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Synthesis method of quizalofop-p-ethyl

A technology of quizalofop-p-p and dichloroquinoxaline, which is applied in the field of synthesis of the herbicide quizalofop-p-p-p-p in rice fields, can solve problems such as low efficiency, low optical purity, and large pollution, so as to increase reaction yield and improve optical efficiency. Purity and the effect of shortening the reaction time

Pending Publication Date: 2022-05-13
HAIZHENG CHEM NANTONG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] In summary, in order to solve the problems of low efficiency, low optical purity, and large pollution in the prior art, it is urgent to develop a preparation of quizalofop-p-ethyl with high efficiency, high optical purity, environmental friendliness, and industrialized production. method to meet the growing demand for industrial production

Method used

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  • Synthesis method of quizalofop-p-ethyl
  • Synthesis method of quizalofop-p-ethyl
  • Synthesis method of quizalofop-p-ethyl

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041]199.0KG (1.0kmol) 2,6-dichloroquinoxaline, 210.2KG (1.0kmol, optical purity 99.9%) R (+) 2-(4-hydroxyphenoxy) ethyl propionate, 207.3KG (1.5 kmol) potassium carbonate, 32.2KG (0.1kmol) catalyst tetrabutylammonium bromide, 460.0KG toluene into the reactor, stirring at room temperature, heating up to 70-80 ° C for about 3-4 hours, while reacting at -0.07MPa Under the pressure of ~-0.08MPa, depressurize and reflux to separate water, and then react with nitrogen gas at the bottom of the kettle for about 3-4 hours, and take samples for inspection until the content of 2,6-dichloroquinoxaline is ≤0.5%, and the reaction is terminated.

[0042] After the reaction is finished, cool down to 40-50°C within 30 minutes, wash the reaction solution with water several times until the water layer is absolutely neutral, separate layers, decolorize and dissolve the organic layer, crystallize with absolute ethanol, filter, and dry to obtain 364.4KG product.

[0043] The total reaction time ...

Embodiment 2

[0044] Embodiment 2: Except that the reaction temperature is replaced by 65-70° C., all the others are the same as in Embodiment 1, and 361.0 KG of the product are obtained.

[0045] The total reaction time of this example is about 8-10 hours, the chemical content of quizalofop-p-ethyl is 97.7%, the yield is 94.61%, and the optical purity is >99%.

Embodiment 3

[0046] Embodiment 3: Except that the reaction temperature is replaced by 80-85° C., all the others are the same as in Embodiment 1, and 362.2 KG of the product are obtained.

[0047] The total reaction time of this example is about 5-6 hours, the chemical content of quizalofop-p-ethyl is 97.6%, the yield is 94.82%, and the optical purity is >99%.

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Abstract

The invention relates to a preparation method of quizalofop-p-ethyl, which comprises the following steps: reacting 2, 6-dichloroquinoxaline (II) with R (+) 2-(4-hydroxyphenoxy) ethyl propionate (III) in the presence of an organic solvent, an acid-binding agent and a catalyst until the 2, 6-dichloroquinoxaline is less than or equal to 0.5%, and ending the reaction to obtain the quizalofop-p-ethyl (I) with high optical content, the catalyst is selected from one or a mixture of more of tetrabutylammonium bromide, benzyltriethylammonium chloride and N, N-dimethylformamide. According to the method disclosed by the invention, the specific catalyst is added, and the highest reaction temperature is adjusted to 85 DEG C or below, so that the reaction time is greatly shortened, and the racemization problem caused by long-time reaction of quizalofop-p-ethyl in a high-temperature and strong-alkali environment is avoided; meanwhile, water is separated through reduced pressure reflux while reacting, water generated in the reaction is removed in time, product hydrolysis is avoided, the reaction rate and yield are increased, and the method has high industrialization value.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis of pesticide products, in particular to a method for synthesizing quizalofop-p-ethyl, a herbicide for paddy fields. Background technique [0002] Quizalofop-p-ethyl, also known as Jinghe grass gram, English common name: Quizalofop-p-ethyl, chemical name: (R)-2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy] Ethyl propionate, English name: (2R)-2-{4-[(6-chloroquinoxalin-2-yl)oxy]phenoxy}propanoic acid, is a phenoxycarboxylic acid herbicide developed by Nissan Chemical Industry Company of Japan. The pure product is white powdery crystal, with a melting point of 76-77°C and a solubility in water of 0.0003g / L (20°C). [0003] Quizalofop-ethyl is mainly used to control annual and perennial grass weeds in broad-leaved crops, such as barnyardgrass, foxtail, wild oats, brome, and stephae, and is ineffective against broad-leaved weeds. The product is a selective systemic conduction herbicide for stem ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D241/44
CPCC07D241/44
Inventor 徐坚勇唐子英包如胜蒋富国金晓东
Owner HAIZHENG CHEM NANTONG CO LTD
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