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2,3,5,6-tetrachloropyridine synthesis and separation method

A technology of tetrachloropyridine and synthesis method, which is applied in the field of 2,3,5,6-tetrachloropyridine synthesis and separation, can solve the problems of large investment in reaction equipment, high process requirements, increased production cost, etc., and achieves improved electrocatalysis Activity, high product purity, low environmental pollution effect

Inactive Publication Date: 2019-09-13
潍坊新绿化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the industrial pyridine chlorination process mainly uses the pyridine direct chlorination method. The pyridine direct chlorination method is divided into the pyridine liquid phase chlorination method and the pyridine gas phase chlorination method. The earlier process uses liquid phase chlorination. This method produces Pyridine chloride needs to be carried out under higher temperature and pressure, the process requirements are high, the investment in reaction equipment is large, and the production cost is greatly increased

Method used

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  • 2,3,5,6-tetrachloropyridine synthesis and separation method
  • 2,3,5,6-tetrachloropyridine synthesis and separation method

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Embodiment 1

[0020] A kind of 2,3,5,6-tetrachloropyridine synthetic method, comprises the following operation steps:

[0021] (1) Heat pyridine and chlorine gas to 200°C respectively according to the molar ratio of 2:4, and the vaporized pyridine and chlorine gas are passed into the primary chlorination reactor with an internal temperature of 300°C. After reacting for 50 seconds, the reaction gas All pass into the quenching tower, collect 2-chloropyridine and 2,6-dichloropyridine in the liquid phase in the quenching tower;

[0022] (2) After heating 2-chloropyridine and 2,6-dichloropyridine to 250°C to vaporize, introduce the gas into the intermediate chlorination reactor with an internal temperature of 340°C, and pass excess chlorine gas into it, and stay for 25 seconds to react Finally, the mixed gas is passed into the quench tower to obtain 2,3,6-trichloropyridine and 2,3,5-trichloropyridine in the liquid phase;

[0023] (3) After heating the 2,3,6-trichloropyridine and 2,3,5-trichloro...

Embodiment 2

[0029] A kind of 2,3,5,6-tetrachloropyridine synthetic method, comprises the following operation steps:

[0030] (1) Heat pyridine and chlorine gas to 230°C according to the ratio of molar ratio of 2:6, and the vaporized pyridine and chlorine gas are passed into the primary chlorination reactor with an internal temperature of 350°C. After reacting for 60 seconds, the reaction gas All pass into the quenching tower, collect 2-chloropyridine and 2,6-dichloropyridine in the liquid phase in the quenching tower;

[0031] (2) After heating 2-chloropyridine and 2,6-dichloropyridine to 260°C to vaporize, introduce the gas into the intermediate chlorination reactor with an internal temperature of 380°C, and pass excess chlorine gas into it, and stay for 30 seconds to react Finally, the mixed gas is passed into the quench tower to obtain 2,3,6-trichloropyridine and 2,3,5-trichloropyridine in the liquid phase;

[0032] (3) After heating the 2,3,6-trichloropyridine and 2,3,5-trichloropyri...

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Abstract

The invention discloses a 2,3,5,6-tetrachloropyridine synthesis and separation method, which comprises the following operation steps: (1) introducing gasified pyridine and chlorine into a primary chlorination reactor to prepare 2-chloropyridine and 2,6-dichloropyridine; (2) gasifying 2-chloropyridine and 2,6-dichloropyridine by heating to prepare 2,3,6-trichloropyridine and 2,3,5-trichloropyridine; (3) gasifying the liquid-phase 2,3,6-trichloropyridine and 2,3,5-trichloropyridine, introducing products into a high-grade chlorination reactor, introducing excessive chlorine, continuously distilling to obtain tetrachloropyridine in a crude product tower and pentachloropyridine at the tower bottom; (4) adding pentachloropyridine into a high pressure reactor, adding zinc dust and 31% industrialhydrochloric acid to obtain 2,3,5,6-tetrachloropyridine; and (5) letting the tetrachloropyridine obtained after distillation in the crude product tower undergo electrolytic reaction to prepare the 2,3,5,6-tetrachloropyridine. The 2,3,5,6-tetrachloropyridine synthesis and separation method provided by the invention has the following advantages: utilization rate of the raw materials is high, productpurity is high, the process is simple, and the environmental pollution is low.

Description

technical field [0001] The technical field of chemical pesticide preparation of the present invention particularly relates to a synthesis and separation method of 2,3,5,6-tetrachloropyridine. Background technique [0002] 2,3,5,6-Tetrachloropyridine is a valuable commercial product and a very important chemical intermediate, which can be used in the production of insecticides and also in the preparation of low-toxicity and high-efficiency organophosphorus pesticides Chlorpyrifos can also be used to produce α-[4-(3,5,6-trichloropyridine-2-phthaloxy)-phenoxy]-alkane carboxylic acid and its derivatives with high herbicidal efficiency. At present, the industrial pyridine chlorination process mainly uses the pyridine direct chlorination method. The pyridine direct chlorination method is divided into the pyridine liquid phase chlorination method and the pyridine gas phase chlorination method. The earlier process uses liquid phase chlorination. This method produces Pyridine chlori...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61C25B3/04C25B3/25
CPCC07D213/61C25B3/25
Inventor 曲波王强杨洪强田俊杰张金旺
Owner 潍坊新绿化工有限公司
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