Preparation of 4-hydroxybenzoyl chloride

A technology of hydroxybenzoyl chloride and hydroxybenzoic acid, which is applied in the field of benzoyl chloride compounds, can solve the problems of low yield, low product purity, and increased production cost of 4-hydroxybenzoyl chloride, and achieve less steps and simple operation Effect

Inactive Publication Date: 2009-03-04
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the benzene ring is equipped with a very strong first-class positioning group hydroxyl group, it is difficult to prepare 4-hydroxybenzoyl chloride from 4-hydroxybenzoic acid as a raw material. At present, only Germany can prepare this product, but the yield is low. , according to literature reports only about 15%, and the purity of the product is not high
In order to obtain the 4-hydroxybenzoyl chloride of higher purity, the prior art adopts the method for underpressure distillation to steam the product, which also makes the production cost of 4-hydroxybenzoyl chloride greatly improved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Add 20 grams (0.145mol) of 4-hydroxybenzoic acid, 120mL of benzene and 40mL of N,N-dimethylformamide into a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stir to dissolve. Then, it was heated to 55° C., and 34 g (0.285 mol) of thionyl chloride was added dropwise for 0.5 h, and it was reacted for 4 h after the dropwise addition was completed. After the reaction is finished, cool and separate the liquids. The upper layer is mainly DMF, DMF hydrochloride and impurities, and the lower layer is mainly benzene, 4-hydroxybenzoyl chloride and a small amount of DMF. The solution in the lower layer was distilled at normal pressure first, and then distilled under reduced pressure to recover thionyl chloride and benzene. With the distillation of benzene, the raffinate in the distillation bottle solidified into a viscous solid, that is, 4-hydroxybenzoyl chloride. The purity of the product was analyzed. Greater than 97%, the yield is more than ...

Embodiment 2

[0018] Add 20 g (0.145 mol) of 4-hydroxybenzoic acid, 80 mL of benzene and 20 mL of N, N-dimethylformamide into a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stir to dissolve. Then, it was heated to 55° C., and 34 g (0.285 mol) of thionyl chloride was added dropwise for 0.5 h, and it was reacted for 4 h after the dropwise addition was completed. After the reaction is finished, cool and separate the liquids. Distill the lower layer solution at normal pressure first, then distill under reduced pressure to recover thionyl chloride and benzene. With the steaming of benzene, the raffinate in the distillation bottle solidifies into a viscous solid, that is, 4- Hydroxybenzoyl chloride. The yield is about 70%.

Embodiment 3

[0020] Add 20 grams (0.145mol) of 4-hydroxybenzoic acid, 120 mL of benzene and 4 mL of N, N-dimethylformamide into a four-neck flask equipped with a stirrer, a thermometer, and a reflux condenser, and stir to dissolve. Then, it was heated to 55° C., and 34 g (0.285 mol) of thionyl chloride was added dropwise for 0.5 h, and it was reacted for 4 h after the dropwise addition was completed. After the reaction is finished, cool and separate the liquids. Distill the lower layer solution at normal pressure first, then distill under reduced pressure to recover thionyl chloride and benzene. With the steaming of benzene, the raffinate in the distillation bottle solidifies into a viscous solid, that is, 4- Hydroxybenzoyl chloride. The product was 47% pure.

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PUM

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Abstract

The invention discloses a method for preparing 4-hydroxybenzoyl chloride. The method comprises the following steps: (1) adding 4-hydroxybenzoic acid, a benzene solvent and N,N-dimethyl formamide as an cosolvent into a container, heating up to 30-65 DEG C while stirring, slowly and dropwise adding thionyl chloride for 0.5 to 1 hour and reacting at 30 to 65 DEG C for 2 to 5 hour; (2) standing to demix the reaction solution; and (3) respectively recovering thionyl chloride, benzene and N,N-dimethyl formamide respectively by distilling and distilling under the reduced pressure, and concentrating the benzene layer solution to separate viscose solid (4-hydroxybenzoyl chloride). The method is simple and reliable, and by adopting the method, 4-hydroxybenzoyl chloride with high purity and high yield can be obtained without need of the reduced pressure distillation.

Description

technical field [0001] The present invention relates to a kind of preparation method of benzoyl chloride compound, more specifically relate to a kind of preparation method of the benzoyl chloride compound that is connected with strong electron donating group on the benzene ring, namely 4-hydroxybenzoyl chloride. Background technique [0002] 4-Hydroxybenzoyl chloride compound is an important chemical intermediate, widely used in medicine, pesticides and other aspects. Because the benzene ring is equipped with a very strong first-class positioning group hydroxyl group, it is difficult to prepare 4-hydroxybenzoyl chloride from 4-hydroxybenzoic acid as a raw material. At present, only Germany can prepare this product, but the yield is low. , According to literature reports, only about 15%, and the purity of the product is not high. In order to obtain 4-hydroxybenzoyl chloride of higher purity, the prior art adopts the method for underpressure distillation to steam the product,...

Claims

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Application Information

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IPC IPC(8): C07C65/03C07C51/60
Inventor 金东元
Owner SHANGHAI INST OF TECH
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