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Preparation method of 4-acetylbenzoic acid

A technology of acetyl benzoic acid and anhydrous acetic acid is applied in the preparation of carboxylate, the preparation of organic compounds, chemical instruments and methods, etc., and can solve the problems of large discharge of three wastes, high reaction temperature, and large amount of potassium permanganate. , to achieve the effect of environmental protection in the production process, reducing the amount of solvents, and reducing the discharge of three wastes

Inactive Publication Date: 2012-10-03
扬州市天平化工厂有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the past, the production cost of synthesizing 4-acetylbenzoic acid was high, and the discharge of three wastes was large, which greatly affected the use and promotion. In the prior art, the reaction temperature was high, the amount of potassium permanganate was large, and the reaction time was long

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Add 500 kg of water, 100 kg of p-methylacetophenone, and 12 kg of anhydrous zinc chloride into the reaction pot, stir evenly, slowly heat up to 35~40°C, turn off the steam, and start adding high manganese in batches Potassium acid potassium 75 kg, add 15 kg each time, add once every 20 minutes, control the reaction temperature at 48~55°C by feeding, add water to cool if necessary, react at 40~45°C after feeding, keep warm for 1.5 hours, detect the end of the reaction, start Cool down to 17~22°C, centrifuge to remove waste manganese salt, pump the liquid layer into another reaction pot, add petroleum ether at 90~120°C and stir for 15 minutes, let stand to separate layers, separate the water layer, evaporate the ether layer to remove petroleum ether, 1.05 kg of raw materials were obtained for reuse, and the water layer was neutralized with 20% sulfuric acid to pH=1~2, centrifuged, washed with an appropriate amount of water to obtain crude products, and dried in a drying ro...

Embodiment 2

[0018] Add 600 kg of water, 110 kg of p-methylacetophenone, and 14 kg of anhydrous zinc chloride into the reaction pot, stir evenly, slowly heat up to 35~40°C, turn off the steam, and start adding high manganese in batches Potassium acid potassium 85 kg, add 17 kg each time, add once every 20 minutes, control the reaction temperature at 48~55°C by feeding, add water to cool if necessary, react at 40~45°C after feeding, keep warm for 1.5 hours, detect the end of the reaction, start Cool down to 17~22°C, centrifuge to remove waste manganese salt, pump the liquid layer into another reaction pot, add petroleum ether at 90~120°C and stir for 15 minutes, let stand to separate layers, separate the water layer, evaporate the ether layer to remove petroleum ether, 1.2 kg of raw materials were obtained for reuse, and the water layer was neutralized with 20% sulfuric acid to pH=1~2, centrifuged, washed with an appropriate amount of water to obtain crude products, and dried in a drying roo...

Embodiment 3

[0021] Add 420 kg of water, 90 kg of p-methylacetophenone, and 10 kg of anhydrous zinc chloride into the reaction pot, stir evenly, slowly heat up to 35~40°C, turn off the steam, and start adding high manganese in batches Potassium acid potassium 65 kg, add 13 kg each time, add once every 20 minutes, control the reaction temperature 48~55°C during feeding, add water to cool if necessary, react at 40~45°C after feeding, keep warm for 1.5 hours, detect the end of the reaction, start Cool down to 17~22°C, centrifuge to remove waste manganese salt, pump the liquid layer into another reaction pot, add petroleum ether at 90~120°C and stir for 15 minutes, let stand to separate layers, separate the water layer, evaporate the ether layer to remove petroleum ether, 9.25 kg of raw materials were obtained for reuse, and the water layer was neutralized with 20% sulfuric acid to pH = 1~2, centrifuged, washed with an appropriate amount of water to obtain crude products, and dried in a drying ...

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Abstract

The invention discloses a preparation method of 4-acetylbenzoic acid. The preparation method comprises the following steps of: (1) oxidizing: adding 4-methyl acetophenone, water and anhydrous zinc chloride to a reaction pot, stirring uniformly, slowly heating to 35-45 DEG C, averagely dividing potassium permanganate into five parts, adding one part every 15-20min, controlling the reaction temperature at 48-55 DEG C during adding, after adding is finished, controlling the reaction temperature at 40-45 DEG C, carrying out heat insulation for 1.5h, then cooling to 17-22 DEG C, centrifuging, and baking to obtain 4-acetylbenzoic acid crude product; and (2) mixing prepared crude product with anhydrous acetic acid, heating and refluxing for 0.5-1.5h, carrying out hot filtering, centrifuging and baking to obtain 4-acetylbenzoic acid. The method has the advantages that the production cost is low, batched oxidation is adopted, the solvent consumption is reduced, the discharge of three wastes is reduced, the production process is environment-friendly and the yield is high.

Description

technical field [0001] The invention relates to a method for preparing a main intermediate in the synthesis of benzimidazole and derivatives thereof, in particular to a method for preparing 4-acetylbenzoic acid. Background technique [0002] 4-Acetylbenzoic acid mainly synthesizes the synthesis of new drug intermediate N-methyl-2-(4-acetyl-5-nitrobenzimidazole, and benzimidazole and its derivatives are active ingredients of many new drugs. Such as Cramizol antihistamines, etitrazine, strong analgesics, benzyl imidazole, antispasmodics and antifungal drugs belong to this kind of derivatives, and its synthesis has certain theoretical significance and strong practical value. Previously The production cost of synthesizing 4-acetylbenzoic acid is high, and the discharge of three wastes is large, which greatly affects the application and promotion. In the prior art, the reaction temperature is high, the consumption of potassium permanganate is large, and the reaction time is long....

Claims

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Application Information

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IPC IPC(8): C07C65/32C07C51/21
Inventor 吕欢欢马文元张兴华
Owner 扬州市天平化工厂有限公司
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