A method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt

Abstract

The invention discloses a method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazole-5-ketone metal salt, the method uses a compound of formula 1 as a raw material, forms a salt with a metal carbonate in water, obtains a compound of formula 2, the compound of formula 2 and hydrogen peroxide are subjected to an oxidation reaction in a microchannel reactor to synthesize a compound of formula 3, after the reaction is completed, the water is removed by negative pressure, and the product is obtained by drying to a moisture content of <0.1%. The method of the present invention uses water as a single solvent, is easy to recycle, and is simple to apply. The raw material is more soluble in water after being formed into salt, increases contact with hydrogen peroxide, greatly improves the reaction rate, and hydrogen peroxide is less in excess, suitable for industrial production, and uses a microchannel reactor as a reaction device, and can be directly seamlessly amplified for production, the method has low production cost, simple process, no three wastes, and has a high industrial value.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemical product synthesis, and specifically relates to a method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt. Background Art

[0002] 3-Methyl-1-phenyl-1,2,4-triazole-5-one metal salt is an important intermediate for the synthesis of sulfentrazone, and its structural formula is shown below:

[0003]

[0004] In the existing public literature, there are many methods for preparing the intermediate: using phenylhydrazine as the raw material, condensing acetaldehyde to form a hydrazone, then cyclizing with cyanate to form an alkanone, and finally oxidizing it; or using a one-step synthesis method using special raw materials.

[0005] CN104672157B discloses a method for preparing aryl triazolinone: 5-methyl-2-phenyl-1,2,4-triazolidine-3-one is dissolved in a tert-butyl alcohol / water mixed solvent, activated carbon (specific surface area 2000-3000m 2 / g, micropore diameter 0.5-3.0nm) as a catalyst, after sufficient stirring, 27.5wt% hydrogen peroxide (excess 100%) is added dropwise at 70°C, the temperature is kept for reaction after the addition, the activated carbon is removed by hot filtration, the tert-butyl alcohol is removed, and the temperature is lowered for crystallization, and the yield is 98.7%. This method uses hydrogen peroxide to directly oxidize the cyclocompound, and the yield is very high, but it is necessary to remove the activated carbon by hot filtration, remove the tert-butyl alcohol at high temperature, and the hydrogen peroxide is 100% excessive. In the post-processing operation, the tert-butyl alcohol is easily volatilized under negative pressure, causing the product to precipitate and block the filter; the excess hydrogen peroxide decomposes under high temperature reflux, which poses a safety risk.

[0006] CN1035433C discloses a synthesis method for forming a triazolinone ring in tert-butyl alcohol: phenylhydrazine is reacted with aldehyde in a tert-butyl alcohol / water mixture to form a hydrazone, and then reacted with sodium cyanate to form an alkane, and finally a 12.4% sodium hypochlorite solution is added dropwise at a temperature below 10°C, and reacted at room temperature for 18 hours after the addition is completed. After removing the tert-butyl alcohol, the product is cooled and precipitated, and filtered and washed to obtain a product with a content of 98.9%, with a yield of about 93.1%. In this method, sodium hypochlorite is prepared on the spot, and the content needs to be relatively accurate. The reaction time is as long as 18 hours, the equipment utilization rate is low, and the reaction produces sodium chloride, which is easily wrapped in the product, resulting in unstable content; low-concentration sodium hypochlorite results in a large amount of reaction wastewater and high salt content.

[0007] CN112225705B discloses a method for preparing 3-methyl-1-phenyl-1H-1,2,4-triazole-5(4H)-one: the method uses alkanone as raw material, tert-butyl alcohol as solvent, air as oxidant, catalytic oxidation with vanadium pentoxide at 40°C to 50°C, reaction time 4-10h, the obtained product content is 93-95%, the yield is 85-90%, the method of the invention is simple to operate, and the amount of three wastes is small. The method uses air oxidation, although it reduces reaction wastewater and waste residue, but the long reaction time reduces the equipment utilization rate, the yield and product content are low, which not only affects the subsequent reaction, but also the impurities generated by the reaction enter the wastewater, increasing the pressure on environmental protection.

[0008] CN114634454A discloses a method for preparing a 2,4-dichlorophenyltriazolinone compound: the method uses 2,4-dichlorophenylhydrazine and ethyl(E)-N-(ethoxycarbonyl)acetimidate As raw material, xylene is used as solvent, and the by-product alcohol is removed while refluxing. After 10 hours, the solvent is recovered by desolventizing, cooling, and filtering to obtain 2,4-dichlorophenyltriazolinone, with a product content of 98.0% and a yield of 88.1%. This method uses a one-step method to synthesize triazolinone, which is novel and easy to operate. However, the reaction time is long, and the raw material ethyl(E)-N-(ethoxycarbonyl)acetimidate is not easy to obtain (there is no industrial product yet), which makes industrialization difficult. Summary of the invention

[0009] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt which is easy to industrialize, convenient and fast, and has readily available raw materials.

[0010] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0011] A method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt, wherein the method uses a compound of formula 1 as a raw material, forms a salt with a metal carbonate in water to obtain a compound of formula 2, and the compound of formula 2 is subjected to an oxidation reaction with hydrogen peroxide in a microchannel reactor to synthesize a compound of formula 3. After the reaction is completed, water is removed under negative pressure, and the product is dried to a moisture content of <0.1% to obtain a 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt product. The product is a qualified product that can be used for the next step reaction.

[0012]

[0013] In the above method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt, preferably, the molar ratio of the compound of formula 2 to hydrogen peroxide is 1:1.05-1.2.

[0014] In the above-mentioned method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt, preferably, the mass fraction of the hydrogen peroxide is 30% to 50%.

[0015] In the above-mentioned method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt, preferably, the metal carbonate is one or more of potassium bicarbonate, sodium bicarbonate, potassium carbonate and sodium carbonate.

[0016] In the above-mentioned method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt, preferably, the temperature of salt formation is 20°C to 40°C.

[0017] In the above-mentioned method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt, preferably, the salt formation time is 2h to 4h.

[0018] In the above-mentioned method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt, preferably, the temperature of the oxidation reaction is 20°C to 40°C.

[0019] In the above-mentioned method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt, preferably, the negative pressure is vacuum-0.09 MPa.

[0020] In the method of the present invention, the amount of water is sufficient to form salt.

[0021] In the method of the present invention, when a microchannel reactor is used, the compound of formula 2 and hydrogen peroxide are pumped into the reaction chamber through two channels of the microchannel reactor respectively, and react in the reaction chamber.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] 1) The present invention selects water as the single solvent, which is easy to recycle and simple to apply.

[0024] 2) The raw materials of the present invention are more soluble in water after being salted, which increases the contact with hydrogen peroxide and greatly improves the reaction rate.

[0025] 3) The hydrogen peroxide of the present invention has a small excess, and the post-treatment is safe and simple, and is suitable for industrial production.

[0026] 4) The present invention uses a microchannel reactor as a reaction device, which has basically no amplification effect and can directly carry out seamless amplification production.

[0027] 5) The present invention has low production cost, simple process, no three wastes generated, and high industrial value. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with specific preferred embodiments, but the protection scope of the present invention is not limited thereby. In the following embodiments, the microchannel reactor is a microchannel glass reactor (LFR) produced by Corning, but is not limited to the microchannel reactor, and the remaining reagents or equipment are conventional commercially available.

[0029] The reaction paths of the following examples are as follows:

[0030]

[0031] Example 1

[0032] A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt of the present invention comprises the following steps:

[0033] 178.8g (99.0%, 1.0mol) 5-methyl-2-phenyl-1,2,4-triazol-3-one (Formula 1), 102g (98.0%, 1mol) potassium bicarbonate and 200g water were placed in a three-necked reaction bottle with a stirrer and a thermometer, and the temperature was raised to 30-40°C and stirred for 2h to obtain the potassium salt shown in Formula 2. After the system was completely clarified, the temperature of the microchannel reactor was controlled at 30-40°C, and the potassium salt (Formula 2) and 30wt% hydrogen peroxide were pumped into the reactor at a constant rate at a molar ratio of 1:1.1 by a plunger pump to ensure that the material stayed in the reactor for 3min. After the feeding was completed, the reaction solution was sampled and analyzed, and the conversion rate of Formula 1 was ≥99.5%, and the reaction was completed. The vacuum was controlled to be about -0.09MPa to remove water, and the obtained solid (Formula 3) was dried. The water content was <0.1% to be a qualified product, which was directly used for the next step of synthesis. The product content was 97.2% (calculated as potassium salt component) and the yield was 95.3%. The recycled water can be used directly for application.

[0034] Example 2

[0035] A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt of the present invention comprises the following steps:

[0036] 178.8g (99.0%, 1.0mol) 5-methyl-2-phenyl-1,2,4-triazol-3-one (Formula 1), 102g (98.0%, 1mol) potassium bicarbonate and 200g water were placed in a three-necked reaction bottle with a stirrer and a thermometer, and the temperature was raised to 30-40°C and stirred for 2h to obtain the potassium salt shown in Formula 2. After the system was completely clarified, the temperature of the microchannel reactor was controlled at 20-30°C, and the potassium salt (Formula 2) and 50wt% hydrogen peroxide were pumped into the reactor at a constant rate at a molar ratio of 1:1.05 by a plunger pump to ensure that the material stayed in the reactor for 1min. After the feeding was completed, the reaction solution was sampled and analyzed, and the conversion rate of Formula 1 was ≥99.5%, and the reaction was completed. The vacuum was controlled to be about -0.09MPa to remove water, and the obtained solid (Formula 3) was dried. The water content <0.1% was qualified, the product content was 99.0% (calculated as potassium salt component), and the yield was 98.1%. The recycled water can be used directly for application.

[0037] Example 3

[0038] A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt of the present invention comprises the following steps:

[0039] 178.8g (99.0%, 1.0mol) 5-methyl-2-phenyl-1,2,4-triazol-3-one (Formula 1), 85.7g (98.0%, 1mol) sodium bicarbonate and 200g water were placed in a three-necked reaction bottle with a stirrer and a thermometer, and the temperature was raised to 30-40°C and stirred for 4h to obtain the sodium salt shown in Formula 2. After the system was completely clarified, the temperature of the microchannel reactor was controlled at 20-30°C, and the sodium salt (Formula 2) and 50wt% hydrogen peroxide were pumped into the reactor at a constant rate at a molar ratio of 1:1.1 by a plunger pump to ensure that the material stayed in the reactor for 1.8min. After the feeding was completed, the reaction solution was sampled and analyzed, and the conversion rate of Formula 1 was ≥99.5%, and the reaction was completed. The vacuum was controlled to be about -0.09MPa to remove water, and the obtained solid (Formula 3) was dried. The water content <0.1% was qualified, the product content was 97.0% (calculated as sodium salt component), and the yield was 91.4%. The recycled water can be used directly for application.

[0040] Example 4

[0041] A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt of the present invention comprises the following steps:

[0042] 178.8g (99.0%, 1.0mol) 5-methyl-2-phenyl-1,2,4-triazol-3-one (Formula 1), 85.7g (98.0%, 1mol) sodium bicarbonate and 200g water were placed in a three-necked reaction bottle with a stirrer and a thermometer, and the temperature was raised to 30-40°C and stirred for 4h to obtain the sodium salt shown in Formula 2. After the system was completely clarified, the temperature of the microchannel reactor was controlled at 30-40°C, and the sodium salt (Formula 2) and 30wt% hydrogen peroxide were pumped into the reactor at a constant rate at a molar ratio of 1:1.2 by a plunger pump to ensure that the material stayed in the reactor for 3min. After the feeding was completed, the reaction solution was sampled and analyzed, and the conversion rate of Formula 1 was ≥99.3%, and the reaction was completed. The vacuum was controlled to be about -0.09MPa to remove water, and the obtained solid (Formula 3) was dried. The water content <0.1% was qualified, the product content was 97.2% (calculated as sodium salt component), and the yield was 90.4%. The recycled water can be used directly for application.

[0043] Example 5

[0044] A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt of the present invention comprises the following steps:

[0045] 178.8g (99.0%, 1.0mol) 5-methyl-2-phenyl-1,2,4-triazole-3-one (Formula 1), 140.8g (98.0%, 1mol) potassium carbonate, 200g water are placed in a three-necked reaction bottle with a stirrer and a thermometer, heated to 30-40°C and stirred for 4h. After the system is completely clarified, the temperature of the microchannel reactor is controlled at 30-40°C, and potassium salt (Formula 2) and 30wt% hydrogen peroxide are pumped into the reactor at a constant rate of 1:1.1 by a plunger pump, and the material is ensured to stay in the reactor for 3min. After the feeding is completed, the reaction liquid is sampled and analyzed, and the conversion rate of Formula 1 is ≥99.5%, and the reaction is completed. The vacuum is controlled to be about -0.09MPa to remove water, and the solid (Formula 3) obtained by drying is qualified only when the water content is <0.1%, and the product content is 97.0% (calculated as potassium salt component), and the yield is 91.3%. The recovered water can be directly used for application.

[0046] Example 6

[0047] A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt of the present invention comprises the following steps:

[0048] 178.8g (99.0%, 1.0mol) 5-methyl-2-phenyl-1,2,4-triazole-3-one (Formula 1), 140.8g (98.0%, 1mol) potassium carbonate, 200g water are placed in a three-necked reaction bottle with a stirrer and a thermometer, heated to 30-40°C and stirred for 4h. After the system is completely clarified, the temperature of the microchannel reactor is controlled at 20-30°C, and potassium salt (Formula 2) and 50wt% hydrogen peroxide are pumped into the reactor at a constant rate of 1:1.05 by a plunger pump, and the material residence time in the reactor is ensured to be 1min. After the feeding is completed, the reaction liquid is sampled and analyzed, and the conversion rate of Formula 1 is ≥99.5%, and the reaction is completed. The vacuum is controlled to be about -0.09MPa to remove water, and the solid (Formula 3) obtained by drying is qualified only when the water content is <0.1%, and the product content is 98.2% (calculated as potassium salt component), and the yield is 94.1%. The recovered water can be directly used for re-use.

[0049] Example 7

[0050] A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt of the present invention comprises the following steps:

[0051] 178.8g (99.0%, 1.0mol) 5-methyl-2-phenyl-1,2,4-triazole-3-one (Formula 1), 108.1g (98.0%, 1mol) sodium carbonate, 200g water are placed in a three-necked reaction bottle with a stirrer and a thermometer, heated to 30-40°C and stirred for 4h. After the system is completely clarified, the temperature of the microchannel reactor is controlled at 30-40°C, and the sodium salt (Formula 2) and 50wt% hydrogen peroxide are pumped into the reactor at a constant rate of 1:1.1 by a plunger pump, and the material is ensured to stay in the reactor for 2min. After the feeding is completed, the reaction liquid is sampled and analyzed, and the conversion rate of Formula 1 is ≥97.5%, and the reaction is completed. The vacuum is controlled to be about -0.09MPa to remove water, and the solid (Formula 3) obtained by drying is qualified only when the water content is <0.1%, and the product content is 95.0% (calculated as sodium salt component), and the yield is 90.7%. The recovered water can be directly used for application.

[0052] Example 8

[0053] A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt of the present invention comprises the following steps:

[0054] 178.8g (99.0%, 1.0mol) 5-methyl-2-phenyl-1,2,4-triazole-3-one (Formula 1), 108.1g (98.0%, 1mol) sodium carbonate, 200g water are placed in a three-necked reaction bottle with a stirrer and a thermometer, heated to 30-40°C and stirred for 4h. After the system is completely clarified, the temperature of the microchannel reactor is controlled at 30-40°C, and the sodium salt (Formula 2) and 30wt% hydrogen peroxide are pumped into the reactor at a constant rate of 1:1.2 by a plunger pump, and the material is ensured to stay in the reactor for 4min. After the feeding is completed, the reaction liquid is sampled and analyzed, and the conversion rate of Formula 1 is ≥97.5%, and the reaction is completed. The vacuum is controlled to be about -0.09MPa to remove water, and the solid (Formula 3) obtained by drying is qualified only when the water content is <0.1%, and the product content is 95.0% (calculated as sodium salt component), and the yield is 89.8%. The recovered water can be directly used for application.

[0055] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for continuously synthesizing a 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt, characterized in that: The method uses a compound of formula 1 as a raw material, forms a salt with a metal carbonate in water to obtain a compound of formula 2, wherein the metal carbonate is M2CO3 and / or MHCO3, and the compound of formula 2 is subjected to an oxidation reaction with hydrogen peroxide in a microchannel reactor to synthesize a compound of formula 3. After the reaction is completed, water is removed under negative pressure, and the compound is dried to a moisture content of less than 0.1% to obtain a 3-methyl-1-phenyl-1,2,4-triazole-5-one metal salt product.

2. The method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt according to claim 1, characterized in that: The molar ratio of the compound of formula 2 to hydrogen peroxide is 1:1.05-1.

2.

3. The method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt according to claim 2, characterized in that: The mass fraction of the hydrogen peroxide is 30% to 50%.

4. The method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt according to any one of claims 1 to 3, characterized in that: The metal carbonate is one or more of potassium bicarbonate, sodium bicarbonate, potassium carbonate and sodium carbonate.

5. The method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt according to any one of claims 1 to 3, characterized in that: The temperature of the salt formation is 20°C to 40°C.

6. The method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt according to any one of claims 1 to 3, characterized in that: The salt formation time is 2h to 4h.

7. The method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt according to any one of claims 1 to 3, characterized in that: The temperature of the oxidation reaction is 20°C to 40°C.

8. The method for continuously synthesizing 3-methyl-1-phenyl-1,2,4-triazol-5-one metal salt according to any one of claims 1 to 3, characterized in that: The negative pressure is vacuum-0.09MPa.

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