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ChemicalBook CAS DataBase List 3-Nitrophthalic acid

3-Nitrophthalic acid synthesis

13synthesis methods
Phthalic anhydride was added to concentrated sulfuric acid, stirring under the passage of water vapor heating to 80 °C, fuming nitric acid was added dropwise, the reaction temperature to maintain 100-110°C, add the end of the heat above 110°C for 2h, placed in the overnight pour into the water, and filtered. The filter cake was recrystallized with water to obtain 3-Nitrophthalic acid. Yield of about 30%.
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Yield:603-11-2 25.2 g

Reaction Conditions:

Stage #1:2,3-dimethylnitrobenzene with oxygen;nitric acid at 145 - 150; under 26252.6 - 30003 Torr; for 8 h;
Stage #2: with oxygen;nitric acid at 130 - 140; under 26252.6 - 30003 Torr; for 30 h;Pressure;Temperature;

Steps:

1.1-1.6; 2.1-2.6; 3.1-3.6; 4.1-4.6; 5.1-5.6; 7.1-7.6 Example 1
Example 1(1) 3-Nitro-o-xylene (100 g) and 10percent nitric acid (600 g) are added to the oxidation reactor, the temperature is raised to 145-150°C, the oxygen pressure is 3.5-4.0 MPa, and the reaction is kept warm and stirred for 8 hours;(2) Cool down to 75-80, filter while hot,Obtain 55 grams of crude 3-nitro-2-methylbenzoic acid, the filtrate weighs 650 g, and the concentration of nitric acid is 4.5percent;(3) The filter cake is washed with 11 g of water at 80°C, and the washing liquid is combined with the filtrate in step (2) to deoxidize the reactor. After washing with water, the filter cake weighed 46g, added 46 g of anhydrous methanol, heated to 65 to dissolve, filtered out the insoluble matter while it was hot, the filtrate was cooled and crystallized, and kept at 15-20 for 1 hour.Filter and dry to obtain 36 g of 3-nitro-2-methylbenzoic acid product (HPLC: 98.2percent, content: 99.0percent).(4) The filtrate obtained in step (2) is placed in an oxidation kettle, and about 110 g of concentrated nitric acid (concentration: 98percent) is added to control the nitric acid concentration to 20percent. Raise temperature to 130, oxygen pressure 4MPa, heat preservation 130-140,The pressure was 3.5-4.0MPa for 30 hours. Zhongkong HPLC detected 92.2percent of 3-nitrophthalic acid content.(5) Transfer the reaction liquid to the crystallization kettle,Cool down to crystallize, keep it at 5-10 for 1 hour, filter,Obtained 32 g of filter cake, HPLC purity 95.8percent;The filtrate weighed 725 g, and the nitric acid concentration was 18.5percent.(6) 32 g of the filter cake described in step (5),Add 64 grams of water and raise the temperature to 88-90,Stir for 30 minutes, filter while hot,The filtrate is cooled to 5-10°C and kept for 1 hour,The filter cake was filtered and dried to obtain 25.2 g, HPLC purity: 99.2percent, content: 99.8percent.

References:

Jiangsu Yong'an Chemical Co., Ltd.;Geng Jingkun;Fang Zheneng;Li Dashuang;Zhao Jingjing;Xun Weili;Du Kaiyun;Zhu Yanhua CN111362806, 2020, A Location in patent:Paragraph 0019-0044

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