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Preparation method of o-nitrobenzaldehyde

The technology of o-nitrobenzaldehyde and o-nitrotoluene is applied in the field of preparation of organic pharmaceutical intermediates, and can solve the problems of difficult examination and approval, unfriendly environment, and high equipment requirements, and achieves improved bromination selectivity and conversion rate, The effect of reducing the difficulty of purification and reducing environmental pressure

Inactive Publication Date: 2018-10-16
常州恒达生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has the following disadvantages: 1) bromine is highly corrosive, requires high equipment, and has a high safety risk; 2) bromine, as a precursor chemical, is difficult to approve; 3) during the reaction process, dibromination and multiple Bromination is not easy to control, there are many side reactions, and it is not easy to purify in the later stage; 4) Sodium metabisulfite is used for extraction, the amount of wastewater is large, and the environment is not friendly

Method used

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  • Preparation method of o-nitrobenzaldehyde

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] A kind of production technique of o-nitrobenzaldehyde, its step is as follows:

[0026] (1) Bromination Add the measured water, dichloroethane, o-nitrotoluene, and hydrobromic acid into the reaction kettle in turn, add ice brine (or cooling water to cool down) into the condenser, add hydrogen peroxide dropwise under stirring, and add Initiator AIBN, then add hydrogen peroxide and AIBN in batches for several times, each time the color needs to fade, all the hydrogen peroxide drops, and then keep warm for 1-2 hours until the color fades, cool down, and transfer to the hydrolysis kettle.

[0027] The weight ratio of each raw material is o-nitrotoluene: water: hydrobromic acid: dichloroethane: hydrogen peroxide: initiator=1:0.3:1:1:1.5:0.07.

[0028] (2) Hydrolysis Prepare 10% sodium hydroxide solution in the reaction kettle, add the reaction solution obtained in the bromination process into the hydrolysis kettle and stir, heat up and reflux, keep warm and separate into lay...

Embodiment 2

[0031] Initiator is EHP, o-nitrotoluene: water: hydrobromic acid: ethylene dichloride: hydrogen peroxide: initiator=1:0.5:1.5:1.5:1:0.5, operation is the same as embodiment one, o-nitrobenzaldehyde total Yield 62%, purity 99%.

Embodiment 3

[0033] With embodiment one, hydrolyze 10% sodium hydroxide, change 15% Na2CO3 o-nitrobenzaldehyde yield 67%, purity 99%.

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Abstract

The invention relates to a method for preparing o-nitrobenzaldehyde. The method comprises the following steps of using hydrobromic acid as a brominating agent, brominating, hydrolyzing and oxidizing.The method is characterized in that the usage amount and speed of hydrogen peroxide are regulated, and the brominating rate is controlled, so that the polybrominating is effectively controlled, and the production of byproducts is decreased; the purity can reach 99% or above without special purifying, the production of a large amount of wastewater in the common purifying method is avoided, and thetotal yield rate is 55 to 75%.

Description

technical field [0001] The invention relates to a preparation method of an organic pharmaceutical intermediate, especially a preparation method of o-nitrobenzaldehyde. Background technique [0002] O-nitrobenzaldehyde is a widely used pharmaceutical intermediate, widely used in the treatment of various heart and blood diseases. [0003] In the domestic industrialization route about o-nitrobenzaldehyde, bromine is generally used as the bromination reagent, and steps such as bromination, hydrolysis, oxidation, extraction (sodium pyrosulfite), and neutralization are generally used. This method has the following disadvantages: 1) bromine is highly corrosive, requires high equipment, and has a high safety risk; 2) bromine, as a precursor chemical, is difficult to approve; 3) during the reaction process, dibromination and multiple Bromination is not easy to control, there are many side reactions, and it is not easy to purify in the later stage; 4) Sodium metabisulfite is used for...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/12C07C205/44
CPCC07C201/12C07C205/44C07C205/11C07C205/19
Inventor 文宁锋孙一飞曹海珍
Owner 常州恒达生物科技有限公司