Titanium-based catalyst, its preparation method and synthesis method of oxasulfuron

Abstract

The present invention provides a titanium-based catalyst, a preparation method thereof, and a method for synthesizing oxasulfuron. The titanium-based catalyst includes: a main active component and a promoter metal component M doped in the main active component; wherein, the main active component is titanium dioxide nanobelts, and the titanium dioxide nanobelts form oxygen vacancy defects, and the concentration of the oxygen vacancy defects is 5-20 μmol / g; the promoter metal component M includes at least one of Re, Ru, Mo, V, Ce, Zn, and Cr. The above titanium-based catalyst is loaded in a fixed bed and used in the reaction for synthesizing oxasulfuron by sulfide oxidation. The oxygen vacancy defect sites can not only enhance the adsorption and activation of reactants, thereby improving the reaction kinetics of the oxidation process, but also can have an electronic interaction with the promoter metal ions, improving the dispersion and stability of the promoter metal component M on the titanium dioxide nanobelts, and further providing more reaction active sites, realizing the continuous synthesis of oxasulfuron.

Description

Technical Field

[0001] The present invention relates to the field of chemical engineering technology, and in particular, to a titanium-based catalyst, a preparation method thereof, and a synthesis method of pyroxasulfone. Background Art

[0002] Pyroxasulfone, molecular formula: C 12 H 14 F 5 N 3 O 4 S, molecular weight: 391.31, chemical name: 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)methylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole. The structural formula of this compound is shown as follows:

[0003]

[0004] Pyroxasulfone is an isoxazole herbicide and has the effect of inhibiting plant cell division. This herbicide was first discovered by the K-I Chemical Research Institute in Japan and later industrialized jointly by the Nippon Soda Co., Ltd. and the Ayhara Chemical Co., Ltd. in Japan. Pyroxasulfone is a broad-spectrum herbicide and can be used as a pre-emergence soil treatment agent for most crop fields. Its mechanism of action is similar to that of acetochlor and metolachlor herbicides. After application, it is absorbed by the young roots and buds of weeds, inhibits the early growth of seedlings, destroys the meristem and coleoptile, and is a serious potential inhibitor in the biosynthesis of very long chain fatty acids (VLCFA) (C20 - C30) in plants. It has the advantages of high biological activity, low application rate per unit area, and long herbicidal duration.

[0005] The synthesis of pyroxasulfone involves multiple steps, and the oxidation of thioether to sulfone is the key step of the reaction and also a hot spot and difficulty in research. Currently, the selective oxidation of thioether to sulfone is usually carried out in a batch reactor using a homogeneous tungsten catalyst or molybdenum catalyst, often accompanied by the generation of by-products such as sulfoxide and peroxide impurities. Among them, how to control the high-selectivity oxidation of thioether to sulfone is the key point in the synthesis of this reaction.

[0006] The existing catalysts for the oxidation synthesis of pyraclonil from thioether (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) mainly focus on tungsten, molybdenum or niobium catalysts, especially tungsten catalysts (such as tungstic acid, tungstates (sodium tungstate, sodium tungstate dihydrate, etc.), tungsten oxide, phosphotungstic acid and its salts, etc.). However, there are several problems with such catalysts: 1. Tungsten, molybdenum and niobium catalysts are expensive (especially tungsten and niobium catalysts), and the existing technologies can only be used for batch kettle oxidation reactions, and do not have the conditions for continuous production of pyraclonil; 2. The batch reaction cycle is long, the catalyst recovery is difficult, the active components are easily lost, and it is difficult to reuse, the catalyst usage cost is high, and the product separation and purification increase additional investment; 3. Most of the existing catalysts are bulk structures, with large particle sizes, few exposed active metal atoms, low catalyst active surface area, which is not conducive to the adsorption and activation of reactants, resulting in slow kinetics of thioether oxidation reaction; 4. The reaction system generally contains acidic substances such as sulfuric acid and hydrochloric acid, and general supported catalysts (such as alumina as the carrier) are difficult to meet the requirements of long-term fixed-bed production.

[0007] In view of this, the present application is specifically proposed. Summary of the Invention

[0008] The main object of the present invention is to provide a titanium-based catalyst, its preparation method and a method for synthesizing pyraclonil, so as to solve the problems in the prior art that tungsten catalysts, molybdenum catalysts or niobium catalysts as catalysts for synthesizing pyraclonil have at least one of the problems of high cost, inability to continuously produce pyraclonil, long reaction cycle, high post-treatment cost, slow reaction kinetics, difficulty in long-term production in a fixed bed, poor catalytic activity and low reaction selectivity.

[0009] To achieve the above object, according to one aspect of the present invention, a titanium-based catalyst is provided, including: a main active component and a promoter metal component M doped in the main active component; wherein, the main active component is titanium dioxide nanoribbons, and the titanium dioxide nanoribbons form oxygen vacancy defects, and the concentration of the oxygen vacancy defects is 5-20 μmol / g; the promoter metal component M includes at least one of Re, Ru, Mo, V, Ce, Zn and Cr.

[0010] Furthermore, the mass ratio of the promoter metal component M to the titanium dioxide nanoribbons is 0.5-5:100.

[0011] Furthermore, the titanium dioxide nanoribbons are nanoribbon-shaped, and their thickness is 1-5 nm.

[0012] According to another aspect of the present invention, there is provided a method for preparing the titanium-based catalyst provided in the first aspect above, and the preparation method includes the following steps: Step S1, preparing titanium dioxide nanoribbons with oxygen vacancy defects; Step S2, mixing the titanium dioxide nanoribbons, M source and water, and then performing first drying and first calcination in sequence to obtain the titanium-based catalyst.

[0013] Further, Step S1 includes: Step S11, mixing a titanium source and an alkaline solution, performing a hydrothermal reaction to obtain a titanate; Step S12, mixing the titanate, an alcohol and an acidic solution for ion exchange to obtain titanium acid nanoribbons; Step S13, washing and performing second drying on the titanium acid nanoribbons in sequence to obtain a titanium dioxide nanoribbon precursor; Step S14, performing second calcination on the titanium dioxide nanoribbon precursor to obtain titanium dioxide nanoribbons.

[0014] Further, in Step S11, the titanium source is at least one of titanium dioxide, titanium oxysulfate and P25 titanium dioxide;

[0015] and / or, the alkaline solution includes a sodium hydroxide solution and / or a potassium hydroxide solution;

[0016] and / or, the concentration of the alkaline solution is 1 to 20 mol / L, and more preferably 6 to 12 mol / L;

[0017] and / or, the molar ratio of the titanium source to the alkaline solution is 1:2 to 50, and more preferably 1:10 to 20;

[0018] and / or, the temperature of the hydrothermal reaction is 120 to 200 °C, and the time of the hydrothermal reaction is 12 to 96 h.

[0019] Further, in Step S12, the concentration of the acidic solution is 0.01 to 5 mol / L;

[0020] and / or, the acidic solution includes a hydrochloric acid solution and / or a nitric acid solution;

[0021] and / or, the alcohol is at least one of aromatic alcohols with 6 to 15 carbon atoms;

[0022] and / or, the molar ratio of the alcohol to the titanium source is 0.1 to 10:1.

[0023] Further, in Step S14, the second calcination includes first performing oxygen-containing calcination in an oxygen-containing atmosphere and then performing inert calcination in an inert atmosphere.

[0024] Further, the oxygen-containing atmosphere includes air and / or oxygen.

[0025] Further, the temperature of the oxygen-containing calcination is 200 to 450 °C, and the time of the oxygen-containing calcination is 1 to 4 h.

[0026] Further, the inert atmosphere includes at least one of argon and / or nitrogen.

[0027] Further, the temperature of the inert calcination is 500 - 700 °C, and the time of the inert calcination is 2 - 6 h.

[0028] Further, in step S2, the temperature of the first calcination is 300 - 600 °C, and the time of the first calcination is 2 - 4 h.

[0029] Further, the M source includes at least one of a Re source, a Ru source, a Mo source, a V source, a Ce source, a Zn source, and a Cr source; wherein, the Re source is selected from at least one of rhenium chloride, perrhenic acid, and ammonium perrhenate; the Ru source is selected from ruthenium chloride and / or ruthenium acetate; the Mo source is selected from at least one of ammonium molybdate tetrahydrate, molybdenum chloride, phosphomolybdic acid, and ammonium phosphomolybdate; the V source is selected from ammonium metavanadate and / or vanadyl trichloride; the Ce source is selected from at least one of cerium nitrate, cerium chloride, cerium sulfate, and cerium acetate; the Zn source is selected from at least one of zinc nitrate, zinc chloride, zinc sulfate, and zinc acetate; the Cr source is selected from at least one of chromium nitrate, chromium sulfate, and chromium acetate.

[0030] According to the third aspect of the present invention, a method for synthesizing pyraclonil is provided. The synthesis method includes: an oxidation reaction of a thioether intermediate of formula (A) with hydrogen peroxide under the action of a catalyst to obtain pyraclonil. The synthesis schematic diagram of pyraclonil is as follows:

[0031]

[0032] Wherein, the catalyst is the titanium-based catalyst provided in the first aspect above or the titanium-based catalyst obtained by the preparation method provided in the second aspect above.

[0033] Further, the catalyst is loaded in a fixed bed, and the temperature of the oxidation reaction is 45 - 60 °C.

[0034] Applying the technical solution of the present invention, the titanium-based catalyst provided in the present application uses titanium dioxide nanoribbons with oxygen vacancy defects (V o ) as the main active component, and a promoter metal component M is doped in the titanium dioxide nanoribbons. Due to the loss of lattice oxygen in the titanium dioxide nanoribbons, some tetravalent Ti 4+ is reduced to generate Ti 3+ , and adjacent Ti 3+ and oxygen vacancies (V o ) form Ti 3+ -V o -Ti 3+ surface defect sites. The titanium dioxide nanoribbons have the characteristics of a large specific surface area and sufficient exposure of active sites. In the reaction of synthesizing pyraclonil by thioether oxidation, coordinatively unsaturated Ti 3+ -Vo -Ti 3+ Surface defect sites can enhance the adsorption and activation of reactants. Adjacent Ti 3+ can form stable Ti 3+ -S-Ti 3+ and Ti 3+ -O-Ti 3+ bonds with thioether and hydrogen peroxide, thus improving the reaction kinetics of the oxidation process. Moreover, titanium dioxide nanobelts have good wettability and ductility, which contribute to the diffusion and transport of reactant molecules, thereby increasing the reaction rate.

[0035] In addition, due to the higher energy of the Ti 3+ -V o -Ti 3+ surface defect sites, oxygen vacancies (V o ) can have an electronic interaction with promoter metal ions. Through the Ti 3+ -V o -Ti 3+ electronic localization centers formed by the surface defect sites, the promoter metal component M is anchored, improving the dispersion and stability of the promoter metal component M on the titanium dioxide nanobelts. Furthermore, more reactive sites are provided, and at the same time, the service life of the titanium-based catalyst is extended, which is beneficial to the efficient and stable oxidation of thioether to sulfone in the reaction.

[0036] The titanium-based catalyst provided by this application, when used in a fixed bed for the oxidation synthesis of oxasulfuron from thioether intermediates, has a raw material conversion rate of 100% and a relatively high product selectivity, and also realizes the continuous production of oxasulfuron. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0038] Figure 1 shows the SEM image of the titanium dioxide nanobelt prepared in Example 1 of the present invention;

[0039] Figure 2 shows the TEM image of the titanium dioxide nanobelt prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0041] As analyzed in the background art of the present application, when tungsten catalysts, molybdenum catalysts or niobium catalysts in the prior art are used as catalysts for synthesizing pyraoxystrobin, there are problems such as high cost, inability to continuously produce pyraoxystrobin, long reaction cycle, high post-treatment cost, slow reaction kinetics, difficulty in long-term production in a fixed bed, poor catalytic activity, and low reaction selectivity. To solve this problem, the present application provides a titanium-based catalyst, a preparation method thereof, and a synthesis method of pyraoxystrobin.

[0042] In a typical embodiment of the present application, a titanium-based catalyst is provided, which is characterized by including: a main active component and a promoter metal component M doped in the main active component; wherein, the main active component is titanium dioxide nanoribbons, and the titanium dioxide nanoribbons form oxygen vacancy defects, and the concentration of the oxygen vacancy defects is 5-20 μmol / g; the promoter metal component M includes at least one of Re, Ru, Mo, V, Ce, Zn, and Cr.

[0043] The titanium-based catalyst provided by the present application uses titanium dioxide nanoribbons with oxygen vacancy defects (V o ) as the main active component, and the promoter metal component M is doped in the titanium dioxide nanoribbons. Due to the loss of lattice oxygen in the titanium dioxide nanoribbons, part of the tetravalent Ti 4+ is reduced to generate Ti 3+ , and adjacent Ti 3+ and oxygen vacancies (V o ) form Ti 3+ -V o -Ti 3+ surface defect sites. The titanium dioxide nanoribbons have the characteristics of a large specific surface area and sufficient exposure of active sites. In the reaction of synthesizing pyraoxystrobin by sulfide oxidation, the coordinatively unsaturated Ti 3+ -V o -Ti 3+ surface defect sites can enhance the adsorption and activation of reactants. Adjacent Ti 3+ can form stable Ti 3+ -S-Ti 3+ and Ti 3+ -O-Ti 3+ bonds with sulfide and hydrogen peroxide, thereby improving the reaction kinetics of the oxidation process. And the titanium dioxide nanoribbons have good wettability and ductility, which helps the diffusion and transport of reactant molecules, thereby increasing the reaction rate.

[0044] In addition, since the Ti 3+ -V o -Ti 3+ surface defect sites have higher energy, the oxygen vacancies (V o ) can have an electronic interaction with the promoter metal ions, and through Ti 3+-V o -Ti 3+ The electron localization centers formed by the defect sites anchor the promoter metal component M, improving the dispersion and stability of the promoter metal component M on the titanium dioxide nanoribbons, thereby providing more reactive sites. At the same time, the service life of the titanium-based catalyst is extended, which is beneficial to the efficient and stable oxidation of thioether to sulfone in the reaction.

[0045] In the reaction of synthesizing pyraclonil by oxidizing thioether in a fixed bed using the titanium-based catalyst provided in this application, the raw material conversion rate reaches 100%, the product selectivity is relatively high, and the continuous production of pyraclonil is also realized.

[0046] In this application, the concentration of oxygen vacancy defects being "5 - 20 μmol / g" means that 1 g of titanium dioxide nanoribbons contains 5 - 20 μmol of oxygen vacancy defects.

[0047] Typical but non-limiting, the concentration of oxygen vacancy defects in the titanium dioxide nanoribbons provided in this application is, for example, 5 μmol / g, 5.03 μmol / g, 7.27 μmol / g, 8.69 μmol / g, 10 μmol / g, 11.36 μmol / g, 13.07 μmol / g, 13.52 μmol / g, 15 μmol / g, 15.38 μmol / g, 16.21 μmol / g, 19.61 μmol / g, 20 μmol / g or a range value composed of any two numerical values.

[0048] To further improve the conversion rate and product selectivity of the oxidation of thioether to pyraclonil, it is preferred that the mass ratio of the promoter metal component M to the titanium dioxide nanoribbons in the titanium-based catalyst is 0.5 - 5:100.

[0049] In this application, the promoter metal component M can be any one or more of Re, Ru, Mo, V, Ce, Zn, and Cr. When the promoter metal component M is Re, the mass ratio of Re to the titanium dioxide nanoribbons is 0.5 - 5:100; when the promoter metal component M is Ru, the mass ratio of Ru to the titanium dioxide nanoribbons is 0.5 - 5:100; when the promoter metal component M is Mo, the mass ratio of Mo to the titanium dioxide nanoribbons is 0.5 - 5:100; when the promoter metal component M is V, the mass ratio of V to the titanium dioxide nanoribbons is 0.5 - 5:100; when the promoter metal component M is Ce, the mass ratio of Ce to the titanium dioxide nanoribbons is 0.5 - 5:100; when the promoter metal component M is Zn, the mass ratio of Zn to the titanium dioxide nanoribbons is 0.5 - 5:100; when the promoter metal component M is Cr, the mass ratio of Cr to the titanium dioxide nanoribbons is 0.5 - 5:100.

[0050] When the promoter metal component M is any two of Re, Ru, Mo, V, Ce, Zn, and Cr, the mass ratio of the total mass of the two promoter metal components to the mass of the titanium dioxide nanoribbons is 0.5 - 5:100. The two promoter metal components can be, for example, Re and Ru; Ru and Mo; Mo and V; V and Ce; Ce and Zn; Zn and Cr, etc.

[0051] When the promoter metal component M is any three of Re, Ru, Mo, V, Ce, Zn, and Cr, the mass ratio of the total mass of the three promoter metal components to the mass of the titanium dioxide nanoribbons is 0.5 - 5:100. The three promoter metal components can be, for example, Re, Ru, and Mo; Re, Ce, and V; Ce, Zn, and Cr; Mo, Zn, and V; Re, Cr, and V; Ru, Cr, and Zn, etc.

[0052] When the promoter metal component M is any four of Re, Ru, Mo, V, Ce, Zn, and Cr, the mass ratio of the total mass of the four promoter metal components to the mass of the titanium dioxide nanoribbons is 0.5 - 5:100. The four promoter metal components can be, for example, Re, Ru, Mo, and V; Re, Ru, Mo, and Ce; V, Ce, Zn, and Cr, etc.

[0053] When the promoter metal component M is any five of Re, Ru, Mo, V, Ce, Zn, and Cr, the mass ratio of the total mass of the five promoter metal components to the mass of the titanium dioxide nanoribbons is 0.5 - 5:100. The five promoter metal components can be, for example, Re, Ru, Mo, V, and Ce; Re, Ru, Mo, V, and Zn; Re, Ru, Mo, V, and Cr, etc.

[0054] When the promoter metal component M is any six of Re, Ru, Mo, V, Ce, Zn, and Cr, the mass ratio of the total mass of the six promoter metal components to the mass of the titanium dioxide nanoribbons is 0.5 - 5:100. The six promoter metal components can be, for example, Re, Ru, Mo, V, Ce, and Zn; Re, Ru, Mo, V, Ce, and Cr, etc.

[0055] When the promoter metal component M is Re, Ru, Mo, V, Ce, Zn, and Cr, the mass ratio of the total mass of these seven promoter metal components to the mass of the titanium dioxide nanoribbons is 0.5 - 5:100.

[0056] Typical but non - limiting, in the titanium - based catalyst provided by the present application, the mass ratio of the promoter metal active component M to the titanium dioxide nanoribbons can be, for example, 0.5:100, 1:100, 2:100, 3:100, 4:100, 5:100, or a range value composed of any two numerical values.

[0057] In order to further increase the specific surface area of the catalyst, increase the number of exposed active metal atoms, further enhance the adsorption and activation of reactants, and improve the reaction kinetics of the thioether oxidation process, it is preferred that the titanium dioxide nanoribbons are nanoribbon-shaped with a thickness of 1-5 nm.

[0058] Typically but not restrictively, the thickness of the titanium dioxide nanoribbons can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, or a range value composed of any two of these values.

[0059] In order to more favorably load the titanium-based catalyst provided in this application into a fixed bed for the continuous synthesis of oxasulfuron, in some embodiments, the titanium-based catalyst provided in this application is granular, and its average particle size is, for example, 20-40 mesh, such as 20 mesh, 25 mesh, 30 mesh, 35 mesh, 40 mesh, or a range value composed of any two of these values.

[0060] In another typical embodiment of this application, a preparation method of the titanium-based catalyst provided in the first typical embodiment above is provided, including the following steps: Step S1, preparing titanium dioxide nanoribbons with oxygen vacancy defects; Step S2, mixing the titanium dioxide nanoribbons, M source, and water, and then successively performing first drying and first calcination to obtain the titanium-based catalyst.

[0061] In this application, first, the titanium dioxide nanoribbons with oxygen vacancy defects, M source, and water are mixed and uniformly dispersed. Utilize the fact that the Ti 3+ -V o -Ti 3+ surface defect sites have higher energy, and the oxygen vacancy (V o ) can have an electronic interaction with metal ions in the M source. Through the Ti 3+ -V o -Ti 3+ defect sites to form an electron localization center to anchor the metal ions in the M source, improving the dispersibility and stability of the M source on the titanium dioxide nanoribbons. And the titanium dioxide nanoribbons have good wettability and ductility, which helps the shaping of the titanium-based catalyst. Then, after removing the solvent by first drying and performing first calcination, the titanium-based catalyst can be obtained. The preparation method provided in this application has a low preparation cost and is simple to operate, and can realize the continuous production of oxasulfuron in a fixed bed.

[0062] In some embodiments, the above step S1 includes: Step S11, mixing a titanium source with an alkaline solution and performing a hydrothermal reaction to obtain a titanate; Step S12, mixing the titanate, alcohol, and an acidic solution for ion exchange to obtain titanic acid nanoribbons; Step S13, washing and second drying the titanic acid nanoribbons in sequence to obtain a titanium dioxide nanoribbon precursor; Step S14, performing second calcination on the titanium dioxide nanoribbon precursor to obtain titanium dioxide nanoribbons.

[0063] This application uses a titanium source as a raw material. First, the titanium source is subjected to a hydrothermal reaction under alkaline conditions, and the titanium source reacts with the alkaline solution to obtain titanate. Subsequently, the obtained titanate is mixed with an alcohol and an acidic solution for ion exchange. The titanate and H in the acidic solution + carry out sufficient ion exchange and self-assemble to form titanic acid nanoribbons with the assistance of alcohol. The titanic acid nanoribbons are washed to remove the residual H on the surface + , and the solvent is removed by the second drying to obtain a titanium dioxide nanoribbon precursor. Then, through the second calcination, the alcohol organic matter adsorbed on the surface of the titanium dioxide nanoribbon precursor decomposes and consumes the lattice oxygen, thereby forming oxygen vacancy defects (V o ). In addition, the titanic acid nanoribbons have the structural properties of two-dimensional materials. Under high-temperature calcination conditions, the surface atoms can escape from the lattice to form oxygen vacancy defects (V o ). Due to the loss of lattice oxygen, part of the tetravalent Ti 4+ is reduced to generate Ti 3+ , and adjacent Ti 3+ and oxygen vacancies (V o ) form Ti 3+ -V o -Ti 3+ surface defect sites. Thus, titanium dioxide nanoribbons with oxygen vacancy defects are obtained, and the thickness of the titanium dioxide nanoribbons is relatively thin, which further promotes the escape of surface atoms from the lattice to form oxygen vacancy defects (V o ).

[0064] In the above step S11, in order to further promote the formation of titanate, it is preferred that the titanium source is any one or more of titanium dioxide, titanium oxysulfate, and P25 titanium dioxide.

[0065] In order to further increase the rate of the hydrothermal reaction of the titanium source to generate titanate under alkaline conditions, it is preferred that the concentration of the alkaline solution is 1-20 mol / L, more preferably 6-12 mol / L. And it is further preferred that the alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution.

[0066] Typical but non-limiting, it is preferred that the concentration of the alkaline solution is, for example, 1 mol / L, 6 mol / L, 10 mol / L, 12 mol / L, 16 mol / L, 20 mol / L, or a range value composed of any two values.

[0067] In order to further ensure the completeness and selectivity of the hydrothermal reaction to further improve the yield and purity of titanate, it is preferred that the molar ratio of the titanium source to the alkaline solution is 1:2-50, and more preferably 1:10-20.

[0068] Typical but non-limiting, the molar ratio of the titanium source to the alkaline solution is, for example, 1:2, 1:6, 1:10, 1:15, 1:20, 1:30, 1:40, 1:50, or a range value composed of any two numerical values.

[0069] To further increase the rate of the hydrothermal reaction and the yield of titanate, it is preferred that the temperature of the hydrothermal reaction is 120 - 200 °C and the time of the hydrothermal reaction is 12 - 96 h; more preferably, the temperature of the hydrothermal reaction is 150 - 180 °C and the time of the hydrothermal reaction is 36 - 72 h.

[0070] Typical but non-limiting, the temperature of the hydrothermal reaction is, for example, 120 °C, 140 °C, 150 °C, 155 °C, 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 190 °C, 200 °C, or a range value composed of any two numerical values; the time of the hydrothermal reaction is, for example, 12 h, 24 h, 36 h, 42 h, 48 h, 54 h, 60 h, 66 h, 72 h, 84 h, 96 h, or a range value composed of any two numerical values.

[0071] In the above step S12, since the concentration of hydrogen ions during the ion exchange process will affect the growth and formation process of titanate nanoribbons, in order to further control the morphology, structure, and properties of titanate nanoribbons, it is preferred that the concentration of the acidic solution is 0.01 - 5 mol / L; and more preferably, the acidic solution includes hydrochloric acid solution and / or nitric acid solution.

[0072] Typical but non-limiting, the concentration of the acidic solution is, for example, 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, or a range value composed of any two numerical values.

[0073] To further promote the formation of titanate nanoribbons, it is preferred that the alcohol is any one or more of aromatic alcohols with 6 - 15 carbon atoms. Aromatic alcohols have strong coordination complexing ability and stability. Under the action of aromatic groups and hydrophobicity, it is more conducive to interacting with titanate to form a layered titanate structure and finally form the structure of titanate nanoribbons.

[0074] To further increase the content of alcohol organic compounds adsorbed on the surface of titanate nanoribbons, and thus further increase the number of oxygen vacancy defects (V o ) formed after the decomposition and consumption of lattice oxygen by alcohol organic compounds. It is preferred that the molar ratio of alcohol to titanium source is 0.1 - 10:1.

[0075] Typical but non-limiting, the molar ratio of alcohol to titanium source is, for example, 0.1:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, 8:1, 10:1, or a range value composed of any two numerical values.

[0076] To further improve the mixing uniformity of the titanate, alcohol, and acidic solution in step S12, it is preferred that the mixing method is stirring, and it is further preferred that the stirring time is 1 - 6 h.

[0077] In the above step S13, to further ensure the removal of the residual H + on the surface of the titanate nanobelts, it is preferred to wash with deionized water and wash the titanate nanobelts with water until the pH = 4 - 7 before proceeding with subsequent steps, such as a range value composed of any two values among 4, 5, 6, 7.

[0078] In the above step S13, to further promote the drying of the titanate nanobelts, it is preferred to first perform suction filtration on the washed titanate nanobelts and then dry overnight, and it is further preferred that the temperature of the second drying is 60 - 120 °C.

[0079] In some embodiments, in step S14, the second calcination includes first performing an oxygen-containing calcination in an oxygen-containing atmosphere and then performing an inert calcination in an inert atmosphere. First, perform an oxygen-containing calcination in an oxygen-containing atmosphere to promote the decomposition and consumption of lattice oxygen by the alcohol organic matter adsorbed on the surface of the titanate nanobelts, thereby forming oxygen vacancy defects (V o ). Subsequently, perform an inert calcination in an inert atmosphere to promote the escape of surface atoms of the titanate nanobelts from the lattice to form oxygen vacancy defects (V o ). The calcination under two different atmosphere conditions can further promote the formation of oxygen vacancy defects (V o ).

[0080] To further improve the decomposition and consumption of lattice oxygen by the alcohol organic matter, it is preferred that the oxygen-containing atmosphere includes air and / or oxygen; it is preferred that the temperature of the oxygen-containing calcination is 200 - 450 °C, and the time of the oxygen-containing calcination is 1 - 4 h; it is further preferred that the temperature of the oxygen-containing calcination is 300 - 400 °C, and the time of the oxygen-containing calcination is 2 - 3 h; it is preferred that the heating rate of the oxygen-containing calcination is 5 - 15 °C / min.

[0081] Typical but non-limiting, the temperature of the oxygen-containing calcination is, for example, 200 °C, 300 °C, 350 °C, 400 °C, 450 °C, or a range value composed of any two values; the time of the oxygen-containing calcination is, for example, 1 h, 2 h, 3 h, 4 h, or a range value composed of any two values; the heating rate of the oxygen-containing calcination is, for example, 5 °C / min, 8 °C / min, 10 °C / min, 12 °C / min, 15 °C / min, or a range value composed of any two values.

[0082] To further promote the escape of surface atoms of the titanium acid nanoribbons from the lattice to form oxygen vacancy defects, the inert atmosphere is preferably argon and / or nitrogen; the temperature of the inert calcination is preferably 500-700 °C, and the time of the inert calcination is 2-6 h; more preferably, the temperature of the inert calcination is 600-650 °C, and the time of the inert calcination is 3-4 h; the heating rate of the inert calcination is preferably 5-15 °C / min.

[0083] Typical but non-limiting, the temperature of the inert calcination is, for example, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C or a range value composed of any two values; the time of the inert calcination is, for example, 2 h, 3 h, 4 h, 5 h, 6 h or a range value composed of any two values; the heating rate of the inert calcination is, for example, 5 °C / min, 8 °C / min, 10 °C / min, 12 °C / min, 15 °C / min or a range value composed of any two values.

[0084] In the above step S2, to further promote the uniform mixing and dispersion of the titanium dioxide nanoribbons and the M source in water, the mixing method is preferably ultrasonic dispersion, and the time of ultrasonic dispersion is preferably 1-2 h.

[0085] In the above step S2, to further increase the rate of solvent removal, the temperature of the first drying is preferably 80-100 °C.

[0086] The above M source includes any one or more of a Re source, a Ru source, a Mo source, a V source, a Ce source, a Zn source and a Cr source; wherein, the Re source includes but is not limited to any one or more of rhenium chloride, perrhenic acid and ammonium perrhenate, and is further preferably rhenium chloride; the Ru source includes but is not limited to ruthenium chloride and / or ruthenium acetate, and is further preferably ruthenium chloride; the Mo source includes but is not limited to any one or more of ammonium molybdate tetrahydrate, molybdenum chloride, phosphomolybdic acid and ammonium phosphomolybdate, and is further preferably ammonium molybdate tetrahydrate; the V source includes but is not limited to ammonium metavanadate and / or vanadium oxychloride, and is further preferably ammonium metavanadate; the Ce source includes but is not limited to any one or more of cerium nitrate, cerium chloride, cerium sulfate and cerium acetate, and is further preferably cerium nitrate; the Zn source includes but is not limited to any one or more of zinc nitrate, zinc chloride, zinc sulfate and zinc acetate, and is further preferably zinc nitrate; the Cr source includes but is not limited to any one or more of chromium nitrate, chromium sulfate and chromium acetate, and is further preferably chromium nitrate.

[0087] In the above step S2, in order to further strengthen the binding between metal ions in the M source and titanium dioxide nanoribbons and further improve the stability and activity of the catalyst, the temperature of the first calcination is preferably 300-600 °C, and the time of the first calcination is 2-4 h. And to further promote production efficiency and the stability of the catalyst, the heating rate of the first calcination is preferably 5-15 °C / min, and the atmosphere of the first calcination is preferably an oxygen-containing atmosphere or an inert atmosphere.

[0088] Typical but non-limiting, the temperature of the first calcination is, for example, 300 °C, 400 °C, 500 °C, 600 °C or a range value composed of any two values; the time of the first calcination is, for example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h or a range value composed of any two values; the heating rate of the first calcination is, for example, 5 °C / min, 8 °C / min, 10 °C / min, 12 °C / min, 15 °C / min or a range value composed of any two values.

[0089] In some embodiments, in order to facilitate loading the above titanium-based catalyst into a fixed bed for the continuous synthesis of oxasulfuron, the above step S2 further includes tabletting and crushing the titanium-based catalyst in sequence, so as to obtain a titanium-based catalyst with an average particle size of 20-40 mesh.

[0090] In the third typical embodiment of the present application, a method for synthesizing oxasulfuron is also provided. The synthesis method includes: oxidizing a thioether intermediate and hydrogen peroxide under the action of a catalyst to obtain oxasulfuron. The synthesis schematic diagram of the oxasulfuron is as follows:

[0091]

[0092] Among them, the above catalyst is the titanium-based catalyst provided by the above first typical embodiment or the titanium-based catalyst obtained according to the preparation method provided by the above second typical embodiment.

[0093] The synthesis method of oxasulfuron provided by the present application loads the above catalyst on a fixed bed, so that the thioether intermediate and hydrogen peroxide are continuously synthesized into oxasulfuron in the fixed bed under the catalytic action of the catalyst. And the raw material conversion rate reaches 100%, the product selectivity is relatively high, and the production cost is reduced.

[0094] In addition, the present application uses titanium dioxide nanoribbons containing oxygen vacancy defects (V o ) as the main active component, and dopes the auxiliary metal active component M in the titanium dioxide nanoribbons. The titanium dioxide nanoribbons are nanoribbon-shaped, and have the characteristics of large specific surface area, sufficient exposure of active sites, good wettability and ductility. In the reaction of oxidizing thioether to synthesize oxasulfuron, the reaction kinetics and reaction rate of the oxidation process are improved. Through Ti 3+ -Vo -Ti 3+ The electron localization centers formed by the defect sites anchor the metal component M of the dispersion aid, improving the dispersion and stability of the metal component M of the aid on the titanium dioxide nanobelts, thereby providing more reactive sites and enhancing the reaction activity. At the same time, the service life of the catalyst is extended, thus reducing the catalyst usage cost.

[0095] In some embodiments, the temperature of the above oxidation reaction is 45 - 60 °C, the reaction is milder, which is more conducive to process control. Moreover, the catalyst is loaded in a fixed bed and can be used continuously.

[0096] In some specific embodiments, when continuously preparing sulfentrazone using a fixed bed, an acetonitrile solution of a thioether intermediate with a flow rate of 0.5 g / min (the mass ratio of acetonitrile to the thioether intermediate is 3:1) is introduced into the fixed bed, and an aqueous hydrogen peroxide solution with a flow rate of 0.1 g / min (mass concentration of 50 wt%) is introduced into the fixed bed for reaction.

[0097] The beneficial effects of the present application will be further illustrated below with reference to examples and comparative examples.

[0098] Example 1

[0099] This example provides a titanium-based catalyst. The titanium-based catalyst includes titanium dioxide nanobelts with oxygen vacancy defects formed as the main active component. The titanium dioxide nanobelts are doped with promoter rhenium, promoter ruthenium, and promoter molybdenum, and the mass ratio of promoter rhenium to titanium dioxide nanobelts is 0.5:100, the mass ratio of promoter ruthenium to titanium dioxide nanobelts is 1:100, and the mass ratio of promoter molybdenum to titanium dioxide nanobelts is 2:100.

[0100] The preparation method of the titanium-based catalyst includes the following steps:

[0101] (1) Prepare titanium dioxide nanobelts with oxygen vacancy defects

[0102] (1.1) Mix 0.2 mol of P25 titanium dioxide powder evenly with 500 mL of 8 M NaOH solution, transfer it to a hydrothermal autoclave with a liner, place the hydrothermal autoclave in an oven, heat it at 160 °C for 36 h for hydrothermal reaction. After the hydrothermal reaction ends, perform suction filtration to remove the residual NaOH solution to obtain white sodium titanate solid;

[0103] (1.2) Add the white sodium titanate solid to a 1 M HCl solution containing 0.5 mol of 2-phenylisopropanol, stir for 3 h, and perform alcohol-assisted ion exchange self-assembly to generate titanic acid nanobelts;

[0104] (1.3) First, wash the titanium acid nanoribbons with deionized water until the pH = 5, then perform suction filtration, and subsequently place them in an oven for drying at 80 °C to obtain a titanium dioxide nanoribbon precursor;

[0105] (1.4) Bake the titanium dioxide nanoribbon precursor in air at 350 °C for 3 h at a heating rate of 5 °C / min; subsequently, change the baking atmosphere to argon and bake it in argon at 600 °C for 4 h at a heating rate of 5 °C / min; after the baking is completed, cool it naturally to room temperature to obtain titanium dioxide nanoribbons;

[0106] (2) Add rhenium chloride, ruthenium chloride, and ammonium molybdate tetrahydrate to a beaker and disperse and dissolve them in 200 mL of deionized water. Subsequently, add titanium dioxide nanoribbons. Among them, based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 0.5:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 1:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 2:100. Ultrasonically disperse for 1 h, and then evaporate to remove the solvent at 85 °C to obtain a dry solid. Heat the dry solid in air at a heating rate of 5 °C / min to raise the temperature to 450 °C and bake for 3 h to obtain a powdery titanium-based catalyst. After simply pressing the powdery titanium-based catalyst with a tablet press, crush it to 20 - 40 mesh to obtain the aforementioned titanium-based catalyst.

[0107] Example 2

[0108] This example provides a titanium-based catalyst. The titanium-based catalyst includes titanium dioxide nanoribbons with oxygen vacancy defects formed as the main active component. The titanium dioxide nanoribbons are doped with promoter rhenium, promoter cerium, and promoter vanadium, and the mass ratio of promoter rhenium to titanium dioxide nanoribbons is 0.5:100, the mass ratio of promoter cerium to titanium dioxide nanoribbons is 1:100, and the mass ratio of promoter vanadium to titanium dioxide nanoribbons is 2:100.

[0109] The preparation method of the titanium-based catalyst includes the following steps:

[0110] (1) Prepare titanium dioxide nanoribbons with oxygen vacancy defects

[0111] (1.1) Mix 0.2 mol of P25 titanium dioxide powder evenly with 500 mL of 12 M NaOH solution, transfer it to a hydrothermal autoclave with a liner, place the hydrothermal autoclave in an oven, heat it at 170 °C for 48 h, and perform suction filtration to remove the residual NaOH solution after the hydrothermal reaction to obtain a white sodium titanate solid;

[0112] (1.2) Add the white sodium titanate solid to 5 M HNO containing 1 mol of o-cresol 3In the solution, stir for 1 h to carry out alcohol-assisted ion exchange self-assembly to generate titanium acid nanoribbons;

[0113] (1.3)First, wash the titanium acid nanoribbons with deionized water until the pH = 7, then carry out suction filtration, and then place them in an oven and dry at 90 °C to obtain a titanium dioxide nanoribbon precursor;

[0114] (1.4)Calcine the titanium dioxide nanoribbon precursor in air at 450 °C for 3 h at a heating rate of 10 °C / min; then change the calcination atmosphere to argon and calcine in argon at 700 °C for 2 h at a heating rate of 5 °C / min; after the calcination is completed, cool naturally to room temperature to obtain titanium dioxide nanoribbons;

[0115] (2)Add rhenium chloride, cerium nitrate and ammonium metavanadate to a beaker and disperse and dissolve them in 200 mL of deionized water. Then add titanium dioxide nanoribbons. Among them, based on rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 0.5:100; based on cerium in cerium nitrate, the mass ratio of cerium nitrate to titanium dioxide nanoribbons is 1:100; based on vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanoribbons is 2:100. Ultrasonically disperse for 2 h, and then evaporate the solvent at 90 °C to obtain a dry solid. Calcinate the dry solid in air at a heating rate of 10 °C / min to raise the temperature to 550 °C for 2 h to obtain a powdered titanium-based catalyst. After simply pressing the powdered titanium-based catalyst with a tablet press, crush it to 20-40 mesh to obtain the aforementioned titanium-based catalyst.

[0116] Example 3

[0117] This example provides a titanium-based catalyst. The titanium-based catalyst includes titanium dioxide nanoribbons with oxygen vacancy defects formed as the main active component. The titanium dioxide nanoribbons are doped with promoter cerium, promoter zinc and promoter chromium. The mass ratio of promoter cerium to titanium dioxide nanoribbons is 1:100, the mass ratio of promoter zinc to titanium dioxide nanoribbons is 2:100, and the mass ratio of promoter chromium to titanium dioxide nanoribbons is 1:100.

[0118] The preparation method of the titanium-based catalyst includes the following steps:

[0119] (1)Prepare titanium dioxide nanoribbons with oxygen vacancy defects

[0120] (1.1)Mix 0.2 mol of titanium oxysulfate evenly with 500 mL of 15 M NaOH solution, transfer it to a hydrothermal autoclave with a liner, place the hydrothermal autoclave in an oven, heat it at 140 °C for 72 h, and carry out suction filtration to remove the residual NaOH solution after the hydrothermal reaction to obtain a white sodium titanate solid;

[0121] (1.2) Place the white sodium titanate solid in a 0.1 M HCl solution containing 0.5 mol of benzyl alcohol, stir for 6 h, and perform alcohol-assisted ion exchange self-assembly to generate titanic acid nanoribbons;

[0122] (1.3) First, wash the titanic acid nanoribbons with deionized water until the pH = 4, then perform suction filtration, and then place them in an oven and dry at 110 °C to obtain a titanium dioxide nanoribbon precursor;

[0123] (1.4) Bake the titanium dioxide nanoribbon precursor in air at a heating rate of 5 °C / min at 300 °C for 4 h; then change the baking atmosphere to argon and bake in argon at 550 °C at a heating rate of 10 °C / min for 6 h. After baking, cool naturally to room temperature to obtain titanium dioxide nanoribbons;

[0124] (2) Add cerium nitrate, zinc nitrate, and chromium nitrate to a beaker and disperse and dissolve them in 200 mL of deionized water. Then add titanium dioxide nanoribbons. Among them, based on cerium in cerium nitrate, the mass ratio of cerium to titanium dioxide nanoribbons is 1:100; based on zinc in zinc nitrate, the mass ratio of zinc to titanium dioxide nanoribbons is 2:100; based on chromium in chromium nitrate, the mass ratio of chromium to titanium dioxide nanoribbons is 1:100. Ultrasonically disperse for 2 h, and then evaporate the solvent at 95 °C to obtain a dry solid. Heat the dry solid in air at a heating rate of 5 °C / min to 400 °C and bake for 4 h to obtain a powdered titanium-based catalyst. After simply pressing the powdered titanium-based catalyst with a tablet press, crush it to 20-40 mesh to obtain the aforementioned titanium-based catalyst.

[0125] Example 4

[0126] This example provides a titanium-based catalyst. The titanium-based catalyst includes titanium dioxide nanoribbons with oxygen vacancy defects formed as the main active component. The titanium dioxide nanoribbons are doped with promoter molybdenum, promoter zinc, and promoter vanadium. The mass ratio of promoter molybdenum to titanium dioxide nanoribbons is 3:100, the mass ratio of promoter zinc to titanium dioxide nanoribbons is 1:100, and the mass ratio of promoter vanadium to titanium dioxide nanoribbons is 1:100.

[0127] The preparation method of the titanium-based catalyst includes the following steps:

[0128] (1) Prepare titanium dioxide nanoribbons with oxygen vacancy defects

[0129] (1.1) Mix 0.2 mol of titanium dioxide with 500 mL of 10 M NaOH solution evenly, transfer it to a hydrothermal reactor with a liner, place the hydrothermal reactor in an oven, heat it at 190 °C for 24 h, and after the hydrothermal reaction ends, filter to remove the residual NaOH solution to obtain a white sodium titanate solid;

[0130] (1.2) Place the white sodium titanate solid in a 5 M HCl solution containing 0.1 mol of styrene alcohol, stir for 4 h, and carry out alcohol-assisted ion exchange self-assembly to generate titanic acid nanoribbons;

[0131] (1.3) First wash the titanic acid nanoribbons with deionized water until the pH = 6, then carry out suction filtration, and then place them in an oven and dry at 100 °C to obtain a titanium dioxide nanoribbon precursor;

[0132] (1.4) Bake the titanic acid nanoribbons in air at a heating rate of 5 °C / min for 4 h at 250 °C; then change the baking atmosphere to argon, and bake at a rate of 10 °C / min for 5 h in argon at 650 °C. After the baking is completed, cool naturally to room temperature to obtain titanium dioxide nanoribbons;

[0133] (2) Add ammonium molybdate tetrahydrate, zinc nitrate, and ammonium metavanadate to a beaker and disperse and dissolve them in 200 mL of deionized water. Then add titanium dioxide nanoribbons. Among them, based on molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 3:100; based on zinc in zinc nitrate, the mass ratio of zinc to titanium dioxide nanoribbons is 1:100; based on vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanoribbons is 1:100. Ultrasonically disperse for 2 h, and then evaporate the solvent at 100 °C to obtain a dry solid. Heat the dry solid in air at a heating rate of 10 °C / min to 600 °C and bake for 2 h to obtain a powdery titanium-based catalyst. After simply pressing the powdery titanium-based catalyst with a tablet press, crush it to 20-40 mesh to obtain the aforementioned titanium-based catalyst.

[0134] Example 5

[0135] This example provides a titanium-based catalyst. The titanium-based catalyst includes titanium dioxide nanoribbons with oxygen vacancy defects formed, which serve as the main active component. The titanium dioxide nanoribbons are doped with promoter rhenium, promoter chromium, and promoter vanadium. The mass ratio of promoter rhenium to titanium dioxide nanoribbons is 0.5:100, the mass ratio of promoter chromium to titanium dioxide nanoribbons is 1:100, and the mass ratio of promoter vanadium to titanium dioxide nanoribbons is 3:100.

[0136] The preparation method of the titanium-based catalyst includes the following steps:

[0137] (1) Prepare titanium dioxide nanoribbons with oxygen vacancy defects

[0138] (1.1) Mix 0.2 mol of titanium dioxide powder evenly with 500 mL of 20 M NaOH solution, transfer it to a hydrothermal autoclave with a lining, place the hydrothermal autoclave in an oven, heat it at 120 °C for 96 h, and after the hydrothermal reaction ends, carry out suction filtration to remove the residual NaOH solution to obtain a white sodium titanate solid;

[0139] (1.2) Place the white sodium titanate solid in a 0.5 M HCl solution containing 0.02 mol of cinnamyl alcohol, stir for 4 h, and perform alcohol-assisted ion-exchange self-assembly to generate titanic acid nanoribbons;

[0140] (1.3) First, wash the titanic acid nanoribbons with deionized water until the pH = 7, then perform suction filtration, and then place them in an oven and dry at 120 °C to obtain a titanium dioxide nanoribbon precursor;

[0141] (1.4) Bake the titanium dioxide nanoribbon precursor in air at a heating rate of 15 °C / min for 4 h at 450 °C; then change the baking atmosphere to argon and bake in argon at a heating rate of 10 °C / min for 3 h at 700 °C; after baking, naturally cool to room temperature to obtain titanium dioxide nanoribbons;

[0142] (2) Add rhenium chloride, chromium nitrate, and ammonium metavanadate to a beaker and disperse and dissolve them in 200 mL of deionized water. Then add titanium dioxide nanoribbons. Among them, based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 0.5:100; based on the chromium in chromium nitrate, the mass ratio of chromium to titanium dioxide nanoribbons is 1:100; based on the vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanoribbons is 3:100. Ultrasonically disperse for 1 h, and then evaporate the solvent at 80 °C to obtain a dry solid. Heat the dry solid in air at a heating rate of 5 °C / min to raise the temperature to 300 °C and bake for 4 h to obtain a powdered titanium-based catalyst. After simply pressing the powdered titanium-based catalyst with a tablet press, crush it to 20 - 40 mesh to obtain the aforementioned titanium-based catalyst.

[0143] Example 6

[0144] This example provides a titanium-based catalyst, which includes titanium dioxide nanoribbons with oxygen vacancy defects formed as the main active component. The titanium dioxide nanoribbons are doped with promoter ruthenium, promoter chromium, and promoter zinc, and the mass ratio of promoter ruthenium to titanium dioxide nanoribbons is 0.5:100, the mass ratio of promoter chromium to titanium dioxide nanoribbons is 1:100, and the mass ratio of promoter zinc to titanium dioxide nanoribbons is 3:100.

[0145] The preparation method of this titanium-based catalyst includes the following steps:

[0146] (1) Prepare titanium dioxide nanoribbons with oxygen vacancy defects

[0147] (1.1) Mix 0.2 mol of P25 titanium dioxide powder evenly with 500 mL of 1 M NaOH solution, transfer it to a hydrothermal reactor with a liner, place the hydrothermal reactor in an oven, heat it at 200 °C for 12 h for hydrothermal reaction. After the hydrothermal reaction is completed, filter to remove the residual NaOH solution to obtain white sodium titanate solid;

[0148] (1.2) Place the white sodium titanate solid in a 0.1 M HNO 3 solution containing 1 mol of phenylethyl alcohol, stir for 6 h, and carry out alcohol-assisted ion exchange self-assembly to generate titanic acid nanoribbons;

[0149] (1.3) First wash the titanic acid nanoribbons with deionized water until the pH = 5, then filter, and then place them in an oven to dry at 90 °C to obtain a titanium dioxide nanoribbon precursor;

[0150] (1.4) Bake the titanium dioxide nanoribbon precursor in air at a heating rate of 5 °C / min at 400 °C for 3 h, then change the baking atmosphere to argon, and bake in argon at a heating rate of 5 °C / min at 500 °C for 6 h; after baking, cool naturally to room temperature to obtain titanium dioxide nanoribbons;

[0151] (2) Add ruthenium chloride, chromium acetate and zinc nitrate to a beaker and disperse and dissolve them in 200 mL of deionized water. Then add titanium dioxide nanoribbons. Among them, based on ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 0.5:100; based on chromium in chromium acetate, the mass ratio of chromium to titanium dioxide nanoribbons is 1:100; based on zinc in zinc nitrate, the mass ratio of zinc to titanium dioxide nanoribbons is 3:100. Ultrasonically disperse for 1 h, and then evaporate to remove the solvent at 90 °C to obtain a dry solid. Heat the dry solid in air at a heating rate of 5 °C / min to 400 °C and bake for 2 h to obtain a powdered titanium-based catalyst. After simply pressing the powdered titanium-based catalyst with a tablet press, crush it to 20-40 mesh to obtain the aforementioned titanium-based catalyst.

[0152] Example 7

[0153] The difference between this example and Example 1 is that in step (1.2), the amount of 2-phenylisopropanol used is 0.02 mol, and in step (1.4), it is baked in air at 300 °C for 2 h, and then baked in argon at 500 °C for 2 h.

[0154] Example 8

[0155] The difference between this example and Example 1 is that in step (1.2), the amount of 2-phenylisopropanol used is 2 mol, and in step (1.4), it is baked in air at 450 °C for 3 h, and then baked in argon at 650 °C for 5 h.

[0156] Example 9

[0157] The difference between this example and Example 1 lies in that in step (2), based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 0.1:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 0.2:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 0.2:100.

[0158] Example 10

[0159] The difference between this example and Example 1 lies in that in step (2), based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 2:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 1:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 2:100.

[0160] Example 11

[0161] The difference between this example and Example 1 lies in that only rhenium chloride is added in step (2), and based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 0.5:100.

[0162] Example 12

[0163] The difference between this example and Example 1 lies in that only rhenium chloride is added in step (2), and based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 5:100.

[0164] Example 13

[0165] The difference between this example and Example 1 lies in that only ruthenium chloride is added in step (2), and based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 0.5:100.

[0166] Example 14

[0167] The difference between this example and Example 1 lies in that only ruthenium chloride is added in step (2), and based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 5:100.

[0168] Example 15

[0169] The difference between this example and Example 1 lies in that only ammonium molybdate tetrahydrate is added in step (2), and based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 0.5:100.

[0170] Example 16

[0171] The difference between this example and Example 1 is that in step (2), only ammonium molybdate tetrahydrate is added, and based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 5:100.

[0172] Example 17

[0173] The difference between this example and Example 1 is that in step (2), only ammonium metavanadate is added, and based on the vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanoribbons is 0.5:100.

[0174] Example 18

[0175] The difference between this example and Example 1 is that in step (2), only ammonium metavanadate is added, and based on the vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanoribbons is 5:100.

[0176] Example 19

[0177] The difference between this example and Example 1 is that in step (2), only cerium nitrate is added, and based on the cerium in cerium nitrate, the mass ratio of cerium to titanium dioxide nanoribbons is 0.5:100.

[0178] Example 20

[0179] The difference between this example and Example 1 is that in step (2), only cerium nitrate is added, and based on the cerium in cerium nitrate, the mass ratio of cerium to titanium dioxide nanoribbons is 5:100.

[0180] Example 21

[0181] The difference between this example and Example 1 is that in step (2), only zinc nitrate is added, and based on the zinc in zinc nitrate, the mass ratio of zinc to titanium dioxide nanoribbons is 0.5:100.

[0182] Example 22

[0183] The difference between this example and Example 1 is that in step (2), only zinc nitrate is added, and based on the zinc in zinc nitrate, the mass ratio of zinc to titanium dioxide nanoribbons is 5:100.

[0184] Example 23

[0185] The difference between this example and Example 1 is that in step (2), only chromium nitrate is added, and based on the chromium in chromium nitrate, the mass ratio of chromium to titanium dioxide nanoribbons is 0.5:100.

[0186] Example 24

[0187] The difference between this embodiment and Embodiment 1 is that in step (2), only chromium nitrate is added, and based on the chromium in chromium nitrate, the mass ratio of chromium to titanium dioxide nanoribbons is 5:100.

[0188] Example 25

[0189] The difference between this embodiment and Embodiment 1 is that in step (2), rhenium chloride and ruthenium chloride are added, and based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 2:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 2:100.

[0190] Example 26

[0191] The difference between this embodiment and Embodiment 1 is that in step (2), rhenium chloride, ruthenium chloride, ammonium molybdate tetrahydrate and ammonium metavanadate are added, and based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 1:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 1:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 1:100; based on the vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanoribbons is 1:100.

[0192] Example 27

[0193] The difference between this embodiment and Embodiment 1 is that in step (2), rhenium chloride, ruthenium chloride, ammonium molybdate tetrahydrate, ammonium metavanadate and cerium nitrate are added, and based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 0.5:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 0.5:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 1:100; based on the vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanoribbons is 1:100; based on the cerium in cerium nitrate, the mass ratio of cerium to titanium dioxide nanoribbons is 1:100.

[0194] Example 28

[0195] The difference between this embodiment and Embodiment 1 is that in step (2), rhenium chloride, ruthenium chloride, ammonium molybdate tetrahydrate, ammonium metavanadate, cerium nitrate and zinc nitrate are added, and based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 0.5:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 0.5:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 0.5:100; based on the vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanoribbons is 0.5:100; based on the cerium in cerium nitrate, the mass ratio of cerium to titanium dioxide nanoribbons is 1:100; based on the zinc in zinc nitrate, the mass ratio of zinc to titanium dioxide nanoribbons is 1:100.

[0196] Example 29

[0197] The difference between this example and Example 1 lies in that in step (2), rhenium chloride, ruthenium chloride, ammonium molybdate tetrahydrate, ammonium metavanadate, cerium nitrate, zinc nitrate, and chromium nitrate are added. Based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanobelts is 0.5:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanobelts is 0.5:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanobelts is 0.5:100; based on the vanadium in ammonium metavanadate, the mass ratio of vanadium to titanium dioxide nanobelts is 0.5:100; based on the cerium in cerium nitrate, the mass ratio of cerium to titanium dioxide nanobelts is 0.5:100; based on the zinc in zinc nitrate, the mass ratio of zinc to titanium dioxide nanobelts is 0.5:100; based on the chromium in chromium nitrate, the mass ratio of chromium to titanium dioxide nanobelts is 1:100.

[0198] Example 30

[0199] The difference between this example and Example 1 lies in that in step (2), based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanobelts is 0.05:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanobelts is 0.05:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanobelts is 0.1:100.

[0200] Example 31

[0201] The difference between this example and Example 1 lies in that in step (2), based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanobelts is 3:100; based on the ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanobelts is 3:100; based on the molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanobelts is 2:100.

[0202] Example 32

[0203] The difference between this example and Example 1 lies in that in step (2), only rhenium chloride is added, and based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanobelts is 0.2:100.

[0204] Example 33

[0205] The difference between this example and Example 1 lies in that in step (2), only rhenium chloride is added, and based on the rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanobelts is 8:100.

[0206] Comparative Example 1

[0207] This comparative example provides a titanium-based catalyst, which includes titanium dioxide nanoribbons with oxygen vacancy defects formed as the main active component. The titanium dioxide nanoribbons are doped with promoter rhenium, promoter ruthenium, and promoter molybdenum, and the mass ratio of promoter rhenium to titanium dioxide nanoribbons is 0.5:100, the mass ratio of promoter ruthenium to titanium dioxide nanoribbons is 1:100, and the mass ratio of promoter molybdenum to titanium dioxide nanoribbons is 2:100.

[0208] The preparation method of the titanium-based catalyst includes the following steps:

[0209] (1) Prepare titanium dioxide nanoribbons with oxygen vacancy defects

[0210] (1.1) Mix 0.2 mol of P25 titanium dioxide powder evenly with 500 mL of 8 M NaOH solution, transfer it to a hydrothermal autoclave with a liner, place the hydrothermal autoclave in an oven, heat it at 160 °C for 36 h for hydrothermal reaction, and filter to remove the residual NaOH solution after the hydrothermal reaction ends to obtain a white sodium titanate solid;

[0211] (1.2) Add the white sodium titanate solid to a 1 M HCl solution containing 0.5 mol of 2-phenylisopropanol, stir for 3 h, and carry out alcohol-assisted ion exchange self-assembly to generate titanic acid nanoribbons;

[0212] (1.3) First wash the titanic acid nanoribbons with deionized water until the pH = 5, then filter, and then place them in an oven to dry at 80 °C to obtain a titanium dioxide nanoribbon precursor;

[0213] (1.4) Bake the titanium dioxide nanoribbon precursor in air at a heating rate of 5 °C / min at 600 °C for 4 h, and naturally cool to room temperature after the baking ends to obtain titanium dioxide nanoribbons;

[0214] (2) Add rhenium chloride, ruthenium chloride, and ammonium molybdate tetrahydrate to a beaker and disperse and dissolve them in 200 mL of deionized water. Then add titanium dioxide nanoribbons. Among them, based on rhenium in rhenium chloride, the mass ratio of rhenium to titanium dioxide nanoribbons is 0.5:100; based on ruthenium in ruthenium chloride, the mass ratio of ruthenium to titanium dioxide nanoribbons is 1:100; based on molybdenum in ammonium molybdate tetrahydrate, the mass ratio of molybdenum to titanium dioxide nanoribbons is 2:100. Ultrasonically disperse for 1 h, then evaporate the solvent at 85 °C to obtain a dry solid. Heat the dry solid in air at a heating rate of 5 °C / min to raise the temperature to 450 °C and bake for 3 h to obtain a powdery titanium-based catalyst. After simply pressing the powdery titanium-based catalyst with a tablet press, crush it to 20-40 mesh to obtain the aforementioned titanium-based catalyst.

[0215] Comparative Example 2

[0216] This comparative example provides a titanium-based catalyst, which is titanium dioxide nanoribbons with oxygen vacancy defects. The preparation method of the titanium-based catalyst includes the following steps:

[0217] (1.1) Mix 0.2 mol of P25 titanium dioxide powder evenly with 500 mL of 8 M NaOH solution, transfer it to a hydrothermal autoclave with a liner, place the hydrothermal autoclave in an oven, heat it at 160 °C for 36 h, and after the hydrothermal reaction ends, filter to remove the residual NaOH solution to obtain a white sodium titanate solid;

[0218] (1.2) Place the white sodium titanate solid in a 1 M HCl solution containing 0.5 mol of 2-phenylisopropanol, stir for 3 h, and perform alcohol-assisted ion-exchange self-assembly to generate titanic acid nanoribbons;

[0219] (1.3) First, wash the titanic acid nanoribbons with deionized water until the pH = 5, then perform suction filtration, and then place them in an oven and dry at 80 °C to obtain a titanium dioxide nanoribbon precursor;

[0220] (1.4) Bake the titanium dioxide nanoribbon precursor in air at 350 °C for 3 h at a heating rate of 5 °C / min, then change the baking atmosphere to argon, and bake in argon at 600 °C for 4 h at a heating rate of 5 °C / min. After the baking ends, naturally cool to room temperature to obtain titanium dioxide nanoribbons. After simply pressing the titanium dioxide nanoribbons with a tablet press, crush them to 20 - 40 mesh to obtain the aforementioned titanium-based catalyst.

[0221] Comparative Example 3

[0222] The difference between this example and Example 1 is that in step (1.2), the amount of 2-phenylisopropanol used is 0.01 mol, and in step (1.4), it is baked in air at 300 °C for 2 h, and then baked in argon at 500 °C for 1 h.

[0223] Comparative Example 4

[0224] The difference between this example and Example 1 is that in step (1.2), the amount of 2-phenylisopropanol used is 2 mol, and in step (1.4), it is baked in air at 450 °C for 4 h, and then baked in argon at 700 °C for 6 h.

[0225] Test Example 1

[0226] Perform SEM testing on the titanium dioxide nanoribbons obtained in Example 1, and the results are as Figure 1 shown. It can be seen from Figure 1 that the width of the titanium dioxide nanoribbons is 80 - 120 nm.

[0227] The titanium dioxide nanobelts obtained in Example 1 were subjected to TEM testing, and the results are as follows Figure 2 shown. It can be seen from Figure 2 that the morphology of the titanium dioxide nanobelts is uniform, and the length of the nanobelts can reach several micrometers.

[0228] Test Example 2

[0229] The titanium dioxide nanobelts with oxygen vacancy defects provided in the above Examples and Comparative Examples were measured for the concentration of oxygen vacancy defects, and the results are shown in Table 1 below.

[0230] 20 g of the titanium-based catalysts provided in the above Examples and Comparative Examples were respectively filled in a fixed-bed reactor. The reaction bed was heated to 50 °C, and an acetonitrile solution of a thioether intermediate ( ), with a mass ratio of acetonitrile to the thioether intermediate of 3:1, was fed into the fixed bed at a rate of 0.5 g / min. At the same time, an aqueous hydrogen peroxide solution (mass concentration of 50 wt%) was fed into the fixed bed at a rate of 0.1 g / min for continuous oxidation to obtain pyraclonil, and the reaction product was detected by liquid chromatography. The concentration of oxygen vacancy defects, the conversion rate of the thioether intermediate, the selectivity of pyraclonil, and the thickness of the titanium dioxide nanobelts were measured, and the results are shown in Table 1.

[0231] 1. The method for measuring the concentration of oxygen vacancy defects in the titanium dioxide nanobelts is as follows: Using thionine (TH) as a titrant, the surface oxygen vacancy concentration was measured by an electronic titration method. 10 mg of the titanium dioxide nanobelts were suspended in 10 mL of deionized water, and then added to 2 mL of an aqueous thionine solution (0.1 mM). The suspension was filtered and the ultraviolet-visible absorption spectrum of the filtrate at 602.5 nm was measured quickly. Assuming that one oxygen vacancy (V o ) site is accompanied by two Ti 3+ (Ti 3+ -V o -Ti 3+ ), the titration principle is as follows: TH exists in the form of a dark blue monovalent cation and is reduced to a colorless anion (TH 2- ) form in two steps. Based on this electronic titration method, the concentration of oxygen vacancy defects in the titanium dioxide nanobelts can be calculated.

[0232] 2Ti 3+ + 2TH (blue) → 2Ti 4+ + 2TH - (1)

[0233] 2TH - = TH 2-( colorless) + TH (2)

[0234] 2. The calculation method for the conversion rate of the thioether intermediate is as follows:

[0235] Conversion rate (%) = (1 - remaining moles of thioether intermediate / moles of thioether intermediate charged) × 100.

[0236] 3. The calculation method for the selectivity of pyroxasulfone is as follows:

[0237] Selectivity (%) = [molar concentration of pyroxasulfone / (molar concentration of pyroxasulfone + molar concentration of other products)] × 100.

[0238] 4. The thickness of the titanium dioxide nanobelts is measured using an atomic force microscope.

[0239] Table 1

[0240]

[0241] It can be seen from the experimental results of Examples 1 - 8 and Comparative Examples 3 - 4 that when the main active component of the titanium-based catalyst is titanium dioxide nanobelts and the concentration of oxygen vacancy defects in the titanium dioxide nanobelts is 5 - 20 μmol / g, in the reaction of continuously oxidizing thioether intermediates to synthesize pyroxasulfone in a fixed bed, the conversion rate of thioether intermediates reaches 100%, and the selectivity of pyroxasulfone is relatively high. When the concentration of oxygen vacancy defects is too small, the number of surface defect sites is too small, which is not conducive to the adsorption and activation of reactants, resulting in a significant decrease in the selectivity of pyroxasulfone; when the concentration of oxygen vacancy defects is too large, the adsorption ability for reactants is too strong, which is not conducive to the desorption of products, resulting in the selectivity of pyroxasulfone no longer increasing and even slightly decreasing.

[0242] It can be seen from the experimental results of Example 1, Examples 9 - 29 and Comparative Example 2 that when the mass ratio of the promoter metal component M to the titanium dioxide nanobelts is 0.5 - 5:100, regardless of whether the promoter metal component M is a single metal or multiple metals, such as the number of types of promoter metal M being one, two, three, four, five, six or seven, as long as the total mass of the promoter metal and the mass ratio of the titanium dioxide nanobelts is 0.5 - 5:100, then in the reaction of continuously oxidizing thioether intermediates to synthesize pyroxasulfone in a fixed bed using this titanium-based catalyst, both the conversion rate of thioether intermediates and the selectivity of pyroxasulfone are excellent. And it can be known from the experimental results of Examples 30 - 33 and Comparative Example 2 that when the mass ratio of the promoter metal component M to the titanium dioxide nanobelts is too small, due to the decrease in the content of the promoter metal, the number of active sites decreases, resulting in a decrease in the selectivity of pyroxasulfone. When no promoter metal component M is doped, the selectivity of pyroxasulfone further decreases. When the mass ratio of the promoter metal component M to the titanium dioxide nanobelts is too large, the content of the promoter metal increases, resulting in the selectivity of pyroxasulfone no longer increasing and even decreasing.

[0243] From the experimental results of Example 1 and Comparative Example 1, it can be seen that when the titanium dioxide nanoribbon precursor is first subjected to oxygen-containing calcination in an oxygen-containing atmosphere and then subjected to inert calcination in an inert atmosphere in step (1.4), the selectivity of oxasulfuron is relatively high. When the calcination atmosphere is only an oxygen-containing atmosphere (air), the selectivity of oxasulfuron is significantly reduced, indicating that the calcination under two different atmosphere conditions can further promote the formation of oxygen vacancy defects (V o ) and thus improve the selectivity of oxasulfuron.

[0244] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0245] The titanium-based catalyst provided in this application uses titanium dioxide nanoribbons with oxygen vacancy defects (V o ) as the main active component, and a promoter metal component M is doped in the titanium dioxide nanoribbons. Due to the loss of lattice oxygen in the titanium dioxide nanoribbons, some tetravalent Ti 4+ is reduced to generate Ti 3+ , and adjacent Ti 3+ forms Ti o -V 3+ -Ti o surface defect sites with oxygen vacancies (V 3+ ). The titanium dioxide nanoribbons have the characteristics of a large specific surface area and sufficient exposure of active sites. In the reaction of synthesizing oxasulfuron by sulfide oxidation, the coordinatively unsaturated Ti 3+ -V o -Ti 3+ surface defect sites can enhance the adsorption and activation of reactants. Adjacent Ti 3+ can form stable Ti 3+ -S-Ti 3+ and Ti 3+ -O-Ti 3+ bonds with sulfide and hydrogen peroxide, thereby improving the reaction kinetics of the oxidation process. And the titanium dioxide nanoribbons have good wettability and ductility, which helps the diffusion and transport of reactant molecules, thus improving the reaction rate.

[0246] In addition, due to the higher energy of the Ti 3+ -V o -Ti 3+ surface defect sites, the oxygen vacancy (V o ) can have an electronic interaction with the promoter metal ions. Through Ti 3+ -V o -Ti 3+The electron localization centers formed by the surface defect sites anchor the promoter metal component M, improving the dispersion and stability of the promoter metal component M on the titanium dioxide nanoribbons, thereby providing more reactive sites. At the same time, it also extends the service life of the titanium-based catalyst, which is beneficial to the efficient and stable oxidation of thioether to sulfone in the reaction.

[0247] In the reaction for oxidizing thioether intermediates to synthesize pyraoxystrobin using the titanium-based catalyst provided by this application in a fixed bed, the raw material conversion rate reaches 100%, the product selectivity is relatively high, and the continuous production of pyraoxystrobin is also realized.

[0248] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A titanium-based catalyst for synthesizing sulfonepyraclostrobin, characterized in that: include: A main active component and an auxiliary metal component M doped in the main active component; The main active component is titanium dioxide nanobelts, and the titanium dioxide nanobelts form oxygen vacancy defects, and the concentration of the oxygen vacancy defects is 5-20 μmol / g; the auxiliary metal component M includes at least one of Re, Ru, Mo, V, Ce, Zn and Cr; In the titanium-based catalyst, the mass ratio of the auxiliary metal component M to the titanium dioxide nanobelt is 0.5-5:100; The preparation method of the titanium-based catalyst comprises the following steps: Step S1, preparing titanium dioxide nanobelts with oxygen vacancy defects; Step S2, mixing the titanium dioxide nanobelt, M source and water, and then sequentially performing a first drying and a first calcination to obtain a titanium-based catalyst; Wherein, the step S1 comprises: Step S11, mixing a titanium source with an alkaline solution, and performing a hydrothermal reaction to obtain titanate; Step S12, mixing the titanate, alcohol and acidic solution to perform ion exchange to obtain titanate nanobelts; Step S13, washing and second drying the titanate nanobelts in sequence to obtain a titanium dioxide nanobelt precursor; Step S14, performing a second calcination on the titanium dioxide nanobelt precursor to obtain the titanium dioxide nanobelt; In the step S14, the second calcination includes first performing oxygen-containing calcination in an oxygen-containing atmosphere and then performing inert calcination in an inert atmosphere.

2. The titanium-based catalyst for synthesizing sulfonepyraclostrobin according to claim 1, characterized in that: The titanium dioxide nanobelt is in the shape of a nanobelt and has a thickness of 1 to 5 nm.

3. The titanium-based catalyst for synthesizing sulfonepyraclostrobin according to claim 1, characterized in that: In the step S11, the titanium source is at least one of titanium dioxide, titanyl sulfate and P25 titanium dioxide; And / or, the alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution; And / or, the concentration of the alkaline solution is 1-20 mol / L; And / or, the molar ratio of the titanium source to the alkaline solution is 1:2-50; And / or, the temperature of the hydrothermal reaction is 120-200° C., and the time of the hydrothermal reaction is 12-96 hours.

4. The titanium-based catalyst for synthesizing sulfonepyraclostrobin according to claim 1, characterized in that: In step S12, the concentration of the acidic solution is 0.01-5 mol / L; And / or, the acidic solution includes hydrochloric acid solution and / or nitric acid solution; And / or, the alcohol is at least one of aromatic alcohols having 6 to 15 carbon atoms; And / or, the molar ratio of the alcohol to the titanium source is 0.1-10:

1.

5. The titanium-based catalyst for synthesizing sulfonepyraclostrobin according to claim 1, characterized in that: The oxygen-containing atmosphere includes air and / or oxygen; the inert atmosphere includes argon and / or nitrogen.

6. The titanium-based catalyst for synthesizing sulfonepyraclostrobin according to claim 1, characterized in that: In the step S2, the temperature of the first calcination is 300-600° C., and the time of the first calcination is 2-4 hours; And / or, the M source includes at least one of a Re source, a Ru source, a Mo source, a V source, a Ce source, a Zn source and a Cr source; wherein the Re source is selected from at least one of rhenium chloride, perrhenic acid and ammonium perrhenate; the Ru source is selected from ruthenium chloride and / or ruthenium acetate; the Mo source is selected from at least one of ammonium molybdate tetrahydrate, molybdenum chloride, phosphomolybdic acid and ammonium phosphomolybdate; the V source is selected from ammonium metavanadate and / or vanadium trichloride; the Ce source is selected from at least one of cerium nitrate, cerium chloride, cerium sulfate and cerium acetate; the Zn source is selected from at least one of zinc nitrate, zinc chloride, zinc sulfate and zinc acetate; the Cr source is selected from at least one of chromium nitrate, chromium sulfate and chromium acetate.

7. A method for synthesizing sulfonepyraclostrobin, characterized in that: The synthesis method comprises: an oxidation reaction of a sulfide intermediate of formula (A) and hydrogen peroxide under the action of a catalyst to obtain the sulfonepyraclostrobin. The synthesis schematic diagram of the sulfonepyraclostrobin is as follows: ； Wherein, the catalyst is the titanium-based catalyst according to any one of claims 1 to 6; the catalyst is loaded in a fixed bed.

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