Method for recycling acid in synthesis of 2-nitro-4-methylsulfonylbenzoic acid

A technology for thiamphenicol benzoic acid and acid recovery, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve unfavorable industrialized production, safe and stable progress, restriction of enterprise and social and economic development, existence safety and environmental protection Risk and other issues, to achieve the effect of solving safety and environmental risks, solving difficult to handle, and reducing the unit consumption of raw materials

Active Publication Date: 2020-06-19
利民化学有限责任公司
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  • Abstract
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AI Technical Summary

Problems solved by technology

[0003] During the synthesis of 2-nitro-4-thiamphenicol benzoic acid, a large amount of waste acid solution will be produced, which is difficult to handle, and a side reaction will occur in the nitration reaction to generate 2,6-dinitro-4-thiamphenicol toluene, and even polynitro by-products
In the process of reclaiming the acid solution for recycling, polynitro by-products accumulate continuously. When the concentration of polynitro by-products is high, it will affect the content and yield of the product. At the same time, there are safety and environmental risks, which is not conducive to the safety of industrial production. Smooth progress, restricting the economic development of enterprises and society

Method used

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  • Method for recycling acid in synthesis of 2-nitro-4-methylsulfonylbenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] After filtering the crude 2-nitro-4-thiamphenicol benzoic acid, the dilute acid mother liquor is concentrated to 170-180°C under the condition of vacuum degree of 0.095-0.1MPa to obtain recovered acid with a concentration of 90%-98%, which is continuously circulated until After the 4th cycle, get filtered dilute acid mother liquor 600g, wherein the content of polynitro-substituent is 6012ppm after analysis. Use a measuring cylinder to measure 40ml of SP700 adsorption resin, and transfer it into two adsorption columns respectively, keep it firm, and keep a 3-5cm water layer on the upper layer of the resin. Connect the diluted acid mother liquor to be adsorbed, the peristaltic pump, and the two adsorption columns with rubber tubes. At 5-10°C, the peristaltic pump controls the flow rate to 0.5-1BV / h, so that the diluted acid mother liquor passes through the adsorption column, and then washes the adsorption column with 80ml of water, and the effluent is combined with the di...

Embodiment 2

[0036] After filtering the crude 2-nitro-4-thiamphenicol benzoic acid, the dilute acid mother liquor is concentrated to 170-180°C under the condition of vacuum degree of 0.095-0.1MPa to obtain recovered acid with a concentration of 90%-98%, which is continuously circulated until After the 6th cycle, get filtered diluted acid mother liquor 600g, wherein the content of nitro substitute is 7203ppm after analysis. Use a measuring cylinder to measure 40ml of SP825L adsorption resin, and transfer it into two adsorption columns respectively, keep it firm, and keep a 3-5cm water layer on the upper layer of the resin. Connect the dilute acid to be adsorbed, the peristaltic pump, and the two adsorption columns with rubber tubes. At 20-30°C, the peristaltic pump controls the flow rate to 2-2.5BV / h, so that the dilute acid mother liquor passes through the adsorption column, and then washes the adsorption column with 120ml of water, and the effluent is combined with the diluted acid mother...

Embodiment 3

[0041] After filtering the crude 2-nitro-4-thiamphenicol benzoic acid, the dilute acid mother liquor is concentrated to 170-180°C under the condition of vacuum degree of 0.095-0.1MPa to obtain recovered acid with a concentration of 90%-98%, which is continuously circulated until After the 5th cycle, get filtered diluted acid mother liquor 600g, wherein the content of nitro substituent is 6872ppm after analysis. Use a graduated cylinder to measure 40ml of SP207 adsorption resin, and transfer it into two adsorption columns respectively, keep it firm, and keep a 3-5cm water layer on the upper layer of the resin. Connect the dilute acid to be adsorbed, the peristaltic pump, and the two adsorption columns with rubber tubes. At 55-60°C, the peristaltic pump controls the flow rate to 3-4BV / h, so that the diluted acid mother liquor passes through the adsorption column, and then washes the adsorption column with 100ml of water, and the effluent is combined with the diluted acid mother ...

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Abstract

The invention relates to a method for recycling acid in synthesis of 2-nitro-4-methylsulfonylbenzoic acid, which comprises the following steps of 1) by using 4-methylsulfonyltoluene as a raw material,carrying out nitration reaction and oxidation reaction in a concentrated sulfuric acid medium, filtering dilute acid mother liquor obtained after the 2-nitro-4-methylsulfonylbenzoic acid crude product, and concentrating to obtain recycled acid, 2) recycling the recovered acid, and removing the reaction by-product polynitro compound from the dilute acid mother liquor by adopting a resin adsorptionmethod, so that the content of the polynitro compound in the dilute acid mother liquor after adsorption is less than 200 ppm, 3) concentrating the adsorbed dilute acid mother liquor, applying the concentrated dilute acid mother liquor to the nitration reaction, and supplementing the required catalyst to continue the oxidation reaction after the nitration reaction is finished, and 4) desorbing andregenerating the adsorbed resin through solvent desorption, concentrating, filtering and washing to recover the reaction by-product, thereby avoiding the safety and environmental protection risks caused by continuous accumulation of the by-product concentration in the synthesis process, and being safe, practical, green and environment-friendly, and suitable for industrial implementation.

Description

technical field [0001] The invention relates to a method for synthesizing 2-nitro-4-thiamphenicol benzoic acid, in particular to a method for recycling acid in the synthesis of 2-nitro-4-thiamphenicol benzoic acid. Background technique [0002] 2-Nitro-4-thiamphenicolbenzoic acid, also known as o-nitro-4-thiamphenicolbenzoic acid, English name is 2-Nitro-4-methylsulfonylbenzoic acid, CAS number is 110964-79-9. 2-Nitro -4-Thiamphenicol benzoic acid is an important intermediate in the production of the herbicide mesotrione, and is widely used in the production of dyes, medicines and pesticides. Industrial production mostly uses 4-thiamphenicol toluene as raw material, nitration reaction in concentrated sulfuric acid medium to obtain 2-nitro-4-thiamphenicol toluene, and then oxidation reaction of 2-nitro-4-thiamphenicol toluene The crude product of 2-nitro-4-thiamphenicol benzoic acid is obtained, and the finished product of 2-nitro-4-thiamphenicol benzoic acid is obtained thr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C315/04C07C317/44
CPCC07C315/04C07C317/44
Inventor 许宜伟李新生徐宁孙敬权李林虎孙丽梅陈浩郑翠秀
Owner 利民化学有限责任公司
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