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Method for producing pyromellitic dianhydride

A pyromellitic dianhydride and production method technology, applied in the direction of organic chemistry, can solve the problems of high waste treatment costs and high energy consumption in the production process of pyromellitic dianhydride, and achieve electricity saving, stable vacuum, and vacuum degree of effect

Inactive Publication Date: 2010-06-16
HUANGSHAN DEPING CHEM
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Problems solved by technology

[0010] In order to solve the problems of high energy consumption and high cost of waste treatment in the prior art pyromellitic dianhydride production process, the present invention provides a novel production method of pyromellitic dianhydride

Method used

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Embodiment

[0028] The main process of producing pyromellitic dianhydride (PMDA, referred to as homoanhydride) by durene air oxidation method is: oxidation, discharging, hydrolysis, centrifugation, dehydration and sublimation.

[0029] 1. Oxidation

[0030] Using durene and air as raw materials, the oxidation reaction is carried out through the catalyst at the higher temperature of the molten salt in the reactor to obtain a gas phase mixture, and the crude anhydride semi-finished product is recovered through three series-connected cooling traps, followed by four traps and self-designed installation 30m 2 The cyclone pulse bag filter collects and recycles the remaining powder to ensure that the washing wastewater is discharged up to the standard;

[0031] 2. Discharge

[0032] Clean up and rake out all the crude anhydride in the trap, pack them in bags according to the specified weight, weigh them, stack them neatly, and register the weight of the materials;

[0033] 3. Hydrolysis and c...

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Abstract

The invention relates to a method for producing pyromellitic dianhydride, which solves the problems of high energy consumption, high treatment cost of 'three wastes' and the like in the conventional production process. The process of the method comprises the following steps: 1, oxidization, namely taking durene and the air as raw materials, performing an oxidizing reaction in the presence of a catalyst at a high fused salt temperature in a reactor to prepare a gaseous phase mixture, and recovering a semi-finished product of crude anhydride through three tandem cold-traps; 2, discharging, namely cleaning raking out all crude anhydride in the cold-traps; 3, hydrolysis and centrifugation, namely heating the crude anhydride prepared by oxidation by steam in a soft water hydrolysis kettle to form liquid through smelting, hydrolyzing the liquid to form pyromellitic methanoic acid, performing recrystallization after the decoloration by activated carbon and heat filtration, and obtaining the eligible pyromellitic methanoic acid and crude tetracid crystals through centrifugation; and 4, performing dehydration and sublimation to obtain a product of the pure pyromellitic dianhydride. The method reduces the energy consumption, and can save the production cost of 1 million Yuan in the production of 100 tons of pyromellitic dianhydride.

Description

technical field [0001] The invention relates to a production process for producing pyromellitic dianhydride by adopting a durene air oxidation method. Background technique [0002] Pyromellitic dianhydride (PMDA) is a product formed by vacuum dehydration, sublimation and recrystallization of pyromellitic acid. The preliminary project uses the durene air oxidation method to produce pyromellitic acid semi-finished crude anhydride. There are two sets of production lines A and B. After several years of production, it is found that the originally designed production line has high consumption of raw material durene and other auxiliary energy sources, such as High consumption of electricity bills, washing sewage treatment costs, etc. The main deficiencies that exist: [0003] (1) Two sets of production lines A and B are each equipped with a 110KW RF-240 Roots blower, which has excess production capacity and high power consumption. [0004] (2) The amount of catalyst in the oxida...

Claims

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Application Information

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IPC IPC(8): C07D493/04
Inventor 周永明徐来炳黄亚平
Owner HUANGSHAN DEPING CHEM
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