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Method for preparing 2-chloro-5-picoline

A technology of picoline and pyridone, which is applied in the field of chlorination to prepare 2-chloro-5-picoline, can solve the problems of side reactions, low selectivity and instability in the chlorination process, and achieve the effect of improving reaction efficiency

Inactive Publication Date: 2019-05-31
JIANGSU YANGNONG CHEM GROUP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reaction is an exothermic reaction, and it is difficult to quickly remove the heat of reaction in a batch process, which is prone to side reactions
The pyridone chloride adduct is an intermediate, which is unstable and easy to deteriorate, resulting in low selectivity in the chlorination process

Method used

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  • Method for preparing 2-chloro-5-picoline
  • Method for preparing 2-chloro-5-picoline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Raw material preparation: Weigh 1000g of pyridone with a content of 95%, put it into a four-necked bottle containing 1000g of chlorobenzene, stir to make it completely dissolve and set aside.

[0019] Synthesis of pyridinol: The reaction process adopts a continuous flow microchannel reactor, and feeds at the same time according to the ratio of 30% pyridone chlorobenzene liquid and chlorine gas substance of 1:1.05 as the raw material. The temperature of the first three plates is 50 ° C, and the temperature of the last three plates is 160 ° C. ℃, on the 4th plate pump into the quality of pyridone and other sodium carbonate aqueous solution (sodium carbonate content 10%). Controlling the residence time of reaction material by the flow rate of pump is 90s, and pyridinol chlorobenzene liquid discharges and collects continuously, adds DMF (accounting for 12% of pyridine weight) wherein to be used for next step reaction.

[0020] The synthesis of 2-chloro-5-picoline: the react...

Embodiment 2

[0022] (batch synthesis process)

[0023] Raw material preparation: Weigh 1000g of pyridone with a content of 95%, put it into a four-necked bottle containing 1000g of chlorobenzene, stir to make it completely dissolve and set aside.

[0024] Synthesis of pyridinol: put 225.2g of pyridone chlorobenzene solution (about 0.5mol of pyridone) into a 500mL four-necked bottle equipped with a thermometer and stirring, cool down to about 20°C and start to introduce chlorine gas, the flow rate of chlorine gas is 10L / h, and the reaction is controlled The temperature is 50°C, the molar ratio of chlorine gas to pyridone is 1.05:1, the reaction time is about 1h, then the temperature is raised to 160°C, and the temperature is kept for 2h to obtain pyridinol chlorobenzene liquid, to which DMF (accounting for 12% by weight of pyridine) is added ) for the next reaction.

[0025] Synthesis of 2-chloro-5-methylpyridine: Put 50g of chlorobenzene into a 500mL six-necked bottle equipped with a ther...

Embodiment 3

[0026] Embodiment 3 (adopting phosphorus oxychloride is chlorinating agent)

[0027] Raw material preparation: Weigh 1000g of pyridone with a content of 95%, put it into a four-necked bottle containing 1000g of chlorobenzene, stir to make it completely dissolve and set aside.

[0028] Synthesis of pyridinol: The reaction process adopts a continuous flow microchannel reactor, and feeds at the same time according to the ratio of 1:1.05 of the raw material pyridone chlorobenzene liquid and chlorine gas. The temperature of the first three plates is 50°C, and the temperature of the last three plates is 160°C. On the fourth plate, pump an aqueous solution of sodium carbonate (10% sodium carbonate content) equal to the quality of pyridone. Controlling the residence time of reaction material by the flow rate of pump is 90s, and pyridinol chlorobenzene liquid discharges and collects continuously, adds DMF (accounting for 12% of pyridine weight) wherein to be used for next step reaction...

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Abstract

The invention belongs to the technical field of organic chemical industry, and relates to the preparation method of 2-chloro-5-picoline, in particular to a method for preparing the 2-chloro-5-picolineby taking 5-methyl-3,4-dihydropyridine-2(1H)-ketone (hereinafter referred to as pyridone) and chlorine as raw materials, synthesizing 2-hydroxy-5-picoline (hereinafter referred to as pyridol) first and then conducting chlorination.

Description

technical field [0001] The invention belongs to the technical field of organic chemical industry, relates to the preparation method of 2-chloro-5-picoline, more specifically, relates to a kind of 5-methyl-3,4-dihydropyridine-2(1H)-one (hereinafter referred to as: pyridone) and chlorine as raw materials, first synthesize 2-hydroxyl-5-picoline (hereinafter referred to as: pyridinol), and then chlorinate the method for preparing 2-chloro-5-picoline. 2-Chloro-5-methylpyridine is a very valuable organic intermediate, which has been widely used in pesticides, medicines, fine chemicals and other fields. Background technique [0002] The synthetic routes of 2-chloro-5-picoline mainly include direct chlorination method, ring method, 3-picoline oxidation method, diazotization method and so on. Among them, the ring method is the main industrial synthesis method. [0003] Cycling method: There are two synthetic routes. The first one uses benzylamine and propionaldehyde as raw material...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
Inventor 徐林孙诚丁克鸿王怡明王根林黄杰军李明
Owner JIANGSU YANGNONG CHEM GROUP
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