Production process of m-nitrobenzaldehyde

A technology of nitrobenzaldehyde and o-nitrobenzaldehyde, which is applied in the field of preparing m-nitrobenzaldehyde, and can solve problems such as difficulty in achieving higher purity

Inactive Publication Date: 2012-01-25
GUANNAN YISITE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] The method for producing m-nitrobenzaldehyde in the present technology mainly adopts the method of refining after nitration of benzaldehyde, but because more than 20% ortho isomers are produced during nitration, it is difficult to achieve higher purity by conventional refining methods

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Embodiment 1, a kind of production technique of m-nitrobenzaldehyde, its processing step is as follows:

[0023] (1) Nitrification: add sulfuric acid and nitric acid solution into the nitrification reaction kettle, pass through the frozen brine in the insulation interlayer to cool down to -5°C, add benzaldehyde dropwise, keep warm for 1 hour after the dropwise addition, and analyze by sampling chromatography that the residual weight of benzaldehyde is 0.45 %, the material is discharged into the ice water tank, and m-nitrobenzaldehyde and o-nitrobenzaldehyde crystallize and separate out from the reaction; after filtering, the crystals are put into the dissolution kettle, and an appropriate amount of water is added to heat up to 50 ° C, the crystals are melted, and the bottom is containing m-nitrobenzaldehyde The organic layer of nitrobenzaldehyde and o-nitrobenzaldehyde; the water layer enters the wastewater treatment station together with the water analysis wastewater fo...

Embodiment 2

[0028] Embodiment 2, a kind of production technique of m-nitrobenzaldehyde, its processing step is as follows:

[0029] (1) Nitration: Add sulfuric acid and nitric acid solution into the nitrification reaction kettle, pass through the insulation interlayer with frozen brine to cool down to 0°C, add benzaldehyde dropwise, keep warm for 3 hours after the dropwise addition, and analyze by sampling chromatography that the residual weight of benzaldehyde is 0.3% , the material is discharged into the ice water tank, and the m-nitrobenzaldehyde and o-nitrobenzaldehyde crystallized and precipitated; after filtration, the crystals are put into the dissolution kettle, and an appropriate amount of water is added to raise the temperature to 55°C. The crystals are melted and left standing. The organic layer of phenylbenzaldehyde and o-nitrobenzaldehyde; the water layer enters the wastewater treatment station together with the water analysis wastewater for pretreatment; the weight ratio of r...

Embodiment 3

[0035] Embodiment 3, a kind of production technique of m-nitrobenzaldehyde, its processing step is as follows:

[0036] (1) Nitration: Add sulfuric acid and nitric acid solution into the nitrification reaction kettle, pass through the insulation interlayer with frozen brine to cool down to -2°C, add benzaldehyde dropwise, keep warm for 2 hours after the dropwise addition, sample and chromatographically analyze the residual weight of benzaldehyde to 0.4% , the material is discharged into the ice water tank, and the m-nitrobenzaldehyde and o-nitrobenzaldehyde crystallized and precipitated; after filtration, the crystals are put into the dissolution kettle, and an appropriate amount of water is added to raise the temperature to 52°C. The crystals are melted and left standing. The organic layer of phenylbenzaldehyde and o-nitrobenzaldehyde; the water layer enters the waste water treatment station together with the water analysis wastewater for pretreatment; the weight ratio of raw ...

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Abstract

The invention relates to a production process of m-nitrobenzaldehyde. The production process is characterized in that based on benzaldehyde used as a raw material, m-nitrobenzaldehyde is prepared by the steps of nitration, addition, alkali precipitation, refining and the like. According to the production process provided by the invention, the content of o-position isomers is controlled below 15% through regulating nitration conditions; and by utilizing the large difference in dissolvability between m-nitrobenzaldehyde and addition products of o-position isomers is large, most of o-position isomers are separated out. By test, the chromatographic purity of the crude product prepared by the production process provided by the invention can reach 99.2%, the chromatographic purity of the refined product can reach above 99.9%, and the content of o-position isomers can be controlled below 0.06%.

Description

technical field [0001] The invention relates to a process for preparing m-nitrobenzaldehyde. Background technique [0002] The method for producing m-nitrobenzaldehyde in the present technology mainly adopts the method of refining after nitration of benzaldehyde, but because more than 20% ortho isomers are produced during nitration, it is difficult to achieve higher purity by conventional refining methods. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a production process of m-nitrobenzaldehyde which is more reasonable in process, safe in operation and can effectively improve product purity in view of the deficiencies in the prior art. [0004] The technical problem to be solved by the present invention is achieved through the following technical solutions. The present invention is a kind of production technique of m-nitrobenzaldehyde, and it is characterized in that, its processing step is as follows: [000...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C205/44C07C201/08C07C201/16
Inventor 张守平
Owner GUANNAN YISITE CHEM
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