Method for preparing pyriproxyfen without solvent

Abstract

The invention relates to the technical field of pyriproxyfen synthesis, in particular to a solvent-free method for preparing pyriproxyfen, which comprises the following steps: S1, mixing 2-chloropyridine and a sulfonic acid compound according to a molar ratio of 1: 1, and stirring at room temperature to obtain liquid 2-chloropyridine sulfonate ionic liquid; s2, mixing the 2-chloropyridine sulfonate ionic liquid with 1-(4-phenoxyphenyl)-2-propanol, heating to 145-165 DEG C, stirring, reducing the temperature to 30-35 DEG C, adding deionized water into the system, and separating a water layer to obtain a pyriproxyfen mixed solution; s3, deionized water with the same mass is added into the pyriproxyfen mixed solution, the temperature is reduced to 0-5 DEG C, suction filtration is conducted, and white crystal powder pyriproxyfen with the content being 98% or above is obtained. The purity of the pyriproxyfen prepared by the method is more than 98.5%, the yield is about 95%, addition of inorganic base is not needed, use of volatile organic solvents is not involved in the reaction process, and the pyriproxyfen is more environment-friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of pyriproxyfen synthesis, and particularly to a method for preparing pyriproxyfen without solvent. Background Art

[0002] Pyriproxyfen, also known as pyriproxifen, has the chemical name of 4-phenoxyphenoxy-(RS)-2-(2-pyridyloxy)-propyl ether. Pyriproxyfen is an insect growth regulator with juvenile hormone activity and was developed by Nihon Nohyaku Co., Ltd. in Japan. It has good control effects on agricultural pests such as Homoptera, Thysanoptera, Diptera, and Lepidoptera.

[0003] At present, the synthesis process of pyriproxyfen includes: First, phenol and p-chlorophenol are used to prepare p-phenoxyphenol through an ether synthesis reaction; then, under alkaline conditions, p-phenoxyphenol reacts with propylene oxide to obtain 1-(4-phenoxyphenoxy)-2-propanol; finally, 1-(4-phenoxyphenoxy)-2-propanol and 2-chloropyridine are subjected to an etherification reaction under alkaline conditions to obtain pyriproxyfen. It is represented by the following equations: ; Among them, the effect of the last step will directly determine the yield and quality of pyriproxyfen.

[0004] He Xihui et al. [Journal of Xihua University, 2007, 26(4): 34-37] reported that 1-(4-phenoxyphenoxy)-2-propanol, potassium hydroxide, and 2-chloropyridine were mixed without adding an additional solvent as the reaction medium, and the crude reaction product was recrystallized with anhydrous methanol to obtain white crystal pyriproxyfen with a yield of 86%.

[0005] Wang Qiang [Master's Thesis of Qingdao University of Science and Technology, 2012] used n(2-sodium pyridolate):n(1-(4-phenoxyphenoxy)-2-propyl p-toluenesulfonate)=1.6:1, toluene as the solvent, and a catalytic amount of DMF, and carried out a reflux reaction for 3 h. The yield of pyriproxyfen in this step was 91.0% and the purity was 91.3%.

[0006] Patents with the patent numbers [CN1267422C, CN1651414A] disclosed a two-step method for synthesizing pyriproxyfen and a purification method. With different organic solvents used, the crude product content was only about 85%, and it could reach more than 98.5% after recrystallization, but the recrystallization operation resulted in a true yield of pyriproxyfen of 46.5-72%.

[0007]

CN1209018C

[0008] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a method for preparing pyriproxyfen without solvent.

[0009] To achieve the above purpose, the present invention provides the following technical solutions: A method for preparing pyriproxyfen without solvent, comprising the following steps: S1. Mix 2-chloropyridine and a sulfonic acid compound in a molar ratio of 1:1, and stir at room temperature to obtain a liquid 2-chloropyridine sulfonate ionic liquid; S2. Mix the 2-chloropyridine sulfonate ionic liquid with 1-(4-phenoxyphenyl)-2-propanol, heat up to 145-165 °C, stir, then cool the temperature to 30-35 °C, add deionized water to the system, and then separate the water layer to obtain a pyriproxyfen mixture; S3. Add an equal mass of deionized water to the pyriproxyfen mixture, cool the temperature to 0-5 °C, and filter by suction to obtain white crystalline powdery pyriproxyfen with a content of more than 98%; Among them, the above process can be represented by the following equation:

[0010] Among them, R is one of aryl groups with 6-18 carbons.

[0011] Preferably, in step S1, the stirring speed is 350-450 r / min, and the time is 22-24 h.

[0012] Preferably, in step S2, the stirring speed is 350-450 r / min, and the time is 3-5 h.

[0013] Preferably, in step S2, the molar ratio of 1-(4-phenoxyphenyl)-2-propanol to 2-chloropyridine in step S1 is 1:1.

[0014] Preferably, in steps S2 and S3, the mass of the added deionized water is equal to the mass of 1-(4-phenoxyphenyl)-2-propanol.

[0015] Preferably, a solvent is also added in step S1, and the mass of the solvent is 2-3 times the total mass after mixing 2-chloropyridine and the sulfonic acid compound.

[0016] Preferably, the solvent is one or more of 2-chloropyridine, ethanol, methanol, and water.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The purity of pyriproxyfen prepared by the present invention is above 98.5%, and the yield is about 95%. At the same time, due to the very high boiling point of the ionic liquid, the high reaction temperature causes the by-product hydrogen chloride to escape from the system in the form of gas, eliminating the need to add inorganic base, and the reaction process does not involve the use of volatile organic solvents, making it more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a process flow chart of a method for preparing pyriproxyfen without solvent according to the present invention; Figure 2 is an infrared spectrum detection chart of 2-chloropyridine benzenesulfonic acid ionic liquid obtained in Example 6 of the present invention; Figure 3 is an infrared spectrum detection chart of 2-chloropyridine dodecylbenzenesulfonic acid ionic liquid obtained in Example 2 of the present invention; Figure 4 is a hydrogen spectrum chart of pyriproxyfen obtained in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0020] Please refer to Figures 1-4 , the present invention provides a technical solution: Example 1 A method for preparing pyriproxyfen without solvent: S1. Mix 11.35 g (0.1 mol) of 2-chloropyridine with 17.22 g (0.1 mol) of p-toluenesulfonic acid, stir at 350 r / min at room temperature for 22 h to obtain 28.57 g of liquid 2-chloropyridine p-toluenesulfonic acid ionic liquid; S2. Mix the obtained 28.57 g of 2-chloropyridine p-toluenesulfonic acid ionic liquid with 24.4 g (0.1 mol) of 1-(4-phenoxyphenyl)-2-propanol, heat up to 165 °C, stir at 350 r / min for 3 h, then cool the temperature to 30 °C, add 24.4 g of deionized water to the system, and then separate the water layer to obtain a pyriproxyfen mixture; S3. Add 24.4 g of deionized water to the pyriproxyfen mixture, cool the temperature to 0 °C, and perform suction filtration to obtain 31.03 g of white crystalline powdery pyriproxyfen with a content of 98.5%, and the yield is 95.2%.

[0021] Example 2 A method for preparing pyriproxyfen without solvent: S1. Mix 11.35 g (0.1 mol) of 2-chloropyridine with 32.6 g (0.1 mol) of dodecylbenzenesulfonic acid, add 87.9 g of ethanol, stir at room temperature at 450 r / min for 24 h, and remove the ethanol to obtain 43.95 g of liquid 2-chloropyridine dodecylbenzenesulfonate ionic liquid; S2. Mix 43.95 g of 2-chloropyridine dodecylbenzenesulfonate ionic liquid with 24.4 g (0.1 mol) of 1-(4-phenoxyphenyl)-2-propanol, heat up to 155 °C, stir at 450 r / min for 5 h, then cool the temperature to 35 °C, add 24.4 g of deionized water to the system, and then separate the water layer to obtain a pyriproxyfen mixture; S3. Add 24.4 g of deionized water to the pyriproxyfen mixture, cool the temperature to 5 °C, and perform suction filtration to obtain 30.87 g of white crystalline powdery pyriproxyfen with a content of 98.7%, and the yield is 94.9%.

[0022] Example 3 A method for preparing pyriproxyfen without solvent: S1. Mix 11.35 g (0.1 mol) of 2-chloropyridine with 32.6 g (0.1 mol) of dodecylbenzenesulfonic acid, add 132 g of methanol, stir at room temperature at 400 r / min for 23 h, and remove the methanol to obtain 43.95 g of liquid 2-chloropyridine dodecylbenzenesulfonate ionic liquid; S2. Mix 43.95 g of 2-chloropyridine dodecylbenzenesulfonate ionic liquid with 24.4 g (0.1 mol) of 1-(4-phenoxyphenyl)-2-propanol, heat up to 165 °C, stir at 400 r / min for 4 h, then cool the temperature to 32 °C, add 24.4 g of deionized water to the system, and then separate the water layer to obtain a pyriproxyfen mixture; S3. Add 24.4 g of deionized water to the pyriproxyfen mixture, cool the temperature to 0 - 5 °C, and perform suction filtration to obtain 31.03 g of white crystalline powdery pyriproxyfen with a content of 98.4%, and the yield is 95.1%.

[0023] Example 4 A method for preparing pyriproxyfen without solvent: S1. Mix 113.5 g (1 mol) of 2-chloropyridine with 172.2 g (1 mol) of p-toluenesulfonic acid, add 880 g of deionized water, and stir at room temperature at 420 r / min for 23 h to obtain 285.7 g of liquid 2-chloropyridine p-toluenesulfonate ionic liquid; S2. Mix 285.7 g of 2-chloropyridine p-toluenesulfonate ionic liquid with 244 g (1 mol) of 1-(4-phenoxyphenyl)-2-propanol, heat up to 145 °C, stir at 420 r / min for 4.5 h, then cool the temperature to 34 °C, add 224 g of deionized water to the system, and then separate the water layer to obtain a pyriproxyfen mixture; S3. Add 224 g of deionized water to the pyriproxyfen mixture, cool the temperature to 0 - 5 °C, and perform suction filtration to obtain 310 g of white crystalline powder pyriproxyfen with a content of 98.8%, and the yield is 95.4%.

[0024] Example 5 A method for preparing pyriproxyfen without solvent: S1. Mix 11.35 g (0.1 mol) of 2-chloropyridine with 17.22 g (0.1 mol) of p-toluenesulfonic acid, stir at room temperature at 350 r / min for 22 h to remove excess 2-chloropyridine, then add 24.4 g (0.1 mol) of 1-(4-phenoxyphenyl)-2-propanol, heat up to 145 °C, stir at 350 r / min for 3 h, then cool the temperature to 30 °C, add 24.4 g of deionized water to the system, and then separate the water layer to obtain a pyriproxyfen mixture; S2. Add 24.4 g of deionized water to the pyriproxyfen mixture, cool the temperature to 0 °C, and perform suction filtration to obtain 30.9 g of white crystalline powder pyriproxyfen with a content of 98.6%, and the yield is 94.9%.

[0025] Example 5 combines steps S1 and S2 into one step compared with Example 1, providing a new idea. The preparation steps of this process can be represented by the following equation: .

[0026] Example 6 A method for preparing pyriproxyfen without solvent: S1. Mix 11.35 g (0.1 mol) of 2-chloropyridine with 15.82 g (0.1 mol) of benzenesulfonic acid, stir at room temperature at 420 r / min for 23 h to obtain 27.17 g of liquid 2-chloropyridine benzenesulfonate ionic liquid; S2. Mix 27.17 g of 2-chloropyridinebenzenesulfonic acid ionic liquid with 24.4 g (0.1 mol) of 1-(4-phenoxyphenyl)-2-propanol, heat up to 165 °C, stir at 420 r / min for 4.5 h, then cool the temperature to 34 °C, add 22.4 g of deionized water to the system, and then separate the aqueous layer to obtain a pyriproxyfen mixture; S3. Add 22.4 g of deionized water to the pyriproxyfen mixture, cool the temperature to 0 - 5 °C, and perform suction filtration to obtain 31 g of white crystalline powdery pyriproxyfen with a content of 98.4% and a yield of 95.0%.

[0027] Comparative Example 1 The pyriproxyfen obtained by referring to the preparation method of pyriproxyfen in "CN107474012A" was subjected to performance testing. The obtained pyriproxyfen product had a content of 97.1% and a yield of 85.3%.

[0028] Result analysis: The pyriproxyfen obtained in Example 1 of the present invention was subjected to elemental analysis, and the obtained data are shown in Table 1 below: Table 1

[0029] The pyriproxyfen prepared by the preparation method of pyriproxyfen with the patent number "CN107474012A" in Comparative Example 1 was compared with Examples 1 - 6 of the present invention. Comparative Example 1 could not achieve the technical effects of the present invention in terms of purity and yield.

[0030] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing pyriproxyfen without solvent, characterized in that, It includes the following steps: S1. Mix 2-chloropyridine and a sulfonic acid compound in a molar ratio of 1:1, and stir at room temperature to obtain a liquid 2-chloropyridine sulfonate ionic liquid; S2. Mix the 2-chloropyridine sulfonate ionic liquid with 1-(4-phenoxyphenyl)-2-propanol, heat up to 145-165 °C, stir, then cool the temperature to 30-35 °C, add deionized water to the system, and then separate the water layer to obtain a pyriproxyfen mixture; S3. Add an equal mass of deionized water to the pyriproxyfen mixture, cool the temperature to 0-5 °C, and filter by suction to obtain white crystalline powdery pyriproxyfen with a content of over 98%; Among them, the above process can be represented by the following equation: ； Among them, R is one of aryl groups with 6-18 carbons.

2. The method for preparing pyriproxyfen without solvent according to claim 1, wherein In step S1, the stirring speed is 350-450 r / min, and the time is 22-24 h.

3. A method for preparing pyriproxyfen without solvent according to claim 1, characterized in that, In step S2, the stirring speed is 350-450 r / min, and the time is 3-5 h.

4. A method for preparing pyriproxyfen without solvent according to claim 1, characterized in that, In step S2, the molar ratio of 1-(4-phenoxyphenyl)-2-propanol to 2-chloropyridine in step S1 is 1:

1.

5. A method for preparing pyriproxyfen without solvent according to claim 1, characterized in that, The mass of the deionized water added in steps S2 and S3 is equal to the mass of 1-(4-phenoxyphenyl)-2-propanol.

6. A method for preparing pyriproxyfen without solvent according to claim 1, characterized in that, A solvent is also added in step S1, and the mass of the solvent is 2-3 times the total mass after mixing 2-chloropyridine and the sulfonic acid compound.

7. A method for preparing pyriproxyfen without solvent according to claim 6, characterized in that, The solvent is one or more of 2-chloropyridine, ethanol, methanol, and water.

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