Method for separating oil and water in ethylene sulfate synthesis and purification device

Abstract

The invention provides a method for separating oil and water in ethylene sulfate synthesis and a purification device. The method for separating oil and water in the ethylene sulfate synthesis reaction comprises the following steps: filtering a substance obtained after an oxidation reaction is completed so as to remove catalyst particles; standing and separating to obtain a heavy component; adding a demulsifier into the heavy component and mixing to obtain a heavy component mixed solution; and the heavy component mixed solution enters a demulsification membrane separation device at a certain flow rate for separation of a water phase and an ethylene sulfate oil phase. The demulsification membrane separation device is used for separating moisture in the oil phase after the reaction of converting ES into DTD, the physical operation can avoid the influence on purity due to additional addition of chemical reagents, the process is simple, the time is short, and the continuity and automation of oil-water separation in the DTD synthesis reaction can be realized.

Description

Technical Field

[0001] This invention relates to the field of chemical raw material synthesis technology, particularly to the synthesis of vinyl sulfate, and even more particularly to a method for oil-water separation in the synthesis of vinyl sulfate, and a synthesis and purification apparatus for vinyl sulfate. Background Technology

[0002] Numerous studies have confirmed that adding a small amount of vinyl sulfate (DTD) to the electrolyte can significantly improve the performance and cycle life of lithium-ion batteries, thanks to its promotion of the formation of a stable and efficient solid electrolyte interface (SEI film).

[0003] Currently, vinyl sulfate (DTD) is typically produced by oxidizing vinyl sulfite (ES) using hydrogen peroxide as the oxidant and titanium silicate molecular sieve (TS-1) as the catalyst. This synthetic route is mature, environmentally friendly, and has become the mainstream production process. However, due to the unique molecular structure of DTD, it is highly sensitive to moisture. Even trace amounts of water can cause hydrolysis, forming acidic substances. An acidic environment accelerates the decomposition of DTD, resulting in yield loss. Therefore, after the ES to DTD conversion reaction, the organic phase needs to be dehydrated to ≤1000 ppm before subsequent steps. While some reports suggest adding chemical desiccants to remove moisture from the organic phase, specifically by adding a certain amount of desiccant to adsorb moisture and then filtering it out, this process is not feasible. While this approach meets the product's moisture requirements, it has the following drawbacks: 1. The drying and dehydration process requires the addition of chemical reagents, and incomplete filtration may introduce new impurities, affecting product purity; 2. The desiccant adsorption and filtration processes are time-consuming, extending the contact time between DTD and water, which may increase the risk of DTD hydrolysis; 3. The process is relatively complex, which is not conducive to the automation and continuous production of the DTD reaction. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method and purification apparatus for oil-water separation in the synthesis of vinyl sulfate (ES). The method utilizes a demulsification membrane separation device to separate water from the oil phase after the conversion of ES to DTD. This physical operation avoids the need for additional chemical reagents that could affect purity. Furthermore, the process is simple, quick, and enables continuous and automated oil-water separation in the DTD synthesis reaction.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for oil-water separation in the synthesis reaction of vinyl sulfate, wherein the vinyl sulfate is obtained by oxidation of vinyl sulfite under the condition of catalyst particles, and includes the steps of: filtering the substance obtained after the oxidation reaction to remove the catalyst particles; allowing it to stand and separate to obtain a heavy component; adding a demulsifier to the heavy component and mixing to obtain a mixture of heavy components; and introducing the mixture of heavy components into a demulsification membrane separation device at a certain flow rate to separate the aqueous phase and the vinyl sulfate oil phase.

[0006] In the method of this invention, catalyst particles are removed by filtration, and most of the water is removed by static separation to obtain heavy components (mainly composed of reaction products, solvents, and unreacted raw materials). Before entering the demulsification membrane separation device, a demulsifier is added to the heavy components to improve the oil-water separation effect and increase the demulsification efficiency. The heavy component mixture is introduced into the demulsification membrane separation device at a certain flow rate, where the aqueous phase and the vinyl sulfate oil phase are separated by hydrophilic and lipophilic filter elements. This invention uses demulsification membrane separation to replace chemical desiccants to remove water from the organic phase. This physical operation avoids the need for additional chemical reagents that could affect purity. Compared to adsorption dehydration, its shorter processing time reduces the DTD hydrolysis rate and increases the product yield. The introduction of the demulsification membrane separation device enables the oil-water separation step in the DTD synthesis reaction process to be automated and continuous.

[0007] As a technical solution of the present invention, the demulsifying membrane separation device includes a hydrophilic packing filter element and an oleophilic water-blocking filter element, wherein the hydrophilic packing filter element is connected to a first drain port and the oleophilic water-blocking filter element is connected to a second drain port.

[0008] As a technical solution of the present invention, the hydrophilic filler filter element is located in the middle of the demulsification membrane separation device, the oleophilic water-blocking filter element surrounds the hydrophilic filler filter element, the first drain port is located at the top of the demulsification membrane separation device, and the second drain port is located at the bottom of the demulsification membrane separation device.

[0009] As one technical solution of the present invention, the catalyst particles are titanium-silicon molecular sieves, the oxidant used in the oxidation reaction is hydrogen peroxide, and the solvent used in the oxidation reaction is selected from dimethyl carbonate, dichloromethane, acetone or dichloroethane.

[0010] As a technical solution of the present invention, in the heavy components, the content of vinyl sulfite is 0.1~5.0 wt.%, the content of vinyl sulfate is 5~40 wt.%, and the moisture content is 1~3 wt.%.

[0011] As a technical solution of the present invention, a pH adjuster is added to the heavy components to adjust to neutral before the demulsifier is added. The pH adjuster is selected from sodium carbonate, sodium bicarbonate or sodium hydroxide.

[0012] As a technical solution of the present invention, the demulsifier is selected from sodium dodecyl sulfate, sodium dodecylbenzene sulfonate or dodecyl polyoxyethylene ether, and the demulsifier is 0.5~2.0 wt.% of the heavy components.

[0013] As a technical solution of the present invention, the inlet temperature of the demulsification membrane separation device is controlled at 5~35°C.

[0014] As a technical solution of the present invention, the certain flow velocity is 5~10m. 3 / h.

[0015] A second aspect of the present invention provides an apparatus for the synthesis and purification of vinyl sulfate, comprising a synthesis reactor, a filter, a separation tank, a mixing tank, and a demulsification membrane separation device connected in sequence. The synthesis reactor is used for the oxidation reaction of vinyl sulfite under catalyst particle conditions. The filter is used to filter out the catalyst particles. The separation tank is used to separate the heavy components in the substance obtained after the oxidation reaction. The mixing tank is used to mix the heavy components and a demulsifier to obtain a heavy component mixture. The demulsification membrane separation device is used to separate the aqueous phase and the vinyl sulfate oil phase in the heavy component mixture. A pipeline and a valve pump for controlling the flow rate in the pipeline are provided between the mixing tank and the demulsification membrane separation device.

[0016] The apparatus of the present invention comprises a synthesis reactor, a filter, a separation tank, a mixing tank, and a demulsification membrane separation device connected in sequence. This apparatus can realize the automated and continuous operation of the synthesis and purification of vinyl sulfate. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the apparatus for synthesizing and purifying vinyl sulfate according to the present invention. Detailed Implementation

[0018] like Figure 1 As shown, the synthesis and purification apparatus for vinyl sulfate of the present invention includes a synthesis reactor 10, a filter 20, a separation tank 30, a mixing tank 40, and a demulsification membrane separation device 50 connected in sequence.

[0019] The synthesis reactor 10 is used for the oxidation reaction of vinyl sulfite under catalyst particle conditions. It includes an inner cavity 11, a solid feed inlet 13, a liquid feed inlet 15, and a discharge outlet 17. The solid feed inlet 13, liquid feed inlet 15, and discharge outlet 17 are all connected to the inner cavity 11. Catalyst particles are fed into the inner cavity 11 through the solid feed inlet 13. Vinyl sulfite, oxidant, and solvent used in the oxidation reaction are fed into the inner cavity 11 through the liquid feed inlet 15. The discharge outlet 17 is connected to a filter 20 via a pipeline. Vinyl sulfite undergoes an oxidation reaction in the synthesis reactor 10 under catalyst particle conditions. After the oxidation reaction is complete, the resulting material passes through the filter 20, retaining the catalyst particles in the filter 20. The liquid component is discharged into a separation tank 30. Catalyst particles are discharged from the filter 20 only when a certain amount remains to avoid affecting the filtration effect. In the separation tank 30, the heavy components of the resulting material after the oxidation reaction are separated and enter a mixing tank 40. The inlets of filter 20 and separator 30 can be located at the top and the outlets at the bottom, or other locations. Mixing vessel 40 includes a stirrer 41 and a feed port 43 for adding pH adjusters and demulsifiers. The heavy components, pH adjuster, and demulsifier are mixed evenly in mixing vessel 40 before entering demulsification membrane separation device 50. A pipeline and a valve / pump for controlling the flow rate are installed between mixing vessel 40 and demulsification membrane separation device 50. Alternatively, pipelines can be used to connect synthesis reactor 10, filter 20, separator 30, and mixing vessel 40. Demulsification membrane separation device 50 includes an inlet 51, a hydrophilic packing filter element 53, and an oleophilic water-blocking filter element 55. Inlet 51 connects to the oleophilic water-blocking filter element 55, the hydrophilic packing filter element 53 connects to the first outlet 59, and the oleophilic water-blocking filter element 55 connects to the second outlet 57. A hydrophilic filter cartridge 53 is located in the middle of the demulsification membrane separation device 50, and an oleophilic water-blocking filter cartridge 55 surrounds the hydrophilic filter cartridge 53. Furthermore, a first drain port 59 is located at the top of the demulsification membrane separation device 50, and a second drain port 57 is located at the bottom of the device. The heavy components, pH adjuster, and demulsifier are mixed evenly in the mixing vessel 40 before entering the demulsification membrane separation device 50. Water droplets dispersed in the heavy components are captured by the hydrophilic skeleton in the hydrophilic filter cartridge 53. During continuous liquid intake, these droplets gradually aggregate into larger droplets, eventually detaching from the skeleton and rising to the top of the demulsification membrane separation device 50, where they are discharged through the first drain port 59. At this point, the oil phase containing DTD is discharged through the second drain port 57, which is connected to the oleophilic water-blocking filter cartridge 55, for subsequent operations.

[0020] The vinyl sulfate of the present invention can be obtained by oxidizing vinyl sulfite under catalytic particle conditions. The catalyst particles are titanium silicate molecular sieves, the oxidant used in the oxidation reaction is hydrogen peroxide, and the solvent used in the oxidation reaction is selected from dimethyl carbonate, dichloromethane, acetone, or dichloroethane.

[0021] After the oxidation reaction is completed, the obtained substance can be separated into oil and water. The oil-water separation method may include the following steps: filtering the substance obtained after the oxidation reaction to remove catalyst particles; allowing it to stand and separate to obtain heavy components; adding a demulsifier to the heavy components and mixing to obtain a heavy component mixture; and introducing the heavy component mixture into a demulsification membrane separation device at a certain flow rate to separate the aqueous phase and the vinyl sulfate oil phase.

[0022] Preferably, in the heavy components, the content of vinyl sulfite is 0.1~5.0 wt.%, the content of vinyl sulfate is 5~40 wt.%, and the water content is 1~3 wt.%, to avoid excessive water content in the heavy components, which could lead to hydrolysis in the demulsification membrane separation device. A pH adjuster is added to the heavy components to adjust the pH to neutral before adding the demulsifier. Adding a pH adjuster to neutrality avoids acidity, which could affect the service life of the demulsification membrane separation device. The pH adjuster is selected from sodium carbonate, sodium bicarbonate, or sodium hydroxide. An alkaline adjuster is used to adjust the pH to neutral to avoid the impact of acidic substances on the separation life of the demulsification membrane separation device. The demulsifier is selected from sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, or dodecyl polyoxyethylene ether, and the demulsifier content is 0.5~2.0 wt.% of the heavy components. This type of demulsifier accelerates oil-water separation and improves demulsification efficiency. The inlet temperature of the demulsification membrane separation device is controlled at 5~35°C. Low-temperature demulsification membrane separation is used to avoid excessive temperature, which could accelerate the hydrolysis of vinyl sulfate. The flow rate of the heavy component mixture entering the demulsification membrane separation device is 5~10m. 3 A high flow rate ( / h) can shorten the contact time between vinyl sulfate and water, but the flow rate should not be too low to avoid incomplete water separation. The demulsification membrane separation device includes a hydrophilic packing filter element and an oleophilic water-blocking filter element. The hydrophilic packing filter element is connected to the first drain port, and the oleophilic water-blocking filter element is connected to the second drain port. The hydrophilic packing filter element is located in the middle of the demulsification membrane separation device, and the oleophilic water-blocking filter element surrounds the hydrophilic packing filter element. The first drain port is located at the top of the demulsification membrane separation device, and the second drain port is located at the bottom of the device. The heavy component mixture enters the demulsification membrane separation device. The dispersed water droplets in the heavy components are captured by the hydrophilic skeleton in the hydrophilic packing filter element. During the continuous liquid feeding process, they gradually aggregate into large water droplets. Finally, the water droplets detach from the skeleton, gather, and rise to the top of the demulsification membrane separation device, and are discharged through the first drain port. At this time, the oil phase containing DTD is discharged through the second drain port connected to the oleophilic water-blocking filter element for subsequent operations.

[0023] To better illustrate the purpose, technical solution, and beneficial effects of this invention, the invention will be further described below with reference to specific embodiments. It should be noted that the methods described below are further explanations of this invention and should not be construed as limiting it.

[0024] Example 1 This embodiment describes a method for oil-water separation in the synthesis reaction of vinyl sulfate. The reaction raw materials for this synthesis reaction are vinyl sulfite, dichloromethane solution, TS-1 catalyst, and hydrogen peroxide solution. The reaction is stopped when the ES content in the solution is lower than 0.5 wt.%.

[0025] The synthesized product was filtered to remove TS-1 catalyst particles, and then allowed to stand to separate the heavy components. The heavy components were added to a stirred tank; at this point, the water content of the heavy components was 2 wt.%, and the inlet temperature was 20°C. Sodium bicarbonate was added to the heavy components to adjust the pH to approximately 7, and then sodium dodecylbenzenesulfonate (1.0 wt.% of the heavy components) was added and mixed to obtain a mixture of the heavy components. The mixture was then stirred at a flow rate of 8 m / s. 3 The heavy component mixture was fed into a demulsifying membrane separator at a temperature of 20°C per hour for separation. The obtained oil phase was analyzed and found to contain 50 ppm water, with a DTD yield of 83%.

[0026] Example 2 This embodiment describes a method for oil-water separation in the synthesis reaction of vinyl sulfate. The reaction raw materials for this synthesis reaction are vinyl sulfite, dichloromethane solution, TS-1 catalyst, and hydrogen peroxide solution. The reaction is stopped when the ES content in the solution is lower than 0.5 wt.%.

[0027] The synthesized product was filtered to remove TS-1 catalyst particles, and then allowed to stand to separate the heavy components. The heavy components were added to a stirred tank; at this point, the water content of the heavy components was 2 wt.%, and the inlet temperature was 20°C. Sodium bicarbonate was added to the heavy components to adjust the pH to approximately 7, and then sodium dodecylbenzenesulfonate (1.0 wt.% of the heavy components) was added and mixed to obtain a mixture of the heavy components. The mixture was then stirred at a flow rate of 10 m / s. 3 The heavy component mixture was fed into a demulsification membrane separator at a temperature of 20°C per hour for separation. The obtained oil phase was analyzed and found to contain 54 ppm of water, with a DTD yield of 80%.

[0028] Example 3 This embodiment describes a method for oil-water separation in the synthesis reaction of vinyl sulfate. The reaction raw materials for this synthesis reaction are vinyl sulfite, dichloromethane solution, TS-1 catalyst, and hydrogen peroxide solution. The reaction is stopped when the ES content in the solution is lower than 0.5 wt.%.

[0029] The synthesized product was filtered to remove TS-1 catalyst particles, and then allowed to stand to separate the heavy components. The heavy components, with a moisture content of 2 wt.% and an inlet temperature of 20°C, were added to a stirred tank. Sodium dodecyl sulfate (1.5 wt.% of the heavy components) was added and mixed to obtain a mixture of the heavy components. The mixture was then stirred at a flow rate of 10 m / s. 3 The heavy component mixture is fed into a demulsification membrane separator at a temperature of 20°C per hour for separation. The obtained oil phase is analyzed and found to contain 52 ppm of water, with a DTD yield of 81%.

[0030] Example 4 This embodiment describes a method for oil-water separation in the synthesis reaction of vinyl sulfate. The reaction raw materials for this synthesis reaction are vinyl sulfite, dimethyl carbonate solution, TS-1 catalyst, and hydrogen peroxide solution. The reaction is stopped when the ES content in the solution is lower than 0.5 wt.%.

[0031] The synthesized product was filtered to remove TS-1 catalyst particles, and then allowed to stand to separate the heavy components. The heavy components were added to a stirred tank; at this point, the water content of the heavy components was 2 wt.%, and the inlet temperature was 20°C. Sodium bicarbonate was added to the heavy components to adjust the pH to approximately 7, and then sodium dodecylbenzenesulfonate (1.0 wt.% of the heavy components) was added and mixed to obtain a mixture of the heavy components. The mixture was then stirred at a flow rate of 8 m / s. 3 The heavy component mixture was fed into a demulsification membrane separator at a temperature of 20°C per hour for separation. The obtained oil phase was analyzed and found to contain 54 ppm of water, with a DTD yield of 80%.

[0032] Comparative Example 1 This comparative example illustrates a method for oil-water separation in the synthesis of vinyl sulfate. The reactants for this synthesis reaction are vinyl sulfite, dichloromethane solution, TS-1 catalyst, and hydrogen peroxide solution. The reaction is stopped when the ES content in the solution is below 0.5 wt.%.

[0033] The synthesized material was filtered to remove TS-1 catalyst particles, and then allowed to stand to separate the heavy components. The heavy components were added to a stirred tank; at this point, the moisture content of the heavy components was 2 wt.%, and the inlet temperature was 20°C. Anhydrous magnesium sulfate (1.0 wt.% of the heavy components) was added to the stirred tank, and the mixture was stirred for 30 minutes to remove water. After dehydration, the mixture was filtered, and the moisture content was measured to be 700 ppm, with a DTD yield of 75%.

[0034] Comparative Example 2 This comparative example illustrates a method for oil-water separation in the synthesis of vinyl sulfate. The reactants for this synthesis reaction are vinyl sulfite, dichloromethane solution, TS-1 catalyst, and hydrogen peroxide solution. The reaction is stopped when the ES content in the solution is below 0.5 wt.%.

[0035] The synthesized product was filtered to remove TS-1 catalyst particles, and then allowed to stand to separate the heavy components. The heavy components, with a water content of 2 wt.% and an inlet temperature of 20°C, were added to a stirred tank. Sodium bicarbonate was added to adjust the pH to approximately 7, resulting in a mixture of the heavy components. The mixture was then flowed at a flow rate of 10 m / s. 3 The heavy component mixture is fed into a demulsification membrane separator at a temperature of 20°C per hour for separation. The obtained oil phase is analyzed and found to contain 200 ppm of water, with a DTD yield of 80%.

[0036] Comparative Example 3 This comparative example illustrates a method for oil-water separation in the synthesis of vinyl sulfate. The reactants for this synthesis reaction are vinyl sulfite, dichloromethane solution, TS-1 catalyst, and hydrogen peroxide solution. The reaction is stopped when the ES content in the solution is below 0.5 wt.%.

[0037] The synthesized product was filtered to remove TS-1 catalyst particles, and then allowed to stand to separate the heavy components. The heavy components were added to a stirred tank; at this point, the water content of the heavy components was 2 wt.%, and the inlet temperature was 20°C. Sodium bicarbonate was added to the heavy components to adjust the pH to approximately 7, resulting in a mixture of the heavy components. The mixture was then stirred at a flow rate of 8 m / s. 3 The mixture of heavy components was fed into a demulsifying membrane separator at a temperature of 20°C per hour for separation. The obtained oil phase was analyzed and found to contain 150 ppm of water, with a DTD yield of 78%.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for oil-water separation in the synthesis reaction of ethylene sulfate, characterized in that, The ethylene sulfate is obtained by oxidizing ethylene sulfite under catalyst particle conditions, including the step of filtering the obtained substance after the oxidation reaction to remove the catalyst particles. After standing and separation, heavy components are obtained; a demulsifier is added to the heavy components and mixed to obtain a heavy component mixture; the heavy component mixture is fed into a demulsification membrane separation device at a certain flow rate to separate the aqueous phase and the vinyl sulfate oil phase.

2. The method for oil-water separation in the synthesis reaction of ethylene sulfate according to claim 1, characterized in that, The demulsifying membrane separation device includes a hydrophilic packing filter element and an oleophilic water-blocking filter element. The hydrophilic packing filter element is connected to a first drain port, and the oleophilic water-blocking filter element is connected to a second drain port.

3. The method for oil-water separation in the synthesis reaction of ethylene sulfate according to claim 2, characterized in that, The hydrophilic filler filter element is located in the middle of the demulsification membrane separation device, the oleophilic water-blocking filter element surrounds the hydrophilic filler filter element, the first drain port is located at the top of the demulsification membrane separation device, and the second drain port is located at the bottom of the demulsification membrane separation device.

4. The method for oil-water separation in the synthesis reaction of ethylene sulfate according to claim 1, characterized in that, The catalyst particles are titanium-silicon molecular sieves, the oxidant used in the oxidation reaction is hydrogen peroxide, and the solvent used in the oxidation reaction is selected from dimethyl carbonate, dichloromethane, acetone, or dichloroethane.

5. The method for oil-water separation in the synthesis reaction of ethylene sulfate according to claim 1, characterized in that, In the aforementioned heavy components, the content of vinyl sulfite is 0.1~5.0 wt.%, the content of vinyl sulfate is 5~40 wt.%, and the moisture content is 1~3 wt.%.

6. The method for oil-water separation in the synthesis reaction of ethylene sulfate according to claim 1, characterized in that, A pH adjuster is added to the heavy components to adjust them to neutral before adding the demulsifier. The pH adjuster is selected from sodium carbonate, sodium bicarbonate, or sodium hydroxide.

7. The method for oil-water separation in the synthesis reaction of ethylene sulfate according to claim 1, characterized in that, The demulsifier is selected from sodium dodecyl sulfate, sodium dodecylbenzene sulfonate or dodecyl polyoxyethylene ether, and the demulsifier is 0.5~2.0 wt.% of the heavy components.

8. The method for oil-water separation in the synthesis reaction of ethylene sulfate according to claim 1, characterized in that, The inlet temperature of the demulsifying membrane separation device is controlled at 5~35°C.

9. The method for oil-water separation in the synthesis reaction of ethylene sulfate according to claim 1, characterized in that, The specified flow velocity is 5~10m. 3 / h.

10. An apparatus for the synthesis and purification of vinyl sulfate, characterized in that, The apparatus comprises a synthesis reactor, a filter, a separation tank, a mixing tank, and a demulsification membrane separation device connected in sequence. The synthesis reactor is used for the oxidation reaction of vinyl sulfite under catalyst particle conditions. The filter is used to filter out the catalyst particles. The separation tank is used to separate the heavy components from the substance obtained after the oxidation reaction. The mixing tank is used to mix the heavy components and the demulsifier to obtain a heavy component mixture. The demulsification membrane separation device is used to separate the aqueous phase and the vinyl sulfite oil phase in the heavy component mixture. A pipeline and a valve pump for controlling the flow rate in the pipeline are provided between the mixing tank and the demulsification membrane separation device.

Images