Method for synthesizing imidacloprid employing cascade reaction

A technology of series reaction and imidacloprid is applied in the field of synthesis technology of insecticide imidacloprid, and can solve the problems of low purity affecting the quality of final product, many by-products, complicated steps and the like

Inactive Publication Date: 2015-06-03
JIAXING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process uses a highly toxic organic solvent, acetocyanide, and is synthesized in two steps. The steps are complicated and there are many by-products. The biggest problem of this process is that the purity of the first product 2° amine (secondary amine) is low and affects the quality of the final product.

Method used

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  • Method for synthesizing imidacloprid employing cascade reaction
  • Method for synthesizing imidacloprid employing cascade reaction
  • Method for synthesizing imidacloprid employing cascade reaction

Examples

Experimental program
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Effect test

Embodiment 1

[0025] Add 1.62g (10mmol) 2-chloro-5-chloromethylpyridine, 1.04g (10mmol) nitroguanidine, 5ml ethanol solvent and 0.5g boron tetrafluoride 1-methyl-3-butyl in a three-necked flask Imidazole ionic liquid was added dropwise with 0.3ml of 37% hydrochloric acid, heated, and 3.01g (50mmol) of anhydrous ethylenediamine was added at 45°C with stirring, the pH was 5-6, and the heating was stopped after 3 hours of reaction. Add 1.5 g of potassium carbonate solid to remove HCl, and filter to obtain a yellow clear liquid. The ethanol solvent and unreacted anhydrous ethylenediamine were evaporated to obtain a pale yellow solid, that is, crude imidacloprid. The crude imidacloprid was added to pure water and heated and stirred to near boiling, filtered while hot, the obtained crystals were washed 3 times with pure water, the precipitate was dried and crystallized in acetone, and finally the crystals were vacuum dried to obtain 2.35 g of light yellow crystals. The purity was 98% by liquid ch...

Embodiment 2

[0027] Add 1.62g (10mmol) 2-chloro-5-chloromethylpyridine, 1.04g (10mmol) nitroguanidine, 6ml ethanol and 0.2g monoethyl hydrogen sulfate N-ethylpyridine ionic liquid into a three-necked flask, 0.3ml of 37% hydrochloric acid was added dropwise, heated, and 3.01g (50mmol) of anhydrous ethylenediamine was added at 45°C with stirring, the pH was 6-7, and the heating was stopped after 3 hours of reaction. Add 2 grams of potassium carbonate solid to remove HCl, and filter to obtain a yellow clear liquid. The ethanol solvent and unreacted anhydrous ethylenediamine were evaporated to obtain a pale yellow solid, that is, crude imidacloprid. The crude imidacloprid was added to pure water and heated and stirred to near boiling, filtered while hot, the obtained crystals were washed 3 times with pure water, the precipitate was dried and crystallized in acetone, and finally the crystals were vacuum dried to obtain 2.42 g of light yellow crystals. The purity was 96% by liquid chromatography...

Embodiment 3

[0029] Add 1.62g (10mmol) 2-chloro-5-chloromethylpyridine, 1.04g (10mmol) nitroguanidine, 6ml ethanol solvent and 0.2g monoethyl hydrogen sulfate N-ethylpyridine ionic liquid into a three-necked flask , And add dropwise 0.5ml of 37% hydrochloric acid, heat, add 3.01g (50mmol) of anhydrous ethylenediamine at 50°C under stirring, pH value is 4 to 5, after 3 hours of reaction, stop heating. Add 2 grams of potassium carbonate solid to remove HCl, and filter to obtain a yellow clear liquid. The ethanol solvent and unreacted anhydrous ethylenediamine were evaporated to obtain a pale yellow solid, that is, crude imidacloprid. The crude imidacloprid was added to pure water and heated and stirred to near boiling, filtered while hot, the obtained crystals were washed 3 times with pure water, the precipitate was dried and crystallized in acetone, and finally the crystals were dried under vacuum to obtain 2.52 g of light yellow crystals. The purity was 97% by liquid chromatography and the...

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Abstract

The invention discloses a method for synthesizing imidacloprid employing cascade reaction. The method comprises the following steps: with 2-chlorine-5-chloromethyl pyridine, ethidene diamine and guanidine nitrate as raw materials, mixing 2-chlorine-5-chloromethyl pyridine, ethidene diamine and guanidine nitrate with a certain amount of solvent ethanol; adding a little of ionic liquid as a catalyst, controlling the pH value of the reaction process to be about 6 with a little of hydrochloric acid; heating, warming, and slowly dropwise adding a certain amount of ethidene diamine, reacting, heating for a certain period of time, stopping heating, and cooling to a room temperature; and purifying and drying to obtain an imidacloprid product. Due to adoption of one-pot cascade reaction, an intermediate product 2-degree amine is high in activity, and easily forms a heterocyclic ring together with nitroguanidine; byproducts can be prevented; and the high-purity imidacloprid is synthesized. Compared with an original two-step technology, the method for preparing the imidacloprid disclosed by the invention is simple in reaction step; the yield and the purity of the product are greatly improved; the yield reaches more than or equal to 95%; the purity of a reaction product through gas chromatography reaches more than or equal to 90%.

Description

Technical field [0001] The invention relates to a synthesis process of the insecticide imidacloprid, and a method for synthesizing imidacloprid by a series reaction. Background technique [0002] The scientific name of imidacloprid is 1-(6-chloropyridin-3-pyridylmethyl)-N-nitroimidazolidine. It is a high-efficiency, low-toxicity, and low environmental pollution pesticide. It is widely used in rice, For the prevention and control of diseases and insect pests in potato, cotton, corn, sugar beet and other crops, it can be mixed with certain pesticides to achieve the purpose of controlling multiple diseases and insect pests at one time, which has considerable application value. The traditional nitroguanidine method to synthesize imidacloprid is a two-step method, using 2-chloro-5-chloromethylpyridine, ethylenediamine and guanidine nitrate as raw materials, the first step is from 2-chloro-5-chloromethylpyridine and ethyl The nucleophilic substitution of the diamine in the organic sol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D401/06
CPCC07D401/06
Inventor 吴建一缪程平张洋屠晓华宗乾收吴宁浩章瑛
Owner JIAXING UNIV
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