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Production process of p-nitrobenzaldehyde

A technology for producing p-nitrobenzaldehyde and its production process, which is applied in the field of preparing p-nitrobenzaldehyde, can solve problems such as unfavorable environmental operation, achieve the effects of improving utilization rate, high environmental protection and safety, and reducing the impact on the human body

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

AI Technical Summary

Problems solved by technology

This method has two defects. One is that bromination and oxidation use carbon tetrachloride, which has been banned in the world, as a solvent, and the other is that a large amount of hydrogen bromide gas produced during bromination is unfavorable to the environment and workers, and needs to be treated. The third is that the refined toluene with certain toxicity is used as solvent

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Embodiment 1, a kind of production technique of p-nitrobenzaldehyde, its steps are as follows:

[0029] (1) Bromination: Put water, dichloroethane, and p-nitrotoluene into a closed bromination reaction kettle, turn on the vacuum pump, and after the pressure in the kettle drops below 0.08MPa, add bromine, raise the temperature to 50°C, and trigger agent peroxydicarbonate (2-ethylhexyl) ester, continue to heat up to 60 ° C, after the reactant fades, add hydrogen peroxide and initiator peroxydicarbonate (2-ethylhexyl) ester in 2 batches, each time After the reactant fades, add it again; add hydrogen peroxide and initiator peroxydicarbonate (2-ethylhexyl) ester, and keep the reaction mixture for not less than 2 hours after the color fades to obtain the brominated solution; the raw material o-nitrotoluene , bromine, water, ethylene dichloride, hydrogen peroxide and the weight ratio of initiator are 1: 0.5: 2.3: 1.8: 0.4: 0.04;

[0030] (2) Hydrolysis: add sodium carbonate a...

Embodiment 2

[0035] Embodiment 2, a kind of production technique of p-nitrobenzaldehyde, its steps are as follows:

[0036](1) Bromination: Put water, dichloroethane, and p-nitrotoluene into a closed bromination reaction kettle, turn on the vacuum pump, and after the pressure in the kettle drops below 0.08MPa, add bromine, raise the temperature to 55°C, and trigger Agent peroxydicarbonate (2-ethylhexyl) ester, continue to heat up to 65 ° C, after the reactant fades, add hydrogen peroxide and initiator peroxydicarbonate (2-ethylhexyl) in 2 to 4 batches, Add each time after the reactant fades; add hydrogen peroxide and initiator peroxydicarbonate (2-ethylhexyl) ester, and keep the reaction mixture for not less than 2 hours after the color fades to obtain brominated solution; The weight ratio of methyl toluene, bromine, water, dichloroethane, hydrogen peroxide and initiator is 1: 0.7: 2.7: 2.2: 0.6: 0.06;

[0037] (2) Hydrolysis: Add an aqueous solution of sodium carbonate with a mass concen...

Embodiment 3

[0043] Embodiment 3, a kind of production technique of p-nitrobenzaldehyde, its steps are as follows:

[0044] (1) Bromination: Put water, dichloroethane, and p-nitrotoluene into a closed bromination reaction kettle, turn on the vacuum pump, and after the pressure in the kettle drops below 0.08MPa, add bromine, raise the temperature to 52°C, and trigger agent peroxydicarbonate (2-ethylhexyl) ester, continue to heat up to 62 ° C, after the reactant fades, add hydrogen peroxide and initiator peroxydicarbonate (2-ethylhexyl) ester in 3 batches, each time After the reactant fades, add it again; add hydrogen peroxide and initiator peroxydicarbonate (2-ethylhexyl) ester, and keep the reaction mixture for not less than 2 hours after the color fades to obtain the brominated solution; the raw material o-nitrotoluene , bromine, water, ethylene dichloride, hydrogen peroxide and initiator are in a weight ratio of 1: 0.6: 2.5: 2.0: 0.5: 0.05;

[0045] (2) Hydrolysis: Add sodium carbonate ...

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Abstract

The invention relates to a production process of p-nitrobenzaldehyde. The production process is characterized in that p-nitrobenzaldehyde is prepared by the sections of bromination, hydrolysis, oxidation, addition, alkali precipitation, refining and the like based on p-nitrotoluene as a raw material. According to the production process provided by the invention, a solvent used when bromination is carried out is dichlorethane, thereby avoiding the environmental protection problem brought by carbon tetrachloride; an unreacted raw material is used as the solvent when oxidation is carried out; when refining is carried out, 80% ethanol is used as the solvent, thereby reducing the influence of an toxic solvent on a human body; and when bromination is carried out, cheap hydrogen peroxide is added, thereby improving the utilization rate of bromine and avoiding the disadvantages of large amount of hydrogen bromide gases on environment and worker operation. Thus, the production process provided by the invention has higher environmental friendliness and safety, and is suitable for industrial production on large scale; and by test, the yield of p-nitrobenzaldehyde is above 65%, and the chromatographic purity of the finished product can reach above 99.5%.

Description

technical field [0001] The invention relates to a process for preparing p-nitrobenzaldehyde. Background technique [0002] What the production technique of preparing p-nitrobenzaldehyde in the prior art mainly adopts is a kind of three-step bromination method, is that p-nitrotoluene is brominated to p-nitrobenzyl bromide in the presence of an initiator, and then hydrolyzed to The corresponding benzyl alcohols are then oxidized to aldehydes. This method has two defects. One is that bromination and oxidation use carbon tetrachloride, which has been banned in the world, as a solvent, and the other is that a large amount of hydrogen bromide gas produced during bromination is unfavorable to the environment and workers, and needs to be treated. The 3rd, refining has adopted the toluene that certain toxicity is done solvent. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a production process of p-nitrobenzaldehyde wi...

Claims

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Application Information

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IPC IPC(8): C07C205/44C07C201/12
Inventor 张守平
Owner GUANNAN YISITE CHEM
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