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Preparation method of 2-nitro-4-methylsulphonylbenzoic acid

A technology of methylsulfonyl benzoic acid and methylsulfonyl toluene is applied in the field of catalytic oxidation synthesis technology of 2-nitro-4-methylsulfonyl benzoic acid, and can solve the problem that the degree of oxidation reaction is difficult to control, the oxidizing ability is limited, and the Difficulty in methyl oxidation and other problems, to achieve the effect of reducing waste water pollution, high conversion rate and selectivity, and eliminating waste gas pollution

Active Publication Date: 2014-05-14
SINOCHEM AGRO +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] There are two strong electron-withdrawing groups on 2-nitro-4-thiamphenicol toluene, which makes it difficult to oxidize the methyl group on the benzene ring, and it is also difficult to control the degree of oxidation in the oxidation reaction.
These methods do not consume expensive chemical oxidants, do not produce waste gas, waste liquid, and are beneficial to environmental protection, but there are problems such as limited oxidation capacity and low conversion rate.

Method used

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  • Preparation method of 2-nitro-4-methylsulphonylbenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0054] The experiment was carried out in a stirred reactor with a volume of 1000ml, glacial acetic acid 800ml, water 50g, 2-nitro-4-thiamphenicol toluene 80g, phosphomolybdovanadate 6g, manganese sulfate 9.5g, potassium iodide 0.6g were added, and the reaction The temperature is 180°C, the pressure is 40atm, and the air flow rate is 500ml / min. After the reaction starts, liquid samples are taken every 0.5h and analyzed by liquid chromatography. After 4h of reaction, the conversion rate of 2-nitro-4-thiamphenicol toluene reaches 95%. , The yield of 2-nitro-4-thiamphenicol benzoic acid reached 91%.

[0055] The reaction solution was cooled to 5°C, and the precipitate was separated from the reaction solution by filtration.

[0056] Gained solid precipitation is fully dissolved with the sodium hydroxide solution of 200ml 15% (mass), filters insoluble solid impurity, and the filtrate of filtering gained is adjusted to pH1.0 with sulfuric acid again, and crystallization precipitates ...

Embodiment 2

[0059] The experiment was carried out in a reactor with a volume of 1000ml. The gas-liquid two-phase flowed through the reactor continuously from bottom to top. The flow rate of the liquid was 5ml / min, and the flow rate of the air was 500ml / min. In the liquid feed, 2-nitro- 10% (mass) of 4-thiamphenicol toluene, 10% (mass) of water, 0.70% (mass) of phosphomolybdovanadic acid, 0.30% (mass) of manganese, 0.05% (mass) of iodine, the rest are acetic acid, and the reaction temperature is 210 ℃, pressure 30atm, the outlet liquid of the reactor was analyzed by liquid chromatography, the conversion rate of 2-nitro-4-thiamphenicol toluene reached 96%, and the yield of 2-nitro-4-thiamphenicol benzoic acid reached 91%.

Embodiment 3

[0061] The experiment was carried out in a stirred reactor with a volume of 1000ml, adding 800ml of glacial acetic acid, 80g of water, 80g of 2-nitro-4-thiamphenicol toluene, 4g of phosphotungstic acid, 2g of cobalt acetate, 4g of manganese acetate, tetrabromoethyl Alkane 0.5g, reaction temperature 210 ℃, pressure 30atm, air flow rate is 500ml / min, after the reaction begins, take liquid sample every 0.5h and use liquid chromatography analysis, after reaction 4h, 2-nitro-4-thiamphenicol toluene The conversion rate reaches 98%, and the yield of 2-nitro-4-thiamphenicol benzoic acid reaches 91%.

[0062] The reaction solution was cooled to 5°C, and the precipitate was separated from the reaction solution by filtration.

[0063] The resulting solid precipitate was purified by the method described in Example 1 to obtain 80.3 g of pale yellow 2-nitro-4-thiamphenicol benzoic acid.

[0064] Add 50ml of glacial acetic acid to the resulting filtrate, then add 80g of 2-nitro-4-thiampheni...

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Abstract

The invention relates to a preparation method of 2-nitro-4-methylsulphonylbenzoic acid. The preparation method comprises the steps of using 2-nitro-4-methyltolylsulfone as a raw material in a reactor under the 5-75 atmospheric pressure at the temperature of 110-450 DEG C, feeding air, oxygen-enriched air or oxygen which serves as oxidizing gas, using low-grade carboxylic acid as a solvent, adopting heteropolyacid, transition metal and halide to form a multi-element homogeneous catalysis system, producing gas-liquid reaction to convert 2-nitro-4-methyltolylsulfone in reaction liquid into the 2-nitro-4-methylsulphonylbenzoic acid; performing filtration to obtain a crystallized and sedimented 2-nitro-4-methylsulphonylbenzoic acid product after the reaction finishes; continuously recycling filtrate, namely supplementing the raw material and then performing oxidizing reaction. The defect that an existing 2-nitro-4-methylsulphonylbenzoic acid producing method causes large exhaust gas and wastewater pollution, severe corrosion, low selectivity, high production cost and the like is overcome, the selectivity is improved, the environmental pollution is reduced, and clean production of the 2-nitro-4-methylsulphonylbenzoic acid is achieved.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a catalytic oxidation synthesis process of 2-nitro-4-thiamphenicol benzoic acid. Background technique [0002] 2-Nitro-4-thiamphenicolbenzoic acid, also known as o-nitro-p-thiamphenicolbenzoic acid, CAS No. is 110964-79-9; English name is 2-Nitro-4-methylsulfonylbenzoic acid or O-Nitro -P-Methylsulfonyl Benzoic Acid (referred to as NMSBA); the molecular formula is C 8 h 7 NO 6 S, with a molecular weight of 245.21, is a white or light yellow crystalline powder at room temperature. 2-nitro-4-thiamphenicol benzoic acid is an important intermediate in organic synthesis, widely used in the production of dyes, medicines and pesticides. [0003] The preparation of 2-nitro-4-thiamphenicol benzoic acid can be obtained by oxidation of 2-nitro-4-thiamphenicol toluene: [0004] [0005] There are two strong electron-withdrawing groups on 2-nitro-4-thiamphenicol toluene, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C317/44C07C315/04
Inventor 龙湘犁杨春河李超杨志林
Owner SINOCHEM AGRO
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