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Method for preparing 2,3 - dichloro - 5 - trichloro methylpyridine

A technology of trichloromethylpyridine and chlorination reaction, applied in 2 fields, can solve the problems of difficulty in synthesis, separation and purification of perhalogenated aldehydes, expensive raw material catalysts, difficulty in separating isomers and the like

Active Publication Date: 2007-12-26
LANZHOU CHEMSPECWEIER CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The synthesis methods mentioned in US4508907, US4555575, GC1599123 and other patent documents are as follows: 2-amino-5-picoline is used as raw material, and 2,3-dichloro-5-tri Chloromethylpyridine, its shortcoming is, raw material cost height, post-reaction processing separation isomer difficulty
[0004] The following technical scheme is disclosed in US4469896: use perhalogenated aldehyde and unsaturated nitrile as raw materials to synthesize 2,3-dichloro-5-trichloromethylpyridine, the disadvantage is that the raw material perhalogenated aldehyde is synthesized and separated It is difficult to purify
[0005] 2 in documents such as US4331811, US4636565, the synthetic method of 3-dichloro-5-trichloromethylpyridine adopts following steps: take 2-chloro-5-trichloromethylpyridine as raw material, in high-valent metal chloride catalyst and Under the presence of chlorine, chlorination synthesizes 2,3-dichloro-5-trichloromethylpyridine, but the disadvantage of this method is that when this method is used for preparation, the catalyst high-valent metal chloride is very easy to decompose by hygroscopicity, and the preparation Very difficult, very expensive, currently there is no product in China
According to the above method, the production cost is too high and the raw material catalyst is expensive and difficult to obtain, so that there are many difficulties in industrial realization

Method used

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preparation example Construction

[0049] (2) The preparation method of the present invention reacts with raw materials and catalysts that are easily available in industry with low price, stable chemical properties, and difficult to decompose by moisture absorption. The raw and auxiliary materials of the method are cheap and easy to obtain, the process is simple, and the aftertreatment is easy. The condition is mild, the pollution to the environment is small, and 2,3-dichloro-5-trichloromethylpyridine can be prepared in a relatively high yield, and at the same time, it is easy to industrialize.

[0050] (3) The catalyst high-valent metal chloride of the prior art is very easy to decompose by hygroscopicity, the preparation is very difficult, the price is very expensive, and there is no commercial product in China at present. However, the present invention adopts a new catalyst for chlorination reaction, thereby achieving higher yield, lowering cost and reducing environmental pollution.

Embodiment 1

[0054] Drop into 500g (2.2mol) 2-chloro-5-trichloromethylpyridine (molecular weight 231g / mol), 15g (3%wt) MoO 3 , stir well, at T 内 =170°C, feed Cl into the above solution 2 , The reaction was completed in 18 hours. The crude product of 2,3-dichloro-5-trichloromethylpyridine was adjusted to PH=8-9, washed, separated into layers, dried and distilled to obtain 449.4g of the product with a yield of 78.2%, and its boiling point b.p. was 104°C (2mmHg ).

Embodiment 2

[0056] Drop into 500g (2.2mol) 2-chloro-5-trichloromethylpyridine (molecular weight 231g / mol), 15g (3%wt) MoO 3 , stir well, at T 内 =250°C, feed Cl into the solution 2 , The reaction was completed in 10 hours. The crude 2,3-dichloro-5-trichloromethylpyridine was washed, adjusted to PH=8-9, separated, dried and distilled to obtain 244.2 g of the product with a yield of 42.5%.

[0057] The unchlorinated raw materials in this example are recycled for recycling.

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Abstract

This invention discloses a method for preparing 2, 3-dichloro-5-trichloromethyl pyridine. The method comprises: utilizing 2-chloro-5-trichloromethyl pyridine as the raw material, and chlorinating at 100-250 deg.C in the presence of inexpensive commercialized catalyst and chlorinating reagent to synthesize 2, 3-dichloro-5-trichloromethyl pyridine. The catalyst is commercialized, and is inexpensive. The method has such advantages as simple process, abundant and inexpensive raw material and catalyst, and high yield, and is suitable for mass production.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to the technical field of preparation methods of 2,3-dichloro-5-trichloromethylpyridine. Background technique [0002] 2,3-Dichloro-5-trichloromethylpyridine is a very valuable heterocyclic intermediate, which has been widely used in the fields of pesticides, medicines and fine chemicals. [0003] The synthesis methods mentioned in US4508907, US4555575, GC1599123 and other patent documents are as follows: 2-amino-5-picoline is used as raw material, and 2,3-dichloro-5-tri Chloromethylpyridine, its shortcoming is, the raw material cost height, the post-reaction treatment separation isomer difficulty. [0004] The following technical scheme is disclosed in US4469896: use perhalogenated aldehyde and unsaturated nitrile as raw materials to synthesize 2,3-dichloro-5-trichloromethylpyridine, the disadvantage is that the raw material perhalogenated aldehyde is synthesized and separated Th...

Claims

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Application Information

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IPC IPC(8): C07D213/61B01J23/28
Inventor 戴信培唐运宏
Owner LANZHOU CHEMSPECWEIER CHEM CO LTD
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