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Method for co-production 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid

A technology of toluic acid and nitrobenzoic acid, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of low selectivity and high risk of 3-nitro-o-xylene, To achieve the effect of easy recycling, high economic value and less waste salt

Active Publication Date: 2020-09-29
JIANGSU YONGAN CHEM CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] For the deficiencies in the prior art, the object of the present invention is to provide a method for the co-production of 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid. 3-nitro-2-methylbenzoic acid (or 3-nitro-2-methylbenzoic acid ester) is prepared with oxygen as an oxidant, and 2-methyl-6-nitrobenzoic acid is co-produced, Solve the problem of low selectivity in the oxidation process of 3-nitro-o-xylene and high risk in the oxidation process of concentrated nitric acid

Method used

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  • Method for co-production 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid
  • Method for co-production 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid
  • Method for co-production 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] (1) Add 3-nitro-o-xylene (200 g) and 30% nitric acid (1000 g) into the oxidation reaction kettle, raise the temperature to 130-140°C, pass the oxygen pressure to 2.2-2.5 MPa, and keep stirring for 7 hours;

[0040] (2) Cool down to 20-30°C and filter to obtain 193 g of crude product (HPLC: 3-nitrophthalic acid 6.63%, 2-methyl-6-nitrobenzoic acid 15.92%, 3-nitro-2- Toluic acid 60.74%, 3-nitro-o-xylene 8.66%);

[0041] (3) The crude product was washed three times with 200 g of water to obtain 142 g of filter cake (HPLC spectrum as figure 1 Shown: 3-nitrophthalic acid 0.52%, 2-methyl-6-nitrobenzoic acid 12.3%, 3-nitro-2-methylbenzoic acid 72.03%, 3-nitro-o-xylene 7.1 %);

[0042] (5) Add 500 g of butanol and 5 g of p-toluenesulfonic acid to the crude product obtained in step 3, heat up and reflux for azeotropic dehydration, and start distillation to recover the solvent after the esterification reaction is complete.

[0043] (6) Cool the concentrated solution to 20-30°C,...

Embodiment 2

[0046] (1) Add 3-nitro-o-xylene (200 g) and 35% nitric acid (1000 g) into the oxidation reaction kettle, raise the temperature to 120-130 ° C, pass oxygen pressure 2.0-2.2 MPa, and keep stirring for 12 hours;

[0047] (2) Cool down to 10-20°C and filter to obtain 220 g of crude product (HPLC: 21.6% of 3-nitrophthalic acid, 24.7% of 2-methyl-6-nitrobenzoic acid, 3-nitro-2- Toluic acid 35.2%, 3-nitro-o-xylene 7.47%);

[0048] (3) The crude product was washed three times with 200 g of water to obtain a filter cake of 125 g (HPLC: 1.52% of 3-nitrophthalic acid, 24.2% of 2-methyl-6-nitrobenzoic acid, 3-nitro-2 -Toluic acid 52.03%, 3-nitro-o-xylene 7.05%);

[0049] (5) Add 800 g of methanol and 10 g of sulfuric acid to the crude product obtained in step 3, heat up to reflux for 4 hours, then continue to heat up to 80-90°C, and start distillation to recover methanol after the esterification reaction is complete.

[0050] (6) Heat the concentrated solution at 80-90°C, add 50 g of wa...

Embodiment 3

[0053] (1) Add 3-nitro-o-xylene (200 g) and 10% nitric acid (1200 g) into the oxidation reaction kettle, raise the temperature to 145-150 ° C, pass oxygen pressure 3.5-4.0 MPa, and keep stirring for 18 hours;

[0054] (2) Cool down to 75-85°C and filter while hot to obtain 90 grams of crude 3-nitro-2-methylbenzoic acid (HPLC: 2.71% 3-nitrophthalic acid, 2-methyl-6- Nitrobenzoic acid 6.76%, 3-nitro-2-methylbenzoic acid 80.04%, 3-nitro-o-xylene 5.36%), filtrate weight 1300 g, nitric acid concentration 5.5%;

[0055] (3) The filter cake was washed with 80 g of water at 80°C, and the washing liquid was collected. Filter cake after water washing (HPLC spectrogram as Figure 4 As shown) weighed 75 g, added 75 g of anhydrous methanol, heated to 65 ° C to dissolve, filtered out the insoluble matter while it was hot, cooled the filtrate to crystallize, kept at 15-20 ° C for 1 hour, filtered and dried to obtain 3-nitro-2- 60 g of methyl benzoic acid finished product (HPLC spectrogram ...

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Abstract

The invention discloses a method for co-production of 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid. The method is characterized by comprising the following steps: (1) feeding 3-nitro-o-xylene and dilute nitric acid into an oxidation reaction kettle, carrying out heating, and conducting reacting under certain pressure by using oxygen as an oxidant; (2) after the reaction is finished, discharging an oxidation reaction solution to obtain a crude product; (3) washing the crude product with water, conducting esterifying, and performing distilling to recover a solvent after the reaction is finished, thereby obtaining an esterified concentrated solution; (4) adding alkali into the esterification concentrated solution to adjust a pH value, carrying out layering, and distilling anorganic layer under reduced pressure to recover 3-nitro-2-nitrobenzoic acid; and (5) extracting a water layer with an organic solvent, adjusting an pH value with an acid, and performing filtering anddrying to obtain the 2-methyl-6-nitrobenzoic acid. In a low-concentration nitric acid environment, 3-nitro-2-nitrobenzoic acid is produced and 2-methyl-6-nitrobenzoic acid is co-produced with oxygen used as an oxidizing agent, so the problems of low selectivity of 3-nitro-o-xylene in an oxidation process and high risks in a concentrated nitric acid oxidation process are solved.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and relates to the synthesis of organic intermediates, in particular to a method for the joint production of 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid. Background technique [0002] 2-Methyl-6-nitrobenzoic acid is an important raw material for the synthesis of 2-methoxy-6-methylbenzoic acid, a key intermediate of the pesticide fungicide metrafenone. Metrafenone was first produced as a benzophenone-type fungicide metrafenone by the American Cyanoamine Company (now owned by BASF, Germany). Actin, the cytoskeleton of the pathogen, is destroyed and disintegrated, resulting in abnormal branching of the mycelium and slowing down the growth, so as to achieve the purpose of preventing and controlling powdery mildew. It has excellent activity against powdery mildew and eye spot disease on grains, melons, beans, grapes and other crops. It was launched in the UK in 2004. In th...

Claims

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Application Information

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IPC IPC(8): C07C201/12C07C205/57C07C201/16
CPCC07C201/12C07C201/16C07C205/57
Inventor 耿敬坤
Owner JIANGSU YONGAN CHEM CO LTD
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