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Preparation method of o-aminoacetophenone

A technology of o-aminoacetophenone and nitroacetophenone, which is applied in the field of preparation of o-aminoacetophenone, can solve problems such as low yield of final products, and achieve the effects of low production cost and mild reaction conditions

Active Publication Date: 2020-09-18
成家钢
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this preparation method, the yield of o-nitroacetophenone in step (1) only only has 40-70%, causes the yield of final product to be also lower

Method used

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  • Preparation method of o-aminoacetophenone

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preparation example Construction

[0022] A preparation method for o-aminoacetophenone, comprising the following steps:

[0023] (1) react oxidant potassium permanganate, acid catalyst, o-nitroethylbenzene in dilute sulfuric acid environment, after the reaction is finished, extract, wash, and dry to obtain o-nitroacetophenone;

[0024] (2) Add the o-nitroacetophenone and reduced metals obtained in step (1) to continuous reflux reaction in ammonium chloride aqueous solution. After the reaction is over, feed steam into the reaction kettle for distillation, and carry out the distilled solution. Separation can give o-aminoacetophenone.

[0025] It should be noted that: step (1) can only be reacted under acidic conditions. When reacting under alkaline environmental conditions, the product obtained will be affected. For example, when reacting under the alkaline conditions of sodium hydroxide, the obtained The product is o-nitrobenzoic acid. The oxidizing agent in the step (1) can only use potassium permanganate, an...

Embodiment 1

[0038]Preparation of o-nitroacetophenone: Add 210L of water into a 1000L enamel reaction kettle, start stirring, pass cooling water through the jacket of the kettle, slowly add 94kg of concentrated sulfuric acid dropwise, and add 3kg of glacial acetic acid, control the temperature at 30-40 degrees, and then Add 100kg o-nitroethylbenzene (662mol), and add 162kg potassium permanganate (1025mol) in small batches in 6 hours under rapid stirring, keep the temperature in the kettle no more than 50 degrees, and keep stirring for 2 hours after the potassium permanganate is added. hour, then add 10kg of industrial salt, stir and cool down to 30 degrees, let it stand for half an hour, after the manganese dioxide mud and the oil layer are clearly separated, the oil layer is sucked out under negative pressure; add 110kg of industrial benzene to the oily manganese mud left in the kettle, 10kg of salt, stir rapidly for 20 minutes, and then slowly stir for 10 minutes. After the manganese mud ...

Embodiment 2

[0041] Preparation of o-nitroacetophenone: Add 210L of water into a 1000L enamel reaction kettle, start stirring, pass cooling water through the jacket of the kettle, slowly add 94kg of concentrated sulfuric acid dropwise, and add 2.5kg of glacial acetic acid, control the temperature at 30-40 degrees, Then add 100kg o-nitroethylbenzene (662mol), and add 138kg potassium permanganate (873mol) in small batches in 6 hours under rapid stirring, keep the temperature in the kettle not exceeding 50 degrees, and keep stirring after the potassium permanganate is added. 2 hours, then add 10kg of industrial salt, stir and cool down to 30 degrees, let it stand for half an hour, after the manganese dioxide mud and the oil layer are clearly separated, suck out the oil layer under negative pressure; add 110kg of industrial benzene to the oily manganese mud left in the kettle, 10kg of industrial salt, stir rapidly for 20 minutes, then slowly stir for 10 minutes, after the manganese mud and benz...

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Abstract

The invention relates to the technical field of organic intermediate synthesis, in particular to a preparation method of o-aminoacetophenone. The preparation method of o-aminoacetophenone provided bythe invention comprises the following steps: adding potassium permanganate into o-nitroethylbenzene in batches in an acidic environment of dilute sulfuric acid to carry out oxidation reaction to generate o-nitroacetophenone; reducing the o-nitroacetophenone into o-aminoacetophenone by using iron powder; and distilling off o-aminoacetophenone by using water vapor. The reaction conditions are mild,the production cost is low, the method is suitable for industrial mass production, the yield of the o-nitroacetophenone can reach 70% or above, the yield of the o-aminoacetophenone can reach 90% or above, and the yield of the o-nitroacetophenone and the yield of the o-aminoacetophenone can both reach 95% or above when weak acid glacial acetic acid is adopted as a catalyst and all the raw materialsare kept in the optimal proportion and react under the optimal reaction condition.

Description

technical field [0001] The invention relates to the technical field of organic intermediate synthesis, in particular to a preparation method of o-aminoacetophenone. Background technique [0002] O-aminoacetophenone is an important intermediate of the hypoglycemic drug Linagliptin, and it is one of the important hot spots in current drug research. [0003] Patent CN107162923B discloses a preparation method of o-aminoacetophenone, including: in anhydrous or nearly anhydrous solvent, methyllithium and isatoic anhydride are reacted at a reaction temperature below -50°C, the reaction is completed, and then Process to obtain the target product o-aminoacetophenone. In this preparation method, the two main raw materials involved, methyllithium and isatoic anhydride, are expensive. In addition, the reaction at -50°C requires harsh reaction conditions and high production costs; [0004] The invention patent with application number 201911252092.1 discloses a preparation method of o-a...

Claims

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Application Information

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IPC IPC(8): C07C225/22C07C221/00
CPCC07C221/00C07C201/12C07C225/22C07C205/45
Inventor 成家钢
Owner 成家钢
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