Preparation method of 3-chloropyridine

A technology of chloropyridine and trichloropyridine, which is applied in the field of preparation of important fine chemical intermediate 3-chloropyridine, can solve the problems of multiple synthesis steps, complex reaction types, and high raw material prices, and achieve high-efficiency separation and recovery technology and novel process routes simple effect

Active Publication Date: 2011-09-07
LIANHE CHEM TECH +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In view of this, in order to solve the problems of high price of raw materials, many synthesis steps and complicated reaction types in the above-mentioned existing preparation method of 3-chloropyridine, the present invention prov

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  • Preparation method of 3-chloropyridine

Examples

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Embodiment 1

[0032] Chlorination

[0033] Weigh 1480.0g of 2,6-dichloropyridine and anhydrous FeCl 3 89.2g was placed in a 2000ml four-necked flask and mixed and heated up. When the temperature reached 120~140℃, chlorine gas was introduced. After the reaction was complete, the temperature was lowered to 100℃, and vacuum distillation was carried out at -0.1MPa, the top temperature was 118~ The product fractions are collected at 124°C, and the low-concentration distillate produced during the rectification process can be applied to the next batch for re-reaction or applied to the next batch for re-rectification and purification. After the application, 1715.0 g of 2,3,6-trichloropyridine is finally obtained, the total yield after the application is 94.0%, and the purity is ≥99.5%.

[0034] Hydrogenation reaction

[0035] Put 557.8g of 2,3,6-trichloropyridine prepared in the chlorination reaction, 232.0g of triethylamine, 8.5g of palladium on carbon, and 1675g of toluene into the reactor at one time...

Embodiment 2

[0039] Chlorination

[0040] Weigh 299.2g of 2,6-dichloropyridine and 533.7g of the recovered fraction (of which 2,6-dichloropyridine accounts for 86.1%, 2,3,6-trichloropyridine accounts for 9%), and anhydrous AlCl 3 36.5g is placed in the reactor and mixed, and when the temperature is raised to 120~140℃, chlorine gas is introduced. After the reaction is completed, the temperature is lowered to 100℃, and vacuum distillation is carried out. The product fraction is collected at -0.1MPa and the top temperature is 118~124℃. , The low-concentration product steamed out can be applied to the next batch for re-reaction or applied to the next batch for re-rectification and purification; after the application, 890.7g of 2,3,6-trichloropyridine is finally obtained, and the total yield after application is 95.2%, with purity ≥99.5%.

[0041] Hydrogenation reaction

[0042] 1340g of the toluene solution containing 2,3,6-trichloropyridine recovered in Example 1 can be added with 410.5g of 2,3,6-...

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Abstract

The invention discloses a preparation method of 3-chloropyridine. 3-chloropyridine is a fine chemical engineering intermediate extensively used in the fields of medicine and pesticides. The preparation method comprises the following steps of: taking 2,6-dichloropyridine as a raw material and performing chlorination reaction to obtain 2,3,6-trichloropyridine; putting the 2,3,6-trichloropyridine, an acid-binding agent, a metal catalyst and an organic solvent into a reactor for performing hydrogenation reaction, wherein the mol ratio of the 2,3,6-trichloropyridine to the acid-binding agent is 1:(0.5-1.0); cooling the hydrogenation reaction liquid, adding water to dissolve the hydrochlorate of the acid-binding agent, filtering and standing to separate the water layer; extracting the organic solvent layer by aqueous acid at least more than three times; combining the extracted aqueous acid layers, thinning up with water, alkalizing for adjusting the pH value of the filtrate to be 7; and layering the filtrate to obtain the liquid product of 3-chloropyridine. The preparation method of 3-chloropyridine has a novel process route, short reaction steps, simplicity of operation, high yield, low production cost and environmental friendliness, and is suitable for industrialized production.

Description

Technical field [0001] The invention relates to a chemical synthesis method, in particular to a method for preparing 3-chloropyridine, an important fine chemical intermediate widely used in the fields of medicine and pesticides. Background technique [0002] 3-Chloropyridine is an important fine chemical intermediate, which is widely used in the fields of medicine and pesticides. [0003] About the synthetic method of 3-chloropyridine: [0004] Ciamician. Dennstedt in Chemische Berichte, 1882, vol. 15, p. 1179 discloses a series of synthetic methods for preparing 3-chloropyridine from pyrrole, carbon trichloride or carbon tetrachloride. [0005] Wibaut. Nicolai adopted the method of direct chlorination of pyridine in Recueil des Travaux Chimiques des Pays-Bas, 1939, vol. 58, p. 709-721, to synthesize 3-chloropyridine. However, this preparation method has many by-products. [0006] In Justus Liebigs Annalen der Chemie, 1931, vol.486, p.95, Raeth introduced 3-aminopyridine as a raw mater...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCY02P20/584
Inventor 王萍彭寅生樊小彬张俊涛
Owner LIANHE CHEM TECH
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