Method for synthesizing 2, 3, 5-trichloropyridine

A technology of trichloropyridine and a synthesis method, applied in the field of pesticide chemical industry, can solve the problems of complicated synthesis process operation, unsatisfactory product yield, harsh reaction conditions, etc., and achieves the effects of high product yield, less three wastes and thorough reaction.

Active Publication Date: 2018-11-30
JIANGSU FUDING CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The synthesis process is relatively cumbersome to operate, the reaction conditions are relatively harsh, it is not easy to control, and it n

Method used

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  • Method for synthesizing 2, 3, 5-trichloropyridine

Examples

Experimental program
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Effect test

Example Embodiment

[0027] Example 1

[0028] Add 60g of methanol into a 1000mL four-necked flask, put in 100g of 2,3,5,6-tetrachloropyridine, 31.7g of hydrazine hydrate, raise the temperature to 60~65℃, keep the temperature for about 2 hours, the reaction is over, and the temperature is reduced to 0~5 Stir at ℃ for 1 hour, filter, and the solid is 2,3,5-trichlorohydrazinopyridine 6-hydrate, dried to obtain 101.6g of white solid, yield 96%, content 98.5%.

[0029] Add 100g of 2,3,5-trichlorohydrazinopyridine 6-hydrate to a 1000ml four-necked flask, 50g of 5% sodium hydroxide aqueous solution, raise the temperature to 70~75℃, drop 387.6g of 10% sodium hypochlorite aqueous solution, Incubate at 70~75℃, react for 1 hour, the reaction is over, cool to 5~10℃, stir for 1 hour, filter to obtain crude 2,3,5-trichloropyridine, and distill under reduced pressure to obtain the product as a light yellow solid. Rate: 95%, content: 98%.

Example Embodiment

[0030] Example 2

[0031] Add 50g of methanol into a 1000mL four-necked flask, put in 100g of 2,3,5,6-tetrachloropyridine, 34.6g of hydrazine hydrate, raise the temperature to 55~60℃, keep the temperature and react for about 2 hours, the reaction is over, and the temperature is reduced to 0~5 Stir for 1.5 hours at ℃, filter, the solid is 2,3,5-trichlorohydrazinopyridine 6-hydrate, and dry to obtain 101.5g of white solid with 95.8% yield and 98.5% content.

[0032] Add 100g of 2,3,5-trichlorohydrazinopyridine 6-hydrate to a 1000ml four-neck bottle, 45g of 5% sodium hydroxide aqueous solution, heat to 70~75℃, drop 355.3g of 10% sodium hypochlorite aqueous solution, Incubate at 70~75℃, react for 1 hour, the reaction is over, cool to 5~10℃, stir for 1 hour, filter to obtain crude 2,3,5-trichloropyridine, and distill under reduced pressure to obtain the product as a light yellow solid. Rate: 93%, content: 98%.

Example Embodiment

[0033] Example 3

[0034] Add 60g of methanol into a 1000mL four-necked flask, put in 100g of 2,3,5,6-tetrachloropyridine, 33.1g of hydrazine hydrate, raise the temperature to 60~65℃, keep the temperature for about 2 hours, the reaction is over, and the temperature is reduced to 0~5 Stir for 1 hour at ℃, filter, and the solid is 2,3,5-trichlorohydrazinopyridine 6-hydrate, and dried to obtain 101.6g of white solid with a yield of 96% and a content of 98.4%.

[0035] Add 100g of 2,3,5-trichlorohydrazinopyridine 6-hydrazine, 57g of 5% sodium hydroxide aqueous solution to a 1000ml four-necked flask, heat up to 70~75℃, dropwise add 360g of 10% sodium hypochlorite aqueous solution, keep warm 70~75℃, react for 1 hour, the reaction is over, cool to 5~10℃, stir for 1 hour, filter to obtain crude 2,3,5-trichloropyridine, and distill under reduced pressure to obtain the product as a pale yellow solid. Yield : 94.5%, content: 98%.

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Abstract

The invention discloses a method for synthesizing 2, 3, 5-trichloropyridine. The method mainly comprises: (1) synthesis of 2, 3, 5-trichloro-6-hydrated hydrazinyl pyridine: adding hydrazine hydrate and a reaction solvent into 2, 3, 5, 6-tetrachloropyridine as a raw material, carrying out a reaction process at a certain temperature for some time and carrying out treatment to obtain 2, 3, 5-trichloro-6-hydrated hydrazinyl pyridine, and (2) reaction of 2, 3, 5-trichloro-6-hydrated hydrazinyl pyridine and a sodium hypochlorite aqueous solution in an alkaline environment at a certain temperature for a certain period of time, then treatment and reduced pressure distillation. The method has the advantages of low reaction raw material price, no high toxic, no irritation, small three waste amount,environmentally friendly processes, relatively thorough reaction, simple process control and high product yield.

Description

technical field [0001] The invention belongs to the field of pesticide chemical industry, and in particular relates to a synthesis method of 2,3,5-trichloropyridine. Background technique [0002] 2,3,5-Trichloropyridine is an important fine chemical intermediate, widely used in the fields of medicine and pesticide research. 2,3,5-Trichloropyridine reacts with alkali metal hydroxide to prepare 3,5-dichloro-2-pyridinol, which is an important raw material for synthesizing a series of pesticides such as insecticidal mite and herbicide oxafluben. 2,3,5-trichloropyridine can also be further fluorinated to synthesize 2,3-difluoro-5-chloropyridine, which is the basic raw material for the synthesis of the herbicide clodinafop-propargyl. [0003] At present, there are not many reports on the synthesis method of 2,3,5-trichloropyridine, mainly as follows: (1) Patent WO0155-11 discloses that pentachloropyridine is used as a raw material, and dechlorination is carried out in the presenc...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 常青董海龙张胜山
Owner JIANGSU FUDING CHEM
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