Preparation method of 3-cyano-pyridine N-oxide

By using silicomolybdic acid, phosphomolybdic acid or phosphotungstic acid catalysts and hydrogen peroxide oxidation in the industrial production of 3-cyanopyridine-N-oxide, the problem of excessive by-product nicotinamide-N-oxide is solved and achieved This method provides efficient and low-cost preparation of 3-cyano-N-oxide, improves the purity and yield of the product, and is suitable for industrial production.

CN103570617AActive Publication Date: 2014-02-12ZHEJIANG RONGKAI TECH DEV
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Patent Information

Application Number
CN201310569066.8
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2013-11-15
Publication Date
2014-02-12
Estimated Expiration
2033-11-15

AI Technical Summary

Technical Problem

The existing industrial production of 3-cyanopyridine-N-oxide contains a large amount of nicotinamide-N-oxide as a by-product, resulting in insufficient product purity and yield, and high catalyst costs, making it unsuitable for industrial production.

Method used

Add 3-cyanopyridine, catalyst, water and sulfuric acid to the reaction bottle. After the temperature rises, slowly add 30% hydrogen peroxide as the oxidant. Control the oxidation reaction temperature at 75-95°C. The dropping time is 12-18 hours. Use silicon molybdenum. Acid, phosphomolybdic acid or phosphotungstic acid is used as a catalyst, water is used as a solvent, and sulfuric acid is used as an auxiliary catalyst to achieve efficient preparation of 3-cyano-N-oxide.

Benefits of technology

It improves the purity and yield of 3-cyano-N-oxide, reduces the generation of nicotinamide-N-oxide, is suitable for industrial production, and improves the synthesis yield of the next chlorination reaction.

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Abstract

The invention provides a preparation method of 3-cyano-pyridine N-oxide. The preparation method comprises the following steps that 3-cyano-pyridine is put into a reaction bottle; 3-cyano-pyridine is heated in the presence of water as a solvent and sulfuric acid as a co-catalyst; then an oxidizing agent is dropwisely added into the reaction bottle; the mixture undergoes an oxidation reaction; the reaction product is cooled, stood and filtered; and the filter residues are dried. The preparation method realizes high-selectivity and high-efficiency preparation of the 3-cyano-pyridine N-oxide. The 3-cyano-pyridine N-oxide has low nicotinamido-N-oxide content so that a follow-up chlorination reaction is promoted and a 2-chloronicotinic acid synthesis yield is improved. The preparation method has a low cost, improves the oxidation product purity and yield and is suitable for industrial production.
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