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Preparation method of p-nitrobenzyl alcohol

A technology of p-nitrobenzyl alcohol and mass ratio, which is applied in the preparation of organic compounds, chemical instruments and methods, organic chemistry, etc., can solve the problems of inability to obtain high-purity p-nitrobenzyl alcohol products, pungent odor, and hazards to operators Health and other issues, to save the centrifuge section, improve yield and purity, and reduce environmental pollution

Inactive Publication Date: 2018-06-08
GUANNAN YISITE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are following defects in the process of above-mentioned freeze crystallization and centrifugation: 1, need to use dichloroethane as organic solvent, dichloroethane has pungent smell, seriously endangers the health of operator; 2, because dichloroethane The addition of nitrobenzyl alcohol makes the introduction of higher content of chloride ions in the p-nitrobenzyl alcohol product, and it is impossible to obtain high-purity p-nitrobenzyl alcohol product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0016] Bromination: put 400kg of p-nitrotoluene, 1200kg of tap water and 240kg of bromine into the reaction pot, seal the lid of the pot, heat up the jacket with steam, raise the temperature to 50°C, turn off the steam, add 10kg of initiator, and initiate the reaction , the temperature is controlled at 80~85°C, when the red color in the pot fades, start to add 230 kg of hydrogen peroxide dropwise, control the dropwise addition within 4 hours, add the initiator according to the reaction situation, keep the temperature for 3 hours after the hydrogen peroxide drops, finish the reaction, and get the bromide;

[0017] Hydrolysis: pump the bromide into the hydrolysis pot, add 300kg of soda ash, add 1500kg of tap water, close the lid of the pot, heat up to 90~100℃ through the jacket, keep it warm for 6~8h, and get the hydrolyzate;

[0018] Separation and purification of alcohol and water: after the heat preservation, pump the hydrolyzate into the alcohol water pot, add 1000kg of tap w...

Embodiment approach 2

[0021] Bromination: Put 400kg of p-nitrotoluene, 1200kg of tap water and 260kg of bromine into the reaction pot, seal the lid of the pot, heat up the jacket with steam, raise the temperature to 50°C, turn off the steam, add 10kg of initiator, and initiate the reaction , the temperature is controlled at 80~85°C, when the red color in the pot fades, start to add 250 kg of hydrogen peroxide dropwise, control the dropwise addition within 4 hours, add the initiator according to the reaction situation, keep the temperature for 3 hours after the hydrogen peroxide drops, finish the reaction, and get the bromide;

[0022] Hydrolysis: pump the bromide into the hydrolysis pot, add 320kg of soda ash, add 1500kg of tap water, close the lid of the pot, heat up to 75~80°C with steam in the jacket, keep it warm for 6~8h, and get the hydrolyzate;

[0023] Separation and purification of alcohol and water: after the heat preservation, pump the hydrolyzate into the alcohol water pot, add 1000kg of...

Embodiment approach 3

[0026] Bromination: Put 400kg of p-nitrotoluene, 1200kg of tap water and 230kg of bromine into the reaction pot, seal the lid of the pot, heat up the jacket with steam, raise the temperature to 50°C, turn off the steam, add 10kg of initiator, and initiate the reaction , the temperature is controlled at 80~85°C, when the red color in the pot fades, start to add 220kg of hydrogen peroxide dropwise, control the dropwise addition within 4 hours, add the initiator according to the reaction situation, keep the temperature for 3 hours after the hydrogen peroxide drops, finish the reaction, and get the bromide;

[0027] Hydrolysis: pump the bromide into the hydrolysis pot, add 360kg of soda ash, add 1500kg of tap water, close the lid of the pot, heat up to 75~80°C through the jacket, keep it warm for 6~8h, and get the hydrolyzate;

[0028] Separation and purification of alcohol and water: after the heat preservation, pump the hydrolyzate into the alcohol water pot, add 1000kg of tap wa...

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Abstract

The invention relates to the field of medical intermediates, and discloses a preparation method of p-nitrobenzyl alcohol. The method comprises the steps of dissolving p-nitrotoluene and bromine into water, adding the mixed solution into a reaction kettle, adding an initiator at the temperature of 45-55 DEG C into the reaction kettle for an initiation reaction until red fades; dropwise adding hydrogen peroxide and adding the initiator as appropriate; after addition is finished, carrying out a reaction at the temperature of 80-85 DEG C until red fades so as to obtain bromides; adding sodium carbonate and water, and carrying out heat preservation for 6-8h at the temperature of 90-100 DEG C to obtain hydrolysate; adding water and methanol, carrying out heat preservation for 1h at the temperature of 60-65 DEG C, separating out an oil layer, cooling and crystallizing, and centrifuging when the temperature drops to 0 DEG C so as to obtain a crude p-nitrobenzyl alcohol product; adding methylbenzene, carrying out heat preservation for 30min at the temperature of 70-75 DEG C, carrying out filter pressing, cooling, and crystallizing to obtain the p-nitrobenzyl alcohol product. A dichloroethane organic solvent does not need to be used in the method, so that the method is harmless to an operator, and the purity of the product is higher.

Description

technical field [0001] The invention relates to the field of pharmaceutical intermediates, in particular to a preparation method of p-nitrobenzyl alcohol. Background technique [0002] p-Nitrobenzyl alcohol is a very important intermediate in the pharmaceutical industry. The current preparation method is to first mix p-nitrotoluene and bromine for bromination reaction to generate p-nitrobenzyl bromide and p-nitrobenzyl bromide. Then it is hydrolyzed after freeze crystallization and centrifugation, and the p-nitro-benzyl bromide is hydrolyzed into p-nitrobenzyl alcohol. There are following defects in the process of above-mentioned freeze crystallization and centrifugation: 1, need to use dichloroethane as organic solvent, dichloroethane has pungent smell, seriously endangers the health of operator; 2, because dichloroethane The addition of makes in p-nitrobenzyl alcohol product, has introduced the chloride ion of higher content, can't obtain the p-nitrobenzyl alcohol product...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/12C07C205/37
CPCC07C201/12C07C205/37C07C205/22C07C205/12
Inventor 张守平陈卫东
Owner GUANNAN YISITE CHEM
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