69045-83-6Relevant articles and documents
Synthesis method of 2, 3-dichloro-5-trichloromethylpyridine
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Paragraph 0037-0058, (2021/06/13)
The invention discloses a synthesis method of 2, 3-dichloro-5-trichloromethylpyridine, which is characterized in that a microreactor is used as a chlorination reaction channel, the first half of the microreactor channel is used as a primary chlorination channel, and the second half of the microreactor channel is filled with a catalyst B as a secondary chlorination reaction channel. The method comprises the following steps of firstly, fully mixing 2-chloro-5-methylpyridine with a catalyst A in a mixing chamber, then continuously reacting with chlorine through a primary chlorination channel to obtain 2-chloro-5-trichloromethylpyridine, then reacting through a secondary chlorination channel to obtain a crude oil layer of 2, 3-dichloro-5-trichloromethylpyridine, and carrying out alkali washing, dechlorination and rectification on the crude oil layer to obtain the high-concentration 2, 3 -dichloro-5-trichloromethylpyridine with the total yield to be 82-93%. According to the method, the technological process is simple, amplification production can be carried out through parallel connection, the catalyst B can be recycled and reused, the chlorination time is remarkably shortened, the chlorine utilization rate is increased, the post-treatment difficulty of the product is reduced, and the synthesis cost of 2, 3-dichloro-5-trichloromethylpyridine is saved.
Method for preparing 2, 3, 6-trichloropyridine
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Paragraph 0054; 0055, (2019/05/22)
The invention discloses a preparation method of 2, 3, 6-trichloropyridine. The preparation method comprises the following steps: taking 3-methylpyridine and chlorine as raw materials and preparing 2,3, 6-trichloropyridine through catalytic one-step gas-phase chlorination and trichloromethyl removal by a molecular sieve catalyst in the presence of water vapor. The molecular sieve catalyst is prepared by taking raw molecular sieve powder as an active component. The raw material 3-methylpyridine adopted in the invention is a byproduct in the synthesis of pyridine by an aldehyde ammonia method, and the source is cheap and easy to obtain. The molecular sieve catalyst has strong treatment capacity, the 3-methylpyridine and the chlorine are used as the raw materials, a proper amount of water isadded, gas-phase chlorination and trichloromethyl removal reactions are carried out under the action of a molecular sieve acid center and water vapor molecules, and the 2, 3, 6-trichloropyridine is synthesized by one step. The process is simple, the product purity and conversion rate are high, the yield can be maintained at 85% or above generally, the maximum yield can reach up to 95%, and the preparation method of the 2, 3, 6-trichloropyridine has good industrial application prospect.
Synthetic method of 2,3-dichloro-5-trichloromethyl pyridine
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Paragraph 0020-0021; 0022; 0023; 0025, (2019/07/04)
The invention provides a preparation method of 2,3-dichloro-5-trichloromethyl pyridine. The preparation method comprises the following steps: carrying out chlorination reaction on 2-chloro-5-chloromethyl pyridine and a chlorination reagent at 1-8 atm at the temperature of 100-250 DEG c in the presence of a catalyst, and distilling to obtain the 2,3-dichloro-5-trichloromethyl pyridine; the preparation method disclosed by the invention has the advantages that raw materials are cheap, the operation is simple, the post-treatment is convenient, the purity and the yield are relatively high, and large-scale industrial production can be carried out. The used catalyst is oxides, chlorides or chlorine oxides of manganese, iron, cobalt and ruthenium. No solvent is added, and the use amount of the catalyst is small. The mixed catalyst is used to avoid excessive use of a single expensive catalyst, and the catalyst can be recycled. Effective components in the residues can be extracted, and waste isavoided. The method disclosed by the invention has the advantages that the reaction window is wide, and the intermediate which is not completely converted can be distilled out and can be continuouslyused.
