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A kind of preparation method of 2,3-dichloropyridine

A technology of dichloropyridine and aminopyridine, which is applied in the field of preparation of 2,3-dichloropyridine, can solve the problems of complex reaction principle, many side reactions, and difficult yield, and shorten the preparation process, reduce waste liquid, The effect of reducing production costs

Active Publication Date: 2015-11-18
NANTONG TENDENCI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0017] The reaction principle of this method is complicated, and there are many side reactions, so it is difficult to obtain a higher product yield.

Method used

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  • A kind of preparation method of 2,3-dichloropyridine
  • A kind of preparation method of 2,3-dichloropyridine
  • A kind of preparation method of 2,3-dichloropyridine

Examples

Experimental program
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Effect test

Embodiment 1

[0036] Preparation of 3-aminopyridine: Add 150 ml of water into a 1000 ml four-necked round bottom flask equipped with a stirring and thermometer, add 36.6 g (0.3 mol) of nicotinamide under stirring, and cool down to 0-5°C after completely dissolving , and then 272 g (0.33 mol) of 9.05% sodium hypochlorite solution was added dropwise in the range of 0-5°C during 30-60 minutes, and stirred for 30 minutes after the dropwise addition was completed. At the same temperature, 48 grams (0.6 mol) of 50% liquid caustic soda was added dropwise, and the reaction was stirred for 30 minutes.

[0037] In another 1000 ml four-necked round bottom flask equipped with stirring, thermometer and condenser tube, add 240 ml of water, heat up to 90-100°C, and add dropwise at 0 during this temperature range and 30-45 minutes The above reaction solution stored at -5°C was continued for 2 hours after the dropwise addition. After the reaction, the weight of the reaction solution was 747 grams. The conte...

Embodiment 2

[0044] Embodiment 2: the preparation of 3-aminopyridine

[0045] Method 1: Add 300 ml of water into a 1000 ml four-necked round bottom flask equipped with stirring, thermometer and condenser tube, add 73.3 g (0.6 mol) of accurately measured nicotinamide under stirring, and cool down to 0- At 5°C, 26.7 g (0.2 mol) of 30% liquid caustic soda was added dropwise. Then control the temperature of the material within the range of 0-5°C, add dropwise 545 g (0.66 mol) of 9.05% sodium hypochlorite solution, and stir for 30 minutes after the dropwise addition. Within the same temperature index, the dropwise concentration is 213 grams (1.6mol) of 30% liquid caustic soda, and the material is controlled within 0-8°C after the dropwise addition is completed. Stir for 30 minutes to raise the temperature, raise the temperature to 70-80°C, and keep it warm for 2 hours. After the reaction, weigh the weight of the reaction solution (1184 grams), analyze the content of 3-aminopyridine with liquid...

Embodiment 3

[0049] Preparation of 2-chloro-3-aminopyridine: Add 360 grams of industrial hydrochloric acid (content: 30.5%, 3mol), 0.3mol (28.2 grams) of 3-aminopyridine into a 1000ml four-neck round-bottomed flask equipped with stirring and a thermometer. Pyridine, stir to dissolve, add 27% hydrogen peroxide 45.4g (0.36mol) dropwise at 10-15°C, dropwise for 1.5-2 hours, keep warm at 10-15°C for reaction, after 3.5 hours of reaction, the reaction is over, add 10g of sub Sodium bisulfate until the starch potassium iodide test paper does not show blue, using liquid chromatography, external standard method analysis, the molar yield of 2-chloro-3-aminopyridine is 86.5% (based on 3-aminopyridine).

[0050] The following preparation method is the same as in Example 1. In this example, the content of 2,3-dichloropyridine: 98.8%, and the molar yield: 69.5%.

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Abstract

The invention discloses a preparation method for 2,3-dichloropyridine. The preparation method creatively comprises the steps of reacting nicotinamide serving as an active ingredient with sodium hypochloride to prepare 3-aminopyridine, distilling to remove water, extracting with dichloromethane to recover 3-aminopyridine, wherein the yield of the 3-aminopyridine is more than or equal to 93%; reacting the 3-aminopyridine hydrochloric acid solution with hydrogen peroxide to obtain 2-chlorino-3-aminopyridine hydrochloric acid solution, wherein the yield of the 2-chlorino-3-aminopyridine is more than or equal to 85%; then performing diazotization and sandmeyer reaction to obtain 2,3-dichloropyridine. The preparation method is less in side reaction, an intermediate product is not required for refining, and the product is high in content and yield, simple in technology and easy to operate.

Description

technical field [0001] The invention relates to a preparation method of 2,3-dichloropyridine, in particular to a preparation method of 2,3-dichloropyridine with improved product content and yield. Background technique [0002] 2,3-Dichloropyridine is a chloropyridine with the widest application and the largest dosage among the 6 dichloropyridine isomers. It is an important fine chemical intermediate and is widely used in the fields of medicine and pesticides. It is a key intermediate of the new insecticide chlorantraniliprole. At present, the preparation method of 2,3-dichloropyridine mainly adopts nicotinamide and sodium hypochlorite to obtain 3-aminopyridine through Hofmann degradation reaction, and then obtains 2,3-dichloropyridine through oxychlorination reaction, diazotization and Sandmeyer reaction. The principle of the side reaction is as follows: [0003] Main response: [0004] [0005] [0006] [0007] [0008] side effects: [0009] [0010] ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 周甦谭建平奚一平
Owner NANTONG TENDENCI CHEM
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