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Purification method of crude benzenetetracarboxylic anhydride based on crystallization sublimation

A technology of pyromellitic dianhydride and purification method, which is applied in the direction of organic chemistry, can solve the problems of immaturity, achieve fast cooling speed, good heat exchange effect, and reduce the effect of water and water

Active Publication Date: 2018-07-27
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

It can be seen from the above prior art that the purification efficiency and purity of pyromellitic dianhydride can be improved by improving the trapping process, but many methods are still not mature enough and need to be further improved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Directly mix the hot gas flow from the reactor with durene as the raw material at a volume ratio of 1:0.5 with the inert gas containing ice flakes, wherein the content of ice flakes in the inert gas containing ice flakes is 1%, The gas velocity is 0.05m / s, collected by a column trap, and centrifuged to obtain the crude pyromellitic dianhydride.

[0025] (2) Add the molybdenum trioxide one-dimensional rod material into the PVP solution, raise the temperature to 120°C and react for 2 days, take out the crystal, wash, vacuum-dry, carbonize at 590°C, pickle with hydrofluoric acid, and obtain molybdenum oxide-containing Rod carbon material.

[0026] (3) Add the crude pyromellitic dianhydride into the hydrolysis kettle. The temperature of the steam in the hydrolysis kettle is 90°C and the pressure is 0.2MPa. The rod-shaped carbon material was stirred, hydrolyzed, decolorized, and hydrogenated for 3 hours, and then filtered to obtain crude hydrogenated pyromellitic acid c...

Embodiment 2

[0029] (1) Directly mix the hot gas flow from the reactor with durene as the raw material at a volume ratio of 1:0.8 with the inert gas containing ice flakes, wherein the content of ice flakes in the inert gas containing ice flakes is 4%, The gas velocity is 0.5m / s, collected by a column trap, and centrifuged to obtain the crude pyromellitic dianhydride.

[0030] (2) Add the molybdenum trioxide one-dimensional rod-shaped material into the PVP solution, raise the temperature to 130°C and react for 3 days, take out the crystal, wash, vacuum-dry, carbonize at 620°C, and pickle with hydrofluoric acid to obtain molybdenum oxide-containing Rod carbon material.

[0031] (3) Add the crude pyromellitic dianhydride to the hydrolysis kettle. The temperature of the steam in the hydrolysis kettle is 100°C and the pressure is 0.2MPa. The rod-shaped carbon material was stirred, hydrolyzed, decolorized and hydrogenated for 6 hours, and then filtered to obtain crude hydrogenated pyromellitic ...

Embodiment 3

[0034] (1) Directly mix the hot gas flow from the reactor with durene as the raw material at a volume ratio of 1:0.6 with the inert gas containing ice flakes, wherein the content of ice flakes in the inert gas containing ice flakes is 2%, The gas velocity is 0.15m / s, and it is collected by a column trap and centrifuged to obtain the crude pyromellitic dianhydride.

[0035] (2) Add the molybdenum trioxide one-dimensional rod material into the PVP solution, raise the temperature to 125°C and react for 2.5 days, take out the crystal, wash, vacuum dry, carbonize at 600°C, and pickle with hydrofluoric acid to obtain molybdenum oxide-containing rod-shaped carbon material.

[0036] (3) Add the crude pyromellitic dianhydride into the hydrolysis kettle. The temperature of the steam in the hydrolysis kettle is 95°C and the pressure is 0.2MPa. The rod-shaped carbon material was stirred, hydrolyzed, decolorized, and hydrogenated for 4 hours, and then filtered to obtain crude hydrogenated...

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PUM

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Abstract

The invention provides a purification method of crude benzenetetracarboxylic anhydride based on crystallization sublimation. The method concretely comprises the following steps of directly mixing hotair flow from a reactor using durene as raw materials and inert gas containing ice crystal sheets; performing collection through a cylindrical capture device; performing centrifugation to obtain a benzenetetracarboxylic anhydride crude product; adding molybdenum trioxide one-dimensional rod-shaped materials into a PVP solution; after the temperature rise reaction, performing washing drying, charring and acid washing to obtain the rod-shaped carbon materials containing molybdenum oxide; adding the benzenetetracarboxylic anhydride crude product into a hydrolysis kettle; adding the rod-shaped carbon materials containing molybdenum oxide; performing stirring hydrolysis decoloring hydrogenation treatment and filtering to obtain crude hydrogenated pyromellitic acid crystals; performing molten salt heating dewatering and sublimation treatment on the crude hydrogenated pyromellitic acid crystals to obtain benzenetetracarboxylic anhydride. The purification method has the advantages that the rawmaterials are directly in contact with the inert gas containing the ice crystal sheets to be captured, the rod-shaped carbon material containing molybdenum oxide is used for simultaneous hydrolysis decoloring hydrogenation reaction; the high-purity benzenetetracarboxylic anhydride is obtained.

Description

technical field [0001] The invention belongs to the technical field of pyromellitic dianhydride purification, and in particular relates to a method for purifying crude pyromellitic dianhydride based on crystal sublimation. Background technique [0002] Pyromellitic dianhydride, also known as homoanhydride, has a special molecular structure and can be used to manufacture materials with heat resistance, electrical insulation and chemical resistance, among which the most important use is as a unit of polyimide It is synthesized with aromatic diamines to obtain polyimide plastics, but the purity of pyromellitic dianhydride is very high, which needs to be more than 99%. At present, the purification methods of pyromellitic dianhydride include recrystallization method, solvent washing method, vacuum sublimation method, complex method, inert gas flow method, secondary distillation method, etc. [0003] Chinese patent CN 101580509B discloses a method for producing electronic-grade p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D493/04
CPCC07D493/04
Inventor 谈勇谈俊江晓龙
Owner 连云港鹏辰特种新材料有限公司
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