Method for continuously preparing ethylene sulfate

Abstract

The invention relates to a method for continuously preparing ethylene sulfate, and belongs to the field of organic chemical industry. The method comprises the following steps: firstly, modifying titanium silicalite molecular sieve particles by adopting a silane coupling agent and nano aluminum trifluoride to obtain titanium silicalite molecular sieve particles with a hydrophobic acidic shell as a catalyst, filling the catalyst into a tower reactor, and adding ethylene oxide and sulfur dioxide into a first mixer and a first preheater; feeding into a tower type fixed bed reactor from the tower bottom under a certain pressure, and reacting under the catalysis of a catalyst hydrophobic acidic shell to obtain ethylene sulfite; hydrogen peroxide and chloroform enter the fixed bed tower reactor from the tower top after passing through a second mixer and a second preheater, and are subjected to oxidation reaction with ethylene sulfite to obtain ethylene sulfate. The ethylene sulfate is prepared in a continuous manner, so that the reaction time is shortened, and the production efficiency and the production safety are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical synthesis, and particularly relates to a method for continuously preparing ethylene sulfate. Background Art

[0002] Ethylene sulfate is an important fine chemical product, which is widely used in fields such as batteries, pharmaceuticals, plastics, coatings, and adhesives. The market scale is huge, with an annual output of more than 1 million. With the continuous development of the new energy industry, the demand for lithium battery electrolyte additives is increasing day by day. As an important additive for lithium battery electrolytes, the main functions of ethylene sulfate include improving the initial discharge capacity of lithium-ion batteries, reducing discharge swelling, extending the battery life, and improving its performance at high and low temperatures. In addition, ethylene sulfate is also used as a raw material for organic synthetic drug intermediates, heterocyclic compounds, antihypertensive drugs, and new double surfactants. With the rapid development of the new energy vehicle industry represented by lithium-ion batteries, the uses of ethylene sulfate are becoming more and more extensive, and the market demand is increasing. Therefore, an efficient, safe, and environmentally friendly preparation method for ethylene sulfate has received extensive attention.

[0003] There are many synthetic routes for ethylene sulfate. At present, the industrial production of ethylene sulfate mostly adopts a two-step process, that is, first synthesize ethylene sulfite, and then catalytically oxidize ethylene sulfite to ethylene sulfate. There are currently two main methods for the synthesis process of oxidizing ethylene sulfite to ethylene sulfate: sodium hypochlorite / ruthenium trichloride catalytic oxidation and hydrogen peroxide / titanium silicate molecular sieve catalytic oxidation. At present, the sodium hypochlorite / ruthenium trichloride catalytic oxidation process (CN107973774A, CN118142458A) is commonly used in China because sodium hypochlorite is relatively inexpensive. In addition, sodium hypochlorite has strong oxidizing properties and high oxidation efficiency, with fewer impurities, and the by-product sodium chloride is easy to remove from water. The disadvantages of this process route are that the catalyst ruthenium trichloride is relatively expensive, the recovery steps are cumbersome, the concentration of sodium hypochlorite is low, and the amount of salt-containing wastewater generated is large, which does not conform to green economic chemistry.

[0004]

[0005] The hydrogen peroxide / titanium silicalite (TS-1) catalytic oxidation process has the unique by-product of water after hydrogen peroxide oxidation, which makes the hydrogen peroxide / TS-1 catalytic oxidation process far more environmentally friendly than the sodium hypochlorite / ruthenium trichloride catalytic oxidation process. Unfortunately, there are few literature reports on this process at present, and the process is still in the experimental development stage. The more environmentally friendly and cleaner hydrogen peroxide / TS-1 oxidation method for preparing vinyl sulfate is hindered by problems such as long reaction time, low selectivity, and catalyst deactivation, and cannot replace the existing sodium hypochlorite / ruthenium oxide oxidation method. CN109422719A and CN118388444A reported the catalytic oxidation of vinyl sulfite to vinyl sulfate using a TS-1 and hydrogen peroxide system. The TS-1 in this reaction system was not specifically modified. Due to the failure to effectively solve the hydrolysis problems of the product and hydrogen peroxide, traditional TS-1 is not an efficient and stable catalyst for this reaction system. In addition, the two-step synthesis of vinyl sulfate has high costs, cumbersome steps, low synthesis efficiency, etc., which have become key problems hindering its industrial scale-up. Summary of the Invention

[0006] In order to solve the problems existing in the existing production methods of vinyl sulfate, the present invention proposes a continuous process route for synthesizing vinyl sulfate.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for continuously preparing vinyl sulfate, comprising the following steps:

[0009] (1) Add mesoporous template agent and tetraethyl orthosilicate to ethanol, stir and disperse evenly, add granular titanium silicalite, stir at room temperature for 1-3 hours, heat up to 40°C - 60°C, slowly add silane coupling agent and nano aluminum trifluoride, stir for 6-12 hours, separate the solid and liquid, wash with ethanol, and dry the obtained solid at 100-200°C for 3-9 hours to obtain a titanium silicalite catalyst, and load the obtained catalyst into a tower fixed bed reactor;

[0010] (2) Feed ethylene oxide and sulfur dioxide into the tower fixed bed reactor filled with catalyst through a first mixer and a first preheater for reaction to obtain a vinyl sulfite reaction solution;

[0011] (3) Feed hydrogen peroxide and chloroform into the tower reactor filled with catalyst through a second mixer and a second preheater for reaction. The tail gas at the top of the tower is recycled, and the liquid flowing out from the bottom of the tower is a reaction solution containing vinyl sulfate. After liquid separation, vacuum distillation concentration and freeze crystallization, collect the solid to obtain vinyl sulfate product.

[0012] Further, in the step (1), the mesoporous template agent is one or more of cetyltrimethylammonium bromide, dodecyltrimethylammonium bromide, Triton X-100, Tween, and polydiallyldimethylammonium chloride. More preferably, it is cetyltrimethylammonium bromide. The mesoporous template agent can introduce ordered mesopores into the shell, improving the diffusion efficiency of the substrate and the utilization efficiency of active sites.

[0013] Further, in the step (1), the granular titanium silicalite molecular sieve is one or more of TS-1, Ti-MWW, and Ti-MOR. More preferably, it is TS-1.

[0014] Further, in the step (1), the particle size of the granular titanium silicalite molecular sieve is 1-5 mm. More preferably, it is 2-3 mm.

[0015] Further, in the step (1), the silane coupling agent is one or more of hexamethyldisilazane, trimethylchlorosilane, trifluoroethyltriethoxysilane, methoxytrimethylsilane, and tetramethyldisilazane. More preferably, it is hexamethyldisilazane.

[0016] Further, in the step (1), the molar ratio of tetraethyl orthosilicate, silane coupling agent, nanoaluminum trifluoride to the granular titanium silicalite molecular sieve is tetraethyl orthosilicate∶silane coupling agent∶nanoaluminum trifluoride∶granular titanium silicalite molecular sieve (calculated as SiO2)=0.05-0.13∶0.03-0.10∶0.02-0.08∶1.

[0017] Further, in the step (1), the molar ratio of the mesoporous template agent to the titanium silicalite molecular sieve (calculated as SiO2) is 0.02-0.07∶1.

[0018] Further, in the step (2), the molar ratio of sulfur dioxide to ethylene oxide is 1.2-1.5∶1, and the space velocity of the mixed gas is (gas mass standard condition volume flow / catalyst bed volume) 300-1400 h -1 。

[0019] Further, in the step (3), the hydrogen peroxide concentration in hydrogen peroxide is 27.5 wt% to 50 wt%. More preferably, it is 35 wt%.

[0020] Further, in the step (3), the volume ratio of hydrogen peroxide to chloroform is 1∶5-10, the molar ratio of hydrogen peroxide to ethylene oxide is 1.1-1.5∶1, and the space velocity of the mixed liquid (mixed liquid mass flow / catalyst bed mass) is 3-12 h -1 。

[0021] Further, in the steps (2) and (3), the reaction temperature in the tower fixed bed reactor is 30-50 °C, and the reaction pressure is 0.2-2 MPa.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. By using ethylene oxide, sulfur dioxide, and hydrogen peroxide as starting materials and carrying out an in-situ catalytic reaction with a modified titanium silicalite molecular sieve, vinyl sulfate is synthesized in one step. The process flow is simple, the post-treatment method is convenient, the emissions of three wastes are low, the production cost is low, and it has high industrialization value.

[0024] 2. The present invention adopts a tower-type fixed-bed reaction device to realize the continuous preparation of vinyl sulfate, greatly improving the problems of low synthesis efficiency, unstable process, and inherent safety problems existing in the existing process.

[0025] 3. By constructing a modified titanium silicalite molecular sieve catalyst, the silane coupling agent and aluminum trifluoride have hydrophobicity and acidity respectively. The silane coupling agent can enrich the reactants, improve the reaction conversion efficiency, reduce the hydrolysis problem of the products and intermediates, improve the selectivity of the products and the process safety, and aluminum trifluoride and titanium silicalite molecular sieve can effectively catalyze the occurrence of the reaction to realize the in-situ catalytic one-step synthesis of vinyl sulfate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process schematic diagram of the method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The technical solutions and effects of the present invention will be further described below in conjunction with the drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0028] All raw materials used in the present invention are commercially available products, and the tower-type fixed-bed reactor belongs to existing equipment, and its detailed structure will not be described in detail in the present invention.

[0029] In the following examples and comparative examples, the hydrogen peroxide concentration in hydrogen peroxide is 35 wt%. In view of the fact that the SiO2 content in TS-1, Ti-MWW, and Ti-MOR titanium silicalite molecular sieves exceeds 97%, for the convenience of calculation, in the following examples and comparative examples, the molar amount of SiO2 is calculated based on the mass of the molecular sieve.

[0030] Example 1

[0031] The method for continuously preparing vinyl sulfate in this example includes the following steps:

[0032] (1) Preparation of titanium silicalite molecular sieve catalyst: Add 15 Kg of cetyltrimethylammonium bromide and 15 Kg of tetraethyl orthosilicate into 500 L of ethanol, stir and disperse evenly, add 50 Kg of TS-1 type titanium silicalite molecular sieve, stir at room temperature for 2 hours, heat up to 42 - 45 °C, add 6.25 Kg of hexamethyldisilazane and 3 Kg of nanoaluminum trifluoride, stir for 8 hours, separate the solid and liquid, wash the solid with ethanol, and dry at 120 °C for 6 hours to obtain the modified TS-1 type molecular sieve catalyst.

[0033] (2) Add 13 Kg of the modified TS-1 type molecular sieve catalyst into a tower fixed-bed reactor, prepare sufficient ethylene oxide, prepare a high-pressure sulfur dioxide gas cylinder for use, set the back pressure valve pressure to 1.5 Mpa, the molar ratio of sulfur dioxide to ethylene oxide is 1.3∶1, connect the above-mentioned liquid material to a feed pump, mix through a first mixer and preheat through a first preheater, then enter from the bottom of the tower fixed-bed reactor, and the space velocity of the mixed gas is (gas mass standard condition volume flow / catalyst bed volume) 800 h -1 , and control the reaction temperature at 40 - 43 °C.

[0034] (3) Feed hydrogen peroxide and chloroform through a plunger pump, where the molar ratio of hydrogen peroxide to ethylene oxide is 1.2∶1, the volume ratio of hydrogen peroxide to chloroform is 1∶5, and the volume space velocity is 6 h -1 (mixed liquid mass flow / catalyst bed mass), the reaction liquid is preheated through a second mixer and a second preheater and then enters from the top of the reactor, the reaction temperature is 40 - 43 °C, the reaction pressure is 1.5 Mpa, the reaction liquid flows out from the bottom of the tower, is separated, subjected to vacuum distillation and crystallization to obtain the finished product of ethylene sulfate, with a purity of 99.35% and a molar yield of 85.21%.

[0035] Example 2

[0036] The continuous preparation method of ethylene sulfate in this example includes the following steps:

[0037] (1) Preparation of titanium silicalite molecular sieve catalyst: Add 12.5 Kg of cetyltrimethylammonium bromide and 15 Kg of tetraethyl orthosilicate into 250 L of ethanol, stir and disperse evenly, add 50 Kg of Ti-MWW type molecular sieve, stir at room temperature for 2 hours, heat up to 42 - 45 °C, add 6.25 Kg of hexamethyldisilazane and 3 Kg of nanoaluminum trifluoride, stir for 6 hours, separate the solid and liquid, wash the solid with ethanol, and dry at 120 °C for 6 hours to obtain the modified Ti-MWW type molecular sieve catalyst.

[0038] (2) Add 10 Kg of the modified Ti-MWW type molecular sieve catalyst into a tower-type fixed bed reactor. Prepare sufficient ethylene oxide and get a high-pressure sulfur dioxide gas cylinder ready for use. Set the back pressure valve pressure to 1.5 Mpa. The molar ratio of sulfur dioxide to ethylene oxide is 1.3∶1. Connect the above-mentioned liquid material to a feed pump, mix it through a first mixer and preheat it through a first preheater, and then enter from the bottom of the tower-type fixed bed reactor. The space velocity of the mixed gas is (gas mass standard condition volume flow rate / catalyst bed volume) 800 h -1 and control the reaction temperature at 40 - 43 °C.

[0039] (3) Feed hydrogen peroxide and chloroform through a plunger pump. The molar ratio of hydrogen peroxide to ethylene oxide is 1.2∶1, and the volume ratio of hydrogen peroxide to chloroform is 1∶5. The volume space velocity is 4 h -1 (mixed liquid mass flow rate / catalyst bed mass). The reaction liquid is preheated through a second mixer and a second preheater and then enters from the top of the reactor. The reaction temperature is 40 - 43 °C, and the reaction pressure is 1.6 Mpa. After the reaction liquid flows out from the bottom of the tower, it is separated, subjected to vacuum distillation and crystallization to obtain the finished product of ethylene sulfate, with a purity of 89.57% and a molar yield of 64.35%.

[0040] Example 3

[0041] The method for continuously preparing ethylene sulfate in this example includes the following steps:

[0042] (1) Preparation of the titanium silicate molecular sieve catalyst: Add 15 Kg of cetyltrimethylammonium bromide and 16.5 Kg of tetraethyl orthosilicate into 300 L of ethanol, stir and disperse evenly, add 50 Kg of Ti-MOR type molecular sieve, stir at room temperature for 3 hours, heat up to 42 - 45 °C, add 6.25 Kg of hexamethyldisilazane and 3 Kg of nanoaluminum trifluoride, stir for 10 hours, separate the solid and liquid, wash the solid with ethanol, and dry it at 120 °C for 6 hours to obtain the modified Ti-MOR type molecular sieve catalyst.

[0043] (2) Add 12 Kg of the modified Ti-MOR type molecular sieve catalyst into a tower-type fixed bed reactor. Prepare sufficient ethylene oxide and get a high-pressure sulfur dioxide gas cylinder ready for use. Set the back pressure valve pressure to 1.8 Mpa. The molar ratio of sulfur dioxide to ethylene oxide is 1.3∶1. Connect the above-mentioned liquid material to a feed pump, mix it through a first mixer and preheat it through a first preheater, and then enter from the bottom of the tower-type fixed bed reactor. The space velocity of the mixed gas is (gas mass standard condition volume flow rate / catalyst bed volume) 800 h -1 and control the reaction temperature at 42 - 45 °C.

[0044] (3) Feed hydrogen peroxide and chloroform through a plunger pump, where the molar ratio of hydrogen peroxide to ethylene oxide is 1.2:1, the volume ratio of hydrogen peroxide to chloroform is 1:5, and the volume space velocity is 5 h -1 (mass flow rate of the mixed liquid / mass of the catalyst bed), the reaction liquid is preheated through a second mixer and a second preheater and then enters from the top of the reactor. The reaction temperature is 42 - 45 °C, the reaction pressure is 1.8 Mpa. After the reaction liquid flows out from the bottom of the tower, it undergoes liquid separation, vacuum distillation, and crystallization to obtain the finished product of vinyl sulfate, with a purity of 96.34% and a molar yield of 78.50%.

[0045] Example 4

[0046] The difference between Example 4 and Example 1 is that the amount of tetraethyl orthosilicate used in the preparation process of the titanium silicalite catalyst is 10 Kg, and the remaining operation steps are the same as those in Example 1. Finally, the purity of the obtained finished product of vinyl sulfate is 97.68%, and the yield is 80.57%.

[0047] Example 5

[0048] The difference between Example 5 and Example 1 is that the amount of tetraethyl orthosilicate used in the preparation process of the titanium silicalite catalyst is 20 Kg, and the remaining operation steps are the same as those in Example 1. Finally, the purity of the obtained finished product of vinyl sulfate is 95.35%, and the yield is 77.36%.

[0049] Example 6

[0050] The difference between Example 6 and Example 1 is that the silane coupling agent used in the preparation process of the titanium silicalite catalyst is trimethylchlorosilane, and the amount used is 5.05 Kg. The remaining operations are the same as those in Example 1. Finally, the purity of the obtained finished product of vinyl sulfate is 98.93%, and the yield is 82.15%.

[0051] Example 7

[0052] The difference between Example 6 and Example 1 is that the silane coupling agent used in the preparation process of the titanium silicalite catalyst is tetramethyldisilazane, and the amount used is 6.19 Kg. The remaining operations are the same as those in Example 1. Finally, the purity of the obtained finished product of vinyl sulfate is 97.38%, and the yield is 80.28%.

[0053] Comparative Example 1

[0054] The difference between Comparative Example 1 and Example 1 is that the catalyst used is a traditional TS-1 titanium silicalite. Without modification operations, directly perform steps (2) and (3), and the remaining operations are the same as those in Example 1. Finally, the purity of the obtained finished product of vinyl sulfate is 92.64%, and the yield is 75.50%.

[0055] Comparative Example 2

[0056] The difference between Comparative Example 2 and Example 1 is that a traditional batch reactor is used, specifically:

[0057] First step: 250 Kg of ethylene oxide is replaced with nitrogen, and 10 Kg of titanium silicalite catalyst is added. The titanium silicalite catalyst is prepared according to the steps of Example 1. The pressure is charged to 2.0 Mpa with a sulfur dioxide high-pressure gas cylinder, the temperature is raised to 45 - 48 °C, stirring is started, and the reaction time is 1.5 hours.

[0058] Second step: After the first-step reaction is completed, 1250 L of chloroform is added to the reactor, and then 482.74 Kg (1.1 eq) of 27.5 wt% hydrogen peroxide is slowly added dropwise. The temperature is controlled at 45 - 48 °C. After the addition is completed, it is kept warm for 1 hour. After the reaction is completed, the ethylene sulfate finished product is obtained through liquid separation, vacuum distillation and crystallization, with a purity of 96.56% and a yield of 78.35%.

[0059] Comparing the comparative example with Comparative Example 1, the catalytic activity and selectivity of the traditional titanium silicalite are relatively poor; comparing the comparative example with Comparative Example 2, compared with the traditional batch method for preparing ethylene sulfate, the continuous technology scheme of the present invention for preparing ethylene sulfate in one step improves the reaction efficiency and production safety, the reaction conditions are simpler, the purity and yield of the prepared ethylene sulfate are higher, and the production cost is reduced.

[0060] In summary, the present invention provides a continuous technology scheme for preparing ethylene sulfate. Using this technology scheme, it has the advantages of high synthesis efficiency, good selectivity, low cost, safe and stable process, and environmental protection, and has the prospect of industrial application.

[0061] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for continuously preparing ethylene sulfate, characterized in that, The method comprises the following steps: (1) Mesoporous templating agent and tetraethyl orthosilicate are added to ethanol and stirred until evenly dispersed. Granular titanium silicate molecular sieve is added, and the mixture is stirred at room temperature for 1 to 3 hours. Then the temperature is raised to 40°C to 60°C, and silane coupling agent and nanoaluminum trifluoride are slowly added. Stir for 6 to 12 hours, separate the solid and liquid, wash with ethanol, and the obtained solid is dried at 100 to 200°C for 3 to 9 hours to obtain a titanium silicate molecular sieve catalyst. The obtained catalyst is loaded into a tower-type fixed-bed reactor; (2) Ethylene oxide and sulfur dioxide are passed through a first mixer and a first preheater and then fed into the tower-type fixed-bed reactor filled with the catalyst from the bottom of the tower to carry out a reaction to obtain a reaction liquid of vinyl sulfite; (3) Hydrogen peroxide and chloroform are passed through a second mixer and a second preheater and then fed into the tower-type reactor filled with the catalyst from the top of the tower to carry out a reaction. The tail gas at the top of the tower is recycled, and the liquid flowing out from the bottom of the tower is a reaction liquid containing ethylene sulfate. After liquid separation, concentration by reduced pressure distillation and freeze crystallization, the solid is collected to obtain an ethylene sulfate product.

2. The continuous preparation method of vinyl sulfate according to claim 1, characterized in that, In the step (1), the mesoporous templating agent is one or more of cetyltrimethylammonium bromide, dodecyltrimethylammonium bromide, Triton X-100, Tween, and polydiallyldimethylammonium chloride.

3. The method for continuously preparing ethylene sulfate according to claim 1, characterized in that, In the step (1), the granular titanium silicate molecular sieve is one or more of TS-1, Ti-MWW, and Ti-MOR.

4. The method for continuously preparing ethylene sulfate according to claim 1, wherein In the step (1), the particle size of the granular titanium silicate molecular sieve is 1 to 5 mm.

5. The method for continuously preparing ethylene sulfate according to claim 1, wherein In the step (1), the silane coupling agent is one or more of hexamethyldisilazane, trimethylchlorosilane, trifluoroethyltriethoxysilane, methoxytrimethylsilane, and tetramethyldisilazane.

6. The method for continuously preparing ethylene sulfate according to claim 1, characterized in that, In the step (1), the molar ratio of tetraethyl orthosilicate, silane coupling agent, nanoaluminum trifluoride to the granular titanium silicate molecular sieve is tetraethyl orthosilicate∶silane coupling agent∶nanoaluminum trifluoride∶granular titanium silicate molecular sieve (calculated as SiO2)=0.05 - 0.13∶0.03 - 0.10∶0.02 - 0.08∶1.

7. The method for continuously preparing ethylene sulfate according to claim 1, wherein In the step (1), the molar ratio of the mesoporous templating agent to the titanium silicate molecular sieve (calculated as SiO2) is 0.02 - 0.07∶1.

8. The method for continuously preparing ethylene sulfate according to claim 1, characterized in that, In the step (2), the molar ratio of sulfur dioxide to ethylene oxide is 1.2 - 1.5∶1, and the space velocity of the mixed gas is 300 - 1400 h -1 .

9. The method for continuously preparing vinyl sulfate according to claim 1, characterized in that, In the step (3), the volume ratio of hydrogen peroxide to chloroform is 1:5 - 10, the molar ratio of hydrogen peroxide to ethylene oxide is 1.1 - 1.5:1, and the hourly space velocity of the mixed liquid is 3 - 12 h -1 .

10. The method for continuously preparing ethylene sulfate according to claim 1, wherein In the steps (2) and (3), the reaction temperature in the tower-type fixed-bed reactor is 30 to 50°C, and the reaction pressure is 0.2 to 2 MPa.

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