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Process for preparing benzocaine through solvent-free hydrogenation

A benzocaine and solvent-free technology, which is applied in the chemical industry, can solve the problems of excessive waste water, yield impact, and no improvement involved, so as to reduce pollution, reduce the discharge of organic waste liquid, good reaction yield and product purity Effect

Active Publication Date: 2019-12-20
浙江优创材料科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese patent document CN105315168A discloses a green preparation process of N-(4-ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine intermediate (that is, benzocaine). The literature mainly focuses on the esterification reaction. Using the recovered concentrated sulfuric acid and ethanol as the reaction materials can not only reduce the production cost, but also obtain a higher yield of the esterification reaction, especially to avoid the generation of high-salt wastewater. Reduction of pollution to the environment, no improvements are involved in catalytic hydrogenation
Another patent document CN108314627A also discloses a green preparation process of benzocaine, which focuses on the green preparation process of benzocaine using a kind of water as a catalytic hydrogenation reaction of solvent, although no organic solvent is used as solvent, but There is still a lot of waste water generated during the reaction, and the amount of water will also have a greater impact on the yield

Method used

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  • Process for preparing benzocaine through solvent-free hydrogenation
  • Process for preparing benzocaine through solvent-free hydrogenation
  • Process for preparing benzocaine through solvent-free hydrogenation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Add 500g of ethyl p-nitrobenzoate into a 1L autoclave, control the temperature at 120°C, keep it warm for 1h, then add 5g of activated Raney nickel catalyst, replace it with nitrogen three times, then hydrogen three times, and then stir Pass hydrogen to 0.4MPa, and carry out the hydrogenation reaction at a temperature of 120°C. When the pressure no longer drops, after the hydrogenation reaction is completed, keep the temperature for 4 hours, and discharge the hydrogen gas to stop the reaction.

[0023] The GC analysis results of the sampling analysis showed that the purity of benzocaine was 99.98%, ethyl p-nitrobenzoate was not detected, and the rest were unknown components. Filter the material through a precision filter, press into 500g of water for crystallization, stir until the temperature reaches 25°C, centrifuge to obtain a wet product, and vacuum dry for 12 hours to obtain 418.8g of the final product with a yield of 98.99%.

Embodiment 2

[0025] Add 500g of ethyl p-nitrobenzoate into a 1L autoclave, control the temperature at 120°C, keep it warm for 1h, then add 7.5g of activated Raney nickel catalyst, replace it with nitrogen three times, then hydrogen three times, then stir Pass hydrogen down to 0.4MPa, and carry out the hydrogenation reaction at a temperature of 120°C. When the pressure no longer drops, after the hydrogenation reaction ends, keep the temperature for 4 hours, and discharge the hydrogen to stop the reaction.

[0026] The GC analysis results of the sampling analysis showed that the purity of benzocaine was 99.97%, ethyl p-nitrobenzoate was not detected, and the rest were unknown components. Filter the material through a precision filter, press into 500g of water for crystallization, stir until the temperature reaches 25°C, centrifuge to obtain a wet product, and vacuum dry for 12 hours to obtain 419.0g of the final product with a yield of 99.04%.

Embodiment 3

[0027] Embodiment 3,4 is the amplification experiment

[0028] Embodiment 3 (amplification experiment of embodiment 1)

[0029] To scale up the experiment, add 20kg of ethyl p-nitrobenzoate into a 50L autoclave, control the temperature at 120°C, keep it warm for 2 hours, then add 200g of activated Raney nickel catalyst, replace it with nitrogen three times, and then replace it with hydrogen three times. Then pass hydrogen to 0.4MPa under stirring, and carry out hydrogenation reaction at a temperature of 120 ° C. When the pressure no longer drops, after the hydrogenation reaction is completed, keep warm for 4 hours, and discharge hydrogen to stop the reaction.

[0030] The GC analysis results of the sampling analysis showed that the purity of benzocaine was 99.97%, ethyl p-nitrobenzoate was not detected, and the rest were unknown components. Filter the material through a precision filter, press into 20kg of water for crystallization, stir until the temperature reaches 25°C, ce...

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Abstract

The invention relates to a process for preparing benzocaine (ethyl p-aminobenzoate) through solvent-free hydrogenation, and belongs to the field of chemical engineering. The process comprises: (1) heating ethyl p-nitrobenzoate for more than 1 h at a temperature of more than 100 DEG C; (2) adding a catalyst and the ethyl p-nitrobenzoate treated in the step (1); and (3) in the absence of a solvent,introducing hydrogen until the reaction does not absorb hydrogen, and carrying out post-treatment to obtain the product.

Description

technical field [0001] The invention relates to a process for preparing benzocaine (ethyl p-aminobenzoate) by solvent-free hydrogenation, which belongs to the field of chemical industry. Background technique [0002] Benzocaine is another name for ethyl p-aminobenzoate. As an ultraviolet absorber, it is mainly used in sunscreen and tanning cosmetics. It is chemically stable to light and air, safe to the skin, and has The film-forming ability can effectively absorb U. V. The amount of ultraviolet rays in the 280-320μm medium-wave light area of ​​B area is usually about 4%. At the same time, it is a local anesthetic, which acts on the nerve tissue of the skin and mucous membranes, blocks the conduction of nerve impulses, temporarily loses various sensations, paralyzes the sensory nerve endings and produces analgesic and antipruritic effects. It can be used for wounds, ulcers and hemorrhoids. For itching and pain relief, use a concentration of 5% to 20%. It is also used as ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C227/04C07C229/60
CPCC07C227/04C07C229/60Y02P20/584
Inventor 茅月成吴元飞朱晓东
Owner 浙江优创材料科技股份有限公司
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