Method for synthesizing pyroxasulfone

Abstract

The application relates to the technical field of organic synthesis, and discloses a method for synthesizing metrafenone. The method comprises the following steps: feeding a solution of a compound of formula II and a first oxidant into a micro-channel reactor to perform a first reaction, so as to obtain a solution containing a compound of formula III; feeding the solution containing the compound of formula III and a second oxidant into a tubular reactor to perform a second reaction, so as to obtain a compound of formula I. The micro-channel reactor and the tubular reactor which can realize intensified mixing are connected in series to realize continuous flow reaction, the compound of formula II is oxidized into the compound of formula I, and the speed, yield, purity and safety of the oxidation reaction are improved.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and specifically to a method for synthesizing sulfonylpyrazine. Background Technology

[0002] Sulfonazole is a pre-emergence soil-applied herbicide developed by Japanese Combinatorial Chemicals and Anbara Chemicals Co., Ltd., applicable to most crop fields. Its mechanism of action involves absorption by the young roots and shoots of weeds, disrupting the seedling meristem and coleoptile. It is a potential inhibitor of VLCFA (very long-chain fatty acid) biosynthesis in plants, thus inhibiting early seedling growth. Sulfonazole has attracted widespread attention due to its broad-spectrum, high-efficiency, and environmentally friendly characteristics.

[0003] Currently, all publicly disclosed preparation methods require the oxidation of thioether intermediates to obtain the target product, sulfopyrazol. The m-chloroperoxybenzoic acid (m-CPBA) disclosed in WO2004 / 013106A1 is relatively expensive for industrial applications and presents problems in terms of treatment and waste disposal.

[0004] In addition, in the method for preparing sulfonylpyrazine (compound I) from a thioether intermediate (compound II), the reaction process of oxidizing to generate the intermediate sulfoxide derivative (SO derivative, compound III) is highly exothermic and violent, and this compound may stop the reaction.

[0005]

[0006] CN111393427A improved the preparation method by using sodium tungstate as a catalyst and directly oxidizing sulfide to sulfone with hydrogen peroxide. However, the above method has a long reaction time (8-10 hours), resulting in a long production cycle and complicated post-processing operations, which is not conducive to industrial production.

[0007] CN118255757A uses a microchannel reactor for the final oxidation step, also employing sodium tungstate as a catalyst and hydrogen peroxide as an oxidant. However, this method is not only cumbersome in post-processing, but also offers no advantage in reaction time and yields a low product yield.

[0008] Therefore, there is an urgent need to develop a method for synthesizing sulfopyrazole that has a short reaction time, high yield and purity, and good safety. Summary of the Invention

[0009] The purpose of this invention is to overcome the problems existing in the prior art and provide a method for synthesizing sulfonylpyrazole.

[0010] To achieve the above objectives, the present invention provides a method for synthesizing sulfonylpyrazole, wherein the method includes the following steps:

[0011] (1) The feed solution of compound II and the first oxidant are introduced into a microchannel reactor to carry out the first reaction, and a feed solution containing compound III is obtained;

[0012]

[0013] (2) The feed liquid containing the compound of formula III and the second oxidant are introduced into a tubular reactor to carry out the second reaction to obtain the compound of formula I;

[0014]

[0015] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0016] (1) The present invention achieves continuous flow reaction by connecting a microchannel reactor and a tubular reactor that can achieve enhanced mixing, thereby oxidizing compound II into compound I, which improves the speed, yield, purity and safety of the oxidation reaction.

[0017] (2) The present invention provides a synthesis method that greatly improves the safety of the production process, shortens the reaction time, improves the production efficiency, and has small equipment size and small footprint, thus having good economic benefits and application value. Attached Figure Description

[0018] Figure 1 This is a flowchart of the synthesis of sulfonylpyrazine in Example 1 of the present invention;

[0019] Figure 2 This is the liquid phase tracking spectrum of the reaction in Example 13 of this invention;

[0020] Figure 3 This is the liquid phase tracking spectrum of the reaction in Example 14 of this invention;

[0021] Figure 4 This is the liquid phase tracking spectrum of the reaction in Example 20 of the present invention. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] This invention provides a method for synthesizing sulfonylpyrazole, wherein the method includes the following steps:

[0024] (1) The feed solution of compound II and the first oxidant are introduced into a microchannel reactor to carry out the first reaction, and a feed solution containing compound III is obtained;

[0025]

[0026] (2) The feed liquid containing the compound of formula III and the second oxidant are introduced into a tubular reactor to carry out the second reaction to obtain the compound of formula I;

[0027]

[0028] In this invention, the corresponding feed liquid and oxidant in steps (1) and (2) can be simultaneously introduced into the microchannel reactor or tubular reactor via metering pumps.

[0029] Based on the reaction characteristics of synthesizing compound I from compound II, this invention first oxidizes compound II to compound III in a microchannel reactor, and then further oxidizes compound III to compound I in a tubular reactor. Thus, the compound II, as a raw material, is completely oxidized to compound I (i.e., sulfonylpyrazine) through two steps in different reactors.

[0030] This invention significantly shortens the overall oxidation reaction time through the above-described scheme, and further improves the yield and purity of the final product, sulfonylpyrazine. Using a microchannel reactor to convert sulfoether compounds into sulfoxide compounds allows for rapid heat transfer and dissipation, effectively preventing localized overheating, reducing side reactions, and preventing runaway temperatures due to heat accumulation, thus improving safety. Using a tubular reactor ensures complete conversion of sulfoxide compounds into sulfone compounds, and also increases the oxidation reaction rate and conversion efficiency.

[0031] The reactions that occur in this invention are as follows:

[0032]

[0033] In some embodiments of the present invention, in step (1), the liquid of the formula II compound includes the formula II compound and an organic solvent.

[0034] In some embodiments of the present invention, the organic solvent is selected from at least one of methanol, ethanol, acetonitrile, tetrahydrofuran, N,N-dimethylformamide and N,N-dimethylacetamide, preferably methanol or acetonitrile, and more preferably methanol.

[0035] In some embodiments of the present invention, in step (1), the first oxidant is hydrogen peroxide.

[0036] In some embodiments of the present invention, the molar ratio of the compound of formula II to the first oxidant is 1:1-1.2, preferably 1:1.05. In the present invention, the amount of the first oxidant is insufficient for complete oxidation to a sulfone compound, and oxidation continues through a subsequent reaction. Therefore, quenching is not required in the microchannel reactor, saving process steps.

[0037] In some embodiments of the present invention, the temperature of the first reaction is 0-100°C, preferably 25-30°C.

[0038] In some embodiments of the present invention, the time of the first reaction is 3-20s, preferably 3-7s, and more preferably 5s.

[0039] In some embodiments of the present invention, in step (2), the tubular reactor is loaded with a metal-based solid catalyst.

[0040] This invention innovatively uses a metal-based solid catalyst in the synthesis of sulfopyrazine, and achieves higher reaction activity through screening of active ingredients and supports.

[0041] In some embodiments of the present invention, the active component of the metal-based solid catalyst is selected from at least one of Ru, Ag and Cu, preferably Ru and Cu.

[0042] In some embodiments of the present invention, the support for the metal-based solid catalyst is selected from molecular sieves and / or activated alumina, preferably molecular sieves, and more preferably HZSM-5 molecular sieves.

[0043] In some embodiments of the present invention, the preparation method of the metal-based solid catalyst includes: impregnating a support in a soluble metal salt solution, and drying and calcining the support after impregnation to obtain the metal-based solid catalyst.

[0044] In some embodiments of the present invention, the metal salt in the soluble metal salt solution is selected from at least one of ruthenium chloride, ruthenium acetate, ruthenium nitrate, silver nitrate, copper chloride, and copper nitrate, preferably ruthenium acetate and copper nitrate.

[0045] In some embodiments of the present invention, the impregnation conditions include: a temperature of 30-60°C, preferably 40°C; and a time of 12-30 hours, preferably 16 hours.

[0046] In some embodiments of the present invention, the drying conditions include: a temperature of 90-120°C, preferably 110°C; and a time of 5-8 hours, preferably 6 hours.

[0047] In some embodiments of the present invention, the roasting conditions include: a temperature of 200-500℃, preferably 250-300℃; and a time of 2-5 hours, preferably 4 hours. In the present invention, the roasting time refers to the holding time at a specific roasting temperature.

[0048] In some embodiments of the present invention, in step (2), the second oxidant is air and / or oxygen. Air and oxygen are less expensive and easier to handle than hydrogen peroxide.

[0049] In some embodiments of the present invention, the molar ratio of the compound of formula III to the second oxidant is 1:1-2, preferably 1:1.1. When air is used as the second oxidant, its molar amount is expressed as the amount of oxygen it contains.

[0050] In some embodiments of the present invention, in step (2), the temperature of the second reaction is 30-90°C, preferably 50-55°C.

[0051] In some embodiments of the present invention, the pressure of the second reaction is 0.5-3 MPa, preferably 1 MPa.

[0052] In some embodiments of the present invention, the second reaction time is 2-5 minutes, preferably 3 minutes.

[0053] In some embodiments of the present invention, in step (2), the product of the second reaction is subjected to gas-liquid separation, and water is added to the obtained liquid material for stirring, filtration, and drying to obtain compound I.

[0054] In this invention, a gas-liquid separator can be used for gas-liquid separation, and then the liquid material is introduced into a batch reactor and stirred with water.

[0055] The present invention will be described in detail below through embodiments.

[0056] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0057] Ruthenium acetate has the molecular formula C2H4O2Ru, CAS number 72196-32-8, and molecular weight 161.12.

[0058] The preparation method of the metal-based solid catalyst used in the following examples is as follows:

[0059] Preparation of metal-based solid catalyst Ru-Cu / HZSM-5:

[0060] (1) Weigh out 55.64g of ruthenium acetate (0.345mol) and 18.76g of copper nitrate (0.148mol) respectively and dissolve them in 1L of water. Stir to completely dissolve the salts.

[0061] (2) Add 200g of HZSM-5 molecular sieve to the above solution and impregnate at 40℃ for 16h; dry at 110℃ for 6h and then place in a muffle furnace and calcine at 300℃ for 4h (heating up for 1.5h and holding for 4h) to obtain Ru-Cu / HZSM-5 catalyst.

[0062] Preparation of metal-based solid catalyst Ru / HZSM-5:

[0063] (1) Weigh 83.46g of ruthenium acetate (0.518mol) and dissolve it in 1L of water, stirring until the salt is completely dissolved;

[0064] (2) Add 200g of HZSM-5 molecular sieve to the above solution and impregnate at 40℃ for 16h; dry at 110℃ for 6h and then place in a muffle furnace and calcine at 300℃ for 4h (heating up for 1.5h and holding for 4h) to obtain Ru / HZSM-5 catalyst.

[0065] Preparation of the metal-based solid catalyst Cu / HZSM-5:

[0066] (1) Weigh 75.04g of copper nitrate (0.593mol) and dissolve it in 1L of water, stirring until the salt is completely dissolved;

[0067] (2) Add 200g of HZSM-5 molecular sieve to the above solution and impregnate it at 40℃ for 16h; dry it at 110℃ for 6h and then place it in a muffle furnace and calcine it at 250℃ for 4h (heating up for 1h and holding for 4h) to obtain Cu / HZSM-5 catalyst.

[0068] Preparation of metal-based solid catalyst Ag / HZSM-5

[0069] (1) Weigh 67.95g of silver nitrate (0.400mol) and dissolve it in 1L of water, stirring until the salt is completely dissolved;

[0070] (2) Add 200g of HZSM-5 molecular sieve to the above solution and soak at 40℃ for 16h; dry at 110℃ for 6h and then place in a muffle furnace to calcine at 250℃ for 4h (heating up for 1h and holding for 4h).

[0071] Preparation of metal-based solid catalyst Ru-Cu / Al2O3:

[0072] (1) Weigh out 55.64g of ruthenium acetate (0.345mol) and 18.76g of copper nitrate (0.148mol) respectively and dissolve them in 1L of water. Stir to completely dissolve the salts.

[0073] (2) Add 200g of active alumina to the above solution and impregnate at 40℃ for 16h; dry at 110℃ for 6h and then place in a muffle furnace to calcine at 300℃ for 4h (heating up for 1.5h and holding for 4h) to obtain Ru-Cu / Al2O3 catalyst.

[0074] The catalyst described above is loaded into a tubular reactor for use.

[0075] The content of various compounds is determined by liquid chromatography (LC).

[0076] Example 1

[0077] This example illustrates the synthesis of sulfonylpyrazine, such as... Figure 1 As shown.

[0078] 1) Material preparation: At room temperature, dissolve compound II (359.3 g, 1 mol, 1 eq) in 1.5 L of methanol and temporarily store it in a storage tank; place hydrogen peroxide solution (80.1 g, 27.5%, 1.05 mol, 1.05 eq) in another storage tank;

[0079] 2) Preheat the microchannel reactor to 30°C, then inject the methanol solution of compound II and the hydrogen peroxide solution into the microchannel reactor at a molar ratio of 1:1.05 using metering pumps to mix and react. The reaction residence time is 5s. Samples of the material flowing out of the channel outlet are taken for testing. If the raw material is completely converted, the material is collected into the liquid tank.

[0080] 3) Set the temperature of the tubular reactor (filled with Ru-Cu / HZSM-5 catalyst) to 55℃, connect the metering pump to the feed tank, and connect the gas flow meter to the air cylinder. Set the flow rate so that the molar ratio of Formula III compound to oxygen in the air is 1:1.1. First, open the gas phase valve to release air and control the system pressure to 1MPa. Then, start the pump to pump the material into the tubular reactor for reaction. The residence time in the tubular reactor is about 3 minutes.

[0081] 4) The reaction liquid flowing out of the tubular reactor is separated by a gas-liquid separator, and the liquid phase is sampled and tested. The reaction of compound III is complete; the liquid material is collected into a liquid treatment tank.

[0082] 5) Add 1.5L of water to the liquid treatment tank, stir thoroughly, filter, and dry to obtain 381.5g of white solid sulfonylpyrazol (compound I), with a yield of 96.8% and a purity of 99.3%.

[0083] Example 2-11

[0084] Sulfonazole was synthesized according to the method in Example 1, except that the catalyst in the tubular reactor was reused for 10 batches, and the test data are shown in Table 1.

[0085] Table 1

[0086] serial number Apply batch Yield (%) content(%) Example 2 1 96.6 99.3 Example 3 2 96.6 99.1 Example 4 3 96.7 99.2 Example 5 4 96.5 99.3 Example 6 5 96.8 99.1 Example 7 6 96.6 99.3 Example 8 7 96.7 99.3 Example 9 8 96.8 99.2 Example 10 9 96.5 99.1 Example 11 10 96.6 99.3

[0087] As can be seen from Table 1, the yield and content of the catalyst were stable after 10 batches were reused in the tubular reactor, with basically no impact.

[0088] Example 12

[0089] This example illustrates the synthesis of sulfonylpyrazine.

[0090] 1) Material preparation: At room temperature, dissolve compound II (359.3 g, 1 mol, 1 eq) in 1.5 L of methanol and temporarily store it in a storage tank; place hydrogen peroxide solution (80.1 g, 27.5%, 1.05 mol, 1.05 eq) in another storage tank;

[0091] 2) Preheat the microchannel reactor to 30°C, then inject the methanol solution of compound II and the hydrogen peroxide solution into the microchannel reactor at a molar ratio of 1:1.05 using metering pumps to mix and react. The reaction residence time is 5s. Samples of the material flowing out of the channel outlet are taken for testing. If the raw material is completely converted, the material is collected into the liquid tank.

[0092] 3) Set the temperature of the tubular reactor (filled with Ru / HZSM-5 catalyst) to 55℃, connect the metering pump to the feed tank, and connect the gas flow meter to the air cylinder. Set the flow rate so that the molar ratio of Formula III compound to oxygen in the air is 1:1.1. First, open the gas phase valve to release air and control the system pressure to 1MPa. Then, start the pump to pump the material into the tubular reactor for reaction. The residence time in the tubular reactor is about 2 minutes.

[0093] 4) The reaction liquid flowing out of the tubular reactor is separated by a gas-liquid separator, and the liquid phase is sampled and tested. The reaction of compound III is complete; the liquid material is collected into a liquid treatment tank.

[0094] 5) Add 1.5L of water to the liquid treatment tank, stir thoroughly, filter, and dry to obtain 379.4g of white solid sulfonylpyrazol (compound I), with a yield of 95.2% and a purity of 98.2%.

[0095] It can be seen that the catalyst using Ru as the single active ingredient exhibits a faster catalytic reaction rate, with a reaction residence time of only 2 minutes, resulting in complete sulfoxide conversion. However, the selectivity is reduced, leading to a situation where the conversion rate is high but the content and yield are low.

[0096] Example 13

[0097] This example illustrates the synthesis of sulfonylpyrazine.

[0098] 1) Material preparation: At room temperature, dissolve compound II (359.3 g, 1 mol, 1 eq) in 1.5 L of methanol and temporarily store it in a storage tank; place hydrogen peroxide solution (80.1 g, 27.5%, 1.05 mol, 1.05 eq) in another storage tank;

[0099] 2) Preheat the microchannel reactor to 30°C, then inject the methanol solution of compound II and the hydrogen peroxide solution into the microchannel reactor at a molar ratio of 1:1.05 using metering pumps to mix and react. The reaction residence time is 5s. Samples of the material flowing out of the channel outlet are taken for testing. If the raw material is completely converted, the material is collected into the liquid tank.

[0100] 3) Set the temperature of the tubular reactor (filled with Cu / HZSM-5 catalyst) to 55℃, connect the metering pump to the feed tank, and connect the gas flow meter to the air cylinder. Set the flow rate so that the molar ratio of Formula III compound to oxygen in the air is 1:1.1. First, open the gas phase valve to release air and control the system pressure to 1MPa. Then, start the pump to pump the material into the tubular reactor for reaction. The residence time in the tubular reactor is about 3 minutes.

[0101] 4) The reaction liquid flowing out of the tubular reactor is separated by a gas-liquid separator, and the liquid phase is sampled and tested. The remaining compound of Formula III (sulfoxide intermediate) is about 12%; the liquid material is collected into the liquid treatment tank.

[0102] 5) Add 1.5L of water to the liquid treatment tank, stir thoroughly, filter, and dry to obtain 383.1g of white solid sulfonylpyrazol (compound of formula I), with a yield of 84.3% and a purity of 86.1%.

[0103] Figure 2 The liquid-phase trace spectrum of the reaction is shown. The peak position of sulfoxide is 1.328 min, with a content of approximately 11.795%; the peak position of sulfonylpyrazine is 1.786 min. Using Cu / HZSM-5 as a catalyst, compared with the Ru-Cu / HZSM-5 catalyst, the catalytic activity is lower, and the sulfoxide is not completely converted.

[0104] Example 14

[0105] This invention illustrates the synthesis of sulfonylpyrazine.

[0106] 1) Material preparation: At room temperature, dissolve compound II (359.3 g, 1 mol, 1 eq) in 1.5 L of methanol and temporarily store it in a storage tank; place hydrogen peroxide solution (80.1 g, 27.5%, 1.05 mol, 1.05 eq) in another storage tank;

[0107] 2) Preheat the microchannel reactor to 30°C, then inject the methanol solution of compound II and the hydrogen peroxide solution into the microchannel reactor at a molar ratio of 1:1.05 using metering pumps to mix and react. The reaction residence time is 5s. Samples of the material flowing out of the channel outlet are taken for testing. If the raw material is completely converted, the material is collected into the liquid tank.

[0108] 3) Set the temperature of the tubular reactor (filled with Ag / HZSM-5 catalyst) to 55℃, connect the metering pump to the feed tank, and connect the gas flow meter to the air cylinder. Set the flow rate so that the molar ratio of Formula III compound to oxygen in the air is 1:1.1. First, open the gas phase valve to release air and control the system pressure to 1MPa. Then, start the pump to pump the material into the tubular reactor for reaction. The residence time in the tubular reactor is about 3 minutes.

[0109] 4) The reaction liquid flowing out of the tubular reactor is separated by a gas-liquid separator, and the liquid phase is sampled and tested. The remaining amount of compound III (sulfoxide intermediate) is about 5%. The liquid material is collected into the liquid treatment tank.

[0110] 5) Add 1.5L of water to the liquid treatment tank, stir thoroughly, filter, and dry to obtain 374.8g of white solid sulfonylpyrazol (compound I), with a yield of 88.5% and a purity of 92.4%.

[0111] Figure 3 The liquid-phase tracking spectrum of the reaction is shown. The peak position of sulfoxide is 1.336 min, with a content of approximately 5.419%; the peak position of sulfonylpyrazine is 1.802 min. Using Ag / HZSM-5 as a catalyst, the catalytic activity was slightly lower than that of the Ru-Cu / HZSM-5 catalyst, and the sulfoxide was not completely converted.

[0112] Example 15

[0113] Sulfonazole was synthesized according to the method of Example 1, except that methanol in step 1) was replaced with acetonitrile.

[0114] The final yield was 380.3g of white solid sulfonylpyrazole, with a yield of 96.3% and a purity of 99.1%.

[0115] Example 16

[0116] Sulfonazole was synthesized according to the method of Example 1, except that methanol in step 1) was replaced with N,N-dimethylformamide.

[0117] The final yield was 381.8g of white solid sulfonylpyrazole, with a yield of 96.6% and a purity of 99.0%.

[0118] A comparison of the product content and yield shows that using acetonitrile and N,N-dimethylformamide as solvents is not significantly different from using methanol. Considering both production cost and final yield, using methanol as the solvent is the best option.

[0119] Example 17

[0120] Sulfonazole was synthesized according to the method of Example 1, except that the residence time of the reaction solution in the tubular reactor in step 3) was approximately 2.5 min.

[0121] The liquid phase separated in step 4) was sampled and analyzed. Compound III (sulfoxide intermediate) remained at 0.5%. Finally, 378.6 g of white solid sulfonylpyrazol was obtained, with a yield of 95.2% and a purity of 98.4%.

[0122] This indicates that shortening the residence time in the tubular reactor results in incomplete conversion of intermediate form III compounds, leading to lower content and yield.

[0123] Example 18

[0124] Sulfonazole was synthesized according to the method of Example 1, except that the residence time of the reaction solution in the tubular reactor in step 3) was about 5 min.

[0125] The liquid phase separated in step 4) was sampled and analyzed, and the reaction of compound III (sulfoxide intermediate) was complete. Finally, 379.9 g of white solid sulfonylpyrazol was obtained, with a yield of 96.4% and a purity of 99.3%.

[0126] This indicates that extending the residence time in the tubular reactor has little effect on the yield and content.

[0127] Example 19

[0128] Sulfonazole was synthesized according to the method in Example 1, except that the set temperature of the tubular reactor in step 3) was increased to 65°C.

[0129] The liquid phase separated in step 4) was sampled and analyzed, and the reaction of compound III (sulfoxide intermediate) was complete. Finally, 382.2 g of white solid sulfonylpyrazol was obtained, with a yield of 95.9% and a purity of 98.2%.

[0130] This indicates that increasing the reaction temperature in the tubular reactor tends to decrease the content of sulfonylpyrazine, and that high temperatures cause the formation of impurities.

[0131] Example 20

[0132] Sulfonazole was synthesized according to the method in Example 1, except that the catalyst in step 3) was replaced with a Ru-Cu / Al2O3 catalyst.

[0133] The liquid phase sample separated in step 4) was analyzed, and approximately 7% of compound III (sulfoxide intermediate) remained. Finally, 377.9 g of white solid sulfonylpyrazol was obtained, with a yield of 87.2% and a purity of 90.3%.

[0134] Figure 4 The liquid-phase tracking spectrum of the reaction is shown. The peak position of sulfoxide is 1.308 min, with a content of approximately 6.781%; the peak position of sulfonylpyrazine is 1.762 min. Using Ru-Cu / Al₂O₃ as a catalyst, the catalytic activity is worse than that of the Ru-Cu / HZSM-5 catalyst, and the sulfoxide is not completely converted.

[0135] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for synthesizing sulfonylpyrazole, characterized in that, The method includes the following steps: (1) The feed solution of compound II and the first oxidant are introduced into a microchannel reactor to carry out the first reaction, and a feed solution containing compound III is obtained; (2) The feed liquid containing the compound of formula III and the second oxidant are introduced into a tubular reactor to carry out the second reaction to obtain the compound of formula I; 2. The method according to claim 1, wherein, In step (1), the liquid of the compound of formula II includes the compound of formula II and an organic solvent; Preferably, the organic solvent is selected from at least one of methanol, ethanol, acetonitrile, tetrahydrofuran, N,N-dimethylformamide and N,N-dimethylacetamide, preferably methanol or acetonitrile, and more preferably methanol.

3. The method according to claim 1 or 2, wherein, In step (1), the first oxidant is hydrogen peroxide; Preferably, the molar ratio of the compound of formula II to the first oxidant is 1:1-1.2, more preferably 1:1.

05.

4. The method according to any one of claims 1-3, wherein, The temperature of the first reaction is 0-100℃, preferably 25-30℃; Preferably, the time for the first reaction is 3-20 seconds, more preferably 3-7 seconds, and even more preferably 5 seconds.

5. The method according to any one of claims 1-4, wherein, In step (2), the tubular reactor is loaded with a metal-based solid catalyst; Preferably, the active component of the metal-based solid catalyst is selected from at least one of Ru, Ag, and Cu, and more preferably Ru and Cu; Preferably, the support for the metal-based solid catalyst is selected from molecular sieves and / or activated alumina, preferably molecular sieves, and more preferably HZSM-5 molecular sieves.

6. The method according to claim 5, wherein, The preparation method of the metal-based solid catalyst includes: impregnating a support in a soluble metal salt solution, and drying and calcining the support after impregnation to obtain the metal-based solid catalyst.

7. The method according to claim 6, wherein, The metal salt in the soluble metal salt solution is selected from at least one of ruthenium chloride, ruthenium acetate, ruthenium nitrate, silver nitrate, copper chloride, and copper nitrate, preferably ruthenium acetate and copper nitrate; Preferably, the impregnation conditions include: a temperature of 30-60°C, preferably 40°C; and a time of 12-30 hours, preferably 16 hours. Preferably, the drying conditions include: a temperature of 90-120℃, preferably 110℃; and a time of 5-8 hours, preferably 6 hours. Preferably, the roasting conditions include: a temperature of 200-500℃, more preferably 250-300℃; and a time of 2-5 hours, more preferably 4 hours.

8. The method according to any one of claims 1-7, wherein, In step (2), the second oxidant is air and / or oxygen; Preferably, the molar ratio of the compound of formula III to the second oxidant is 1:1-2, more preferably 1:1.

1.

9. The method according to any one of claims 1-8, wherein, In step (2), the temperature of the second reaction is 30-90℃, preferably 50-55℃; Preferably, the pressure of the second reaction is 0.5-3 MPa, and more preferably 1 MPa; Preferably, the second reaction takes 2-5 minutes, more preferably 3 minutes.

10. The method according to any one of claims 1-9, wherein, In step (2), the product of the second reaction is subjected to gas-liquid separation, and water is added to the obtained liquid material for stirring, filtration, and drying to obtain compound I.

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