A method for preparing dimethyl sulfoxide

Abstract

This invention discloses a method for preparing dimethyl sulfoxide, relating to the field of electrochemical technology. The method for preparing dimethyl sulfoxide includes the following steps: passing gaseous dimethyl sulfide and water vapor into the anode of an electrochemical reaction device, passing water into the cathode of the electrochemical reaction device, and applying a DC voltage between the anode and cathode to carry out an electrochemical reaction to obtain a product containing dimethyl sulfoxide; wherein, the anode includes a composite matrix and a perfluorosulfonic acid ionomer loaded on the surface of the composite matrix; the composite matrix includes a first substrate and an anti-corrosion coating disposed on the surface of the first substrate, the anti-corrosion coating being made of at least one of ruthenium oxide, iridium oxide, antimony-doped tin oxide, tantalum oxide, and lead oxide, which solves the problems of high energy consumption, low product yield and selectivity in the preparation of dimethyl sulfoxide by liquid-phase electrochemical oxidation method in the prior art.

Description

Technical Field

[0001] This invention relates to the field of electrochemical technology, and more specifically, to a method for preparing dimethyl sulfoxide. Background Technology

[0002] Dimethyl sulfoxide (DMSO), as an important organic solvent, is widely used in many industrial fields. Its preparation methods mainly include nitrogen dioxide oxidation, hydrogen peroxide oxidation, and liquid-phase electrochemical oxidation. While nitrogen dioxide oxidation dominates industrial production, its accompanying problems cannot be ignored. First, the treatment of nitrogen oxide emissions not only increases production costs but also poses a challenge to environmental protection. Second, equipment suffers corrosion during long-term operation, reducing operating efficiency and increasing maintenance costs. Although hydrogen peroxide oxidation avoids the use of nitrogen oxides, its oxidant is expensive, and the product is prone to over-oxidation, leading to reduced selectivity, which limits its commercial viability. Liquid-phase electrochemical oxidation attempts to solve these problems, using water as an oxygen source, but faces several major difficulties in practical application. First, the high internal resistance of the electrolyte significantly increases energy consumption during electrolysis. Second, the complex electrolyte composition (such as organic solvents and electrolytes) makes product separation and purification processes cumbersome and expensive, thus affecting the purity of DMSO and overall production efficiency. These factors severely restrict the industrial-scale application of electrochemical oxidation in the production of dimethyl sulfoxide.

[0003] In existing liquid-phase electrochemical oxidation technologies, current densities are generally low, directly leading to slow production rates and insufficient capacity. Furthermore, the need to add additional organic solvents and electrolytes to the electrolyte not only increases production costs but also complicates product purification, reducing the purity of the final product, DMSO. More critically, these traditional methods often consume significant amounts of energy and generate substantial carbon emissions during operation. Therefore, how to further improve the yield and selectivity of dimethyl sulfoxide while reducing energy consumption is a pressing technical problem to be solved in this field. Summary of the Invention

[0004] The main objective of this invention is to provide a method for preparing dimethyl sulfoxide, thereby solving the problems of high energy consumption, low product yield and selectivity in the preparation of dimethyl sulfoxide by liquid-phase electrochemical oxidation in the prior art.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for preparing dimethyl sulfoxide is provided, comprising the following steps:

[0006] Gas-phase dimethyl sulfide and water vapor are introduced into the anode of an electrochemical reactor, water is introduced into the cathode of the electrochemical reactor, and a DC voltage is applied between the anode and the cathode to carry out an electrochemical reaction, thereby obtaining a product containing dimethyl sulfoxide.

[0007] The anode includes a composite matrix and a perfluorosulfonic acid ionomer loaded on the surface of the composite matrix; the composite matrix includes a first substrate and an anti-corrosion coating disposed on the surface of the first substrate, wherein the material of the anti-corrosion coating includes at least one of ruthenium oxide, iridium oxide, antimony-doped tin oxide, tantalum oxide, and lead oxide.

[0008] Furthermore, the material of the first substrate includes carbon fiber and / or titanium; and / or,

[0009] The loading of perfluorosulfonic acid ionomer on the composite matrix was 0.1 mg / cm³. 2 ~5mg / cm 2 ;

[0010] The anti-corrosion coating was applied at a rate of 0.1 mg / cm² on the first substrate. 2 ~10mg / cm 2 .

[0011] Furthermore, the cathode includes a second substrate and a platinum catalyst supported on the second substrate;

[0012] The platinum catalyst comprises metallic platinum particles with a particle size of 1 nm to 10 μm.

[0013] And / or, the material of the second substrate includes carbon fiber and / or titanium.

[0014] And / or, the platinum loading in the platinum catalyst on the second substrate is 0.01 mg / cm³. 2 ~5mg / cm 2 ;

[0015] And / or, the material of the anti-corrosion coating is selected from antimony-doped tin oxide, wherein the antimony doping mass content is 1% to 20%, preferably 8% to 12%.

[0016] Furthermore, the volumetric flow rate ratio of gaseous dimethyl sulfide to water vapor is (0.1~10):1.

[0017] Furthermore, the volumetric flow rate ratio of gaseous dimethyl sulfide to water is (0.5~2):2.

[0018] Furthermore, the volumetric flow rate of the gaseous dimethyl sulfide is 0.01 mL / min to 1000 mL / min; and / or,

[0019] The volumetric flow rate of water vapor is 0.01 mL / min to 1000 mL / min; and / or,

[0020] The volumetric flow rate of water is 1 mL / min to 1000 mL / min.

[0021] Furthermore, when gaseous dimethyl sulfide and water vapor are introduced into the anode of the electrochemical reaction device, the process further includes: introducing nitrogen gas into the anode of the electrochemical reaction device, wherein the flow rate ratio of gaseous dimethyl sulfide to nitrogen gas is (0.5~2):10.

[0022] Furthermore, the volumetric flow rate of nitrogen gas is 1 mL / min to 1000 mL / min.

[0023] Furthermore, the electrochemical reaction temperature is 40℃~120℃; and / or,

[0024] The voltage applied between the anode and cathode is 1V~10V; and / or,

[0025] The current density of the electrochemical reaction is 10 mA / cm². 2 ~1000mA / cm 2 .

[0026] Furthermore, the electrochemical reaction device includes a power source, an anode, a cathode, a proton exchange membrane, an anode chamber, and a cathode chamber; the positive terminal of the power source is connected to the anode, the negative terminal of the power source is connected to the cathode, the anode is located in the anode chamber, the cathode is located in the cathode chamber, and the proton exchange membrane is located between the anode and the cathode, wherein the material of the proton exchange membrane includes perfluorosulfonic acid.

[0027] The present invention utilizes gaseous dimethyl sulfide (DMS) and water vapor as raw materials to oxidize DMS within an electrochemical reactor with a specifically structured anode by applying a DC voltage, thereby efficiently producing DMSO. Compared to traditional liquid-phase electrochemical synthesis or nitrogen dioxide oxidation methods, this invention directly introduces gaseous dimethyl sulfide and water vapor into the anode of the electrochemical reactor, avoiding liquid-phase reaction control and byproduct generation. This not only helps improve the efficiency and selectivity of the main reaction but also simplifies product separation steps, reduces production costs and environmental impact, and has broad application prospects and market potential. Attached Figure Description

[0028] Figure 1 This is a graph showing the change of current density over time during the electrochemical reaction process in Embodiment 1 of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] As described in the background section of this invention, the existing liquid-phase electrochemical oxidation method for preparing dimethyl sulfoxide suffers from high energy consumption, low product yield, and low selectivity. To address these issues, in a typical embodiment of this invention, a method for preparing dimethyl sulfoxide is provided. This method involves introducing gaseous dimethyl sulfide and water vapor into the anode of an electrochemical reactor, introducing water into the cathode of the same reactor, and applying a DC voltage between the anode and cathode to perform an electrochemical reaction, thereby obtaining a product containing dimethyl sulfoxide. The anode comprises a composite matrix and a perfluorosulfonic acid ionomer supported on the surface of the composite matrix. The composite matrix comprises a first substrate and an anti-corrosion coating disposed on the surface of the first substrate. The anti-corrosion coating is made of at least one of ruthenium oxide, iridium oxide, antimony-doped tin oxide, tantalum oxide, and lead oxide.

[0031] The preparation of dimethyl sulfoxide (DMSO) in this invention mainly involves two half-reactions, occurring at the anode and cathode respectively. At the anode, dimethyl sulfide (DMS) undergoes electrochemical oxidation, losing electrons to generate dimethyl sulfoxide (DMSO). Simultaneously, water molecules donate oxygen atoms to participate in the oxidation process. The specific reactions are as follows: (g) + H2O (g) → (l) + 2H + +2e - Hydrogen ions migrate through the proton exchange membrane to the anode and undergo the following reaction at the cathode: 2H+ + +2e - →H2(g). The overall reaction for the electrochemical preparation of DMSO is: (g) + H2O (g) → (l) + H2(g).

[0032] This invention utilizes a gas-phase electrochemical method to oxidize gaseous dimethyl sulfide to dimethyl sulfoxide at the anode, while simultaneously generating hydrogen gas at the cathode through water electrolysis. This achieves highly efficient synthesis of DMSO, and the entire process is electrically driven, eliminating the need for traditional chemical oxidants. This avoids the environmental pollution problems caused by oxidant treatment and byproducts, while also simplifying the production process, reducing energy consumption and production costs, and improving the selectivity and purity of the product.

[0033] It should be noted that the water flow into the cathode can carry the DMSO generated in the reaction out of the electrochemical reactor, preventing DMSO from accumulating inside the reactor. This helps maintain the material balance inside the reactor and prevents the products from inhibiting the main reaction.

[0034] The anode of the electrochemical reaction device includes a composite matrix and an ionomer loaded on the surface of the composite matrix. The composite matrix includes a first substrate and an anti-corrosion coating disposed on the surface of the first substrate. The first substrate is made of carbon fiber and / or titanium, the anti-corrosion coating is made of at least one of ruthenium oxide, iridium oxide, antimony-doped tin oxide, tantalum oxide, and lead oxide, and the ionomer includes a perfluorosulfonic acid (Nafion) ionomer. The composite matrix provides the electrode material for the electrochemical reaction, the anti-corrosion coating protects the electrode from corrosion, and the perfluorosulfonic acid ionomer promotes proton transport and improves the efficiency of the electrochemical reaction. This invention, by controlling the specific structure and material of the anode, helps to promote the efficient synthesis of dimethyl sulfoxide while reducing energy consumption and by-product generation.

[0035] This invention utilizes gaseous dimethyl sulfide (DMS) and water vapor as raw materials. DMS is oxidized by applying a DC voltage within an electrochemical reactor with a specifically structured anode, thereby efficiently producing DMSO. Compared to traditional liquid-phase electrochemical synthesis or nitrogen dioxide oxidation methods, this invention directly introduces gaseous dimethyl sulfide and water vapor into the anode region of the electrochemical reactor, avoiding liquid-phase reaction control and byproduct generation, thus improving the efficiency and selectivity of the main reaction. Inside the electrochemical reactor, a DC voltage is applied between the anode and cathode to induce the oxidation of DMS, while a water reduction reaction occurs simultaneously at the cathode. This electrically driven reaction process eliminates the need for additional chemical oxidants such as nitrogen dioxide, reducing the use and treatment of hazardous substances and enhancing production safety and environmental friendliness. Furthermore, the electrochemical reaction of this invention is carried out in the gas phase under conditions free of electrolytes and organic solvents, eliminating the need to separate the DMSO product from the solvent, simplifying post-processing and reducing subsequent purification costs.

[0036] It should be noted that the water flow through the cathode carries the DMSO generated in the reaction out of the electrochemical reactor. The carried-out DMSO can then enter the subsequent separation unit for purification using vacuum distillation. Vacuum distillation is a distillation process conducted under sub-atmospheric pressure, which lowers the boiling point of DMSO, reduces potential side reactions during distillation, and improves product purity and recovery efficiency. Simultaneously, vacuum distillation saves energy, lowers operating temperature, reduces the heat load on the equipment, and extends its service life.

[0037] When the anti-corrosion coating material is selected from antimony-doped tin oxide, the antimony doping mass content is 1%~20%, preferably 8%~12%.

[0038] This invention does not limit the loading amount of perfluorosulfonic acid ionomer on the composite matrix or the coating amount of the anti-corrosion coating on the first substrate; the loading amount and coating amount can be determined according to actual needs. For example, in some embodiments, the loading amount of perfluorosulfonic acid ionomer on the composite matrix is ​​0.1 mg / cm³. 2 ~5mg / cm 2 Specifically, the loading amount of ionomer on the composite matrix can be 0.1 mg / cm³. 2 0.2 mg / cm 2 0.5 mg / cm 2 0.8 mg / cm 2 1mg / cm 2 1.2 mg / cm 2 1.5 mg / cm 2 2mg / cm 2 2.5 mg / cm 2 3mg / cm 2 3.5 mg / cm 2 4mg / cm 2 4.5 mg / cm 2 5mg / cm 2 or a range consisting of any two of them. The coating amount of the anti-corrosion coating on the first substrate is 0.1 mg / cm³. 2 ~10mg / cm 2 .

[0039] In some embodiments, the cathode includes a second substrate and a platinum catalyst supported on the second substrate, the platinum catalyst comprising particles with a particle size of 1 nm to 10 nm. The platinum catalyst comprises m-sized platinum particles, and the second substrate is made of carbon fiber and / or titanium. The platinum loading on the second substrate is 0.01 mg / cm³. 2 ~5mg / cm 2 The second substrate, serving as a support material for the cathode, helps to stabilize the reaction. By controlling the inclusion of a platinum catalyst in the cathode, which provides the catalytic activity required for the reduction reaction and promotes hydrogen generation, the efficiency and selectivity of the electrochemical reaction are improved. Specifically, the platinum loading on the second substrate in the platinum catalyst can be 0.01 mg / cm³. 2 0.05 mg / cm 2 0.1 mg / cm 2 0.2 mg / cm 2 0.5 mg / cm 2 1mg / cm 2 2mg / cm 2 3mg / cm 2 4mg / cm 2 5mg / cm2 or a range consisting of any two of them.

[0040] This invention does not limit the specific types of the first substrate and the second substrate, as long as they meet the above-mentioned material requirements. For example, the first substrate and the second substrate can be independently selected from carbon fiber paper, carbon fiber cloth, carbon fiber felt, titanium mesh, foamed titanium, titanium fiber felt, or powder sintered porous titanium.

[0041] In some embodiments, the flow rate ratio of gaseous dimethyl sulfide to water vapor is (0.1~10):1. By controlling the flow rate ratio of gaseous dimethyl sulfide to water vapor, sufficient contact and reaction between the gaseous dimethyl sulfide and water vapor can be promoted, which can promote the formation of the target product, improve the selectivity and efficiency of the reaction, especially enhance the Faradaic efficiency of dimethyl sulfoxide, while reducing the formation of by-products and helping to further improve the purity of the product. Specifically, the flow rate ratio of gaseous dimethyl sulfide to water vapor can be a range of 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or any combination thereof.

[0042] In some embodiments, the flow rate ratio of gaseous dimethyl sulfide to water is (0.5~2):2, for example, 0.5:2, 0.6:2, 0.7:2, 0.8:2, 0.9:2, 1:2, 1.2:2, 1.4:2, 1.6:2, 1.8:2, 2:2 or any combination thereof.

[0043] This invention does not limit the specific values ​​of the flow rates of gaseous dimethyl sulfide, water vapor, and water, as long as the above requirements are met. For example, in some embodiments, the volumetric flow rate of gaseous dimethyl sulfide is 0.01 mL / min to 1000 mL / min; and / or, the volumetric flow rate of water vapor is 0.01 mL / min to 1000 mL / min; and / or, the volumetric flow rate of water is 1 mL / min to 1000 mL / min. Specifically, the flow rate of gaseous dimethyl sulfide can be a range of 0.01 mL / min, 1 mL / min, 5 mL / min, 10 mL / min, 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 300 mL / min, 400 mL / min, 500 mL / min, 600 mL / min, 700 mL / min, 800 mL / min, 900 mL / min, 1000 mL / min, or any combination thereof. The water vapor flow rate can be within the range of 0.01 mL / min, 1 mL / min, 5 mL / min, 10 mL / min, 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 300 mL / min, 400 mL / min, 500 mL / min, 600 mL / min, 700 mL / min, 800 mL / min, 900 mL / min, 1000 mL / min, or any combination thereof. The water flow rate can be within the range of 1 mL / min, 5 mL / min, 10 mL / min, 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 300 mL / min, 400 mL / min, 500 mL / min, 600 mL / min, 700 mL / min, 800 mL / min, 900 mL / min, 1000 mL / min, or any combination thereof.

[0044] In some embodiments, when gaseous dimethyl sulfide and water vapor are introduced into the anode of the electrochemical reactor, the process further includes introducing nitrogen gas into the anode of the electrochemical reactor, wherein the flow rate ratio of gaseous dimethyl sulfide to nitrogen gas is (0.5~2):10. Introducing nitrogen gas as a carrier gas facilitates the transport of reaction materials, promotes the uniform distribution of gaseous dimethyl sulfide and water vapor on the anode surface, avoids side reactions caused by excessively high local concentrations, and further improves the efficiency and selectivity of the electrochemical reaction. Specifically, the flow rate ratio of gaseous dimethyl sulfide to nitrogen gas can be within the range of 0.5:10, 0.6:10, 0.7:10, 0.8:10, 0.9:10, 1:10, 1.2:10, 1.4:10, 1.6:10, 1.8:10, 2:10, or any combination thereof.

[0045] The present invention does not limit the specific value of the nitrogen flow rate, as long as the above requirements are met. For example, in some embodiments, the volumetric flow rate of nitrogen is 1 mL / min to 1000 mL / min, such as 1 mL / min, 5 mL / min, 10 mL / min, 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 300 mL / min, 400 mL / min, 500 mL / min, 600 mL / min, 700 mL / min, 800 mL / min, 900 mL / min, 1000 mL / min or any combination thereof.

[0046] This invention does not limit the specific conditions of the electrochemical reaction, as long as the above-mentioned current density requirement is met. For example, in some embodiments, the temperature of the electrochemical reaction is 40°C to 120°C; and / or, the voltage applied between the anode and cathode is 1V to 10V. By controlling the temperature and voltage range of the electrochemical reaction, it is helpful to promote the formation of the target product. Specifically, the temperature of the electrochemical reaction can be a range of 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, or any combination thereof. The voltage applied between the anode and cathode can be a range of 1V, 2V, 3V, 4V, 5V, 6V, 7V, 8V, 9V, 10V, or any combination thereof.

[0047] In some embodiments, the current density of the electrochemical reaction is 10 mA / cm². 2 ~1000mA / cm 2 This helps accelerate the reaction, improve product quality, and reduce energy consumption. Specifically, the current density of the electrochemical reaction device is 10 mA / cm². 2 100mA / cm 2 150mA / cm 2 160mA / cm 2 170mA / cm 2 180mA / cm 2 190mA / cm 2 200mA / cm 2 210mA / cm 2 220mA / cm 2 230mA / cm 2 240mA / cm 2 250mA / cm 2 500mA / cm 2 700mA / cm 2 1000mA / cm 2or a range consisting of any two of them.

[0048] In some embodiments, the electrochemical reaction apparatus includes a power source, an anode, a cathode, a proton exchange membrane, an anode chamber, and a cathode chamber. The positive terminal of the power source is connected to the anode, and the negative terminal is connected to the cathode. The anode is disposed in the anode chamber, the cathode is disposed in the cathode chamber, and the proton exchange membrane is disposed between the anode and the cathode. The proton exchange membrane is made of perfluorosulfonic acid. The power source provides the electrical energy required for the electrochemical reaction. The anode and cathode perform oxidation and reduction reactions, respectively. The proton exchange membrane allows protons to pass through while blocking electron flow. The anode chamber and cathode chamber respectively contain the anode and cathode, as well as the reaction raw materials and products.

[0049] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0050] Example 1

[0051] I. The electrochemical reaction apparatus of this embodiment includes a power source, an anode, a cathode, a proton exchange membrane, an anode chamber, and a cathode chamber. The positive terminal of the power source is connected to the anode, and the negative terminal is connected to the cathode. The anode is located in the anode chamber, and the cathode is located in the cathode chamber. The proton exchange membrane is located between the anode and the cathode. The proton exchange membrane is Nafion 117 (from Chemours). The anode includes a composite matrix and a perfluorosulfonic acid ionomer (from Chemours) supported on the surface of the composite matrix. The composite matrix includes a titanium fiber felt and an antimony-doped tin oxide coating disposed on the surface of the titanium fiber felt, wherein the coating amount is 5 mg / cm³. 2 The antimony doping level in the coating is 10%, and the loading of perfluorosulfonic acid ionomer on the composite matrix is ​​1 mg / cm³. 2 The cathode comprises a titanium fiber felt and a platinum layer supported on the titanium fiber felt, with a platinum loading of 0.5 mg / cm². 2 .

[0052] II. The preparation of dimethyl sulfoxide in this embodiment includes the following steps:

[0053] Gas-phase dimethyl sulfide, water vapor, and nitrogen were introduced into the anode of the electrochemical reactor at a flow rate of 0.5 mL / min, 0.5 mL / min, and 10 mL / min, respectively. Water was introduced into the cathode of the electrochemical reactor at a flow rate of 2 mL / min. The temperature of the electrochemical reactor was 80 °C. A voltage of 2.3 V was applied between the anode and cathode to carry out the electrochemical reaction, yielding a product containing dimethyl sulfoxide.

[0054] Record the current density of the electrochemical reaction apparatus and plot the current density versus time. For example... Figure 1As shown, the electrochemical reaction device in this embodiment operated stably for 103 hours under the above conditions, with an average current density of 210 mA / cm². 2 The average Faraday efficiency of dimethyl sulfoxide is 80%.

[0055] Example 2

[0056] The difference from Example 1 is that in the preparation of dimethyl sulfoxide, a voltage of 2.1V is applied between the anode and the cathode.

[0057] Example 3

[0058] The difference from Example 1 is that in the preparation of dimethyl sulfoxide, a voltage of 2.5V is applied between the anode and the cathode.

[0059] Example 4

[0060] The difference from Example 1 is that in the preparation of dimethyl sulfoxide, the temperature of the electrochemical reaction device is 60°C, and a voltage of 2.3V is applied between the anode and the cathode.

[0061] Example 5

[0062] The difference from Example 1 is that, in the preparation of dimethyl sulfoxide, gaseous dimethyl sulfide, water vapor, and nitrogen are introduced into the anode of the electrochemical reaction device at a flow rate of 2 mL / min, 2 mL / min, and 10 mL / min.

[0063] Example 6

[0064] The difference from Example 1 is that in the electrochemical reaction device, the composite matrix includes carbon fiber felt and a ruthenium oxide coating disposed on the surface of the carbon fiber felt, wherein the coating amount is 1 mg / cm³. 2 The loading of perfluorosulfonic acid ionomer on the composite matrix was 1 mg / cm³. 2 The cathode comprises a carbon fiber felt and a platinum layer supported on the carbon fiber felt, with a platinum loading of 0.5 mg / cm² on the titanium fiber felt. 2 .

[0065] Example 7

[0066] The difference from Example 1 is that in the electrochemical reaction device, the composite substrate includes a titanium fiber felt and an iridium oxide coating disposed on the surface of the titanium fiber felt, wherein the coating amount is 1 mg / cm³. 2 .

[0067] Example 8

[0068] The difference from Example 1 is that in the electrochemical reaction device, the composite substrate includes a titanium fiber felt and a tantalum oxide coating disposed on the surface of the titanium fiber felt, wherein the coating amount is 1 mg / cm³. 2 .

[0069] Example 9

[0070] The difference from Example 1 is that in the electrochemical reaction device, the composite substrate includes a titanium fiber felt and a lead oxide coating disposed on the surface of the titanium fiber felt, wherein the coating amount is (1 mg / cm³). 2 ).

[0071] Example 10

[0072] The difference from Example 1 is that, in the electrochemical reaction apparatus, the loading of perfluorosulfonic acid ionomer on the composite matrix is ​​0.1 mg / cm³. 2 .

[0073] Example 11

[0074] The difference from Example 1 is that, in the electrochemical reaction apparatus, the loading of perfluorosulfonic acid ionomer on the composite matrix is ​​5 mg / cm³. 2 .

[0075] Comparative Example 1

[0076] The difference from Example 1 is that in the electrochemical reaction device, the anode includes a titanium fiber felt and perfluorosulfonic acid ionomers (Chemours) loaded on the surface of the titanium fiber felt.

[0077] Comparative Example 2

[0078] The difference from Example 1 is that in the electrochemical reaction device, the anode includes a titanium fiber felt and an antimony-doped tin oxide coating disposed on the surface of the titanium fiber felt, wherein the coating amount is 5 mg / cm³. 2 The antimony doping level in the coating is 10%.

[0079] Comparative Example 3

[0080] The difference from Example 1 is that, in the preparation of dimethyl sulfoxide, liquid dimethyl sulfide and liquid water are introduced into the anode of the electrochemical reactor at a flow rate of 0.5 mL / min and a flow rate of 0.5 mL / min, respectively, and water is introduced into the cathode of the electrochemical reactor at a flow rate of 2 mL / min. The temperature of the electrochemical reactor is 80°C, and a voltage of 2.3 V is applied between the anode and the cathode.

[0081] Table 1

[0082]

[0083] As shown in Table 1, compared with the comparative example, the embodiment uses gaseous dimethyl sulfide (DMS) and water vapor as raw materials to oxidize DMS by applying DC voltage in an electrochemical reactor with a specific anode structure, thereby efficiently producing DMSO. The average current density and Faraday efficiency of the electrochemical reaction in the embodiment are much higher than those in the comparative example, indicating that the reaction efficiency and selectivity of the embodiment are much higher than those in the comparative example. Moreover, the method of the embodiment helps to simplify the product separation steps, reduce production costs and environmental impact, and has broad application prospects and market potential.

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing dimethyl sulfoxide, characterized in that, Includes the following steps: A gaseous dimethyl sulfide and water vapor are introduced into the anode of an electrochemical reactor, and water is introduced into the cathode of the electrochemical reactor. A DC voltage is applied between the anode and the cathode to carry out an electrochemical reaction, thereby obtaining a product containing dimethyl sulfoxide. The anode includes a composite matrix and a perfluorosulfonic acid ionomer loaded on the surface of the composite matrix; the composite matrix includes a first substrate and an anti-corrosion coating disposed on the surface of the first substrate, wherein the anti-corrosion coating is made of at least one of ruthenium oxide, iridium oxide, antimony-doped tin oxide, tantalum oxide, and lead oxide.

2. The method for preparing dimethyl sulfoxide according to claim 1, characterized in that, The material of the first substrate includes carbon fiber and / or titanium; and / or, The loading of the perfluorosulfonic acid ionomer on the composite matrix is ​​0.1 mg / cm³. 2 ~5mg / cm 2 ; The amount of the anti-corrosion coating applied to the first substrate is 0.1 mg / cm³. 2 ~10mg / cm 2 .

3. The method for preparing dimethyl sulfoxide according to claim 1 or 2, characterized in that, The cathode includes a second substrate and a platinum catalyst supported on the second substrate; The platinum catalyst comprises particles with a particle size of 1 nm to 10 nm. m-sized platinum particles And / or, the material of the second substrate includes carbon fiber and / or titanium. And / or, the platinum loading in the platinum catalyst on the second substrate is 0.01 mg / cm³. 2 ~5mg / cm 2 ; And / or, the material of the anti-corrosion coating is selected from antimony-doped tin oxide, wherein the antimony doping mass content is 1%~20%, preferably 8%~12%.

4. The method for preparing dimethyl sulfoxide according to any one of claims 1 to 3, characterized in that, The volumetric flow rate ratio of the gaseous dimethyl sulfide to the water vapor is (0.1~10):

1.

5. The method for preparing dimethyl sulfoxide according to any one of claims 1 to 4, characterized in that, The volumetric flow rate ratio of the gaseous dimethyl sulfide to the water is (0.5~2):

2.

6. The method for preparing dimethyl sulfoxide according to any one of claims 1 to 5, characterized in that, The volumetric flow rate of the gaseous dimethyl sulfide is 0.01 mL / min to 1000 mL / min; and / or, The volumetric flow rate of the water vapor is 0.01 mL / min to 1000 mL / min; and / or, The volumetric flow rate of the water is 1 mL / min to 1000 mL / min.

7. The method for preparing dimethyl sulfoxide according to any one of claims 1 to 6, characterized in that, When the gaseous dimethyl sulfide and the water vapor are introduced into the anode of the electrochemical reaction device, the method further includes: introducing nitrogen gas into the anode of the electrochemical reaction device, wherein the flow rate ratio of the gaseous dimethyl sulfide to the nitrogen gas is (0.5~2):

10.

8. The method for preparing dimethyl sulfoxide according to claim 7, characterized in that, The volumetric flow rate of nitrogen gas is 1 mL / min to 1000 mL / min.

9. The method for preparing dimethyl sulfoxide according to any one of claims 1 to 8, characterized in that, The temperature of the electrochemical reaction is 40℃~120℃; and / or, The voltage applied between the anode and the cathode is 1V to 10V; and / or, The current density of the electrochemical reaction is 10 mA / cm². 2 ~1000mA / cm 2 .

10. The method for preparing dimethyl sulfoxide according to any one of claims 1 to 9, characterized in that, The electrochemical reaction device includes a power source, an anode, a cathode, a proton exchange membrane, an anode chamber, and a cathode chamber. The positive terminal of the power source is connected to the anode, and the negative terminal of the power source is connected to the cathode. The anode is disposed in the anode chamber, the cathode is disposed in the cathode chamber, and the proton exchange membrane is disposed between the anode and the cathode. The material of the proton exchange membrane includes perfluorosulfonic acid.

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