A selenium-doped titanium dioxide-loaded manganese photocatalyst and its use

Abstract

The present invention discloses a selenium-doped titanium dioxide-loaded manganese photocatalyst in the field of chemical technology and its use. The photocatalyst is prepared by mixing an ethanol solution of tetrabutyl titanate with an HCl solution of manganese chloride and stirring and aging at room temperature; filtering, washing, and drying to obtain a filter cake; then grinding and mixing the obtained filter cake with selenium powder and a long-chain carboxylate additive to obtain a mixture; and finally calcining the mixture to obtain a selenium-doped titanium dioxide-loaded manganese photocatalyst. The photocatalyst can catalytically oxidize to obtain vinyl sulfate. The prepared vinyl sulfate product is easy to separate and purify and does not pollute the environment. The catalyst preparation process of the present invention is simple and does not require the use of precious metals, thereby achieving higher economic value at a lower cost and is expected to be widely promoted and applied in industry.

Description

Technical Field

[0001] The invention relates to the technical fields of material chemistry and catalytic chemistry, and relates to a selenium-doped titanium dioxide-loaded manganese photocatalyst and application thereof. Background Art

[0002] Vinyl sulfate is an important lithium battery additive with promising market prospects. The mainstream method for synthesizing vinyl sulfate is through the oxidation of vinyl sulfite. However, existing technologies typically require the use of a ruthenium catalyst and sodium hypochlorite as an oxidant. Ruthenium is expensive, and the sodium hypochlorite reaction produces sodium chloride (industrial waste salt), which increases solid waste disposal costs. Therefore, developing a new, cheaper and more environmentally friendly synthesis method has great application value.

[0003] Heterogeneous photocatalytic organic synthesis is a potential and ideal "clean" chemical production technology. It utilizes light energy as a driving force and can achieve good conversion rates and selectivity even under relatively mild conditions. Titanium dioxide, as an excellent semiconductor, possesses excellent photocatalytic properties. It is also an excellent catalyst support. Doping and loading titanium dioxide with other elements can modify the band edge and band gap energies, thereby promoting photon absorption and enhancing its photocatalytic performance. However, there is no record of the use of photocatalysts to synthesize vinyl sulfate in the prior art. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a selenium-doped titanium dioxide-loaded manganese photocatalyst and its use, so that it can be used to efficiently catalyze the oxidation reaction of vinyl sulfite. By loading manganese with titanium dioxide and doping it with selenium, the photocatalytic performance of titanium dioxide can be improved, and higher economic value can be achieved at a lower cost and in a green way.

[0005] To this end, the technical solution of the present invention is as follows: a selenium-doped titanium dioxide-loaded manganese photocatalyst, the preparation method of which comprises the following steps:

[0006] (1) Tetrabutyl titanate and anhydrous ethanol were mixed evenly to prepare solution A; manganese chloride and HCl solution were mixed evenly to prepare solution B;

[0007] (2) Add solution B dropwise to solution A, and stir and age at room temperature after the addition is complete;

[0008] (3) The obtained solution is filtered, washed, and dried to obtain a filter cake C, and the obtained filter cake C is ground and mixed with selenium powder and a long-chain carboxylate additive to obtain a mixture D;

[0009] (4) The mixture D is placed in a tubular furnace and calcined to obtain a selenium-doped titanium dioxide-loaded manganese photocatalyst (Se-MnO2 / TiO2).

[0010] Furthermore, the volume content of tetrabutyl titanate in Solution A is 5-35%. During the hydrolysis preparation of titanium dioxide, the concentration of tetrabutyl titanate cannot be too high, otherwise the titanium dioxide will form lumps and become undispersible, affecting catalytic performance. The volume ratio of tetrabutyl titanate to anhydrous ethanol is preferably 1:3 (tetrabutyl titanate content is 25% by volume).

[0011] Furthermore, in the HCl solution, the concentration of HCL is 0.05~0.15 mol / L, and in solution B, the concentration of manganese chloride is 0.25~2.25 g / L (0.002~0.018 mol / L); the concentration of manganese chloride should not be too high. Too high a concentration will cause more manganese to adhere to the surface of titanium dioxide, which will reduce the absorption efficiency of titanium dioxide to photons. The preferred dosage is 1.26 g / L (0.01 mol / L).

[0012] Furthermore, the ratio of tetrabutyl titanate to MnCl2 is 10 mL: (0.025-0.225) g.

[0013] Furthermore, the mass of selenium powder added is 1-20% of the filter cake C.

[0014] Furthermore, the long-chain carboxylate additive includes one of ammonium oleate, sodium stearate, potassium stearate, ammonium stearate and lithium stearate, and the amount used is 0.1-0.8% of the mass of the filter cake C.

[0015] Furthermore, in step (4), the mixture D is calcined at a temperature of 450-600° C. for 1-3 hours.

[0016] The present invention also provides a use of a selenium-doped titanium dioxide-loaded manganese photocatalyst, specifically: under light conditions, using a selenium-doped titanium dioxide-loaded manganese photocatalyst to catalyze the oxidation of vinyl sulfite in an oxygen environment to prepare vinyl sulfate at room temperature.

[0017] Furthermore, the light wavelength of the catalytic oxidation reaction illumination condition is 375~520 nm.

[0018] Furthermore, the solvent used in the oxidation reaction is an aqueous solution of ethyl acetate containing 60-90% ethyl acetate by volume; the initial concentration of the reactant vinyl sulfite is 0.1-1.0 mol / L, and the ratio of the selenium-doped titanium dioxide-supported manganese photocatalyst to the reactant vinyl sulfite is (5-40) mg:1 mmol, preferably 20 mg:1 mmol.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The titanium dioxide used in the present invention has good environmental stability and photocatalytic performance and is easy to synthesize, so it can be used in industry.

[0021] 2. In the present invention, manganese and selenium are used to promote titanium dioxide's absorption of photons and improve its photocatalytic performance.

[0022] 3. Calcination can remove organic matter and other impurities in the material. During this process, a porous structure is formed in the catalyst, thereby increasing the specific surface area of ​​the catalyst, which is conducive to contact with the reactants.

[0023] 4. The catalyst prepared by this invention does not require the addition of expensive metals to enhance its oxidation performance, and the preparation process is simple, thereby achieving higher economic value at a lower cost. The entire material synthesis process is simple and inexpensive, and is expected to be widely promoted and applied in industry.

[0024] 5. The prepared photocatalyst can efficiently oxidize vinyl sulfite to prepare vinyl sulfate, providing a new technical route for the preparation of this lithium battery raw material.

[0025] 6. In the oxidation reaction of vinyl sulfite, the amount of selenium-doped titanium dioxide-supported manganese photocatalyst used ensures sufficient contact between the catalyst and reactants in the reaction system and their dispersion within the reaction solution. This effectively absorbs light, effectively utilizing light energy and significantly enhancing catalytic activity. The oxidation reaction can be carried out under mild and environmentally friendly conditions.

[0026] 7. During catalyst preparation, long-chain carboxylates are added as additives. Carboxylic acids release carbon dioxide during high-temperature calcination. The resulting bubbles facilitate the full bonding and dispersion of selenium within the catalyst matrix, thereby increasing catalytic site utilization and enhancing catalytic activity, enabling the catalyst to catalyze the oxidation of difficult-to-oxidize molecules. Lithium stearate is the most effective. Sodium stearate offers the best value for money due to its low cost.

[0027] The present invention uses titanium dioxide as a catalyst carrier, loads manganese and dopes selenium into it to improve its photocatalytic performance, and prepares a selenium-doped titanium dioxide-loaded manganese photocatalyst (Se-MnO2 / TiO2). The use of this catalyst can catalyze the oxidation reaction of vinyl sulfite under mild and green conditions. The catalyst dosage is only 8-18% of the weight of the raw material. Compared with traditional photocatalytic materials, the catalyst prepared by the present invention does not need to be doped with expensive metals to enhance its oxidation performance, and the preparation process is simple, thereby achieving higher economic value at a lower cost. The entire material synthesis process is simple and inexpensive, and is expected to be widely promoted and applied in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1This is a scanning electron microscope image of Se-MnO2 / TiO2 prepared in Example 1;

[0029] Figure 2 This is a scanning electron microscope image of MnO2 / TiO2 prepared in comparative example.

[0030] Figure 3 This is the transmission electron microscope image of Se-MnO2 / TiO2 prepared in Example 1.

[0031] Figure 4 This is a high-resolution transmission electron microscopy image of Se-MnO2 / TiO2 prepared in Example 1.

[0032] Figure 5 This is the electron diffraction pattern of Se-MnO2 / TiO2 prepared in Example 1.

[0033] Figure 6 This is the energy dispersive X-ray spectrum (EDX) of Se-MnO2 / TiO2 prepared in Example 1. DETAILED DESCRIPTION Example 1

[0034] 1. Preparation of Se-MnO2 / TiO2 catalyst:

[0035] The sources and purity of the drugs used are as follows:

[0036] Tetrabutyl titanate (CAS No.: 5593-70-4) was purchased from Anaiji with a purity of 99%.

[0037] Hydrochloric acid (CAS No. 7647-01-0) was purchased from Sinopharm Group with a concentration of 36%~38%.

[0038] Manganese chloride (CAS No. 7773-01-5) was purchased from Anaiji with a purity of 99%.

[0039] Selenium powder (CAS No. 7782-49-2) was purchased from Anaiji with a purity of 99%.

[0040] Anhydrous ethanol (CAS No.: 64-17-5) was purchased from Aladdin with a purity of 99.5%.

[0041] The preparation steps are as follows:

[0042] (1) Tetrabutyl titanate and anhydrous ethanol were mixed evenly in a volume ratio of 1:3 (the volume content of tetrabutyl titanate was 25%) to prepare solution A; manganese chloride was mixed evenly with HCl solution to prepare solution B; wherein the concentration of HCl was 0.1 mol / L, and the concentration of manganese chloride in solution B was 1.26 g / L (0.01 mol / L).

[0043] (2) Take 100 ml of solution B and add it dropwise to 40 ml of solution A. At this time, the ratio of tetrabutyl titanate to MnCl2 is 10 ml: 0.126 g. After the addition is completed, stir and age at room temperature for 0.5-4 hours to obtain titanium dioxide sol.

[0044] (3) The resulting solution is filtered, washed, and dried at 40-100°C for 2-6 hours to obtain filter cake C. After grinding into powder, selenium powder is added thereto, with the mass of the added selenium powder being 10% of the mass of the filter cake. Sodium stearate is also added to adjust the catalyst. Sodium stearate can be replaced by any of ammonium oleate, potassium stearate, and ammonium stearate, with the amount of the additive being 0.4% of the mass of the filter cake. The mixture is ground and mixed uniformly to obtain mixture D.

[0045] (4) Place the mixture D in a tube furnace and calcine it at 500 °C for 2 h to obtain the selenium-doped titanium dioxide-loaded manganese photocatalyst (Se-MnO2 / TiO2). Comparative Example

[0046] The preparation method is the same as that of Example 1, except that no selenium powder is added to the dried filter cake, and the MnO2 / TiO2 catalyst is obtained by calcining the filter cake at 500°C for 2 hours after grinding.

[0047] 2. Material Characterization

[0048] Scanning electron microscopy (SEM) was performed on the Se-MnO2 / TiO2 catalyst prepared in Example 1 and the MnO2 / TiO2 catalyst prepared in the comparative example to observe their microscopic morphology. It was found that the Se-MnO2 / TiO2 catalyst was formed by a block carrier supporting a tiny granular structure, such as Figure 1 As shown; MnO2 / TiO2 catalyst is formed by the accumulation of large pieces of sheet structures, such as Figure 2 As shown in Figure 2, doping with selenium is beneficial for the formation of more pores on the catalyst surface to provide active sites and prevent material clustering. Figure 3 The transmission electron microscopy (TEM) images show that the Se-MnO2 / TiO2 catalyst has a block structure. Figure 4 Lattice fringes can be observed in the high-resolution transmission electron microscopy (HR-TEM) image shown, and the crystal is anatase structure and ruby ​​structure of titanium dioxide crystal. Figure 5 The electron diffraction pattern shown further confirms that there is a crystalline structure in the material. Figure 6 Energy-dispersive X-ray spectroscopy (EDX) shown confirms the successful loading of selenium and manganese, while titanium was also observed on the titanium dioxide.

[0049] 3. Application

[0050] The Se-MnO2 / TiO2 catalyst prepared in Example 1 was applied to the oxidation reaction of vinyl sulfite to test the photocatalytic performance of the Se-MnO2 / TiO2 catalyst.

[0051] 1 mmol of ethylene sulfite, 90% ethyl acetate (volume content, the balance 10% being water), and Se-MnO2 / TiO2 were placed in a reaction vessel. The initial concentration of the ethylene sulfite reactant was 0.5 mol / L, and the ratio of the selenium-doped titanium dioxide-supported manganese photocatalyst to the ethylene sulfite reactant was 20 mg:1 mmol. After sealing, the vessel was magnetically stirred under 395 nm violet light for 24 hours. Oxygen generated by water decomposition provided the oxygen source for the oxidation reaction. The product was isolated by high-performance liquid chromatography with a yield of 76%.

[0052] Further experiments showed that the initial concentration of the reactant vinyl sulfite can be selected between 0.1 and 1.0 mol / L, and when the ratio of the selenium-doped titanium dioxide-loaded manganese photocatalyst to the reactant vinyl sulfite is selected in the range of (5 to 40) mg: 1 mmol, the reaction yield is greater than 50%.

[0053] For comparison, the MnO2 / TiO2 prepared in the comparative example was used to catalyze the reaction, and the yield was calculated to be 15% after 24 hours of reaction. The above results indicate that selenium doping of titanium dioxide can significantly enhance the photocatalytic activity of the catalyst. Example 2

[0054] The specific implementation method is the same as that of Example 1, except that the concentration of tetrabutyl titanate is changed during the catalyst preparation process. The comparison results are shown in Table 1.

[0055] Table 1 Effect of tetrabutyl titanate concentration on oxidation yield of ethylene sulfite

[0056] serial number concentration Yield (%) 1 5% trance 2 10% 16 3 12% 25 4 15% 36 5 18% 47 6 20% 58 7 23% 68 8 25% 76 9 28% 76 10 30% 78 11 32% 77 12 35% 77 13 40% 78 14 45% 78

[0057] As shown in the table above, the yield of oxidation products increases linearly when using catalysts prepared with tetrabutyl titanate concentrations ranging from 5% to 25% by volume, reaching 58% at 20%. When using a catalyst prepared with a tetrabutyl titanate concentration of 25% by volume, the yield of vinyl sulfite oxidation reaches a peak of 76%. When the tetrabutyl titanate concentration exceeds 25%, the yield of vinyl sulfite oxidation does not increase significantly. Therefore, the optimal value is 25%. At this point, the volume ratio of tetrabutyl titanate to anhydrous ethanol is 1:3 (tetrabutyl titanate content is 25% by volume). The optimal volume content of tetrabutyl titanate is 20-35%. Example 3

[0058] The specific implementation method is the same as that of Example 1, except that the concentration of manganese chloride is changed during the catalyst preparation process. The comparison results are shown in Table 2.

[0059] Table 2 Effect of manganese chloride concentration on oxidation yield of ethylene sulfite

[0060] serial number Concentration (g / L) Yield (%) 1 0.10 18 2 0.15 30 3 0.20 42 4 0.25 55 5 0.75 65 6 1.26 76 7 1.75 70 8 2.25 58 9 2.50 46 10 3.00 40

[0061] As shown in the table above, the catalyst prepared using 1.26 g / L (0.01) manganese chloride has the highest yield for ethylene sulfite oxidation. Furthermore, when the concentration exceeds 1.26 g / L, the yield decreases. The acceptable range is 0.25-2.25 g / L. Example 4

[0062] The specific implementation method is the same as that of Example 1, except that the concentration of HCl is changed during the catalyst preparation process. The comparison results are shown in Table 3.

[0063] Table 3 Effect of HCl concentration on oxidation yield of ethylene sulfite

[0064] serial number Concentration (mol / L) Yield (%) 1 0.03 43 2 0.05 58 3 0.1 76 4 0.15 55 5 0.2 40 6 0.25 38

[0065] It can be seen from the above table that when the HCl concentration is 0.1 mol / L, the oxidation yield of ethylene sulfite is the highest. Increasing the HCl concentration will reduce the oxidation yield of ethylene sulfite. Example 5

[0066] The specific implementation method is the same as Example 1, except that the proportion of selenium powder added to the catalyst during preparation is changed. The results are shown in Table 4.

[0067] Table 4 Effect of different amounts of selenium powder on the oxidation yield of ethylene sulfite

[0068] serial number Mass fraction (%) Yield (%) 1 1 58 2 5 66 3 10 76 4 15 78 5 20 75

[0069] As can be seen from the above table, as the mass fraction of selenium powder increases, the yield of ethylene sulfite oxidation also increases. However, when the mass fraction is greater than 10%, the oxidation yield of ethylene sulfite does not change significantly. We believe that the best selenium powder dosage is 10%. Example 6

[0070] The specific implementation method is the same as Example 1, except that the long-chain carboxylate added during the catalyst preparation process is changed. The results are shown in Table 5.

[0071] Table 5 Effect of different long-chain carboxylates on the oxidation yield of ethylene sulfite

[0072] serial number Long-chain carboxylates Yield (%) 1 Sodium oleate 36 2 Potassium oleate 45 3 Ammonium oleate 50 4 Sodium stearate 76 5 Potassium stearate 55 6 Ammonium stearate 62 7 lithium stearate 78

[0073] As shown in the table above, sodium stearate offers high yields in the oxidation of ethylene sulfite, and sodium stearate is low-cost, offering the best value for money. Sodium oleate and potassium oleate offer lower yields and are therefore undesirable. Carboxylic acids release carbon dioxide during high-temperature calcination. The bubbling of these bubbles facilitates the thorough bonding and dispersion of selenium within the catalyst matrix, thereby increasing catalytic site utilization and enhancing catalytic activity. This allows the catalyst to oxidize difficult-to-oxidize molecules. However, due to the double bonds contained in oleate, it oxidizes at high temperatures, producing complex diols that react with selenium oxides to form esters, weakening catalytic activity. Furthermore, the alkalinity of the cation also influences catalytic activity; weaker alkalinity results in higher activity. Lithium stearate is the most effective, but the high cost of lithium salts and the limited improvement in performance make it cost-prohibitive. Ammonium stearate also decomposes at 110°C, thus affecting activity. Example 7

[0074] The specific implementation method is the same as Example 1, except that the amount of sodium stearate added to the catalyst during preparation is changed. The results are shown in Table 6.

[0075] Table 6 Effect of different amounts of sodium stearate on the oxidation yield of ethylene sulfite

[0076] serial number Mass fraction (%) Yield (%) 1 0.1 40 2 0.2 64 3 0.4 76 4 0.6 72 5 0.8 77 6 0 0

[0077] As shown in the table above, the yield of ethylene sulfite oxidation increases with increasing sodium stearate concentration. However, when the concentration exceeds 0.4%, the yield of ethylene sulfite oxidation does not change significantly. We believe that a selenium powder dosage of 0.4% is optimal. Without sodium stearate, the catalytic activity is completely absent, indicating that the oxidation of sulfite to sulfate is difficult and that common catalysts are ineffective (Table 6, No. 6). Example 8

[0078] The specific implementation method is the same as Example 1, except that the temperature and time of calcining the catalyst are changed. The results are shown in Table 7.

[0079] Table 7 Effect of calcining catalyst at different temperatures and times on the oxidation yield of ethylene sulfite

[0080] serial number Temperature (℃) Time (h) Yield (%) 1 450 2 69 2 500 2 76 3 550 2 72 4 600 2 70 5 500 1 69 6 500 3 76

[0081] It can be seen from the above table that the most suitable temperature for calcining the catalyst is 500°C, and the best calcining time is 2 h. Continuing to extend the calcining time will not increase the yield of vinyl sulfite oxidation. Example 9

[0082] The specific implementation method is the same as Example 1, except that the solvent used in the reaction system is changed. The results are shown in Table 8.

[0083] Table 8 Effect of different solvents on the oxidation yield of ethylene sulfite

[0084] serial number Solvent (volume ratio, the rest is water) Dosage (ml) Yield (%) 1 90% ethyl acetate 2 76 2 90% dimethyl carbonate 2 <5 3 90% diethyl carbonate 2 <5 4 60% ethyl acetate 2 58 5 30% ethyl acetate 2 36 6 99% ethyl acetate 2 <5

[0085] As shown in the table above, the yield of ethylene sulfite oxidation is highest when using a 90% ethyl acetate solution, reaching 76%. As the water content in the solution increases, the yield of ethylene sulfite oxidation gradually decreases. Using high-purity ethyl acetate as the solvent also produces virtually no product. When the ethyl acetate content exceeds 90%, the yield drops sharply. This indicates that the reaction is suitable for conducting in an aqueous ester phase solution. Water decomposition provides an oxygen source for the reaction. The volume content of ethyl acetate in the aqueous ethyl acetate solution is preferably 60-90%. Example 10

[0086] The specific implementation method is the same as Example 1, except that the light intensity and wavelength used in the reaction system are changed. The results are shown in Table 9.

[0087] Table 9 Effects of different light intensities and wavelengths on the oxidation yield of ethylene sulfite during the reaction

[0088] serial number Strength (W) Wavelength (nm) Yield (%) 1 60 395 63 2 60 455 trance 3 60 520 trance 4 40 395 56 6 80 395 76 7 100 395 74

[0089] As can be seen from the above table, the yield of ethylene sulfite oxidation is the highest under irradiation with a wavelength of 395 nm, and as the light intensity increases, the reaction yield also increases. When the light intensity exceeds 80 W, it has little effect on the reaction yield.

[0090] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features therein according to the disclosed technical content without creative labor, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. A selenium-doped titanium dioxide-loaded manganese photocatalyst, the preparation method of which comprises the following steps: (1) Tetrabutyl titanate and anhydrous ethanol were mixed evenly to prepare solution A; manganese chloride and HCl solution were mixed evenly to prepare solution B; (2) Add solution B dropwise to solution A, and stir and age at room temperature after the addition is complete; (3) The obtained solution is filtered, washed, and dried to obtain a filter cake C, and the obtained filter cake C is ground and mixed with selenium powder and a long-chain carboxylate additive to obtain a mixture D; (4) The mixture D is placed in a tubular furnace and calcined to obtain a selenium-doped titanium dioxide-loaded manganese photocatalyst.

2. The selenium-doped titanium dioxide-loaded manganese photocatalyst according to claim 1, characterized in that: In the solution A, the volume content of tetrabutyl titanate is 20-35%.

3. The selenium-doped titanium dioxide-loaded manganese photocatalyst according to claim 1, characterized in that: In the HCl solution, the concentration of HCl is 0.05-0.15 mol / L, and in solution B, the concentration of manganese chloride is 0.25-2.25 g / L.

4. The selenium-doped titanium dioxide-loaded manganese photocatalyst according to claim 1, characterized in that: The ratio of tetrabutyl titanate to MnCl2 is 10 mL: (0.025-0.225) g.

5. The selenium-doped titanium dioxide-loaded manganese photocatalyst according to claim 1, characterized in that: The mass of added selenium powder is 1~20% of filter cake C.

6. The selenium-doped titanium dioxide-loaded manganese photocatalyst according to claim 1, characterized in that: The long-chain carboxylate additive includes one of ammonium oleate, sodium stearate, potassium stearate, ammonium stearate and lithium stearate, and the amount used is 0.1-0.8% of the mass of the filter cake C.

7. The selenium-doped titanium dioxide-loaded manganese photocatalyst according to claim 1, characterized in that: In step (4), the mixture D is calcined at a temperature of 450-600° C. for 1-3 hours.

8. Use of the selenium-doped titanium dioxide-supported manganese photocatalyst according to any one of claims 1 to 7, characterized in that: Under light conditions, selenium-doped titanium dioxide-loaded manganese photocatalyst is used to catalyze the oxidation of vinyl sulfite in an oxygen environment to prepare vinyl sulfate at room temperature.

9. The use of the selenium-doped titanium dioxide-supported manganese photocatalyst according to claim 8, characterized in that: The wavelength of light for the catalytic oxidation reaction is 375~520 nm.

10. The use of the selenium-doped titanium dioxide-loaded manganese photocatalyst according to claim 8, characterized in that: The solvent used in the oxidation reaction is an ethyl acetate aqueous solution with a volume content of 60-90% ethyl acetate; the initial concentration of the reactant vinyl sulfite is 0.1-1.0 mol / L, and the ratio of the selenium-doped titanium dioxide-loaded manganese photocatalyst to the reactant vinyl sulfite is (5-40) mg:1 mmol.

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