Novel synthesis process of pyridaben

Abstract

The invention relates to a novel method for synthesizing pyridaben, which comprises the following steps of: firstly, carrying out condensation reaction on dichloropyridazinone and p-tert-butyl benzyl mercaptan in the presence of an acid-binding agent and a non-water-soluble organic solvent to obtain pyridaben, then carrying out alkali washing, acid washing and water washing treatment, and finally crystallizing and drying to obtain a finished product. The process for synthesizing pyridaben through a dichloropyridazinone method is optimized, the product yield and purity are improved, and the method is suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticides, and particularly relates to a new method for synthesizing pyridaben. Background Art

[0002] Pyridaben (chemical name: 2-tert-butyl-5-(4-tert-butylbenzylthio)-4-chloro-2H-pyridazin-3-one, English name: Pyridaben, CAS: 96489-71-3, molecular formula: C 19 H 25 ClN 2 OS, molecular weight: 364.93), also known as pyridaphenthione and nitrothal-isopropyl, is a broad-spectrum and contact acaricide, which can be used to control a variety of phytophagous mites. It has good effects on the entire growth period of mites, namely eggs, larvae, nymphs and adults, and also has obvious quick-killing effects on adult mites in the mobile period. Its chemical structural formula is as follows:

[0003]

[0004] At present, there are mainly two synthetic process routes for pyridaben:

[0005] Route 1: Using methanol as a solvent, adding intermediate dichloropyridazinone and p-tert-butylbenzyl mercaptan, and dropping a methanol solution of sodium methoxide to react to synthesize pyridaben. Then, crystallization and centrifugation are carried out to separate out the crude powder, which is then put into a kettle and washed three times with hot water, and then dried and packaged to obtain the finished pyridaben technical material.

[0006] Route 2: Using methanol as a solvent, adding intermediate dichloropyridazinone and p-tert-butylbenzyl mercaptan, and dropping a methanol solution of sodium methoxide to react to synthesize pyridaben. Then, the solvent methanol is removed, petroleum ether is added for dissolution and washing, and then most of the solvent petroleum ether is removed, and it is put into a crystallization kettle, centrifuged and dried to obtain the finished pyridaben technical material.

[0007] The solvents for both routes are methanol, and the acid-binding agent is a methanol solution of sodium methoxide. Sodium methoxide is relatively dangerous and costly, and desalting by washing is required after synthesizing pyridaben. The content of the technical material in Route 1 is relatively low, with a large amount of manual labor and wastewater; the content of the technical material in Route 2 is relatively high, with high energy consumption and high cost. Therefore, it is necessary to develop an effective method for synthesizing pyridaben. Summary of the Invention

[0008] The present invention provides a new method for synthesizing pyridaben. By changing the acid-binding agent and reaction solvent for the condensation reaction of dichloropyridazinone and p-tert-butylbenzyl mercaptan, and combining with the post-treatment process of acid-base washing, while simplifying the process and reducing the three wastes, the yield and content of the finished product are effectively improved.

[0009] The technical solution adopted to achieve the above-mentioned invention purpose is as follows:

[0010] A new method for synthesizing pyridaben, comprising the following steps:

[0011] (1) Under the condition of the simultaneous presence of an acid-binding agent and a water-insoluble organic solvent, condense dichloropyridazinone with p-tert-butylbenzyl mercaptan to obtain pyridaben;

[0012] (2) Wash the pyridaben obtained in step (1) successively with an alkali solution, an acid solution, and then with water until neutral to obtain a crude pyridaben product;

[0013] (3) Crystallize and dry the crude pyridaben product obtained in step (2) to obtain the finished pyridaben product.

[0014] The above cyclization reaction is as follows:

[0015]

[0016] Among them, the temperature of the condensation reaction in step (1) is -10°C to 38°C.

[0017] Among them, the solution concentration of dichloropyridazinone in step (1) is 3 to 20% (g / v).

[0018] Among them, the acid-binding agent in step (1) is selected from at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, potassium tert-butoxide, sodium tert-butoxide, triethylamine, and sodium hydride.

[0019] Preferably, the acid-binding agent is selected from at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

[0020] Among them, the water-insoluble organic solvent in step (1) is selected from at least one of dichloromethane, dichloroethane, chloroform, solvent oil, ether, diphenyl ether, petroleum ether, isopropyl ether, cyclohexane, hexane, n-butane, acetonitrile, methyl acetate, ethyl acetate, and pyridine.

[0021] Preferably, the water-insoluble organic solvent is selected from at least one of dichloroethane, dichloromethane, solvent oil, and petroleum ether.

[0022] Among them, the alkali solution in step (2) is an aqueous sodium hydroxide solution with a concentration of 3 to 32% (g / v).

[0023] Among them, the acid solution in step (2) is an aqueous sulfuric acid solution with a concentration of 3 to 30% (g / v).

[0024] Among them, the crystallization solvent in step (3) is the same as the condensation reaction solvent in step (1).

[0025] The technical solution of the present invention has at least the following beneficial technical effects:

[0026] 1. Compared with the prior art, the present invention uses a new acid-binding agent instead of sodium methoxide, reducing the risk.

[0027] 2. In the condensation reaction of the present invention, a water-insoluble organic solvent is used, and the solvent used can be the same as the solvent in the synthesis of pyridazinone in the previous process. In this way, the desolvation process is reduced, saving energy consumption.

[0028] 3. By changing the acid-binding agent and reaction solvent in the condensation reaction of dichloropyridazinone and p-tert-butylbenzyl mercaptan, and combining with the post-treatment process of acid-base washing, the present invention effectively improves the yield and content of the finished product. The product purity is greater than 98.5%, and the yield is above 94%. Detailed implementation mode

[0029] The following is a further description of the present invention in conjunction with specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0030] In the embodiment of the present invention, the determination of the content of pyridaben is carried out by using the standard detection method of pyridaben technical GB / T 28130-2011. The high performance liquid chromatography conditions are as follows: using octadecylsilane chemically bonded silica gel as the filler, with acetonitrile: water = (85:15) as the mobile phase, the detection wavelength is 240nm, and it is determined according to the "High Performance Liquid Chromatography Method" according to law, and calculated by the external standard method.

[0031] Example 1

[0032] Add 760 g (content 10%, 0.34 mol) of dichloropyridazinone dichloroethane solution to a four-necked flask, slowly add 68 g (content 96%, 0.36 mol) of p-tert-butylbenzyl mercaptan, cool down to 10 °C, and slowly add 52 g (content 30%, 0.39 mol) of sodium hydroxide aqueous solution at a constant speed. Keep warm for 30 minutes, add the lower layer of the liquid to 13 g (content 30%, 0.1 mol) of sodium hydroxide aqueous solution for washing, then wash with 100 g (content 10%, 0.1 mol) of sulfuric acid aqueous solution, add 100 g of water for washing until pH = 7, remove 520 g of dichloroethane solvent, cool down to 0 °C for crystallization, and then filter by suction to obtain wet pyridaben powder. After drying, 120 g of pyridaben is obtained, with a content of 99.0% and a yield of 94.7%.

[0033] Example 2

[0034] Add 760 g (content 10%, 0.34 mol) of dichloropyridazinone dichloromethane solution to a four-necked flask, slowly add 68 g (content 96%, 0.36 mol) of p-tert-butylbenzyl mercaptan, cool down to 10 °C, and slowly add 72 g (content 30%, 0.38 mol) of potassium hydroxide aqueous solution at a uniform speed. Keep warm for 30 minutes. Wash the upper layer of the liquid material with 13 g (content 30%, 0.1 mol) of sodium hydroxide aqueous solution, then wash with 100 g (content 10%, 0.1 mol) of sulfuric acid aqueous solution, add 100 g of water and wash until pH = 7. Remove 550 g of dichloromethane solvent. Cool down to 20 °C, crystallize and then filter by suction to obtain wet pyridaben powder. After drying, 120.3 g of pyridaben is obtained, with a content of 98.9% and a yield of 94.8%.

[0035] Example 3

[0036] Add 760 g (content 10%, 0.34 mol) of dichloropyridazinone solvent oil solution to a four-necked flask, slowly add 68 g (content 96%, 0.36 mol) of p-tert-butylbenzyl mercaptan, cool down to 10 °C, and slowly add 52 g (content 15%, 0.19 mol) of sodium carbonate aqueous solution at a uniform speed. Keep warm for 30 minutes. Wash the lower layer of the liquid material with 13 g (content 30%, 0.1 mol) of sodium hydroxide aqueous solution, then wash with 100 g (content 10%, 0.1 mol) of sulfuric acid aqueous solution, add 100 g of water and wash until pH = 7. Remove 546 g of solvent oil. Cool down to 0 °C, crystallize and then filter by suction to obtain wet pyridaben powder. After drying, 121.3 g of pyridaben is obtained, with a content of 99.0% and a yield of 95.7%.

[0037] Example 4

[0038] Add 760 g (content 10%, 0.34 mol) of dichloropyridazinone petroleum ether solution to a four-necked flask, slowly add 68 g (content 96%, 0.36 mol) of p-tert-butylbenzyl mercaptan, cool down to 10 °C, and slowly add 109 g (content 30%, 0.39 mol) of sodium bicarbonate aqueous solution at a uniform speed. Keep warm for 30 minutes. Wash the upper layer of the liquid material with 13 g (content 30%, 0.1 mol) of sodium hydroxide aqueous solution, then wash with 100 g (content 10%, 0.1 mol) of sulfuric acid aqueous solution, add 100 g of water and wash until pH = 7. Remove 552 g of petroleum ether solvent. Cool down to 20 °C, crystallize and then filter by suction to obtain wet pyridaben powder. After drying, 121.5 g of pyridaben is obtained, with a content of 99.1% and a yield of 95.9%.

[0039] Example 5

[0040] Add 760 g (content 10%, 0.34 mol) of the dichloropyridazinone petroleum ether solution to a four-necked flask, slowly add 68 g (content 96%, 0.36 mol) of p-tert-butylbenzyl mercaptan, cool down to 10 °C, and slowly and uniformly add 52 g (content 30%, 0.39 mol) of sodium hydroxide aqueous solution. Keep warm for 30 minutes, wash the upper layer of the liquid with 13 g (content 30%, 0.1 mol) of sodium hydroxide aqueous solution, then wash with 100 g (content 10%, 0.1 mol) of sulfuric acid aqueous solution, add 100 g of water to wash until pH = 7, remove 555 g of the solvent petroleum ether, cool down to 20 °C, crystallize, and then filter by suction to obtain the wet powder of pyridaben. After drying, 122 g of pyridaben is obtained, with a content of 98.7% and a yield of 96.0%.

[0041] Comparative Example 1

[0042] Put 560 g (content 99%, 17.33 mol) of methanol into a four-necked flask, slowly add 80 g (content 95%, 0.34 mol) of dichloropyridazinone, then add 68 g (content 96%, 0.36 mol) of p-tert-butylbenzyl mercaptan, control the temperature at 0 - 25 °C, dropwise add 75 g (content 28%, 0.39 mol) of sodium methoxide methanol solution. After the dropping is completed, keep warm for 30 minutes, cool down to 0 °C, crystallize, and then filter by suction to obtain the wet powder of pyridaben. Add 100 g of hot water and rinse 3 times. After drying, 118.3 g of pyridaben is obtained, with a content of 95.1% and a yield of 89.7%.

[0043] Comparative Example 2

[0044] Put 560 g (content 99%, 17.33 mol) of methanol into a four-necked flask, slowly add 80 g (content 95%, 0.34 mol) of dichloropyridazinone, then add 68 g (content 96%, 0.36 mol) of p-tert-butylbenzyl mercaptan, control the temperature at 0 - 25 °C, dropwise add 75 g (content 28%, 0.39 mol) of sodium methoxide methanol solution. After the dropping is completed, keep warm for 30 minutes, heat up to remove methanol, then add 560 g of petroleum ether, wash with 13 g (content 30%, 0.1 mol) of sodium hydroxide aqueous solution, then wash with 100 g (content 10%, 0.1 mol) of sulfuric acid aqueous solution, add 100 g of water to wash until pH = 7, remove 440 g of the petroleum ether solvent, cool down to 0 °C, crystallize, and then filter by suction to obtain the wet powder of pyridaben. After drying, 113.2 g of pyridaben is obtained, with a content of 98.5% and a yield of 88.85%.

[0045] Comparative Example 3

[0046] 560 g (99% content, 17.33 mol) of petroleum ether was put into a four-necked flask, 80 g (95% content, 0.34 mol) of dichloropyridazinone was slowly added, then 68 g (96% content, 0.36 mol) of p-tert-butylbenzyl mercaptan was added. The temperature was controlled at 0 - 25 °C, and 75 g (28% content, 0.39 mol) of sodium methoxide methanol solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 minutes. The upper layer of the liquid was washed with 13 g (30% content, 0.1 mol) of sodium hydroxide aqueous solution, then washed with 100 g (10% content, 0.1 mol) of sulfuric acid aqueous solution, and then washed with 100 g of water until the pH was 7. 551 g of the solvent petroleum ether was removed. After cooling to 20 °C and crystallization, the wet powder of pyridaben was obtained by suction filtration. After drying, 112.8 g of pyridaben was obtained, with a content of 98.1% and a yield of 88.2%.

[0047] Comparative Example 4

[0048] 560 g (99% content, 17.33 mol) of methanol was put into a four-necked flask, 80 g (95% content, 0.34 mol) of dichloropyridazinone was slowly added, then 68 g (96% content, 0.36 mol) of p-tert-butylbenzyl mercaptan was added. The temperature was controlled at 0 - 25 °C, and 52 g (30% content, 0.39 mol) of sodium hydroxide aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 minutes. After cooling to 0 °C and crystallization, the wet powder of pyridaben was obtained by suction filtration. It was rinsed 3 times with 100 g of hot water. After drying, 125.2 g of pyridaben was obtained, with a content of 85.9% and a yield of 85.7%.

Claims

1. A new method for synthesizing pyridaben, comprising the following steps: (1) Under the simultaneous presence of an acid-binding agent and a water-insoluble organic solvent, condense dichloropyridazinone with p-tert-butylbenzyl mercaptan to obtain pyridaben; (2) Wash the pyridaben obtained in step (1) successively with an alkali solution, an acid solution, and then wash with water until neutral to obtain a crude pyridaben product; (3) Crystallize and dry the crude pyridaben product obtained in step (2) to obtain the finished pyridaben product.

2. According to the method described in claim 1, wherein the temperature of the condensation reaction described in step (1) is -10°C to 38°C.

3. According to the method described in claim 1, wherein the solution concentration of dichloropyridazinone described in step (1) is 3% to 20%.

4. According to the method described in claim 1, wherein the acid-binding agent described in step (1) is selected from at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, potassium tert-butoxide, sodium tert-butoxide, triethylamine, and sodium hydride.

5. According to the method described in claim 4, wherein the acid-binding agent is selected from at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

6. According to the method described in claim 1, wherein the water-insoluble organic solvent described in step (1) is selected from at least one of dichloromethane, dichloroethane, chloroform, solvent oil, ether, diphenyl ether, petroleum ether, isopropyl ether, cyclohexane, hexane, n-butane, acetonitrile, methyl acetate, ethyl acetate, and pyridine.

7. According to the method described in claim 6, wherein the water-insoluble organic solvent is selected from dichloroethane or cyclohexane.

8. According to the method described in claim 1, wherein the alkali solution described in step (2) is an aqueous sodium hydroxide solution with a concentration of 3% to 32%.

9. According to the method described in claim 1, wherein the acid solution has a concentration of 3% to 30% sulfuric acid aqueous solution.

10. According to the method described in claim 1, wherein the crystallization solvent in step (3) is the same as the condensation reaction solvent in step (1).

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