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Production method of 2,3-dichloropyridine

A production method, the technology of dichloropyridine, which is applied in two fields, can solve problems such as reducing work efficiency, unstable product quality, affecting yield and the environment, and achieves the effect of ensuring quality

Active Publication Date: 2011-06-08
南京广通医药化工有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention provides a kind of production method of 2,3-dichloropyridine, has solved the difficult problem in the prior art: namely 2 chlorination reaction very easily produces by-product, causes final product quality not stable enough, if carry out intermediate purification and Affects yield and environment and reduces work efficiency

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Add 39.1 g (0.25 mol) of 2-chloronicotinamide and 160 ml of water into a 1000 ml reaction bottle, stir and dissolve at room temperature. The temperature was lowered in an ice-salt bath, and 223.5 g of 10% sodium hypochlorite was added dropwise at 1° C., and the process control temperature was 0° C. to 5° C. for 2 hours. When the addition was completed, the temperature was 4°C, and then 80 g of 30% sodium hydroxide solution was added dropwise for 1.5 hours, and the temperature was controlled at 0°C to 5°C during the process. When the addition was completed, the temperature was 3°C, and the temperature was changed to a water bath to slowly raise the temperature, and it reached 80°C after 45 minutes, and then kept at 80-85°C for 2 hours. Cool down, stir slowly for 5 hours at 5°C, filter with suction and dry. 27.95 g of off-white solid 2-chloro-3-aminopyridine was obtained (87% yield).

[0023] Add the above-mentioned intermediate product into a 1000ml reaction flask, add...

Embodiment 2

[0026] Add 39.1 g (0.25 mol) of 2-chloronicotinamide and 190 ml of water into a 1000 ml reaction bottle, and stir to dissolve at room temperature. The temperature was lowered in an ice-salt bath, and 223.5 g of 10% sodium hypochlorite was started to be added dropwise at 0° C., and the process control temperature was 0° C. to 5° C., which took 2.5 hours. When the addition was completed, the temperature was 2°C, and then 100 g of 30% sodium hydroxide solution was added dropwise for 1.5 hours, and the temperature was controlled at 0°C to 5°C during the process. When the addition was completed, the temperature was 5°C, and the temperature was changed to a water bath to slowly raise the temperature, and it reached 80°C after 50 minutes, and then kept at 80-85°C for 2 hours. Cool down, stir overnight at a slow speed at 4°C, filter with suction and dry. 28.35 g of off-white solid 2-chloro-3-aminopyridine was obtained (yield 88.2%).

[0027] Add the above-mentioned intermediate prod...

Embodiment 3

[0030] Add 39.1Kg (0.25kmol) of 2-chloronicotinamide and 190l of water into a 1000L reactor, and stir to dissolve at room temperature. The temperature was lowered in an ice-salt bath, and 223.5 kg of 10% sodium hypochlorite was added dropwise at 0° C., and the process control temperature was 0° C. to 5° C., which took 132 minutes. When the addition is completed, the temperature is 3°C, and then 100Kg of 30% sodium hydroxide solution is added dropwise for 91 minutes, and the temperature is controlled at 0°C to 5°C during the process. At the end of the addition, the temperature was 4°C, and the jacketed steam was used to raise the temperature slowly, and it reached 80°C after 54 minutes, and then kept at 80-85°C for 2 hours. The jacket was changed to water to cool down to near normal temperature, and then iced brine was used to continue cooling down, stirring to maintain the temperature at 0°C to 5°C for several hours, suction filtration, and drying. 28.74Kg of off-white solid ...

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Abstract

The invention relates to a production method of 2,3-dichloropyridine, solving the problem that byproducts are easily generated through 2-position chlorination reaction so as to cause the final product quality to be instable, for example, intermediate purification is carried out but yield and environment are influenced, and the working efficiency is reduced. The production method of the 2,3-dichloropyridine comprises the following steps: 1) carrying out degradation reaction: hydrolyzing 2-chloro nicotinamide used as a starting material, and carrying out solid-liquid separation to obtain 2-chlorine-3-aminopyridine; and (2) successively carrying out diazotization reaction and 3-position chlorination reaction: successively carrying out diazotization reaction and 3-position chlorination reaction on 2-chlorine-3-aminopyridine to obtain 2,3-dichloropyridine. The production method has the beneficial effects that (1) the difficulty that the byproducts are easily generated because 2-position chlorination is successfully avoided, thereby ensuring the quality of the intermediate product 2-chlorine-3-aminopyridine; and (2) because the intermediate product 2-chlorine-3-aminopyridine is not dissolved in strong basic aqueous solution, the product can be directly taken out by vacuum filtration, and is easy to purify.

Description

technical field [0001] The invention relates to a production method of 2,3-dichloropyridine. Background technique [0002] 2,3-Dichloropyridine is an important fine chemical intermediate, which is widely used in the fields of medicine and pesticides, especially with the listing of o-formamidobenzamide insecticides, this product as a key intermediate Synthesis technology has become a research hotspot. But its representative literature has only two patents: [0003] First, the PCT international application WO2005070888 published by DuPont of the United States on August 4, 2005; its basic features are: using nicotinamide as the starting material, degrading, concentrating and dehydrating, and washing the residue with hydrochloric acid to obtain 3-aminopyridine After adding dry hydrogen chloride gas to increase the acid concentration, control the temperature and add hydrogen peroxide dropwise to carry out 2-position chlorination reaction, then adjust different pH values, and wa...

Claims

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Application Information

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IPC IPC(8): C07D213/61
Inventor 赵超赵桃林
Owner 南京广通医药化工有限责任公司
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