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Method for synthesizing 2,3,3',4'-diphenyl ether tetracarboxylic acid

A technology for the synthesis of dimethyl diphenyl ether dicarboxylic acid, which is applied in the preparation of carboxylic acid salts, chemical instruments and methods, and the preparation of organic compounds, can solve the problems of low concentration, complicated operation, and high cost, and achieve the goal of reaction Mild conditions, high product purity and high production efficiency

Active Publication Date: 2014-12-10
SHANGHAI PLASTICS RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method has low concentration, low yield, large amount of raw materials, high cost, serious pollution, and more three wastes, which is not suitable for the needs of modern industrial production.
[0009] In order to avoid the use of potassium permanganate, the production method of pyromellitic dianhydride disclosed in patent CN1245171A is oxidized at high temperature (430~450°C), and the preparation of catalyst is complicated; the synthesis of 4,4'-ODPA disclosed in patent CN1706846A In the method, air is used for fixed-bed oxidation in the presence of a catalyst. This method has little pollution, but also requires high temperature (360~440°C); in the process for producing pyromellitic dianhydride disclosed in patent CN101037439A, carrier-type polyoxometallic acid is used Salt is used as a catalyst, but also requires high temperature (300~340°C)
In addition, there are reports of cobalt catalysis or cobalt-manganese-bromine system catalysis. Although it can be carried out in air, it requires very high pressure, complicated operation, and difficult to use in the actual production process.

Method used

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  • Method for synthesizing 2,3,3',4'-diphenyl ether tetracarboxylic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Taking the high-pressure valve as an example, add the dimethyl diphenyl ether dicarboxylic acid and 40% dilute nitric acid (the dimethyl diphenyl ether dicarboxylic acid and HNO 3 The molar ratio is preferably 1:4.4), close the lid of the kettle, stir and heat. Observe the experimental phenomena and record the changes of process parameters such as pressure and temperature.

[0030] As the temperature rises, the pressure of the system increases. When the temperature reaches 120~150°C, the reaction is initiated. The pressure is controlled at 1~3MPa, and the reaction is carried out at 120~150°C for 1~2 hours.

[0031] Then raise the temperature to 180~220℃, continue to control the pressure at 1~3MPa, and react for 0.5~2 hours.

[0032] After the reaction is completed, cool down to below 80°C, and slowly release the pressure to normal pressure. The reaction product was poured out and cooled naturally or placed in ice water for 6-12 hours, and crystallization appeared.

...

Embodiment 2

[0035] In the autoclave, add the dimethyl diphenyl ether dicarboxylic acid and 30% dilute nitric acid (the dimethyl diphenyl ether dicarboxylic acid and HNO 3 The molar ratio is preferably 1:6), close the lid of the kettle, stir and heat. Observe the experimental phenomena and record the changes of process parameters such as pressure and temperature.

[0036] As the temperature rises, the pressure of the system increases. When the temperature reaches 120~150°C, the reaction is initiated. The pressure is controlled at 1~3MPa, and the reaction is carried out at 120~150°C for 1~2 hours.

[0037] Then raise the temperature to 180~220℃, continue to control the pressure at 1~3MPa, and react for 0.5~2 hours.

[0038] After the reaction was completed, the temperature was cooled, and the pressure was slowly released to normal pressure. The reaction product was poured out and cooled naturally or placed in ice water for 6-12 hours, and crystallization appeared.

[0039] After filterin...

Embodiment 3

[0041] In the autoclave, add the dimethyl diphenyl ether dicarboxylic acid and 20% dilute nitric acid (the dimethyl diphenyl ether dicarboxylic acid and HNO 3 The molar ratio is preferably 1:8), close the lid of the kettle, stir and heat. Observe the experimental phenomena and record the changes of process parameters such as pressure and temperature.

[0042] As the temperature rises, the pressure of the system increases. When the temperature reaches 120~150°C, the reaction is initiated. The pressure is controlled at 1~3MPa, and the reaction is carried out at 120~150°C for 1~2 hours.

[0043] Then raise the temperature to 180~220℃, continue to control the pressure at 1~3MPa, and react for 0.5~2 hours.

[0044] After the reaction was completed, the temperature was cooled, and the pressure was slowly released to normal pressure. The reaction product was poured out and cooled naturally or placed in ice water for 6-12 hours, and crystallization appeared.

[0045] After filterin...

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Abstract

The invention provides a method for synthesizing 2,3,3',4'-diphenyl ether tetracarboxylic acid. The method comprises the steps of: adopting dilute nitric acid as an oxidant, and preparing the 2,3,3',4'-diphenyl ether tetracarboxylic acid by a way of two-stage heating reaction. The method is high in yield, few in byproducts and high in product purity, and is capable of greatly reducing the polyimide synthesizing cost as an important step in a process of synthesizing isomeric polyimide and polyimide monomer.

Description

technical field [0001] The invention relates to a method for synthesizing organic compounds, in particular to a method for synthesizing polyimide monomers. Background technique [0002] Polyimide has good high temperature resistance and low temperature resistance, and can be used for a long time in an environment of -200 ° C ~ 300 ° C; it has good mechanical properties, good dielectric properties, and high radiation resistance. It is a comprehensive performance It is an excellent engineering material, and its application in functional materials is also under study. At present, polyimide has been widely used in aerospace, microelectronics, liquid crystal display, separation membrane and laser and other fields. [0003] Since polyimide is difficult to melt and its solubility is poor, processing is difficult. Therefore, extensive research has been carried out to improve the processing performance of polyimide as an example. Among them, 3,3',4,4'-diphenyl ether tetracarboxylic ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C65/24C07C51/275
Inventor 吕凯朱博超
Owner SHANGHAI PLASTICS RES INST CO LTD
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