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A kind of preparation method based on catalytic oxidation-hydrolysis-segmental crystallization to prepare pyromellitic acid

A technology of pyromellitic acid and pyromellitic dianhydride, which is applied in the field of preparation of pyromellitic acid based on catalytic oxidation-hydrolysis-segmented crystallization, which can solve the problem of difficult reaction raw materials, crystal hanging on the wall, and low product yield and other problems, to achieve the effect of improving crystallization efficiency, improving heat transfer efficiency, and uniform particle size

Active Publication Date: 2021-12-28
连云港鹏辰特种新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although pyromellitic acid is obtained in the above method, due to the agglomeration of the catalyst in the catalytic oxidation process, the reaction raw materials are difficult to fully contact with the catalyst, which easily causes low product yield, and in the crystallization process, the phenomenon of crystal hanging on the wall is prone to occur. resulting in low product yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A method for preparing pyromellitic acid based on catalytic oxidation-hydrolysis-segmented crystallization, comprising the following steps:

[0025] (1) Heat and melt durene at 90°C, filter it through a filter, mix it with air preheated at 190°C at a volume ratio of 0.001:1, and pump it into the vaporization mixer, heat and vaporize into a microchannel reactor coated with a vanadium-titanium coating supported by 5 μm mesoporous zirconia, and react at 350°C. Pyromellitic dianhydride;

[0026] (2) dissolving the crude pyromellitic dianhydride obtained above in an acetone solution, followed by crystallization and centrifugation; the centrifugal liquid obtained by centrifugation was subjected to atmospheric distillation at 40° C.;

[0027] (3) Add the solid obtained by centrifugation in step (2) and the distillation raffinate after atmospheric distillation into the hydrolysis kettle, and add water, carry out stirring and hydrolysis treatment at 90°C, filter after the hydro...

Embodiment 2

[0030] A method for preparing pyromellitic acid based on catalytic oxidation-hydrolysis-segmented crystallization, comprising the following steps:

[0031] (1) Heat and melt durene at 95°C, filter it through a filter, mix it with air preheated at 200°C at a volume ratio of 0.2:1, and pump it into the vaporization mixer. into a microchannel reactor coated with 20 μm mesoporous zirconia-loaded vanadium-titanium coating, and react at 380 ° C. After the reaction, the obtained gas is sequentially condensed by a condenser and collected by a trap to obtain crude Pyromellitic dianhydride;

[0032] (2) dissolving the crude pyromellitic dianhydride obtained above in an acetone solution, followed by crystallization and centrifugation; the centrifugal liquid obtained by centrifugation was subjected to atmospheric distillation at 45° C.;

[0033] (3) Add the solid obtained by centrifugation in step (2) and the distillation raffinate after atmospheric distillation into the hydrolysis kettl...

Embodiment 3

[0036] A method for preparing pyromellitic acid based on catalytic oxidation-hydrolysis-segmented crystallization, comprising the following steps:

[0037] (1) Heat and melt durene at 90°C, filter it through a filter, mix it with air preheated at 200°C at a volume ratio of 0.1:1, and pump it into the vaporization mixer. into a microchannel reactor coated with 15 μm mesoporous zirconia-loaded vanadium-titanium coating, and react at 350 ° C. After the reaction, the obtained gas is sequentially condensed by a condenser and captured by a trap to obtain crude Pyromellitic dianhydride;

[0038] (2) dissolving the crude pyromellitic dianhydride obtained above in an acetone solution, followed by crystallization and centrifugation; the centrifugal liquid obtained by centrifugation was subjected to atmospheric distillation at 45° C.;

[0039] (3) Add the solid obtained by centrifugation in step (2) and the distillation raffinate after atmospheric distillation into the hydrolysis kettle...

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Abstract

The invention discloses a preparation method for preparing pyromellitic acid based on catalytic oxidation-hydrolysis-segmented crystallization. The reaction is carried out in a microchannel reactor with a catalyst coating; the reacted gas is cooled and captured by a trap, cooled and crystallized, and then centrifuged. The centrifuged mother liquor is subjected to atmospheric distillation. The residual liquid is added into the hydrolysis kettle for hydrolysis treatment; finally, the hydrolysis liquid is filtered, and the filtrate is subjected to subsection cooling crystallization, centrifugation, and vacuum drying to obtain the target product, pyromellitic acid. The method is simple to operate, and the obtained target product has a high yield.

Description

Technical field: [0001] The invention relates to the field of pyromellitic acid preparation, in particular to a method for preparing pyromellitic acid based on catalytic oxidation-hydrolysis-segmented crystallization. Background technique: [0002] Pyromellitic acid is used in the synthesis of polyimide, octyl pyromellitate, etc. It is the main raw material for the production of matting curing agents, and is widely used in aerospace, aviation, electromechanical and electronics fields. It is also an important epoxy resin and Curing agent for polyester resin and auxiliary agent for powder coating. At present, the commonly used method is to use durene as a raw material to obtain it through gasification and oxidation followed by hydrolysis. [0003] The patent with the application number CN98116922.8 discloses the production method of durene, using durene or 5-isopropyl mesitylene as raw material, after vaporization, mixed with air, and entering into the column and tube reactio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/087C07C51/43C07C63/313C07D493/04B01J23/22
CPCC07C51/087C07C51/43C07D493/04B01J23/22C07C63/313
Inventor 江晓龙谈勇谈俊
Owner 连云港鹏辰特种新材料有限公司
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