A kind of preparation method of 2,4-dichlorobenzoyl chloride

Abstract

The invention provides a preparation method of 2,4-dichlorobenzoyl chloride, relates to the technical field of fine chemical organic synthesis, comprising the following steps: (1) under the action of catalyst azobisisobutyronitrile, 2,4-dichlorobenzoyl chloride Chlorotoluene and chlorine generation chlorination reaction, prepare 2,4 dichlorobenzotrichlorotoluene crude product; (2) 2,4 dichlorobenzotrichlorotoluene crude product prepared in step (1) and water hydrolysis reaction; (3 ) the hydrolyzate of step (2) is rectified under reduced pressure, and the cuts in the collection area are used to prepare the target product 2,4-dichlorobenzoyl chloride. The process raw materials of the present invention are easy to get, cheap, simple to operate, and low in energy consumption , the product quality is high, the production cost is low, the three wastes are less, the total product yield is between 90%-95%, and the purity is more than 99%. It is suitable for industrial production and has a good application prospect.

Description

technical field

[0001] The invention relates to the technical field of fine chemical organic synthesis, in particular to a preparation method of 2,4-dichlorobenzoyl chloride. Background technique

[0002] 2,4-Dichlorobenzoyl chloride, colorless to light yellow liquid or solid, melting point 16-18°C, CAS: 89-75-8, molecular formula C 7 h 3 Cl 3 O, is an important medicine, pesticide, dye intermediate, the structural formula is as follows:

[0003]

[0004] Because 2,4-dichlorobenzoyl chloride is more and more used in multiple fields as a raw material, this result impels the market to increase year by year the demand for 2,4-dichlorobenzoyl chloride, and has a broad application prospect. Therefore , more and more attention has been paid to the research on the preparation method of 2,4-dichlorobenzoyl chloride.

[0005] 2,4-dichlorobenzoyl chloride mainly has the following synthetic routes:

[0006] (1) Obtained by reacting 2,4-dichlorobenzoic acid with chlorine sulfite...

Examples

Embodiment 1

[0032] In a 500ml four-neck flask, assemble a stirring, chlorine pipe, thermometer, glass tube cooler, and upper exhaust gas absorption device, and 300g of 2,4-dichlorotoluene, 0.75g of azobisisobutyronitrile, Close the reaction system, turn on the vacuum pump connected to the reaction system to make the system in a state of slight negative pressure, start to adjust the temperature to 95°C, then slowly open the chlorine gas valve, and start to flow chlorine gas at a speed of 500ml / min, and then pour chlorine gas into the four-necked flask after 2 hours The remaining 0.75 g of azobisisobutyronitrile was added dropwise in batches, once an hour, followed by GC gas chromatography after 4 hours, and the end point was when the amount of 2,4-dichlorotoluene was ≤0.05%. Stop the chlorine gas flow, then start to blow off the chlorine gas and hydrogen chloride gas in the system, and then measure 489.2g of the obtained chlorinated liquid, analyze the content of 2,4-dichlorotrichlorobenzyl...

Embodiment 2

[0036] In a 500ml four-neck flask, assemble a stirring, chlorine pipe, thermometer, glass tube cooler, and upper exhaust gas absorption device, and 300g of 2,4-dichlorotoluene, 0.75g of azobisisobutyronitrile, Close the reaction system, turn on the vacuum pump connected to the reaction system to make the system in a state of slight negative pressure, start to adjust the temperature to 95°C, then slowly open the chlorine gas valve, and start to flow chlorine gas at a speed of 400ml / min, and then pour chlorine gas into the four-necked flask after 2 hours The remaining 0.75 g of azobisisobutyronitrile was added dropwise in batches, once an hour, followed by GC gas chromatography after 5 hours, and the end point was when the amount of 2,4-dichlorotoluene was ≤0.05%. Stop the chlorine gas flow, then start to blow off the chlorine gas and hydrogen chloride gas in the system, and then measure 489.8g of the obtained chlorinated liquid, and the content of 2,4-dichlorotrichlorobenzyl is ...

Embodiment 3

[0040] In a 500ml four-neck flask, assemble a stirring, chlorine pipe, thermometer, glass tube cooler, and upper exhaust gas absorption device, and 300g of 2,4-dichlorotoluene, 0.75g of azobisisobutyronitrile, Close the reaction system, turn on the vacuum pump connected to the reaction system to make the system in a state of slight negative pressure, start to adjust the temperature to 95°C, then slowly open the chlorine gas valve, and start to flow chlorine gas at a speed of 600ml / min, and then pour chlorine gas into the four-necked flask after 2 hours The remaining 0.75 g of azobisisobutyronitrile was added dropwise once an hour, followed by GC gas chromatography after 3 hours, and the end point was when the amount of 2,4-dichlorotoluene was ≤0.05%. Stop the chlorine gas flow, then start to blow off the chlorine gas and hydrogen chloride gas in the system, and then measure 488.3g of the obtained chlorinated liquid, analyze the content of 2,4-dichlorotrichlorobenzyl to 98.9%, a...

technical field

[0001] The invention relates to the technical field of fine chemical organic synthesis, in particular to a preparation method of 2,4-dichlorobenzoyl chloride. Background technique

[0002] 2,4-Dichlorobenzoyl chloride, colorless to light yellow liquid or solid, melting point 16-18°C, CAS: 89-75-8, molecular formula C 7 h 3 Cl 3 O, is an important medicine, pesticide, dye intermediate, the structural formula is as follows:

[0003]

[0004] Because 2,4-dichlorobenzoyl chloride is more and more used in multiple fields as a raw material, this result impels the market to increase year by year the demand for 2,4-dichlorobenzoyl chloride, and has a broad application prospect. Therefore , more and more attention has been paid to the research on the preparation method of 2,4-dichlorobenzoyl chloride.

[0005] 2,4-dichlorobenzoyl chloride mainly has the following synthetic routes:

[0006] (1) Obtained by reacting 2,4-dichlorobenzoic acid with chlorine sulfite...

Examples

Embodiment 1

[0032] In a 500ml four-neck flask, assemble a stirring, chlorine pipe, thermometer, glass tube cooler, and upper exhaust gas absorption device, and 300g of 2,4-dichlorotoluene, 0.75g of azobisisobutyronitrile, Close the reaction system, turn on the vacuum pump connected to the reaction system to make the system in a state of slight negative pressure, start to adjust the temperature to 95°C, then slowly open the chlorine gas valve, and start to flow chlorine gas at a speed of 500ml / min, and then pour chlorine gas into the four-necked flask after 2 hours The remaining 0.75 g of azobisisobutyronitrile was added dropwise in batches, once an hour, followed by GC gas chromatography after 4 hours, and the end point was when the amount of 2,4-dichlorotoluene was ≤0.05%. Stop the chlorine gas flow, then start to blow off the chlorine gas and hydrogen chloride gas in the system, and then measure 489.2g of the obtained chlorinated liquid, analyze the content of 2,4-dichlorotrichlorobenzyl...

Embodiment 2

[0036] In a 500ml four-neck flask, assemble a stirring, chlorine pipe, thermometer, glass tube cooler, and upper exhaust gas absorption device, and 300g of 2,4-dichlorotoluene, 0.75g of azobisisobutyronitrile, Close the reaction system, turn on the vacuum pump connected to the reaction system to make the system in a state of slight negative pressure, start to adjust the temperature to 95°C, then slowly open the chlorine gas valve, and start to flow chlorine gas at a speed of 400ml / min, and then pour chlorine gas into the four-necked flask after 2 hours The remaining 0.75 g of azobisisobutyronitrile was added dropwise in batches, once an hour, followed by GC gas chromatography after 5 hours, and the end point was when the amount of 2,4-dichlorotoluene was ≤0.05%. Stop the chlorine gas flow, then start to blow off the chlorine gas and hydrogen chloride gas in the system, and then measure 489.8g of the obtained chlorinated liquid, and the content of 2,4-dichlorotrichlorobenzyl is ...

Embodiment 3

[0040] In a 500ml four-neck flask, assemble a stirring, chlorine pipe, thermometer, glass tube cooler, and upper exhaust gas absorption device, and 300g of 2,4-dichlorotoluene, 0.75g of azobisisobutyronitrile, Close the reaction system, turn on the vacuum pump connected to the reaction system to make the system in a state of slight negative pressure, start to adjust the temperature to 95°C, then slowly open the chlorine gas valve, and start to flow chlorine gas at a speed of 600ml / min, and then pour chlorine gas into the four-necked flask after 2 hours The remaining 0.75 g of azobisisobutyronitrile was added dropwise once an hour, followed by GC gas chromatography after 3 hours, and the end point was when the amount of 2,4-dichlorotoluene was ≤0.05%. Stop the chlorine gas flow, then start to blow off the chlorine gas and hydrogen chloride gas in the system, and then measure 488.3g of the obtained chlorinated liquid, analyze the content of 2,4-dichlorotrichlorobenzyl to 98.9%, a...

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