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Preparation method of 2, 6-difluorobenzamide

A technology of difluorobenzamide and difluorobenzonitrile, which is applied in the field of preparation of 2,6-difluorobenzamide, can solve problems such as environmental pollution, product instability, backward technology, etc., and achieve economic benefits, The effect of saving production cost and reasonable process

Inactive Publication Date: 2020-09-22
XIANTAO XIANSHENG FINE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the domestic production process of 2,6-difluorobenzamide is backward, the environment is seriously polluted, and the product is unstable, which cannot meet the needs of domestic and foreign markets.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] A preparation method for 2,6-difluorobenzamide, comprising the following steps:

[0018] 1) Add 16 parts (all parts by mass in this article) of 2,6-dichlorobenzonitrile, 40 parts of dimethylformamide, and 1 part of catalyst into the reaction kettle and stir. After stirring, add 15 parts of potassium fluoride and heat up to 170°C, keep it for 6 hours, then cool down to room temperature, filter, oil pump vacuum distillation, and rectification to obtain 2,6-difluorobenzonitrile;

[0019] 2) Carry out the hydrolysis reaction, the 2,6-difluorobenzonitrile obtained in step 1), 6% sodium hydroxide aqueous solution, stir and heat and add 30% hydrogen peroxide, keep the reaction temperature at 35°C for 2 hours Cool down to room temperature, neutralize with dilute hydrochloric acid, filter, wash and dry to obtain 2,6-difluorobenzamide.

[0020] The present invention obtains 2,6-difluorobenzonitrile with a purity of 99% through the above steps.

[0021] The catalyst in the step ...

Embodiment 2

[0026] A preparation method for 2,6-difluorobenzamide, comprising the following steps:

[0027] 1) Add 21 parts of 2,6-dichlorobenzonitrile, 50 parts of dimethylformamide, and 2 parts of catalyst into the reaction kettle and stir. After stirring, add 18.375 parts of potassium fluoride, raise the temperature to 172°C, keep it for 6 hours and then drop to room temperature, filter, oil pump vacuum distillation, and rectification to obtain 2,6-difluorobenzonitrile;

[0028] 2) Carry out the hydrolysis reaction, the 2,6-difluorobenzonitrile obtained in step 1), 7% sodium hydroxide aqueous solution, stir and heat, add 30% hydrogen peroxide, keep the reaction temperature at 45 ° C, keep it for 3 hours and then drop After reaching room temperature, neutralizing with dilute hydrochloric acid, filtering, washing and drying, 2,6-difluorobenzamide was obtained.

[0029] The present invention obtains 2,6-difluorobenzonitrile with a purity of 99% through the above steps.

[0030] The cata...

Embodiment 3

[0035] A preparation method for 2,6-difluorobenzamide, comprising the following steps:

[0036] 1) Add 25 parts of 2,6-dichlorobenzonitrile, 60 parts of dimethylformamide, and 2 parts of catalyst into the reaction kettle and stir. After stirring, add 20 parts of potassium fluoride, raise the temperature to 175°C, keep it for 6 hours, and then cool down to room temperature, filter, oil pump vacuum distillation, and rectification to obtain 2,6-difluorobenzonitrile;

[0037] 2) Carry out the hydrolysis reaction, the 2,6-difluorobenzonitrile obtained in step 1), 8% sodium hydroxide aqueous solution, stir and heat, add 30% hydrogen peroxide, keep the reaction temperature at 55 ° C, keep it for 3 hours and then drop After reaching room temperature, neutralizing with dilute hydrochloric acid, filtering, washing and drying, 2,6-difluorobenzamide was obtained.

[0038] The present invention obtains 2,6-difluorobenzamide with a purity of 99% through the above steps.

[0039] The catal...

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PUM

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Abstract

The invention provides a preparation method of 2, 6-difluorobenzamide. The preparation method comprises the following steps: adding 2, 6-dichlorobenzonitrile, dimethylformamide and a catalyst into a reaction kettle and stirring; adding potassium fluoride after stirring, and heating to 170-175 DEG C, cooling to room temperature, carrying out reduced pressure filter pressing by an oil pump, distilling, rectifying to obtain 2, 6-difluorobenzonitrile, continuing to add a sodium hydroxide aqueous solution, stirring, heating, adding 30% hydrogen peroxide, keeping the reaction temperature at 35-55 DEG C, cooling to room temperature, neutralizing by diluted hydrochloric acid, filtering, washing, and drying to obtain 2, 6-difluorobenzamide. The process is reasonable, dimethyl formamide waste gas isgenerated in the distillation process, the dimethyl formamide is obtained after the waste gas passes through the condensing device, the raw materials are recycled, the production cost is saved, and the economic benefit is improved. In the production process, hydrolysis is carried out under an alkaline condition, so that the yield is not reduced, the problem that wastewater is difficult to treat after acidic hydrolysis is avoided, and the pollution to the environment is reduced.

Description

Technical field [0001] The invention relates to the technical field of fine chemicals, in particular to a preparation method of 2,6-difluorobenzamide. Background technique [0002] 2,6-Difluorobenzamide is a key intermediate in the synthesis of benzoylurea pesticides. Benzoylurea pesticides are chitin synthesis inhibitors and inhibit the bioavailability of chitin in insects. Synthetically lethal to insects. Its mechanism of action is different from other pesticides. It has the characteristics of high insecticidal activity, broad insecticidal effect, low residue, strong selectivity, and safety to humans and animals. Benzoylurea pesticides have been rapidly developed internationally, and pesticides have been developed. Diflubenzuron, fluflubenzuron, diflubenzuron, diflufenuron, fluflubenzuron, diflufenuron, fludiflubenzuron, fluflubenzuron, etc. The demand for high-quality 2,6-difluorobenzamide in domestic and foreign markets is growing rapidly. [0003] At present, the dom...

Claims

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Application Information

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IPC IPC(8): C07C233/65C07C231/06
CPCC07C231/06C07C233/65
Inventor 邵新华王荣洲何正江徐亚华
Owner XIANTAO XIANSHENG FINE CHEM
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