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Method for preparing 2,5-dichlorobenzonitrile, special catalyst and preparation method thereof

A technology of dichlorobenzonitrile and catalyst, which is applied in the field of preparing 2,5-dichlorobenzonitrile, can solve the problems of harsh reaction conditions, long reaction time, complicated post-treatment, etc., and achieves improved selectivity, simple preparation method and environmental protection. friendly effect

Active Publication Date: 2021-09-24
武汉绿本科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, since chlorine can have a greater impact on the reactivity of other groups on the benzene ring as a passivating group, the use of common chloromethylation reagents does not react substantially when dichlorobenzene is chloromethylated. Looking for efficient chloromethylation reagents; Wang Xiaoying from Xiangtan University used chlorosulfonic acid and paraformaldehyde as chloromethylation reagents to successfully realize the chloromethylation reaction of passivated aromatics. However, the reaction conditions were harsh, the reaction time was long, and post-treatment Complex, especially the reaction yield is low, only 30-50%

Method used

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  • Method for preparing 2,5-dichlorobenzonitrile, special catalyst and preparation method thereof
  • Method for preparing 2,5-dichlorobenzonitrile, special catalyst and preparation method thereof
  • Method for preparing 2,5-dichlorobenzonitrile, special catalyst and preparation method thereof

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Experimental program
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Embodiment 1

[0022]

[0023] Add 29.4g of p-dichlorobenzene, 7.8g of paraformaldehyde and 1.5g of formaldehyde solution in a 100ml three-necked flask, install a mechanical stirrer, connect an air condenser with a balloon on the upper end and a constant pressure tube with 14ml of chlorosulfonic acid respectively. Dropping funnel, react in ice-water bath at 0°C, slowly add chlorosulfonic acid dropwise, start the stirrer to stir, the mixture turns purple, after 1.5h dropwise addition, raise the temperature to 50°C for 48h reaction. After the reaction is over, add saturated sodium carbonate solution to completely neutralize the unreacted acid solution, then add a certain amount of methylene chloride to the flask to extract the product, and wash the mixed solution two to three times with saturated sodium chloride solution after liquid separation. The obtained organic layer solution was dried with anhydrous sodium sulfate to remove water, spin-dried the organic solvent, and distilled under red...

Embodiment 2

[0025] Add 24.5g of p-dichlorobenzene and 10g of formaldehyde solution to a 100ml three-necked flask, slowly add 30g of benzenesulfonyl chloride dropwise at 0°C, and raise the temperature to 60°C for 72h. After the reaction is over, add saturated sodium carbonate solution to completely neutralize the unreacted acid solution, then add a certain amount of methylene chloride to the flask to extract the product, and wash the mixed solution two to three times with saturated sodium chloride solution after liquid separation. The obtained organic layer solution was dried with anhydrous sodium sulfate to remove water, spin-dried the organic solvent, and distilled under reduced pressure with an oil pump. At 170° C., an oily colorless transparent liquid with a pungent smell was collected, with a yield of 78%.

Embodiment 3

[0027] Add 14.7g of p-dichlorobenzene and 9g of formaldehyde solution into a 100ml three-necked flask, slowly add 10g of p-toluenesulfonyl chloride dropwise at room temperature, and raise the temperature to 30°C for 60h. After the reaction is over, add saturated sodium carbonate solution to completely neutralize the unreacted acid solution, then add a certain amount of methylene chloride to the flask to extract the product, and wash the mixed solution two to three times with saturated sodium chloride solution after liquid separation. The obtained organic layer solution was dried with anhydrous sodium sulfate to remove water, spin-dried the organic solvent and distilled under reduced pressure with an oil pump. At 170° C., an oily colorless transparent liquid with a pungent smell was collected with a yield of 83%.

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Abstract

The invention discloses a method for preparing 2,5-dichlorobenzonitrile. The method comprises the following steps: 1) using p-dichlorobenzene and formaldehyde or / and paraformaldehyde as raw materials, in the process of chloromethylation and catalyst Under the action, the only chloromethylation product 2,5-dichlorobenzyl chloride is obtained by chloromethylation reaction; 2) the product 2,5-dichlorobenzyl chloride obtained in step 1) is used as raw material, and ammonia, oxygen Ammoxidation reaction occurs under the action of catalyst to obtain 2,5-dichlorobenzonitrile. The invention also discloses a special catalyst used in the above method for preparing 2,5-dichlorobenzonitrile and a preparation method thereof. Compared with other methods, the method of the invention has the advantages of cheap and easy-to-obtain reaction raw materials, simple and convenient process route, low reaction temperature, environmental friendliness, strong selectivity, high yield and the like. The special catalyst has high selectivity and activity; the preparation method is simple, the cost is low, and the catalyst has good thermal stability and mechanical strength, and can be used in both fixed-bed and fluidized-bed reactors.

Description

technical field [0001] The invention relates to a method for preparing 2,5-dichlorobenzonitrile, a special catalyst and a preparation method thereof. It belongs to the technical field of organic chemistry and also belongs to the technical field of organic fine chemicals. Background technique [0002] Dichlorobenzonitrile and its derivatives are important fine chemicals, which are widely used as raw materials and organic intermediates in pesticides, fungicides, herbicides, preservatives, surfactants, dyes, engineering plastics and photosensitive materials, etc. industry. Dichlorobenzonitrile has been developed into a dozen different products, mainly including 2,6-dichlorobenzonitrile, 2,4-dichlorobenzonitrile, 3,4-dichlorobenzonitrile, etc. There are also many downstream products of dichlorobenzonitrile. With dichlorobenzonitrile as raw material, it is relatively easy to obtain the corresponding dichlorobenzoic acid, dichlorobenzamide, difluorobenzonitrile, difluorobenzonit...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C253/28C07C255/50C07C17/32C07C25/02B01J23/883B01J23/86B01J23/34B01J27/199
Inventor 谢光勇黄驰游向前黄业迎熊焰张爱清李金林
Owner 武汉绿本科技有限公司
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