A kind of 2-methyl-5 nitroimidazole production technology

A technology of nitroimidazole and production process, applied in the field of 2-methyl-5 nitroimidazole production process, can solve the problems of nitrogen dioxide emission, inconvenient material management, low product yield and the like, and achieves reduction of production cost, Facilitate material management and stable production system

Active Publication Date: 2020-07-10
HUBEI HONGYUAN PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the direct reaction with mixed acid, a large amount of nitrogen dioxide will emerge, and the product yield is low
In the prior art, a mixture of urea and ammonium sulfate is added as a catalyst and stabilizer for the reaction, a mixture of nitric acid, urea and ammonium sulfate is added to 2-methylimidazole, then concentrated sulfuric acid is added dropwise at elevated temperature, and then nitric acid and sulfuric acid are added to form The mixed acid, finally adjust pH with sodium hydroxide to neutralize the nitration solution, obtain 2-methyl-5 nitroimidazole after filtration, can eliminate smog and improve product yield, there are following disadvantages in the actual operation process of this method: 1 ) Use sodium hydroxide for neutralization, because its alkalinity is too strong, the neutralization index is difficult to accurately control, and the neutralization end point is: pH=4.0-5.0, which is not suitable for large-scale production; 2) Use a mixture of urea and ammonium sulfate as Catalyst and stabilizer for the reaction, the production cost is high, and it is not convenient for material management in industrialization; 3) Urea is easy to decompose during the reaction process and cannot be recycled reasonably

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0021] The present embodiment provides a kind of 2-methyl-5 nitroimidazole production process, comprises the following steps:

[0022] (1) Nitrification reaction: Add 855kg of 98% sulfuric acid to the reaction kettle, when the temperature is 60°C, add 1075kg of ammonium sulfate, add 2-methylimidazole in three times, and put 2-methylimidazole 15kg when the temperature reaches 80°C Add 15 packs of 2-methylimidazole at a temperature of 85°C, and add 11 packs of 2-methylimidazole at a controlled temperature of 130°C. 20±0.15kg per package, 820±6kg in total, when the temperature reaches 140°C, add 845kg of 87% nitric acid at a flow rate of 235kg / H, keep warm for 150 minutes (monitor the temperature once every 30min), maintain the temperature at 140°C, and cool down to 140°C When the temperature is below ℃, prepare to unload. Before unloading, check whether the inside of the neutralization kettle is clean, then add 2000kg of drinking water, cover the manhole cover, and transfer the ...

Embodiment 2

[0027] The present embodiment provides a kind of 2-methyl-5 nitroimidazole production process, comprises the following steps:

[0028] (1) Nitrification reaction: add 858kg of 98% sulfuric acid to the reaction kettle, when the temperature is 65°C, add 1078kg of ammonium sulfate, add 2-methylimidazole in three times, and put 2-methylimidazole 15kg when the temperature reaches 90°C 15 packs of 2-methylimidazole were added at a controlled temperature of 95°C, and 11 packs of 2-methylimidazole were added at a controlled temperature of 135°C. 20±0.15kg per package, 820±6kg in total, when the temperature reaches 142°C, add 848kg of 88% nitric acid at a flow rate of 238kg / H, keep warm for 158 minutes (monitor the temperature once every 30min), maintain the temperature at 143°C, and cool down to 140 When the temperature is below ℃, prepare to unload. Before unloading, check whether the inside of the neutralization kettle is clean, then add 2000kg of drinking water, cover the manhole c...

Embodiment 3

[0033] The present embodiment provides a kind of 2-methyl-5 nitroimidazole production process, comprises the following steps:

[0034](1) Nitrification reaction: add 860kg of 98% sulfuric acid to the reaction kettle, when the temperature is 70°C, add 1080kg of ammonium sulfate, add 2-methylimidazole in three times, when the temperature reaches 100°C, put 2-methylimidazole 15 Add 15 bags of 2-methylimidazole at a temperature of 105°C, and add 11 bags of 2-methylimidazole at a temperature of 110°C. 20±0.15kg per package, 820±6kg in total, when the temperature reaches 145°C, add 850kg of 89% nitric acid at a flow rate of 240kg / H, keep warm for 160 minutes (monitor the temperature once every 30min), maintain the temperature at 148°C, and cool down to 140 When the temperature is below ℃, prepare to unload. Before unloading, check whether the inside of the neutralization kettle is clean, then add 2000kg of drinking water, cover the manhole cover, and transfer the material liquid in ...

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PUM

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Abstract

The invention discloses a process for producing 2-methyl-5-nitroimidazole. The process comprises the following steps: (1) a nitration reaction, (2) neutralization and centrifugation, and (3) drying and packaging, wherein the step (2) further comprises a process for recovering ammonium sulfate from wastewater, and the process comprises the steps of adding the wastewater into a tri-effect evaporating crystallizer for mother liquor concentrating, carrying out crystallization to obtain ammonium sulfate, separating out ammonium sulfate crystals through a horizontal type spiral centrifuge, and carrying out drying by an air-flow dryer, thereby obtaining finished ammonium sulfate. According to the process, ammonia water is used for neutralizing a nitration solution, and a neutralization index is easy to accurately control, so that the process is more applicable to large-scale production; single ammonium sulfate is adopted as a catalyzing and stabilizing agent of reaction, the consumption of main materials is not affected, urea is not added, and the production cost is lower; and the single ammonium sulfate is used, thus, the recovery of ammonium sulfate from the wastewater is more facilitated, the product yield reaches 91.2% or more, and the product content reaches 99.7% or more.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a production process of 2-methyl-5-nitroimidazole. Background technique [0002] 2-Methyl-5-nitroimidazole is mainly used in organic synthesis in industry. It is an important intermediate for the synthesis of pharmaceutical raw materials metronidazole, secnidazole, and veterinary drug damexol. 2-methylimidazole is mostly used in industry As raw material, in concentrated sulfuric acid medium, concentrated nitric acid is added dropwise at high temperature for nitration reaction. Due to directly reacting with mixed acid, a large amount of nitrogen dioxide will come out, and the product yield is low. In the prior art, a mixture of urea and ammonium sulfate is added as a catalyst and stabilizer for the reaction, a mixture of nitric acid, urea and ammonium sulfate is added to 2-methylimidazole, then concentrated sulfuric acid is added dropwise at elevated temperature, and th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D233/92
CPCC07D233/92
Inventor 方耀喻莎莎陈申丰光俊童武晏浩哲黄佐
Owner HUBEI HONGYUAN PHARMA
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