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Method for preparing 2-chloro-5-chloromethylpyridine

A technology of chloromethylpyridine and trichloromethylpyridine, which is applied in the field of preparation of 2-chloro-5-chloromethylpyridine, can solve the problems of poor selectivity of chlorination reaction and low yield of target product, and realize recycling , The synthesis method is green and environmentally friendly, and the process control is simple

Active Publication Date: 2019-12-17
XIAN CATALYST NEW MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the method for synthesizing 2-chloro-5-picoline with 3-picoline or 2-chloro-5-picoline in existing reports generates a large amount of useless by-product 2-chloro-5-trichloromethyl Pyridine, there are problems such as poor selectivity of chlorination reaction and low yield of target product

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  • Method for preparing 2-chloro-5-chloromethylpyridine

Examples

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Effect test

Embodiment 1

[0035] The method for preparing 2-chloro-5-chloromethylpyridine in this example uses 2-chloro-5-trichloromethylpyridine as a raw material for selective hydrogenation dechlorination reaction to obtain 2-chloro-5-chloromethylpyridine pyridine;

[0036] The catalyst of the selective hydrodechlorination reaction is Pd / C catalysis, and the Pd / C catalyst includes carrier activated carbon and noble metal palladium loaded on the carrier activated carbon, and the mass percentage of noble metal Pd in ​​the Pd / C catalyst is 3%;

[0037] The acid-binding agent of the selective hydrodechlorination reaction is sodium phosphate;

[0038] The organic solvent of the selective hydrodechlorination reaction is methyl acetate;

[0039] The preparation method comprises the following steps:

[0040] Step 1, dissolving sodium phosphate in water to obtain an aqueous sodium phosphate solution with a mass content of 30%, 1300g methyl acetate is placed in an autoclave, and 1000g2-chloro-5-trichloromet...

Embodiment 2

[0051] This embodiment is the same as embodiment 1, wherein the difference is that the acid-binding agent of the selective hydrodechlorination reaction is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, triethanolamine, 2 -Hydroxyethylamine or ammonia gas.

[0052] In this example, the yield of 2-chloro-5-chloromethylpyridine is 87.1%-87.3%, and the gas chromatography purity of 2-chloro-5-chloromethylpyridine is 98.4%-98.5%. In this embodiment, the recycled catalyst was recycled 5 times, and the yield and purity of 2-chloro-5-chloromethylpyridine remained basically unchanged during the recycled process.

Embodiment 3

[0054] The method for preparing 2-chloro-5-chloromethylpyridine in this example uses 2-chloro-5-trichloromethylpyridine as a raw material for selective hydrogenation dechlorination reaction to obtain 2-chloro-5-chloromethylpyridine pyridine;

[0055] The catalyst of the selective hydrodechlorination reaction is Pd / C catalysis, and the Pd / C catalyst includes carrier activated carbon and noble metal palladium loaded on the carrier activated carbon, and the mass percentage of noble metal Pd in ​​the Pd / C catalyst is 10%;

[0056] The acid-binding agent of the selective hydrodechlorination reaction is triethanolamine;

[0057] The organic solvent of the selective hydrodechlorination reaction is ethyl acetate;

[0058] The preparation method comprises the following steps:

[0059] Step 1, 2500g ethyl acetate is placed in autoclave, drop into 1000g2-chloro-5-trichloromethylpyridine, 1gPd / C catalyst, 552g triethanolamine and 400g pure water in described autoclave, first use Nitro...

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Abstract

The invention discloses a method for preparing 2-chloro-5-chloromethylpyridine, and the method comprises the following steps: performing selective hydrogenation dechlorination reaction on 2-chloro-5-trichloromethylpyridine serving as a raw material to prepare the 2-chloro-5-chloromethylpyridine; wherein a catalyst is a noble metal catalyst taking activated carbon or aluminum oxide as a carrier, and the mass percentage of a noble metal in the noble metal catalyst is 1%-10%; wherein the mass of the noble metal catalyst is 0.1%-0.5% of the mass of the 2-chloro-5-trichloromethylpyridine; an acid-binding agent is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, triethylamine, triethanolamine, 2-hydroxyethylamine or ammonia gas; and an organic solvent is toluene, xylene, methyl acetate, ethyl acetate or 2-methyltetrahydrofuran. The yield of the 2-chloro-5-chloromethylpyridine exceeds 82%, the purity of the 2-chloro-5-chloromethylpyridine is 98%or above, the process control is simple, less industrial ''three wastes' 'are generated, and the synthesis method is green and environmentally friendly.

Description

technical field [0001] The invention belongs to the technical field of pesticide intermediate synthesis, and in particular relates to a method for preparing 2-chloro-5-chloromethylpyridine. Background technique [0002] 2-Chloro-5-chloromethylpyridine is an important fine chemical raw material, widely used in the synthesis of pyridine series insecticides, such as imidacloprid, thiacloprid, acetamiprid, nitenpyram, etc. There are many synthetic methods of 2-chloro-5-chloromethylpyridine currently disclosed, mainly including directional ring method and chlorination synthesis method, wherein the directional ring method mainly includes 2-chloro-5-aminomethylpyridine diazonium-chlorination method, morpholine-propionaldehyde method, cyclopentadiene-acrolein method, benzylamine-propionaldehyde method, 2-picoline-oleum reduction method, 2-chloro-2-chloromethyl 4-cyano Butyraldehyde cyclization method. Although the directional ring method has the advantages of high product quality,...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 高武李小安姚琪韩彬校大伟张宇
Owner XIAN CATALYST NEW MATERIALS CO LTD
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