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The preparation method of ethyl 4-aminobenzoate powder

A technology of ethyl aminobenzoate and aminobenzoic acid, applied in the field of preparation of ethyl 4-aminobenzoate powder, can solve the problems of low production capacity, easy generation of dust, high energy consumption, etc., and achieve high production capacity and reduce pollution , the effect of low energy consumption

Active Publication Date: 2019-07-26
CHANGZHOU SUNLIGHT PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Existing method all is to adopt mechanical pulverization or jet pulverization to pulverize the 4-aminobenzoic acid ethyl ester that conventional production method obtains to obtain the 4-aminobenzoic acid ethyl ester of required particle size, and this method for preparing powder easily produces dust, Low production capacity and high energy consumption

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1）

[0020] The preparation method of the ethyl 4-aminobenzoate powder of the present embodiment is as follows:

[0021] ①Add 40g of 4-nitrobenzoic acid, 200mL of water, 0.5g of 4-dimethylaminopyridine and 0.6g of 3wt% palladium carbon catalyst into the autoclave, first replace it with nitrogen three times, then feed hydrogen and adjust the pressure to 0.8±0.1MPa, and at the same time control the temperature at 100±2°C, heat preservation and pressure to complete the reaction.

[0022] After the reaction, the catalyst was recovered by filtration, the filtrate was cooled, crystallized, filtered, and dried under vacuum at 80-85°C to obtain 32.0 g of 4-aminobenzoic acid with a yield of 97.5%, a melting point of 187.0-187.5°C, and a content of 99.9 % (permanent stop titration).

[0023] ②Add 200mL of ethanol to the reaction bottle and keep the temperature at 25±5℃, then add 27g of 98wt% concentrated sulfuric acid dropwise, and then add 30g of 4-aminobenzoic acid, heat to reflux and com...

Embodiment 2）

[0041] The preparation method of the ethyl 4-aminobenzoate powder of the present embodiment is as follows:

[0042] ①Add 60g of 4-nitrobenzoic acid, 300mL of water, 1.0g of 4-dimethylaminopyridine and 1.1g of 3wt% palladium carbon catalyst into the autoclave, first replace it with nitrogen three times, then feed hydrogen and adjust the pressure to 0.8±0.1MPa, and at the same time control the temperature at 100±2°C, heat preservation and pressure to complete the reaction.

[0043] After the reaction, the catalyst was recovered by filtration, the filtrate was cooled, crystallized, filtered, and dried under vacuum at 80-85°C to obtain 47.7g of 4-aminobenzoic acid with a yield of 96.9%, a melting point of 187.1-187.6°C, and a content of 100.2 % (permanent stop titration).

[0044] ②Add 260mL of ethanol to the reaction bottle and keep the temperature at 25±5℃, then add 38g of 98wt% concentrated sulfuric acid dropwise, and then add 45g of 4-aminobenzoic acid, heat to reflux and com...

Embodiment 3）

[0049] The preparation method of the ethyl 4-aminobenzoate powder of the present embodiment is as follows:

[0050]①Add 60g of 4-nitrobenzoic acid, 300mL of water, 1.0g of 4-dimethylaminopyridine and 1.1g of 3wt% palladium carbon catalyst into the autoclave, first replace it with nitrogen three times, then feed hydrogen and adjust the pressure to 0.8±0.1MPa, and at the same time control the temperature at 100±2°C, heat preservation and pressure to complete the reaction.

[0051] After the reaction, the catalyst was recovered by filtration, the filtrate was cooled, crystallized, filtered, and dried under vacuum at 80-85°C to obtain 47.7g of 4-aminobenzoic acid, the yield was 96.9%, the melting point was 186.9-187.5°C, and the content was 99.8 % (permanent stop titration).

[0052] ② Add 260mL of ethanol to the reaction bottle and keep the temperature at 25±5°C, then add 38g of 98wt% concentrated sulfuric acid dropwise, and then add 45g of 4-aminobenzoic acid, heat to reflux an...

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Abstract

The invention discloses a preparation method of a 4-ethyl aminobenzoate powder. The preparation method includes the steps of: 1) catalytically hydrogenating 4-nitrobenzoic acid to prepare 4-aminobenzoic acid; 2) esterifying the 4-aminobenzoic acid with ethanol to prepare a 4-ethyl aminobenzoate crude product; 3) performing ethanol recrystallization, in the presence of alkyl sulfonate, to the 4-ethyl aminobenzoate crude product to prepare the 4-ethyl aminobenzoate powder. In the method, a less amount of alkyl sulfonates, such as sodium dodecyl sulfate, is added during the ethanol recrystallization step, so that the crystallization process of the product is controlled well. The 4-ethyl aminobenzoate powder has small granularity and uniform granularity distribution, is high in quality, and can satisfy the high demand on granularity in the fields of medicines, materials and cosmetics.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and in particular relates to a preparation method of ethyl 4-aminobenzoate powder. Background technique [0002] Ethyl 4-aminobenzoate, also known as benzocaine, is mainly used in the production of medicine, plastics and coatings. In terms of medicine, ethyl 4-aminobenzoate is a non-water-soluble local anesthetic, which has good analgesic and antipruritic effects, and is mainly used for relieving pain and itching on ulcers, wounds and mucosal surfaces. Lubrication and pain relief for nasopharyngeal catheters and endoscopes. As a local anesthetic with strong ester solubility, ethyl 4-aminobenzoate is easy to combine with the lipid layer of the skin or mucous membrane, and it is difficult to enter the body to cause toxicity. In terms of materials, ethyl 4-aminobenzoate is a protective agent that blocks sunlight's ultraviolet rays and is added to plastics and paints. [0003] In order to e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C227/18C07C227/42C07C227/44C07C229/60
CPCC07C227/04C07C227/18C07C227/42C07C227/44C07C229/60
Inventor 胡国宜胡锦平吴建华张培峰奚小金
Owner CHANGZHOU SUNLIGHT PHARMA
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