Preparation of 3-nitrophthalic acid_Kain Industrial Additive

Background and overview^[1]

3-Nitrophthalic acid (CASRegistryNO.603-11-2), also known as 3-nitro-1,2-benzenedicarboxylic acid, 3-nitrophthalic acid, m-nitrophthalic acid, Appearance is white to off-white crystalline powder, non-flammable, inactive, generally very stable, with a melting point of 210-216°C. Soluble in water, alcohol, slightly soluble in ether, it is an important intermediate in pesticides, pigments, dyes, plastics, and electronic industries.

Preparation^[1-2]

Report 1,

Put 1200Kg concentrated sulfuric acid and 560Kg phthalic anhydride into the reaction kettle, stir and raise the temperature to 50°C, start adding 500KG concentrated nitric acid dropwise, the reaction exothermic mixture heats up, and control the reaction temperature not to exceed 100°C. After the nitric acid is added dropwise, 100°C/ 2h, 110℃/2h insulation reaction is complete.

After the reaction is completed, cool and put the nitrated materials into the hydrolysis kettle. 1500Kg of ice water is added to the hydrolysis kettle in advance. After the addition is completed, cool and suction filter at 80°C/3h to obtain nitrophthalic acid.

Preliminarily add 1500Kg of water to the separation pot, add the above-mentioned nitrophthalic acid, stir at room temperature for 4 hours, and then separate the crude 3-nitrophthalic acid.

Add equal amounts of water and crude 3-nitrophthalic acid to the recrystallization pot and heat to reflux for 1 hour, then cool to room temperature, and centrifuge to obtain fine 3-nitrophthalic acid. After HPLC analysis, the content is greater than 99 %.

Report 2,

Add 10g 3-nitro-o-xylene, 20g water, 20g 65% nitric acid, 1g catalyst into a 100mL magnetic stirring tank, add oxygen, control the pressure at 0.5mpa above the standard atmospheric pressure, start stirring, and raise the temperature to 80°C. Keep the reaction for 10 hours, cool to 10°C, filter, wash, and dry at 60°C for 8 hours to obtain 13.5g of 3-nitrophthalic acid, with a product mole fraction of 99.3%.

Apply^[3]

3-Nitrophthalic anhydride is an important organic synthesis intermediate and is widely used in the synthesis of dyes, medicines, fluorescent agents, etc. CN201710859090.3 provides a preparation method of 3-nitrophthalic anhydride, which uses 3-nitrophthalic acid as a starting material and synthesizes 3-nitrophthalic anhydride in one step through catalytic dehydration. High efficiency and low cost. Here’s how:

Preparation method of 3-nitrophthalic anhydride: place 212 grams of 3-nitrophthalic acid in a reaction solvent, the reaction solvent is 300 grams of toluene and 50 grams of acetic acid, and then add 6 grams of p-toluene Sulfonic acid, raise the temperature to 100-150°C and react for 4-12 hours, take a sample and detect by HPLC when the 3-nitrophthalic acid content is less than 1%, stop heating; the obtained material is removed under the condition of negative pressure -0.08–0.098Mpa Toluene, acetic acid, and p-toluenesulfonic acid were used to obtain 184.5 grams of 3-nitrophthalic anhydride, with a content of 98% and a yield of 95.1%.

References

[1][Chinese invention] Preparation method of CN02138552.13-nitrophthalic acid

[2][China invention, China invention authorization] CN201210042243.2 A synthesis method of 3-nitrophthalic acid

[3][Chinese invention] Preparation method of CN201710859090.33-nitrophthalic anhydride