sulfate, and the specific steps are as follows: S1: Add 3.0 kg of ethylene glycol to the reaction vessel, slowly drop 1.0 kg of concentrated sulfuric acid into the reaction vessel, heat to 110°C, then stir at 200 rpm, and bubble sulfur trioxide gas at a temperature of 110°C into the mixed solution of ethylene glycol and concentrated sulfuric acid formed by every kilogram of ethylene glycol reactant, with a bubbling rate of 0.4800 L / (kg·min), control the reaction temperature of the esterification reaction to be 110°C, and the esterification reaction time to be 6 h.

[0059] S2: After the esterification reaction in step S1 is completed, the temperature is decreased to 30°C, then 20 kg of dichloromethane is added for extraction. After stirring for 30 minutes, liquid separation is performed to obtain the organic phase. 4 kg of aqueous sodium bicarbonate solution is added to the organic phase for neutralization. After neutralization, liquid separation is carried out. 4 kg of pure water is added to the neutralized organic phase for washing and liquid separation again. The washing is repeated twice.

[0060] S3: The organic phase after the washing in step S2 is concentrated and crystallized to obtain the product.

[0061] Example 2 Most of the steps in this example are the same as those in Example 1. The difference is that the bubbling rate of sulfur trioxide gas in step S1 is different. The bubbling rate in Example 2 is 0.3719 L / (kg·min). The rest is the same as in Example 1.

[0062] Example 3 Most of the steps in this example are the same as those in Example 1. The difference is that the bubbling rate of sulfur trioxide gas in step S1 is different. The bubbling rate in Example 3 is 0.6200 L / (kg·min). The rest is the same as in Example 1.

[0063] Example 4 Most of the steps in this example are the same as those in Example 1. The difference is that the bubbling rate of sulfur trioxide gas in step S1 is different. The bubbling rate in Example 4 is 0.7969 L / (kg·min). The rest is the same as in Example 1.

[0064] Example 5 Most of the steps in this example are the same as those in Example 1. The difference is that the bubbling rate of sulfur trioxide gas in step S1 is different. The bubbling rate in Example 5 is 0.3200 L / (kg·min). The rest is the same as in Example 1.

[0065] Example 6 Most of the steps in this example are the same as those in Example 1. The difference is that the bubbling rate of sulfur trioxide gas in step S1 is different. The bubbling rate in Example 6 is 0.8200 L / (kg·min). The rest is the same as in Example 1.

[0066] Example 7 Most of the steps in this example are the same as those in Example 1. The difference is that in step S1 of Example 7, the esterification reaction temperature is 90°C, the esterification reaction time is 8 h, and the temperature of the sulfur trioxide gas introduced is 90°C. The rest is the same as in Example 1.

[0067] Example 8 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In the esterification reaction in step S1 of Example 8, the reaction temperature is 120 °C, the reaction time is 4 h, and the temperature of the sulfur trioxide gas introduced is 100 °C. The rest is the same as in Example 1.

[0068] Example 9 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In the esterification reaction in step S1 of Example 9, the reaction temperature is 70 °C, and the temperature of the sulfur trioxide gas introduced is 80 °C. The rest is the same as in Example 1.

[0069] Example 10 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In the esterification reaction in step S1 of Example 10, the reaction temperature is 130 °C, the reaction time is 6 h, and the temperature of the sulfur trioxide gas introduced is 100 °C. The rest is the same as in Example 1.

[0070] Example 11 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In the esterification reaction in step S1 of Example 11, the reaction temperature is 60 °C, the reaction time is 6 h, and the temperature of the sulfur trioxide gas introduced is 80 °C. The rest is the same as in Example 1.

[0071] Example 12 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In step S1 of Example 12, the temperature of the sulfur trioxide gas introduced is 70 °C. The rest is the same as in Example 1.

[0072] Example 13 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In step S1 of Example 13, the temperature of the sulfur trioxide gas introduced is 120 °C. The rest is the same as in Example 1.

[0073] Example 14 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In step S1 of Example 14, the mass of concentrated sulfuric acid is 1.5 kg. The rest is the same as in Example 1.

[0074] Example 15 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In step S1 of Example 15, the mass of concentrated sulfuric acid is 0.2 kg. The rest is the same as in Example 1.

[0075] Example 16 Most of the steps in this example are the same as those in Example 1. The differences are as follows: In step S2 of Example 16, the mass of dichloromethane is 6 kg. The rest is the same as in Example 1.

[0076] Comparative Example 1 Most steps of this Comparative Example 1 are the same as those of Example 1, and the differences are as follows: The S1 step in Comparative Example 1 is different. Specifically, 3.0 kg of ethylene glycol was added to the reaction vessel, 1.0 kg of concentrated sulfuric acid was slowly dropped into the reaction vessel, and after heating to 110 °C, an esterification reaction was carried out, and the esterification reaction time was 6 h. The S2 and S3 steps are the same as those of Example 1.

[0077] Calculate the esterification reaction conversion rate (calculated based on concentrated sulfuric acid), the yield of the product, and test the purity or content of ethylene sulfate in the products obtained in the above examples and comparative examples. The recorded results are shown in Table 1.

[0078] Table 1 From the test results in Table 1, it can be seen that when comparing Example 1 and Comparative Example 1, in Comparative Example 1, no high-temperature sulfur trioxide was bubbled in, and the yield of the ethylene sulfate product obtained was low, and the content of ethylene sulfate in the product was low. This shows that in the preparation method of ethylene sulfate provided in this application, during the esterification reaction process, introducing sulfur trioxide gas can combine with the water generated during the esterification reaction of concentrated sulfuric acid and ethylene glycol to continuously generate concentrated sulfuric acid, so as to achieve the purpose of continuously removing the generated water, promote the forward reaction, and at the same time improve the yield and purity of ethylene sulfate.

[0079] When comparing Examples 1-4 and Examples 5-6, the bubbling rate of Example 5 is lower than 0.3719 L / (kg·min), resulting in a low esterification reaction conversion rate, a low yield of the ethylene sulfate product, and a low purity. It is speculated that when the introduction rate of sulfur trioxide gas is too slow, the reaction rate is slow, and the reaction stops proceeding after reaching a certain extent and reaches equilibrium; the bubbling rate of Example 6 is higher than 0.7969 L / (kg·min), resulting in a low esterification reaction conversion rate, an even lower yield of the ethylene sulfate product, and a lower purity. It is speculated that when the introduction rate of sulfur trioxide gas is too fast, the product of the esterification reaction is prone to blackening and extremely difficult to purify; it shows that during the esterification reaction process, sulfur trioxide gas is continuously bubbled into the mixed solution composed of concentrated sulfuric acid and ethylene glycol. Taking the amount of ethylene glycol as the quantification standard, when the bubbling rate is in the range of 0.3719-0.7969 L / (kg·min), the esterification reaction conversion rate is high, the yield of the obtained ethylene sulfate product is high, and the purity of ethylene sulfate is high. Further preferably, when the bubbling rate is in the range of 0.4800-0.6200 L / (kg·min), the yield and purity of the obtained ethylene sulfate product are high.

[0080] Comparisons between Example 1, Examples 7 - 9 and Examples 10 - 11 show that when the esterification temperature is lower than 70°C, the esterification reaction is incomplete; when the esterification temperature is higher than 120°C, there are many side reactions. When the esterification temperature is in the range of 70 - 120°C, the conversion rate of the esterification reaction is high, the yield of the vinyl sulfate product obtained is high, and the purity of the vinyl sulfate is high. When the esterification temperature is in the range of 90 - 110°C, the yield of the vinyl sulfate product obtained is even higher, and the purity of the vinyl sulfate is relatively high.

[0081] Comparisons between Example 1 and Examples 12, 13 show that when the temperature of sulfur trioxide gas is lower than 80°C, the conversion rate of the esterification reaction is low, the product yield is low, and the purity is slightly low; when the temperature of sulfur trioxide gas is higher than 110°C, the conversion rate of the esterification reaction is low, the product yield is low, and the purity is even lower. This shows that when the temperature of sulfur trioxide gas is in the range of 80 - 110°C, the conversion rate of the esterification reaction is high, the yield of the vinyl sulfate product obtained is high, and the purity of the vinyl sulfate is high.

[0082] Comparisons between Example 1, Example 14 and Example 15 show that when the mass ratio of concentrated sulfuric acid to ethylene glycol is lower than (0.1 - 0.5):1, the conversion rate of the esterification reaction is low, the yield of the vinyl sulfate product obtained is relatively low, and the product purity is low. This shows that when the mass ratio of concentrated sulfuric acid to ethylene glycol is in the range of (0.1 - 0.5):1, the conversion rate of the esterification reaction is high, the yield of the vinyl sulfate product obtained is high, and the purity of the vinyl sulfate is high.

[0083] Comparisons between Example 1 and Example 16 show that when the amount of extraction solvent used is too small, the product yield and purity decrease; when the mass ratio of the hydrophobic organic solvent to ethylene glycol is in the range of (3 - 15):1, the conversion rate of the esterification reaction is high, the yield of the vinyl sulfate product obtained is high, and the purity of the vinyl sulfate is high.

[0084] The above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for preparing ethylene sulfate, characterized in that, It includes the following steps: Mix concentrated sulfuric acid and ethylene glycol and heat them for an esterification reaction. During the esterification reaction, continuously bubble sulfur trioxide gas into the mixed solution composed of the concentrated sulfuric acid and the ethylene glycol. After the esterification reaction is completed, post-treatment is carried out to obtain the vinyl sulfate.

2. The preparation method of vinyl sulfite according to claim 1, characterized in that, In the step of continuously bubbling sulfur trioxide gas into the mixed solution composed of the concentrated sulfuric acid and the ethylene glycol during the esterification reaction, taking the amount of the ethylene glycol as the quantification standard, the bubbling rate is 0.3719 - 0.7969 L / (kg·min).

3. The preparation method of vinylene sulfate according to claim 2, characterized in that, The bubbling rate is 0.4800 - 0.6200 L / (kg·min).

4. The preparation method of vinylene sulfate according to claim 1, characterized in that In the step of heating for the esterification reaction, the esterification reaction temperature is 70 - 120 °C, and the esterification reaction time is 4 - 12 h.

5. The preparation method of vinylene sulfate according to claim 4, characterized in that, The esterification reaction temperature is 90 - 110 °C.

6. The method for preparing vinyl sulfate according to claim 1, wherein The mass ratio of the concentrated sulfuric acid to the ethylene glycol is (0.1 - 0.5):

1.

7. The preparation method of vinylene sulfate according to claim 1, wherein The post-treatment after the esterification reaction to obtain the vinyl sulfate includes the following steps: After the esterification reaction is completed, extraction and liquid separation are carried out using a hydrophobic organic solvent to obtain an organic phase. The organic phase is neutralized, washed with water, concentrated and crystallized to obtain the vinyl sulfate.

8. The method for preparing vinylene sulfate according to claim 7, characterized in that, The hydrophobic organic solvent includes at least one of halogenated alkane organic solvents, alkane organic solvents, ether organic solvents, ester organic solvents, and aromatic organic solvents.

9. The preparation method of vinylene sulfate according to claim 7, wherein, The mass ratio of the hydrophobic organic solvent to the ethylene glycol is (3 - 15):

1.

10. The method for preparing ethylene sulfate according to claim 1, wherein In the step of continuously bubbling sulfur trioxide gas into the mixed solution composed of the concentrated sulfuric acid and the ethylene glycol during the esterification reaction, the temperature of the sulfur trioxide gas is 80 - 110 °C.

Images