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Preparation method of 2-nitro-4-methylsulfonylbenzoic acid

A technology of methylsulfonyl benzoic acid and methylsulfonyl toluene is applied in the field of preparation of 2-nitro-4-methylsulfonyl benzoic acid, and can solve the problems of large pollution of waste gas and wastewater, low selectivity, corrosion and the like, and achieves The effect of reducing by-product sulfuric acid, improving product yield and quality, and reducing environmental pollution

Inactive Publication Date: 2019-03-22
江苏新鑫隆医药科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The invention can overcome the defects of the existing 2-nitro-4-thiamphenicol benzoic acid production method, such as large waste gas and waste water pollution, serious corrosion, low selectivity and high production cost, improve selectivity, reduce environmental pollution, and realize 2 -Clean production of nitro-4-thiamphenicol benzoic acid
[0005] In the prior art, it is necessary to freeze and lower the temperature during the nitration reaction, and the reaction temperature needs to be maintained at -5°C. If the reaction temperature is too high, the reaction will easily produce dinitrobenzene or trinitrobenzene as a by-product, and the risk factor will increase.
[0006] The solvent required in the nitration reaction is concentrated sulfuric acid. After the reaction, it needs to be diluted with water to 70% sulfuric acid to continue the oxidation reaction. As a result, the sulfuric acid after the oxidation reaction cannot be recycled. If it is to be used again, the by-product sulfuric acid must be increased. Concentrated, need high temperature to increase concentration, equipment corrosion and consume a lot of energy

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] A kind of preparation method of 2-nitro-4-thiamphenicol benzoic acid, this preparation method comprises the steps:

[0022] In the nitration reactor, add 1.0 tons of dichloromethane, put 0.8 tons of p-thiamphenicol toluene, cool to 10 ° C, start to drop concentrated nitric acid, hollow sampling analysis, after the nitration reaction, put it into the oxidation reactor, slowly Heat up, distill out dichloromethane, then add 70% sulfuric acid as a solvent, add catalyst vanadium pentoxide, heat up to 140°C, add 60% nitric acid dropwise for oxidation reaction, after the reaction, cool to 25°C, centrifuge, and mother liquor Applied to the oxidation reaction, the obtained crude product is put into the reaction kettle again, water is added, lye is added dropwise to adjust the alkaline pH to 11, after impurities are filtered, the mother liquor is added dropwise with dilute sulfuric acid to adjust the pH to 1.9, cooled and centrifuged, and dried to obtain a fine product.

Embodiment 2

[0024] A kind of preparation method of 2-nitro-4-thiamphenicol benzoic acid, this preparation method comprises the steps:

[0025] In the nitration reactor, add 2.0 tons of dichloromethane, put in 1.6 tons of p-thiamphenicol toluene, cool to 10°C, start to add concentrated nitric acid dropwise, central control sampling analysis, after the nitration reaction is completed, put it into the oxidation reactor, Slowly heat up, distill out dichloromethane, then add 70% sulfuric acid as solvent, add catalyst vanadium pentoxide, heat up to 140°C, add 60% nitric acid dropwise for oxidation reaction, after the reaction, cool to 24°C, centrifuge, Apply the mother liquor to the oxidation reaction, put the obtained crude product into the reaction kettle again, add water, add lye dropwise to adjust the alkaline pH to 11, filter impurities, add dilute sulfuric acid to the mother liquor dropwise to adjust the pH to 2.1, cool and centrifuge, and dry to obtain the fine product.

Embodiment 3

[0027] A kind of preparation method of 2-nitro-4-thiamphenicol benzoic acid, this preparation method comprises the steps:

[0028] In the nitration reactor, add 1.0 tons of dichloromethane, put in 0.8 tons of p-thiamphenicol toluene, cool to 10°C, start to add concentrated nitric acid dropwise, central control sampling analysis, after the nitration reaction is completed, put it into the oxidation reactor, Slowly raise the temperature, distill out dichloromethane, then add 70% sulfuric acid as a solvent, add catalyst vanadium pentoxide, heat up to 140°C, add 60% nitric acid dropwise for oxidation reaction, after the reaction, cool to 26°C, centrifuge, Apply the mother liquor to the oxidation reaction, put the obtained crude product into the reaction kettle again, add water, add lye dropwise to adjust the alkaline pH to 11, filter impurities, add dilute sulfuric acid to the mother liquor to adjust the pH to 2.0, cool and centrifuge, and dry to obtain a fine product.

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PUM

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Abstract

The invention provides a preparation method of 2-nitro-4-methylsulfonylbenzoic acid. The preparation method comprises the following steps: adding 1.0-2.0 tons of dichloromethane and 0.8-1.6 tons of 4-(methylsulfonyl) toluene to a nitration reactor, performing cooling, starting to adding concentrated nitric acid dropwise, performing middle-control sampling analysis, putting a product into an oxidation reactor after a nitration reaction is finished, performing heating slowly to distill off dichloromethane, supplementing a solvent, adding a catalyst, performing heating, adding 60% nitric acid dropwise for an oxidation reaction, cooling a product to 25 DEG C plus / minus 1 DEG C after the reaction and centrifuging the product, recycling mother liquor to the oxidation reaction, feeding an obtained coarse product to a reaction kettle again, adding water, adding alkali liquor dropwise to regulate alkaline pH to 11, filtering out impurities, then adding dilute sulfuric acid dropwise to the mother liquor to regulate pH, and performing cooling, centrifugation and drying to obtain a refined product. Dichloromethane is used for replacing original concentrated sulfuric acid as the solvent, reaction temperature is mild, safety of the nitration reaction is improved, sulfuric acid as the byproduct of oxidation can be recycled, so that output of byproduct acid is reduced, yield of the product isincreased, and quality of the product is improved.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a preparation method 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-MethylsulfonylBenzoic Acid (NMSBA for short); the molecular formula is C8H7NO6S, the molecular weight is 245.21, and it is 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] At present, p-toluenesulfonyl chloride is mainly used to synthesize 2-nitro-4-thiamphenicol toluene as a precursor through methylation and nitration steps, and 2-nitro-4-thiamphenicol benzoic acid is synthesized by oxidation reaction; This synthesis method is wi...

Claims

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Application Information

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IPC IPC(8): C07C315/04C07C317/14C07C317/44
CPCC07C315/04C07C317/14C07C317/44
Inventor 周立冬周家林张兰姜楠张琴吉祖根
Owner 江苏新鑫隆医药科技股份有限公司
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