Method for preparing 3-nitro phthalic acid

Abstract

The preparation method of 3-nitrophthalic acid includes the following processes: a. using phenylanhydride as raw material, and using nitration agent to obtain nitrophenylanhydride; b. making hydrolysis to produce nitrophthalic acid; and c. then utilizing solubility property in the solvent, separating isomer 4-nitrophthalic acid and other impurity and synthesizing to obtain high-purity 3-nitrophthalic acid whose content is greater than 99%. Said invention possesses the advantages of low cost, convenient preparation, small pollution and high finished product content.

Description

technical field

[0001] The invention relates to the field of chemical industry, in particular to a preparation method of 3-nitrophthalic acid. Background technique

[0002] 3-nitrophthalic acid is an important intermediate in pesticides, pigments, dyes, plastics, and electronics industries. There are many ways to prepare 3-nitrophthalic acid, Bailstein and Kurdatou Ann Chem (Liebig) 1880, 202 , In the 217 literature, use 1-nitronaphthalene, nitric acid, potassium permanganate, potassium dichromate, oxidation method, need high temperature, high pressure, potassium dichromate, environmental protection problem, potassium permanganate, oxidation selectivity is low, Not suitable for industrial production. International patent WO85-02, the method for preparing 3-nitrophthalic acid in No. 615 is that phthalic acid or phthalic anhydride is nitrated with a large amount of concentrated nitric acid, with a weight ratio of 1: 10 to 15, and reacted at 70°C to 80°C. The method requires ...

Examples

Embodiment Construction

[0010] Preparation of 3-nitrophthalic acid:

[0011] Put 1200Kg of concentrated sulfuric acid and 560Kg of phthalic anhydride into the reaction kettle, stir and raise the temperature to 50°C, start to add 500KG of concentrated nitric acid dropwise, and the reaction exothermic mixture is heated up, and the reaction temperature is controlled not to exceed 100°C. ℃ / 2h insulation reaction is complete.

[0012] After the reaction, cool down, put the nitrated material into the hydrolysis kettle, add 1500Kg of ice water to the hydrolysis kettle in advance, after the addition, cool and suction filter at 80°C / 3h to obtain nitrophthalic acid.

[0013] Add 1500Kg of water to the separation pot in advance, add the above-mentioned nitrophthalic acid, stir at room temperature for 4 hours, and then separate to obtain the crude product of 3-nitrophthalic acid.

[0014] Add an equal amount of water and crude 3-nitrophthalic acid into a recrystallization pot, heat and reflux for 1 hour, cool t...

technical field

[0001] The invention relates to the field of chemical industry, in particular to a preparation method of 3-nitrophthalic acid. Background technique

[0002] 3-nitrophthalic acid is an important intermediate in pesticides, pigments, dyes, plastics, and electronics industries. There are many ways to prepare 3-nitrophthalic acid, Bailstein and Kurdatou Ann Chem (Liebig) 1880, 202 , In the 217 literature, use 1-nitronaphthalene, nitric acid, potassium permanganate, potassium dichromate, oxidation method, need high temperature, high pressure, potassium dichromate, environmental protection problem, potassium permanganate, oxidation selectivity is low, Not suitable for industrial production. International patent WO85-02, the method for preparing 3-nitrophthalic acid in No. 615 is that phthalic acid or phthalic anhydride is nitrated with a large amount of concentrated nitric acid, with a weight ratio of 1: 10 to 15, and reacted at 70°C to 80°C. The method requires ...

Examples

Embodiment Construction

[0010] Preparation of 3-nitrophthalic acid:

[0011] Put 1200Kg of concentrated sulfuric acid and 560Kg of phthalic anhydride into the reaction kettle, stir and raise the temperature to 50°C, start to add 500KG of concentrated nitric acid dropwise, and the reaction exothermic mixture is heated up, and the reaction temperature is controlled not to exceed 100°C. ℃ / 2h insulation reaction is complete.

[0012] After the reaction, cool down, put the nitrated material into the hydrolysis kettle, add 1500Kg of ice water to the hydrolysis kettle in advance, after the addition, cool and suction filter at 80°C / 3h to obtain nitrophthalic acid.

[0013] Add 1500Kg of water to the separation pot in advance, add the above-mentioned nitrophthalic acid, stir at room temperature for 4 hours, and then separate to obtain the crude product of 3-nitrophthalic acid.

[0014] Add an equal amount of water and crude 3-nitrophthalic acid into a recrystallization pot, heat and reflux for 1 hour, cool t...