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Method for cyclic application of byproduct and solvent in metronidazole production

A technology of solvent circulation and metronidazole, which is applied in organic chemistry and other fields, can solve the problem that the utilization rate of ethylene oxide does not exceed 25%.

Inactive Publication Date: 2018-06-08
HUANGGANG NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the above-mentioned three patents have increased the chance of contact reaction between ethylene oxide and materials to varying degrees, the utilization rate of ethylene oxide is still no more than 25%.

Method used

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  • Method for cyclic application of byproduct and solvent in metronidazole production

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Step 1): Add 2-methyl-5-nitroimidazole into the reaction kettle, add dropwise formic acid solvent with a concentration of 85% to dissolve 2-methyl-5-nitroimidazole, and gradually add epoxy at 30-40°C Ethane, add sulfuric acid with a concentration of 98% at the same time, raise the temperature to 95°C, and react for 1h to obtain a hydroxylated solution;

[0028] Step 2): adding methanol, controlling the temperature within the range of 10°C higher than the boiling point of methyl formate, carrying out esterification, distillation, and condensing the evaporated steam to obtain methyl formate;

[0029] Step 3): the temperature rises to a range below 10°C higher than the boiling point of methanol, and distills to obtain methanol;

[0030] Step 4): After the hydroxylation solution is cooled to 10°C, adjust the pH to 10 with sodium hydroxide solution, leave to cool, crystallize, and filter to obtain metronidazole;

[0031] Step 5): evaporating and concentrating the filtrate o...

Embodiment 2

[0038] Step 1): Add 2-methyl-5-nitroimidazole into the reaction kettle, add dropwise formic acid solvent with a concentration of 95% to dissolve 2-methyl-5-nitroimidazole, and gradually add epoxy at 30-40°C Ethane, add sulfuric acid with a concentration of 98% at the same time, raise the temperature to 95°C, and react for 1h to obtain a hydroxylated solution;

[0039] Step 2): adding methanol, controlling the temperature within the range of 10°C higher than the boiling point of methyl formate, carrying out esterification, distillation, and condensing the evaporated steam to obtain methyl formate;

[0040] Step 3): the temperature rises to a range below 10°C higher than the boiling point of methanol, and distills to obtain methanol;

[0041] Step 4): After the hydroxylation solution is cooled to 10°C, adjust the pH to 10 with sodium hydroxide solution, leave to cool, crystallize, and filter to obtain metronidazole;

[0042]Step 5): evaporating and concentrating the filtrate ob...

Embodiment 3

[0049] Step 1): Add 2-methyl-5-nitroimidazole into the reaction kettle, add dropwise formic acid solvent with a concentration of 85% to dissolve 2-methyl-5-nitroimidazole, and gradually add epoxy at 30-40°C Ethane, while adding fuming sulfuric acid with a concentration of 105%, heating up to 95°C, and reacting for 1 hour to obtain a hydroxylated solution;

[0050] Step 2): adding methanol, controlling the temperature within the range of 10°C higher than the boiling point of methyl formate, carrying out esterification, distillation, and condensing the evaporated steam to obtain methyl formate;

[0051] Step 3): the temperature rises to a range below 10°C higher than the boiling point of methanol, and distills to obtain methanol;

[0052] Step 4): After the hydroxylation solution is cooled to 10°C, adjust the pH to 10 with sodium hydroxide solution, leave to cool, crystallize, and filter to obtain metronidazole;

[0053] Step 5): evaporating and concentrating the filtrate obtai...

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Abstract

The invention provides a method for cyclic application of a byproduct and a solvent in metronidazole production. The method comprises the steps: mixing and stirring formate corresponding to low-carbonalcohol separated by distillation and a distillation residue, carrying out a transesterification reaction on formate corresponding to low-carbon alcohol and ethylene glycol in the distillation residue to obtain ethylene glycol formate and low-carbon alcohol, after the transesterification reaction is balanced, applying strong heat to rapidly raise the temperature to a boiling point of low-carbon alcohol, rapidly distilling formate corresponding to unconverted low-carbon alcohol and low-carbon alcohol serving as a converted product, and separating formate corresponding to low-carbon alcohol toobtain the distillation residue at the same time; and repeatedly operating the steps until the monoesterification rate of ethylene glycol in the distillation residue is found to reach 95% by gas chromatographic detection so as to finally obtain ethylene glycol formate and the distillation residue of unconverted ethylene glycol. The produced ethylene glycol formate serves as a solvent to be added in the next reaction step, so that the usage amount of a formic acid solvent is reduced, meanwhile, the utilization ratio of epoxyethane is increased, and the production cost is reduced.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a method for recycling by-products and solvents in the production of metronidazole. Background technique [0002] Metronidazole is white or yellowish crystal or crystalline powder, used for the treatment of intestinal and parenteral amoebiasis (such as amebic liver abscess, pleural amoebiasis, etc.). It can also be used to treat vaginal trichomoniasis, cylindrosis, skin leishmaniasis, and guinea worm infection. At present, it is also widely used in the treatment of anaerobic infection, and is regarded as the drug of choice for anti-anaerobic bacteria by the World Health Organization (WHO). [0003] The current process of synthesizing metronidazole is to dissolve 2-methyl-5-nitroimidazole in formic acid, add ethylene oxide successively at 30-40°C, and add sulfuric acid in the middle of the addition. After addition, react for 1h to obtain hydroxylated solution. Use sodium hydrox...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D233/94
CPCC07D233/94
Inventor 曾舟华曾彩红刘晓晖冉敬文黄林勇杨水彬
Owner HUANGGANG NORMAL UNIV