Method for preparing sulfoxide through electrocatalytic oxidation of thioether by using heterogeneous catalyst with high Faraday efficiency

Abstract

The invention provides a method for preparing sulfoxide through electrocatalytic oxidation of thioether with a high-Faraday-efficiency heterogeneous catalyst, and belongs to the technical field of electrocatalytic organic synthesis. The method comprises the following steps: dissolving a thioether compound in a solvent to obtain an electrolyte; under the action of a metal oxide coated anode catalyst, an electrocatalytic oxidation reaction is carried out, and reaction liquid is purified to obtain sulfoxide; the solvent is water or a mixed solvent of an organic solvent and water; in the metal oxide coated anode catalyst, the metal in the metal oxide is selected from one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, silver, gold, palladium, platinum, rhodium, iridium, ruthenium, cerium, molybdenum or tungsten. According to the method, the metal oxide coated anode material is used as the catalyst, green and clean water is used as an oxygen source, the reaction condition is mild, the target product sulfoxide can be obtained with high selectivity, high yield, high stability and high Faraday efficiency, excellent electro-catalysis stability is achieved, and the catalyst is easy to recycle and reuse.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalytic organic synthesis, and particularly relates to a method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency. Background Art

[0002] Sulfoxide compounds can be used as important intermediates in drug synthesis and are used to construct complex structures of drug molecules. For example, thionyl chloride can be used to produce a variety of drug intermediates, such as 2-aminothiazoline, 2-furoyl chloride, pivaloyl chloride, 2-oxo-2-furanyl acetic acid, etc. Some chiral sulfoxides are also used in medicine, such as esomeprazole and amodafil. Dimethyl sulfoxide (DMSO) is a commonly used solvent in the pharmaceutical field. It can dissolve many organic and inorganic compounds and plays an important role in the preparation of some poorly soluble drugs. It can promote the absorption and penetration of drugs and improve the bioavailability of drugs. In addition, DMSO also has certain anti-inflammatory, analgesic and antioxidant effects, and is also used in some topical drugs. Sulfoxide compounds can be used to synthesize the active ingredients of some pesticides. For example, thionyl chloride can be used to produce pesticide products such as cypermethrin, deltamethrin, chlorpyrifos, oxazolidinone, and quizalofop-p-butyl.

[0003] Sulfoxide compounds have a wide range of applications in organic synthesis and medicinal chemistry. The use of chiral sulfoxides as auxiliary agents, ligands, catalysts and synthons has been fully demonstrated. The sulfenyl group of sulfoxide compounds can also be used as a pharmacophore, carbonyl bioisostere or drug molecule modification group in drug design and drug development.

[0004] There are reports in the prior art that electrocatalytic oxidation is used to synthesize sulfoxide. For example, patent document CN 111534832 A uses O2 as the oxygen source, which poses safety risks and is flammable and explosive, and the Faradaic efficiency is not mentioned in the text; patent document CN113737206 A uses an equivalent amount of Cl salt as the medium, which essentially oxidizes Cl- into Cl2 at the anode, and then reacts with water to form highly oxidizing ClO2-, etc. The reaction liquid will have residual chlorine-containing wastewater, which will have a huge impact on the environment in terms of post-treatment, and the Faradaic efficiency is not described in the text; patent document CN 118064908 A uses a homogeneous molecular catalyst, which has poor stability and is difficult to recycle and reuse multiple times, and the addition of Sc 3+ Salt, without explaining the principle and function, nor mentioning the Faraday efficiency.

[0005] High Faraday efficiency is one of the cores of electrocatalysis and a sign of effective use of electrical energy. In view of the problem that homogeneous catalysts are difficult to recycle and reuse multiple times and have low Faraday efficiency, it is of great significance to develop a method for preparing sulfoxide by electrocatalytic oxidation of sulfide with high Faraday efficiency, high yield, and easy recycling and reuse of heterogeneous catalysts. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention provides a method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency. In the method for preparing sulfoxide by electrocatalytic oxidation of sulfide of the present invention, a metal oxide-coated anode material is used as a catalyst, green and clean water is used as an oxygen source, the reaction conditions are mild, and the target product sulfoxide can be obtained with high selectivity, high yield, high stability, and high Faraday efficiency. The method has excellent electrocatalytic stability, and the catalyst is easy to recycle and reuse. The technical solution of the present invention is as follows: A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst comprises the following steps: The sulfide compound is dissolved in a solvent to obtain an electrolyte; under the action of a metal oxide-coated anode catalyst, an electrocatalytic oxidation reaction is carried out, and the reaction solution is purified to obtain sulfoxide; The solvent is water or a mixed solvent of an organic solvent and water; in the metal oxide coated anode catalyst, the metal in the metal oxide is selected from one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, silver, gold, palladium, platinum, rhodium, iridium, ruthenium, cerium, molybdenum or tungsten.

[0007] According to the present invention, preferably, the thioether compound is selected from one of the following compounds:

[0008] .

[0009] Preferably according to the present invention, in the mixed solvent of organic solvent and water, the organic solvent is acetonitrile, acetone, ethanol, methanol, toluene, dichloromethane, chloroform, chlorobenzene, DMF, DMA, dioxane, NMP, ether, tetrahydrofuran, butanol, xylene, isopropanol, ethylene glycol or triethylamine; the mass ratio of the organic solvent to water is 0.25-9:1.

[0010] Preferably according to the present invention, the concentration of the thioether compound in the solvent is 1-800 mmol / L.

[0011] Preferably according to the present invention, the mass of the metal oxide in the metal oxide-coated anode catalyst is 1 wt%-40 wt% of the mass of the sulfide compound.

[0012] According to the preferred embodiment of the present invention, the electrolyte also includes an electrolyte; the electrolyte is selected from lithium perchlorate, lithium hexafluorophosphate, sodium chloride, potassium chloride, ammonium chloride, lithium sulfate, lithium nitrate, lithium carbonate, lithium chloride, sodium sulfate, potassium sulfate, ammonium sulfate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium nitrate, potassium nitrate, ammonium nitrate, tetramethylammonium tetrafluoroborate, tetraethylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, tetramethylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, tetramethylammonium acetate, tetraethylammonium acetate, tetrabutylammonium acetate , tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrabutylammonium fluoride, tetramethylammonium hydrogen sulfate, tetraethylammonium hydrogen sulfate, tetrabutylammonium hydrogen sulfate, tetramethylammonium hydrogen carbonate, tetraethylammonium hydrogen carbonate, tetrabutylammonium hydrogen carbonate, tetramethylammonium perchlorate, tetraethylammonium perchlorate, tetrabutylammonium perchlorate, tetramethylammonium nitrate, tetraethylammonium nitrate or tetrabutylammonium nitrate; the concentration of the electrolyte in the solvent is 0.1-1 mol / L.

[0013] According to the present invention, the electrolysis mode used for the electrocatalytic oxidation reaction is preferably constant voltage or constant current; when the electrolysis mode is constant voltage, the counter electrode is a platinum or nickel electrode, the reference electrode is a silver / silver chloride electrode or a saturated calomel electrode, the voltage is 1-1.9 V, and the catalyst is added and immersed in the electrolyte; when the electrolysis mode is constant current, the catalyst is used as the anode, the platinum sheet is used as the cathode, and the current density is 2-2000 mA / cm 2 .

[0014] Preferably according to the present invention, the electrocatalytic oxidation reaction temperature is 25° C.-80° C., the reaction time is 5-100 h, and the reaction is carried out in an air atmosphere.

[0015] According to the present invention, the purification method can be based on existing methods.

[0016] Preferably according to the present invention, the anode in the metal oxide coated anode catalyst is selected from one of a titanium electrode, a platinum electrode, a platinum titanium electrode, a carbon cloth, a carbon paper, a carbon felt, a carbon fiber, a nickel foam or a nickel plate.

[0017] According to a preferred embodiment of the present invention, a method for preparing a metal oxide coated anode catalyst comprises the steps of: A metal salt aqueous solution and a sulfuric acid aqueous solution are mixed as an electrolyte, and a metal oxide is deposited on the surface of the anode electrode by electrochemical deposition to obtain an anode coated with a metal oxide precursor; and then calcined to obtain a metal oxide-coated anode catalyst.

[0018] Preferably, the metal salt is a metal sulfate, a metal nitrate or a metal hydrochloride.

[0019] Preferably, the metal in the metal salt is selected from one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, silver, gold, palladium, platinum, rhodium, iridium, ruthenium, cerium, molybdenum or tungsten.

[0020] Preferably, the metal salt is selected from titanium sulfate, titanium nitrate, titanium chloride, vanadium sulfate, vanadium nitrate, vanadium chloride, chromium sulfate, chromium nitrate, chromium chloride, potassium dichromate, manganese sulfate, manganese nitrate, manganese chloride, ferric sulfate, ferrous sulfate, ferric nitrate, ferrous nitrate, ferric chloride, ferrous chloride, cobalt sulfate, cobalt nitrate, cobalt chloride, nickel sulfate, nickel nitrate, nickel chloride, copper sulfate, copper nitrate, copper chloride, silver sulfate, silver nitrate, silver chloride, gold nitrate, gold chloride, palladium sulfate, palladium nitrate, palladium chloride, platinum sulfite, platinum nitrate, platinum chloride, platinum dichloride, chloroplatinic acid, rhodium sulfate, rhodium nitrate, rhodium chloride, iridium chloride, iridium tetrachloride, platinum sulfate, platinum nitrate, platinum chloride, ammonium molybdate, ruthenium sulfate, ruthenium nitrate, ruthenium chloride, cerium sulfate, cerium nitrate, cerium chloride or tungsten nitrate.

[0021] Preferably, the concentration of the aqueous metal salt solution is 0.1-4 mol / L; the concentration of the aqueous sulfuric acid solution is 0.1-2 mol / L.

[0022] Preferably, in the electrolyte, the molar ratio of the metal salt to sulfuric acid is 0.1-10:1.

[0023] Preferably, the electrochemical deposition temperature is from room temperature to 80°C, and the current density is 1-50 mA / cm 2 , the electrochemical deposition time is 0.5-5h.

[0024] Preferably, the anode used for electrochemical deposition is selected from one of a platinum-titanium electrode, a platinum electrode, a titanium electrode, a carbon cloth, a carbon paper, a carbon felt, a carbon fiber, a nickel foam or a nickel plate; and the cathode used is selected from one of a carbon plate, a carbon cloth, a carbon paper, a carbon fiber, a carbon felt, a platinum electrode, a platinum-titanium electrode, a titanium electrode, a nickel plate or a nickel foam.

[0025] Preferably, the calcination temperature is 300-800° C., the calcination time is 3-6 h, the heating rate is 1-10° C. / min, and the calcination atmosphere is air or oxygen.

[0026] According to the preferred embodiment of the present invention, the metal oxide coated anode catalyst is a manganese oxide coated anode catalyst, and the preparation method thereof comprises the steps of: (1) Route 1: dissolving the manganese source in water, subjecting it to a hydrothermal reaction, and then separating and drying it to obtain manganese oxide; or, Route 2: Mix benzyl alcohol and water evenly, add PVP and perform ultrasound to form an emulsion, add a manganese source aqueous solution dropwise under stirring, react, separate and dry to obtain manganese oxide; (2) Manganese oxide, a conductive agent and a binder are fully dispersed in an organic solvent, and then coated on the surface of the anode material, and dried to obtain a manganese oxide-coated anode catalyst.

[0027] Preferably, in step (1) route 1, the manganese source is one or a combination of KMnO4 or MnSO4; the molar ratio of the manganese source to the volume of water is 0.2-1 mol / L.

[0028] Preferably, in step (1) route 1, the hydrothermal reaction temperature is 150-170° C., and the hydrothermal reaction time is 6-12 h.

[0029] Preferably, in step (1) in route 1, a hydrochloric acid aqueous solution with a mass concentration of 30-37% can be added to the reaction; the volume ratio of the hydrochloric acid aqueous solution to water is 1:120-170.

[0030] Preferably, in step (1) route 2, the volume ratio of benzyl alcohol to water is 1:5-10; the mass ratio of PVP to benzyl alcohol is 5-15 mg / mL; the manganese source is KMnO4, and the concentration of the manganese source aqueous solution is 0.05-1 mol / L; the volume ratio of the manganese source aqueous solution to benzyl alcohol is 2-4:1.

[0031] Preferably, according to the present invention, in step (1) route 2, the reaction temperature is room temperature and the reaction time is 1-5 h.

[0032] According to the preferred embodiment of the present invention, in step (2), the conductive agent is carbon black; the binder is polyvinylidene fluoride (PVDF); the organic solvent is N-methylpyrrolidone; and the mass ratio of manganese oxide, conductive agent and binder is 1-5:1:2-8. Application of sulfoxide prepared by the above method in the preparation of sulfone.

[0033] According to the present invention, the sulfoxide prepared by the above method can be further used to prepare sulfone according to the existing method; preferably, the method for preparing sulfone using the sulfoxide prepared by the above method comprises the steps of: Dissolving sulfoxide in solvent A to obtain an electrolyte; subjecting the electrolyte to electrocatalytic oxidation reaction under the action of catalyst A, and purifying the reaction solution to obtain sulfone; The solvent A is water or a mixed solvent of an organic solvent and water; the catalyst A is a metal oxide coated anode material; wherein the metal in the metal oxide is selected from one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, silver, gold, palladium, platinum, rhodium, iridium, ruthenium, cerium, molybdenum or tungsten; and the anode is selected from one of titanium electrode, platinum electrode, platinum-titanium electrode, carbon cloth, carbon paper, carbon felt, carbon fiber, foam nickel or nickel plate.

[0034] Preferably, in the mixed solvent of organic solvent and water, the organic solvent is acetonitrile, acetone, ethanol, methanol, toluene, dichloromethane, chloroform, chlorobenzene, DMF, DMA, dioxane, NMP, ether, tetrahydrofuran, butanol, xylene, isopropanol, ethylene glycol or triethylamine; the mass ratio of the organic solvent to water is 1:0.25-4.

[0035] Preferably, the concentration of sulfoxide in solvent A is 1-1000 mmol / L.

[0036] Preferably, the mass of the metal oxide in Catalyst A is 0.1 wt%-30 wt% of the mass of the sulfoxide.

[0037] Preferably, an electrolyte is further added to the electrolyte; the electrolyte is selected from lithium perchlorate, lithium hexafluorophosphate, sodium chloride, potassium chloride, ammonium chloride, lithium sulfate, lithium nitrate, lithium carbonate, lithium chloride, sodium sulfate, potassium sulfate, ammonium sulfate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium nitrate, potassium nitrate, ammonium nitrate, tetramethylammonium tetrafluoroborate, tetraethylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, tetramethylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, tetramethylammonium acetate, tetraethylammonium acetate, tetrabutylammonium acetate, tetramethylammonium The electrolyte is selected from the group consisting of tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrabutylammonium fluoride, tetramethylammonium hydrogen sulfate, tetraethylammonium hydrogen sulfate, tetrabutylammonium hydrogen sulfate, tetramethylammonium hydrogen carbonate, tetraethylammonium hydrogen carbonate, tetrabutylammonium hydrogen carbonate, tetramethylammonium perchlorate, tetraethylammonium perchlorate, tetrabutylammonium perchlorate, tetramethylammonium nitrate, tetraethylammonium nitrate and tetrabutylammonium nitrate; and the concentration of the electrolyte in the solvent is 0.1-1 mol / L.

[0038] Preferably, the electrolysis mode used in the electrocatalytic oxidation reaction is constant voltage or constant current; when the electrolysis mode is constant voltage, the counter electrode is a platinum or nickel electrode, the reference electrode is a silver / silver chloride electrode or a saturated calomel electrode, the voltage is 1-2 V, and the catalyst is added and immersed in the electrolyte; when the electrolysis mode is constant current, the catalyst is used as the anode, the platinum sheet is used as the cathode, and the current density is 2-2000 mA / cm 2 .

[0039] Preferably, the electrocatalytic oxidation reaction temperature is 25° C.-80° C., the reaction time is 1-35 h, and the reaction is carried out in an air atmosphere.

[0040] According to the present invention, the preparation method of catalyst A is the same as the preparation method of metal oxide coated anode catalyst used for preparing sulfoxide by electrocatalytic oxidation of sulfide.

[0041] The route of preparing sulfoxide by electrocatalytic oxidation of thioether of the present invention is as follows:

[0042] Sulfide sulfoxide Technical features and beneficial effects of the present invention: 1. The present invention uses a heterogeneous metal oxide-coated anode catalyst, uses cheap chemical sulfide, water, etc. as raw materials, uses electrical energy as an energy source, promotes water splitting, and transfers the generated oxygen atoms to sulfide to synthesize sulfoxide. The method of the present invention is efficient, green, safe and environmentally friendly, has high atom economy, simple steps, mild reaction conditions, low price, avoids the use of non-precious metal catalysts and chemical oxidants, such as chlorine or peroxyacid and other hazardous chemicals, does not cause safety problems and harmful waste residue problems, and is suitable for industrial applications.

[0043] 2. The heterogeneous catalyst used in the present invention has a simple preparation method, and the raw materials are cheap and readily available, which is green and environmentally friendly and low in cost. The catalyst of the present invention is conducive to the adsorption of reactants on the catalyst, thereby accelerating the reaction. The catalyst of the present invention uses the anode electrode as the catalyst substrate, and the obtained catalyst is more stable and easy to recycle and has higher reusability.

[0044] 3. The present invention uses water as a raw material, and water provides an oxygen source. Water is activated and decomposed under the action of a catalyst to form an oxygen-containing intermediate. The intermediate acts as an active species to highly selectively oxidize sulfide to sulfoxide, with high conversion rate and product yield, high reaction selectivity, high Faraday efficiency, and good electrocatalytic stability.

[0045] 4. The method of the present invention has a high Faraday efficiency. High Faraday efficiency is one of the core elements of electrocatalysis and a sign of effective use of electrical energy, which means that most of the electricity passing through the electrode is effectively used to generate the desired target product rather than being consumed in other side reactions. High Faraday efficiency indicates that the charge transfer step can be carried out more efficiently, that is, the ions or molecules involved in the reaction can quickly acquire or lose electrons from the electrode and be converted into the target product. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a SEM image of the manganese oxide-coated anode catalyst prepared in Example 1; Figure 2 This is a stability test chart of the catalyst prepared in Example 1.

[0047] Figure 3 This is a recycling test diagram of the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0048] The present invention will be further described below with reference to specific embodiments, but is not limited thereto.

[0049] Meanwhile, the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0050] Example 1 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst comprises the following steps: (1) Mix 300 mL of 0.04 mol / L manganese nitrate aqueous solution and 200 mL of 0.5 mol / L sulfuric acid aqueous solution as the electrolyte, use a titanium electrode as the anode with a size of 2*200*200 mm, and a carbon plate as the cathode. The size of the cathode electrode should be the same as or slightly larger than that of the anode. Use 20 mA / cm 2 The electrochemical deposition reaction was carried out at a current density of 3 hours, and the uncoated part was cut off to obtain the anode coated with the metal oxide precursor.

[0051] (2) The anode coated with the metal oxide precursor obtained above was placed in a muffle furnace, heated to 300°C at a heating rate of 5°C / min and continued for 6 hours in an air calcination atmosphere to obtain a manganese oxide coated anode catalyst.

[0052] (3) The following operation was performed at 25°C. 0.5 mmol (31 mg) of dimethyl sulfide, 2*10*20 mm of the catalyst prepared by the above method (the catalyst was immersed in the electrolyte, in which the mass of manganese oxide was 10 wt% of the mass of dimethyl sulfide), 1 mL of water and 9 mL of acetonitrile were added to a three-necked flask reactor equipped with a magnetic stirring magnet. Lithium perchlorate electrolyte (the concentration of the electrolyte in the solvent was 0.1 mol / L) was added and mixed thoroughly to form the electrolyte. In an air atmosphere, a silver / silver chloride electrode was used as a reference electrode and a platinum sheet was used as a counter electrode. The reaction was carried out at a constant voltage of 1.7 V at 25°C for 5 hours. After the reaction was completed, the filtrate was filtered and vacuum dried to obtain the product dimethyl sulfoxide with a yield of 98% and a Faraday efficiency of 99% (conversion rate of dimethyl sulfide was 99%, and reaction selectivity was 99%).

[0053] The SEM image of the catalyst prepared in this example is as follows Figure 1 As shown in the figure, it can be seen that the prepared sample is a nanowire structure.

[0054] Stability test: The specific test conditions are to add 360 mg of lithium perchlorate and 10 mL of dimethyl sulfide to a 15 mL mixed solution of water and acetonitrile (the volume ratio of water to acetonitrile is 1:9), mix well, add 2*10*20 mm catalyst as electrolyte; in an air atmosphere, use a silver / silver chloride electrode as a reference electrode and a platinum sheet as a counter electrode, and react at a constant voltage of 1.6V at 25°C for 100 hours. Figure 2 It can be seen that the catalyst has good stability.

[0055] Recycling test: After the reaction in step (3) of this embodiment is completed, the reaction solution is filtered to obtain a catalyst; the catalyst is further used to prepare dimethyl sulfoxide according to the method in step (3) of this embodiment, and the obtained reaction solution is filtered to obtain a catalyst; the above steps are repeated 8 times, that is, the catalyst is used to prepare dimethyl sulfoxide 10 times in total.

[0056] The yield of dimethyl sulfoxide is Figure 3 As shown, the initial product yield is 98%. As the number of cycles increases, the product yield decreases slightly, but the overall yield is above 90%, indicating that the catalyst of the present invention has good reusability.

[0057] Example 2 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (1), the electrodeposition temperature is changed from room temperature to 50° C., and the other steps and conditions are the same as in Example 1.

[0058] In this example, the conversion rate of dimethyl sulfide was 96%, the reaction selectivity was 95%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0059] Example 3 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (1), the electrodeposition temperature is changed from room temperature to 80° C. The other steps and conditions are the same as in Example 1.

[0060] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 90%, the yield of the target product is 86%, and the Faraday efficiency is 88%.

[0061] Example 4 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (2), the calcination temperature is changed from 300° C. to 550° C., and the other steps and conditions are the same as those in Example 1.

[0062] In this example, the conversion rate of dimethyl sulfide is 96%, the reaction selectivity is 94%, the yield of the target product is 90%, and the Faraday efficiency is 92%.

[0063] Example 5 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (2), the calcination temperature is changed from 300° C. to 700° C., and the other steps and conditions are the same as those in Example 1.

[0064] In this example, the conversion rate of dimethyl sulfide was 96%, the reaction selectivity was 97%, the yield of the target product was 93%, and the Faraday efficiency was 95%.

[0065] Example 6 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (3), the reaction temperature is changed from 25° C. to 40° C. The other steps and conditions are the same as in Example 1.

[0066] In this example, the conversion rate of dimethyl sulfide is 93%, the reaction selectivity is 97%, the yield of the target product is 90%, and the Faraday efficiency is 92%.

[0067] Example 7 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (3), the reaction temperature is changed from 25° C. to 80° C. The other steps and conditions are the same as in Example 1.

[0068] In this example, the conversion rate of dimethyl sulfide was 97%, the reaction selectivity was 95%, the yield of the target product was 92%, and the Faraday efficiency was 94%.

[0069] Example 8 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (1), the amount of 0.04 mol / L manganese nitrate aqueous solution is 30 mL; in step (3), the mass of manganese oxide in the catalyst is 1 wt% of the mass of methyl sulfide, and the catalyst size is 2*10*20 mm. The other steps and conditions are the same as in Example 1.

[0070] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 90%, the yield of the target product is 86%, and the Faraday efficiency is 88%.

[0071] Example 9 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (1), the amount of 0.04 mol / L manganese nitrate aqueous solution is 1200 mL; in step (3), the mass of manganese oxide in the catalyst is 40 wt% of the mass of methyl sulfide, and the catalyst size is 2*10*20 mm. The other steps and conditions are the same as in Example 1.

[0072] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 96%, the yield of the target product is 90%, and the Faraday efficiency is 92%.

[0073] Example 10 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst comprises the following steps: (1) Dissolve KMnO4 and MnSO4 in 40 mL of water, where the concentration of KMnO4 is 0.24 mol / L and the concentration of MnSO4 is 0.53 mol / L. Stir for 30 min, place in a polytetrafluoroethylene hydrothermal reactor and hydroheat at 160°C for 12 h. Centrifuge and dry to obtain MnO2.

[0074] (2) Take 20 mg of MnO2, 10 mg of carbon black, and 4 mg of PVDF, disperse them in 400 μL of N-methylpyrrolidone, and drop 25 μL each time on a 1*1 cm titanium electrode, once every half an hour, for a total of four times. Finally, dry to obtain a manganese oxide-coated anode catalyst.

[0075] (3) Same as step (3) of Example 1.

[0076] In this example, the conversion rate of dimethyl sulfide was 98%, the reaction selectivity was 96%, the yield of the target product was 94%, and the Faraday efficiency was 96%.

[0077] Embodiment 11 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst comprises the following steps: (1) Dissolve MnSO4 in 30 mL of water, where the concentration of MnSO4 is 0.3 mol / L. Stir for 30 minutes, place in a polytetrafluoroethylene hydrothermal reactor and hydroheat at 170°C for 10 h. Centrifuge and dry to obtain MnO2.

[0078] (2) Take 20 mg of MnO2, 10 mg of carbon black, and 4 mg of PVDF, disperse them in 400 μL of N-methylpyrrolidone, and drop 25 μL each time on a 1*1 cm titanium electrode, once every half an hour, for a total of four times. Finally, dry to obtain a manganese oxide-coated anode catalyst.

[0079] (3) Same as step (3) of Example 1.

[0080] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 95%, the yield of the target product is 90%, and the Faraday efficiency is 92%.

[0081] Example 12 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst comprises the following steps: (1) Dissolve KMnO4 and MnSO4 in 40 mL of water, where the concentration of KMnO4 is 0.5 mol / L and the concentration of MnSO4 is 0.18 mol / L. Stir for 30 min, place in a polytetrafluoroethylene hydrothermal reactor and hydroheat at 160°C for 12 h. Centrifuge and dry to obtain MnO2.

[0082] (2) Take 20 mg of MnO2, 10 mg of carbon black, and 4 mg of PVDF, disperse them in 400 μl of N-methylpyrrolidone, and drop 25 μl each time on a 1*1 cm titanium electrode, once every half an hour, for a total of four times. Finally, dry to obtain the catalyst for preparing sulfoxide.

[0083] (3) Same as step (3) of Example 1.

[0084] In this example, the conversion rate of dimethyl sulfide was 95%, the reaction selectivity was 96%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0085] Example 13 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst comprises the following steps: (1) Mix 1 mL of benzyl alcohol and 7 mL of water evenly, add 10 mg of PVP and sonicate until an emulsion is formed. Stir vigorously and add 3 mL of 0.1 mol / L KMnO4 aqueous solution dropwise. Stir at room temperature for 2 h, centrifuge and dry to obtain MnO2.

[0086] (2) Take 20 mg of MnO2, 10 mg of carbon black, and 4 mg of PVDF, disperse them in 400 μl of N-methylpyrrolidone, and drop 25 μl each time on a 1*1 cm titanium electrode, once every half an hour, for a total of four times. Finally, dry to obtain the catalyst for preparing sulfoxide.

[0087] (3) Same as step (3) of Example 1. In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 97%, the yield of the target product is 92%, and the Faraday efficiency is 94%.

[0088] Embodiment 14 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst comprises the following steps: (1) Dissolve KMnO4 and 0.2 mL of 36.5% hydrochloric acid aqueous solution in 30 mL of water, where the concentration of KMnO4 is 0.4 mol / L. Stir for 30 min, place in a polytetrafluoroethylene hydrothermal autoclave, hydroheat at 150°C for 6 h, centrifuge and dry to obtain MnO2.

[0089] (2) Take 20 mg of MnO2, 10 mg of carbon black, and 4 mg of PVDF, disperse them in 400 μl of N-methylpyrrolidone, and drop 25 μl each time on a 1*1 cm titanium electrode, once every half an hour, for a total of four times. Finally, dry to obtain the catalyst for preparing sulfoxide.

[0090] (3) Same as step (3) of Example 1.

[0091] In this example, the conversion rate of dimethyl sulfide is 93%, the reaction selectivity is 95%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0092] Embodiment 15 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.04 mol / L ferric chloride aqueous solution. In step (2), the calcination temperature is changed to 550° C. The other steps and conditions are the same as those in Example 1.

[0093] In this example, the conversion rate of dimethyl sulfide was 97%, the reaction selectivity was 92%, the yield of the target product was 89%, and the Faraday efficiency was 91%.

[0094] Example 16 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.04 mol / L cobalt nitrate aqueous solution. In step (2), the calcination temperature is changed to 550° C. The other steps and conditions are the same as those in Example 1.

[0095] In this example, the conversion rate of methyl sulfide was 93%, the reaction selectivity was 98%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0096] Embodiment 17 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.04 mol / L nickel nitrate aqueous solution. In step (2), the calcination temperature is changed to 550° C. The other steps and conditions are the same as those in Example 1.

[0097] In this example, the conversion rate of dimethyl sulfide was 94%, the reaction selectivity was 94%, the yield of the target product was 88%, and the Faraday efficiency was 93%.

[0098] Embodiment 18 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.06 mol / L copper nitrate aqueous solution. In step (1), the calcination temperature is changed to 550° C. The other steps and conditions are the same as in Example 1.

[0099] In this example, the conversion rate of dimethyl sulfide is 96%, the reaction selectivity is 93%, the yield of the target product is 89%, and the Faraday efficiency is 91%.

[0100] Embodiment 19 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.04 mol / L silver nitrate aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0101] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 96%, the yield of the target product is 90%, and the Faraday efficiency is 92%.

[0102] Embodiment 20 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.04 mol / L palladium chloride aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0103] In this example, the conversion rate of dimethyl sulfide is 98%, the reaction selectivity is 94%, the yield of the target product is 92%, and the Faraday efficiency is 94%.

[0104] Embodiment 21 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.05 mol / L chloroplatinic acid aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0105] In this example, the conversion rate of dimethyl sulfide is 97%, the reaction selectivity is 91%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0106] Embodiment 22 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.03 mol / L rhodium nitrate aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0107] In this example, the conversion rate of dimethyl sulfide is 93%, the reaction selectivity is 97%, the yield of the target product is 90%, and the Faraday efficiency is 92%.

[0108] Embodiment 23 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.07 mol / L iridium chloride aqueous solution. In step (2), the calcination temperature is changed to 800° C. The other steps and conditions are the same as in Example 1.

[0109] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 95%, the yield of the target product is 89%, and the Faraday efficiency is 91%.

[0110] Embodiment 24 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.08 mol / L cerium chloride aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0111] In this example, the conversion rate of dimethyl sulfide was 95%, the reaction selectivity was 97%, the yield of the target product was 92%, and the Faraday efficiency was 94%.

[0112] Embodiment 25 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.06 mol / L potassium dichromate aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0113] In this example, the conversion rate of methyl sulfide was 95%, the reaction selectivity was 96%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0114] Embodiment 26 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a heterogeneous catalyst having high Faraday efficiency is as described in Example 1, except that in step (1), the 0.04 mol / L aqueous solution of manganese nitrate is replaced with a 0.04 mol / L aqueous solution of ammonium molybdate, and the other steps and conditions are the same as those in Example 1.

[0115] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 98%, the yield of the target product is 92%, and the Faraday efficiency is 94%.

[0116] Embodiment 27 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, as described in Example 1, except that: In step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.04 mol / L tungsten nitrate aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0117] In this example, the conversion rate of dimethyl sulfide is 97%, the reaction selectivity is 91%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0118] Embodiment 28 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is as described in Example 1, except that in step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.04 mol / L vanadium nitrate aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0119] In this example, the conversion rate of dimethyl sulfide was 93%, the reaction selectivity was 96%, the yield of the target product was 89%, and the Faraday efficiency was 91%.

[0120] Embodiment 29 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst is described in Example 1, except that in step (1), the 0.04 mol / L manganese nitrate aqueous solution is replaced with a 0.04 mol / L titanium nitrate aqueous solution, and the other steps and conditions are the same as those in Example 1.

[0121] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 95%, the yield of the target product is 89%, and the Faraday efficiency is 90%.

[0122] Embodiment 30 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:acetonitrile = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0123] In this example, the conversion rate of dimethyl sulfide is 98%, the reaction selectivity is 93%, the yield of the target product is 91%, and the Faraday efficiency is 93%.

[0124] Embodiment 31 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:acetonitrile = 1:2 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0125] In this example, the conversion rate of dimethyl sulfide was 91%, the reaction selectivity was 96%, the yield of the target product was 87%, and the Faraday efficiency was 89%.

[0126] Embodiment 32 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:acetonitrile = 1:0.5 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0127] In this example, the conversion rate of dimethyl sulfide was 97%, the reaction selectivity was 97%, the yield of the target product was 94%, and the Faraday efficiency was 96%.

[0128] Embodiment 33 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:acetonitrile = 1:0.25 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0129] In this example, the conversion rate of dimethyl sulfide is 90%, the reaction selectivity is 97%, the yield of the target product is 87%, and the Faraday efficiency is 89%.

[0130] Embodiment 34 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:acetone = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0131] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 93%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0132] Embodiment 35 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:ethanol = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0133] In this example, the conversion rate of dimethyl sulfide was 96%, the reaction selectivity was 96%, the yield of the target product was 92%, and the Faraday efficiency was 96%.

[0134] Embodiment 36 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:methanol = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0135] In this example, the conversion rate of dimethyl sulfide was 94%, the reaction selectivity was 93%, the yield of the target product was 87%, and the Faraday efficiency was 88%.

[0136] Embodiment 37 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:toluene = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0137] In this example, the conversion rate of dimethyl sulfide is 91%, the reaction selectivity is 97%, the yield of the target product is 88%, and the Faraday efficiency is 88%.

[0138] Embodiment 38 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water: dichloromethane = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0139] In this example, the conversion rate of dimethyl sulfide is 98%, the reaction selectivity is 92%, the yield of the target product is 90%, and the Faraday efficiency is 90%.

[0140] Embodiment 39 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water: chloroform = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0141] In this example, the conversion rate of dimethyl sulfide is 90%, the reaction selectivity is 97%, the yield of the target product is 87%, and the Faraday efficiency is 89%.

[0142] Embodiment 40 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:chlorobenzene = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0143] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 97%, the yield of the target product is 91%, and the Faraday efficiency is 86%.

[0144] Embodiment 41 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:DMF=1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0145] In this example, the conversion rate of dimethyl sulfide is 92%, the reaction selectivity is 98%, the yield of the target product is 90%, and the Faraday efficiency is 90%.

[0146] Embodiment 42 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:DMA=1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0147] In this example, the conversion rate of dimethyl sulfide is 97%, the reaction selectivity is 90%, the yield of the target product is 87%, and the Faraday efficiency is 90%.

[0148] Embodiment 43 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:dioxane = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0149] In this example, the conversion rate of dimethyl sulfide is 93%, the reaction selectivity is 98%, the yield of the target product is 91%, and the Faraday efficiency is 92%.

[0150] Embodiment 44 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:NMP (N-methylpyrrolidone) = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0151] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 93%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0152] Embodiment 45 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water: ether = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0153] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 95%, the yield of the target product is 90%, and the Faraday efficiency is 93%.

[0154] Embodiment 46 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:tetrahydrofuran (THF) = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0155] In this example, the conversion rate of dimethyl sulfide is 97%, the reaction selectivity is 91%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0156] Embodiment 47 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:butanol=1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0157] In this example, the conversion rate of dimethyl sulfide was 93%, the reaction selectivity was 96%, the yield of the target product was 89%, and the Faraday efficiency was 91%.

[0158] Embodiment 48 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:xylene = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0159] In this example, the conversion rate of dimethyl sulfide is 92%, the reaction selectivity is 97%, the yield of the target product is 89%, and the Faraday efficiency is 91%.

[0160] Embodiment 49 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:isopropanol = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0161] In this example, the conversion rate of dimethyl sulfide was 97%, the reaction selectivity was 93%, the yield of the target product was 90%, and the Faraday efficiency was 91%.

[0162] Embodiment 50 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:ethylene glycol = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0163] In this example, the conversion rate of dimethyl sulfide was 91%, the reaction selectivity was 98%, the yield of the target product was 89%, and the Faraday efficiency was 91%.

[0164] Embodiment 51 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the solvent is changed to a mixed solution of water:triethylamine = 1:1 (volume ratio), and the other steps and conditions are the same as those in Example 1.

[0165] In this example, the conversion rate of dimethyl sulfide is 98%, the reaction selectivity is 95%, the yield of the target product is 93%, and the Faraday efficiency is 95%.

[0166] Embodiment 52 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to sodium nitrate, and the other steps and conditions are the same as those in Example 1.

[0167] In this example, the conversion rate of dimethyl sulfide is 96%, the reaction selectivity is 93%, the yield of the target product is 89%, and the Faraday efficiency is 91%.

[0168] Embodiment 53 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to lithium hexafluorophosphate, and the other steps and conditions are the same as those in Example 1.

[0169] In this example, the conversion rate of dimethyl sulfide was 95%, the reaction selectivity was 96%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0170] Embodiment 54 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to lithium nitrate, and the other steps and conditions are the same as those in Example 1.

[0171] In this example, the conversion rate of dimethyl sulfide is 91%, the reaction selectivity is 97%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0172] Embodiment 55 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to potassium nitrate, and the other steps and conditions are the same as those in Example 1.

[0173] In this example, the conversion rate of dimethyl sulfide was 91%, the reaction selectivity was 98%, the yield of the target product was 89%, and the Faraday efficiency was 91%.

[0174] Embodiment 56 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium tetrafluoroborate, and the other steps and conditions are the same as those in Example 1.

[0175] In this example, the conversion rate of dimethyl sulfide is 96%, the reaction selectivity is 93%, the yield of the target product is 89%, and the Faraday efficiency is 91%.

[0176] Embodiment 57 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to ammonium nitrate, and the other steps and conditions are the same as those in Example 1.

[0177] In this example, the conversion rate of dimethyl sulfide is 89%, the reaction selectivity is 90%, the yield of the target product is 80%, and the Faraday efficiency is 82%.

[0178] Embodiment 58 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium hexafluorophosphate, and the other steps and conditions are the same as those in Example 1.

[0179] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 98%, the yield of the target product is 93%, and the Faraday efficiency is 95%.

[0180] Embodiment 59 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium acetate, and the other steps and conditions are the same as those in Example 1.

[0181] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 95%, the yield of the target product is 89%, and the Faraday efficiency is 91%.

[0182] Embodiment 60 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium chloride, and the other steps and conditions are the same as those in Example 1.

[0183] In this example, the conversion rate of dimethyl sulfide is 92%, the reaction selectivity is 95%, the yield of the target product is 87%, and the Faraday efficiency is 89%.

[0184] Embodiment 61 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium bromide, and the other steps and conditions are the same as those in Example 1.

[0185] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 94%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0186] Embodiment 62 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium fluoride, and the other steps and conditions are the same as those in Example 1.

[0187] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 92%, the yield of the target product is 87%, and the Faraday efficiency is 89%.

[0188] Embodiment 63 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium hydrogen sulfate, and the other steps and conditions are the same as those in Example 1.

[0189] In this example, the conversion rate of dimethyl sulfide is 92%, the reaction selectivity is 98%, the yield of the target product is 90%, and the Faraday efficiency is 95%.

[0190] Embodiment 64 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium bicarbonate, and the other steps and conditions are the same as those in Example 1.

[0191] In this example, the conversion rate of dimethyl sulfide is 93%, the reaction selectivity is 97%, the yield of the target product is 90%, and the Faraday efficiency is 91%.

[0192] Embodiment 65 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium perchlorate, and the other steps and conditions are the same as those in Example 1.

[0193] In this example, the conversion rate of dimethyl sulfide is 93%, the reaction selectivity is 98%, the yield of the target product is 91%, and the Faraday efficiency is 94%.

[0194] Embodiment 66 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the electrolyte is changed to tetrabutylammonium nitrate, and the other steps and conditions are the same as those in Example 1.

[0195] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 94%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0196] Embodiment 67 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced by diphenyl sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0197] In this example, the conversion rate of diphenyl sulfide is 92%, the reaction selectivity is 99%, the yield of the target product is 91%, and the Faraday efficiency is 95%.

[0198] Embodiment 68 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced by methyl phenyl sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0199] In this example, the conversion rate of methyl phenyl sulfide is 92%, the reaction selectivity is 97%, the yield of the target product is 89%, and the Faraday efficiency is 91%.

[0200] Embodiment 69 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced with p-chlorophenyl methyl sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0201] In this example, the conversion rate of p-chlorophenyl methyl sulfide was 93%, the reaction selectivity was 98%, the yield of the target product was 91%, and the Faraday efficiency was 94%.

[0202] Embodiment 70 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced with 4-methylthiobenzonitrile (structural formula: ), other steps and conditions are the same as in Example 1.

[0203] In this example, the conversion rate of 4-methylthiobenzonitrile was 94%, the reaction selectivity was 98%, the yield of the target product was 92%, and the Faraday efficiency was 95%.

[0204] Embodiment 71 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced by methyl (m-toluene) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0205] In this example, the conversion rate of methyl (m-toluene) sulfide is 95%, the reaction selectivity is 97%, the yield of the target product is 92%, and the Faraday efficiency is 95%.

[0206] Embodiment 72 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced by (2-chlorophenyl)(methyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0207] In this example, the conversion rate of (2-chlorophenyl)(methyl) sulfide was 94%, the reaction selectivity was 96%, the yield of the target product was 90%, and the Faraday efficiency was 92%.

[0208] Embodiment 73 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced with (3,5-dichlorophenyl)(methyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0209] In this example, the conversion rate of (3,5-dichlorophenyl)(methyl) sulfide was 90%, the reaction selectivity was 92%, the yield of the target product was 83%, and the Faraday efficiency was 91%.

[0210] Embodiment 74 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with thiobenzopyran-4-one (structural formula: ), other steps and conditions are the same as in Example 1.

[0211] In this example, the conversion rate of thiobenzopyran-4-one was 93%, the reaction selectivity was 98%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0212] Embodiment 75 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 2-methylthiopyridine (structural formula: ), other steps and conditions are the same as in Example 1.

[0213] In this example, the conversion rate of 2-methylthiopyridine was 95%, the reaction selectivity was 95%, the yield of the target product was 90%, and the Faraday efficiency was 92%.

[0214] Embodiment 76 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced with tetrahydrothiopyran (structural formula: ), other steps and conditions are the same as in Example 1.

[0215] In this example, the conversion rate of tetrahydrothiopyran was 86%, the reaction selectivity was 95%, the yield of the target product was 82%, and the Faraday efficiency was 83%.

[0216] Embodiment 77 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with cyclopropyl (phenyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0217] In this example, the conversion rate of cyclopropyl (phenyl) sulfide is 95%, the reaction selectivity is 94%, the yield of the target product is 89%, and the Faraday efficiency is 91%.

[0218] Embodiment 78 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by dibenzo[b,d]thiophene (structural formula: ), other steps and conditions are the same as in Example 1.

[0219] In this example, the conversion rate of dibenzo[b,d]thiophene is 95%, the reaction selectivity is 93%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0220] Embodiment 79 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with (2-methyl-4-nitrophenyl)(4-(trifluoromethyl)phenyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0221] In this example, the conversion rate of (2-methyl-4-nitrophenyl)(4-(trifluoromethyl)phenyl)sulfide was 92%, the reaction selectivity was 98%, the yield of the target product was 90%, and the Faraday efficiency was 94%.

[0222] Embodiment 80 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 2-(methylthio)-1,2-benzo[d]imidazole (structural formula: ), other steps and conditions are the same as in Example 1.

[0223] In this example, the conversion rate of 2-(methylthio)-11-2-benzo[d]imidazole was 93%, the reaction selectivity was 98%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0224] Embodiment 81 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 2-(methylthio)benzo[d]oxazole (structural formula: ), other steps and conditions are the same as in Example 1.

[0225] In this example, the conversion rate of 2-(methylthio)benzo[d]oxazole was 95%, the reaction selectivity was 97%, the yield of the target product was 92%, and the Faraday efficiency was 95%.

[0226] Embodiment 82 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by (3,5-dibromophenyl)(methyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0227] In this example, the conversion rate of (3,5-dibromophenyl)(methyl)benzene sulfide was 95%, the reaction selectivity was 95%, the yield of the target product was 90%, and the Faraday efficiency was 95%.

[0228] Embodiment 83 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 2-methylthiopyridine (structural formula: ), other steps and conditions are the same as in Example 1.

[0229] In this example, the conversion rate of 2-methylthiopyridine was 95%, the reaction selectivity was 93%, the yield of the target product was 88%, and the Faraday efficiency was 90%.

[0230] Embodiment 84 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced by (4-bromophenyl)(methyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0231] In this example, the conversion rate of (4-bromophenyl)(methyl)sulfide was 92%, the reaction selectivity was 96%, the yield of the target product was 88%, and the Faraday efficiency was 90%.

[0232] Embodiment 85 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced by 4-methoxyphenyl sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0233] In this example, the conversion rate of 4-methoxyphenyl sulfide was 98%, the reaction selectivity was 91%, the yield of the target product was 89%, and the Faraday efficiency was 91%.

[0234] Embodiment 86 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by methyl (4-nitrophenyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0235] In this example, the conversion rate of methyl (4-nitrophenyl) sulfide is 97%, the reaction selectivity is 92%, the yield of the target product is 89%, and the Faraday efficiency is 90%.

[0236] Embodiment 87 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 5-(2-(octylthio)propyl)benzo[d][1,3]dioxole (structural formula: ), other steps and conditions are the same as in Example 1.

[0237] In this example, the conversion rate of 5-(2-(octylthio)propyl)benzo[d][1,3]dioxole was 91%, the reaction selectivity was 98%, the yield of the target product was 89%, and the Faraday efficiency was 91%.

[0238] Embodiment 88 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 5-chloro-6-(2,3-dichlorophenoxy)-2-(methylthio)-3-(2-benzo[d]imidazole (structural formula: ), other steps and conditions are the same as in Example 1.

[0239] In this example, the conversion rate of 5-chloro-6-(2,3-dichlorophenoxy)-2-(methylthio)-3L2-benzo[d]imidazole was 91%, the reaction selectivity was 98%, the yield of the target product was 89%, and the Faraday efficiency was 92%.

[0240] Embodiment 89 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with (6-(propylthio)-1H-benzo[d]imidazol-2-yl)carbamate (structural formula: ), other steps and conditions are the same as in Example 1.

[0241] In this example, the conversion rate of (6-(propylthio)-1H-benzo[d]imidazol-2-yl)carbamic acid methyl ester was 93%, the reaction selectivity was 97%, the yield of the target product was 90%, and the Faraday efficiency was 92%.

[0242] Embodiment 90 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with methyl (6-(phenylthio)-1H-benzo[d]imidazol-2-yl)carbamate (structural formula: ), other steps and conditions are the same as in Example 1.

[0243] In this example, the conversion rate of (6-(phenylthio)-1H-benzo[d]imidazol-2-yl)carbamic acid methyl ester was 91%, the reaction selectivity was 98%, the yield of the target product was 89%, and the Faraday efficiency was 92%.

[0244] Embodiment 91 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 3-(2-chloro-10H-phenothiazine-10-yl)-N,N-dimethyl-1-propylamine (structural formula: ), other steps and conditions are the same as in Example 1.

[0245] In this example, the conversion rate of 3-(2-chloro-10H-phenothiazine-10-yl)-N,N-dimethyl-1-propylamine was 93%, the reaction selectivity was 93%, the yield of the target product was 86%, and the Faraday efficiency was 90%.

[0246] Embodiment 92 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 2-(4-(3-(2-chloro-10H-phenothiazin-10-yl)propyl)piperazin-1-yl)ethanol (structural formula: ), other steps and conditions are the same as in Example 1.

[0247] In this example, the conversion rate of 2-(4-(3-(2-chloro-10H-phenothiazin-10-yl)propyl)piperazin-1-yl)ethanol was 93%, the reaction selectivity was 96%, the yield of the target product was 89%, and the Faraday efficiency was 93%.

[0248] Embodiment 93 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by (2-phenoxyethyl)(m-tolyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0249] In this example, the conversion rate of (2-phenoxyethyl)(m-tolyl) sulfide was 93%, the reaction selectivity was 95%, the yield of the target product was 88%, and the Faraday efficiency was 90%.

[0250] Embodiment 94 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 4-methyldibenzo[b,d]thiophene (structural formula: ), other steps and conditions are the same as in Example 1.

[0251] In this example, the conversion rate of 4-methyldibenzo[b,d]thiophene was 91%, the reaction selectivity was 95%, the yield of the target product was 86%, and the Faraday efficiency was 88%.

[0252] Embodiment 95 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 4,6-dimethyldibenzo[b,d]thiophene (structural formula: ), other steps and conditions are the same as in Example 1.

[0253] In this example, the conversion rate of 4,6-dimethyldibenzo[b,d]thiophene was 93%, the reaction selectivity was 98%, the yield of the target product was 91%, and the Faraday efficiency was 94%.

[0254] Embodiment 96 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 2-aminothiazole (structural formula: ), other steps and conditions are the same as in Example 1.

[0255] In this example, the conversion rate of 2-aminothiazole was 97%, the reaction selectivity was 93%, the yield of the target product was 90%, and the Faraday efficiency was 92%.

[0256] Embodiment 97 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)sulfur)-5,5-dimethyl-4,5-dihydroisoxazole (structural formula: ), other steps and conditions are the same as in Example 1.

[0257] In this example, the conversion rate of 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole was 92%, the reaction selectivity was 98%, the yield of the target product was 90%, and the Faraday efficiency was 96%.

[0258] Embodiment 98 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methylthio-1H-benzimidazole (structural formula: ), other steps and conditions are the same as in Example 1.

[0259] In this example, the conversion rate of 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methylthio-1H-benzimidazole was 90%, the reaction selectivity was 98%, the yield of the target product was 88%, and the Faraday efficiency was 92%.

[0260] Embodiment 99 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 2-(phenylhydrazinethio)acetamide (structural formula: ), other steps and conditions are the same as in Example 1.

[0261] In this example, the conversion rate of 2-(phenylhydrazinethio)acetamide was 95%, the reaction selectivity was 92%, the yield of the target product was 87%, and the Faraday efficiency was 89%.

[0262] Embodiment 100 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced by bis(4-chlorophenyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0263] In this example, the conversion rate of bis(4-chlorophenyl)sulfide was 93%, the reaction selectivity was 96%, the yield of the target product was 89%, and the Faraday efficiency was 91%.

[0264] Embodiment 101 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 4,4'-thiodiphenol (structural formula: ), other steps and conditions are the same as in Example 1.

[0265] In this example, the conversion rate of 4,4'-thiodiphenol was 94%, the reaction selectivity was 97%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0266] Embodiment 102 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by methyl (p-tolyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0267] In this example, the conversion rate of methyl (p-tolyl) sulfide is 95%, the reaction selectivity is 97%, the yield of the target product is 92%, and the Faraday efficiency is 93%.

[0268] Embodiment 103 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 2,2-dichloro-N-((1R,2S)-3-fluoro-1-hydroxy-1-(4-(methylthio)phenyl)propan-2-yl)acetamide (structural formula: ), other steps and conditions are the same as in Example 1.

[0269] In this example, the conversion rate of 2,2-dichloro-N-((1R,2S)-3-fluoro-1-hydroxy-1-(4-(methylthio)phenyl)propan-2-yl)acetamide was 93%, the reaction selectivity was 98%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0270] Embodiment 104 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 2-(2-chloro-4-(methylthio)-3-((2,2,2-trifluoroethoxy)methyl)benzoyl)cyclohexane-1,3-dione (structural formula: ), other steps and conditions are the same as in Example 1.

[0271] In this example, the conversion rate of 2-(2-chloro-4-(methylthio)-3-((2,2,2-trifluoroethoxy)methyl)benzoyl)cyclohexane-1,3-dione was 93%, the reaction selectivity was 98%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0272] Embodiment 105 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by N-(4-cyano-3-(trifluoromethyl)phenyl)-3-((4-fluorophenyl)thio)-2-hydroxy-2-methylpropionamide (Structural formula: ), other steps and conditions are the same as in Example 1.

[0273] In this example, the conversion rate of N-(4-cyano-3-(trifluoromethyl)phenyl)-3-((4-fluorophenyl)thio)-2-hydroxy-2-methylpropanamide was 95%, the reaction selectivity was 93%, the yield of the target product was 88%, and the Faraday efficiency was 93%.

[0274] Embodiment 106 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 7-chloro-3-methyl-4H-benzo[b][1,4]thiazine (structural formula: ), other steps and conditions are the same as in Example 1.

[0275] In this example, the conversion rate of 7-chloro-3-methyl-4H-benzo[b][1,4]thiazine was 95%, the reaction selectivity was 93%, the yield of the target product was 88%, and the Faraday efficiency was 93%.

[0276] Embodiment 107 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 1-(2-(ethylthio)ethyl)-2-methyl-5-nitro-1H-imidazole (structural formula: ), other steps and conditions are the same as in Example 1.

[0277] In this example, the conversion rate of 1-(2-(ethylthio)ethyl)-2-methyl-5-nitro-1H-imidazole was 91%, the reaction selectivity was 94%, the yield of the target product was 86%, and the Faraday efficiency was 90%.

[0278] Embodiment 108 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 4-(((5-methylisoxazol-3-yl)amino)thio)aniline (structural formula: ), other steps and conditions are the same as in Example 1.

[0279] In this example, the conversion rate of 4-(((5-methylisoxazol-3-yl)amino)thio)aniline was 92%, the reaction selectivity was 97%, the yield of the target product was 89%, and the Faraday efficiency was 93%.

[0280] Embodiment 109 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 2-(aminothio)-N-ethyl-6-methyl-5,6-dihydro-4H-thieno[2,3b]thiopyran-4-amine (structural formula: ), other steps and conditions are the same as in Example 1.

[0281] In this example, the conversion rate of 2-(aminothio)-N-ethyl-6-methyl-5,6-dihydro-4H-thieno[2,3b]thiopyran-4-amine was 94%, the reaction selectivity was 98%, the yield of the target product was 92%, and the Faraday efficiency was 93%.

[0282] Embodiment 110 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by 1-(azacycloheptane-1-yl)-3-(p-tolylthio)urea (structural formula: ), other steps and conditions are the same as in Example 1.

[0283] In this example, the conversion rate of 1-(azepan-1-yl)-3-(p-tolylthio)urea was 94%, the reaction selectivity was 96%, the yield of the target product was 90%, and the Faraday efficiency was 93%.

[0284] Embodiment 111 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced with tetrahydrothiophene (structural formula: ), other steps and conditions are the same as in Example 1.

[0285] In this example, the conversion rate of tetrahydrothiophene is 96%, the reaction selectivity is 96%, the yield of the target product is 92%, and the Faraday efficiency is 93%.

[0286] Embodiment 112 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced by vinyl sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0287] In this example, the conversion rate of vinyl sulfide was 97%, the reaction selectivity was 93%, the yield of the target product was 90%, and the Faraday efficiency was 93%.

[0288] Embodiment 113 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced by ethyl (isopropyl) sulfide (structural formula: ), other steps and conditions are the same as in Example 1.

[0289] In this example, the conversion rate of ethyl (isopropyl) sulfide is 97%, the reaction selectivity is 98%, the yield of the target product is 95%, and the Faraday efficiency is 96%.

[0290] Embodiment 114 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 2-(((3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl)methyl)thio)-1H-benzo[d]imidazole (structural formula: ), other steps and conditions are the same as in Example 1.

[0291] In this example, the conversion rate of ethyl (isopropyl) sulfide is 94%, the reaction selectivity is 98%, the yield of the target product is 92%, and the Faraday efficiency is 94%.

[0292] Embodiment 115 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, the method being different from that described in Example 1, wherein in step (3), dimethyl sulfide is replaced with 2,2-dichloro-N-((1R,2S)-3-fluoro-1-hydroxy-1-(4-(methylthio)phenyl)propan-2-yl)acetamide (structural formula: ), other steps and conditions are the same as in Example 1.

[0293] In this example, the conversion rate of 2,2-dichloro-N-((1R,2S)-3-fluoro-1-hydroxy-1-(4-(methylthio)phenyl)propan-2-yl)acetamide was 96%, the reaction selectivity was 96%, the yield of the target product was 92%, and the Faraday efficiency was 95%.

[0294] Embodiment 116 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide with a high Faraday efficiency heterogeneous catalyst, which is different from that described in Example 1, except that in step (3), dimethyl sulfide is replaced with 2-(diphenylmethylthio)acetamide (structural formula: ), other steps and conditions are the same as in Example 1.

[0295] In this example, the conversion rate of 2-(benzhydrylthio)acetamide was 99%, the reaction selectivity was 99%, the yield of the target product was 98%, and the Faraday efficiency was 97%.

[0296] Embodiment 117 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the voltage is changed to 1.2 V, and the other steps and conditions are the same as those in Example 1.

[0297] In this example, the conversion rate of dimethyl sulfide is 93%, the reaction selectivity is 97%, the yield of the target product is 90%, and the Faraday efficiency is 93%.

[0298] Embodiment 118 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the voltage is changed to 1.5 V, and the other steps and conditions are the same as those in Example 1.

[0299] In this example, the conversion rate of dimethyl sulfide was 94%, the reaction selectivity was 97%, the yield of the target product was 91%, and the Faraday efficiency was 93%.

[0300] Embodiment 119 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (3), the voltage is changed to 1.9 V, and the other steps and conditions are the same as those in Example 1.

[0301] In this example, the conversion rate of dimethyl sulfide was 97%, the reaction selectivity was 95%, the yield of the target product was 92%, and the Faraday efficiency was 95%.

[0302] Embodiment 120 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein: in step (3), the constant voltage mode is changed to a constant current mode, and the current density is 2 mA / cm 2 The catalyst (size 2*10*20 mm) was used as the anode (the anode was immersed in the electrolyte), the platinum sheet was used as the cathode, and no reference electrode was used. The other steps and conditions were the same as in Example 1.

[0303] In this example, the conversion rate of dimethyl sulfide is 98%, the reaction selectivity is 91%, the yield of the target product is 89%, and the Faraday efficiency is 92%.

[0304] Embodiment 121 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein: in step (3), the constant voltage mode is changed to a constant current mode, and the current density is 50 mA / cm 2 The catalyst (size 2*10*20 mm) was used as the anode (the anode was immersed in the electrolyte), the platinum sheet was used as the cathode, and no reference electrode was used. The other steps and conditions were the same as in Example 1.

[0305] In this example, the conversion rate of dimethyl sulfide was 94%, the reaction selectivity was 97%, the yield of the target product was 91%, and the Faraday efficiency was 92%.

[0306] Embodiment 122 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), the constant voltage mode is changed to a constant current mode, and the current density is 100 mA / cm 2 The catalyst (size 2*10*20 mm) was used as the anode (the anode was immersed in the electrolyte), the platinum sheet was used as the cathode, and no reference electrode was used. The other steps and conditions were the same as in Example 1.

[0307] In this example, the conversion rate of dimethyl sulfide was 96%, the reaction selectivity was 96%, the yield of the target product was 92%, and the Faraday efficiency was 94%.

[0308] Embodiment 123 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), the constant voltage mode is changed to a constant current mode, and the current density is 500 mA / cm2 The catalyst (size 2*10*20 mm) was used as the anode (the anode was immersed in the electrolyte), the platinum sheet was used as the cathode, and no reference electrode was used. The other steps and conditions were the same as in Example 1.

[0309] In this example, the conversion rate of dimethyl sulfide is 93%, the reaction selectivity is 94%, the yield of the target product is 87%, and the Faraday efficiency is 89%.

[0310] Embodiment 124 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein in step (3), the constant voltage mode is changed to a constant current mode, and the current density is 1000 mA / cm 2 The catalyst (size 2*10*20 mm) was used as the anode (the anode was immersed in the electrolyte), the platinum sheet was used as the cathode, and no reference electrode was used. The other steps and conditions were the same as in Example 1.

[0311] In this example, the conversion rate of dimethyl sulfide was 97%, the reaction selectivity was 97%, the yield of the target product was 94%, and the Faraday efficiency was 96%.

[0312] Embodiment 125 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, wherein: in step (3), the constant voltage mode is changed to a constant current mode, and the current density is 2000 mA / cm 2 The catalyst (size 2*10*20 mm) was used as the anode (the anode was immersed in the electrolyte), the platinum sheet was used as the cathode, and no reference electrode was used. The other steps and conditions were the same as in Example 1.

[0313] In this example, the conversion rate of dimethyl sulfide was 95%, the reaction selectivity was 91%, the yield of the target product was 86%, and the Faraday efficiency was 87%.

[0314] Embodiment 126 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (1), the concentration of the manganese nitrate aqueous solution is 1.5 mol / L, and the other steps and conditions are the same as those in Example 1.

[0315] In this example, the conversion rate of dimethyl sulfide was 95%, the reaction selectivity was 89%, the yield of the target product was 85%, and the Faraday efficiency was 86%.

[0316] Embodiment 127 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (1), the concentration of the manganese nitrate aqueous solution is 3.3 mol / L, and the other steps and conditions are the same as those in Example 1.

[0317] In this example, the conversion rate of dimethyl sulfide is 96%, the reaction selectivity is 94%, the yield of the target product is 90%, and the Faraday efficiency is 92%.

[0318] Embodiment 128 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, except that in step (1), the current density of the electrochemical deposition is 1 mA / cm 2 , other steps and conditions are the same as in Example 1.

[0319] In this example, the conversion rate of dimethyl sulfide was 93%, the reaction selectivity was 91%, the yield of the target product was 85%, and the Faraday efficiency was 86%.

[0320] Embodiment 129 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, which is different from that described in Example 1, except that in step (1), the current density of the electrochemical deposition is 50 mA / cm 2 , other steps and conditions are the same as in Example 1.

[0321] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 98%, the yield of the target product is 93%, and the Faraday efficiency is 95%.

[0322] Embodiment 130 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (1), the anode is a platinum electrode and the cathode is a nickel plate. The other steps and conditions are the same as those in Example 1.

[0323] In this example, the conversion rate of dimethyl sulfide was 95%, the reaction selectivity was 97%, the yield of the target product was 92%, and the Faraday efficiency was 96%.

[0324] Embodiment 131 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (1), the anode is a carbon cloth and the cathode is a platinum electrode. The other steps and conditions are the same as those in Example 1.

[0325] In this example, the conversion rate of dimethyl sulfide is 95%, the reaction selectivity is 93%, the yield of the target product is 88%, and the Faraday efficiency is 90%.

[0326] Embodiment 132 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency is different from that described in Example 1, except that in step (1), the anode is nickel foam and the cathode is a titanium electrode, and the other steps and conditions are the same as those in Example 1.

[0327] In this example, the conversion rate of dimethyl sulfide is 94%, the reaction selectivity is 98%, the yield of the target product is 92%, and the Faraday efficiency is 94%.

[0328] Comparative Example 1 A method for preparing sulfoxide by electrocatalytic oxidation of sulfide is described in Example 1, except that steps (1) and (2) are omitted, and in step (3), no catalyst is added. The other steps and conditions are the same as those in Example 1.

[0329] In this example, the conversion rate of dimethyl sulfide is 73%, the reaction selectivity is 80%, the yield of the target product is 58%, and the Faraday efficiency is 61%.

[0330] Application Example 1 The method for preparing sulfone using sulfoxide prepared by the method of Example 1 comprises the steps of: The following operation was performed at 25°C. 0.5 mmol (39 mg) of dimethyl sulfoxide, 2*10*20 mm of the catalyst prepared by the method of Example 1 (the catalyst was immersed in the electrolyte, wherein the mass of manganese oxide was 10 wt% of the mass of dimethyl sulfoxide) and 10 mL of water were added to a three-necked flask reactor equipped with a magnetic stirring magnet. Then, sodium nitrate electrolyte (the concentration of electrolyte in water was 0.1 mol / L) was added and mixed thoroughly to form the electrolyte. In an air atmosphere, a silver / silver chloride electrode was used as a reference electrode, a platinum sheet was used as a counter electrode, a constant voltage of 1.7 V was used, and the reaction was carried out at 25°C for 2 hours. After the reaction was completed, the product dimethyl sulfone was obtained by filtration and vacuum drying of the filtrate, with a yield of 98% and a Faraday efficiency of 98% (conversion rate of dimethyl sulfoxide was 99%, and reaction selectivity was 99%).

Claims

1. A method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency, comprising the steps of: The sulfide compound is dissolved in a solvent to obtain an electrolyte; under the action of a metal oxide-coated anode catalyst, an electrocatalytic oxidation reaction is carried out, and the reaction solution is purified to obtain sulfoxide; The solvent is water or a mixed solvent of an organic solvent and water; in the metal oxide coated anode catalyst, the metal in the metal oxide is selected from one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, silver, gold, palladium, platinum, rhodium, iridium, ruthenium, cerium, molybdenum or tungsten; the electrolysis mode used in the electrocatalytic oxidation reaction is constant voltage or constant current; when the electrolysis mode is constant voltage, the counter electrode is a platinum or nickel electrode, the reference electrode is a silver / silver chloride electrode or a saturated calomel electrode, the voltage is 1-1.9 V, and the catalyst is added and immersed in the electrolyte; when the electrolysis mode is constant current, the catalyst is used as the anode, the platinum sheet is used as the cathode, and the current density is 2-2000 mA / cm 2 ; The electrocatalytic oxidation reaction temperature is 25°C-80°C, the reaction time is 5-100h, and the reaction is carried out in an air atmosphere; The preparation method of the metal oxide coated anode catalyst is selected from the following method I or method II: Method I: The preparation method of a metal oxide coated anode catalyst comprises the following steps: mixing a metal salt aqueous solution and a sulfuric acid aqueous solution as an electrolyte, electrochemically depositing the metal oxide on the surface of the anode electrode to obtain an anode coated with a metal oxide precursor; and then calcining to obtain a metal oxide coated anode catalyst; Electrolyte The molar ratio of the metal salt to the sulfuric acid is 0.1-10:1; the temperature of the electrochemical deposition is from room temperature to 80°C, and the current density is 1-50 mA / cm 2 , the electrochemical deposition time is 0.5-5h; the calcination temperature is 300-800℃, the calcination time is 3-6h, the heating rate is 1-10℃ / min, and the calcination atmosphere is air or oxygen; or, Method II: A method for preparing a metal oxide coated anode catalyst comprises the following steps: (1) Route 1: dissolving the manganese source in water, subjecting it to a hydrothermal reaction, and then separating and drying it to obtain manganese oxide; Alternatively, route 2: benzyl alcohol and water are mixed evenly, PVP is added and ultrasonicated to form an emulsion, and a manganese source aqueous solution is added dropwise under stirring, reacted, separated, and dried to obtain manganese oxide; (2) Manganese oxide, conductive agent and binder are fully dispersed in an organic solvent, then coated on the surface of the anode material, and dried to obtain a metal oxide-coated anode catalyst.

2. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency according to claim 1, characterized in that: The thioether compound is selected from one of the following compounds: 。 3. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst according to claim 1, characterized in that: Includes one or more of the following conditions: i. In a mixed solvent of an organic solvent and water, the organic solvent is acetonitrile, acetone, ethanol, methanol, toluene, dichloromethane, chloroform, chlorobenzene, DMF, DMA, dioxane, NMP, ether, tetrahydrofuran, butanol, xylene, isopropanol, ethylene glycol or triethylamine; the mass ratio of the organic solvent to water is 0.25-9:1; ii. The concentration of the thioether compound in the solvent is 1-800 mmol / L; iii. The electrolyte also includes an electrolyte; the electrolyte is selected from lithium perchlorate, lithium hexafluorophosphate, sodium chloride, potassium chloride, ammonium chloride, lithium sulfate, lithium nitrate, lithium carbonate, lithium chloride, sodium sulfate, potassium sulfate, ammonium sulfate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium nitrate, potassium nitrate, ammonium nitrate, tetramethylammonium tetrafluoroborate, tetraethylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, tetramethylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, tetramethylammonium acetate, tetraethylammonium acetate, tetrabutylammonium acetate, tetramethyl The electrolyte is selected from the group consisting of tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrabutylammonium fluoride, tetramethylammonium hydrogen sulfate, tetraethylammonium hydrogen sulfate, tetrabutylammonium hydrogen sulfate, tetramethylammonium hydrogen carbonate, tetraethylammonium hydrogen carbonate, tetrabutylammonium hydrogen carbonate, tetramethylammonium perchlorate, tetraethylammonium perchlorate, tetrabutylammonium perchlorate, tetramethylammonium nitrate, tetraethylammonium nitrate and tetrabutylammonium nitrate; and the concentration of the electrolyte in the solvent is 0.1-1 mol / L.

4. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency according to claim 1, characterized in that: Includes one or more of the following conditions: i. The mass of the metal oxide in the metal oxide-coated anode catalyst is 1 wt%-40 wt% of the mass of the sulfide compound; ii. The anode in the metal oxide coated anode catalyst is selected from one of a titanium electrode, a platinum electrode, a platinum-titanium electrode, a carbon cloth, a carbon paper, a carbon felt, a carbon fiber, a nickel foam or a nickel plate.

5. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst according to claim 1, characterized in that: Method I of the method for preparing a metal oxide coated anode catalyst includes one or more of the following conditions: i. The metal salt is a metal sulfate, a metal nitrate or a metal hydrochloride; ii. The metal in the metal salt is selected from one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, silver, gold, palladium, platinum, rhodium, iridium, ruthenium, cerium, molybdenum or tungsten; iii. The concentration of the metal salt aqueous solution is 0.1-4 mol / L; the concentration of the sulfuric acid aqueous solution is 0.1-2 mol / L.

6. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency according to claim 1, characterized in that: In method I of the preparation method of the metal oxide coated anode catalyst, the metal salt is selected from titanium sulfate, titanium nitrate, titanium chloride, vanadium sulfate, vanadium nitrate, vanadium chloride, chromium sulfate, chromium nitrate, chromium chloride, potassium dichromate, manganese sulfate, manganese nitrate, manganese chloride, ferric sulfate, ferrous sulfate, ferric nitrate, ferrous nitrate, ferric chloride, ferrous chloride, cobalt sulfate, cobalt nitrate, cobalt chloride, nickel sulfate, nickel nitrate, nickel chloride, copper sulfate, copper nitrate, copper chloride, silver sulfate, silver nitrate, silver chloride, gold nitrate, gold chloride, palladium sulfate, palladium nitrate, palladium chloride, platinum sulfite, platinum nitrate, platinum chloride, platinum dichloride, chloroplatinic acid, rhodium sulfate, rhodium nitrate, rhodium chloride, iridium chloride, iridium tetrachloride, molybdenum sulfate, molybdenum nitrate, molybdenum chloride, ammonium molybdate, ruthenium sulfate, ruthenium nitrate, ruthenium chloride, cerium sulfate, cerium nitrate, cerium chloride or tungsten nitrate.

7. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst according to claim 1, characterized in that: In method I of the preparation method of metal oxide-coated anode catalyst, the anode used for electrochemical deposition is selected from one of platinum-titanium electrode, platinum electrode, titanium electrode, carbon cloth, carbon paper, carbon felt, carbon fiber, nickel foam or nickel plate; the cathode used is selected from one of carbon plate, carbon cloth, carbon paper, carbon fiber, carbon felt, platinum electrode, platinum-titanium electrode, titanium electrode, nickel plate or nickel foam.

8. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a high Faraday efficiency heterogeneous catalyst according to claim 1, characterized in that: In method II of the preparation method of metal oxide coated anode catalyst, in step (1) route 1, the manganese source is one or a combination of KMnO4 or MnSO4, and the volume ratio of the molar amount of the manganese source to water is 0.2-1 mol / L; in step (1) route 1, the hydrothermal reaction temperature is 150-170°C, and the hydrothermal reaction time is 6-12h; in step (1) route 1, a hydrochloric acid aqueous solution with a mass concentration of 30-37% is added to the reaction, and the volume ratio of the hydrochloric acid aqueous solution to water is 1:120-170.

9. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency according to claim 1, characterized in that: In method II of the preparation method of metal oxide coated anode catalyst, in step (1) route 2, the volume ratio of benzyl alcohol to water is 1:5-10, the mass ratio of PVP to benzyl alcohol is 5-15 mg / mL, the manganese source is KMnO4, the concentration of the manganese source aqueous solution is 0.05-1 mol / L, and the volume ratio of the manganese source aqueous solution to benzyl alcohol is 2-4:1; in step (1) route 2, the reaction temperature is room temperature and the reaction time is 1-5 h.

10. The method for preparing sulfoxide by electrocatalytic oxidation of sulfide using a heterogeneous catalyst with high Faraday efficiency according to claim 1, characterized in that: In method II of the preparation method of metal oxide coated anode catalyst, in step (2), the conductive agent is carbon black, the binder is polyvinylidene fluoride (PVDF), the organic solvent is N-methylpyrrolidone, and the mass ratio of manganese oxide, conductive agent and binder is 1-5:1:2-8.

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