Application and preparation of 5-aminoisophthalic acid_Kain Industrial Additive

Background and overview^[1][2]

5-Amino-isophthalic acid is a widely used fine chemical product. It is insoluble in water and soluble in methanol, ethanol and acetone. It is mainly used as a pharmaceutical intermediate and can be used to prepare 5-hydroxypropionylamino-2 , 4,6-triiodoisopeptide acid-bis(1,3-dihydroxyisopropylamide) and other nonionic iodinated X-ray contrast agents, which have good water solubility, low osmotic pressure, and are easy to use. It has low chemical toxicity and side effects and a wide range of uses. It has good market potential internationally.

Preparation^[1]

Method 1,

(1) After ultrasonic pretreatment with acetone, ethanol and distilled water, nickel foam with a pore diameter of 0.2mm, a pore density of 110PPI, and a porosity of ≥95% is dried in a vacuum, placed in a tube furnace, and placed in an argon atmosphere. The temperature was raised to 600°C at 5°C, and acetylene gas was introduced to react for 1 hour. After the reaction was completed, the temperature was lowered to room temperature in an argon atmosphere to obtain a nickel foam/carbon nanotube magnetic catalyst. Among them, the nickel foam/carbon nanotube magnetic catalyst was The content of medium carbon nanotubes is 0.5wt%.

(2) 5-Nitro-isotitanic acid is fully dissolved in water, transferred to the reaction kettle, ammonia is added to adjust the pH of the system to 9, hydrogen gas is introduced at a flow rate of 25mL/min, and nickel foam/carbon nanotubes are added Magnetic catalyst, react at a constant temperature of 90°C for 100 minutes to obtain a 5-amino-isophthalic acid solution.

(3) After recovering the 5-amino-isophthalic acid solution using a magnet catalyst, filter and recover the mother liquor, add hydrochloric acid to acidify, lower to room temperature, recrystallize, and dry to obtain 5-amino-isophthalic acid.

Method 2,

(1) Add 400g of water and 60g of sodium carbonate to a 1000ml three-necked flask, start stirring, heat to dissolve, then add 100g of 5-nitroisophthalic acid (I) to completely dissolve;

(2) Under stirring, add the pre-prepared 20% sodium disulfide aqueous solution dropwise to the solution obtained in (1), control the temperature to 90-98°C, complete the addition in about half an hour, and reflux for 2.5 hours. Hot filter and collect the filtrate, in which the ratio of 5-nitroisophthalic acid to sodium disulfide is 1:0.6;

(3) Add concentrated hydrochloric acid to the filtrate obtained in (2) to acidify the pH to 3~3.5, cool and filter, then wash with cold water and dry to obtain 83.2g of 5-aminoisophthalic acid (II) , yield 97%, purity 99.5%, melting point >300°C.

Apply^[3]

The complexes formed by the transition metal Ni, 5-aminoisophthalic acid and 4, 4’-bipyridine have rich and diverse structures, which are of great research significance for the design and synthesis of complexes with target structures. CN201811303808.1 discloses a 5-aminoisophthalate nickel complex and a preparation method. The nickel 5-aminoisophthalate complex belongs to the monoclinic crystal system with a space group of 2/c. In this complex, the amino and carboxyl groups on 5-aminoisophthalic acid coordinate with the metal ion Co(II) ions in the form of monodentate or bidentate chelates, and 4,4′-bipyridine forms a bidentate bridge. It is coordinated with the metal ion Cd(II) ion in the form of a link, and the multidentate bridge of 5-aminoisophthalic acid and 4,4′-bipyridine with the central Co(II) ion constitutes the complex. Three-dimensional network space structure. The present invention uses 5-aminoisophthalic acid and 4,4′-bipyridyl as ligands and nickel sulfate hexahydrate to obtain a nickel complex through a hydrothermal method. It has the advantages of simple process, low cost, good repeatability, etc., and is a synthetic method. Transition metal complexes provide a certain basis.

Main reference materials

[1] [Chinese invention] CN201711246069.2 A production method of high-purity, efficient and high-yield 5-amino-isophthalic acid

[2] CN200810020399.4 Method for preparing 5-aminoisophthalic acid from 5-nitroisophthalic acid

[3] CN201811303808.15-Nickel aminoisophthalate complex and preparation method