Preparation method of 3-cyanopyridine oxynitride

Abstract

The invention discloses a preparation method of 3-cyanopyridine oxynitride. The preparation method is characterized by comprising the following steps of: melting 500kg of 3-cyanopyridine, adding the molten 3-cyanopyridine into an enamel reaction kettle, adding 10kg of concentrated sulfuric acid and 8kg of molybdenum oxide into the reaction kettle, stirring the mixture, slowly heating to 65 DEG C, beginning to dropwise add hydrogen peroxide, controlling the dropping speed at about 200kg / h, after the dropwise adding operation is ended, continuing to react at the temperature of 65-68 DEG C for 7-8h, sampling, detecting the sample by using gas chromatography, and ending the heat preservation when the content of the 3-cyanopyridine is lower than or equal to 1.0%; and adjusting the pH value of the reaction liquid to 9.5-10.5 by using potassium carbonate, crystallizing, cooling the crystal to be below 5 DEG C, centrifuging, and drying the crystal at the temperature of 80-90 DEG C to obtain the 3-cyanopyridine oxynitride, wherein the water content of the 3-cyanopyridine oxynitride is smaller than or equal to 1.0%. Compared with the prior art, the preparation method has the advantage that the production cost is greatly reduced, so that the economic benefit and market competitiveness of an enterprise are increased.

Description

technical field

[0001] The invention relates to a preparation method of a chemical intermediate, in particular to a preparation method of 3-cyanopyridine nitrogen oxide. Background technique

[0002] 3-cyanopyridine nitrogen oxide is the main intermediate for the production of nicotinic acid and nicotinamide, and its production cost determines the final cost of nicotinic acid and nicotinamide, which in turn determines the economic benefits of the enterprise. The preparation method disclosed in the current literature is to oxidize 3-cyanopyridine with hydrogen peroxide under the action of sulfuric acid and catalyst sodium tungstate, the molar ratio of hydrogen peroxide to 3-cyanopyridine is 1:4, and the reaction temperature is 90°. The reaction time was 20 hours, and the yield was only 94% (based on 3-cyanopyridine). Because this method uses expensive sodium tungstate (160-180 yuan / kg) as a catalyst, the reaction temperature is high, the reaction time is long, and the yield ...

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