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Method for preparing diphenyl tetracarboxylic dianhydride

A technology of biphenyltetracarboxylic dianhydride and biphenyltetracarboxylic acid, which is applied in the field of preparing biphenyltetracarboxylic dianhydride, can solve the problems of harsh equipment and reaction conditions, difficulty in large-scale production, etc., and achieve low price and simple production process Effect

Active Publication Date: 2010-03-03
常熟华虞环境科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it is difficult to produce on a large scale due to its strict requirements on equipment and reaction conditions.

Method used

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  • Method for preparing diphenyl tetracarboxylic dianhydride
  • Method for preparing diphenyl tetracarboxylic dianhydride
  • Method for preparing diphenyl tetracarboxylic dianhydride

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preparation example Construction

[0015] A kind of preparation method of biphenyltetracarboxylic dianhydride comprises following reaction:

[0016] Halogenation reaction: using o-xylene as a raw material for halogenation to obtain halogenated xylene;

[0017] Coupling reaction: 3,3',4,4'-tetramethylbiphenyl is prepared by coupling halogenated xylene;

[0018] Oxidation reaction: 3,3',4,4'-tetramethylbiphenyl is oxidized to produce 3,3',4,4'-biphenyltetracarboxylic acid;

[0019] Dehydration reaction: 3,3',4,4'-biphenyltetracarboxylic acid is dehydrated to obtain 3,3',4,4'-biphenyltetracarboxylic dianhydride.

[0020] The halogenation reaction is a reaction in the presence of a halogen and a catalyst using o-xylene as a raw material.

[0021] The catalyst is iron and iodine, wherein the molar ratio of iron and iodine is greater than zero and less than or equal to 1:1, wherein 0.1:1, 0.5:1, and 1:1 all have good effects.

[0022] In the halogenation reaction, the molar ratio of o-xylene, catalyst and halogen ...

Embodiment 1

[0040] (1) Preparation of halogenated o-xylene by halogenation reaction

[0041]

[0042] Add 500 g (569 ml, 4.72 moles) of o-xylene, 2.5 grams of iron powder and 2.5 grams of iodine into a 1000ML four-necked bottle. Install a dropping funnel, a stirrer, a condenser tube, a thermometer, and connect a gas absorption device to the top of the condenser tube. The reaction mixture was stirred and cooled to -5°C-5°C under an ice bath, and 660 g (4.13 moles) of liquid bromine was slowly added into the reaction flask, and the addition was controlled within 3 hours. During this period, the temperature of the reaction solution was always controlled at -5°C-5°C. After all the liquid bromine was added, the temperature of the reaction solution was allowed to rise to room temperature, and stood still overnight. Then the reaction solution was poured into 500ML water, stirred and separated. Then wash twice with 3% sodium hydroxide solution. Then wash twice with 500ML water, separate the...

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Abstract

The invention relates to a method for preparing diphenyl tetracarboxylic dianhydride. The diphenyl tetracarboxylic dianhydride is prepared by taking o-xylene as a raw material through halogenating, coupling, oxidation and dehydration. In the method, the conversion rate of the o-xylene is 100 percent; and the total yield of the diphenyl tetracarboxylic dianhydride is 55 percent, the melting range is between 298 and 301 DEG C, and the purity is between 99.5 and 99.8 percent. The diphenyl tetracarboxylic dianhydride uses the o-xylene as the raw material instead of chloro-anhydride by coupling first and then oxidizing, so the experimental route and the method are simple, economic and easy to operate. At the same time, because potassium permanganate with low price is adopted as an oxidant, an industrial preparation method, which is simple, convenient and economic and has low requirements on equipment, is provided.

Description

technical field [0001] The invention relates to a preparation method of biphenyltetracarboxylic dianhydride, in particular to a method for preparing biphenyltetracarboxylic dianhydride by using o-xylene as a raw material. Background technique [0002] Biphenyltetracarboxylic dianhydride (BPDA for short) is an extremely important polymer precursor, which can be polymerized with various substances to form polyimide. Polyimide is currently the most heat-resistant variety among industrialized polymer materials. Due to its superior comprehensive performance, it can be used as films, coatings, plastics, composite materials, adhesives, foam plastics, fibers, separation membranes, liquid crystals, etc. Alignment agents, photoresists, etc. are widely used in high-tech fields. Therefore, as an important monomer of high-performance polyimide, biphenyltetracarboxylic dianhydride has received extensive attention both at home and abroad for its synthesis and application. [0003] At pre...

Claims

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Application Information

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IPC IPC(8): C07D307/60
Inventor 彭卫国赖学平崔玮乾隆
Owner 常熟华虞环境科技有限公司
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