Preparation method of 3-hydroxy-2-nitropyridine

By using potassium nitrate instead of traditional nitrating agent, potassium nitrate reacts with concentrated sulfuric acid to prepare 3-hydroxy-2-nitropyridine, which solves the problems of acid mist and pollution in traditional methods, achieves high purity and high yield preparation, and ensures Reflecting safety and environmental protection.

CN103992267AInactive Publication Date: 2014-08-20梁成
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Patent Information

Application Number
CN201410262177.9
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2014-06-13
Publication Date
2014-08-20
Estimated Expiration
Not applicable · inactive patent

AI Technical Summary

Technical Problem

The traditional method of preparing 3-hydroxy-2-nitropyridine uses concentrated sulfuric acid and concentrated nitric acid as nitrating agents, which results in the generation of acid mist and hydrogen chloride gas, causing environmental pollution and safety hazards, and the nitration yield is low.

Method used

Potassium nitrate is used to replace concentrated sulfuric acid and concentrated nitric acid. By reacting 3-hydroxypyridine with anhydrous KNO3 in concentrated sulfuric acid, raising the temperature and adjusting the pH value, high-purity 3-hydroxy-2-nitropyridine is obtained with almost no acid produced. fog and nitrogen oxides, significantly reducing oxidation side reactions and increasing nitrification yield.

Benefits of technology

This method is simple to operate, safe and reliable, almost does not pollute the environment, the nitration yield is greatly improved, and the obtained 3-hydroxy-2-nitropyridine is of high purity and is suitable for the next application.

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Abstract

The invention discloses a preparation method of 3-hydroxy-2-nitropyridine. The method comprises the following steps of dissolving 3-hydroxypyridine in concentrated sulfuric acid, slowly adding anhydrous KNO3 in batches, heating for complete reaction to obtain a mixture, slowly pouring the mixture into water, adjusting the pH value of a solution to be 4.5-7.5 by using solid NaHCO3, standing for the whole night, filtering, and drying to obtain 3-hydroxy-2-nitropyridine. According to the method, KNO3 is adopted for replacing concentrated nitric acid and concentrated sulfuric acid to form a nitrating agent; the method has the advantages that KNO3 can be dried in vacuum to obtain anhydrous KNO3, and anhydrous KNO3 is stable in properties and easy to store; no acid mist is generated, and anhydrous KNO3 can be conveniently added into a reactor; high-purity nitric acid can be gradually generated under the heating condition after anhydrous KNO3 is mixed with concentrated sulfuric acid, nitration reaction can be stably performed all the time, an environment is basically not polluted, oxidation side-reactions are remarkably reduced, the reaction is safe and controllable, and the nitration yield is greatly increased.
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