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Method for synthesizing 2,3-dichloropyridine

A synthesis method and technology of dichloropyridine, applied in directions such as organic chemistry, can solve the problems of high price, high quality ratio and high cost, and achieve the effect of high industrialization value

Active Publication Date: 2018-05-08
CHONGQING ZHONGBANG TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] JP1193246, CN103145609A, etc. use 2,3,6-trichloropyridine as raw material, adopt one of palladium, platinum, ruthenium, Raney nickel or Raney copper, etc. as a catalyst, and reduce 2,3,6 with reducing agents such as hydrogen. -Trichloropyridine to obtain 2,3-dichloropyridine, the problem is that the single-pass conversion rate of 2,3,6-trichloropyridine and the selectivity of 2,3-dichloropyridine are not high, and the separation is difficult
However, in the system, the amount of catalyst used is large, and the mass ratio of catalyst to 2,3,6-trichloropyridine is as high as 1:11, and three (triphenylphosphine) rhodium chloride (I) is a kind of expensive catalyst. The amount of catalyst described in the example of WO2017085476 is expensive to prepare 2,3-dichloropyridine and has no industrial production value

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] In a 250ml autoclave, put 30g2,3,6-trichloropyridine, 90g ethanol, 30g triethylamine, 0.5g tris(triphenylphosphine)rhodium chloride (I), 1g triphenylphosphine into Nitrogen replaces the air in the reaction kettle. After the replacement, hydrogen is passed through and the temperature is raised to 80°C for reaction. During the reaction, the reaction pressure gradually decreases, and hydrogen is added to maintain the reaction pressure between 0.8 and 1.0 MPa. The reaction is continued for 20 hours, and the reaction ends. Sampling and analysis showed that the conversion rate of 2,3,6-trichloropyridine was 97%, the selectivity of 2,3-dichloropyridine was 89%, and the yield of 2,3-dichloropyridine was 86.3%.

Embodiment 2

[0021] In a 250ml autoclave, drop into 30g2,3,6-trichloropyridine, 90g ethanol, 30g triethylamine, 0.08g tris(triphenylphosphine) rhodium chloride (I), 0.2g triphenylphosphine, pass Inject nitrogen to replace the air in the reactor. After the replacement, pass hydrogen and raise the temperature to 83°C for reaction. During the reaction, the reaction pressure gradually decreases. Add hydrogen to maintain the reaction pressure between 0.8 and 1.0 MPa. Continue the reaction for 26 hours, and the reaction ends. Sampling and analysis showed that the conversion rate of 2,3,6-trichloropyridine was 93%, the selectivity of 2,3-dichloropyridine was 89%, and the yield of 2,3-dichloropyridine was 82.8%.

Embodiment 3

[0023] In a 250ml autoclave, drop into 30g2,3,6-trichloropyridine, 90g ethanol, 30g triethylamine, 0.08g tris(triphenylphosphine) rhodium chloride (I), 0.3g triphenylphosphine, pass Inject nitrogen to replace the air in the reaction kettle. After the replacement, pass hydrogen and raise the temperature to 83°C for reaction. During the reaction, the reaction pressure gradually decreases. Add hydrogen to maintain the reaction pressure between 0.8 and 1.0 MPa. Continue the reaction for 24 hours, and the reaction ends. The conversion rate of 2,3,6-trichloropyridine was 95%, the selectivity of 2,3-dichloropyridine was 90%, and the yield of 2,3-dichloropyridine was 85.5%.

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PUM

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Abstract

The invention discloses a method for synthesizing 2,3-dichloropyridine. The method comprises the steps that under the existence of solvent and an acid-binding agent, 2,3,6-trichloropyridine is taken as a raw material, oxygen is taken as a hydrogen source, rhodium(I) tris(triphenylphosphine) chloride or bromotris(triphenylphosphine)rhodium(I) is taken as a catalyzer, an organic phosphine-containingauxiliary is added, and catalytic hydrogenation is conducted under the conditions that the pressure is 0.8-8 MPa and the temperature is 20-200 DEC G to obtain the 2,3-dichloropyridine. According to the method, by adding the low-cost organic phosphine-containing auxiliary, under the conditions that using amount of the catalyzer rhodium(I) tris(triphenylphosphine) chloride or the bromotris(triphenylphosphine)rhodium(I) is greatly reduced, better percent conversion of the raw material 2,3,6-trichloropyridine and better selectivity of the product 2,3-dichloropyridine are still obtained, the percent conversion of the 2,3,6-trichloropyridine reaches 97% and the selectivity of the 2,3-dichloropyridine is close to 90%, so that production cost of the 2,3-dichloropyridine is greatly reduced, and the method has higher industrialization value.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a synthesis method of 2,3-dichloropyridine. Background technique [0002] 2,3-Dichloropyridine is an important fine chemical intermediate and a key intermediate for the synthesis of the new insecticide chlorantraniliprole. [0003] JP1193246, CN103145609A, etc. use 2,3,6-trichloropyridine as raw material, adopt one of palladium, platinum, ruthenium, Raney nickel or Raney copper as catalyst, and reduce 2,3,6 with reducing agents such as hydrogen -Trichloropyridine to obtain 2,3-dichloropyridine, the problem is that the one-way conversion rate of 2,3,6-trichloropyridine and the selectivity of 2,3-dichloropyridine are not high, and the separation is difficult. [0004] WO2017085476 uses 2,3,6-trichloropyridine as a raw material, tris(triphenylphosphine)rhodium(I) chloride as a catalyst, and performs a homogeneous catalytic hydrogenation reaction in the presence of an ac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 陈洪龙桂清王平钱勇韩小军薛谊
Owner CHONGQING ZHONGBANG TECH CO LTD