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

A technology of trichloromethylpyridine and chloromethylpyridine, which is applied in the field of organic synthesis and can solve problems such as difficult acquisition of raw materials, high production costs, and difficulties in industrialization

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

AI Technical Summary

Problems solved by technology

[0006] In summary, according to the methods listed above, there are the following disadvantages: the production cost is too high, the catalyst is expensive and the raw materials are not easy to obtain, so that there are many difficulties in the realization of industrialization

Method used

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preparation example Construction

[0074] (2) The preparation method of the present invention reacts with cheap and a large amount of commercialized raw materials that are easy to buy in industry, the raw and auxiliary materials of this method are cheap and easy to get, the process is simple, the one-step reaction directly makes the target product, and the post-treatment is easy. , mild conditions, less environmental pollution, can produce 2,3-dichloro-5-trichloromethylpyridine with a relatively high yield, and is easy to industrialize at the same time.

[0075] (3) In a preferred embodiment of the present invention, a new catalyst, namely molybdenum oxide catalyst, is used. It is not easy to absorb moisture and be hydrolyzed, reduces the degree of corrosion to the reaction vessel, has milder reaction conditions, achieves higher yield, reduces cost, and reduces environmental pollution.

Embodiment 1

[0079] Drop into 500g (3.08mol) 2-chloro-5-chloromethylpyridine (molecular weight 162g / mol), 25g (5%wt) MoO 2 , stir well, at T 内 =175°C, feed Cl into the above solution 2 , The reaction was completed in 29 hours. The crude 2,3-dichloro-5-trichloromethylpyridine was washed, adjusted to PH=8-9, separated, dried and distilled to obtain 651 g of the product with a yield of 79.7%.

Embodiment 2

[0081] 500g (3.08mol) 2-chloro-5-chloromethylpyridine (molecular weight 162g / mol), 0.5g (0.1%wt) MoO 2 , stir well, at T 内 =100°C, feed Cl into the above solution 2 , 80 hours to complete the reaction. The crude 2,3-dichloro-5-trichloromethylpyridine was washed, subjected to pH=8-9, separated, dried, and distilled to obtain 93.2 g of the product with a yield of 11.4%.

[0082] The incompletely chlorinated product of the present invention can be recycled for recycling until the desired yield is achieved.

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PUM

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Abstract

This invention discloses a method for preparing 2, 3-dichloro-5-trichloromethyl pyridine. The method comprises: utilizing inexpensive commercialized 2-chloro-5-trichloromethyl pyridine as the raw material, and chlorinating at 100-250 deg.C in the presence of catalyst and Cl2 to synthesize 2, 3-dichloro-5-trichloromethyl pyridine. The catalyst is commercialized, and is inexpensive. The method has such advantages as simple process and high yield, and can synthesize 2, 3-dichloro-5-trichloromethyl pyridine in one step.

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] US4508907, US4555575, GC1599123 and other patent documents refer to the following synthetic methods: 2-amino-5-picoline is used as raw material to synthesize 2,3-dichloro-5-trichloro The disadvantages of picoline are: the cost of raw materials is high, and it is difficult to separate isomers after the reaction. [0004] The following method is disclosed in US4469896: take perhalogenated aldehyde and unsaturated nitrile as raw materials to synthesize 2,3-dichloro-5-trichloromethylpyridine, and its disadvantages are: raw material perhalogenated aldehyde synthesis and separation and purifica...

Claims

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Application Information

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IPC IPC(8): C07D213/61B01J23/28B01J27/10
Inventor 戴信培张京唐运宏
Owner LANZHOU CHEMSPECWEIER CHEM CO LTD
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