Metal peroxo complex molecular catalysts, methods of making and using the same, and continuous process for the synthesis of pyroxasulfone

Abstract

The application provides a metal peroxide complex molecule catalyst and a preparation method and application thereof, and a continuous synthesis method of metrafenone. The metal peroxide complex molecule catalyst is prepared through a series of operation steps, transition metal ion centers, organic ligands and metal-peroxide bridge (M-O-O-M) structures are introduced into the prepared metal peroxide complex molecule catalyst, and the prepared metal peroxide complex molecule catalyst is used for oxidizing sulfide into sulfone under the synergistic effect between the above structures, and has excellent selectivity and catalytic efficiency. Especially, the metal peroxide complex molecule catalyst is used for catalyzing 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole to oxidize and synthesize metrafenone, the reaction efficiency, selectivity and safety of the oxidation reaction can be effectively improved, and therefore the preparation cost of metrafenone is further reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fine chemical technology, in particular to a metal peroxide complex molecular catalyst, a preparation method and application thereof, and a continuous synthesis method of pyroxasulfone. BACKGROUND

[0002] Pyroxasulfone is a new type of broad-spectrum, high-activity pre-emergence soil treatment agent developed by Japan's Syngenta Company, belonging to the isoxazole herbicide. Its molecular formula is: C 12 H 14 F5N3O4S, 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 the compound is as follows:

[0003] .

[0004] Pyroxasulfone is designed for efficient pre-emergence soil treatment in crop fields, showing excellent compatibility and safety for a variety of crops including corn, peanuts, rapeseed, wheat, cotton, and legumes. Its mechanism of action is similar to that of acetochlor and S-metolachlor herbicides, which are absorbed by weed seedlings and young shoots, thereby inhibiting the early growth of seedlings, destroying meristems and coleoptiles. In particular, it exhibits extremely high biological activity as a potential inhibitor of very long chain fatty acid (VLCFA, with a carbon chain length of C20 to C30) biosynthesis in plant bodies. Compared with traditional herbicides, pyroxasulfone has the advantages of low unit area application amount and long herbicidal persistence, and can effectively control grass weeds such as Digitaria, Cynodon, Echinochloa, and broadleaf weeds such as Solanum, Amaranthus, Abutilon, and Datura.

[0005] The synthesis of pyroxasulfone involves a series of fine chemical reactions. Among them, the process of oxidizing sulfide (specifically 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylsulfanyl]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) to form sulfone is a key step in the entire synthesis route and a bottleneck in the synthesis technology of pyroxasulfone. This key step requires the selective oxidation of sulfide under the joint action of catalyst and oxidant (such as hydrogen peroxide) to form the target product. However, achieving high selectivity conversion of sulfide to sulfone is a challenge in synthetic chemistry, as this process is prone to produce sulfoxide and peroxide impurities, which will adversely affect the selectivity and production efficiency of the product. Among them, the reaction equation of the synthesis step of oxidizing sulfide to form sulfone in the synthesis process of pyroxasulfone is:

[0006] .

[0007] Patent CN 111574511 A discloses a synthesis method of metrafenone and its application. The catalyst used for the oxidation of sulfide in this patent is sodium tungstate dihydrate. The sulfide (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) is oxidized in concentrated sulfuric acid and hydrogen peroxide solution with sodium tungstate dihydrate as catalyst. After 6 hours of reaction, the yield of metrafenone is only 90%. Patent CN 118307533 A discloses a preparation method of metrafenone. This patent also uses sodium tungstate dihydrate as the catalyst for the oxidation of sulfide. The oxidation reaction is carried out at 45°C for 7 hours, and the yield of metrafenone is 88%. Patent CN 117794925 A discloses a preparation method of metrafenone. This patent uses sodium tungstate or its dihydrate as the catalyst for the oxidation of sulfide. The oxidation reaction is carried out in an organic acid solvent and with sufficient hydrogen peroxide for 7 hours, and the yield of metrafenone is 87.6%.

[0008] Currently, the main catalyst for the oxidation of sulfide to form sulfone is homogeneous tungsten catalyst, such as tungstic acid, various tungstate salts (such as sodium tungstate dihydrate), tungsten oxide, phosphotungstic acid and its salts. Although tungsten catalyst can catalyze the oxidation of sulfide in batch reaction kettle, this scheme has significant shortcomings. For example: cost problem: the use of tungsten catalyst is expensive, especially considering its demand in large-scale production, which significantly increases the production cost; low reaction efficiency: tungsten catalyst is mostly suitable for batch reaction, which not only prolongs the reaction period, but also limits the continuity and production efficiency of the reaction. A longer reaction period means lower production efficiency and higher energy consumption; by-product problem: the oxidation of sulfide under the action of tungsten catalyst is often accompanied by the generation of sulfoxide and peroxide impurities, which not only reduces the yield of target metrafenone, but also affects its purity; reaction condition control problem: in traditional kettle type reactor, due to uneven mass transfer and local overheating phenomenon, it is difficult to accurately control the reaction conditions, resulting in unstable catalyst activity, difficult control of impurity content, and thus affecting the quality of the product; environmental protection and safety problem: the use and disposal of tungsten catalyst brings additional environmental pressure and safety problem. The tungsten-containing waste liquid generated after the reaction needs special treatment steps to avoid heavy metal pollution, which not only increases the production cost, but also poses a potential threat to the environment.

[0009] In summary, finding a catalyst that can overcome the above limitations, further improving the reaction efficiency, selectivity and safety of the oxidation of sulfide to form sulfone, and reducing the cost of the catalyst, has become a problem that needs to be solved in the further development of the field of metrafenone synthesis. SUMMARY

[0010] The main purpose of the present application is to provide a metal peroxide complex molecule catalyst, a preparation method and application thereof, and a continuous synthesis method of mefenpyr-diethyl, aiming to further improve the reaction efficiency, selectivity and safety of sulfide oxidation to form sulfone, while reducing the synthesis cost of the catalyst and promoting the further development of the synthesis technology of mefenpyr-diethyl.

[0011] To solve the above problems, the present application provides a preparation method of a metal peroxide complex molecule catalyst, which comprises the following steps: first mixing a soluble metal salt with a solvent to obtain a first solution; wherein the metal ion in the soluble metal salt is a transition metal ion; second mixing an organic ligand with the first solution to obtain a mixed solution; heating the mixed solution to perform a first reaction to obtain a second solution containing a metal organic complex; adding a first oxidant to the second solution to perform a second reaction to generate a metal peroxide complex molecule catalyst; wherein the first oxidant is used to provide at least one of superoxide anion, peroxide bond, hydroxyl radical, singlet oxygen or ozone, so that the metal organic complex generates a metal peroxide complex molecule catalyst containing a metal peroxide bridge bond.

[0012] Further, the organic ligand contains one or more of oxygen atoms, nitrogen atoms, hydroxyl groups and carboxyl groups; and / or, the organic ligand is selected from one or more of glycine, triethanolamine, ethylenediamine, porphyrin, bipyridine, imidazole, oxalic acid, citric acid, tartaric acid, malic acid and ethylenediaminetetraacetic acid; and / or, the transition metal ion is at least one of the fourth period, the fifth period, the sixth period and the lanthanide series in the periodic table of elements; and / or, the transition metal ion is at least one of titanium ion, vanadium ion, molybdenum ion, rhenium ion, zinc ion and cerium ion; and / or, the soluble metal salt is selected from one or more of titanium sulfate, titanyl sulfate, titanium potassium oxalate, ammonium metavanadate, sodium metavanadate, vanadyl trichloride, ammonium molybdate, ammonium heptamolybdate tetrahydrate, sodium molybdate, potassium molybdate, molybdenum chloride, phosphomolybdic acid, ammonium phosphomolybdate, rhenium chloride, zinc nitrate, zinc chloride, zinc sulfate, cerium nitrate, cerium chloride and cerium sulfate.

[0013] Further, the first oxidant is at least one of ozone, hydrogen peroxide and persulfate.

[0014] Further, before the first reaction, the preparation method further comprises: adjusting the pH of the mixed solution; and / or, adjusting the pH of the mixed solution to 2-6; and / or, the solvent used for adjusting the pH is at least one of an inorganic acid aqueous solution or an organic base; and / or, the inorganic acid aqueous solution is a hydrochloric acid aqueous solution and / or a nitric acid aqueous solution; preferably, the concentration of the inorganic acid aqueous solution is 0.1-12 mol / L; and / or, the organic base is selected from one or more of triethylamine, propylamine, isopropylamine, 1,3-propanediamine, 1,2-propanediamine, tripropylamine, butylamine, isobutylamine and tert-butylamine; and / or, the molar ratio of the metal ion to the organic ligand in the first solution is 1:(1-3); and / or, the temperature of the first mixing is 30-60℃, and the time is 0.5-1 h; and / or, the temperature of the first reaction is 30-80℃, and the time is 1-10 h.

[0015] Further, the temperature of the second reaction is 5-25℃, and the time is 1-4 h; and / or, the molar ratio of the first oxidant to the metal organic complex is (2-15):1; and / or, the solvent is water, or a mixture of water and acetonitrile.

[0016] Further, the concentration of the transition metal ion in the first solution is 0.01-0.1 mol / L; and / or, the temperature of the first mixing is 30-60℃, and the time is 0.5-1 h.

[0017] According to the second aspect of the present application, a metal peroxo complex molecule catalyst is also provided, which is prepared by the above preparation method.

[0018] According to the third aspect of the present application, the above metal peroxo complex molecule catalyst is also provided, which is used for catalyzing 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole to prepare synthetic mefenpyr-diethyl; and / or, the preparation is carried out in a tank reactor or a coil reactor.

[0019] According to the fourth aspect of the present application, a continuous synthesis method of mefenpyr-diethyl is also provided, which comprises the following steps: mixing 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole with the above metal peroxo complex molecule catalyst to obtain a mixed material; continuously feeding the mixed material and a second oxidant into a coil reactor to carry out an oxidation reaction, so as to obtain mefenpyr-diethyl.

[0020] Further, the molar ratio of the metal peroxo complex molecule catalyst to 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole is (0.05-0.1):1; and / or, the molar ratio of the second oxidizing agent to 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole is (2-5):1.

[0021] Further, the temperature of the oxidation reaction is 45-60°C, and the time is 30-120 min; and / or, the second oxidizing agent is hydrogen peroxide.

[0022] The metal peroxo complex molecule catalyst prepared by the preparation method provided in the present application has excellent selectivity and catalytic efficiency when used as a catalyst for the oxidation of sulfides into sulfones under the synergistic effect of the transition metal ion center, organic ligand, and metal-peroxide bridge (M-O-O-M) structure in the metal peroxo complex molecule catalyst. The use of the metal peroxo complex molecule catalyst in the synthesis of metrafenone can effectively improve the reaction efficiency, selectivity, and safety of the oxidation reaction, thereby facilitating the further reduction of the preparation cost of metrafenone. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0024] As described in the background section, the catalyst commonly used in the prior art for the oxidation of sulfides into sulfones is a homogeneous tungsten catalyst. Although the tungsten catalyst can catalyze the oxidation of sulfides in a batch reaction kettle, this scheme has significant disadvantages, such as cost problems, low reaction efficiency, byproduct problems, reaction condition control difficulties, and environmental protection and safety problems. Therefore, it is urgent to develop a catalyst that can overcome the above limitations, improve the reaction efficiency, selectivity, and safety of the oxidation of sulfides into sulfones, and reduce the cost, which is a problem to be solved in the further development of the field of metrafenone synthesis.

[0025] To solve the above problems, the application provides a preparation method of a metal peroxo complex molecule catalyst, which comprises the following steps: first mixing a soluble metal salt with a solvent to obtain a first solution; wherein the metal ion in the soluble metal salt is a transition metal ion; second mixing an organic ligand with the first solution to obtain a mixed solution; heating the mixed solution to perform a first reaction to obtain a second solution containing a metal organic complex; adding a first oxidant to the second solution to perform a second reaction to generate the metal peroxo complex molecule catalyst; wherein the first oxidant is used to provide at least one of a superoxide anion, a peroxide bond, a hydroxyl radical, singlet oxygen or ozone, so that the metal organic complex generates the metal peroxo complex molecule catalyst containing a metal peroxo bridge bond.

[0026] Specifically, in the preparation method of the metal peroxo complex molecule catalyst, the soluble metal salt is first fully dissolved in the solvent to obtain the first solution; wherein the metal ion in the soluble metal salt is a transition metal ion (such as titanium, vanadium, molybdenum, etc.). The transition metal ion has a variable oxidation state and electronic structure, and when these metal ions act as central atoms in coordination chemistry, they can form stable complexes with different types of organic ligands, and the electronic transfer ability of the transition metal ion itself is conducive to the subsequent generation of the metal peroxo complex molecule catalyst containing the peroxo bridge bond. Then, the organic ligand is fully mixed with the first solution, and the obtained mixed solution is heated to perform a first reaction to obtain a second solution containing a metal organic complex. The above operation process can fully complex the transition metal ion in the first solution with the organic ligand to form a second solution containing a stable metal organic complex. Finally, the first oxidant is added to the second solution to perform a second reaction to generate the metal peroxo complex molecule catalyst. The second reaction process can initiate the formation of a metal-peroxo bridge bond (M-O-O-M) under the action of an oxidant capable of providing a superoxide anion, a peroxide bond, a hydroxyl radical, singlet oxygen or ozone, and finally obtain the metal peroxo complex molecule catalyst. The metal peroxo complex molecule catalyst prepared by the preparation method described in the application contains a transition metal ion center, an organic ligand and a metal-peroxo bridge bond (M-O-O-M), and when it is used as a catalyst in the reaction process of oxidizing a sulfide to a sulfone, it can effectively improve the reaction efficiency, selectivity and safety of the oxidation reaction. The reasons may include the following aspects:

[0027] First, in the reaction of oxidizing sulfide to sulfone, the oxidant participating in the reaction process usually further improves its oxidative activity in the presence of a catalyst. The peroxide bridge bond in the metal peroxide complex molecular catalyst in this application is activated due to the Lewis acidity of the metal and has electrophilicity. It can act as an electrophilic reagent to attack the sulfur atom in the electron-rich sulfide, thereby transferring the electrophilic oxygen atom to the substrate molecule. At the same time, the metal peroxide complex molecular catalyst can induce the oxidant (such as molecular oxygen, hydrogen peroxide or persulfate, etc.) to generate more active reactive oxygen species (such as singlet oxygen ( 1 O2), superoxide anion (·O2 − ), hydroxyl radicals (·OH), etc., to continuously generate peroxide groups. The peroxide groups in the metal peroxide complex molecular catalyst act as a "bridge" for oxygen transfer, lowering the reaction energy barrier for the direct reaction between the oxidant and the substrate sulfide, thereby accelerating the reaction kinetics of the sulfide oxidation process. The dynamic evolution of the metal center in the catalyst, its surrounding coordination environment, and its electrons further effectively stabilizes the activity and reaction stability of these highly reactive oxygen species, thereby enhancing the catalyst's catalytic activity and the efficiency of sulfide oxidation to sulfone, further reducing the occurrence of side reactions.

[0028] Secondly, the peroxide bridge bond (MOOM) in the metal peroxide complex molecular catalyst can heterolytically cleave to generate a high-valent metal oxide species (M=O). The cracked peroxide bridge bond has a stronger electrophilicity, enabling the selective oxidation of electron-rich sulfide substrates without affecting other groups in the molecule. The organic ligand in the metal peroxide complex molecular catalyst can further stabilize the high-valent metal intermediate, regulate the electronic structure, or provide a hydrogen bond network, thereby enhancing the catalytic activity and selectivity of the metal peroxide complex molecular catalyst in the oxidation of sulfides to sulfones.

[0029] Third, metal peroxide complex molecular catalysts regulate the breakage of the -OO- bond in the peroxide bridge (MOOM) and the generation of active oxygen species through the synergistic effect of the metal center and the ligand, and have both high selectivity and high efficiency, thereby achieving a better catalytic effect even at a low catalyst usage level, thereby further reducing the cost of catalyst use by reducing the amount of catalyst used.

[0030] In summary, the metal peroxide complex molecular catalyst prepared by the preparation method provided in the present application, under the synergistic effect between the transition metal ion center, organic ligand and metal-peroxide bridge (MOOM) structure, is used as a catalyst for the oxidation of sulfide to sulfone, and has excellent selectivity and catalytic efficiency. Its use in the synthesis of sulfonepyraclostrobin can effectively improve the reaction efficiency, selectivity and safety of the oxidation reaction, thereby helping to further reduce the preparation cost of sulfonepyraclostrobin.

[0031] In a preferred embodiment, the organic ligand contains one or more of an oxygen atom, a nitrogen atom, a hydroxyl group and a carboxyl group. Organic ligands having the above elements or functional groups can better react with transition metal ions to form coordination bonds, thereby making the metal peroxide complex molecular catalyst have better catalytic activity and reaction efficiency. Preferably, the organic ligand is selected from one or more of glycine, triethanolamine, ethylenediamine, porphyrin, bipyridine, imidazole, oxalic acid, citric acid, tartaric acid, malic acid and ethylenediaminetetraacetic acid. Using the above specific organic ligands for the preparation of the metal peroxide complex molecular catalyst can make the performance of the prepared catalyst better. More preferably, the organic ligand is selected from one or more of glycine, triethanolamine, ethylenediamine, citric acid, bipyridine, tartaric acid, malic acid, imidazole and ethylenediaminetetraacetic acid. The above organic ligands can further improve the performance of the prepared catalyst.

[0032] Preferably, the transition metal ion is at least one of the fourth, fifth, sixth and lanthanide periods in the periodic table. Using metal ions in the fourth, fifth, sixth and lanthanide periods in the periodic table as the active center of the metal peroxide complex molecular catalyst can better coordinate with the organic ligand, and the performance of the generated metal peroxide bridge bond will also be better, thereby making the catalytic performance of the obtained metal peroxide complex molecular catalyst better. Preferably, the transition metal is selected from titanium ions (such as Ti 3+ 、Ti 4+ ), vanadium ions (such as V 3+ 、V 4+ 、V 5+ ), molybdenum ions (Mo 4+ 、Mo 5+ 、Mo 6+ ), rhenium ions (Re 3+ 、Re 6+ 、Re 7+ ), zinc ions (Zn 2+ ) and cerium ions (Ce 3+ 、Ce 4+ ) at least one of. Preferably, the transition metal is selected from Ti 4+ 、V 5+ 、Mo6+ Re 3+ Zn 2+ and Ce 3+ The above transition metal ions are used as the metal center of the metal- peroxo complex molecular catalyst, and the comprehensive performance of the obtained metal- peroxo complex molecular catalyst is better. By way of example but not limitation, the soluble metal salt is selected from one or more of titanium sulfate, titanyl sulfate, potassium titanyl oxalate, ammonium metavanadate, sodium metavanadate, vanadyl trichloride, ammonium molybdate, ammonium heptamolybdate tetrahydrate, sodium molybdate, potassium molybdate, molybdenum chloride, phosphomolybdic acid, ammonium phosphomolybdate, rhenium chloride, zinc nitrate, zinc chloride, zinc sulfate, cerium nitrate, cerium chloride, and cerium sulfate. The use of the above soluble metal salt for the preparation of the metal-peroxo complex molecular catalyst can further improve the catalytic performance of the metal-peroxo complex molecular catalyst.

[0033] In a preferred embodiment, the first oxidizing agent is at least one of ozone, hydrogen peroxide, and persulfate. The use of the above oxidizing agent in the second reaction can enable the metal-organic complex in the second solution to form a metal-peroxo bridge bond better, so that the obtained metal-peroxo complex molecular catalyst has better catalytic activity and selectivity.

[0034] In a preferred embodiment, before the first reaction, the mixed solution is further subjected to pH adjustment; preferably, the pH of the mixed solution is adjusted to 2-6. The adjustment of the pH of the mixed solution before the first reaction, especially the control of the pH in the above range after adjustment, can better regulate the protonation state of the organic ligand, enhance the coordination ability of the ligand, and at the same time, further inhibit the hydrolysis of the transition metal ion and stabilize the metal valence state, to generate a more stable metal-organic complex. Preferably, the solvent used for adjusting the pH is at least one of an inorganic acid aqueous solution or an organic base; preferably, the inorganic acid aqueous solution is an aqueous hydrochloric acid solution and / or an aqueous nitric acid solution; preferably, the concentration of the inorganic acid aqueous solution is 0.1-12 mol / L; preferably, the organic base is selected from one or more of triethylamine, propylamine, isopropylamine, 1,3-propanediamine, 1,2-propanediamine, tripropylamine, butylamine, isobutylamine, and tert-butylamine. The use of the above substances for adjusting the pH of the mixed solution has a better effect.

[0035] Preferably, the molar ratio of metal ions to organic ligands in the first solution is 1:(1-3). Controlling the molar ratio of metal ions to organic ligands in the first solution within the above range can achieve complete coordination of metal ions, and meanwhile, the metal organic complex formed has better stability. Preferably, the temperature of the second mixing is 30-60°C, and the time is 0.5-1 h; preferably, the temperature of the first reaction is 30-80°C, and the time is 1-10 h. Controlling the temperature and time of the second mixing and the temperature and time of the first reaction within the above range can make the complexation reaction of the organic ligands and the transition metal ions better, so that the metal organic complex in the system can be formed more fully.

[0036] In a preferred embodiment, the temperature of the second reaction is 5-25°C, and the time is 1-4 h; preferably, the molar ratio of the first oxidant to the metal organic complex is (2-15):1. Controlling the temperature, time of the second reaction, and the molar ratio of the first oxidant to the metal organic complex within the above range can make the performance of the metal peroxo complex molecular catalyst better. Preferably, the solvent is water, or a mixture of water and acetonitrile; preferably, the volume ratio of water to acetonitrile is (1-10):1. Using the above-mentioned soluble metal salt and the solvent to prepare the metal peroxo complex molecular catalyst can further improve the catalytic selectivity and catalytic efficiency of the metal peroxo complex molecular catalyst prepared.

[0037] In a preferred embodiment, the concentration of the transition metal ions in the first solution is 0.01-0.1 mol / L; preferably, the temperature of the first mixing is 30-60°C, and the time is 0.5-1 h. Controlling the concentration of the transition metal ions in the first solution and the temperature and time of the first mixing within the above range can make the metal ions mix better, and be more conducive to the generation of the metal peroxo complex molecular catalyst.

[0038] According to another aspect of the present application, there is also provided a metal peroxo complex molecular catalyst prepared by the above preparation method.

[0039] According to a third aspect of the present application, there is also provided an application of the above metal peroxo complex molecular catalyst. The above metal peroxo complex molecular catalyst is used to catalyze the preparation of synthetic cloquintocet-mexyl from 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole; preferably, the preparation is carried out in a tank reactor or a coil reactor. Using the above catalyst to catalyze the synthesis of cloquintocet-mexyl has good reaction effect, whether in a tank reactor or in a coil reactor.

[0040] According to the fourth aspect of the present application, there is also provided a continuous method for synthesizing metrafenone, comprising the following steps: mixing 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole and a metal peroxo complex molecular catalyst to obtain a mixture; continuously feeding the mixture and a second oxidant into a continuous coil reactor to perform an oxidation reaction to obtain metrafenone.

[0041] The metal peroxo complex molecular catalyst prepared in the present application and the second oxidant can jointly oxidize the sulfide intermediate 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole to metrafenone. Under the action of the metal peroxo complex molecular catalyst provided in the present application, the reaction has better catalytic selectivity and catalytic efficiency. In addition, the reaction of oxidizing the sulfide to metrafenone is an exothermic reaction, and the reaction process needs the participation of a second oxidant (such as hydrogen peroxide). The above-mentioned oxidation reaction is performed in a continuous coil reactor, which not only has good heat and mass transfer effect, but also can more accurately control the reaction temperature, effectively avoiding the decomposition of the second oxidant (such as hydrogen peroxide) caused by local overheating, thereby making the reaction process more secure. In addition, the above-mentioned reaction is performed in a coil reactor, which not only can further improve the reaction yield and selectivity, but also can realize continuous production, thereby further reducing the preparation cost of metrafenone.

[0042] In a preferred embodiment, the molar ratio of the metal peroxo complex molecular catalyst to 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole is (0.05-0.1):1; preferably, the molar ratio of the second oxidizing agent to 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole is (2-5):1. In the process of synthesizing pyroxasulfone, controlling the molar ratio of the metal peroxo complex molecular catalyst to the sulfide intermediate 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole and the molar ratio of the second oxidizing agent to 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole within the above ranges can make the synthesis of pyroxasulfone more efficient, and the selectivity and conversion rate better. Preferably, the temperature of the oxidation reaction is 45-60°C, and the time is 30-120 min. Controlling the temperature and time of the above oxidation reaction within the above ranges can make the oxidation reaction more complete. Preferably, the second oxidizing agent is hydrogen peroxide. Using the above type of second oxidizing agent for the oxidation reaction can further improve the reaction efficiency and reaction yield.

[0043] The application will be further described in detail below in conjunction with specific examples, which cannot be understood as limiting the scope of the application claimed.

[0044] Example 1

[0045] (1) Preparation of metal peroxo complex molecular catalyst

[0046] 0.01 mol of potassium titanium oxalate (K2[TiO(C2O4)2]·2H2O) was dissolved in 1 L of deionized water, stirred at 30°C for 1 h, and prepared into a potassium titanium oxalate solution with a transition metal ion concentration of 0.01 mol / L. 0.03 mol of glycine organic ligand was dissolved in the above potassium titanium oxalate solution, and the mixture was stirred at the temperature for 0.5 h to obtain a mixed solution; after adjusting the pH of the mixed solution to 6 with triethylamine, the obtained solution was stirred and reacted at 60°C for 5 h to obtain a second solution containing a metal organic complex. After cooling the obtained second solution to 25°C, 0.02 mol of 6% mass fraction hydrogen peroxide aqueous solution was slowly added thereto and continuously stirred for 4 h to obtain a metal peroxo complex molecular catalyst.

[0047] (2) Synthesis of pyroxasulfone

[0048] The metal peroxide complex molecular catalyst synthesis solution prepared above was mixed without separation. A catalyst system containing 0.01 mol of the metal peroxide complex was mixed with a reaction system containing 0.2 mol of a thioether intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) to obtain a mixed material. The mixed material and a hydrogen peroxide solution (oxidant) were introduced into a continuous coil reactor for oxidation to produce a sulfonepyrazoline reaction solution. The hydrogen peroxide solution had a mass concentration of 50% and was introduced at a flow rate of 0.2 g / min. The mixed material was introduced at a flow rate of 6.0 g / min. The molar ratio of the oxidant to the thioether intermediate was 5:1. The oxidation reaction temperature was 60°C and the reaction time was 30 minutes.

[0049] The obtained sulfonepyraclostrobin reaction solution was tested for relevant properties by liquid chromatography, and the results are shown in Table 1.

[0050] Example 2

[0051] 0.1 mol of ammonium metavanadate (NH₄VO₃) was dissolved in 1 L of deionized water and stirred at 60°C for 0.5 h to prepare an ammonium metavanadate solution with a transition metal ion concentration of 0.1 mol / L. 0.1 mol of triethanolamine (a ligand) was dissolved in the ammonium metavanadate solution and stirred at the same temperature for 0.5 h to obtain a mixed solution. The pH of the mixed solution was adjusted to 5 with 12 mol / L hydrochloric acid aqueous solution, and the resulting solution was stirred at 80°C for 1 h to obtain a second solution containing the metal-organic complex. After cooling the resulting second solution to 5°C, 1.5 mol of a 50% hydrogen peroxide solution was slowly added and stirred for 1 h to obtain the metal peroxide complex molecular catalyst.

[0052] (2) Synthesis of sulfonepyraclostrobin

[0053] The metal peroxide complex molecular catalyst synthesis solution prepared above is not separated. A catalyst system containing 0.01 mol of the metal peroxide complex is mixed with a reaction system containing 0.2 mol of a thioether intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) to obtain a mixed material. The mixed material and a hydrogen peroxide solution (oxidant) are introduced into a continuous coil reactor for oxidation reaction to obtain a sulfonepyrazoline reaction solution. The hydrogen peroxide solution has a mass concentration of 50% and is introduced at a flow rate of 0.2 g / min. The mixed material is introduced at a flow rate of 6.0 g / min. The molar ratio of the oxidant to the thioether intermediate is 2:1. The oxidation reaction temperature is 55°C and the reaction time is 60 minutes.

[0054] The sulfentrazone reaction solution was tested for relevant properties by liquid chromatography, and the results are shown in Table 1.

[0055] Example 3

[0056] (1) Preparation of metal peroxo complex molecular catalyst

[0057] 0.01 mol of rhenium chloride (ReCl3) was dissolved in 1 L of a mixed solution of deionized water and acetonitrile (V 水 :V 乙腈 =1:1) and stirred at 30°C for 1 h to prepare a rhenium chloride solution with a transition metal ion concentration of 0.01 mol / L. 0.03 mol of ethylenediamine organic ligand was dissolved in the above rhenium chloride solution and stirred and mixed at the temperature for 0.5 h to obtain a mixed solution; after adjusting the pH of the mixed solution to 6 with 0.1 mol / L hydrochloric acid, the obtained solution was stirred and reacted at 30°C for 10 h to obtain a second solution containing a metal organic complex. The obtained second solution was cooled to 10°C, and 0.05 mol of a 30% mass fraction hydrogen peroxide solution was slowly added thereto and continuously stirred for 2 h to obtain a metal peroxo complex molecular catalyst.

[0058] (2) Synthesis of sulfentrazone

[0059] The metal peroxo complex molecular catalyst obtained by the above preparation does not need to be separated, and a reaction system containing 0.01 mol of the metal peroxo complex and containing 0.2 mol of a sulfide intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) was mixed to obtain a mixed material; the mixed material and a hydrogen peroxide solution (oxidizing agent) were introduced into a continuous coil reactor for oxidation reaction to obtain a sulfentrazone reaction solution. The mass concentration of the hydrogen peroxide solution was 50%, and the flow rate of the introduction was 0.2 g / min; the flow rate of the introduction of the mixed material was 6.0 g / min; the molar ratio of the oxidizing agent to the sulfide intermediate was 3:1. The oxidation reaction temperature was 45°C, and the time was 120 min.

[0060] The sulfentrazone reaction solution was tested for relevant properties by liquid chromatography, and the results are shown in Table 1.

[0061] Example 4

[0062] (1) Preparation of metal peroxo complex molecular catalyst

[0063] 0.01 mol of ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O 24 ·4H2O) and 0.03 mol of zinc chloride (ZnCl2) were dissolved in 1 L of a mixed solution of deionized water and acetonitrile (V水 :V 乙腈 =1:1), stirred at 50°C for 1 h, and prepared into a mixed solution with a transition metal ion concentration of 0.1 mol / L. 0.2 mol of citric acid organic ligand was dissolved in the above mixed solution, and the mixture was stirred at the temperature for 0.5 h to obtain a mixed solution; after adjusting the pH of the mixed solution to 4 with isopropylamine, the obtained solution was stirred at 40°C for 8 h to obtain a second solution containing a metal organic complex. After cooling the obtained second solution to 20°C, 1 mol of a 30% mass fraction hydrogen peroxide solution was slowly added thereto and stirred for 2 h to obtain a metal peroxo complex molecular catalyst.

[0064] (2) Synthesis of Metamifop

[0065] The metal peroxo complex molecular catalyst synthesis solution prepared above does not need to be separated, and a catalytic system containing 0.01 mol of the metal peroxo complex and a reaction system containing 0.2 mol of a sulfide intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) are mixed to obtain a mixed material; the mixed material and a hydrogen peroxide solution (oxidizing agent) are introduced into a continuous coil reactor to perform an oxidation reaction to obtain a metamifop reaction solution. The mass concentration of the hydrogen peroxide solution is 50%, and the flow rate of the introduction is 0.2 g / min; the flow rate of the introduction of the mixed material is 6.0 g / min; and the molar ratio of the oxidizing agent to the sulfide intermediate is 4:1. The oxidation reaction is performed at a temperature of 50°C for 120 min.

[0066] The metamifop reaction solution obtained is tested for relevant performance by liquid chromatography, and the results are shown in Table 1.

[0067] Example 5

[0068] (1) Preparation of a metal peroxo complex molecular catalyst

[0069] 0.02 mol of sodium molybdate (Na2MoO4) and 0.03 mol of cerium trichloride (CeCl3) were dissolved in 1 L of deionized water, stirred at 40°C for 0.5 h, and prepared into a mixed solution with a transition metal ion concentration of 0.05 mol / L. 0.1 mol of bipyridine organic ligand was dissolved in the above mixed solution, and the mixture was stirred at the temperature for 0.5 h to obtain a mixed solution; after adjusting the pH of the mixed solution to 4 with a 0.1 mol / L hydrochloric acid aqueous solution, the obtained solution was stirred at 50°C for 6 h to obtain a second solution containing a metal organic complex. After cooling the obtained second solution to 15°C, 0.1 mol of a 1 mol / L sodium persulfate solution was slowly added thereto and stirred for 3 h to obtain a metal peroxo complex molecular catalyst.

[0070] (2) Synthesis of metrafenone

[0071] The metal peroxide complex molecular catalyst synthesis solution obtained by the above preparation does not need to be separated. A reaction system containing 0.01 mol of the metal peroxide complex and 0.2 mol of a sulfide intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) is mixed to obtain a mixture. The mixture and a hydrogen peroxide solution (oxidizing agent) are introduced into a continuous coil reactor to perform an oxidation reaction, and a metrafenone reaction solution is obtained. The mass concentration of the hydrogen peroxide solution is 50%, and the flow rate of the introduction is 0.2 g / min. The flow rate of the introduction of the mixture is 6.0 g / min. The molar ratio of the oxidizing agent to the sulfide intermediate is 2:1. The temperature of the oxidation reaction is 50°C, and the time is 90 min.

[0072] The metrafenone reaction solution obtained is tested for related properties by liquid chromatography, and the results are shown in Table 1.

[0073] Example 6

[0074] (1) Preparation of metal peroxide complex molecular catalyst

[0075] 0.01 mol of titanium sulfate (TiOSO4), 0.01 mol of sodium metavanadate (NaVO3), and 0.01 mol of ammonium molybdate ((NH4)2MoO4) are dissolved in 1 L of deionized water, stirred at 50°C for 1 h, and prepared into a mixed solution with a transition metal ion concentration of 0.03 mol / L. 0.06 mol of an organic ligand of tartaric acid is dissolved in the mixed solution, and the mixture is stirred at the temperature for 0.5 h to obtain a mixed solution. After adjusting the pH of the mixed solution to 2 with 0.1 mol / L hydrochloric acid, the obtained solution is stirred and reacted at 70°C for 2 h to obtain a second solution containing a metal organic complex. After the second solution is cooled to 25°C, 0.06 mol of a sodium persulfate solution with a concentration of 0.1 mol / L is slowly added thereto and continuously stirred for 4 h to obtain a metal peroxide complex molecular catalyst.

[0076] (2) Synthesis of metrafenone

[0077] The metal peroxide complex molecular catalyst synthesis solution prepared above was mixed without separation. A catalyst system containing 0.01 mol of the metal peroxide complex was mixed with a reaction system containing 0.2 mol of a thioether intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) to obtain a mixed material. The mixed material and a hydrogen peroxide solution (oxidant) were introduced into a continuous coil reactor for oxidation to produce a sulfonepyrazoline reaction solution. The hydrogen peroxide solution had a mass concentration of 50% and was introduced at a flow rate of 0.2 g / min. The mixed material was introduced at a flow rate of 6.0 g / min. The molar ratio of the oxidant to the thioether intermediate was 4:1. The oxidation reaction temperature was 55°C and the reaction time was 120 minutes.

[0078] The obtained sulfonepyraclostrobin reaction solution was tested for relevant properties by liquid chromatography, and the results are shown in Table 1.

[0079] Example 7

[0080] (1) Preparation of metal peroxide complex molecular catalysts

[0081] 0.01 mol titanium sulfate (Ti(SO4)2), 0.01 mol sodium metavanadate (NaVO3), 0.005 mol phosphomolybdic acid (H3[P(Mo3O 10 )4]) and 0.01 mol zinc nitrate (Zn(NO3)2) were dissolved in 1 L of deionized water and stirred at 60°C for 0.5 h to prepare a mixed solution with a transition metal ion concentration of 0.09 mol / L. 0.09 mol of malic acid organic ligand was dissolved in the mixed solution and stirred at the same temperature for 0.5 h to obtain a mixed solution. After adjusting the pH of the mixed solution to 4 with tripropylamine, the resulting solution was stirred at 60°C for 4 h to obtain a second solution containing the metal organic complex. After cooling the resulting second solution to 25°C, 0.18 mol of ozone was slowly added and stirred for 4 h to obtain the metal peroxide complex molecular catalyst.

[0082] (2) Synthesis of sulfonepyraclostrobin

[0083] The prepared metal peroxo complex molecular catalyst synthesis solution is mixed with a reaction system containing 0.01 mol of metal peroxo complex and 0.2 mol of thioether intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4, 5-dihydro-5, 5-dimethyl-1, 2-isoxazole) to obtain a mixture; the mixture is introduced into a continuous coil reactor with hydrogen peroxide solution (oxidant) to perform an oxidation reaction, to obtain a mesotrione reaction solution. The mass concentration of the hydrogen peroxide solution is 50%, and the flow rate of the introduction is 0.2 g / min; the flow rate of the introduction of the mixture is 6.0 g / min; the molar ratio of the oxidant to the thioether intermediate is 2:1. The temperature of the oxidation reaction is 55°C, and the time is 120 min.

[0084] The obtained mesotrione reaction solution is tested for relevant performance by liquid chromatography, and the results are shown in Table 1.

[0085] Example 8

[0086] (1) Preparation of metal peroxo complex molecular catalyst

[0087] 0.01 mol of titanium sulfate (Ti(SO4)2), 0.01 mol of vanadyl trichloride (VOCl3), 0.005 mol of ammonium molybdophosphate ((NH4)3PMo 12 O 40 ), 0.01 mol of zinc sulfate (ZnSO4), and 0.01 mol of cerium nitrate (Ce(NO3)3) are dissolved in 1 L of deionized water, stirred at 40°C for 1 h, to prepare a mixed solution with a transition metal ion concentration of 0.1 mol / L. 0.3 mol of imidazole organic ligand is dissolved in the mixed solution, and the mixture is stirred at the temperature for 0.5 h to obtain a mixed solution; after adjusting the pH of the mixed solution to 3 with 1 mol / L nitric acid aqueous solution, the obtained solution is stirred at 50°C for 8 h to obtain a second solution containing a metal organic complex. The obtained second solution is cooled to 5°C, and 0.5 mol of ammonium persulfate solution with a concentration of 0.5 mol / L is slowly added thereto and continuously stirred for 4 h to obtain a metal peroxo complex molecular catalyst.

[0088] (2) Synthesis of mesotrione

[0089] The prepared metal peroxide complex molecular catalyst synthesis solution is mixed with a reaction system containing 0.01 mol of metal peroxide complex and 0.2 mol of thioether intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4, 5-dihydro-5, 5-dimethyl-1, 2-isoxazole) to obtain a mixture; the mixture is introduced into a continuous coil reactor with hydrogen peroxide solution (oxidizing agent) to perform an oxidation reaction, to obtain a mesotrione reaction solution. The mass concentration of the hydrogen peroxide solution is 50%, and the flow rate of the introduction is 0.2 g / min; the flow rate of the introduction of the mixture is 6.0 g / min; the molar ratio of the oxidizing agent to the thioether intermediate is 2:1. The oxidation reaction is performed at a temperature of 50°C for 60 min.

[0090] The obtained mesotrione reaction solution is tested for relevant performance by liquid chromatography, and the results are shown in Table 1.

[0091] Example 9

[0092] (1) Preparation of metal peroxide complex molecular catalyst

[0093] 0.01 mol of titanium potassium oxalate (K2TiO(C2O4)2·2H2O), 0.01 mol of ammonium metavanadate (NH4VO3), 0.02 mol of molybdenum chloride (MoCl5), 0.02 mol of rhenium chloride (ReCl3), 0.02 mol of zinc chloride (ZnCl2), and 0.01 mol of cerium sulfate (Ce2(SO4)3) are dissolved in 1 L of deionized water, stirred at 30°C for 1 h, and prepared into a mixed solution with a transition metal ion concentration of 0.1 mol / L. 0.1 mol of ethylenediaminetetraacetic acid organic ligand is dissolved in the above-mentioned mixed solution, and the mixture is stirred at the temperature for 0.5 h to obtain a mixed solution; after adjusting the pH of the mixed solution to 5 with butylamine, the obtained solution is stirred at 80°C for 6 h to obtain a second solution containing a metal organic complex. After cooling the obtained second solution to 25°C, 0.2 mol of 10% hydrogen peroxide solution is slowly added to the solution and continuously stirred for 4 h to obtain a metal peroxide complex molecular catalyst.

[0094] (2) Synthesis of mesotrione

[0095] The prepared metal peroxide complex molecular catalyst synthesis solution is mixed with a reaction system containing 0.01 mol of metal peroxide complex and 0.2 mol of sulfide intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) without separation to obtain a mixture; the mixture is introduced into a continuous coil reactor with hydrogen peroxide solution (oxidizing agent) to perform an oxidation reaction to obtain a reaction solution of pyroxasulfuron-ethyl. The mass concentration of the hydrogen peroxide solution is 50%, and the flow rate of the introduction is 0.2 g / min; the flow rate of the introduction of the mixture is 6.0 g / min; and the molar ratio of the oxidizing agent to the sulfide intermediate is 4:1. The temperature of the oxidation reaction is 50°C, and the time is 120 min.

[0096] The obtained reaction solution of pyroxasulfuron-ethyl is tested for related properties by liquid chromatography, and the results are shown in Table 1.

[0097] Example 10

[0098] The difference between Example 10 and Example 1 is that a kettle reactor is used to synthesize pyroxasulfuron-ethyl, and the catalyst used is prepared in Example 1.

[0099] At 25°C, a reaction kettle is added with a reaction system containing 0.01 mol of metal peroxide complex, 0.2 mol of sulfide intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole), and 1.0 mol of hydrogen peroxide solution with a mass concentration of 50%, and the mixture is stirred and mixed uniformly to obtain a mixture; then the reaction kettle is heated to 60°C and kept at this temperature for 30 min to perform an oxidation reaction, and after the reaction is completed, the reaction kettle is placed in an ice water bath for rapid cooling to terminate the reaction.

[0100] The obtained reaction solution of pyroxasulfuron-ethyl is tested for related properties by liquid chromatography, and the results are shown in Table 1.

[0101] Example 11

[0102] (1) Preparation of metal peroxide complex molecular catalyst

[0103] Potassium titanium oxalate (K2[TiO(C2O4)2]·2H2O) 0.12 mol was dissolved in 1 L of deionized water, stirred at 30 °C for 1 h to prepare a potassium titanium oxalate solution with a transition metal ion concentration of 0.12 mol / L. Glycine organic ligand 0.36 mol was dissolved in the potassium titanium oxalate solution and stirred at the temperature for 0.5 h to obtain a mixed solution; after adjusting the pH of the mixed solution to 6.5 with triethylamine, the obtained solution was stirred at 60 °C for 5 h to obtain a second solution containing a metal organic complex. After cooling the obtained second solution to 25 °C, 0.24 mol of 6% mass fraction hydrogen peroxide aqueous solution was slowly added thereto and stirred for 4 h to obtain a metal peroxo complex molecular catalyst.

[0104] (2) Synthesis of Metrafenone

[0105] The metal peroxo complex molecular catalyst synthesis solution prepared above does not need to be separated, and a catalytic system containing 0.01 mol of the metal peroxo complex is mixed with a reaction system containing 0.2 mol of a sulfide intermediate (3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole) to obtain a mixed material; the mixed material and a hydrogen peroxide solution are introduced into a continuous coil reactor for oxidation reaction to obtain a metrafenone reaction solution. The mass concentration of the hydrogen peroxide solution is 50%, and the flow rate of the introduction is 0.2 g / min; the flow rate of the introduction of the mixed material is 6.0 g / min; the molar ratio of the oxidant to the sulfide intermediate is 5:1. The oxidation reaction temperature is 60 °C, and the time is 30 min.

[0106] The obtained metrafenone reaction solution is tested for related performance by liquid chromatography, and the results are shown in Table 1.

[0107] Comparative Example 1

[0108] The difference between Comparative Example 1 and Example 1 is that sodium tungstate is used as the catalyst.

[0109] Comparative Example 2

[0110] The difference between Comparative Example 2 and Example 10 is that sodium tungstate is used as the catalyst.

[0111] Comparative Example 3

[0112] Comparative Example 3 uses the metal organic complex in the second solution containing a metal organic complex prepared in Example 1 as a catalyst, and the second solution containing a metal organic complex does not need to be separated and is used directly.

[0113] The metal peroxide complex molecule catalyst prepared by the above examples and comparative examples was used for synthesizing furilazole, and the obtained reaction liquid was tested for relevant performance, and the conversion rate of raw materials and the selectivity of furilazole were calculated, and the results are shown in Table 1.

[0114] Table 1

[0115] Item Oxidation reaction temperature (°C) Oxidation reaction time (min) Conversion rate (%) Selectivity (%) Example 1 60 30 100 96.5 Example 2 55 60 100 96.0 Example 3 45 120 100 97.1 Example 4 50 120 100 98.0 Example 5 50 90 100 96.7 Example 6 55 120 100 97.5 Example 7 55 120 100 96.1 Example 8 50 60 100 96.9 Example 9 50 120 100 97.8 Example 10 60 30 100 95.8 Example 11 60 30 100 95.2 Comparative Example 1 60 30 100 91.0 Comparative Example 2 60 30 100 90.6 Comparative Example 3 60 30 100 83.4

[0116] From the above description, it can be seen that the above-mentioned examples of the present application achieve the following technical effects:

[0117] In examples 1 to 11, the metal peroxide complex molecule catalyst prepared by the preparation method provided by the present application is used to participate in the process of synthesizing furilazole from 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole. According to the results in Table 1, the above preparation and synthesis process has good conversion rate and selectivity, especially when the parameters in the catalyst preparation process are controlled within the preferred range, the selectivity of the corresponding examples is better.

[0118] In comparative examples 1 and 2, sodium tungstate is used as a catalyst to participate in the reaction of synthesizing furilazole from 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole. The selectivity of the product furilazole in the above two comparative examples has a large gap compared with the examples of the present application. In comparative example 3, the metal organic complex prepared in example 1 is used as a catalyst to participate in the synthesis of furilazole, and the results in the table show that the selectivity of the product is also greatly different compared with the examples of the present application.

[0119] In summary, the metal peroxide complex molecule catalyst prepared by the preparation method provided by the present application has excellent selectivity and catalytic efficiency as a catalyst for oxidizing sulfide to sulfone under the synergistic effect of the transition metal ion center, organic ligand and metal-peroxide bridge (M-O-O-M) structure. When it is used for synthesizing furilazole, it can effectively improve the reaction efficiency, selectivity and safety of the oxidation reaction, thereby facilitating further reduction of the preparation cost of furilazole.

[0120] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the preparation of a metal peroxo complex molecular catalyst for catalyzing the synthesis of the sulfonyl form of pyroxasulfone, 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole, characterized in that, The preparation method comprises the following steps: The soluble metal salt is first mixed with a solvent to obtain a first solution; wherein the metal ion in the soluble metal salt is a transition metal ion; The organic ligand is secondly mixed with the first solution to obtain a mixed solution; the mixed solution is heated to perform a first reaction to obtain a second solution containing a metal organic complex; A first oxidant is added to the second solution to perform a second reaction to generate the metal peroxo complex molecular catalyst; The first oxidant is used to provide at least one of superoxide anion, peroxide bond, hydroxyl radical, singlet oxygen or ozone to make the metal organic complex generate the metal peroxo complex molecular catalyst containing a metal peroxo bridge bond; the temperature of the first reaction is 30-80℃, and the time is 1-10h; The transition metal ion is selected from at least one of titanium ion, vanadium ion, molybdenum ion, rhenium ion, zinc ion and cerium ion; Before the first reaction is performed, the preparation method further comprises: adjusting the pH value of the mixed solution; the pH value of the mixed solution is adjusted to 2-6; The temperature of the second reaction is 5-25℃, and the time is 1-4h; The molar ratio of the first oxidant to the metal organic complex is (2-15):

1.

2. The method for preparing the metal peroxide complex molecular catalyst according to claim 1, characterized in that: The organic ligand contains one or more of oxygen atom, nitrogen atom, hydroxyl and carboxyl; And / or, the soluble metal salt is selected from one or more of titanium sulfate, titanyl sulfate, potassium titanium oxalate, ammonium metavanadate, sodium metavanadate, vanadyl trichloride, ammonium molybdate, ammonium heptamolybdate tetrahydrate, sodium molybdate, potassium molybdate, molybdenum chloride, phosphomolybdic acid, ammonium phosphomolybdate, rhenium chloride, zinc nitrate, zinc chloride, zinc sulfate, cerium nitrate, cerium chloride and cerium sulfate.

3. The method for preparing the metal peroxide complex molecular catalyst according to claim 2, characterized in that: The organic ligand is selected from one or more of glycine, triethanolamine, ethylenediamine, porphyrin, bipyridine, imidazole, oxalic acid, citric acid, tartaric acid, malic acid and ethylenediaminetetraacetic acid.

4. The method for preparing the metal peroxide complex molecular catalyst according to claim 1, characterized in that: The first oxidant is at least one of ozone, hydrogen peroxide and persulfate.

5. The method of preparing a metal superoxide complex molecular catalyst according to any one of claims 1 to 4, characterized by, The solvent used for adjusting the pH value is at least one of inorganic acid aqueous solution or organic base; And / or, the organic base is selected from one or more of triethylamine, propylamine, isopropylamine, 1,3-propanediamine, 1,2-propanediamine, tripropylamine, butylamine, isobutylamine and tert-butylamine; And / or, the molar ratio of the metal ion to the organic ligand is 1:(1-3); And / or, the temperature of the second mixing is 30-60℃, and the time is 0.5-1h.

6. The method of claim 5, wherein the metalloperoxo complex molecular catalyst is prepared by the process comprising: (a) contacting a metal complex with a peroxide compound in a solvent to form a mixture; and (b) isolating the metalloperoxo complex molecular catalyst from the mixture. The inorganic acid aqueous solution is hydrochloric acid aqueous solution and / or nitric acid aqueous solution.

7. The method for preparing the metal peroxide complex molecular catalyst according to claim 6, characterized in that: The concentration of the inorganic acid aqueous solution is 0.1-12mol / L.

8. The method of preparing a metal superoxide complex molecular catalyst according to any one of claims 1 to 4, characterized by, The solvent is water, or a mixture of water and acetonitrile.

9. The method of preparing a metal superoxide complex molecular catalyst according to any one of claims 1 to 4, characterized by, The concentration of the transition metal ion in the first solution is 0.01-0.1mol / L; And / or, the temperature of the first mixing is 30-60℃, and the time is 0.5-1h.

10. A metal peroxo complex molecular catalyst for catalyzing the preparation of synthetic tolfenpyrad from 3-[(5-difluoromethoxy-l-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-l,2-isoxazole, characterized in that, The metal peroxo complex molecular catalyst is prepared by the preparation method in any one of claims 1 to 9.

11. A continuous process for the synthesis of metalachlor, characterized in that, The synthesis method comprises the following steps: Mixing 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole with the metal peroxo complex molecular catalyst of claim 10 to obtain a mixture; Continuously feeding the mixture and a second oxidant into a coil reactor to perform an oxidation reaction to obtain the metal peroxo complex molecular catalyst.

12. The continuous synthesis of metalachlor according to claim 11, characterized in that, The molar ratio of the metal peroxo complex molecular catalyst to the 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole is (0.05-0.1):1; And / or, the molar ratio of the second oxidant to the 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio]-4,5-dihydro-5,5-dimethyl-1,2-isoxazole is (2-5):

1.

13. The continuous synthesis of metalachlor according to claim 11 or 12, characterized in that, The temperature of the oxidation reaction is 45-60°C, and the time is 30-120 min; And / or, the second oxidant is hydrogen peroxide.