Method for producing pentachloropyridine

A technology of pentachloropyridine and pyridine, which is applied in the field of preparation of pentachloropyridine, can solve the problems of harsh reaction conditions, high process requirements, and increased production costs, and achieve high raw material utilization, high product purity, and low environmental pollution.

Inactive Publication Date: 2012-10-10
张苏侠
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the complexity of polychlorinated hydrocarbon ring legal process and harsh reaction conditions, it is not suitable for industrial production and use. In industry, pyridine direct chlorination method is often used. Pyridine direct chlorination method is divided into pyridine liquid phase chlorination method and pyridine gas phase chlorination method. The earlier process uses liquid-phase chlorination, which requires high temperature and pressure to produce pentachloropyridine, which requires high process requirements, large investment in reaction equipment, and greatly increased production costs; the latest production method uses pyridine gas-phase chlorination Gas-phase catalytic chlorination method is the most advanced synthetic method of pentachloropyridine at present. This method uses pyridine as raw material to produce pentachloropyridine through fluidized bed and fixed bed process, and the reaction temperature in fluidized bed and fixed bed must be controlled. The temperature is about 380°C-410°C, and the pressure is 0.10-0.12Mpa. Using activated carbon-supported cobalt chloride, barium chloride and lanthanum chloride as catalysts to chlorinate and synthesize pentachloropyridine, the reaction conversion rate of this method reaches 98%. , the selectivity of the product pentachloropyridine is 91%

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0010] Send a certain amount of pyridine into the vaporizer for vaporization. After the pyridine is vaporized, it is taken out of the vaporizer by nitrogen and mixed with chlorine in the mixer and then enters the fluidized bed. The molar ratio of the intake air is pyridine: chlorine: nitrogen = 2: 4: 16 At the same time, add cobalt chloride, barium chloride and lanthanum chloride supported by catalyst activated carbon, the amount is 1% of the total gas in the bed, adjust the temperature in the fluidized bed to 380 °C, the pressure is 0.12Mpa, and react for 1 hour ; Send the reacted gas into the fixed bed, maintain the same temperature and pressure as the fluidized bed, and add the same catalyst and chlorine as the fluidized bed, so that the first reacted gas and chlorine react again , time 1 hour, after the reaction is over, the mixed gas after the reaction in the fixed bed is sent to the receiver, condensed and then dried to obtain pentachloropyridine.

Embodiment 2

[0012] A certain amount of pyridine is sent into the vaporizer for vaporization. After the pyridine is vaporized, it is taken out of the vaporizer by nitrogen and mixed with chlorine in the mixer and then enters the fluidized bed. The molar ratio of the intake air is pyridine: chlorine: nitrogen = 2.5: 4.5: 20 At the same time, add cobalt chloride, barium chloride and lanthanum chloride supported by catalyst activated carbon, the amount is 2% of the total gas in the bed, adjust the temperature in the fluidized bed to 400 ° C, the pressure is 0.11Mpa, and react for 1 hour ; Send the reacted gas into the fixed bed, maintain the same temperature and pressure as the fluidized bed, and add the same catalyst and chlorine as the fluidized bed, so that the first reacted gas and chlorine react again , time 1 hour, after the reaction is over, the mixed gas after the reaction in the fixed bed is sent to the receiver, condensed and then dried to obtain pentachloropyridine.

Embodiment 3

[0014] A certain amount of pyridine is sent into the vaporizer for vaporization. After the pyridine is vaporized, it is taken out of the vaporizer by nitrogen and mixed with chlorine in the mixer and then enters the fluidized bed. The molar ratio of the intake air is pyridine: chlorine: nitrogen = 3: 5.5: 22 At the same time, add cobalt chloride, barium chloride and lanthanum chloride supported by catalyst activated carbon, the amount is 3% of the total gas in the bed, adjust the temperature in the fluidized bed to 410°C, and the pressure is 0.12Mpa, and react for 1 hour ; Send the reacted gas into the fixed bed, maintain the same temperature and pressure as the fluidized bed, and add the same catalyst and chlorine as the fluidized bed, so that the first reacted gas and chlorine react again , time 1 hour, after the reaction is over, the mixed gas after the reaction in the fixed bed is sent to the receiver, condensed and then dried to obtain pentachloropyridine.

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Abstract

The invention discloses a method for producing pentachloropyridine, and the method belongs to the field of agricultural chemical manufacture. The production method uses pyridine, nitrogen, chlorine, activated carbon-supported cobalt chloride, barium chloride and lanthanum chloride as raw materials, and produces pentachloropyridine by fluidized bed and fixed bed technologies. The reaction conditions are that the temperature of the fluidized bed and the fixed bed is in the range of 380 DEG C to 410 DEG C, the pressure is in the range of 0.10 to 0.12Mpa, the catalyst is the activated carbon-supported cobalt chloride, barium chloride and lanthanum chloride, the reaction transformation rate of the method reaches 98%, and the selectivity of the product pentachloropyridine is 91%. The production method has advantages of high utilization of raw materials, high product purity, simple process, and little environmental pollution, and is a relatively advanced synthetic method of pentachloropyridine at present.

Description

Technical field: [0001] The invention belongs to the field of pesticide manufacture, in particular to a method for preparing pentachloropyridine. Background technique: [0002] Pentachloropyridine, white or light yellow powder or crystal in appearance, molecular formula: C 5 Cl 5 N has a molecular weight of 251.32 and a melting point of 125°C. Pentachloropyridine is an important pesticide technical intermediate, pharmaceutical and fine chemical intermediate, and is widely used in the industrial synthesis of insecticides chlorpyrifos, chlorpyrifos-methyl and the intermediate of the herbicide triclopyr 3,5,6-trichloropyridine Pyridin-2-ol and fluroxypyr intermediate 3,5-dichloro-4-amino-6-fluoropyridinol; with the further development and application of halogenated pyridine compounds, the use of pentachloropyridine will become more and more wide. The synthesis routes of pentachloropyridine can be classified into two categories: one is the polychlorinated hydrocarbon ring me...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
Inventor 张苏侠
Owner 张苏侠
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