Uses of pyridine-2,6-dicarboxylic acid_Industrial additives

Background and overview of the use of pyridine-2,6-dicarboxylic acid

Pyridine-2,6-dicarboxylic acid is an important pharmaceutical synthesis intermediate with many uses. widely. Pyridine-2,6-dicarboxylic acid naturally exists in bacterial spores, but its content is too small to meet demand and it is difficult to extract. It is not conducive to industrial production and application. The earliest report of artificial synthesis was in 1935. ALVIN.W.Singer and S.M.MCELVAIN of the University of Wisconsin used potassium permanganate to oxidize 2,6-dimethylpyridine in water as a solvent. The yield is 64%. Industrially, it is generally prepared by oxidizing 2,6-lutidine.

Pyridine-2,6-dicarboxylic acid preparation

Add 1000ml with thermometer Put 500ml of water, 2.0g of initiator ammonium persulfate, 1.0g of catalyst CuTPP, and 100g of raw material 2,6-dimethylpyridine into a three-neck flask. Start stirring, add air (until the reaction is completed), and heat to 80°C. Control the temperature at 80°C. After 3 hours of reaction, HPLC detects the conversion rate: 98.0%. Stop venting the air, filter and recover the catalyst. Add 15% mass percent sodium hydroxide solution dropwise to the filtrate to adjust the pH to 9, and let stand for separation. The lower water layer was acidified with hydrochloric acid with a mass percentage concentration of 15%, the pH was adjusted to 5, the precipitate was precipitated, filtered, and the filter cake was dried under reduced pressure at room temperature to obtain 150.3g of the product. Molar yield: 96.4%. After HPLC testing, the product purity was 99.84%.

Uses and applications of pyridine-2,6-dicarboxylic acid

Pyridine-2,6-dicarboxylic acid can be used to synthesize 2,6-diacetyl pyridine, 2,6-diamino-4-chloropyridine, (6-methoxyformamido-4-chloropyridin-2-yl)carbamate methyl ester, 6-aminomethylpyridine-2-carboxylic acid, 4-Chloropyridine-2,6-dicarboxylic acid hydrazide, 4-chloropyridine-2,6-dicarboxylic acid methyl ester, 6-aminoethylpyridine-2-carboxylic acid hydrazide, pyridine-2.6-dicarboxylic acid dicarboxylic acid hydrazide Methyl ester, 6-chloromethylpyridine-3-carboxylic acid ethyl ester, 6-hydroxymethylpyridine-2-carboxylic acid ethyl ester, 4-chloropyridine-2,6-dicarboxylic acid, 2,6-pyridine aluminum magnesium carbonate dimethylpyridinium dicarboxylate, N-methyl-pyridine-2,6-dicarboxylate, and then further synthesize metal ligand compounds, functional materials, pharmaceutical intermediates, etc.

Application 1. CN202010753097.9 discloses a vanadium pyridine catalyst for catalytic oxidation to prepare 2,5-dichlorophenol and its synthesis method and application. The catalyst is Py-V with the following structural formula The complex is prepared by dissolving pyridine-2,6-dicarboxylic acid in methanol, adding vanadyl acetylacetonate, and then going through steps such as reflux, filtration, washing, and pyridone drying. The operating steps of this method are simple and easy to control. The yield is over 60% in terms of vanadium, and the entire synthesis process is short and is suitable for industrial production. In the process of catalytically oxidizing 1,4-dichlorobenzene to prepare 2,5-dichlorophenol, using this Py-V complex as a catalyst can effectively inhibit the excessive production of 2,5-dichlorophenol while improving the catalytic efficiency. Oxidation and over-oxidation products can be controlled below 10%, the selectivity of 2,5-dichlorophenol reaches more than 90%, and the oxidation reaction efficiency and yield are significantly improved.

Application 2. CN201811320241.9 specifically relates to a polyester resin for low-gloss TGIC system powder coatings, the preparation method of the above-mentioned polyester resin, and the application of the polyester resin. The polyester resin of the present invention mainly includes isophthalic acid, pyridine-2,6-dicarboxylic acid, 6-acetylaminocaproic acid, 3-hydroxy-4-aminobutyric acid, polyethylene glycol diglycidyl ether, new Pentylene glycol, 2,4,6-trihydroxybenzoic acid, N-hydroxyethylethylenediaminetriacetic acid, esterification reaction catalyst, antioxidant. The polyester resin molecules prepared by the method of the present invention simultaneously contain active amine groups, hydroxyl groups and carboxyl groups. The difference in curing reaction rate between these three groups and the epoxy group in the TGIC molecule can be used to prepare low-density polymers. Glossy powder coating (glossiness <20%), the coating film performance can fully meet the requirements of powder coating.

References

[1]CN201310472482.6 Method for preparing pyridine-2,6-dicarboxylic acid by liquid phase catalytic oxidation

[2]CN202010753097. 9 A vanadium pyridine catalyst for catalytic oxidation to prepare 2,5-dichlorophenol and its synthesis method and application

[3]CN201811320241.9 Polyester resin for low-gloss TGIC system powder coating and its preparation method and Application