A kind of synthetic method of 6-hydroxy-5-nitronicotinic acid and its separation and purification method

A technology for the synthesis of nitronicotinic acid, which is applied in the direction of organic chemistry, can solve the problems of difficult separation and purification, low yield, and many by-products in the reaction of picolinic acid compounds, and achieve the effect of increasing conversion rate and promoting conversion

CN104370807BActive Publication Date: 2016-10-05ANHUI XINGYU CHEM
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2016-10-05

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Abstract

The invention discloses a synthetic method and a separation purification method of 6-hydroxyl-5-nitro niacin and belongs to the field of fine chemical engineering. According to the method, 6-hydroxyl niacin is used as a raw material and is subjected to pre-nitration reaction under the action of concentrated sulfuric acid, concentrated nitric acid and a catalyst ammonium bisulfate, nitration reaction, crystal separation purification and the like to obtain highly purified 6- hydroxyl-5-nitro niacin to meet purity requirements on midbody by pharmaceutical synthetic fields. The synthetic method has the advantages of being simple in synthetic process, mild in condition, high in yield, high in purity of obtained product, easy to operate and the like and is suitable for industrial production.
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Description

Technical field

[0001] The invention belongs to the field of fine chemicals, and specifically relates to a method for synthesizing chemical intermediates, and more specifically, to a method for synthesizing 6-hydroxy-5-nitronicotinic acid and a method for separation and purification thereof. Background technique

[0002] Picolinic acid compounds are important fine chemical intermediates and are widely used in the fields of medicine and pesticides. Due to the reaction characteristics of hydroxyl and carboxyl groups, picolinic acid compounds containing hydroxyl and nitro groups are widely used in the fields of fine chemicals, pharmaceutical synthesis, pesticides, functional material preparation, and dye intermediates. The general method for synthesizing this type of compound is mainly to use nitration reaction to introduce a nitro group on the pyridine heterocycle. The common method is to nitrate with nitric acid in concentrated sulfuric acid, but the main obtained is the pyridine ...

Examples

Embodiment 1

[0034] A method for synthesizing 6-hydroxy-5-nitronicotinic acid, the steps are:

[0035] (a) Add concentrated sulfuric acid and concentrated nitric acid to the reaction flask in sequence and stir evenly to obtain reaction solution A. The molar ratio of concentrated sulfuric acid to concentrated nitric acid is 1:6, and the mass fraction of concentrated sulfuric acid used is 68%. The mass score is 86%;

[0036] (b) Mixing the raw material 6-hydroxynicotinic acid and the catalyst ammonium bisulfate according to a molar ratio of 50:1 to obtain reaction raw material B;

[0037] (c) Under stirring conditions, add the reaction material B obtained in step (b) to the reaction solution A obtained in step (a), and then heat to 60°C for a pre-nitrification reaction for 4 hours, wherein the HNO in the reaction solution A 3 The molar ratio with 6-hydroxynicotinic acid in the reaction raw material B is 1.5:1;

[0038] (d) Mix concentrated sulfuric acid and concentrated nitric acid (the mass fractio...

Embodiment 2

[0046] A method for synthesizing 6-hydroxy-5-nitronicotinic acid, the steps are:

[0047] (a) Add concentrated sulfuric acid and concentrated nitric acid to the reaction flask in sequence and stir evenly to obtain reaction solution A. The molar ratio of concentrated sulfuric acid to concentrated nitric acid is 1:5, and the mass fraction of concentrated sulfuric acid used is 68%. The mass score is 86%;

[0048] (b) Mixing the raw material 6-hydroxynicotinic acid and the catalyst ammonium bisulfate at a molar ratio of 60:1 to obtain reaction raw material B;

[0049] (c) Under stirring conditions, add the reaction material B obtained in step (b) to the reaction solution A obtained in step (a), and then heat to 50°C for a pre-nitrification reaction for 5 hours, wherein the HNO in the reaction solution A 3 The molar ratio with 6-hydroxynicotinic acid in the reaction raw material B is 1.0:1;

[0050] (d) Mix the concentrated sulfuric acid and concentrated nitric acid (the mass fraction of c...

Embodiment 3

[0058] A method for synthesizing 6-hydroxy-5-nitronicotinic acid, the steps are:

[0059] (a) Add concentrated sulfuric acid and concentrated nitric acid to the reaction flask in sequence and stir evenly to obtain reaction solution A. The molar ratio of concentrated sulfuric acid to concentrated nitric acid is 1:7, and the mass fraction of concentrated sulfuric acid used is 68%. The mass score is 86%;

[0060] (b) Mixing the raw material 6-hydroxynicotinic acid and the catalyst ammonium bisulfate at a molar ratio of 70:1 to obtain reaction raw material B;

[0061] (c) Under stirring conditions, add the reaction material B obtained in step (b) to the reaction solution A obtained in step (a), and then heat to 65° C. for pre-nitration reaction for 4.5 hours, wherein the reaction solution A in HNO 3 The molar ratio with 6-hydroxynicotinic acid in the reaction raw material B is 1.3:1;

[0062] (d) Mix concentrated sulfuric acid and concentrated nitric acid (the mass fraction of concentrat...